A retrospective repeated cross sectional study assessing changes in the prevalence of apical periodontitis associated with the endodontic status and DMFT scores of patients in two adult cohorts (2008/2009 and 2018/2019) attending a UK dental hospital.

A retrospective repeated cross sectional study assessing changes in the prevalence of apical periodontitis associated with the endodontic status and DMFT scores of patients in two adult cohorts (2008/2009 and 2018/2019) attending a UK dental hospital. | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research A retrospective repeated cross sectional study assessing changes in the prevalence of apical periodontitis associated with the endodontic status and DMFT scores of patients in two adult cohorts (2008/2009 and 2018/2019) attending a UK dental hospital. Francesco Mannocci, Chetan morjaria, Filippo Cavalli This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5710951/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 14 Aug, 2025 Read the published version in British Dental Journal → Version 1 posted 9 You are reading this latest preprint version Abstract Aim: To compare the prevalence of apical periodontitis (AP), endodontic treatments, quality of endodontic treatments and their association with apical radiolucencies and DMFT scores, in patients attending a British National Health Service (NHS) Hospital in 2008-2009 (Cohort 1/C1) and 2018-2019 (Cohort 2/C2). Methodology Randomly selected panoramic radiographs of 980 patients, evenly distributed into two cohorts: C1 (2008-2009) and C2 (2018-2019), were retrospectively analysed. Patient demographics, number of teeth, presence and quality of endodontic treatments, apical radiolucencies in treated and untreated teeth, endodontic treatment quality, apical periodontitis prevalence by tooth type and DMFT scores were compared. Results: C1 had significantly higher DMFT scores (p<0.001), but similar numbers of teeth to C2. Patients with apical periodontitis had higher DMFT scores and lower number of molars (p<0.001). Similar percentages of untreated teeth had apical periodontitis in C1 (3.4%) and C2 (2.9%) but at a patient level, C2 had significantly fewer endodontic treatments (48.2% vs 41.2%; p=0.015), less apical disease (51%, vs 44%; p=0.04) and fewer endodontically treated teeth (5.5% vs 4.2%; p=0.007). The percentage of endodontically treated teeth with apical periodontitis was similar (29.3%, vs 27.9%). C2 patients had less unsatisfactorily obturated teeth (63.7% vs 57.6%) which was short of significance (p=0.072). C2 had fewer endodontically treated anterior teeth (p<0.001) but a higher proportion of endodontically treated molars (20.2%, vs 28.7%; p=0.003). A close to significant improvement in the quality of molars’ root canal treatments in C2 was noted (well-obturated teeth C1: 23.48%, c2: 35.11%; p=0.061). Conclusion A reduction of caries and endodontic disease burden and a slight improvement in the quality of endodontic treatments in the 2018/2019 cohort was observed. This was not accompanied by increased tooth retention. Health sciences/Health care/Dentistry/Dental public health/Dental epidemiology Health sciences/Health care/Dentistry/Endodontics/Root canal treatment Figures Figure 1 INTRODUCTION Apical periodontitis is an inflammatory response of the periapical tissues caused by the presence of microbes within the root canal system of an infected tooth ( 1 , 2 ). Bacteria may enter the pulp space through breaches in the dental hard tissue barrier ( 3 ) most commonly due to the carious process, but also through trauma-induced fractures and cracks, tooth surface loss, iatrogenic damage to teeth and periodontal disease. Changes in the prevalence of apical periodontitis would therefore occur if the causes of microbial ingress were prevented, if teeth affected by apical periodontitis were effectively treated to allow periapical inflammation to resolve and radiographic healing to occur; or if teeth affected by apical periodontitis were extracted. Whilst endodontic outcome studies have reported success rates of approximately 80–90% ( 4 , 5 ), such studies are generally carried out in secondary care or specialist settings, which account for the minority of endodontic treatments undertaken within the population. This may create problems when translating these outcomes into the general population where the vast majority of endodontic treatments are carried out in general dental practice ( 6 ). Although cross-sectional studies do not provide information on treatment outcome, they do provide insight into the presence of disease ( 6 ). Repeated cross-sectional studies can analyse trends in disease prevalence ( 7 ) and provide insight into the effectiveness of past public health resource allocation and potential future prevention and treatment strategies( 8 ). In radiographic surveys, high levels of apical periodontitis have been reported globally ( 9 ). The extent and quality of root canal fillings have also been reviewed as an assessment and prognostic tool( 10 ). They can act as a crude surrogate method of extrapolating the extent of apical disinfection and entombment of residual bacteria and apical sealing ( 10 , 11 ). Fewer studies are available to associate tooth type presence with apical disease levels in cross-sectional studies, despite this being an important potential confounder when assessing the prevelance of apical disease ( 6 ). Attempts to correlate changes in apical periodontitis with decayed, missing and filled teeth (DMFT) scores are also lacking. It has been found that multiple carious lesions, inadequate coronal restorations and high DMFT scores are risk indicators of apical periodontitis ( 12 ) ( 13 ). In the UK, general dentistry is predominantly carried out in government subsidised NHS dental settings, where the funding structure has been deemed inadequate and not fit for purpose ( 14 , 15 ) Furthermore, the problem is accentuated as the UK has an aging population and caries prevalence has been shown to increase with age in every time period ( 16 ). However more positively, in the UK, dental health surveys over 50 years have shown consistent reductions in dental disease by measure of tooth loss and edentulism ( 17 ). Improvements in endodontic undergraduate training across dental schools in the UK have been observed ( 18 ) and advances in endodontic techniques such as the developments in nickel-titanium instruments have meant that root canal treatments may be carried out more predictably, especially in less experienced clinician groups ( 4 , 19 , 20 , 21 , 22 , 23 )) whilst the barriers to their usage ( 24 ) have also reduced. To our knowledge, no repeated cross-sectional study has investigated the association between changes in DMFT, tooth type presence, quality of root canal obturations and prevalence of apical periodontitis. The aims of the study are therefore to: 1. Compare from panoramic radiographs, the prevalence of apical periodontitis affecting endodontically treated and non-endodontically treated teeth in patients referred to a British National Health Service (NHS) Hospital in 2008–2009 (cohort 1) and 2018–2019 (cohort 2). 2. Compare the quality of endodontic treatments of the two cohorts of patients and assess the association between quality of root canal treatments and radiographic detection of apical disease. 3. Record DMFT scores of the patients to provide comparison between cohorts and associations with the presence of apical periodontitis. MATERIALS AND METHODS This retrospective cross-sectional study examined panoramic radiographs from a total of 980 patients, evenly distributed in two time periods: 2008-2009 (490 patients) and 2018-2019 (490 patients). All panoramic radiographs were obtained from a single centre, anonymised in anonymized , which serves a wide geographic area encompassing anonymized in the UK. The collected radiographs included those taken for any reason in the departments of oral surgery, restorative dentistry, and endodontics. Trained and qualified radiographers used two panoramic radiograph machines (PM-2002-CC, PROMAX or PRO ONE; Planmeca Helsinki, Finland) to capture the radiographs. These radiographs were stored in the hospital database. To ensure comparability between the cohorts, all patients who had panoramic radiographs within the respective time periods were sorted by age using a radiography software (Planmeca Romexis dental imaging software; Planmeca; Helsinki, Finland). The patients were then divided into seven age groups, and 70 patients from each age group were randomly selected using a random number generator. An overview of the process of radiograph collection is given in Figure 1. Two calibrated examiners with similar clinical experience independently assessed the collected radiographs. Prior to the study, calibration was conducted using 15 radiographs not included in this research. The examiners used the same examination room, lighting conditions, 15-inch computer screens (Hewlett-Packard, USA), and assessed the radiographs individually at similar times of day. They utilized the same radiographic software and were experienced in digital radiography. They were permitted to adjust magnification, brightness and contrast to optimize detection(25). Any disagreements between the examiners were discussed and resolved through consensus. If a patient had multiple panoramic radiographs taken within the same year, the first radiograph of acceptable quality was used. Panoramic radiographs were excluded from the study following the criteria reported in table1.The data collected from each panoramic radiograph are reported in table 2. Table 1 Exclusion Criteria Exclusion criteria: Radiographs of insufficient diagnostic quality according to existing literature (26) Patients under 18 years old Edentulous patients Sectional radiographs Patients in the second cohort (2018-2019) who were already included in the first cohort (2008-2009). Table 2 Data Collected Parameter measured Method of collection Patient age at the time of exposure Calculated from date of exposure of radiograph and patient date of birth information on file Sex Data on file Number of erupted teeth present From panoramic radiograph excluding third molar teeth (0-28) Number of untreated teeth with apical radiolucency From panoramic radiograph (0 to 28) Number of teeth with satisfactory endodontic treatment Number of teeth with sub-optimal endodontic obturation The presence of apical radiolucencies in endodontically treated teeth From panoramic radiograph. Where intra radicular material was present, the tooth was noted as endodontically treated. The presence of associated apical periodontitis was noted (Y/N) Whether either satisfactorily or sub-optimally obturated teeth were associated with periapical lesions From panoramic radiograph. Based on criteria below. (satisfactory obturation Y/N or unsatisfactory obturation Y/N) The presence of apical radiolucency in each given patient regardless of the number or treatment status of the teeth Total number of apical radiolucencies per patient. (0-28) DMFT scores of each patient From panoramic radiograph. Based on World Health Organisation guidelines (27). excluding third molars. Number of teeth decayed, filled and missing noted. The number of molar teeth present From panoramic radiograph. Excluding third molars (0 to 8) The quality of root canal obturation in different tooth types (anterior, premolar, or molar) and the presence of apical radiolucency associated with those teeth. From panoramic radiograph. For each patient, endodontically treated teeth were allocated into one of 6 categories based on 3 tooth types (anterior, premolar and molar) and 2 obturation quality sub types (satisfactory /unsatisfactory) As listed in Table 2, the number of erupted teeth in each patient's radiograph was noted, irrespective of the condition of the tooth crown. The presence of apical disease and the quality of endodontic treatment was measured in a similar manner to previous studies (28, 29, 30) and following ESE guidelines (31). A root was deemed to have apical radiolucency if the periodontal ligament space was twice the width of the lateral periodontal space or a radiolucency in connection with the apical part of the root was present (32). For multi-rooted teeth, if any root displayed any of these radiographic signs, the tooth was classified as having apical periodontitis. A tooth was considered endodontically treated if radiopaque material was visible in the pulp chamber and/or root canals. Obturation was deemed to be satisfactory if the following criteria were met for all roots of a tooth (28, 29, 30) and ESE guidelines (31): Root canal filling material should reach within approximately 2 mm of the radiographic apex of the tooth, the distance from the apex was approximately measured using the measuring tool available in the Romexis software. Without obvious extrusion beyond the apex The root canal filling should be free of voids or gaps. If any of the above criteria were not met, the obturation was recorded as unsatisfactory. Because of the use of only retrospective fully anonymised data, this study was a non-intervention clinical trial, adopting a standardised non-experimental protocol, GERRI Oversite Committee ethical approval was obtained (Rec Reference: 20/EM/0112). The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist and statement were followed. Data Management All the information was transferred to a secure Excel spreadsheet. Data were analysed using SPSS