External Root Resorption of Second Molars Caused by Impacted Third Molars: CBCT characteristics

External Root Resorption of Second Molars Caused by Impacted Third Molars: CBCT characteristics | 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 External Root Resorption of Second Molars Caused by Impacted Third Molars: CBCT characteristics Kan Wang, Jiajia Zheng, Jinghua He, Yuan Fu, Xiaoming Lyu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6759855/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Sep, 2025 Read the published version in Oral and Maxillofacial Surgery → Version 1 posted 9 You are reading this latest preprint version Abstract Objectives This study aims to describe the cone-beam computed tomography (CBCT) characteristics of external root resorption (ERR) in second molars associated with impacted third molars. Methods This study analyzed 69 second molars diagnosed with ERR caused by impacted third molars in 52 patients (age range: 22–59 years; mean age = 31.2 ± 7.1 years) to identify key factors influencing the severity and occurrence of ERR. CBCT was used to assess the relationship between impacted third molar characteristics (position, angulation, proximity) and the extent of root resorption in adjacent second molars. Results ERR most commonly affected mandibular second molars (37 teeth: 60.0%, 47 teeth: 40.6%). Resorption extended to the pulp chamber in 47.9% of cases, while 40.6% was limited to superficial/middle dentin. 24.6% of the ERR sites were in communication with the oral cavity. Eighty-four cases of third molars were associated with external resorption of the second molars.87% of impacted third molars were low-level, and 38% were completely bone-impacted. 26% had an angulation > 90° relative to the affected tooth. Complete bone impaction significantly correlated with ERR extending to the pulp chamber (65%, p < 0.05). ERR communicating with the oral cavity significantly increased pain on percussion. Younger patients were more likely to have ERR extending to the pulp chamber. Conclusions Low-level and complete bone impactions of impacted third molars significantly contribute to the development of ERR in adjacent second molars. Communication between the ERR site and the oral cavity is associated with a high risk of infection. cone-beam computed tomography (CBCT) External root resorption (ERR) second molar impacted third molar Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction External root resorption (ERR) is a pathological condition characterized by the progressive loss of dental root structure due to the activity of odontoclasts, often triggered by mechanical pressure, inflammation, or trauma . Among the various etiologies, the impaction of third molars has been recognized as a significant contributing factor to ERR in adjacent second molars . Impacted third molars, due to their abnormal position or lack of space for proper eruption, can exert sustained pressure on the roots of neighboring teeth, leading to resorption over time . In the adult population, the overall incidence of impacted teeth is approximately 20%, with mandibular third molars being the most commonly impacted . This phenomenon compromises the structural integrity of affected second molars, with significant long-term consequences such as reduced tooth stability, increased risk of periodontal complications, and potential tooth loss. The prognosis of second molars affected by ERR from impacted third molars is of critical concern to dentists. While some cases of resorption may remain asymptomatic and undetected until advanced stages, others can progress rapidly, necessitating complex interventions such as tooth extraction . The heterogeneity in the progression and clinical outcomes of ERR necessitates a comprehensive understanding of relevant prognostic indicators. These include the degree of third molar impaction , the three-dimensional spatial relationship with the adjacent second molar, in particular, the presence of communication between the external resorption site and the oral cavity, and patient-specific variables such as age and overall health status. Identification and accurate risk stratification for ERR are critical for informed clinical decision-making, facilitating both prophylactic strategies and therapeutic interventions aimed at preserving the functional integrity and long-term viability of the second molar . While Cone-beam computed tomography (CBCT) enhances the assessment of anatomical relationships between impacted third molars and adjacent second molars, a lack of large-scale radiographic studies limits our understanding of the natural of ERR . Since ERR is frequently asymptomatic , this study utilizes CBCT to investigate its characteristics in second molars adjacent to impacted third molars. By analyzing CBCT findings from clinical cases, we aim to evaluate the severity of resorption. The primary goal is to identify key predictors, thereby generating evidence-based insights to enhance risk stratification and guide clinical decision-making regarding impacted third molars. Materials and Methods Ethics Statement This study was approved by the Ethics Committee of Peking University School and Hospital of Stomatology (approval number: PKUSSIRB-202165092) and was registed on National Health Security Information Platform by National Health Commission of People’s Republic of China (pid:263774). Patients were consented by an informed consent process that was reviewed by the Ethics Committee of Peking University School and Hospital of Stomatology and certify that the study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki. Study Population This retrospective study reviewed patients diagnosed with ERR between September 2021 and September 2024, selected from the dental records of the Second Clinical Division, Peking University School and Hospital of Stomatology. Data were collected on patient demographics (age and gender), the site of ERR and associated clinical symptoms, clinical examination findings (mobility of the affected tooth, probing depth (PD), percussion response, pulp vitality tests, and presence of communication with the oral cavity), and radiographic outcomes. Using CBCT, the location of maximum root resorption on the second molar was determined. Imaging parameters included a voltage of 90 kV, a current of 6 mA, an exposure time of 16 seconds, and a slice thickness of 0.125 mm. The maximum cross-sectional plane at this level was obtained. Within this plane, the long axes of the second and third molars were delineated. The angle between these two axes was calculated, with the measurement oriented toward the direction of external root resorption. Inclusion criteria were as follows: (1) presence of at least one impacted third molar in contact with the adjacent second molar, (2) CBCT evidence of ERR on the second molar; Exclusion criteria included: (1) history of orthodontic treatment involving the affected teeth, (2) prior surgical intervention on the third molar, and (3) incomplete clinical or radiographic records. CBCT scans were analyzed to record the following parameters