Multifactorial analysis of factors influencing premolar mobility in stage III/IV grade C periodontitis patients ≤35 years of age: A cross-sectional study

Multifactorial analysis of factors influencing premolar mobility in stage III/IV grade C periodontitis patients ≤35 years of age: A cross-sectional study | 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 Article Multifactorial analysis of factors influencing premolar mobility in stage III/IV grade C periodontitis patients ≤35 years of age: A cross-sectional study Jia-Ming Li, Xian-E Wang, Xiao Xu, Jian Liu, Li Zhang, Xiang-Hui Feng, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4635163/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Oct, 2024 Read the published version in BMC Oral Health → Version 1 posted 10 You are reading this latest preprint version Abstract Background: Previous studies has revealed a potential association between crown-root ratio and root morphology in patients with mild chronic periodontitis, suggesting a possible link to tooth mobility. However, further comprehensive analytical investigations were not pursued. Our previous study observed that 76% of aggressive periodontitis patients exhibit abnormal root morphology, especially in premolars, associated with severe alveolar bone loss and mobility, leading to poor clinical outcomes. This study aims to investigate the specific correlations between factors such as alveolar bone resorption, root morphology, crown-root ratio, and periodontal clinical indicators with tooth mobility of premolars in stage III/IV grade C periodontitis patients ≤35 years of age. Materials and methods: A total of 1064 premolars from 151 stage III/IV grade C periodontitis patients ≤35 years of age were recruited. Clinical periodontal parameters and radiographic parameters were recorded. Logistic regression analysis was employed to investigate the relationships between these indicators and tooth mobility. Results: The difference in the length of the premolar roots wassignificant, ranging from 6.80 mm-20.96 mm. Teeth with shorter roots (mean root length of 10.22 mm) exhibitedgrade I mobility with only 28% alveolar bone resorption, while the percentages ofmedium-length roots (mean root length of 12.67 mm) and longer roots(average of 14.91 mm) exhibiting alveolar bone resorptionwere 34% and 37%, respectively. In terms of classifying the degree of mobility, multiple regression models incorporating the crown-root ratio at the bone level, average probing depth and root length demonstrated optimal performance (P<0.001, AIC=1700.574). Conclusion: Premolar mobility is associated with variations in root length, alveolar bone resorption, and probing depth. The crown-root ratio at the bone level can effectively serve as a predictor for assessing tooth mobility when there are discrepancies in root length and extent of alveolar bone resorption. tooth mobility stage III/IV grade C periodontitis alveolar bone resorption tooth root morphology multifactorial analysis Figures Figure 1 Background Mobility represents the extent of tooth movement in response to external forces and serves as a crucial clinical indicator for assessing periodontal disease severity, predicting tooth prognosis, and formulating treatment strategies. In a comprehensive study on patients with periodontitis, Chun-Teh Lee et al. employed machine learning techniques to identify predictive factors associated with tooth loss, revealing mobility as a significant predictor of tooth loss (number of teeth with mobility degree 1, OR = 1.831, P = 0.001; number of teeth with mobility degree 2/3, OR = 1.210, P < 0.001) (Lee et al., 2023 ). According to a retrospective study on aggressive periodontitis, teeth with a degree of mobility of 1 exhibited a 4.71-fold greater risk of tooth loss than nonmobile teeth, while those with a degree of mobility of 2 had a 6.12-fold greater risk, and those with a degree of mobility of 3 had a 16.7-fold greater risk(Shi et al., 2020 ). Therefore, investigating the etiological factors of tooth mobility has significant clinical implications for tooth prognosis. Previous research has demonstrated a correlation between tooth mobility and systemic or local factors, including periodontitis, trauma, occlusal trauma, periapical inflammation, and systemic hormone administration(Giargia & Lindhe, 1997 ; Muhlemann, 1969 ). The primary cause of increased tooth mobility resulting from periodontal disease is a reduction in periodontal supporting tissues due to junctional epithelium migration and alveolar bone resorption(Ericsson & Lindhe, 1984 ; Persson & Svensson, 1980 ). However, at present, there is a lack of precise data establishing a direct correlation between the extent of alveolar bone resorption and tooth mobility. Furthermore, crown-root ratio (CRR) imbalance and root morphology can influence plant mobility. W. Schulte et al. revealed a potential association between the CRR and root morphology in patients with mild chronic periodontitis, suggesting a possible link to tooth mobility. However, further comprehensive analytical investigations were not pursued(Schulte et al., 1992 ). Aggressive periodontitis (AgP) is a rapidly progressive form of periodontal disease characterized by significant resorption of alveolar bone and tooth mobility in patients who are typically younger than 35 years and are diagnosed with stage III/IV grade C periodontitis according to the 2018 classification(Tonetti et al., 2018 ). Our previous research, based on periapical radiographs, revealed that 76% of individuals diagnosed with AgP (136/179 patients) exhibited abnormal root morphology, with a higher prevalence observed in premolars(Xu et al., 2009 ). Patients with AgP often present with issues such as a disproportionate CRR, characterized by short roots and tapered roots resulting in reduced root surface area. These clinical manifestations are accompanied by severe alveolar bone resorption and abnormal tooth mobility, ultimately leading to a poor prognosis or even premature tooth loss. This significantly impacts patients’ overall quality of life (Lu et al., 2017 ; Qiao et al., 2013 ; Xu et al., 2010 ). Therefore, it is imperative to devote attention to the comprehensive analysis of factors influencing mobility in premolars among AgP patients. This study aimed to investigate the specific correlations between factors such as alveolar bone resorption, root morphology, the CRR, and periodontal clinical indicators and the tooth mobility of premolars in stage III/IV Grade C periodontitis patients ≤ 35 years of age. Materials and Methods Patient population A total of 151 AgP patients were enrolled in the periodontal Department of Peking University School and Hospital of Stomatology between 2001 and 2015. The diagnosis of AgP was based on the following clinical and radiographic criteria proposed by the 1999 International World Workshop for a Classification of Periodontal Diseases and Conditions(Lang N, 1999). The inclusion criteria were as follows: 1) ≤35 years old; 2) at least 20 remaining teeth in the mouth; 3) At least 6 teeth have a probing depth ≥5 mm and attachment loss of ≥3 mm on adjacent surfaces; 4) Non-smokers. These patients were diagnosed with stage III/IV grade C periodontitis according to the 2018 classification. Before diagnosis and treatment, full-mouth periapical radiographs of all subjects were taken by radiology technicians. The study was approved by the Ethics Committee of PKUSS (approval number: PKUSSIIT02305). Clinical examinations All clinical data, including the following indicators, were obtained through repeated measurements by two experienced clinical physicians (Li Xu and Li Zhang): probing depth (PD), bleeding index (BI), and tooth mobility (TM). The average PD (APD) was determined by calculating the mean value of six measurement points for PD. Similarly, the average BI (ABI) was obtained by averaging measurements taken on both the buccal and lingual sides for the BI. The degree of tooth mobility is assessed using handheld dental examination forceps, and it is determined based on the direction and magnitude: if there is solely buccolingual movement, it is classified as degree 1; if there is movement in both the buccolingual and mesiodistal directions, it is classified as degree 2; and if vertical mobility occurs, it is classified as degree 3(Newman et al., 2015). Furthermore, considering the magnitude of tooth displacement, adjustments are made according to the principle of severity: tooth displacement less than 1 mm corresponds to degree 1, tooth displacement between 1-2 mm corresponds to degree 2, and tooth displacement exceeding 2 mm corresponds to degree 3(Lindhe et al., 2015). Radiographic analyses All periapical radiographs were confirmed to have an appropriate exposure time and suitable projection angle by experienced radiological technologists and clinical doctors, and the inclusion criteria for periapical radiographs were as follows: (1) Radiographs should be accurately captured, ensuring precise positioning of the teeth at the center of the image and complete visibility of the entire tooth structure within the image boundaries; (2) The image exhibits distinct clarity, with evident contrast in the photograph; (3) The projection angle is appropriate, with the vertical angle accurately aligned and the length of the teeth closely approximating their actual measurements; (4) The interproximal structure of the teeth appears well defined and intact, exhibiting correct horizontal angles, no apparent overlap with adjacent structures, and an absence of caries, fillings, restorations or rotations; (5) No abnormalities were detected in the periodontal ligament space (widening or disappearance), periodontal-pulp complex lesions, or residual roots. All included radiographic images were scanned for digital documentation (UMAX Powerlook1000 manual control, 600 dpi) and measured using GeoGebra (Classic 5.0.735.0-d, International GeoGebra Institute, Linz, Austria) by one researcher (Jia-Ming Li). Measurement of periapical radiographs 1. Confirm point: Set point on the mesial and distal marginal ridge of crown (A, B); enamel-dentin junctions (C, D) situated mesial and distal; root apex point (G); and alveolar crest points (E, F) positioned mesial and distal to the target teeth. The reference for alveolar ridge point confirmation is based on the research conducted by Schulte et al (Schulte et al., 1992). 