software version 15 (version 15; SPSS Inc.). The statistical analysis consisted of a description of categorical variables (absolute and relative frequencies) and continuous variables (mean, standard deviation, median and range) for the total sample and differentiation by groups. Sample size calculation & statistical analysis A sample size of 980 patients (490/490) provides a maximum error of 4.43% in order to estimate the true AP prevalence in each one of both populations, assuming p=q=50% and confidence 95%. Moreover, we reach 95.1% of power to detect AP rates at 20% and 30% as significantly different in both groups using a logistic regression model and assuming a confidence level of 95%. At patient-level, a simple binary logistic regression model was conducted to assess the relationship between prevalence of AP and group. Odds ratio (OR) and 95% confidence intervals were obtained. Then, logistic models were adjusted by gender and age, and adjusted OR were obtained. Chi 2 and independent t-test were performed to assess the homogeneity of cohorts by sex and age and significance of DMFT data. At tooth-level, a multi-level logistic regression using generalized estimation equations (GEE) was conducted to assess the risk of AP in a tooth by the previously mentioned factors. Adjusted odds ratio and 95% confidence intervals were obtained from the Wald´s Chi 2 statistic. Similar linear models using GEE approach were estimated to analyze dependent variables as number of teeth under a specific condition. Beta coefficients and 95% confidence intervals were obtained. The significance level used in analysis was set at 5% (α=0.05). RESULTS The sample included 980 Panoramic radiographs from 980 different patients divided into two cohorts, Cohort 1: 2008-2009 (n=490) and Cohort 2 : 2018-2019 (n=490). There were 434 male (44.3%) and 546 female (55.7%), averaging 52.4 years of age. A total of 22,623 teeth were analyzed. Patient level analysis Prevalence of apical radiolucencies Out of 490 patients, 250 (51%) of patients had at least one tooth with apical disease in Cohort 1 compared to 219 (44.7%) in Cohort 2. There was a statistically significant difference in the percentage of patients with apical radiolucencies between groups (p=0.04 95% CI 0.59-0.98) Patients in cohort 2 had on average 0.16 fewer teeth affected by apical periodontitis than patients in cohort 1 and a 22% reduced risk of AP (OR=0.78; 95% CI: 0.60-0.99). Apical radiolucencies in untreated teeth In cohort 1, 37.8% of patients (185 out of 490) had an apical radiolucency in at least one untreated tooth. In comparison, 32.4% of patients (159 out of 490) in cohort 2 had an apical radiolucency in at least one untreated tooth, the difference was not significant (OR=0.79; 95%CI: 0.61-1.03; p=0.082). Endodontic treatment 236 patients had at least one endodontically treated tooth in cohort 1, compared with 202 in cohort 2. This reduction was significant (95% CI: -0.5 - - .05, p=0.015). On average, patients had 0.28 fewer endodontically treated teeth in the latter cohort. There was no difference between genders in the number of endodontic treatments for either cohort, though both cohorts showed a statistically significant increase in the number of endodontically treated teeth with age (p<0.001). Number of teeth present and DMFT scores The number of teeth present was not significantly different between patients of the two cohorts (p=0.212). 11,173 erupted teeth were present in the 490 patients analyzed in the 2008-2009 cohort whilst 11,451 erupted teeth were present in the 490 patients analyzed in the 2018-2019 cohort. There was no significant difference (p=0.522) between the mean number of molars per patient (5.01 in cohort 1 vs 5.12 in cohort 2). Significant differences between decayed, missing and filled teeth scores were found between cohorts (p<0.001). Patients from cohort 1 had a mean DMFT of 15.28, whereas in 2018 this was reduced to 12.81. The significant difference in DMFT scores but similarity in number of teeth and number molar teeth is indicative of a difference in decayed and filled teeth. An analysis of decayed and filled teeth (‘DFT’) was undertaken by removing the number of missing teeth from the DMFT score. The average DFT score in cohort 1 was 9.3 and in cohort 2 it was 7.53. The results showed a significant difference in DFT scores (p<0.001). Number of Molar teeth and Apical periodontitis Patients who had apical periodontitis across the two cohorts had a statistically significant lower number of molar teeth present (p<0.001). However, statistical significance was not found when comparing the difference in the number of molar teeth present in patients with apical periodontitis (p=0.269) or without apical periodontitis (p=0.502) Gender, age and apical periodontitis In cohort 1, there were 215 males (43.9%) and 275 females (55.7%). In Cohort 2, there were 219 males (44.7%) and 271 females (55.3%). The groups were homogeneous with regards to this variable (p=0.797). Overall, age and gender had a significant impact on the risk of apical periodontitis. Each additional year implied an increase in risk of apical periodontitis by 1.5% (p=0.001) or 0.006 more teeth (p=0.01). The increase in prevalence of apical periodontitis with age was also evident for both cohorts analyzed individually (p=0.0005). Females had a 27% lower risk of apical periodontitis compared to males (p=0.014) or 0.29 fewer teeth affected by apical periodontitis (p=0.003), this difference prevalence was statistically significant in Cohort 1only (p=0.009) and not in Cohort 2 (p=0.193). DMFT and Number of Molars by Age group and Gender In both cohorts individually and overall, there were significant differences between DMFT scores by age decade and number of molars by age decade. (p<0.001,). DMFT scores increased as the age of the patients increased whilst the number of molars reduced. However, by gender the samples did not show significant differences in DMFT scores or number of molars. DMFT and apical periodontitis DMFT scores were significantly higher in patients affected by apical periodontitis overall and in both individual cohorts (p<0.001). Table 3 DMFT scores in patients with AP in both cohorts Cohort 1 (2008/2009) Cohort 2 (2018/2019) P Value Mean DMFT score in patients without AP 12.43 10.8 P<0.05 Mean DMFT score in patients with AP 18.03 15.24 P<0.001 A significant association (p<0.001) between DMFT scores and apical radiolucencies in untreated teeth could also be made in the overall sample and in both cohorts individually. Similarly, there was an association between the number of Molar teeth and the presence of apical radiolucencies in the overall sample and in both cohorts individually Patients who had apical periodontitis had a statistically significant lower number of molar teeth present (p<0.001). Tooth level analysis Number of Teeth: In cohort 1, 11,172 teeth were analyzed. In cohort 2, 11,451 teeth were analyzed. The groups were homogeneous (p=0.212). Prevalence of apical radiolucencies in untreated teeth The prevalence of apical radiolucencies was not significantly different between cohorts. 3.4% of untreated teeth showed apical disease in cohort 1 and 2.9% in cohort 2 (p=0.98). Prevalence of endodontic treatments There was a significant difference in the number of teeth which were endodontically treated with 611 teeth (5.5%) being endodontically treated in cohort 1 whilst 476 (4.2%) were treated in cohort 2 (95% CI: 0.60-0.92, p=0.007). This equates to a 25% lower chance of a tooth having endodontic treatment in 2018/2019 compared to 2008/2009 Endodontic treatment and apical radiolucencies Though there was a difference in the number of endodontic treatments, the percentage of root treated teeth presenting with apical radiolucencies did not show any significant difference (p=0.772). 179 of the 611 (29.3%) of the endodontically treated teeth had apical periodontitis in Cohort 1 compared to 133 of 476 (27.9%) in cohort 2. Differences in endodontically treated tooth types between cohorts 126 anterior teeth were treated in cohort 2 which was significantly lower compared to the 227 treated in cohort 1 (p<0.001). The number of premolar and molar teeth treated was however similar. However, it was noted that whilst the numbers appeared to be similar, since there was a difference in the number of endodontically treated teeth for each cohort, when the proportion of endodontically treated teeth for each tooth type was calculated, a significant increase of the proportion of root canal treated molars became evident (cohort 1: 20.2%, cohort 2: 28.7%; p=0.003). as shown in table 7. Quality of endodontic treatment The overall percentage of suboptimal obturated teeth was 63.7%, in cohort 1 whilst it was 57.6% in cohort 2. There was a 32% higher chance of a satisfactory obturation in cohort 2 compared to cohort 1 (OR=1.32; 95%CI: 0.98-1.78). 389 (63.7%) of teeth were unsatisfactorily obturated in cohort 1 compared with 274 (57.6%) in cohort 2, However, this was short of significance for both obturation qualities (p=0.072). Quality of endodontic treatment and apical periodontitis There was no difference in the prevalence of apical periodontitis in satisfactory (p=0.598) and unsatisfactory obturations between cohorts (p=0.405). In both cohorts there was a significantly lower prevalence of apical periodontitis in well obturated teeth compared to teeth with suboptimal obturations (cohort 1: 18.9% vs 34.2%, cohort 2 16.3% vs36.9%) (P <0.001). Analysis of endodontically treated teeth Quality of treatment by tooth type Although there were improvements in quality of obturation for each tooth type in cohort 2 (2018-2019), the differences did not reach statistical significance However, a close to significant difference between molar teeth in cohort 1 and cohort 2 was reached (p=0.061). The prevalence of apical periodontitis was examined in both satisfactorily and unsatisfactorily obturated teeth and broken down by tooth type. However, for each tooth type in the same quality subgroup, there was no difference between cohorts. Assessing quality, there were significant differences between tooth types when the data for the two cohorts was combined. Anterior teeth had the lowest percentage of unsatisfactory obturations (45.3%) followed by premolars (60%) and finally molars (73.3%) (P <0.001). Apical periodontitis in endodontically treated teeth When cohorts were combined, endodontically treated premolars had the lowest percentage of apical periodontitis (20.3%), followed by anterior teeth (29.9%) and lastly molar teeth (34.9%). This was significantly lower than the anterior and molar groups (p<0.001). 28.4% of endodontically treated anterior teeth had apical periodontitis compared with 34.9% of Molar teeth, however this difference was not statistically significant (p=0.20). Where treatment was suboptimal, the rate of apical periodontitis in premolar (26.9%) and anterior teeth (37.7%) was significantly different (p=0.023). However, the prevalence of apical periodontitis in sub-optimally endodontically treated molar teeth (41.1%) was significantly greater than premolar teeth (p=0.002) but not significantly different than that of anterior teeth. Where treatment was satisfactory, there were significant differences between tooth types (p=0.015). The prevalence of apical periodontitis was higher in anterior teeth (23.4%) compared with premolar teeth (10.3%) (p=0.004). However, well obturated molar teeth had apical periodontitis in 19.1% of cases which was similar to anterior teeth, but just below statistical significance compared to premolars (p=0.061). Table 7 Numbers and proportions of endodontically treated teeth by tooth type for each cohort Cohort 1 (2008/2009) Cohort 2 (2018/2019) P Value Anterior teeth as a proportion of endodontically treated teeth 37.2% (227 teeth) 26.5% (126 teeth) <0.001 Premolar teeth as a proportion of endodontically treated teeth 32.6% (199 teeth) 34.9% (166 teeth) 0.426 Molar teeth as a proportion of endodontically treated teeth 30.2% (185 teeth) 38.7% (184 teeth) 0.003 Quality of Obturation in different tooth types Table 8 Comparison of quality of endodontic treatment for each tooth type Cohort 1 (2008/2009) Cohort 2 (2018/2019) Satisfactorily Obturated Unsatisfactorily Obturated Satisfactorily Obturated Unsatisfactorily Obturated Anterior teeth 81 (51.9%) 75 (48 %) 56 (60.2%) 37 (39.8%) Premolar teeth 59 (39%) 92 (60.9%) 57 (46.3%) 66 (53.7%) Molar teeth 31 (23.5%) 101 (76.5%) 46 (35.1%) 85 (64.9%) DISCUSSION In this repeated cross-sectional study of panoramic radiographs from 2008/2009 and 2018/2019, we found in the latter cohort a significant reduction in DMFT scores, a significant reduction of the number of patients with apical periodontitis, a significant reduction of the number of patients with endodontically treated teeth, a reduction in patients with untreated teeth with apical periodontitis, a lower number of endodontically treated teeth, a lower number of endodontically treated teeth with suboptimal treatments, a significantly lower number of root canal treated anterior teeth and a significantly higher proportion of root canal treated molars. This data suggests a general reduction of caries and endodontic disease burden and a general improvement in the apparent quality of endodontic treatments in this hospital adult patient population. Typically, patients are referred to any one of the dental specialities within the hospital from primary dental care settings for specialist assessment