for each case: (1)Angulation of the impacted third molar. (2) Depth of associated root resorption on the second molar (superficial, at the cementoenamel junction [CEJ], or apical to the CEJ). (3) Degree of impaction (partial or full). (4)ERR Severity: Mild ERR, root resorption does not exceed half of the root canal wall thickness. Moderate ERR, root resorption has exceeded half of the root canal wall thickness but not yet involved the root cannal system. Severe ERR, root resorption involves the root cannal system. CBCT images were analyzed using SmartVPro version 2.0 by two independent examiners blinded to patient details. The relationship between the impacted third molar and the second molar root was evaluated in three dimensions (axial, coronal, and sagittal planes). ERR was quantified by measuring the length of the resorbed root segment relative to the total root length from the cementoenamel junction to the apex. Statistical Analysis Data were analyzed using SPSS version 26.0. Descriptive statistics (means, standard deviations, and percentages) were used to summarize patient characteristics, impaction patterns, and ERR severity. The association between prognostic factors (e.g., impaction angulation, depth, age, and periodontal status) and ERR progression was assessed using chi-square tests for categorical variables and independent t-tests or ANOVA for continuous variables. Multivariate logistic regression was employed to identify independent predictors of severe ERR (Cervical 1/3), with odds ratios (OR) and 95% confidence intervals (CI) calculated. A p-value of < 0.05 was considered statistically significant. Results This study analyzed 69 second molars with diagnosed external root resorption (ERR) across 52 patients. Radiographic confirmation established that ERR in all cases was associated with adjacent impacted third molars. Patient demographic characteristics are presented in Table 1 . The age range of the patients was 22–59 years, with an average age of 31.2 years. Table 1 Patient demographic characteristics(N = 52) Gender Number Percentage% Male 23 44.2 Female 29 55.8 Age Group 20–29 years 23 44.2 30–39 years 22 42.3 40–49 years 3 5.8 50–59 years 4 7.7 Females slightly predominated in the sample, accounting for 55.8% (n = 29) compared to males at 44.2% (n = 23). The majority of patients were young adults, with those aged 20–39 years constituting 86.5% (n = 45) of the total sample. The relationship between impacted third molar angulation and ERR is summarized in Table 2 . Table 2 Frequency Distribution of Affected Teeth and Relationship between Tooth Position and Angle(N = 69) Tooth Number Frequency Percentage (%) | Mean Angle (°) Deviation (SD) (°) 17 2 2.9 19.2 - 27 4 5.8 101.1 38.5 37 32 46.4 75.8 15.2 47 31 44.9 68.4 18.6 The mean angulations of tooth 37 (associated with tooth 38) and tooth 47 (associated with tooth 48) were comparable (75.8° and 68.4°, respectively). However, tooth 47 exhibited higher variability (SD = 18.6°) compared to tooth 37 (SD = 15.2°) (Table 2 , Fig. 1 ).Tooth 27 exhibited a significantly higher mean angulation (101.1°), which may be associated with maxillary impaction, supported by an increased prevalence of complete bony impaction in this position. ANOVA revealed a significant difference in mean angles among the different tooth positions (p < 0.05). The Tukey HSD post-hoc test revealed no significant difference in the mean angle between 37 and 47 (p = 0.12). Analysis of ERR revealed that mandibular second molars were the most commonly affected(Fig. 2 ). The severity of resorption varied, with 53% of cases reaching the pulp chamber and 30% confined to the superficial or deep dentin layers. The majority of ERR lesions (49.3%) were found in the apical third of the root (Table 3 ), and 24.6%(16/69) exhibited communication with the oral cavity. Of the 59 mandibular impacted third molars, 96.6% were classified as low-level impactions. All impacted maxillary third molars were classified as high-level impactions. Overall, 38% of these impacted third molars (both mandibular and maxillary) were completely encased in bone. (Fig. 3 ). A statistically significant association was found between complete bone impaction and ERR extending to the pulp chamber (52%, p < 0.05). Furthermore, communication of the ERR (5/5) (Figure.4)with the oral cavity resulted in a significantly higher incidence of pain on percussion. Younger patients demonstrated a greater likelihood of experiencing severs ERR that extended to the pulp chamber. Table 3 Characteristics of Second Molar External Root Resorption Location of Resorption Number of Cases Percentage Main Associated Features Apical 1/3 34 49.28% Full bony impaction n = 19 Partial impaction n = 14 Soft tissue coverage n = 1 Middle 1/3 25 36.23% Full bony impaction n = 5 Partial impaction n = 19 Soft tissue coverage n = 1 Cervical 1/3 10 14.49% Full bony impaction n = 1 Partial impaction n = 5 Soft tissue coverage n = 4 Pulp stones were found in a total of 15 affected teeth(Fig. 5 ). The analysis of distal periodontal pocket depth (PD) of the second molar in relation to the severity of ERR demonstrated a distinct trend (Table 4 ). Table 4 Association between Probing Depth (PD) and Severity of External Resorption PD (mm) Resorption into pulp (n = 36) Resorption into middle/deep dentin (n = 20) Resorption into superficial dentin (n = 13) 1–3 12 (33.3%) 10 (50%) 10 (76.9%) 4–6 14 (38.9%) 8 (40%) 3 (23.1%) ≥ 7 10 (27.8%) 2 (10%) 0 (0%) There was a statistically significant association between the severity of external root resorption and periodontal pocket depth, as determined by a Chi-Squared test (χ²(4) = 10.88, p = 0.028). Discussion Impacted teeth are those that fail to fully erupt into the dental arch due to obstruction by adjacent teeth, bone, or soft tissue . The mandibular third molar is the most commonly impacted tooth . Impacted mandibular third molars frequently cause ERR of adjacent second molars due to their often abnormal position and eruption path . This study demonstrates that the position of impacted third molars significantly influences the development and severity of ERR in adjacent second molars. Patient age emerged as a notable factor influencing ERR presentation. The majority of our cohort comprised young adults (20–30 years old). In this younger group, resorption extending to the pulp cavity was significantly more frequent compared to older patients ( p < 0.01). This increased propensity for deeper and potentially faster resorption in younger individuals may be attributable to more active bone metabolism and remodeling processes occurring during the typical third molar eruption/impaction period. Conversely, in the few older patients studied (≥ 50 years, n = 4), ERR was predominantly limited to superficial dentin. This might reflect reduced eruptive forces of the impacted tooth or increased bone density associated with aging . These age-related differences emphasize the need to consider patient age when assessing risk and developing monitoring strategies. Enamel is derived from the ectoderm, while dentin and cementum are derived