2. Confirm the tooth axis: Researchers set the tooth axis by dividing the crown into two parts, based on the area below the marginal ridge of the crown and approximately two-thirds of the root crown surface, both mesial and distal. The varying degrees of curvature of the apical third can be disregarded when determining the tooth axis; thus, it is not necessary for the apical point to intersect with or pass through the tooth axis. 3. Measure crown-to-root ratio (CRR): Connect the mesial and distal central CEJs (C, D), and draw parallel lines passing through the mesial and distal marginal ridge points (A, B), respectively, intersecting the long axis of the tooth at two points (H, I). The midpoint between these two points was selected as the crown point (J). A line parallel to the CEJ passing through the root apex point (G), intersecting the long axis of the tooth at one point considered a hypothetical root apex point (K), was drawn. The JL along the CEJ was measured as the crown length from J to K, which represents the root length. The ratio of crown length to root length is defined as JL/KL. 4. The parameter of root width (PRW) was measured according to the methodology proposed by Xu Li et al(Xu et al., 2009). According to the research of Liu et al., root width can be categorized into two types, namely, normal and cone roots, based on a threshold ratio of 0.37 between the surface area of the root collar and that below the ridge top(Liu et al., 2022); 5. Measure the extent of alveolar bone resorption: Construct parallel lines to the CEJ passing through points E and F at varying distances from the alveolar crest. These lines intersect the long axis of the tooth at two distinct points (R and Q). The linear distance between these points (RK) and the hypothetical root apex (QK) was measured. The average bone loss ratio (ABLR) was 1-. 6. Bone level crown-root ratio (B-CRR): B-CRR= (CRR+ ABLR)/(1- ABLR). This indicator can be utilized to estimate the remaining volume of periodontal membrane tissue and the lever arm magnitude during tooth loading, thereby partially reflecting the resistance torque generated by teeth when subjected to external forces. The measurement method used is depicted in Fig. 1. Statistical methods The statistical significance tests in this study were conducted using two-tailed tests, with a criterion of P<0.05 to determine significance. Different statistical analysis methods were chosen based on the type of data (categorical or continuous). The statistical analysis was performed using R 4.2.3 software [GUI 1.79 (8198 High Sierra build), S. Urbanek & H.-J. Bibiko, © R Foundation for Statistical Computing, 2021]. The analysis methods included t tests, chi-square tests, nonparametric tests, and logistic regression analysis. For continuous data, normality testing was initially conducted to assess distribution characteristics. Normally distributed continuous data are presented as the mean ± standard deviation (x̄±s), while nonnormally distributed continuous data are presented as the median and interquartile range [M(P_25~P_75)]. Categorical data are expressed as rates or proportions. Paired t tests or analysis of variance (ANOVA) methods were employed for normally distributed continuous data; however, for nonnormally distributed variables such as the crown–root ratio and reference values for root width, either transformation techniques to achieve a normal distribution or nonparametric tests were utilized instead. Chi-square tests or similar approaches were used for categorical data. Multiple factor analysis was performed to identify factors influencing tooth mobility. Tooth mobility served as the dependent variable (with control=I), which had more than two levels and passed the parallelism test with a result of P<0.05; therefore, an unordered multinomial logistic regression analysis was applied. A backwards selection method was implemented to select variables and establish the optimal model that provides odds ratios (ORs) along with their corresponding 95% confidence intervals for relevant variables. Results A total of 1064 premolars from 151 stage III/IV grade C periodontitis patients ≤35 years of age were recruited. A total of 72 males and 79 females (mean age: 29.32 ± 3.06 years) were enrolled in this study. Among these, 286 maxillary first premolars (26.88%), 286 maxillary second premolars (26.88%), 236 mandibular first premolars (22.18%), and 256 mandibular second premolars (24.06%) were included. The numbers of mobile premolars with degrees 0, I, II and III were 213, 458, 300 and 93, respectively. The average root length of the 1064 premolars was 12.60 ±2.13 mm, with a range of 6.80-20.96 mm. Root length was considered a continuous variable, and these teeth were equally categorized into three groups based on their root length: short, medium, and long roots. The mean root lengths for these groups were 10.22±1.12 mm, 12.67±0.54 mm, and 14.91±2.13 mm, respectively, exhibiting an approximate difference of 2 mm between each group's mean values. The average crown lengths were similar among the three groups (5.12±0.67 mm, 5.07±0.78 mm, and 5.07±0.77 mm, P=0.515). However, when comparing the CRRs across the three groups, statistically significant differences were detected (0.51±0.09 for the short root group, 0.40±0.07 for the medium root group, 0.34±0.05 for the long root group, P=0.000). The mean values of the PRW in the three groups were 0.56±0.23 mm, 0.57±0.63 mm, and 0.58±0.55 mm, respectively, with no statistically significant differences observed (P=0.830). When the degree of tooth mobility was the same, significant variations in alveolar bone resorption were observed among the three groups with short, medium, and long roots. The average alveolar bone absorption for each group at grade I mobility was 0.28 ± 0.15 for the short root group, 0.34 ± 0.14 for the medium root group, and 0.37 ± 0.13 for the long root group (P=0.000). When the degree of tooth mobility was the same, there were no statistically significant differences in the B-CRR among the short-, medium- and long-root groups. The 95% confidence intervals for the B-CRRs of premolars with mobility grades of 0, I, II, and III were 0.68, 0.74, 1.07, 1.16, 1.43, 1.59, and 2.13, 2.89, respectively (Table 1). The APD, ABI, root length, crown length, CRR, ABLR, maximum BLR, and B-CRR exhibited significant variations among the different degrees of tooth mobility (Table 2). Multilevel logistic regression model for factors influencing premolar mobility Based on the results of univariate analysis, a multilevel logistic regression model was developed to classify tooth mobility into four categories (0, I, II, III), incorporating the following key indicators: ABLR, maximum BLR, and B-CRR. Due to their lower retention rate in clinical practice (often leading to extraction), teeth with Grade III mobility were underrepresented. Consequently, for consideration purposes, the model merged teeth with grade II and III mobility. The regression results are presented in Table 3. The three multiple-level logistic regression models all showed significant differences (P<0.001). Model 3 had the lowest AIC (1700.574) and residual (1676.574), indicating the best performance. At a significance level of α=0.05, compared to teeth with mobility degree I as a reference, teeth with no mobility degree 0 showed significant differences in APD (P<0.001, OR=0.681), root length (P<0.05, OR=1.142), and B-CRR (P<0.001, OR=0.017). There were also significant differences in the APD (P<0.001, OR=1.581) and B-CRR (P<0.05, OR=0.824) between teeth with mobility degrees II and III. Discussion In this study, we investigated the factors influencing the tooth mobility of premolars in stage III/IV grade C periodontitis patients ≤35 years of age. First, significant variations in the length of the roots of premolars, ranging from 6.80 mm to 20.96 mm, were detected, while no difference in crown length was detected. Therefore, our findings suggested that the CRR is primarily determined by root length, which aligns with previous research conducted by our team 8 . At the same time, the long-root group exhibited greater alveolar bone resorption than both the medium-root and short-root groups. Consequently, it can be inferred that shorter roots are more prone to experiencing and displaying increased mobility when alveolar bone resorption is equal. Teeth with shorter roots (with an average root length of approximately 10.22 mm) can exhibit grade I mobility with an ABLR of only 28%, while teeth with medium roots (with an average root length of approximately 12.67 mm) can experience grade I mobility with an ABLR of 34%. On the other hand, teeth with longer roots (with an average root length of approximately 14.91 mm) display grade I mobility only when the ABLR is 37%. This finding effectively elucidates why teeth with shorter roots tend to become mobile. Therefore, it is evident that assessing the prognosis of teeth solely based on BL%/age without considering root length lacks rigor. Therefore, if the degree of tooth mobility is primarily estimated by ABLR, it necessitates adjustment based on root length. This study revealed no significant difference in the B-CRR among the three groups with short, medium, and long roots under equivalent degrees of mobility. This implies that the B-CRR remains unaffected by the absolute root length and can more effectively differentiate degrees of mobility. In essence, irrespective of varying levels of alveolar bone