or treatment where required. However, in most cases, the majority of the dental treatment that patients have had, have been from primary dental care settings outside the hospital, such as NHS general dental practices. During the periods of interest, most panoramic radiographs would have been carried out for UK residents, however we cannot make the assumption that this population is representative of the general population of UK. Whilst our results did find a significant reduction in DMFT scores over time, this was largely due a significant reduction in filled and decayed teeth as the average number of teeth per patient was similar in both cohorts. This suggests that patients in 2018/2019 have a higher proportion of missing teeth compared to the number of decayed and filled teeth. This could be a result of more extractions and reduced complex restorative work being carried out relative to their disease levels, as a result of the implementation of the new NHS contract in 2006 ( 33 ). Renumeration has been shown to affect treatment delivery ( 34 , 35 ). The new contract changed the way general dentists are renumerated from a fee per item model to being paid a fee based upon the band in which the treatment carried out fell into. The model paid dentists based on the highest banded treatment type and did not consider the quantity of treatment provided, and so a single filling or extraction would attract the same fee as multiple fillings and root canal treatments. It is likely that dentists attempted to hit their contract targets in the most efficient way possible, i.e. shifting towards treatments where rewards are high relative to costs and time such as extractions, as opposed to selecting on the basis of clinical factors ( 33 ). An alternative reasoning for the lower number of decayed and filled teeth relative to missing teeth in the second cohort may be because of recent improvements in caries rates at an individual level. This would result in individuals experiencing less decay and having fewer restorations placed whilst the number of missing teeth remaining similar to cohort 1 may be as a result of higher caries experience and intervention which led to a higher number of extractions from the more distant past. There was a significant association between age group and DMFT score and apical periodontitis prevalence. For each additional year there was a 1.5% increase in apical periodontitis. Some studies have recorded an association of age and higher level of dental caries, however, the last UK adult dental health survey ( 17 ) found that younger patients had a higher levels of dental caries than older patients, though older patients had more restorations. Given that levels of apical periodontitis increased with age, this could indicate that it is not necessarily the presence of caries, which is a risk factor, but previous caries experience, which leads to deeper restorations and secondary lesions, which more quickly affect the pulp tissue. The association of older age with an increased likelihood of detecting apical periodontitis has been reported in a number of other studies ( 36 , 37 ) ( 38 ). Though DMFT scores were higher in older age groups, there was no difference in either DMFT scores or number of teeth by gender. However, there was a significantly lower number of teeth with apical pathology (27%) in female patients compared to males. Assessing individual cohorts, this significant difference was present in cohort 1, however the difference was not significant in cohort 2. The adult dental health survey found increased caries experience in males ( 17 ). Interestingly, other studies from different populations have found decreased caries experience in males ( 39 , 40 , 41 ), though the cause of this is likely to be multifactorial( 41 ). A corelation between DMFT scores and the presence of apical periodontitis ( 38 , 42 ) has been shown and the data from this study supports this. A clear association is seen between DMFT scores, the number of missing molar teeth, the presence of untreated apical disease and the presence of apical disease overall. One explanation for the differences in rates of apical periodontitis between males and females, could be that behaviourally, men are more likely to attend the dentist only when symptoms are more severe ( 43 ) and women have been found to be more likely to visit dentists regularly and adhere to advice ( 44 ) which leads to better oral health outcomes( 45 ). The percentage of patients with apical periodontitis in an at least one untreated tooth was 37.8% in the 2008–2009 cohort and 32.4% in the 2018–2019 cohort. This difference was close to statistical significance (p = 0.082). This parameter is not often studied in the literature. The percentage of patients with at least one tooth affected by apical periodontitis regardless of treatment status was 51% in 2008–2009 cohort compared to 44.7% in the 2018–2019 cohort which was significantly different (p = 0.048) These figures overall are similar to those reported in systematic reviews ( 9 , 46 ). The high numbers may be due to chronic apical periodontitis often being asymptomatic ( 47 ), a lack of access to NHS dental care in the UK ( 48 ) and the periapical status of teeth not routinely checked by dentists unless there are symptoms. There was a significant reduction in teeth that had undergone endodontic treatment in the 2018–2019 compared to 2008–2009 cohort (4.2% vs. 5.5%). This reduction is similar to that of a repeated cross-sectional study from Denmark.( 49 ) and indicates a continuation of a trend that was also found in a recent systematic review analysing the prevalence of root filled teeth( 50 ). Treatment quality showed some improvement between cohorts. The percentage of well obturated teeth was 36.2% in cohort 1 compared with 42.4% in cohort 2. A cross sectional study of 136 patients in a deprived area of London found 44.3% of cases having inadequate root fillings in 2012 ( 30 ). The percentage of endodontically treated teeth with apical radiolucencies was similar in both cohorts (27.9% and 29.3%). This non-significant difference is similar to the findings of Razdan et al.( 49 ). In an earlier repeated cross-sectional study in Norway, changes in quality and numbers of endodontically treated teeth with apical periodontitis were not significantly different between 1993 and 2003 ( 42 ). However, the prevalence of root canal treated teeth was lower in the latter cohort in a study from Denmark between 2009 and 2019 ( 51 ). Elsewhere in the literature, the percentage of endodontically treated teeth being associated with apical periodontitis in single cross sectional studies was higher (36%-48% )( 9 , 46 , 52 , 53 ) and was found to be 38.3% in a small study in London ( 30 ). Teeth with suboptimal treatments in both cohorts presented with a significantly higher number of apical radiolucencies than teeth with optimal treatments. Compared to teeth with poor technical quality of root fillings, well obturated teeth have been found to be associated with a lower prevalence of apical periodontitis ( 51 , 54 , 55 ). Interestingly, Frisk et al. did not find that improvements in endodontic quality led to reductions in apical periodontitis associated with root filled teeth ( 56 ). Pooling the data from both groups in this study, the prevalence of apical periodontitis was found to be higher in sub-optimally treated molars compared to sub-optimally treated anterior teeth and premolars. The higher prevalence of apical periodontitis in both suboptimal and well obturated molars compared to other tooth types may be due to molars having more complex anatomy than other teeth. The percentage of well obturated molars is also likely to have been overestimated due to the images of root canals superimposing on one another in multi-rooted teeth. This would result in high proportion of multirooted teeth assigned to the well obturated category incorrectly. The number of root canal treated anterior teeth decreased significantly in cohort 2. This may be due to changes in disease levels or as a result of the changes in dentist renumeration. However, this means that molar teeth represent a larger proportion of the endodontically treated teeth in cohort 2. Since endodontically treated molars with suboptimal treatments have more apical radiolucencies than the other sub-optimally treated teeth groups, this may have counteracted the positive effect of the reduction in suboptimal root canal treatments in the latter cohort resulting in a similar number of endodontically treated teeth with apical periodontitis in the two cohorts. In other words, the persistently high level of post-treatment disease which has been noticed by several authors in similar repeated cross-sectional investigations (Hulsmann 2016), may be explained in the present study, by the fact that more challenging root canal treatments (molars), which are more prone to failure, were carried out in the 2018/19 cohort. The average percentage of individuals with apical periodontitis analysed in this study (cohort 1: 51% and cohort 2: 44.7%, average 47.85%) is lower than most other studies as per a recent systematic review ( 9 ). At a patient level, this review found a prevalence of apical periodontitis of 52%. They are also lower than the average for developed countries (51%). However, in this same review, when studies using panoramic radiographs were looked at alone, an average of 46% of patients having at least one tooth with apical periodontitis was found ( 9 ). The number of patients with apical periodontitis in this study is lower than the number reported in a smaller single cross sectional study undertaken in 2014 with panoramic radiographs in another group of patients in London (49%) ( 30 ). The method of evaluating disease is also relevant. The sensitivity of two dimensional radiography in detecting apical periodontitis is limited by anatomical features (noise) and geometric distortion ( 57 ). Despite this, periapical radiography is considered the standard for the detection of apical periodontitis ( 31 ). Numerous studies have used panoramic radiographs for this purpose and we have attempted to use a classification( 29 ) that is common to many of them. Panoramic radiographs have been shown to be acceptable for the purpose of epidemiological studies ( 58 ) and the development of digital technology may further enhance their usefulness ( 59 ). However, panoramic radiographs are not ideal in detecting the presence of decay in DMFT scoring compared to other intra-oral methods ( 60 , 61 ). It must be acknowledged that for the detection of apical radiolucencies whilst panoramic radiographs have a high specificity, sensitivity is significantly lower than periapical radiographs particularly in the upper molar and incisor regions and for detecting small apical radiolucencies ( 62 , 63 , 64 , 65 ). CBCT scans have an even higher sensitivity compared to periapical radiographs in detecting apical lesions and poor quality root fillings( 66 ). Overall, therefore, the true prevalence of endodontic disease is very likely to be higher whilst the true quality of endodontic treatment is likely to be lower in both cohorts. CONCLUSION In this repeated cross-sectional study of panoramic radiographs from 2008/2009 and 2018/2019, in the latter cohort there was a significant reduction in DMFT scores, a higher proportion of missing teeth relative to decayed and filled teeth, a significant reduction of the number of patients with apical periodontitis, a significant reduction of the number of patients with endodontically treated teeth, a reduction in patients with untreated apical radiolucencies, a lower number of endodontically treated teeth, a lower number of endodontically treated teeth with suboptimal treatments, a significantly lower number of root canal treated anterior teeth and a significantly higher proportion of root canal treated molars. This data suggests a general reduction of caries and endodontic disease burden and some improvement in the apparent quality of endodontic treatments. Changes in dentist renumeration may also account for the increase in missing teeth relative to disease levels in the latter cohort. Declarations CONFLICT OF INTEREST The authors have stated explicitly that there are no conflicts of interest in connection with this article. FUNDING STATEMENT This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. References Kakehashi S, Stanley HR, Fitzgerald RJ. THE EFFECTS OF SURGICAL EXPOSURES OF DENTAL PULPS IN GERM-FREE AND CONVENTIONAL LABORATORY RATS. Oral Surg Oral Med Oral Pathol. 1965;20:340–9. Möller AJ, Fabricius L, Dahlén G, Ohman AE, Heyden G. Influence on periapical tissues of indigenous oral bacteria and necrotic pulp tissue in monkeys. Scand J Dent Res. 1981;89(6):475–84. Nair PNR. 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Socio-economic and health status as a predictor of apical periodontitis in adult patients in Croatia. Oral Diseases. 2019;25(1):300–8. Kielbassa AM, Frank W, Madaus T. Radiologic assessment of quality of root canal fillings and periapical status in an Austrian subpopulation – An observational study. PLOS ONE. 2017;12(5):e0176724. Allihaibi M, Niazi SA, Farzadi S, Austin R, Ideo F, Cotti E, et al. Prevalence of apical periodontitis in patients with autoimmune diseases: A case-control study. International Endodontic Journal. 2023;56(5):573–83. Lukacs JR. Sex differences in dental caries experience: clinical evidence, complex etiology. Clinical Oral Investigations. 