from the mesoderm . Due to the presence of an intact junctional epithelium separating them, enamel and alveolar bone do not integrate . Clinical symptoms like pain only manifest when bacteria infiltrate the area of external resorption between the second and third molars, causing an infection. Consequently, the majority of completely bone-impacted cases remain asymptomatic . A critical finding is the often insidious nature of ERR. Only 4.3% of patients presented with pain on occlusion, highlighting that significant resorption can occur without overt symptoms. Notably, all cases exhibiting pain involved communication between the resorption defect and the oral cavity, strongly suggesting secondary infection as the primary cause of pain. This underscores the critical role of advanced imaging, particularly CBCT, for early and accurate diagnosis before symptoms arise or resorption becomes extensive . CBCT's ability to provide detailed three-dimensional visualization allows for precise assessment of the resorption's location, extent, and severity, as well as the exact relationship between the impacted and affected teeth – information often ambiguous on conventional radiographs . When infection is present (indicated by pain and oral communication), infection control measures are a necessary prerequisite before definitive treatment decisions are made. Pulp stones, defined as calcifications within the dental pulp , were frequently observed in cases where resorption was confined to superficial dentin. This may represent a calcific defensive response by the pulp to the chronic irritation stimulus . However, careful differential diagnosis is required to distinguish these from caries-related tertiary dentin or other pulpal pathologies. The prognostic implications of these findings are significant. CBCT identification of high-risk impaction patterns (e.g., deep, bony, specific angulations, close proximity) enables clinicians to predict ERR potential. Our data indicated that resorption progression rates were nearly double in cases with deep impactions compared to superficial ones. This, combined with the higher propensity for rapid resorption in younger patients, emphasizes the need for regular monitoring in at-risk individuals. A positive correlation exists between the severity of root resorption and periodontal pocket depth. Increasing resorption depth towards the pulp corresponds with a greater likelihood of deeper pockets. While a notable portion (33.3%) still had shallow PDs (1–3 mm), the highest proportion (38.9%) was found in the 4–6 mm PD range.Importantly, a significant percentage (27.8%) of cases with pulpal resorption had deep probing depths (≥ 7 mm). This suggests advanced resorption is a risk indicator for periodontal breakdown, potentially because the resulting communication pathway, especially with pulpal involvement, allows bacterial ingress and inflammation to spread into the periodontal ligament, fostering pocket development . Although primarily an association, inflammation from existing pockets might also worsen resorption. The sharp rise in deep pockets (≥ 7 mm) when resorption involves the pulp indicates this may be a critical threshold for significant periodontal deterioration. Given that pulpal involvement occurs in 60% of cases, a thorough assessment of pulp status is essential when determining treatment. Management strategies can vary from monitoring (for minimal, non-progressing superficial resorption) to endodontic therapy (if the pulp is compromised but the tooth is salvageable), or extraction of either the third molar, the second molar, or both. The clinical relevance of this evaluation lies in its direct impact on these complex therapeutic choices. Prophylactic removal of high-risk impacted third molars, especially in younger patients with CBCT evidence of significant root contact or early resorption, may be justified to prevent irreversible damage to the second molar . However, this must always be balanced against surgical risks. A conservative monitoring approach may suffice for low-risk cases. These findings strongly advocate for a tailored, patient-specific management strategy integrating radiographic (CBCT), clinical, and demographic factors. The lack of molecular or histological data limits our understanding of the cellular mechanisms driving resorption in these cases. Future studies incorporating biomarkers of inflammation or osteoclast activity—such as RANKL, IL-6, or MMP-9 levels—could provide a more comprehensive view of the biological processes involved and refine prognostic models . In conclusion, this study elucidates key prognostic factors influencing ERR of second molars adjacent to impacted third molars, including impaction angulation, depth, patient age, and periodontal status. These elements collectively shape the trajectory of resorption and underscore the need for advanced diagnostic tools and personalized management plans in dental practice. This study provides data supporting early clinical diagnosis and treatment strategies, but further validation is needed through prospective studies. Limitations Potential limitations of the methodology include the retrospective design, which may introduce selection bias. Additionally, the study did not include molecular or histological analyses due to resource constraints. Declarations Competing Interests The authors have no relevant financial or non-financial interests to disclose. Funding This work was supported by Program for New Clinical Techniques and Therapies of Peking University School and Hospital of Stomatology, PKUSSNKP-202120 Author Contribution 1.Kan Wang and Xiaoming Lyu designed this research. Kan Wang and Xiaoming Lyu are co-corresponding authors.2.Kan Wang and Jiajia Zheng collected data and wrote the main manuscript. Kan Wang and Jiajia Zheng contributed equally.3.Jinghua He prepared all figures and tables.4.Yuan Fu conducted statistical analysis.5.All authors reviewed the manuscript. Data Availability All data were from clinical records and imaging examination of Peking University Hospital of Stomatology, Due to ethical restrictions, the raw data cannot be made publicly available. However, de-identified data may be obtained from the corresponding author upon reasonable request. References Lima, T. C. D. S., Amaro, R. 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Cite Share Download PDF Status: Published Journal Publication published 10 Sep, 2025 Read the published version in Oral and Maxillofacial Surgery → Version 1 posted Editorial decision: Revision requested 06 Jul, 2025 Reviews received at journal 05 Jul, 2025 Reviews received at journal 25 Jun, 2025 Reviewers agreed at journal 17 Jun, 2025 Reviewers agreed at journal 16 Jun, 2025 Reviewers invited by journal 15 Jun, 2025 Editor assigned by journal 05 Jun, 2025 Submission checks completed at journal 05 Jun, 2025 First submitted to journal 27 May, 2025 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. We do this by developing innovative software and high quality services for the global research community. 