absorption and differing root lengths, tooth mobility can be roughly assessed based on the B-CRR without further modification. The B-CRR threshold values for grade I, II, and III mobility are 1, 1.3, and 1.9, respectively. When the B-CRR reaches or exceeds 1, it indicates grade I mobility; when it reaches or exceeds 1.9, it indicates grade III mobility. Based on clinical experience corroborated for the first time through specific numerical values in this study, tooth mobility occurs when the B-CRR is approximately equal to 1. Therefore, in the future, dentists or big data analysis could preliminarily estimate tooth mobility based on the B-CRR; however, if there is a substantial discrepancy between tooth mobility and the B-CRR, then occlusal factors or other non-periodontitis-related alveolar bone loss should be considered. Additionally, caution should be exercised when considering treatment plans such as crown elongation or orthodontic movement for premolars when the B-CRR reaches 1. The mobility of teeth under external forces is the result of rotational movement caused by mechanical forces applied to the teeth. The factors influencing tooth mobility can be categorized into three aspects: external force (dynamic force), resistance, and dynamic and resistance arms. During functional loading (chewing), occlusal forces primarily contribute to the external forces experienced by teeth. In this study, external force refers to a stable and appropriately sized force applied by researchers on the dental crown during clinical examination. Resistance primarily arises from the deformation of nonrigid periodontal tissues, which is intricately linked to the volume (surface area and width), composition, and structure of the periodontal ligament(Storey, 1973). When the root is short, tapered, or single, its periodontal ligament has a relatively reduced surface area. Consequently, given an equivalent degree of alveolar bone absorption, it becomes more susceptible to mobility. The width of the periodontal ligament space is closely correlated with changes in tissue structure and occlusal force(Denes et al., 2013; Nanci & Bosshardt, 2006; Niver et al., 2011). The present study excluded teeth with widened or narrowed periodontal ligament space on periapical films to minimize the potential influence of abnormal periodontal ligament width on tooth mobility. In addition, the presence of inflammation in the periodontium leads to an increase in mobility due to a decrease in collagen fibres, an increase in blood vessels, pathological alterations in fibroblasts, and disruption of the structure and alignment of the main fibres within the periodontal ligament(Attstrom, 1970; Goellner et al., 2013b; Zoellner & Hunter, 1994). This results in diminished resistance provided by the periodontal tissues. The present study further validated the association between periodontal inflammation (PD, BI, etc.) and tooth mobility. The center of resistance represents the point at which the combined forces acting on teeth achieve equilibrium, thereby reflecting factors such as root morphology and the degree of alveolar bone resorption. In this study, we utilized the B-CRR to estimate resistance and determine the center of resistance, providing a more comprehensive assessment of the influential factors affecting tooth mobility. Furthermore, our model demonstrated that the B-CRR serves as an optimal variable for evaluating tooth mobility. For nearly four decades, since the advent of electronic mechanical instruments such as Periotest for quantifying tooth mobility, some studies have employed these devices to objectively measure tooth mobility. However, due to inherent design limitations, these devices primarily assess unidirectional mobility (buccolingual or axial) with a maximum displacement of ≤2 mm, rendering them suitable only for evaluating mild alveolar bone resorption in anterior teeth(Andresen et al., 2003; Goellner et al., 2013a; Muhlemann, 1967; Schulte, 1988; Schulte et al., 1992). Consequently, for teeth in the posterior area with moderate or severe periodontal destruction and exhibiting multidirectional movement or displacement ≥2 mm, comprehensive evaluations of the factors influencing mobility are lacking. The Periotest value (PTV) did not exhibit any significant correlation with the clinically measured displacement of teeth(Goellner et al., 2012). Therefore, the present study used the common approach of assessing tooth mobility using handheld dental forceps and categorizing it into various degrees according to its direction and displacement. There are certain limitations in this study. The regression model results demonstrated a significant association between root length and tooth mobility, while no significant relationship was observed between root width and tooth mobility. However, it should be noted that the evaluation of buccolingual conditions not captured in the assessment of apical films was not considered, indicating some limitations in the evaluation process(Liu et al., 2022). There are also several other limitations, including the inclusion of a small number of grade III mobile teeth in the study, the evaluation of root and alveolar bone conditions through two-dimensional periapical films, and the restriction to premolars. Although three-dimensional CBCT currently offers advantages in observing root and alveolar bone, promoting the use of periapical films as the most widely used imaging examination in clinical practice is warranted. This study has significant clinical value and merits further research, such as expanding to incisors and molars, proposing the establishment of databases and large medical services for building models, and utilizing artificial intelligence to enhance the accuracy and reliability of prediction models for clinical application, ultimately benefiting patients. Conclusion This study provides preliminary evidence that tooth mobility in patients with AgP is associated with the crown-root ratio, level of alveolar bone resorption, and probing depth of premolars. The bone-level crown-root ratio effectively predicts tooth mobility at different root lengths and levels of alveolar bone resorption, offering clinicians valuable insights for assessing factors contributing to tooth mobility and making prognosis judgments for teeth with varying root lengths. Moreover, this study lays the foundation for future applications of big data artificial intelligence in rapidly estimating tooth mobility based on periapical radiographs. Declarations Ethics approval and consent to participate This study was approved by the Peking University Ethics Committee and Competent Authority (No. PKUSSIRB-202495004). Consent was obtained from all participants in this study. All patients in our hospital will sign informed consent before receiving oral treatment, which includes that the patient's medical records can be used for teaching and research. This study was performed in accordance with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Consent for publication Not applicable. Availability of data and materials The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. The datasets generated and/or analysed during the current study are not publicly available due patient imaging data is a matter of personal privacy. Competing interests The authors declare that they have no competing interests. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Authors’ contributions Jia-Ming Li, Xian-E Wang, Li Xu and Huan-Xin Meng conceived and presented this study. Jia-Ming Li, Xian-E Wang wrote the main manuscript text and prepared figures and tables. Xiao Xu and Jian Liu offered help with imaging measurements. Li Zhang, Xiang-Hui Feng and Rui-Fang Lu were responsible for collecting clinical data. All authors reviewed the manuscript. References Andresen, M., Mackie, I., & Worthington, H. (2003). The Periotest in traumatology. Part I. Does it have the properties necessary for use as a clinical device and can the measurements be interpreted? 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J Periodontal Res , 46 (6), 730-741. https://doi.org/10.1111/j.1600-0765.2011.01396.x Persson, R., & Svensson, A. (1980). Assessment of tooth mobility using small loads. I. Technical devices and calculations of tooth mobility in periodontal health and disease. J Clin Periodontol , 7 (4), 259-275. https://doi.org/10.1111/j.1600-051x.1980.tb01969.x Qiao, M., Xu, L., Meng, H. X., Tian, Y., Zhang, L., & Feng, X. H. (2013). [Alveolar bone loss in nuclear families of aggressive periodontitis and the heredity of root shape]. Zhonghua Kou Qiang Yi Xue Za Zhi , 48 (10), 577-580. https://www.ncbi.nlm.nih.gov/pubmed/24438562 Schulte, W. (1988). The new Periotest method. Compend Suppl (12), S410-415, S417. https://www.ncbi.nlm.nih.gov/pubmed/3271598 Schulte, W., d'Hoedt, B., Lukas, D., Maunz, M., & Steppeler, M. (1992). Periotest for measuring periodontal characteristics--correlation with periodontal bone loss. J Periodontal Res , 27 (3), 184-190. https://doi.org/10.1111/j.1600-0765.1992.tb01667.x Shi, S., Meng, Y., Li, W., Jiao, J., Meng, H., & Feng, X. (2020). A nomogram prediction for mandibular molar survival in Chinese patients with periodontitis: A 10-year retrospective cohort study. J Clin Periodontol , 47 (9), 1121-1131. https://doi.org/10.1111/jcpe.13343 Storey, E. (1973). The nature of tooth movement. Am J Orthod , 63 (3), 292-314. https://doi.org/10.1016/0002-9416(73)90353-9 Tonetti, M. S., Greenwell, H., & Kornman, K. S. (2018). Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. J Clin Periodontol , 45 Suppl 20 , S149-S161. https://doi.org/10.1111/jcpe.12945 Xu, L., Meng, H. X., Tian, Y., Zhang, L., Feng, X. H., & Zhang, G. (2009). [Evaluation of root abnormity in patients with aggressive periodontitis]. Zhonghua Kou Qiang Yi Xue Za Zhi , 44 (5), 266-269. https://www.ncbi.nlm.nih.gov/pubmed/19575981 Xu, L., Meng, H. X., Zhang, L., Feng, X. H., Shi, D., & Tian, Y. (2010). [Analysis of alveolar bone loss and related factors in patients with aggressive periodontitis]. Zhonghua Kou Qiang Yi Xue Za Zhi , 45 (12), 745-748. https://www.ncbi.nlm.nih.gov/pubmed/21211242 Zoellner, H., & Hunter, N. (1994). The Vascular-Response in Chronic Periodontitis. Australian Dental Journal , 39 (2), 93-97. https://doi.org/DOI 10.1111/j.1834-7819.1994.tb01380.x Tables Tables 1 to 3 are available in the Supplementary Files section Additional Declarations No competing interests reported. Supplementary Files Tables.docx Cite Share Download PDF Status: Published Journal Publication published 16 Oct, 2024 Read the published version in BMC Oral Health → Version 1 posted Editorial decision: Revision requested 09 Sep, 2024 Reviews received at journal 07 Sep, 2024 Reviewers agreed at journal 25 Aug, 2024 Reviews received at journal 08 Aug, 2024 Reviewers agreed at journal 17 Jul, 2024 Reviewers invited by journal 04 Jul, 2024 Editor invited by journal 02 Jul, 2024 Editor assigned by journal 30 Jun, 2024 Submission checks completed at journal 30 Jun, 2024 First submitted to journal 25 Jun, 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-4635163","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":329743427,"identity":"dff53f81-36d3-4199-9e7c-c158709e5d0f","order_by":0,"name":"Jia-Ming Li","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Jia-Ming","middleName":"","lastName":"Li","suffix":""},{"id":329743428,"identity":"dd6d9e1d-79c4-4f47-8593-227e53c26259","order_by":1,"name":"Xian-E Wang","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Xian-E","middleName":"","lastName":"Wang","suffix":""},{"id":329743429,"identity":"cb1f5ca2-97a7-4ea9-97bf-986bc325ea97","order_by":2,"name":"Xiao Xu","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Xiao","middleName":"","lastName":"Xu","suffix":""},{"id":329743430,"identity":"2acc693a-d252-4f54-ad53-08495f6c1074","order_by":3,"name":"Jian Liu","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Jian","middleName":"","lastName":"Liu","suffix":""},{"id":329743431,"identity":"e0b0fb1c-0434-4bd9-9e25-0b2af96b05a0","order_by":4,"name":"Li Zhang","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"Zhang","suffix":""},{"id":329743432,"identity":"3d9089b1-4759-4135-b04a-ba103d704fac","order_by":5,"name":"Xiang-Hui Feng","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Xiang-Hui","middleName":"","lastName":"Feng","suffix":""},{"id":329743433,"identity":"2160a89f-864a-4400-be1b-16f8dc5beafa","order_by":6,"name":"Rui-Fang Lu","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Rui-Fang","middleName":"","lastName":"Lu","suffix":""},{"id":329743434,"identity":"336e61a3-2702-45c4-8f23-ff5349847fab","order_by":7,"name":"Li Xu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAwUlEQVRIiWNgGAWjYFAC5obDIIqfvfnwAyK1MEK0SPYcSzMA0hJEaWEGUQY3chQkiNJicCOx8XBBxTY54wM5DAaMO2zqCGqRnJHYcHjGmdvGZgfOHnjAeCaNsC38EkAtvG23E7cd7EswYGw7TFgLG1RL/eZmHgMJxrb/xNuSYMAG1nKAsBbJnocNh3nO3DaccYYtzSCxLVmygZAWg+PJhz/zVNyW55//+PCDj212/ARtQQUJJKofBaNgFIyCUYADAADPF0Bo0POcqQAAAABJRU5ErkJggg==","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":true,"prefix":"","firstName":"Li","middleName":"","lastName":"Xu","suffix":""},{"id":329743435,"identity":"b1754501-11ea-4a19-9075-55bbb6e112f8","order_by":8,"name":"Huan-Xin Meng","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Huan-Xin","middleName":"","lastName":"Meng","suffix":""}],"badges":[],"createdAt":"2024-06-25 09:18:34","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4635163/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4635163/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12903-024-05039-2","type":"published","date":"2024-10-16T15:57:44+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":60912347,"identity":"503ac077-dadc-4d47-8b70-8697a3c1d703","added_by":"auto","created_at":"2024-07-23 13:01:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2590139,"visible":true,"origin":"","legend":"\u003cp\u003eApproaches for the analysis of image data. Points A and B are the mesial and distal points of the marginal ridge of the crown, respectively. Points C and D are the mesial and distal points of the central CEJ, respectively. Point G is the root apex. Points E and F are the mesial and distal alveolar crests, respectively. Connect the mesial and distal central CEJ points (C, D), and draw parallel lines passing through the mesial and distal marginal ridge points (A, B), respectively, intersecting the long axis of the tooth at two points (H, I). J is the midpoint of H and I. Draw a line parallel to the CEJ passing through the root apex point (G), intersecting the long axis of the tooth at one point considered the hypothetical root apex point (K). M and N are the midpoints of CK and DK, respectively. Aline was drawn through the MN, which intersects the root outline at points O and P. Lines were constructed parallel to the CEJ,passing through points E and F, respectively, at varying distances from the alveolar crest. These lines intersect the long axis of the tooth at two distinct points (R and Q).\u003c/p\u003e","description":"","filename":"Figure.png","url":"https://assets-eu.researchsquare.com/files/rs-4635163/v1/12ee171335ed98a5803f0db9.png"},{"id":67149738,"identity":"d5ea011f-905f-4091-b862-75d1fbcb881a","added_by":"auto","created_at":"2024-10-21 16:13:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3297793,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4635163/v1/b7be1331-a7ce-44a7-bdc7-c20feda3a0ce.pdf"},{"id":60912349,"identity":"8f6d742e-5043-4d02-af31-4be3af50dff4","added_by":"auto","created_at":"2024-07-23 13:01:39","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":25024,"visible":true,"origin":"","legend":"","description":"","filename":"Tables.docx","url":"https://assets-eu.researchsquare.com/files/rs-4635163/v1/46557b14d0de4e53fef8309a.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Multifactorial analysis of factors influencing premolar mobility in stage III/IV grade C periodontitis patients ≤35 years of age: A cross-sectional study","fulltext":[{"header":"Background","content":"\u003cp\u003eMobility represents the extent of tooth movement in response to external forces and serves as a crucial clinical indicator for assessing periodontal disease severity, predicting tooth prognosis, and formulating treatment strategies. In a comprehensive study on patients with periodontitis, Chun-Teh Lee et al. employed machine learning techniques to identify predictive factors associated with tooth loss, revealing mobility as a significant predictor of tooth loss (number of teeth with mobility degree 1, OR\u0026thinsp;=\u0026thinsp;1.831, P\u0026thinsp;=\u0026thinsp;0.001; number of teeth with mobility degree 2/3, OR\u0026thinsp;=\u0026thinsp;1.210, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Lee et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). According to a retrospective study on aggressive periodontitis, teeth with a degree of mobility of 1 exhibited a 4.71-fold greater risk of tooth loss than nonmobile teeth, while those with a degree of mobility of 2 had a 6.12-fold greater risk, and those with a degree of mobility of 3 had a 16.7-fold greater risk(Shi et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Therefore, investigating the etiological factors of tooth mobility has significant clinical implications for tooth prognosis. Previous research has demonstrated a correlation between tooth mobility and systemic or local factors, including periodontitis, trauma, occlusal trauma, periapical inflammation, and systemic hormone administration(Giargia \u0026amp; Lindhe, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Muhlemann, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1969\u003c/span\u003e). The primary cause of increased tooth mobility resulting from periodontal disease is a reduction in periodontal supporting tissues due to junctional epithelium migration and alveolar bone resorption(Ericsson \u0026amp; Lindhe, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1984\u003c/span\u003e; Persson \u0026amp; Svensson, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e1980\u003c/span\u003e). However, at present, there is a lack of precise data establishing a direct correlation between the extent of alveolar bone resorption and tooth mobility. Furthermore, crown-root ratio (CRR) imbalance and root morphology can influence plant mobility. W. Schulte et al. revealed a potential association between the CRR and root morphology in patients with mild chronic periodontitis, suggesting a possible link to tooth mobility. However, further comprehensive analytical investigations were not pursued(Schulte et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1992\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAggressive periodontitis (AgP) is a rapidly progressive form of periodontal disease characterized by significant resorption of alveolar bone and tooth mobility in patients who are typically younger than 35 years and are diagnosed with stage III/IV grade C periodontitis according to the 2018 classification(Tonetti et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Our previous research, based on periapical radiographs, revealed that 76% of individuals diagnosed with AgP (136/179 patients) exhibited abnormal root morphology, with a higher prevalence observed in premolars(Xu et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Patients with AgP often present with issues such as a disproportionate CRR, characterized by short roots and tapered roots resulting in reduced root surface area. These clinical manifestations are accompanied by severe alveolar bone resorption and abnormal tooth mobility, ultimately leading to a poor prognosis or even premature tooth loss. This significantly impacts patients\u0026rsquo; overall quality of life (Lu et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Qiao et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Xu et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Therefore, it is imperative to devote attention to the comprehensive analysis of factors influencing mobility in premolars among AgP patients.