2011;15(5):649–56. Shaffer JR, Wang X, McNeil DW, Weyant RJ, Crout R, Marazita ML. Genetic Susceptibility to Dental Caries Differs between the Sexes: A Family-Based Study. Caries Research. 2015;49(2):133–40. Ferraro M, Vieira AR. Explaining Gender Differences in Caries: A Multifactorial Approach to a Multifactorial Disease. International Journal of Dentistry. 2010;2010:649643. Skudutyte-Rysstad R, Eriksen HM. Endodontic status amongst 35-year-old Oslo citizens and changes over a 30-year period. Int Endod J. 2006;39(8):637–42. Kent S, Regan A, McDonald C, Henry A, Dawoud B, Hennedige A, et al. Gender differences in patients with severe dental infections presenting to hospital. British Dental Journal. 2021. Coda Bertea P, Staehelin K, Dratva J, Zemp Stutz E. Female gender is associated with dental care and dental hygiene, but not with complete dentition in the Swiss adult population. Journal of Public Health. 2007;15(5):361–7. Thomson WM, Williams SM, Broadbent JM, Poulton R, Locker D. Long-term Dental Visiting Patterns and Adult Oral Health. Journal of Dental Research. 2010;89(3):307–11. Pak JG, Fayazi S, White SN. Prevalence of Periapical Radiolucency and Root Canal Treatment: A Systematic Review of Cross-sectional Studies. Journal of Endodontics. 2012;38(9):1170–6. Abbott PV. Classification, diagnosis and clinical manifestations of apical periodontitis. Endodontic Topics. 2004;8(1):36–54. Clark SD. Spatial disparities in access to NHS dentistry: a neighbourhood-level analysis in England. European Journal of Public Health. 2024. Razdan A. Trends of endodontic and periapical status in adult Danish populations from 1997 to 2009: A repeated cross-sectional study. International Endodontic Journal. 2021;55:164–76. León-López M, Cabanillas-Balsera D, Martín-González J, Montero-Miralles P, Saúco-Márquez JJ, Segura-Egea JJ. Prevalence of root canal treatment worldwide: A systematic review and meta-analysis. International Endodontic Journal. 2022;55(11):1105–27. Razdan A, Schropp L, Væth M, Kirkevang L-L. Root filled teeth in two parallel Danish cohorts: A repeated longitudinal cohort study. International Endodontic Journal. 2023;56(5):558–72. Jakovljevic A, Nikolic N, Jacimovic J, Pavlovic O, Milicic B, Beljic-Ivanovic K, et al. Prevalence of Apical Periodontitis and Conventional Nonsurgical Root Canal Treatment in General Adult Population: An Updated Systematic Review and Meta-analysis of Cross-sectional Studies Published between 2012 and 2020. Journal of Endodontics. 2020;46(10):1371-86.e8. Sadat Miri S, Khademi A, Amirkhani Z, Amiri SM, Goodarzi M, Khazaei S. Prevalence of Apical Periodontitis in Different Communities: A Meta-Analysis. Iran Endod J. 2018;13(4):438–45. Dugas N, Lawrence H, Teplitsky P, Pharoah M, Friedman S. Periapical health and treatment quality assessment of root-filled teeth in two Canadian populations. International endodontic journal. 2003;36(3):181–92. Frisk F, Hugoson A, Hakeberg M. Technical quality of root fillings and periapical status in root filled teeth in Jönköping, Sweden. Int Endod J. 2008;41(11):958–68. Frisk F, Hugoson A, Hakeberg M. Technical quality of root fillings and periapical status in root filled teeth in Jönköping, Sweden. International Endodontic Journal. 2008;41(11):958–68. Patel S, Dawood A, Mannocci F, Wilson R, Pitt Ford T. Detection of periapical bone defects in human jaws using cone beam computed tomography and intraoral radiography. Int Endod J. 2009;42(6):507–15. Ahlqwist M, Halling A, Hollender L. Rotational panoramic radiography in epidemiological studies of dental health. Comparison between panoramic radiographs and intraoral full mouth surveys. Swed Dent J. 1986;10(1–2):73–84. Izzetti R, Nisi M, Aringhieri G, Crocetti L, Graziani F, Nardi C. Basic Knowledge and New Advances in Panoramic Radiography Imaging Techniques: A Narrative Review on What Dentists and Radiologists Should Know. Applied Sciences. 2021;11. Flint DJ, Paunovich E, Moore WS, Wofford DT, Hermesch CB. A diagnostic comparison of panoramic and intraoral radiographs. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology. 1998;85(6):731–5. Kamburoğlu K, Kolsuz E, Murat S, Yüksel S, Özen T. Proximal caries detection accuracy using intraoral bitewing radiography, extraoral bitewing radiography and panoramic radiography. Dentomaxillofacial Radiology. 2012;41(6):450–9. Estrela C, Bueno MR, Leles CR, Azevedo B, Azevedo JR. Accuracy of cone beam computed tomography and panoramic and periapical radiography for detection of apical periodontitis. Journal of endodontics. 2008;34(3):273–9. Maddalone M, Bonfanti E, Pellegatta A, Citterio CL, Baldoni M. Digital Orthopantomography vs Cone Beam Computed Tomography-Part 1: Detection of Periapical Lesions. J Contemp Dent Pract. 2019;20(5):593–7. Nardi C, Calistri L, Pradella S, Desideri I, Lorini C, Colagrande S. Accuracy of Orthopantomography for Apical Periodontitis without Endodontic Treatment. J Endod. 2017;43(10):1640–6. Nardi C, Calistri L, Grazzini G, Desideri I, Lorini C, Occhipinti M, et al. Is Panoramic Radiography an Accurate Imaging Technique for the Detection of Endodontically Treated Asymptomatic Apical Periodontitis? 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Additional Declarations There is a duality of interest Cite Share Download PDF Status: Published Journal Publication published 14 Aug, 2025 Read the published version in British Dental Journal → Version 1 posted Editorial decision: revise 25 Feb, 2025 Review # 2 received at journal 11 Feb, 2025 Reviewer # 2 agreed at journal 21 Jan, 2025 Review # 1 received at journal 21 Jan, 2025 Reviewer # 1 agreed at journal 21 Jan, 2025 Reviewers invited by journal 21 Jan, 2025 Editor assigned by journal 08 Jan, 2025 Submission checks completed at journal 08 Jan, 2025 First submitted to journal 25 Dec, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5710951","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research","associatedPublications":[],"authors":[{"id":405159773,"identity":"87816ed0-609c-4523-8a52-e587e3b8108e","order_by":0,"name":"Francesco Mannocci","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABEElEQVRIiWNgGAWjYBAC9gYMIWbmwwwMBRAmNi08BzC1sCUzMBiQpIWBxxi/FunDzx78qKiT52fgTvxcuMNGnr+d57PBDwMGef4GHmMDbFr40swNe84cNpzZwLtZeuaZNMMZh3k3J/YYMBjOOMBjnIBFiz0Pg5k0Y9uBBIMDvBukedsOJxgw824+DHQY4wagC7E4m4GHh/2bNOO/OpCWzb8hWngeg7TY49bCA7SlgRmkZRvUFh7mZKCWRJAWbA4DaimT7DkG9Esz7zZr3jaQX9iMDXsMJJKBjGKs3udh3ybxowYYYuy9m2/ztgFDrP/wY4kfFTa2/e3NmyWwhTIcoMWBBI5YGQWjYBSMglFADAAATUpQ9VOPuhIAAAAASUVORK5CYII=","orcid":"","institution":"","correspondingAuthor":true,"prefix":"","firstName":"Francesco","middleName":"","lastName":"Mannocci","suffix":""},{"id":405159774,"identity":"b62ecb3a-0ae4-486f-8456-7889dae799a8","order_by":1,"name":"Chetan morjaria","email":"","orcid":"https://orcid.org/0009-0003-4064-7642","institution":"King's College London","correspondingAuthor":false,"prefix":"","firstName":"Chetan","middleName":"","lastName":"morjaria","suffix":""},{"id":405159775,"identity":"51cd83b8-e420-4ea4-85a6-b948048575c6","order_by":2,"name":"Filippo Cavalli","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Filippo","middleName":"","lastName":"Cavalli","suffix":""}],"badges":[],"createdAt":"2024-12-25 11:40:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5710951/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5710951/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41415-025-8644-0","type":"published","date":"2025-08-15T00:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":74587240,"identity":"204816f2-bb4d-4c3a-8c37-c28932d3bf5b","added_by":"auto","created_at":"2025-01-23 16:55:06","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":45416,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of selection and analysis process.\u003c/p\u003e","description":"","filename":"groupimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5710951/v1/5c1d8aac42dccec88ed5f6a7.jpeg"},{"id":95234072,"identity":"edf4ed7a-cc21-4b95-822e-b5cd076761a7","added_by":"auto","created_at":"2025-11-05 16:54:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":960037,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5710951/v1/2a5f6c88-3e48-4c27-8076-47593010d8aa.pdf"}],"financialInterests":"There is a duality of interest","formattedTitle":"A retrospective repeated cross sectional study assessing changes in the prevalence of apical periodontitis associated with the endodontic status and DMFT scores of patients in two adult cohorts (2008/2009 and 2018/2019) attending a UK dental hospital.","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eApical periodontitis is an inflammatory response of the periapical tissues caused by the presence of microbes within the root canal system of an infected tooth (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Bacteria may enter the pulp space through breaches in the dental hard tissue barrier (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) most commonly due to the carious process, but also through trauma-induced fractures and cracks, tooth surface loss, iatrogenic damage to teeth and periodontal disease.\u003c/p\u003e \u003cp\u003eChanges in the prevalence of apical periodontitis would therefore occur if the causes of microbial ingress were prevented, if teeth affected by apical periodontitis were effectively treated to allow periapical inflammation to resolve and radiographic healing to occur; or if teeth affected by apical periodontitis were extracted.\u003c/p\u003e \u003cp\u003eWhilst endodontic outcome studies have reported success rates of approximately 80\u0026ndash;90% (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e), such studies are generally carried out in secondary care or specialist settings, which account for the minority of endodontic treatments undertaken within the population. This may create problems when translating these outcomes into the general population where the vast majority of endodontic treatments are carried out in general dental practice (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAlthough cross-sectional studies do not provide information on treatment outcome, they do provide insight into the presence of disease (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Repeated cross-sectional studies can analyse trends in disease prevalence (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e) and provide insight into the effectiveness of past public health resource allocation and potential future prevention and treatment strategies(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn radiographic surveys, high levels of apical periodontitis have been reported globally (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). The extent and quality of root canal fillings have also been reviewed as an assessment and prognostic tool(\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). They can act as a crude surrogate method of extrapolating the extent of apical disinfection and entombment of residual bacteria and apical sealing (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFewer studies are available to associate tooth type presence with apical disease levels in cross-sectional studies, despite this being an important potential confounder when assessing the prevelance of apical disease (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Attempts to correlate changes in apical periodontitis with decayed, missing and filled teeth (DMFT) scores are also lacking. It has been found that multiple carious lesions, inadequate coronal restorations and high DMFT scores are risk indicators of apical periodontitis (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e) (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the UK, general dentistry is predominantly carried out in government subsidised NHS dental settings, where the funding structure has been deemed inadequate and not fit for purpose (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e) Furthermore, the problem is accentuated as the UK has an aging population and caries prevalence has been shown to increase with age in every time period (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHowever more positively, in the UK, dental health surveys over 50 years have shown consistent reductions in dental disease by measure of tooth loss and edentulism (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eImprovements in endodontic undergraduate training across dental schools in the UK have been observed (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e) and advances in endodontic techniques such as the developments in nickel-titanium instruments have meant that root canal treatments may be carried out more predictably, especially in less experienced clinician groups (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e)) whilst the barriers to their usage (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e) have also reduced.\u003c/p\u003e \u003cp\u003eTo our knowledge, no repeated cross-sectional study has investigated the association between changes in DMFT, tooth type presence, quality of root canal obturations and prevalence of apical periodontitis.\u003c/p\u003e \u003cp\u003eThe aims of the study are therefore to:\u003c/p\u003e \u003cp\u003e1. Compare from panoramic radiographs, the prevalence of apical periodontitis affecting endodontically treated and non-endodontically treated teeth in patients referred to a British National Health Service (NHS) Hospital in 2008\u0026ndash;2009 (cohort 1) and 2018\u0026ndash;2019 (cohort 2).