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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-6759855","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":471760439,"identity":"8d8ffaa0-ad9c-45ad-b2b6-2e78306d867e","order_by":0,"name":"Kan Wang","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Kan","middleName":"","lastName":"Wang","suffix":""},{"id":471760440,"identity":"239f8dbe-1d7f-4aa3-9c11-493a883c0a1d","order_by":1,"name":"Jiajia Zheng","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Jiajia","middleName":"","lastName":"Zheng","suffix":""},{"id":471760441,"identity":"7df8baf3-6b72-4286-99ca-cc883e52de3b","order_by":2,"name":"Jinghua He","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Jinghua","middleName":"","lastName":"He","suffix":""},{"id":471760442,"identity":"213da715-bd69-4b7c-84a9-03d9aa7bca89","order_by":3,"name":"Yuan Fu","email":"","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":false,"prefix":"","firstName":"Yuan","middleName":"","lastName":"Fu","suffix":""},{"id":471760443,"identity":"5e150d2a-2365-4973-8748-a9d9044447b6","order_by":4,"name":"Xiaoming Lyu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIiWNgGAWjYBACPiA2/sMjwcPPzJD4IKGihrAWNiAu4JGxkZNsZ3hs8ODMMeK0fOCxSTM2OM/4TPJhCzMRWiSyEzdI5BxO3HCYOa0isYGNgb+9OwG/Fp6zmw0MzhxOnHmYLe1G4g4ZBokzZzfg18Leu80gsedwYt9hHqCWM2wMBhK5BLQw827/cfDf4cSGw/zfChLbmInQwt67wbCBJ81Y4DBDGgNxWnjObjBm4AEGcjNDskTCmWM8BP3CDzQTqAUYlfwHEj/+qKiR42/vxa8FA/CQpnwUjIJRMApGAVYAAO02SH+vHMDlAAAAAElFTkSuQmCC","orcid":"","institution":"Peking University School and Hospital of Stomatology","correspondingAuthor":true,"prefix":"","firstName":"Xiaoming","middleName":"","lastName":"Lyu","suffix":""}],"badges":[],"createdAt":"2025-05-27 13:23:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6759855/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6759855/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10006-025-01436-1","type":"published","date":"2025-09-10T15:57:04+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":84872869,"identity":"7f1d1fed-ba71-4d81-a055-119010590394","added_by":"auto","created_at":"2025-06-18 09:17:40","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":401718,"visible":true,"origin":"","legend":"\u003cp\u003ea.The angle between the long axes of 17 (associated with tooth 18) at the location of ERR. b. The angle between the long axes of 27 (associated with tooth 28) at the location of ERR. c. The angle between the long axes of 47 (associated with tooth 48) at the location of ERR.d. The angle between the long axes of 37 (associated with tooth 38) at the location of ERR.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6759855/v1/d175f4dac22dd5fcef0f99e6.png"},{"id":84872870,"identity":"d4386fc5-8bcf-47d5-88ca-5a291ebe1827","added_by":"auto","created_at":"2025-06-18 09:17:40","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":179254,"visible":true,"origin":"","legend":"\u003cp\u003ea. Mild ERR: Root resorption is less than half the root canal wall thickness.b. Moderate ERR: Root resorption exceeds half the root canal wall thickness but does not involve the root canal system.c. Severe ERR: Root resorption involves the root canal system.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6759855/v1/585b2e74b119a1db8da10209.png"},{"id":84872873,"identity":"db6f7b05-085e-488a-a92f-41aa26991886","added_by":"auto","created_at":"2025-06-18 09:17:40","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":196473,"visible":true,"origin":"","legend":"\u003cp\u003ea. ERR due to completely impacted third molar.b. ERR due to partially impacted third molar.c. ERR due to impacted third molar (without bony impaction).\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6759855/v1/725422cb2952852fffe2f78e.png"},{"id":84872868,"identity":"104e4700-83b1-437f-8761-4df699ca9d20","added_by":"auto","created_at":"2025-06-18 09:17:40","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":15763,"visible":true,"origin":"","legend":"\u003cp\u003eThe location of ERR is communicated with the oral cavity, the translucent area is visible at the root furcation of mandile second molar.\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6759855/v1/961a87464e4c91168b98e093.jpeg"},{"id":84872875,"identity":"c4b9de0f-625c-40cc-97c6-c157dc85acf3","added_by":"auto","created_at":"2025-06-18 09:17:40","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":17712,"visible":true,"origin":"","legend":"\u003cp\u003eERR extending into the root canal with pulp stone visible in the pulp chamber\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6759855/v1/3ac64cad74c119f702c6168a.jpeg"},{"id":91358977,"identity":"75755d8e-d7a6-4f62-a298-944b18424543","added_by":"auto","created_at":"2025-09-15 16:02:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1402946,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6759855/v1/04d88f84-287d-4e72-83d4-b6763a6c68df.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"External Root Resorption of Second Molars Caused by Impacted Third Molars: CBCT characteristics","fulltext":[{"header":"Introduction","content":"\u003cp\u003eExternal root resorption (ERR) is a pathological condition characterized by the progressive loss of dental root structure due to the activity of odontoclasts, often triggered by mechanical pressure, inflammation, or trauma\u003ca class=\"FNLink\" href=\"#Fn1\" id=\"#FNLinkFn1\"\u003e\u003c/a\u003e. Among the various etiologies, the impaction of third molars has been recognized as a significant contributing factor to ERR in adjacent second molars\u003ca class=\"FNLink\" href=\"#Fn2\" id=\"#FNLinkFn2\"\u003e\u003c/a\u003e. Impacted third molars, due to their abnormal position or lack of space for proper eruption, can exert sustained pressure on the roots of neighboring teeth, leading to resorption over time\u003ca class=\"FNLink\" href=\"#Fn3\" id=\"#FNLinkFn3\"\u003e\u003c/a\u003e. In the adult population, the overall incidence of impacted teeth is approximately 20%, with mandibular third molars being the most commonly impacted\u003ca class=\"FNLink\" href=\"#Fn4\" id=\"#FNLinkFn4\"\u003e\u003c/a\u003e. This phenomenon compromises the structural integrity of affected second molars, with significant long-term consequences such as reduced tooth stability, increased risk of periodontal complications, and potential tooth loss.\u003c/p\u003e \u003cp\u003eThe prognosis of second molars affected by ERR from impacted third molars is of critical concern to dentists. While some cases of resorption may remain asymptomatic and undetected until advanced stages, others can progress rapidly, necessitating complex interventions such as tooth extraction\u003ca class=\"FNLink\" href=\"#Fn5\" id=\"#FNLinkFn5\"\u003e\u003c/a\u003e. The heterogeneity in the progression and clinical outcomes of ERR necessitates a comprehensive understanding of relevant prognostic indicators. These include the degree of third molar impaction\u003ca class=\"FNLink\" href=\"#Fn6\" id=\"#FNLinkFn6\"\u003e\u003c/a\u003e, the three-dimensional spatial relationship with the adjacent second molar, in particular, the presence of communication between the external resorption site and the oral cavity, and patient-specific variables such as age and overall health status. Identification and accurate risk stratification for ERR are critical for informed clinical decision-making, facilitating both prophylactic strategies and therapeutic interventions aimed at preserving the functional integrity and long-term viability of the second molar\u003ca class=\"FNLink\" href=\"#Fn7\" id=\"#FNLinkFn7\"\u003e\u003c/a\u003e.