\u003c/p\u003e \u003cp\u003eThis study aimed to investigate the specific correlations between factors such as alveolar bone resorption, root morphology, the CRR, and periodontal clinical indicators and the tooth mobility of premolars in stage III/IV Grade C periodontitis patients\u0026thinsp;\u0026le;\u0026thinsp;35 years of age.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003ePatient population\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 151 AgP patients were enrolled in the periodontal Department of Peking University School and Hospital of Stomatology between 2001 and 2015.\u0026nbsp;The diagnosis of AgP was based on the following clinical and radiographic criteria proposed by the 1999 International World Workshop for a Classification of Periodontal Diseases and Conditions(Lang N, 1999).\u003c/p\u003e\n\u003cp\u003eThe inclusion criteria were as follows:\u003c/p\u003e\n\u003cp\u003e1) ≤35 years old;\u003c/p\u003e\n\u003cp\u003e2) at least 20 remaining teeth in the mouth;\u003c/p\u003e\n\u003cp\u003e3) At least 6 teeth have\u0026nbsp;a\u0026nbsp;probing depth\u0026nbsp;≥5 mm\u0026nbsp;and attachment loss of\u0026nbsp;≥3 mm\u0026nbsp;on adjacent surfaces;\u003c/p\u003e\n\u003cp\u003e4)\u0026nbsp;Non-smokers.\u003c/p\u003e\n\u003cp\u003eThese patients\u0026nbsp;were\u0026nbsp;diagnosed\u0026nbsp;with\u0026nbsp;stage III/IV grade C periodontitis according to the 2018 classification.\u003c/p\u003e\n\u003cp\u003eBefore diagnosis and treatment, full-mouth periapical radiographs of all subjects were taken by radiology technicians.\u0026nbsp;The study was approved by the Ethics Committee of PKUSS (approval number: PKUSSIIT02305).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical examinations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll clinical data, including the following indicators,\u0026nbsp;were obtained through repeated measurements by two experienced clinical physicians (Li Xu and Li Zhang): probing depth (PD), bleeding index (BI), and tooth mobility (TM). The average PD (APD)\u0026nbsp;was\u0026nbsp;determined by calculating the mean value of six measurement points for PD. Similarly, the average BI (ABI)\u0026nbsp;was\u0026nbsp;obtained by averaging measurements taken on both\u0026nbsp;the\u0026nbsp;buccal and lingual sides for\u0026nbsp;the\u0026nbsp;BI. The degree of tooth mobility is assessed using handheld dental examination forceps, and it is determined based on the direction and magnitude: if there is solely buccolingual movement, it is classified as degree 1; if there is movement in both\u0026nbsp;the\u0026nbsp;buccolingual and mesiodistal directions, it is classified as degree 2;\u0026nbsp;and\u0026nbsp;if vertical mobility occurs, it is classified as degree 3(Newman et al., 2015). Furthermore, considering the magnitude of tooth displacement, adjustments are made according to the principle of severity: tooth displacement less than 1 mm corresponds to degree 1,\u0026nbsp;tooth displacement between 1-2 mm corresponds to degree 2,\u0026nbsp;and\u0026nbsp;tooth displacement exceeding 2 mm corresponds to degree 3(Lindhe et al., 2015).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRadiographic analyses\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll periapical radiographs were confirmed to have\u0026nbsp;an\u0026nbsp;appropriate exposure time and suitable projection angle by experienced radiological technologists and clinical doctors,\u0026nbsp;and the inclusion criteria\u0026nbsp;for\u0026nbsp;periapical radiographs were as follows:\u003c/p\u003e\n\u003cp\u003e(1)\u0026nbsp;\u0026nbsp;Radiographs\u0026nbsp;should be accurately captured, ensuring precise positioning of the teeth at the center of the image and complete visibility of the entire tooth structure within the image boundaries;\u003c/p\u003e\n\u003cp\u003e(2)\u0026nbsp;\u0026nbsp;The image exhibits distinct clarity, with evident contrast in the photograph;\u003c/p\u003e\n\u003cp\u003e(3)\u0026nbsp;\u0026nbsp;The projection angle is appropriate, with the vertical angle accurately aligned and the length of the teeth closely approximating their actual measurements;\u003c/p\u003e\n\u003cp\u003e(4)\u0026nbsp;\u0026nbsp;The interproximal structure of the teeth appears well\u0026nbsp;defined and intact, exhibiting correct horizontal angles, no apparent overlap with adjacent structures, and\u0026nbsp;an\u0026nbsp;absence of caries, fillings, restorations or rotations;\u003c/p\u003e\n\u003cp\u003e(5)\u0026nbsp;\u0026nbsp;No abnormalities were\u0026nbsp;detected\u0026nbsp;in the periodontal ligament space (widening or disappearance), periodontal-pulp complex lesions, or residual roots.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;All included radiographic images were scanned for digital documentation (UMAX Powerlook1000 manual control,\u0026nbsp;600 dpi) and measured using GeoGebra\u0026nbsp;(Classic 5.0.735.0-d, International GeoGebra Institute, Linz, Austria)\u0026nbsp;by one researcher (Jia-Ming Li).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMeasurement of periapical radiographs\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1. Confirm point: Set point on the mesial and distal marginal ridge of crown (A, B); enamel-dentin junctions (C, D) situated mesial and distal; root apex point (G);\u0026nbsp;and\u0026nbsp;alveolar crest points (E, F) positioned mesial and distal\u0026nbsp;to\u0026nbsp;the target teeth.\u0026nbsp;The reference for alveolar ridge point confirmation is based on the research conducted by Schulte et al\u0026nbsp;(Schulte et al., 1992).\u003c/p\u003e\n\u003cp\u003e2. Confirm the tooth axis:\u0026nbsp;Researchers set the tooth axis by dividing the crown into two parts, based on the area below the marginal ridge of the crown and approximately two-thirds of the root crown surface,\u0026nbsp;both\u0026nbsp;mesial and distal. The varying degrees of curvature\u0026nbsp;of the apical third\u0026nbsp;can be disregarded when determining the tooth axis; thus, it is not necessary for the apical point to intersect with or pass through the tooth axis.\u003c/p\u003e\n\u003cp\u003e3. Measure crown-to-root ratio (CRR):\u0026nbsp;Connect the mesial and distal central\u0026nbsp;CEJs\u0026nbsp;(C, D), and draw parallel lines passing through the mesial and distal marginal ridge points (A, B),\u0026nbsp;respectively, intersecting the long axis of the tooth at two points (H, I).\u0026nbsp;The\u0026nbsp;midpoint between these two points\u0026nbsp;was selected\u0026nbsp;as the crown point (J).\u0026nbsp;A line\u0026nbsp;parallel to\u0026nbsp;the\u0026nbsp;CEJ passing through the root apex point (G), intersecting the long axis of the tooth at one point considered a hypothetical root apex point (K), was drawn. The\u0026nbsp;JL along\u0026nbsp;the\u0026nbsp;CEJ\u0026nbsp;was measured\u0026nbsp;as the crown length from J to K, which represents the\u0026nbsp;root length. The ratio of crown length to root length is defined as JL/KL.\u003c/p\u003e\n\u003cp\u003e4.\u0026nbsp;The\u0026nbsp;parameter of root width\u0026nbsp;(PRW)\u0026nbsp;was measured according\u0026nbsp;to the methodology proposed by Xu Li et al(Xu et al., 2009).\u0026nbsp;According to the research\u0026nbsp;of\u0026nbsp;Liu et al., root width can be categorized into two types, namely,\u0026nbsp;normal and cone roots, based on a threshold ratio of 0.37 between the surface area of the root collar and that below the ridge top(Liu et al., 2022);\u003c/p\u003e\n\u003cp\u003e5. Measure the extent of alveolar bone resorption:\u0026nbsp;Construct parallel lines to the CEJ passing through points E and F at varying distances from the alveolar crest. These lines intersect the long axis of the tooth at two distinct points (R and Q).\u0026nbsp;The\u0026nbsp;linear distance between these points (RK) and the hypothetical root\u0026nbsp;apex (QK) was measured. The average bone loss ratio (ABLR) was 1-.\u003c/p\u003e\n\u003cp\u003e6.\u0026nbsp;Bone level crown-root ratio\u0026nbsp;(B-CRR): B-CRR= (CRR+\u0026nbsp;ABLR)/(1-\u0026nbsp;ABLR).\u0026nbsp;This\u0026nbsp;indicator\u0026nbsp;can be utilized to estimate the remaining volume of periodontal membrane tissue and the lever arm magnitude during tooth loading, thereby partially reflecting the resistance torque generated by teeth when subjected to external forces.\u003c/p\u003e\n\u003cp\u003eThe\u0026nbsp;measurement\u0026nbsp;method used is depicted in Fig.\u0026nbsp;1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe statistical significance tests in this study were conducted using two-tailed tests, with a criterion of P\u0026lt;0.05 to determine significance. Different statistical analysis methods were chosen based on the type of data (categorical or continuous). The statistical analysis was performed using R 4.2.3 software [GUI 1.79 (8198 High Sierra build), S. Urbanek \u0026amp; H.-J. Bibiko, © R Foundation for Statistical Computing, 2021]. The analysis methods included t\u0026nbsp;tests, chi-square tests,\u0026nbsp;nonparametric\u0026nbsp;tests, and logistic regression analysis.\u003c/p\u003e\n\u003cp\u003eFor continuous data, normality testing was initially conducted to assess distribution characteristics. Normally distributed continuous data\u0026nbsp;are\u0026nbsp;presented as\u0026nbsp;the\u0026nbsp;mean ± standard deviation (x̄±s), while\u0026nbsp;nonnormally\u0026nbsp;distributed continuous data\u0026nbsp;are presented as the\u0026nbsp;median and interquartile range [M(P_25~P_75)]. Categorical data\u0026nbsp;are\u0026nbsp;expressed as rates or proportions.