\u003c/p\u003e \u003cp\u003e2. Compare the quality of endodontic treatments of the two cohorts of patients and assess the association between quality of root canal treatments and radiographic detection of apical disease.\u003c/p\u003e \u003cp\u003e3. Record DMFT scores of the patients to provide comparison between cohorts and associations with the presence of apical periodontitis.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cp\u003eThis retrospective cross-sectional study examined panoramic radiographs from a total of 980 patients, evenly distributed in two time periods: 2008-2009 (490 patients) and 2018-2019 (490 patients).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll panoramic radiographs were obtained from a single centre, \u003cem\u003eanonymised\u003c/em\u003e in \u003cem\u003eanonymized\u003c/em\u003e , which serves a wide geographic area encompassing \u003cem\u003eanonymized\u003c/em\u003e in the UK. The collected radiographs included those taken for any reason in the departments of oral surgery, restorative dentistry, and endodontics.\u003c/p\u003e\n\u003cp\u003eTrained and qualified radiographers used two panoramic radiograph machines (PM-2002-CC, PROMAX or PRO ONE; Planmeca Helsinki, Finland) to capture the radiographs. These radiographs were stored in the hospital database.\u003c/p\u003e\n\u003cp\u003eTo ensure comparability between the cohorts, all patients who had panoramic radiographs within the respective time periods were sorted by age using a radiography software (Planmeca Romexis dental imaging software; Planmeca; Helsinki, Finland). The patients were then divided into seven age groups, and 70 patients from each age group were randomly selected using a random number generator. An overview of the process of radiograph collection is given in Figure 1.\u003c/p\u003e\n\u003cp\u003eTwo calibrated examiners with similar clinical experience independently assessed the collected radiographs. Prior to the study, calibration was conducted using 15 radiographs not included in this research. The examiners used the same examination room, lighting conditions, 15-inch computer screens (Hewlett-Packard, USA), and assessed the radiographs individually at similar times of day. They utilized the same radiographic software and were experienced in digital radiography. They were permitted to adjust magnification, brightness and contrast to optimize detection(25). Any disagreements between the examiners were discussed and resolved through consensus.\u003c/p\u003e\n\u003cp\u003eIf a patient had multiple panoramic radiographs taken within the same year, the first radiograph of acceptable quality was used. Panoramic radiographs were excluded from the study following the criteria reported in table1.The data collected from each panoramic radiograph are reported in table 2.\u003c/p\u003e\n\u003cp\u003eTable 1 Exclusion Criteria\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 601px;\"\u003e\n \u003ch2\u003eExclusion criteria:\u003c/h2\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 601px;\"\u003e\n \u003cp\u003eRadiographs of insufficient diagnostic quality according to existing literature (26)\u0026nbsp;\u003c/p\u003e\n \u003cp\u003ePatients under 18 years old\u003c/p\u003e\n \u003cp\u003eEdentulous patients\u003c/p\u003e\n \u003cp\u003eSectional radiographs\u0026nbsp;\u003c/p\u003e\n \u003cp\u003ePatients in the second cohort (2018-2019) who were already included in the first cohort (2008-2009).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003ch2\u003e\u003cbr\u003e\u003c/h2\u003e\n\u003cp\u003eTable 2 Data Collected\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eParameter measured\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eMethod of collection\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003ePatient age at the time of exposure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003e\u0026nbsp;Calculated from date of exposure of radiograph and patient date of birth information on file\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eSex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eData on file\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eNumber of erupted teeth present\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eFrom panoramic radiograph excluding third molar teeth (0-28)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eNumber of untreated teeth with apical radiolucency\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eFrom panoramic radiograph\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0 to 28)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eNumber of teeth with satisfactory endodontic treatment\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eNumber of teeth with sub-optimal endodontic obturation\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eThe presence of apical radiolucencies in endodontically treated teeth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eFrom panoramic radiograph. Where intra radicular material was present, the tooth was noted as endodontically treated.\u003c/p\u003e\n \u003cp\u003eThe presence of associated apical periodontitis was noted (Y/N)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eWhether either satisfactorily or sub-optimally obturated teeth were associated with periapical lesions\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eFrom panoramic radiograph. Based on criteria below. (satisfactory obturation Y/N or unsatisfactory obturation Y/N)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eThe presence of apical radiolucency in each given patient regardless of the number or treatment status of the teeth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eTotal number of apical radiolucencies per patient. (0-28)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eDMFT scores of each patient\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eFrom panoramic radiograph. Based on World Health Organisation guidelines\u0026nbsp;(27). excluding third molars. Number of teeth decayed, filled and missing noted.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eThe number of molar teeth present\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eFrom panoramic radiograph. Excluding third molars\u003c/p\u003e\n \u003cp\u003e(0 to 8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eThe quality of root canal obturation in different tooth types (anterior, premolar, or molar) and the presence of apical radiolucency associated with those teeth.\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eFrom panoramic radiograph. For each patient, endodontically treated teeth were allocated into one of 6 categories based on 3 tooth types\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(anterior, premolar and molar) and 2 obturation quality sub types (satisfactory /unsatisfactory)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eAs listed in Table 2, the number of erupted teeth in each patient\u0026apos;s radiograph was noted, irrespective of the condition of the tooth crown. The presence of apical disease and the quality of endodontic treatment was measured in a similar manner to previous studies (28, 29, 30) and following ESE guidelines (31).\u003c/p\u003e\n\u003cp\u003eA root was deemed to have apical radiolucency if the periodontal ligament space was twice the width of the lateral periodontal space or a radiolucency in connection with the apical part of the root was present (32). For multi-rooted teeth, if any root displayed any of these radiographic signs, the tooth was classified as having apical periodontitis.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;A tooth was considered endodontically treated if radiopaque material was visible in the pulp chamber and/or root canals.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eObturation was deemed to be satisfactory if the following criteria were met for all roots of a tooth\u0026nbsp;(28, 29, 30) and ESE guidelines (31):\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003eRoot canal filling material should reach within approximately 2 mm of the radiographic apex of the tooth, the distance from the apex was approximately measured using the measuring tool available in the Romexis software.\u003c/li\u003e\n \u003cli\u003eWithout obvious extrusion beyond the apex\u003c/li\u003e\n \u003cli\u003eThe root canal filling should be free of voids or gaps.\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eIf any of the above criteria were not met, the obturation was recorded as unsatisfactory.\u003c/p\u003e\n\u003cp\u003eBecause of the use of only retrospective fully anonymised data, this study was a non-intervention clinical trial, adopting a standardised non-experimental protocol, GERRI Oversite Committee ethical approval was obtained (Rec Reference: 20/EM/0112). The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist and statement were followed.\u003c/p\u003e\n\u003ch2\u003eData Management\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003eAll the information was transferred to a secure Excel spreadsheet. Data were analysed using SPSS software version 15 (version 15; SPSS Inc.). The statistical analysis consisted of a description of categorical variables (absolute and relative frequencies) and continuous variables (mean, standard deviation, median and range) for the total sample and differentiation by groups.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSample size calculation \u0026amp; statistical analysis\u003c/p\u003e\n\u003cp\u003eA sample size of 980 patients (490/490) provides a maximum error of 4.43% in order to estimate the true AP prevalence in each one of both populations, assuming p=q=50% and confidence 95%.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMoreover, we reach 95.1% of power to detect AP rates at 20% and 30% as significantly different in both groups using a logistic regression model and assuming a confidence level of 95%.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAt patient-level, a simple binary logistic regression model was conducted to assess the relationship between prevalence of AP and group. Odds ratio (OR) and 95% confidence intervals were obtained. Then, logistic models were adjusted by gender and age, and adjusted OR were obtained.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eChi\u003csup\u003e2\u003c/sup\u003e and independent t-test were performed to assess the homogeneity of cohorts by sex and age and significance of DMFT data.\u003c/p\u003e\n\u003cp\u003eAt tooth-level, a multi-level logistic regression using generalized estimation equations (GEE) was conducted to assess the risk of AP in a tooth by the \u0026nbsp;previously mentioned factors. Adjusted odds ratio and 95% confidence intervals were obtained from the Wald\u0026acute;s Chi\u003csup\u003e2\u003c/sup\u003e statistic. Similar linear models using GEE approach were estimated to analyze dependent variables as number of teeth under a specific condition. Beta coefficients and 95% confidence intervals were obtained.\u003c/p\u003e\n\u003cp\u003eThe significance level used in analysis was set at 5% (\u0026alpha;=0.05).\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe sample included 980 Panoramic radiographs from 980 different patients divided into two cohorts, Cohort 1: \u003cem\u003e2008-2009\u0026nbsp;\u003c/em\u003e(n=490)\u003cem\u003e\u0026nbsp;\u003c/em\u003eand Cohort 2\u003cem\u003e: 2018-2019\u003c/em\u003e (n=490).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere were 434 male (44.3%) and 546 female (55.7%), averaging 52.4 years of age. A total of 22,623 teeth were analyzed.\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003ePatient level analysis\u003c/h2\u003e\n\u003ch2\u003ePrevalence of apical radiolucencies\u003c/h2\u003e\n\u003cp\u003eOut of 490 patients, 250 (51%) of patients had at least one tooth with apical disease in Cohort 1 compared to 219 (44.7%) in Cohort 2. There was a statistically significant difference in the percentage of patients with apical radiolucencies between groups (p=0.04 95% CI 0.59-0.98)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Patients in cohort 2 had on average 0.16 fewer teeth affected by apical periodontitis than patients in cohort 1 and a 22% reduced risk of AP (OR=0.78; 95% CI: 0.60-0.99).\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003eApical radiolucencies in untreated teeth\u003c/h2\u003e\n\u003cp\u003eIn cohort 1, 37.8% of patients (185 out of 490) had an apical radiolucency in at least one untreated tooth. In comparison, 32.4% of patients (159 out of 490) in cohort 2 had an apical radiolucency in at least one untreated tooth, the difference was not significant (OR=0.79; 95%CI: 0.61-1.03; p=0.082).\u003c/p\u003e\n\u003ch2\u003eEndodontic treatment\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003e236 patients had at least one endodontically treated tooth in cohort 1, compared with 202 in cohort 2. This reduction was significant (95% CI: -0.5 - - .05, p=0.015).\u003c/p\u003e\n\u003cp\u003eOn average, patients had 0.28 fewer endodontically treated teeth in the latter cohort.\u003c/p\u003e\n\u003cp\u003eThere was no difference between genders in the number of endodontic treatments for either cohort, though both cohorts showed a statistically significant increase in the number of endodontically treated teeth with age (p\u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003eNumber of teeth present and DMFT scores\u003c/h2\u003e\n\u003cp\u003eThe number of teeth present was not significantly different between patients of the two cohorts (p=0.212). 