\u003c/p\u003e \u003cp\u003eWhile Cone-beam computed tomography (CBCT) enhances the assessment of anatomical relationships between impacted third molars and adjacent second molars, a lack of large-scale radiographic studies limits our understanding of the natural of ERR\u003ca class=\"FNLink\" href=\"#Fn8\" id=\"#FNLinkFn8\"\u003e\u003c/a\u003e. Since ERR is frequently asymptomatic\u003ca class=\"FNLink\" href=\"#Fn9\" id=\"#FNLinkFn9\"\u003e\u003c/a\u003e, this study utilizes CBCT to investigate its characteristics in second molars adjacent to impacted third molars. By analyzing CBCT findings from clinical cases, we aim to evaluate the severity of resorption. The primary goal is to identify key predictors, thereby generating evidence-based insights to enhance risk stratification and guide clinical decision-making regarding impacted third molars.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eEthics Statement\u003c/h2\u003e \u003cp\u003e This study was approved by the Ethics Committee of Peking University School and Hospital of Stomatology (approval number: PKUSSIRB-202165092) and was registed on National Health Security Information Platform by National Health Commission of People\u0026rsquo;s Republic of China (pid:263774).\u003c/p\u003e \u003cp\u003e Patients were consented by an informed consent process that was reviewed by the Ethics Committee of Peking University School and Hospital of Stomatology and certify that the study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStudy Population\u003c/h3\u003e\n\u003cp\u003e This retrospective study reviewed patients diagnosed with ERR between September 2021 and September 2024, selected from the dental records of the Second Clinical Division, Peking University School and Hospital of Stomatology. Data were collected on patient demographics (age and gender), the site of ERR and associated clinical symptoms, clinical examination findings (mobility of the affected tooth, probing depth (PD), percussion response, pulp vitality tests, and presence of communication with the oral cavity), and radiographic outcomes. Using CBCT, the location of maximum root resorption on the second molar was determined. Imaging parameters included a voltage of 90 kV, a current of 6 mA, an exposure time of 16 seconds, and a slice thickness of 0.125 mm.\u003c/p\u003e \u003cp\u003eThe maximum cross-sectional plane at this level was obtained. Within this plane, the long axes of the second and third molars were delineated. The angle between these two axes was calculated, with the measurement oriented toward the direction of external root resorption.\u003c/p\u003e \u003cp\u003eInclusion criteria were as follows: (1) presence of at least one impacted third molar in contact with the adjacent second molar, (2) CBCT evidence of ERR on the second molar; Exclusion criteria included: (1) history of orthodontic treatment involving the affected teeth, (2) prior surgical intervention on the third molar, and (3) incomplete clinical or radiographic records.\u003c/p\u003e \u003cp\u003eCBCT scans were analyzed to record the following parameters for each case:\u003c/p\u003e \u003cp\u003e(1)Angulation of the impacted third molar.\u003c/p\u003e \u003cp\u003e(2) Depth of associated root resorption on the second molar (superficial, at the cementoenamel junction [CEJ], or apical to the CEJ).\u003c/p\u003e \u003cp\u003e(3) Degree of impaction (partial or full).\u003c/p\u003e \u003cp\u003e(4)ERR Severity: Mild ERR, root resorption does not exceed half of the root canal wall thickness. Moderate ERR, root resorption has exceeded half of the root canal wall thickness but not yet involved the root cannal system. Severe ERR, root resorption involves the root cannal system.\u003c/p\u003e \u003cp\u003eCBCT images were analyzed using SmartVPro version 2.0 by two independent examiners blinded to patient details. The relationship between the impacted third molar and the second molar root was evaluated in three dimensions (axial, coronal, and sagittal planes). ERR was quantified by measuring the length of the resorbed root segment relative to the total root length from the cementoenamel junction to the apex.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eData were analyzed using SPSS version 26.0. Descriptive statistics (means, standard deviations, and percentages) were used to summarize patient characteristics, impaction patterns, and ERR severity. The association between prognostic factors (e.g., impaction angulation, depth, age, and periodontal status) and ERR progression was assessed using chi-square tests for categorical variables and independent t-tests or ANOVA for continuous variables. Multivariate logistic regression was employed to identify independent predictors of severe ERR (Cervical 1/3), with odds ratios (OR) and 95% confidence intervals (CI) calculated. A p-value of \u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThis study analyzed 69 second molars with diagnosed external root resorption (ERR) across 52 patients. Radiographic confirmation established that ERR in all cases was associated with adjacent impacted third molars.\u003c/p\u003e \u003cp\u003ePatient demographic characteristics are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The age range of the patients was 22\u0026ndash;59 years, with an average age of 31.2 years.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePatient demographic characteristics(N\u0026thinsp;=\u0026thinsp;52)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNumber\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePercentage%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e44.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e55.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge Group\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u0026ndash;29 years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e44.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u0026ndash;39 years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e42.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40\u0026ndash;49 years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e50\u0026ndash;59 years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFemales slightly predominated in the sample, accounting for 55.8% (n\u0026thinsp;=\u0026thinsp;29) compared to males at 44.2% (n\u0026thinsp;=\u0026thinsp;23). The majority of patients were young adults, with those aged 20\u0026ndash;39 years constituting 86.5% (n\u0026thinsp;=\u0026thinsp;45) of the total sample.