\u003c/p\u003e\n\u003cp\u003ePaired t\u0026nbsp;tests or analysis of variance (ANOVA) methods were employed for normally distributed continuous data; however, for\u0026nbsp;nonnormally\u0026nbsp;distributed variables such as\u0026nbsp;the crown–root\u0026nbsp;ratio and reference values for root width, either transformation techniques to achieve\u0026nbsp;a\u0026nbsp;normal distribution or\u0026nbsp;nonparametric\u0026nbsp;tests were utilized instead. Chi-square tests or similar approaches were used for categorical data.\u003c/p\u003e\n\u003cp\u003eMultiple factor analysis was performed to identify factors influencing tooth mobility. Tooth mobility served as the dependent variable (with control=I), which had more than two levels and passed the parallelism test with a result of P\u0026lt;0.05; therefore, an unordered multinomial logistic regression analysis was applied.\u003c/p\u003e\n\u003cp\u003eA backwards selection method was implemented to select variables and establish the optimal model that provides odds ratios (ORs) along with their corresponding 95% confidence intervals for relevant variables.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 1064 premolars from 151 stage III/IV grade C periodontitis patients ≤35 years of age were recruited.\u0026nbsp;A total of 72 males and 79 females\u0026nbsp;(mean age: 29.32 ± 3.06 years) were enrolled in this study. Among these, 286 maxillary first premolars (26.88%), 286 maxillary second premolars (26.88%), 236 mandibular first premolars (22.18%), and 256 mandibular second premolars (24.06%)\u0026nbsp;were included.\u0026nbsp;The\u0026nbsp;numbers\u0026nbsp;of mobile premolars with degrees 0, I, II and III were 213, 458, 300 and 93, respectively.\u003c/p\u003e\n\u003cp\u003eThe average root length of\u0026nbsp;the\u0026nbsp;1064 premolars was 12.60 ±2.13 mm, with a range of 6.80-20.96 mm. Root\u0026nbsp;length was considered a continuous variable,\u0026nbsp;and these teeth were equally categorized into three groups based on their root\u0026nbsp;length: short, medium, and long roots. The mean root lengths for these groups were 10.22±1.12 mm, 12.67±0.54 mm, and 14.91±2.13 mm,\u0026nbsp;respectively, exhibiting an approximate difference of 2 mm between each group's mean\u0026nbsp;values. The average crown lengths were similar\u0026nbsp;among the\u0026nbsp;three groups (5.12±0.67 mm, 5.07±0.78 mm,\u0026nbsp;and\u0026nbsp;5.07±0.77 mm, P=0.515). However, when comparing the\u0026nbsp;CRRs\u0026nbsp;across the three groups, statistically significant\u0026nbsp;differences\u0026nbsp;were detected (0.51±0.09 for the short root group, 0.40±0.07 for the medium root group, 0.34±0.05 for the long root group, P=0.000).\u003c/p\u003e\n\u003cp\u003eThe mean values of\u0026nbsp;the\u0026nbsp;PRW in\u0026nbsp;the\u0026nbsp;three groups were 0.56±0.23 mm, 0.57±0.63 mm, and 0.58±0.55 mm,\u0026nbsp;respectively, with no statistically significant differences observed (P=0.830).\u003c/p\u003e\n\u003cp\u003eWhen the degree of tooth mobility\u0026nbsp;was\u0026nbsp;the same, significant variations in alveolar bone resorption were observed among\u0026nbsp;the\u0026nbsp;three groups with short, medium, and long roots.\u0026nbsp;The\u0026nbsp;average alveolar bone absorption for each group at grade I mobility\u0026nbsp;was\u0026nbsp;0.28 ± 0.15 for the short root group, 0.34 ± 0.14 for the medium root group, and 0.37 ± 0.13 for the long root group\u0026nbsp;(P=0.000).\u003c/p\u003e\n\u003cp\u003eWhen the degree of tooth mobility\u0026nbsp;was\u0026nbsp;the same, there\u0026nbsp;were\u0026nbsp;no statistically significant differences in the B-CRR\u0026nbsp;among\u0026nbsp;the\u0026nbsp;short-, medium-\u0026nbsp;and long-root\u0026nbsp;groups. The 95% confidence intervals for the B-CRRs\u0026nbsp;of premolars with mobility\u0026nbsp;grades of\u0026nbsp;0, I, II, and III were 0.68, 0.74, 1.07, 1.16, 1.43, 1.59, and 2.13, 2.89,\u0026nbsp;respectively\u0026nbsp;(Table\u0026nbsp;1).\u003c/p\u003e\n\u003cp\u003eThe\u0026nbsp;APD, ABI, root length, crown length, CRR, ABLR, maximum BLR,\u0026nbsp;and\u0026nbsp;B-CRR exhibited significant variations among\u0026nbsp;the\u0026nbsp;different degrees of tooth mobility (Table\u0026nbsp;2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMultilevel logistic regression model for factors influencing\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003epremolar\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;mobility\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBased on the results of univariate analysis, a multilevel logistic regression model was developed to classify tooth mobility into four categories (0, I, II, III), incorporating the following key indicators: ABLR, maximum BLR,\u0026nbsp;and\u0026nbsp;B-CRR. Due to their lower retention rate in clinical practice (often leading to extraction), teeth with\u0026nbsp;Grade\u0026nbsp;III mobility were underrepresented. Consequently, for consideration purposes, the model merged teeth with grade II and III mobility. The regression\u0026nbsp;results\u0026nbsp;are presented in Table 3.\u003c/p\u003e\n\u003cp\u003eThe three multiple-level logistic regression models all showed significant differences (P\u0026lt;0.001). Model 3 had the lowest AIC (1700.574) and residual (1676.574), indicating the best performance. At a significance level of α=0.05, compared to teeth with mobility degree I as a reference, teeth with no mobility degree 0 showed significant differences in APD (P\u0026lt;0.001, OR=0.681), root length (P\u0026lt;0.05, OR=1.142), and B-CRR (P\u0026lt;0.001, OR=0.017). There were also significant differences in the APD (P\u0026lt;0.001, OR=1.581) and B-CRR (P\u0026lt;0.05, OR=0.824) between teeth with mobility degrees II and III.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, we investigated the factors influencing\u0026nbsp;the\u0026nbsp;tooth mobility of premolars in\u0026nbsp;stage III/IV grade C periodontitis patients ≤35 years of age.\u0026nbsp;First, significant variations in\u0026nbsp;the\u0026nbsp;length of\u0026nbsp;the roots of premolars, ranging from 6.80 mm\u0026nbsp;to 20.96 mm, were detected, while no difference in crown length\u0026nbsp;was detected. Therefore, our findings suggested that\u0026nbsp;the\u0026nbsp;CRR is primarily determined by root length, which aligns with previous research conducted by our team\u003csup\u003e8\u003c/sup\u003e.\u0026nbsp;At\u0026nbsp;the same\u0026nbsp;time, the long-root group exhibited greater alveolar bone resorption\u0026nbsp;than\u0026nbsp;both\u0026nbsp;the medium-root and short-root groups. Consequently, it can be inferred that shorter roots are more prone to experiencing and displaying increased mobility when alveolar bone resorption is equal. Teeth with shorter roots (with an\u0026nbsp;average root length\u0026nbsp;of\u0026nbsp;approximately 10.22 mm) can exhibit grade I mobility with an ABLR of only 28%, while teeth with medium roots (with an\u0026nbsp;average root length\u0026nbsp;of\u0026nbsp;approximately 12.67 mm) can experience grade I mobility with an ABLR of 34%. On the other hand, teeth with longer roots (with an\u0026nbsp;average root length\u0026nbsp;of\u0026nbsp;approximately 14.91 mm) display grade I mobility\u0026nbsp;only\u0026nbsp;when\u0026nbsp;the\u0026nbsp;ABLR\u0026nbsp;is\u0026nbsp;37%. This finding effectively elucidates why teeth with shorter roots tend to become mobile. Therefore, it is evident that assessing the prognosis of teeth solely based on BL%/age without considering root length lacks rigor.\u003c/p\u003e\n\u003cp\u003eTherefore, if the degree of tooth mobility is primarily estimated by ABLR, it necessitates adjustment based on root length. This study revealed no significant\u0026nbsp;difference\u0026nbsp;in the B-CRR among\u0026nbsp;the\u0026nbsp;three groups with short, medium, and long roots under equivalent degrees of mobility.\u0026nbsp;This\u0026nbsp;implies that the B-CRR remains unaffected by\u0026nbsp;the\u0026nbsp;absolute root length and can more effectively differentiate degrees of mobility. In essence, irrespective of varying levels of alveolar bone absorption and differing root lengths, tooth mobility can be roughly assessed based on\u0026nbsp;the\u0026nbsp;B-CRR without further modification. The B-CRR threshold values for grade I, II, and III mobility are 1, 1.3, and 1.9,\u0026nbsp;respectively. When\u0026nbsp;the\u0026nbsp;B-CRR reaches or exceeds 1, it indicates grade I mobility; when it reaches or exceeds 1.9, it indicates grade III mobility. Based on clinical experience corroborated for the first time through specific numerical values in this study, tooth mobility occurs when\u0026nbsp;the\u0026nbsp;B-CRR is approximately equal to 1.\u003c/p\u003e\n\u003cp\u003eTherefore, in the future, dentists or big data analysis could preliminarily estimate tooth mobility based on\u0026nbsp;the\u0026nbsp;B-CRR; however, if there is a substantial discrepancy between tooth mobility and\u0026nbsp;the\u0026nbsp;B-CRR, then occlusal factors or other non-periodontitis-related alveolar bone loss should be considered. Additionally, caution should be exercised when considering treatment plans such as crown elongation or orthodontic movement for premolars when\u0026nbsp;the\u0026nbsp;B-CRR reaches 1.\u003c/p\u003e\n\u003cp\u003eThe mobility of teeth under external forces is the result of rotational movement caused by mechanical forces applied to the teeth. The factors influencing tooth mobility can be categorized into three aspects: external force (dynamic force), resistance, and dynamic and resistance\u0026nbsp;arms. During functional loading (chewing), occlusal forces primarily contribute to the external forces experienced by teeth. In this study, external force refers to a stable and appropriately sized force applied by researchers on the dental crown during clinical examination.\u0026nbsp;Resistance\u0026nbsp;primarily arises from the deformation of\u0026nbsp;nonrigid\u0026nbsp;periodontal tissues, which is intricately linked to the volume (surface area and width), composition, and structure of the periodontal ligament(Storey, 1973).