11,173 erupted teeth were present in the 490 patients analyzed in the 2008-2009 cohort whilst 11,451 erupted teeth were present in the 490 patients analyzed in the 2018-2019 cohort.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere was no significant difference (p=0.522) between the mean number of molars per patient (5.01 in cohort 1 vs 5.12 in cohort 2).\u003c/p\u003e\n\u003cp\u003eSignificant differences between decayed, missing and filled teeth scores were found between cohorts (p\u0026lt;0.001). Patients from cohort 1 had a mean DMFT of 15.28, whereas in 2018 this was reduced to 12.81. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe significant difference in DMFT scores but similarity in number of teeth and number molar teeth is indicative of a difference in decayed and filled teeth.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAn analysis of decayed and filled teeth (\u0026lsquo;DFT\u0026rsquo;) was undertaken by removing the number of missing teeth from the DMFT score. The average DFT score in cohort 1 was 9.3 and in cohort 2 it was 7.53. The results showed a significant difference in DFT scores (p\u0026lt;0.001).\u003c/p\u003e\n\u003ch3\u003eNumber of Molar teeth and Apical periodontitis\u003c/h3\u003e\n\u003cp\u003ePatients who had apical periodontitis across the two cohorts had a statistically significant lower number of molar teeth present (p\u0026lt;0.001). However, statistical significance was not found when comparing the difference in the number of molar teeth present in patients with apical periodontitis (p=0.269) or without apical periodontitis (p=0.502)\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003eGender, age and apical periodontitis\u003c/h2\u003e\n\u003cp\u003eIn cohort 1, there were 215 males (43.9%) and 275 females (55.7%). In Cohort 2, there were 219 males (44.7%) and 271 females (55.3%). The groups were homogeneous with regards to this variable (p=0.797).\u003c/p\u003e\n\u003cp\u003eOverall, age and gender had a significant impact on the risk of apical periodontitis. Each additional year implied an increase in risk of apical periodontitis by 1.5% (p=0.001) or 0.006 more teeth (p=0.01). The increase in prevalence of apical periodontitis with age was also evident for both cohorts analyzed individually (p=0.0005). Females had a 27% lower risk of apical periodontitis compared to males (p=0.014) or 0.29 fewer teeth affected by apical periodontitis (p=0.003), this difference prevalence was statistically significant in Cohort 1only (p=0.009) and not in Cohort 2 (p=0.193).\u003c/p\u003e\n\u003ch3\u003eDMFT and Number of Molars by Age group and Gender\u003c/h3\u003e\n\u003cp\u003eIn both cohorts individually and overall, there were significant differences between DMFT scores by age decade and number of molars by age decade. (p\u0026lt;0.001,). DMFT scores increased as the age of the patients increased whilst the number of molars reduced.\u003c/p\u003e\n\u003cp\u003eHowever, by gender the samples did not show significant differences in DMFT scores or number of molars.\u003c/p\u003e\n\u003ch3\u003eDMFT and apical periodontitis\u003c/h3\u003e\n\u003cp\u003eDMFT scores were significantly higher in patients affected by apical periodontitis overall and in both individual cohorts (p\u0026lt;0.001).\u003c/p\u003e\n\u003cp\u003eTable 3 DMFT scores in patients with AP in both cohorts\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eCohort 1\u003c/p\u003e\n \u003cp\u003e(2008/2009)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eCohort 2\u003c/p\u003e\n \u003cp\u003e(2018/2019)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eP Value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003eMean DMFT score in patients without AP\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e12.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e10.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eP\u0026lt;0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003eMean DMFT score in patients with AP\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e18.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e15.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eP\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eA significant association (p\u0026lt;0.001) between DMFT scores and apical radiolucencies in untreated teeth could also be made in the overall sample and in both cohorts individually. Similarly, there was an association between the number of Molar teeth and the presence of apical \u0026nbsp;radiolucencies in the overall sample and in \u0026nbsp;both cohorts individually Patients who had apical periodontitis had a statistically significant lower number of molar teeth present (p\u0026lt;0.001).\u003c/p\u003e\n\u003ch1\u003eTooth level analysis\u003c/h1\u003e\n\u003ch2\u003eNumber of Teeth:\u003c/h2\u003e\n\u003cp\u003eIn cohort 1, 11,172 teeth were analyzed. In cohort 2, 11,451 teeth were analyzed. The groups were homogeneous (p=0.212).\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003ePrevalence of apical radiolucencies in untreated teeth\u003c/h2\u003e\n\u003cp\u003eThe prevalence of apical radiolucencies was not significantly different between cohorts. \u0026nbsp;3.4% of untreated teeth showed apical disease in cohort 1 and 2.9% in cohort 2 (p=0.98).\u003c/p\u003e\n\u003ch2\u003ePrevalence of endodontic treatments\u003c/h2\u003e\n\u003cp\u003eThere was a significant difference in the number of teeth which were endodontically treated with 611 teeth (5.5%) being endodontically treated in cohort 1 whilst 476 (4.2%) were treated in cohort 2 (95% CI: 0.60-0.92, p=0.007). This equates to a 25% lower chance of a tooth having endodontic treatment in 2018/2019 compared to 2008/2009\u0026nbsp;\u003c/p\u003e\n\u003ch3\u003eEndodontic treatment and apical radiolucencies\u003c/h3\u003e\n\u003cp\u003eThough there was a difference in the number of endodontic treatments, the percentage of root treated teeth presenting with apical radiolucencies did not show any significant difference (p=0.772). \u0026nbsp;179 of the 611 (29.3%) of the endodontically treated teeth had apical periodontitis in Cohort 1 compared to 133 of 476 (27.9%) in cohort 2.\u003c/p\u003e\n\u003ch2\u003eDifferences in endodontically treated tooth types between cohorts\u003c/h2\u003e\n\u003cp\u003e126 anterior teeth were treated in cohort 2 which was significantly lower compared to the 227 treated in cohort 1 (p\u0026lt;0.001). The number of premolar and molar teeth treated was however similar. However, it was noted that whilst the numbers appeared to be similar, since there was a difference in the number of endodontically treated teeth for each cohort, when the proportion of endodontically treated teeth for each tooth type was calculated, a significant increase of the proportion of root canal treated molars became evident (cohort 1: 20.2%, cohort 2: 28.7%; p=0.003). \u0026nbsp;as shown in table 7.\u003c/p\u003e\n\u003ch2\u003eQuality of endodontic treatment\u003c/h2\u003e\n\u003cp\u003eThe overall percentage of suboptimal obturated teeth was 63.7%, in cohort 1 whilst it was 57.6% in cohort 2.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere was a 32% higher chance of a satisfactory obturation in cohort 2 compared to cohort 1 (OR=1.32; 95%CI: 0.98-1.78). 389 (63.7%) of teeth were unsatisfactorily obturated in cohort 1 compared with 274 (57.6%) in cohort 2, However, this was short of significance for both obturation qualities (p=0.072).\u003c/p\u003e\n\u003ch3\u003eQuality of endodontic treatment and apical periodontitis\u0026nbsp;\u003c/h3\u003e\n\u003cp\u003eThere was no difference in the prevalence of apical periodontitis in satisfactory (p=0.598) and unsatisfactory obturations between cohorts (p=0.405).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn both cohorts there was a significantly lower prevalence of apical periodontitis in well obturated teeth compared to teeth with suboptimal obturations (cohort 1: 18.9% vs 34.2%, cohort 2 16.3% vs36.9%)\u0026nbsp;(P \u0026lt;0.001).\u003c/p\u003e\n\u003ch2\u003eAnalysis of endodontically treated teeth\u003c/h2\u003e\n\u003ch3\u003eQuality of treatment by tooth type\u003c/h3\u003e\n\u003cp\u003eAlthough there were improvements in quality of obturation for each tooth type in cohort 2 (2018-2019), the differences did not reach statistical significance However, a close to significant difference between molar teeth in cohort 1 and cohort 2 was reached (p=0.061).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;The prevalence of apical periodontitis was examined in both satisfactorily and unsatisfactorily obturated teeth and broken down by tooth type. However, for each tooth type in the same quality subgroup, there was no difference between cohorts.\u003c/p\u003e\n\u003cp\u003eAssessing quality, there were significant differences between tooth types when the data for the two cohorts was combined. Anterior teeth had the lowest percentage of unsatisfactory obturations (45.3%) followed by premolars (60%) and finally molars (73.3%) (P \u0026lt;0.001).\u003c/p\u003e\n\u003ch3\u003eApical periodontitis in endodontically treated teeth\u003c/h3\u003e\n\u003cp\u003eWhen cohorts were combined, endodontically treated premolars had the lowest percentage of apical periodontitis (20.3%), followed by anterior teeth (29.9%) and lastly molar teeth (34.9%). This was significantly lower than the anterior and molar groups (p\u0026lt;0.001). 28.4% of endodontically treated anterior teeth had apical periodontitis compared with 34.9% of Molar teeth, however this difference was not statistically significant (p=0.20).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWhere treatment was suboptimal, the rate of apical periodontitis in premolar (26.9%) and anterior teeth (37.7%) was significantly different (p=0.023). However, the prevalence of apical periodontitis in sub-optimally endodontically treated molar teeth (41.1%) was significantly greater than premolar teeth (p=0.002) but not significantly different than that of anterior teeth.\u003c/p\u003e\n\u003cp\u003eWhere treatment was satisfactory, there were significant differences between tooth types (p=0.015). The prevalence of apical periodontitis was higher in anterior teeth (23.4%) compared with premolar teeth (10.3%) (p=0.004). However, well obturated molar teeth had apical periodontitis in 19.1% of cases which was similar to anterior teeth, but just below statistical significance compared to premolars (p=0.061).\u003c/p\u003e\n\u003cp\u003eTable 7 Numbers and proportions of endodontically treated teeth by tooth type for each cohort\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"554\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCohort 1 (2008/2009)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCohort 2\u003c/p\u003e\n \u003cp\u003e(2018/2019)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eP Value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAnterior teeth as a proportion of endodontically treated teeth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e37.2%\u003c/p\u003e\n \u003cp\u003e(227 teeth)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26.5%\u003c/p\u003e\n \u003cp\u003e(126 teeth)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePremolar teeth as a proportion of endodontically treated teeth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e32.6%\u003c/p\u003e\n \u003cp\u003e(199 teeth)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e34.9%\u003c/p\u003e\n \u003cp\u003e(166 teeth)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.426\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMolar teeth as a proportion of endodontically treated teeth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e30.2%\u003c/p\u003e\n \u003cp\u003e(185 teeth)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e38.7%\u003c/p\u003e\n \u003cp\u003e(184 teeth)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003ch3\u003eQuality of Obturation in different tooth types\u003c/h3\u003e\n\u003cp\u003eTable 8 Comparison of quality of endodontic treatment for each tooth type\u003c/p\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"569\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 242px;\"\u003e\n \u003cp\u003eCohort 1 (2008/2009)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 242px;\"\u003e\n \u003cp\u003eCohort 2 (2018/2019)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eSatisfactorily\u003c/p\u003e\n \u003cp\u003eObturated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 131px;\"\u003e\n \u003cp\u003eUnsatisfactorily\u003c/p\u003e\n \u003cp\u003eObturated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eSatisfactorily\u003c/p\u003e\n \u003cp\u003eObturated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 131px;\"\u003e\n \u003cp\u003eUnsatisfactorily\u003c/p\u003e\n \u003cp\u003eObturated\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eAnterior teeth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003e81 (51.9%)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 131px;\"\u003e\n \u003cp\u003e75 (48 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003e56 (60.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 131px;\"\u003e\n \u003cp\u003e37 (39.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003ePremolar teeth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003e59 (39%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 131px;\"\u003e\n \u003cp\u003e92 (60.