\u003c/p\u003e \u003cp\u003eThe relationship between impacted third molar angulation and ERR is summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eFrequency Distribution of Affected Teeth and Relationship between Tooth Position and Angle(N\u0026thinsp;=\u0026thinsp;69)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTooth Number\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFrequency\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePercentage (%) |\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMean Angle (\u0026deg;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eDeviation (SD) (\u0026deg;)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e19.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e101.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e38.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e75.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e44.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e68.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e18.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe mean angulations of tooth 37 (associated with tooth 38) and tooth 47 (associated with tooth 48) were comparable (75.8\u0026deg; and 68.4\u0026deg;, respectively). However, tooth 47 exhibited higher variability (SD\u0026thinsp;=\u0026thinsp;18.6\u0026deg;) compared to tooth 37 (SD\u0026thinsp;=\u0026thinsp;15.2\u0026deg;) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).Tooth 27 exhibited a significantly higher mean angulation (101.1\u0026deg;), which may be associated with maxillary impaction, supported by an increased prevalence of complete bony impaction in this position.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eANOVA revealed a significant difference in mean angles among the different tooth positions (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The Tukey HSD post-hoc test revealed no significant difference in the mean angle between 37 and 47 (p\u0026thinsp;=\u0026thinsp;0.12).\u003c/p\u003e \u003cp\u003eAnalysis of ERR revealed that mandibular second molars were the most commonly affected(Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The severity of resorption varied, with 53% of cases reaching the pulp chamber and 30% confined to the superficial or deep dentin layers. The majority of ERR lesions (49.3%) were found in the apical third of the root (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), and 24.6%(16/69) exhibited communication with the oral cavity. Of the 59 mandibular impacted third molars, 96.6% were classified as low-level impactions. All impacted maxillary third molars were classified as high-level impactions. Overall, 38% of these impacted third molars (both mandibular and maxillary) were completely encased in bone. (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). A statistically significant association was found between complete bone impaction and ERR extending to the pulp chamber (52%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Furthermore, communication of the ERR (5/5) (Figure.4)with the oral cavity resulted in a significantly higher incidence of pain on percussion. Younger patients demonstrated a greater likelihood of experiencing severs ERR that extended to the pulp chamber.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristics of Second Molar External Root Resorption\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocation of Resorption\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNumber of Cases\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePercentage\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMain Associated Features\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eApical 1/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e49.28%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFull bony impaction n\u0026thinsp;=\u0026thinsp;19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePartial impaction n\u0026thinsp;=\u0026thinsp;14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSoft tissue coverage n\u0026thinsp;=\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eMiddle 1/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e36.23%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFull bony impaction n\u0026thinsp;=\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePartial impaction n\u0026thinsp;=\u0026thinsp;19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSoft tissue coverage n\u0026thinsp;=\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eCervical 1/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e14.49%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFull bony impaction n\u0026thinsp;=\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePartial impaction n\u0026thinsp;=\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSoft tissue coverage n\u0026thinsp;=\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003ePulp stones were found in a total of 15 affected teeth(Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe analysis of distal periodontal pocket depth (PD) of the second molar in relation to the severity of ERR demonstrated a distinct trend (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAssociation between Probing Depth (PD) and Severity of External Resorption\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePD (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eResorption into pulp (n\u0026thinsp;=\u0026thinsp;36)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eResorption into middle/deep dentin (n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eResorption into superficial dentin (n\u0026thinsp;=\u0026thinsp;13)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u0026ndash;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e12 (33.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10 (76.9%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u0026ndash;6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14 (38.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (40%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (23.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10 (27.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThere was a statistically significant association between the severity of external root resorption and periodontal pocket depth, as determined by a Chi-Squared test (χ\u0026sup2;(4)\u0026thinsp;=\u0026thinsp;10.88, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.028).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eImpacted teeth are those that fail to fully erupt into the dental arch due to obstruction by adjacent teeth, bone, or soft tissue\u003ca class=\"FNLink\" href=\"#Fn10\" id=\"#FNLinkFn10\"\u003e\u003c/a\u003e. The mandibular third molar is the most commonly impacted tooth\u003ca class=\"FNLink\" href=\"#Fn11\" id=\"#FNLinkFn11\"\u003e\u003c/a\u003e. Impacted mandibular third molars frequently cause ERR of adjacent second molars due to their often abnormal position and eruption path\u003ca class=\"FNLink\" href=\"#Fn12\" id=\"#FNLinkFn12\"\u003e\u003c/a\u003e. This study demonstrates that the position of impacted third molars significantly influences the development and severity of ERR in adjacent second molars.