\u003c/p\u003e\n\u003cp\u003eWhen the root is short, tapered,\u0026nbsp;or\u0026nbsp;single, its periodontal ligament\u0026nbsp;has\u0026nbsp;a relatively reduced surface area. Consequently, given an equivalent degree of alveolar bone absorption, it becomes more susceptible to\u0026nbsp;mobility. The width of the periodontal ligament space\u0026nbsp;is closely correlated\u0026nbsp;with changes in tissue structure and occlusal force(Denes et al., 2013; Nanci \u0026amp; Bosshardt, 2006; Niver et al., 2011). The present study excluded teeth with widened or narrowed periodontal ligament space on periapical films to minimize the potential influence of abnormal periodontal ligament width on tooth mobility.\u0026nbsp;In addition, the presence of inflammation in the periodontium leads to an increase in mobility due to a decrease in collagen fibres, an\u0026nbsp;increase in\u0026nbsp;blood vessels, pathological alterations in fibroblasts, and disruption of the structure and alignment of the main fibres within the periodontal ligament(Attstrom, 1970; Goellner et al., 2013b; Zoellner \u0026amp; Hunter, 1994).\u0026nbsp;This\u0026nbsp;results in diminished resistance provided by the periodontal tissues.\u0026nbsp;The present study further\u0026nbsp;validated\u0026nbsp;the association between periodontal inflammation (PD, BI,\u0026nbsp;etc.) and tooth mobility.\u003c/p\u003e\n\u003cp\u003eThe center of resistance represents the point at which the combined forces acting on teeth achieve equilibrium, thereby reflecting factors such as root morphology and\u0026nbsp;the\u0026nbsp;degree of alveolar bone resorption. In this study, we utilized\u0026nbsp;the\u0026nbsp;B-CRR to estimate resistance and determine the center of resistance, providing a more comprehensive assessment of\u0026nbsp;the\u0026nbsp;influential factors affecting tooth mobility. Furthermore, our model demonstrated that the B-CRR serves as an optimal variable for evaluating tooth mobility.\u003c/p\u003e\n\u003cp\u003eFor nearly four decades, since the advent of electronic mechanical instruments\u0026nbsp;such as\u0026nbsp;Periotest for quantifying tooth mobility, some studies have employed these devices to objectively measure tooth mobility. However, due to inherent design limitations, these devices primarily\u0026nbsp;assess\u0026nbsp;unidirectional mobility (buccolingual or axial) with a maximum displacement of ≤2 mm, rendering them suitable only for evaluating mild alveolar bone resorption in anterior teeth(Andresen et al., 2003; Goellner et al., 2013a; Muhlemann, 1967; Schulte, 1988; Schulte et al., 1992).\u0026nbsp;Consequently, for teeth in the posterior area with moderate or severe periodontal destruction\u0026nbsp;and\u0026nbsp;exhibiting multidirectional movement or\u0026nbsp;displacement ≥2 mm, comprehensive evaluations of\u0026nbsp;the factors influencing mobility\u0026nbsp;are lacking.\u0026nbsp;The Periotest value (PTV) did not exhibit any significant correlation with the clinically measured displacement of teeth(Goellner et al., 2012).\u0026nbsp;Therefore, the present study used the common approach of assessing tooth mobility using handheld dental forceps and categorizing it into various degrees according to its direction and displacement.\u003c/p\u003e\n\u003cp\u003eThere are certain limitations in this study. The regression model results demonstrated a significant association between root length and tooth mobility, while no significant relationship was observed between root width and tooth mobility. However, it should be noted that the evaluation of buccolingual conditions not captured in the assessment of apical films was not considered, indicating some limitations in the evaluation process(Liu et al., 2022). There are also several other limitations, including the inclusion of a small number of grade III mobile teeth in the study, the evaluation of root and alveolar bone conditions through two-dimensional periapical films, and the restriction to premolars. Although three-dimensional CBCT currently offers advantages in observing root and alveolar bone, promoting the use of periapical films as the most widely used imaging examination in clinical practice is warranted. This study has significant clinical value and merits further research, such as expanding to incisors and molars, proposing the establishment of databases and large medical services for building models, and utilizing artificial intelligence to enhance the accuracy and reliability of prediction models for clinical application, ultimately benefiting patients.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study provides preliminary evidence that tooth mobility in patients with AgP is associated with the crown-root ratio, level of alveolar bone resorption, and probing depth of premolars. The bone-level crown-root ratio effectively predicts tooth mobility at different root lengths and levels of alveolar bone resorption, offering clinicians valuable insights for assessing factors contributing to tooth mobility and making prognosis judgments for teeth with varying root lengths. Moreover,\u0026nbsp;this study\u0026nbsp;lays the foundation for future applications of big data artificial intelligence in rapidly estimating tooth mobility based on periapical radiographs.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Peking University Ethics Committee and Competent Authority (No.\u0026nbsp;PKUSSIRB-202495004). Consent was obtained from all participants in this study. All patients in our hospital will sign informed consent before receiving oral treatment, which includes that the patient's medical records can be used for teaching and research. This study was performed in accordance with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. The datasets generated and/or analysed during the current study are not publicly available due patient imaging data is a matter of personal privacy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eJia-Ming Li, Xian-E Wang, Li Xu and Huan-Xin Meng conceived and presented this study.\u003c/p\u003e\n\u003cp\u003eJia-Ming Li, Xian-E Wang\u0026nbsp;wrote the main manuscript text and prepared figures and tables.\u003c/p\u003e\n\u003cp\u003eXiao Xu and Jian Liu offered help with imaging measurements.\u003c/p\u003e\n\u003cp\u003eLi Zhang, Xiang-Hui Feng and Rui-Fang Lu were responsible for collecting clinical data.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll authors reviewed the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAndresen, M., Mackie, I., \u0026amp; Worthington, H. (2003). The Periotest in traumatology. Part I. Does it have the properties necessary for use as a clinical device and can the measurements be interpreted? \u003cem\u003eDental Traumatology\u003c/em\u003e,\u003cem\u003e\u0026nbsp;19\u003c/em\u003e(4), 214-217. https://doi.org/DOI 10.1034/j.1600-9657.2003.00165.x\u003c/li\u003e\n \u003cli\u003eAttstrom, R. (1970). Presence of leukocytes in crevices of healthy and chronically inflamed gingivae. \u003cem\u003eJ Periodontal Res\u003c/em\u003e,\u003cem\u003e\u0026nbsp;5\u003c/em\u003e(1), 42-47. https://doi.org/10.1111/j.1600-0765.1970.tb01836.x\u003c/li\u003e\n \u003cli\u003eDenes, B. J., Mavropoulos, A., Bresin, A., \u0026amp; Kiliaridis, S. (2013). Influence of masticatory hypofunction on the alveolar bone and the molar periodontal ligament space in the rat maxilla. \u003cem\u003eEur J Oral Sci\u003c/em\u003e,\u003cem\u003e\u0026nbsp;121\u003c/em\u003e(6), 532-537. https://doi.org/10.1111/eos.12092\u003c/li\u003e\n \u003cli\u003eEricsson, I., \u0026amp; Lindhe, J. (1984). Lack of significance of increased tooth mobility in experimental periodontitis. \u003cem\u003eJ Periodontol\u003c/em\u003e,\u003cem\u003e\u0026nbsp;55\u003c/em\u003e(8), 447-452. https://doi.org/10.1902/jop.1984.55.8.447\u003c/li\u003e\n \u003cli\u003eGiargia, M., \u0026amp; Lindhe, J. (1997). Tooth mobility and periodontal disease. \u003cem\u003eJ Clin Periodontol\u003c/em\u003e,\u003cem\u003e\u0026nbsp;24\u003c/em\u003e(11), 785-795. https://doi.org/10.1111/j.1600-051x.1997.tb01190.x\u003c/li\u003e\n \u003cli\u003eGoellner, M., Berthold, C., Holst, S., Petschelt, A., Wichmann, M., \u0026amp; Schmitt, J. (2013a). Influence of attachment and bone loss on the mobility of incisors and canine teeth. \u003cem\u003eActa Odontologica Scandinavica\u003c/em\u003e,\u003cem\u003e\u0026nbsp;71\u003c/em\u003e(3-4), 656-663. https://doi.org/10.3109/00016357.2012.711488\u003c/li\u003e\n \u003cli\u003eGoellner, M., Berthold, C., Holst, S., Petschelt, A., Wichmann, M., \u0026amp; Schmitt, J. (2013b). Influence of attachment and bone loss on the mobility of incisors and canine teeth. \u003cem\u003eActa Odontol Scand\u003c/em\u003e,\u003cem\u003e\u0026nbsp;71\u003c/em\u003e(3-4), 656-663. https://doi.org/10.3109/00016357.2012.711488\u003c/li\u003e\n \u003cli\u003eGoellner, M., Berthold, C., Holst, S., Wichmann, M., \u0026amp; Schmitt, J. (2012). Correlations between photogrammetric measurements of tooth mobility and the Periotest method. \u003cem\u003eActa Odontologica Scandinavica\u003c/em\u003e,\u003cem\u003e\u0026nbsp;70\u003c/em\u003e(1), 27-35. https://doi.org/10.3109/00016357.2011.575080\u003c/li\u003e\n \u003cli\u003eLang N, e. a. (1999). Consensus Report: Aggressive Periodontitis.\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003cem\u003eAnn Peri odontol\u003c/em\u003e,\u003cem\u003e\u0026nbsp;4\u003c/em\u003e(1), 53-53.