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003e57 (46.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 131px;\"\u003e\n \u003cp\u003e66 (53.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eMolar teeth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003e31 (23.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 131px;\"\u003e\n \u003cp\u003e101 (76.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003e46 (35.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 131px;\"\u003e\n \u003cp\u003e85 (64.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eIn this repeated cross-sectional study of panoramic radiographs from 2008/2009 and 2018/2019, we found in the latter cohort a significant reduction in DMFT scores, a significant reduction of the number of patients with apical periodontitis, a significant reduction of the number of patients with endodontically treated teeth, a reduction in patients with untreated teeth with apical periodontitis, a lower number of endodontically treated teeth, a lower number of endodontically treated teeth with suboptimal treatments, a significantly lower number of root canal treated anterior teeth and a significantly higher proportion of root canal treated molars.\u003c/p\u003e \u003cp\u003eThis data suggests a general reduction of caries and endodontic disease burden and a general improvement in the apparent quality of endodontic treatments in this hospital adult patient population.\u003c/p\u003e \u003cp\u003eTypically, patients are referred to any one of the dental specialities within the hospital from primary dental care settings for specialist assessment or treatment where required. However, in most cases, the majority of the dental treatment that patients have had, have been from primary dental care settings outside the hospital, such as NHS general dental practices. During the periods of interest, most panoramic radiographs would have been carried out for UK residents, however we cannot make the assumption that this population is representative of the general population of UK.\u003c/p\u003e \u003cp\u003eWhilst our results did find a significant reduction in DMFT scores over time, this was largely due a significant reduction in filled and decayed teeth as the average number of teeth per patient was similar in both cohorts. This suggests that patients in 2018/2019 have a higher proportion of missing teeth compared to the number of decayed and filled teeth. This could be a result of more extractions and reduced complex restorative work being carried out relative to their disease levels, as a result of the implementation of the new NHS contract in 2006 (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e). Renumeration has been shown to affect treatment delivery (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e). The new contract changed the way general dentists are renumerated from a fee per item model to being paid a fee based upon the band in which the treatment carried out fell into. The model paid dentists based on the highest banded treatment type and did not consider the quantity of treatment provided, and so a single filling or extraction would attract the same fee as multiple fillings and root canal treatments. It is likely that dentists attempted to hit their contract targets in the most efficient way possible, i.e. shifting towards treatments where rewards are high relative to costs and time such as extractions, as opposed to selecting on the basis of clinical factors (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e). An alternative reasoning for the lower number of decayed and filled teeth relative to missing teeth in the second cohort may be because of recent improvements in caries rates at an individual level. This would result in individuals experiencing less decay and having fewer restorations placed whilst the number of missing teeth remaining similar to cohort 1 may be as a result of higher caries experience and intervention which led to a higher number of extractions from the more distant past.\u003c/p\u003e \u003cp\u003eThere was a significant association between age group and DMFT score and apical periodontitis prevalence. For each additional year there was a 1.5% increase in apical periodontitis.\u003c/p\u003e \u003cp\u003eSome studies have recorded an association of age and higher level of dental caries, however, the last UK adult dental health survey (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e) found that younger patients had a higher levels of dental caries than older patients, though older patients had more restorations. Given that levels of apical periodontitis increased with age, this could indicate that it is not necessarily the presence of caries, which is a risk factor, but previous caries experience, which leads to deeper restorations and secondary lesions, which more quickly affect the pulp tissue. The association of older age with an increased likelihood of detecting apical periodontitis has been reported in a number of other studies (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e) (\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThough DMFT scores were higher in older age groups, there was no difference in either DMFT scores or number of teeth by gender. However, there was a significantly lower number of teeth with apical pathology (27%) in female patients compared to males. Assessing individual cohorts, this significant difference was present in cohort 1, however the difference was not significant in cohort 2. The adult dental health survey found increased caries experience in males (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). Interestingly, other studies from different populations have found decreased caries experience in males (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e), though the cause of this is likely to be multifactorial(\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA corelation between DMFT scores and the presence of apical periodontitis (\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e) has been shown and the data from this study supports this. A clear association is seen between DMFT scores, the number of missing molar teeth, the presence of untreated apical disease and the presence of apical disease overall.\u003c/p\u003e \u003cp\u003eOne explanation for the differences in rates of apical periodontitis between males and females, could be that behaviourally, men are more likely to attend the dentist only when symptoms are more severe (\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e) and women have been found to be more likely to visit dentists regularly and adhere to advice (\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e) which leads to better oral health outcomes(\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe percentage of patients with apical periodontitis in an at least one untreated tooth was 37.8% in the 2008\u0026ndash;2009 cohort and 32.4% in the 2018\u0026ndash;2019 cohort. This difference was close to statistical significance (p\u0026thinsp;=\u0026thinsp;0.082). This parameter is not often studied in the literature. The percentage of patients with at least one tooth affected by apical periodontitis regardless of treatment status was 51% in 2008\u0026ndash;2009 cohort compared to 44.7% in the 2018\u0026ndash;2019 cohort which was significantly different (p\u0026thinsp;=\u0026thinsp;0.048) These figures overall are similar to those reported in systematic reviews (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e). The high numbers may be due to chronic apical periodontitis often being asymptomatic (\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e), a lack of access to NHS dental care in the UK (\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e) and the periapical status of teeth not routinely checked by dentists unless there are symptoms.\u003c/p\u003e \u003cp\u003eThere was a significant reduction in teeth that had undergone endodontic treatment in the 2018\u0026ndash;2019 compared to 2008\u0026ndash;2009 cohort (4.2% vs. 5.5%). This reduction is similar to that of a repeated cross-sectional study from Denmark.(\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e) and indicates a continuation of a trend that was also found in a recent systematic review analysing the prevalence of root filled teeth(\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTreatment quality showed some improvement between cohorts. The percentage of well obturated teeth was 36.2% in cohort 1 compared with 42.4% in cohort 2. A cross sectional study of 136 patients in a deprived area of London found 44.3% of cases having inadequate root fillings in 2012 (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe percentage of endodontically treated teeth with apical radiolucencies was similar in both cohorts (27.9% and 29.3%). This non-significant difference is similar to the findings of Razdan et al.(\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e). In an earlier repeated cross-sectional study in Norway, changes in quality and numbers of endodontically treated teeth with apical periodontitis were not significantly different between 1993 and 2003 (\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e). However, the prevalence of root canal treated teeth was lower in the latter cohort in a study from Denmark between 2009 and 2019 (\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e). Elsewhere in the literature, the percentage of endodontically treated teeth being associated with apical periodontitis in single cross sectional studies was higher (36%-48% )(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e) and was found to be 38.3% in a small study in London (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTeeth with suboptimal treatments in both cohorts presented with a significantly higher number of apical radiolucencies than teeth with optimal treatments. Compared to teeth with poor technical quality of root fillings, well obturated teeth have been found to be associated with a lower prevalence of apical periodontitis (\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eInterestingly, Frisk et al. did not find that improvements in endodontic quality led to reductions in apical periodontitis associated with root filled teeth (\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePooling the data from both groups in this study, the prevalence of apical periodontitis was found to be higher in sub-optimally treated molars compared to sub-optimally treated anterior teeth and premolars.\u003c/p\u003e \u003cp\u003eThe higher prevalence of apical periodontitis in both suboptimal and well obturated molars compared to other tooth types may be due to molars having more complex anatomy than other teeth. The percentage of well obturated molars is also likely to have been overestimated due to the images of root canals superimposing on one another in multi-rooted teeth. This would result in high proportion of multirooted teeth assigned to the well obturated category incorrectly.\u003c/p\u003e \u003cp\u003eThe number of root canal treated anterior teeth decreased significantly in cohort 2. This may be due to changes in disease levels or as a result of the changes in dentist renumeration. However, this means that molar teeth represent a larger proportion of the endodontically treated teeth in cohort 2. Since endodontically treated molars with suboptimal treatments have more apical radiolucencies than the other sub-optimally treated teeth groups, this may have counteracted the positive effect of the reduction in suboptimal root canal treatments in the latter cohort resulting in a similar number of endodontically treated teeth with apical periodontitis in the two cohorts.\u003c/p\u003e \u003cp\u003eIn other words, the persistently high level of post-treatment disease which has been noticed by several authors in similar repeated cross-sectional investigations (Hulsmann 2016), may be explained in the present study, by the fact that more challenging root canal treatments (molars), which are more prone to failure, were carried out in the 2018/19 cohort.