\u003c/p\u003e \u003cp\u003ePatient age emerged as a notable factor influencing ERR presentation. The majority of our cohort comprised young adults (20\u0026ndash;30 years old). In this younger group, resorption extending to the pulp cavity was significantly more frequent compared to older patients (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). This increased propensity for deeper and potentially faster resorption in younger individuals \u003ca class=\"FNLink\" href=\"#Fn13\" id=\"#FNLinkFn13\"\u003e\u003c/a\u003emay be attributable to more active bone metabolism and remodeling processes occurring during the typical third molar eruption/impaction period. Conversely, in the few older patients studied (\u0026ge;\u0026thinsp;50 years, n\u0026thinsp;=\u0026thinsp;4), ERR was predominantly limited to superficial dentin. This might reflect reduced eruptive forces of the impacted tooth or increased bone density associated with aging\u003ca class=\"FNLink\" href=\"#Fn14\" id=\"#FNLinkFn14\"\u003e\u003c/a\u003e. These age-related differences emphasize the need to consider patient age when assessing risk and developing monitoring strategies.\u003c/p\u003e \u003cp\u003eEnamel is derived from the ectoderm, while dentin and cementum are derived from the mesoderm\u003ca class=\"FNLink\" href=\"#Fn15\" id=\"#FNLinkFn15\"\u003e\u003c/a\u003e. Due to the presence of an intact junctional epithelium separating them, enamel and alveolar bone do not integrate\u003ca class=\"FNLink\" href=\"#Fn16\" id=\"#FNLinkFn16\"\u003e\u003c/a\u003e. Clinical symptoms like pain only manifest when bacteria infiltrate the area of external resorption between the second and third molars, causing an infection. Consequently, the majority of completely bone-impacted cases remain asymptomatic\u003ca class=\"FNLink\" href=\"#Fn17\" id=\"#FNLinkFn17\"\u003e\u003c/a\u003e.\u003c/p\u003e \u003cp\u003eA critical finding is the often insidious nature of ERR. Only 4.3% of patients presented with pain on occlusion, highlighting that significant resorption can occur without overt symptoms. Notably, all cases exhibiting pain involved communication between the resorption defect and the oral cavity, strongly suggesting secondary infection as the primary cause of pain. This underscores the critical role of advanced imaging, particularly CBCT, for early and accurate diagnosis before symptoms arise or resorption becomes extensive\u003ca class=\"FNLink\" href=\"#Fn18\" id=\"#FNLinkFn18\"\u003e\u003c/a\u003e. CBCT's ability to provide detailed three-dimensional visualization allows for precise assessment of the resorption's location, extent, and severity, as well as the exact relationship between the impacted and affected teeth \u0026ndash; information often ambiguous on conventional radiographs\u003ca class=\"FNLink\" href=\"#Fn19\" id=\"#FNLinkFn19\"\u003e\u003c/a\u003e. When infection is present (indicated by pain and oral communication), infection control measures are a necessary prerequisite before definitive treatment decisions are made.\u003c/p\u003e \u003cp\u003ePulp stones, defined as calcifications within the dental pulp\u003ca class=\"FNLink\" href=\"#Fn20\" id=\"#FNLinkFn20\"\u003e\u003c/a\u003e, were frequently observed in cases where resorption was confined to superficial dentin. This may represent a calcific defensive response by the pulp to the chronic irritation stimulus\u003ca class=\"FNLink\" href=\"#Fn21\" id=\"#FNLinkFn21\"\u003e\u003c/a\u003e. However, careful differential diagnosis is required to distinguish these from caries-related tertiary dentin or other pulpal pathologies.\u003c/p\u003e \u003cp\u003eThe prognostic implications of these findings are significant. CBCT identification of high-risk impaction patterns (e.g., deep, bony, specific angulations, close proximity) enables clinicians to predict ERR potential. Our data indicated that resorption progression rates were nearly double in cases with deep impactions compared to superficial ones. This, combined with the higher propensity for rapid resorption in younger patients, emphasizes the need for regular monitoring in at-risk individuals.\u003c/p\u003e \u003cp\u003eA positive correlation exists between the severity of root resorption and periodontal pocket depth. Increasing resorption depth towards the pulp corresponds with a greater likelihood of deeper pockets. While a notable portion (33.3%) still had shallow PDs (1\u0026ndash;3 mm), the highest proportion (38.9%) was found in the 4\u0026ndash;6 mm PD range.Importantly, a significant percentage (27.8%) of cases with pulpal resorption had deep probing depths (\u0026ge;\u0026thinsp;7 mm). This suggests advanced resorption is a risk indicator for periodontal breakdown, potentially because the resulting communication pathway, especially with pulpal involvement, allows bacterial ingress and inflammation to spread into the periodontal ligament, fostering pocket development\u003ca class=\"FNLink\" href=\"#Fn22\" id=\"#FNLinkFn22\"\u003e\u003c/a\u003e. Although primarily an association, inflammation from existing pockets might also worsen resorption. The sharp rise in deep pockets (\u0026ge;\u0026thinsp;7 mm) when resorption involves the pulp indicates this may be a critical threshold for significant periodontal deterioration.\u003c/p\u003e \u003cp\u003eGiven that pulpal involvement occurs in 60% of cases, a thorough assessment of pulp status is essential when determining treatment. Management strategies can vary from monitoring (for minimal, non-progressing superficial resorption) to endodontic therapy (if the pulp is compromised but the tooth is salvageable), or extraction of either the third molar, the second molar, or both. The clinical relevance of this evaluation lies in its direct impact on these complex therapeutic choices. Prophylactic removal of high-risk impacted third molars, especially in younger patients with CBCT evidence of significant root contact or early resorption, may be justified to prevent irreversible damage to the second molar\u003ca class=\"FNLink\" href=\"#Fn23\" id=\"#FNLinkFn23\"\u003e\u003c/a\u003e. However, this must always be balanced against surgical risks. A conservative monitoring approach may suffice for low-risk cases. These findings strongly advocate for a tailored, patient-specific management strategy integrating radiographic (CBCT), clinical, and demographic factors.\u003c/p\u003e \u003cp\u003eThe lack of molecular or histological data limits our understanding of the cellular mechanisms driving resorption in these cases. Future studies incorporating biomarkers of inflammation or osteoclast activity\u0026mdash;such as RANKL, IL-6, or MMP-9 levels\u0026mdash;could provide a more comprehensive view of the biological processes involved and refine prognostic models\u003ca class=\"FNLink\" href=\"#Fn24\" id=\"#FNLinkFn24\"\u003e\u003c/a\u003e.