\u003c/li\u003e\n \u003cli\u003eLee, C. T., Zhang, K., Li, W., Tang, K., Ling, Y., Walji, M. F., \u0026amp; Jiang, X. (2023). Identifying predictors of tooth loss using a rule-based machine learning approach: A retrospective study at university-setting clinics. \u003cem\u003eJ Periodontol\u003c/em\u003e,\u003cem\u003e\u0026nbsp;94\u003c/em\u003e(10), 1231-1242. https://doi.org/10.1002/JPER.23-0030\u003c/li\u003e\n \u003cli\u003eLindhe, J., Lang, N. P., Berglundh, T., Giannobile, W. V., Sanz, M., \u0026amp; Ebook Central Academic, C. (2015). \u003cem\u003eClinical periodontology and implant dentistry\u003c/em\u003e (Sixth edition. ed.). Wiley Blackwell. http://ebookcentral.proquest.com/lib/liverpool/detail.action?docID=2006107\u003c/li\u003e\n \u003cli\u003eLiu, J., Xu, X., Wang, X. E., Jia, P. C., Pan, M. Q., \u0026amp; Xu, L. (2022). A novel three-dimensional quantitative assessment method for abnormal root morphology of the maxillary premolars in vivo on cone-beam computed tomography. \u003cem\u003eBmc Oral Health\u003c/em\u003e,\u003cem\u003e\u0026nbsp;22\u003c/em\u003e(1), 229. https://doi.org/10.1186/s12903-022-02258-3\u003c/li\u003e\n \u003cli\u003eLu, D., Meng, H. X., Xu, L., Wang, X. E., Zhang, L., \u0026amp; Tian, Y. (2017). Root abnormalities and nonsurgical management of generalized aggressive periodontitis. \u003cem\u003eJournal of Oral Science\u003c/em\u003e,\u003cem\u003e\u0026nbsp;59\u003c/em\u003e(1), 103-110. https://doi.org/10.2334/josnusd.16-0258\u003c/li\u003e\n \u003cli\u003eMuhlemann, H. R. (1967). Tooth Mobility - a Review of Clinical Aspects and Research Findings. \u003cem\u003eJournal of Periodontology\u003c/em\u003e,\u003cem\u003e\u0026nbsp;38\u003c/em\u003e(6p2), 686-+. \u0026lt;Go to ISI\u0026gt;://WOS:A1967A769400021\u003c/li\u003e\n \u003cli\u003eMuhlemann, H. R. (1969). Pathological tooth mobility. \u003cem\u003eAnnu Meet Am Inst Oral Biol\u003c/em\u003e, 99-101. https://www.ncbi.nlm.nih.gov/pubmed/5261362\u003c/li\u003e\n \u003cli\u003eNanci, A., \u0026amp; Bosshardt, D. D. (2006). Structure of periodontal tissues in health and disease. \u003cem\u003ePeriodontology 2000\u003c/em\u003e,\u003cem\u003e\u0026nbsp;40\u003c/em\u003e, 11-28. https://doi.org/10.1111/j.1600-0757.2005.00141.x\u003c/li\u003e\n \u003cli\u003eNewman, M. G., Takei, H. H., Klokkevold, P. R., \u0026amp; Carranza, F. A. (2015). \u003cem\u003eCarranza\u0026apos;s clinical periodontology\u003c/em\u003e (Twelfth edition. ed.). Elsevier Saunders.\u003c/li\u003e\n \u003cli\u003eNiver, E. L., Leong, N., Greene, J., Curtis, D., Ryder, M. I., \u0026amp; Ho, S. P. (2011). Reduced functional loads alter the physical characteristics of the bone-periodontal ligament-cementum complex. \u003cem\u003eJ Periodontal Res\u003c/em\u003e,\u003cem\u003e\u0026nbsp;46\u003c/em\u003e(6), 730-741. https://doi.org/10.1111/j.1600-0765.2011.01396.x\u003c/li\u003e\n \u003cli\u003ePersson, R., \u0026amp; Svensson, A. (1980). Assessment of tooth mobility using small loads. I. Technical devices and calculations of tooth mobility in periodontal health and disease. \u003cem\u003eJ Clin Periodontol\u003c/em\u003e,\u003cem\u003e\u0026nbsp;7\u003c/em\u003e(4), 259-275. https://doi.org/10.1111/j.1600-051x.1980.tb01969.x\u003c/li\u003e\n \u003cli\u003eQiao, M., Xu, L., Meng, H. X., Tian, Y., Zhang, L., \u0026amp; Feng, X. H. (2013). [Alveolar bone loss in nuclear families of aggressive periodontitis and the heredity of root shape]. \u003cem\u003eZhonghua Kou Qiang Yi Xue Za Zhi\u003c/em\u003e,\u003cem\u003e\u0026nbsp;48\u003c/em\u003e(10), 577-580. https://www.ncbi.nlm.nih.gov/pubmed/24438562\u003c/li\u003e\n \u003cli\u003eSchulte, W. (1988). The new Periotest method. \u003cem\u003eCompend Suppl\u003c/em\u003e(12), S410-415, S417. https://www.ncbi.nlm.nih.gov/pubmed/3271598\u003c/li\u003e\n \u003cli\u003eSchulte, W., d\u0026apos;Hoedt, B., Lukas, D., Maunz, M., \u0026amp; Steppeler, M. (1992). Periotest for measuring periodontal characteristics--correlation with periodontal bone loss. \u003cem\u003eJ Periodontal Res\u003c/em\u003e,\u003cem\u003e\u0026nbsp;27\u003c/em\u003e(3), 184-190. https://doi.org/10.1111/j.1600-0765.1992.tb01667.x\u003c/li\u003e\n \u003cli\u003eShi, S., Meng, Y., Li, W., Jiao, J., Meng, H., \u0026amp; Feng, X. (2020). A nomogram prediction for mandibular molar survival in Chinese patients with periodontitis: A 10-year retrospective cohort study. \u003cem\u003eJ Clin Periodontol\u003c/em\u003e,\u003cem\u003e\u0026nbsp;47\u003c/em\u003e(9), 1121-1131. https://doi.org/10.1111/jcpe.13343\u003c/li\u003e\n \u003cli\u003eStorey, E. (1973). The nature of tooth movement. \u003cem\u003eAm J Orthod\u003c/em\u003e,\u003cem\u003e\u0026nbsp;63\u003c/em\u003e(3), 292-314. https://doi.org/10.1016/0002-9416(73)90353-9\u003c/li\u003e\n \u003cli\u003eTonetti, M. S., Greenwell, H., \u0026amp; Kornman, K. S. (2018). Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. \u003cem\u003eJ Clin Periodontol\u003c/em\u003e,\u003cem\u003e\u0026nbsp;45 Suppl 20\u003c/em\u003e, S149-S161. https://doi.org/10.1111/jcpe.12945\u003c/li\u003e\n \u003cli\u003eXu, L., Meng, H. X., Tian, Y., Zhang, L., Feng, X. H., \u0026amp; Zhang, G. (2009). [Evaluation of root abnormity in patients with aggressive periodontitis]. \u003cem\u003eZhonghua Kou Qiang Yi Xue Za Zhi\u003c/em\u003e,\u003cem\u003e\u0026nbsp;44\u003c/em\u003e(5), 266-269. https://www.ncbi.nlm.nih.gov/pubmed/19575981\u003c/li\u003e\n \u003cli\u003eXu, L., Meng, H. X., Zhang, L., Feng, X. H., Shi, D., \u0026amp; Tian, Y. (2010). [Analysis of alveolar bone loss and related factors in patients with aggressive periodontitis]. \u003cem\u003eZhonghua Kou Qiang Yi Xue Za Zhi\u003c/em\u003e,\u003cem\u003e\u0026nbsp;45\u003c/em\u003e(12), 745-748. https://www.ncbi.nlm.nih.gov/pubmed/21211242\u003c/li\u003e\n \u003cli\u003eZoellner, H., \u0026amp; Hunter, N. (1994). The Vascular-Response in Chronic Periodontitis. \u003cem\u003eAustralian Dental Journal\u003c/em\u003e,\u003cem\u003e\u0026nbsp;39\u003c/em\u003e(2), 93-97. https://doi.org/DOI 10.1111/j.1834-7819.1994.tb01380.x\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 3 are available in the Supplementary Files section\u003c/p\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":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"tooth mobility, stage III/IV grade C periodontitis, alveolar bone resorption, tooth root morphology, multifactorial analysis","lastPublishedDoi":"10.21203/rs.3.rs-4635163/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4635163/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003ePrevious studies has revealed a potential association between crown-root ratio and root morphology in patients with mild chronic periodontitis, suggesting a possible link to tooth mobility. However, further comprehensive analytical investigations were not pursued. Our previous study observed that 76% of aggressive periodontitis patients exhibit abnormal root morphology, especially in premolars, associated with severe alveolar bone loss and mobility, leading to poor clinical outcomes. This study aims to investigate the specific correlations between factors such as alveolar bone resorption, root morphology, crown-root ratio, and periodontal clinical indicators with tooth mobility of premolars in stage III/IV grade C periodontitis patients ≤35 years of age.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and methods: \u003c/strong\u003eA total of 1064 premolars from 151 stage III/IV grade C periodontitis patients ≤35 years of age were recruited. Clinical periodontal parameters and radiographic parameters were recorded. Logistic regression analysis was employed to investigate the relationships between these indicators and tooth mobility.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e The difference in the length of the premolar roots wassignificant, ranging from 6.80 mm-20.96 mm. Teeth with shorter roots (mean root length of 10.22 mm) exhibitedgrade I mobility with only 28% alveolar bone resorption, while the percentages ofmedium-length roots (mean root length of 12.67 mm) and longer roots(average of 14.91 mm) exhibiting alveolar bone resorptionwere 34% and 37%, respectively. In terms of classifying the degree of mobility, multiple regression models incorporating the crown-root ratio at the bone level, average probing depth and root length demonstrated optimal performance (P\u0026lt;0.001, AIC=1700.574).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e Premolar mobility is associated with variations in root length, alveolar bone resorption, and probing depth. The crown-root ratio at the bone level can effectively serve as a predictor for assessing tooth mobility when there are discrepancies in root length and extent of alveolar bone resorption.\u003c/p\u003e","manuscriptTitle":"Multifactorial analysis of factors influencing premolar mobility in stage III/IV grade C periodontitis patients ≤35 years of age: A cross-sectional study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-23 13:01:34","doi":"10.21203/rs.3.rs-4635163/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-09-09T08:36:21+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-07T15:20:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"71965332315633673944297098602003366133","date":"2024-08-25T13:11:22+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-08T13:24:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"234538854531251908654549701260602465546","date":"2024-07-17T16:01:29+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-07-04T14:34:46+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-07-02T09:54:02+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-30T12:15:23+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-30T12:13:47+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2024-06-25T09:17:16+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ff70d92e-79d7-4aa6-bd76-a6101e97e238","owner":[],"postedDate":"July 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-21T16:11:03+00:00","versionOfRecord":{"articleIdentity":"rs-4635163","link":"https://doi.org/10.1186/s12903-024-05039-2","journal":{"identity":"bmc-oral-health","isVorOnly":false,"title":"BMC Oral Health"},"publishedOn":"2024-10-16 15:57:44","publishedOnDateReadable":"October 16th, 2024"},"versionCreatedAt":"2024-07-23 13:01:34","video":"","vorDoi":"10.1186/s12903-024-05039-2","vorDoiUrl":"https://doi.org/10.1186/s12903-024-05039-2","workflowStages":[]},"version":"v1","identity":"rs-4635163","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4635163","identity":"rs-4635163","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}