\u003c/p\u003e \u003cp\u003eThe average percentage of individuals with apical periodontitis analysed in this study (cohort 1: 51% and cohort 2: 44.7%, average 47.85%) is lower than most other studies as per a recent systematic review (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). At a patient level, this review found a prevalence of apical periodontitis of 52%. They are also lower than the average for developed countries (51%). However, in this same review, when studies using panoramic radiographs were looked at alone, an average of 46% of patients having at least one tooth with apical periodontitis was found (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). The number of patients with apical periodontitis in this study is lower than the number reported in a smaller single cross sectional study undertaken in 2014 with panoramic radiographs in another group of patients in London (49%) (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe method of evaluating disease is also relevant. The sensitivity of two dimensional radiography in detecting apical periodontitis is limited by anatomical features (noise) and geometric distortion (\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e). Despite this, periapical radiography is considered the standard for the detection of apical periodontitis (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eNumerous studies have used panoramic radiographs for this purpose and we have attempted to use a classification(\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e) that is common to many of them. Panoramic radiographs have been shown to be acceptable for the purpose of epidemiological studies (\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e) and the development of digital technology may further enhance their usefulness (\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e). However, panoramic radiographs are not ideal in detecting the presence of decay in DMFT scoring compared to other intra-oral methods (\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e). It must be acknowledged that for the detection of apical radiolucencies whilst panoramic radiographs have a high specificity, sensitivity is significantly lower than periapical radiographs particularly in the upper molar and incisor regions and for detecting small apical radiolucencies (\u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e, \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e, \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e). CBCT scans have an even higher sensitivity compared to periapical radiographs in detecting apical lesions and poor quality root fillings(\u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e). Overall, therefore, the true prevalence of endodontic disease is very likely to be higher whilst the true quality of endodontic treatment is likely to be lower in both cohorts.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eIn this repeated cross-sectional study of panoramic radiographs from 2008/2009 and 2018/2019, in the latter cohort there was a significant reduction in DMFT scores, a higher proportion of missing teeth relative to decayed and filled teeth, a significant reduction of the number of patients with apical periodontitis, a significant reduction of the number of patients with endodontically treated teeth, a reduction in patients with untreated apical radiolucencies, a lower number of endodontically treated teeth, a lower number of endodontically treated teeth with suboptimal treatments, a significantly lower number of root canal treated anterior teeth and a significantly higher proportion of root canal treated molars.\u003c/p\u003e \u003cp\u003eThis data suggests a general reduction of caries and endodontic disease burden and some improvement in the apparent quality of endodontic treatments. Changes in dentist renumeration may also account for the increase in missing teeth relative to disease levels in the latter cohort.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCONFLICT OF INTEREST\u003c/h2\u003e \u003cp\u003eThe authors have stated explicitly that there are no conflicts of interest in connection with this article.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFUNDING STATEMENT\u003c/h2\u003e \u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKakehashi S, Stanley HR, Fitzgerald RJ. THE EFFECTS OF SURGICAL EXPOSURES OF DENTAL PULPS IN GERM-FREE AND CONVENTIONAL LABORATORY RATS. 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International Endodontic Journal. 2021;55:164\u0026ndash;76.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLe\u0026oacute;n-L\u0026oacute;pez M, Cabanillas-Balsera D, Mart\u0026iacute;n-Gonz\u0026aacute;lez J, Montero-Miralles P, Sa\u0026uacute;co-M\u0026aacute;rquez JJ, Segura-Egea JJ. Prevalence of root canal treatment worldwide: A systematic review and meta-analysis. International Endodontic Journal. 2022;55(11):1105\u0026ndash;27.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRazdan A, Schropp L, V\u0026aelig;th M, Kirkevang L-L. Root filled teeth in two parallel Danish cohorts: A repeated longitudinal cohort study. International Endodontic Journal. 2023;56(5):558\u0026ndash;72.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJakovljevic A, Nikolic N, Jacimovic J, Pavlovic O, Milicic B, Beljic-Ivanovic K, et al. Prevalence of Apical Periodontitis and Conventional Nonsurgical Root Canal Treatment in General Adult Population: An Updated Systematic Review and Meta-analysis of Cross-sectional Studies Published between 2012 and 2020. Journal of Endodontics. 2020;46(10):1371-86.e8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSadat Miri S, Khademi A, Amirkhani Z, Amiri SM, Goodarzi M, Khazaei S. Prevalence of Apical Periodontitis in Different Communities: A Meta-Analysis. Iran Endod J. 2018;13(4):438\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDugas N, Lawrence H, Teplitsky P, Pharoah M, Friedman S. Periapical health and treatment quality assessment of root-filled teeth in two Canadian populations. International endodontic journal. 2003;36(3):181\u0026ndash;92.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrisk F, Hugoson A, Hakeberg M. Technical quality of root fillings and periapical status in root filled teeth in J\u0026ouml;nk\u0026ouml;ping, Sweden. Int Endod J. 2008;41(11):958\u0026ndash;68.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrisk F, Hugoson A, Hakeberg M. Technical quality of root fillings and periapical status in root filled teeth in J\u0026ouml;nk\u0026ouml;ping, Sweden. International Endodontic Journal. 2008;41(11):958\u0026ndash;68.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatel S, Dawood A, Mannocci F, Wilson R, Pitt Ford T. Detection of periapical bone defects in human jaws using cone beam computed tomography and intraoral radiography. Int Endod J. 2009;42(6):507\u0026ndash;15.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAhlqwist M, Halling A, Hollender L. Rotational panoramic radiography in epidemiological studies of dental health. Comparison between panoramic radiographs and intraoral full mouth surveys. Swed Dent J. 1986;10(1\u0026ndash;2):73\u0026ndash;84.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIzzetti R, Nisi M, Aringhieri G, Crocetti L, Graziani F, Nardi C. Basic Knowledge and New Advances in Panoramic Radiography Imaging Techniques: A Narrative Review on What Dentists and Radiologists Should Know. Applied Sciences. 2021;11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFlint DJ, Paunovich E, Moore WS, Wofford DT, Hermesch CB. A diagnostic comparison of panoramic and intraoral radiographs. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology. 1998;85(6):731\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKamburoğlu K, Kolsuz E, Murat S, Y\u0026uuml;ksel S, \u0026Ouml;zen T. Proximal caries detection accuracy using intraoral bitewing radiography, extraoral bitewing radiography and panoramic radiography. Dentomaxillofacial Radiology. 2012;41(6):450\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEstrela C, Bueno MR, Leles CR, Azevedo B, Azevedo JR. Accuracy of cone beam computed tomography and panoramic and periapical radiography for detection of apical periodontitis. Journal of endodontics. 2008;34(3):273\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaddalone M, Bonfanti E, Pellegatta A, Citterio CL, Baldoni M. Digital Orthopantomography vs Cone Beam Computed Tomography-Part 1: Detection of Periapical Lesions. J Contemp Dent Pract. 2019;20(5):593\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNardi C, Calistri L, Pradella S, Desideri I, Lorini C, Colagrande S. Accuracy of Orthopantomography for Apical Periodontitis without Endodontic Treatment. J Endod. 2017;43(10):1640\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNardi C, Calistri L, Grazzini G, Desideri I, Lorini C, Occhipinti M, et al. Is Panoramic Radiography an Accurate Imaging Technique for the Detection of Endodontically Treated Asymptomatic Apical Periodontitis? J Endod. 2018;44(10):1500\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiang Y-H, Li G, Wesselink PR, Wu M-K. Endodontic outcome predictors identified with periapical radiographs and cone-beam computed tomography scans. Journal of endodontics. 2011;37(3):326\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"british-dental-journal","isNatureJournal":false,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"bdj","sideBox":"Learn more about [British Dental Journal](http://www.nature.com/bdj/)","snPcode":"41415","submissionUrl":"https://mts-bdj.nature.com/cgi-bin/main.plex","title":"British Dental Journal","twitterHandle":"@the_bdj","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5710951/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5710951/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eAim:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo compare the prevalence of apical periodontitis (AP), endodontic treatments, quality of endodontic treatments and their association with apical radiolucencies and DMFT scores, in patients attending a British National Health Service (NHS) Hospital in 2008-2009 (Cohort 1/C1) and 2018-2019 (Cohort 2/C2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethodology\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRandomly selected panoramic radiographs of 980 patients, evenly distributed into two cohorts: C1 (2008-2009) and C2 (2018-2019), were retrospectively analysed.\u003c/p\u003e\n\u003cp\u003ePatient demographics, number of teeth, presence and quality of endodontic treatments, apical radiolucencies in treated and untreated teeth, endodontic treatment quality, apical periodontitis prevalence by tooth type and DMFT scores were compared.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e C1 had significantly higher DMFT scores (p\u0026lt;0.001), but similar numbers of teeth to C2. Patients with apical periodontitis had higher DMFT scores and lower number of molars (p\u0026lt;0.001). Similar percentages of untreated teeth had apical periodontitis in C1 (3.4%) and C2 (2.9%) but at a patient level, C2 had significantly fewer endodontic treatments (48.2% vs 41.2%; p=0.015), less apical disease (51%, vs 44%; p=0.04) and fewer endodontically treated teeth (5.5% vs 4.2%; p=0.007). The percentage of endodontically treated teeth with apical periodontitis was similar (29.3%, vs 27.9%). C2 patients had less unsatisfactorily obturated teeth (63.7% vs 57.6%) which was short of significance (p=0.072).\u003c/p\u003e\n\u003cp\u003eC2 had fewer endodontically treated anterior teeth (p\u0026lt;0.001) but a higher proportion of endodontically treated molars (20.2%, vs 28.7%; p=0.003). A close to significant improvement in the quality of molars’ root canal treatments in C2 was noted (well-obturated teeth C1: 23.48%, c2: 35.11%; p=0.061).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA reduction of caries and endodontic disease burden and a slight improvement in the quality of endodontic treatments in the 2018/2019 cohort was observed. This was not accompanied by increased tooth retention.\u003c/p\u003e","manuscriptTitle":"A retrospective repeated cross sectional study assessing changes in the prevalence of apical periodontitis associated with the endodontic status and DMFT scores of patients in two adult cohorts (2008/2009 and 2018/2019) attending a UK dental hospital.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-23 16:47:01","doi":"10.21203/rs.3.rs-5710951/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"revise","date":"2025-02-25T18:31:43+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"This content is not available.","date":"2025-02-11T12:27:37+00:00","index":2,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2025-01-21T16:32:18+00:00","index":2,"fulltext":"This content is not available."},{"type":"editorInvitedReview","content":"This content is not available.","date":"2025-01-21T15:43:29+00:00","index":1,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2025-01-21T15:15:37+00:00","index":1,"fulltext":"This content is not available."},{"type":"reviewersInvited","content":"","date":"2025-01-21T14:20:33+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-01-08T11:55:31+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-01-08T11:55:25+00:00","index":"","fulltext":""},{"type":"submitted","content":"British Dental Journal","date":"2024-12-25T11:37:18+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"british-dental-journal","isNatureJournal":false,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"bdj","sideBox":"Learn more about [British Dental Journal](http://www.nature.com/bdj/)","snPcode":"41415","submissionUrl":"https://mts-bdj.nature.com/cgi-bin/main.plex","title":"British Dental Journal","twitterHandle":"@the_bdj","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"3c1adf9e-faad-4cd1-9182-2574b0ee1f65","owner":[],"postedDate":"January 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":43197941,"name":"Health sciences/Health care/Dentistry/Dental public health/Dental epidemiology"},{"id":43197942,"name":"Health sciences/Health care/Dentistry/Endodontics/Root canal treatment"}],"tags":[],"updatedAt":"2025-11-05T16:53:54+00:00","versionOfRecord":{"articleIdentity":"rs-5710951","link":"https://doi.org/10.1038/s41415-025-8644-0","journal":{"identity":"british-dental-journal","isVorOnly":false,"title":"British Dental Journal"},"publishedOn":"2025-08-15 00:00:00","publishedOnDateReadable":"August 15th, 2025"},"versionCreatedAt":"2025-01-23 16:47:01","video":"","vorDoi":"10.1038/s41415-025-8644-0","vorDoiUrl":"https://doi.org/10.1038/s41415-025-8644-0","workflowStages":[]},"version":"v1","identity":"rs-5710951","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5710951","identity":"rs-5710951","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}