\u003c/p\u003e \u003cp\u003eIn conclusion, this study elucidates key prognostic factors influencing ERR of second molars adjacent to impacted third molars, including impaction angulation, depth, patient age, and periodontal status. These elements collectively shape the trajectory of resorption and underscore the need for advanced diagnostic tools and personalized management plans in dental practice. This study provides data supporting early clinical diagnosis and treatment strategies, but further validation is needed through prospective studies.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003ePotential limitations of the methodology include the retrospective design, which may introduce selection bias. Additionally, the study did not include molecular or histological analyses due to resource constraints.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting Interests\u003c/h2\u003e \u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis work was supported by Program for New Clinical Techniques and Therapies of Peking University School and Hospital of Stomatology, PKUSSNKP-202120\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003e1.Kan Wang and Xiaoming Lyu designed this research. Kan Wang and Xiaoming Lyu are co-corresponding authors.2.Kan Wang and Jiajia Zheng collected data and wrote the main manuscript. Kan Wang and Jiajia Zheng contributed equally.3.Jinghua He prepared all figures and tables.4.Yuan Fu conducted statistical analysis.5.All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eAll data were from clinical records and imaging examination of Peking University Hospital of Stomatology, Due to ethical restrictions, the raw data cannot be made publicly available. However, de-identified data may be obtained from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003e Lima, T. C. D. S., Amaro, R. G., Dos Santos, L. C. M., Coste, S. C., Silva, E. F. E., Barbato-Ferreira, D. A., Colosimo, E. A., Silva, T. A. D., \u0026amp; Bastos, J. V. (2021). 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TNF-α-TNFR1 Signaling Mediates Inflammation and Bone Resorption in Apical Periodontitis.\u0026nbsp;\u003cem\u003eJournal of endodontics\u003c/em\u003e,\u0026nbsp;\u003cem\u003e49\u003c/em\u003e(10), 1319\u0026ndash;1328.e2. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.joen.2023.07.013\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2023.07.013\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\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":"oral-and-maxillofacial-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"omfs","sideBox":"Learn more about [Oral and Maxillofacial Surgery](http://link.springer.com/journal/10006)","snPcode":"10006","submissionUrl":"https://submission.nature.com/new-submission/10006/3","title":"Oral and Maxillofacial Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"cone-beam computed tomography (CBCT), External root resorption (ERR), second molar, impacted third molar","lastPublishedDoi":"10.21203/rs.3.rs-6759855/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6759855/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eObjectives\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThis study aims to describe the cone-beam computed tomography (CBCT) characteristics of external root resorption (ERR) in second molars associated with impacted third molars.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThis study analyzed 69 second molars diagnosed with ERR caused by impacted third molars in 52 patients (age range: 22\u0026ndash;59 years; mean age\u0026thinsp;=\u0026thinsp;31.2\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1 years) to identify key factors influencing the severity and occurrence of ERR. CBCT was used to assess the relationship between impacted third molar characteristics (position, angulation, proximity) and the extent of root resorption in adjacent second molars.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003eERR most commonly affected mandibular second molars (37 teeth: 60.0%, 47 teeth: 40.6%). Resorption extended to the pulp chamber in 47.9% of cases, while 40.6% was limited to superficial/middle dentin. 24.6% of the ERR sites were in communication with the oral cavity. Eighty-four cases of third molars were associated with external resorption of the second molars.87% of impacted third molars were low-level, and 38% were completely bone-impacted. 26% had an angulation\u0026thinsp;\u0026gt;\u0026thinsp;90\u0026deg; relative to the affected tooth. Complete bone impaction significantly correlated with ERR extending to the pulp chamber (65%, p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). ERR communicating with the oral cavity significantly increased pain on percussion. Younger patients were more likely to have ERR extending to the pulp chamber.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusions\u003c/b\u003e\u003c/p\u003e \u003cp\u003eLow-level and complete bone impactions of impacted third molars significantly contribute to the development of ERR in adjacent second molars. Communication between the ERR site and the oral cavity is associated with a high risk of infection.\u003c/p\u003e","manuscriptTitle":"External Root Resorption of Second Molars Caused by Impacted Third Molars: CBCT characteristics","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-18 09:17:36","doi":"10.21203/rs.3.rs-6759855/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-06T13:55:44+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-05T16:15:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-25T18:35:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"31169493486637799146080840863317142522","date":"2025-06-17T21:09:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"99775651001040089125653915813096554537","date":"2025-06-16T07:00:34+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-15T21:30:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-05T07:01:03+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-05T06:54:35+00:00","index":"","fulltext":""},{"type":"submitted","content":"Oral and Maxillofacial Surgery","date":"2025-05-27T13:14:11+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"oral-and-maxillofacial-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"omfs","sideBox":"Learn more about [Oral and Maxillofacial Surgery](http://link.springer.com/journal/10006)","snPcode":"10006","submissionUrl":"https://submission.nature.com/new-submission/10006/3","title":"Oral and Maxillofacial Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"65c05484-ac14-4a39-9b2f-9f1cfaf2f8f2","owner":[],"postedDate":"June 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-09-15T15:58:43+00:00","versionOfRecord":{"articleIdentity":"rs-6759855","link":"https://doi.org/10.1007/s10006-025-01436-1","journal":{"identity":"oral-and-maxillofacial-surgery","isVorOnly":false,"title":"Oral and Maxillofacial Surgery"},"publishedOn":"2025-09-10 15:57:04","publishedOnDateReadable":"September 10th, 2025"},"versionCreatedAt":"2025-06-18 09:17:36","video":"","vorDoi":"10.1007/s10006-025-01436-1","vorDoiUrl":"https://doi.org/10.1007/s10006-025-01436-1","workflowStages":[]},"version":"v1","identity":"rs-6759855","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6759855","identity":"rs-6759855","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}