Prevalence of external apical root resorption among orthodontic patients: a Cross-sectional study

Prevalence of external apical root resorption among orthodontic patients: 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 Prevalence of external apical root resorption among orthodontic patients: a Cross-sectional study Michael Francis, Tanya Al Talib, Neamat Hassan Abubakr This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7744427/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objectives With the increased demand for orthodontic treatments in adults, external apical root resorption (EARR) has always been an complication during orthodontic treatment. The present study aimed to investigate the presence of external apical root resorption (EARR) among orthodontics patients attending dental clinics at the School of Dental Medicine, University of Nevada, Las Vegas. Methods A retrospective keywords search of the clinical notes of UNLV School of Dental Medicine (SDM) patient charts in axiUm™ was performed using the search terms “orthodontics”, “root resorption”, and “external apical root resorption” to identify the number of orthodontic cases that clinically presented with EARR using the Levander & Malmgren ranking of the EARR levels. The inclusion criteria encompassed patients with previous orthodontic treatment, non-extraction cases, no congenital abnormalities, and no preexisting documented root resorption or endodontic treatment prior to the study. The patient population's inclusion criteria encompassed records of individuals who were ≥ 12 years. Results 148 patients presented with EARR, the Hispanic population had the most significant incidence of EARR (50%). Among all EARR cases, 59% were under the age of 18 yrs, followed by the age group 18–24 years (22%). Females comprised 60.8%, with males accounting for 39.2% of total cases. Most cases had a grade 2 EARR (64.2%) ranking as moderate resorption, while only 6.1% had a grade 4 EARR (Extreme resorption). Conclusion Within the limitations of the present investigation, the presence of EARR was dominant among young adult Hispanic females. Upper and lower anterior teeth exhibited more EARR with level 2, indicating moderate resorption. External apical root resorption EARR Orthodontics Prevalence Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction The demand for orthodontic treatment has increased markedly, largely owing to heightened patient motivation and greater dental health awareness, particularly among adults. As more patients are treated with fixed orthodontic appliances, the associated risks—such as caries, periodontal complications, and root resorption—become increasingly relevant. One such complication is external apical root resorption (EARR), a condition arising from the pathological or physiological activity of resorptive cells, which leads to loss of the root apex and consequent shortening or deformation of the root (Alqerban et al. 2009 ). EARR is a multifactorial and complex phenomenon, exhibiting variable severity among different patients and even among different teeth within the same individual. It is considered an undesirable outcome of orthodontic tooth movement. Several studies have found that much of the root resorption occurs during the first 6–9 months of treatment (Levander and Malmgren 1988 ). In fixed-appliance orthodontics, EARR is often viewed as an iatrogenic consequence. Numerous risk factors have been implicated, including malocclusion type, patient age, root morphology, dental anomalies, duration of treatment, and prior trauma (Weltman et al. 2010 ; Segal et al. 2004 ; Shahrure and Acar 2022 ; Nanekrungsan et al. 2012 ; Picanco et al. 2013 ). A positive association has been noted between higher orthodontic force levels and increased root resorption (Roscoe et al. 2015 ; Dawood et al. 2023 ). Orthodontic tooth movement itself has been estimated to account for one-tenth to one-third of the total variance in EARR (Roscoe et al. 2015 ). Significant reduction in root length can adversely affect the dentition, particularly when accompanied by alveolar bone loss (Roscoe et al. 2015 ). Genetic predisposition also plays a critical role in EARR susceptibility. Twin and association studies suggest that genetic factors account for a portion of the observed variation in post-orthodontic root resorption (Sharab et al. 2015 ; Pinheiro et al. 2021 ; Baghaei et al. 2023 ; Nieto-Nieto et al. 2017 ). A growing body of literature addresses the incidence, etiology, and management of EARR across diverse populations. The present study aims to evaluate the prevalence and characteristics of EARR among orthodontic patients treated at the UNLV School of Dental Medicine. Materials and Methods In the present cross-sectional study, clinical notes from patients at the University of Nevada, Las Vegas (UNLV) dental clinics were analyzed using AxiUm™ software. A search was conducted using the following keywords “orthodontics”, “root resorption”, and “external apical root resorption” to identify the number of orthodontic documented patients at SDM, UNLV. The inclusion criteria encompassed patients who had previous orthodontic treatment, non-extracted cases, no congenital abnormalities, no preexisting documented root resorption or endodontic treatment prior to the study. Figure 1, shows the demographics of the collected data. The MiPACS (Medical Imaging Picture Archiving and Communication System) is a comprehensive digital imaging system fully integrated with the axiUm™ dental software, and it was used for all examined radiographic. Figure 1: Descriptive data collection flowchart MiPACS is the primary imaging module for capturing, viewing, and managing dental radiographs such as intraoral radiographs, cephalometric, and panoramic images. MiPACS enhances clinical diagnostics with advanced image enhancement tools, including zoom, contrast adjustment, annotations, and measurement tools. The amount of EARR was evaluated using the Levander & Malmgren ranking of the EARR levels [figure 2] (Levander and Malmgren 1988). The ranking was as follows: Grade 0: Absence of root resorption; Grade 1: Mild resorption, root with its normal length, and only an irregular contour; Grade 2: Moderate resorption, small area of root loss with the apex exhibiting an almost straight contour; Grade 3: Accentuated resorption, loss of almost one third of root length; and Grade 4: Extreme resorption, loss of more than one third of the root length Figure 2: Levander & Malmgren EARR ranking levels [2] The Chi-square tests and One-Way ANOVA were used to analyses the results. The association between EAR grades and ethnicity cross tabulation was assessed using Pearson chi- squared test (SPSS version 28). Results 148 patients of Orthodontic patients of the SDM UNLV presented with EARR. Among all EARR cases, females comprised 60.8%, with males accounting for 39.2% of total cases. Results showed that Hispanics had the most significant incidence of EARR (50%) followed by mixed ethnicity (27%) while both Asian and African American had the least EARR (Figure 3). Figure 3: EARR distribution according to ethnicity Among all EARR cases, 59% occurred in individuals under the age of 18, followed by 22% in the 18–24 age group, 14% in the 25–34 age group, and 3% in the 35–44 age group. Patients aged 45 years and older accounted for less than 3% of EARR cases. The majority of cases were classified as Grade 2 EARR, while only 6.1% were categorized as Grade 4 EARR (Table 1). Sample cases of different grades of EARR are show in figure 4. Analysis using one-way ANOVA demonstrated a significant difference in the mean age among cases with different EARR grades. Cases with Grade 1 EARR exhibited the highest mean age, followed by Grades 2, 4, and 3, respectively (Table 1). Grade N (%) Mean Age (Years) ± SD P value Grade 1 20 (13.5%) 25.50 13.983 0.019* Grade 2 95 (64.2%) 19.35 8.896 Grade 3 24 (16.2%) 17.54 4.709 Grade 4 9 (6.1%) 17.56 4.096 *p < 0.05; Significant Table 1: EARR ranking level distributions Figure 4: Cases with different EARR grades. The Chi-Square test was employed to assess the distribution of various EARR grades across ethnicity, gender, and dental arch. The analysis revealed that the distribution of EARR grades differed significantly among ethnic groups. In contrast, no statistically significant differences were observed in the distribution of EARR grades concerning gender or dental arch (Table 2). Grade 1 Grade 2 Grade 3 Grade 4 P value N (%) N (%) N (%) N (%) Ethnicity African American 2 (66.7%) 1 (33.3%) - - 0.037* Asian - 2 (66.7%) - 1 (33.3%) Caucasian 6 (22.2%) 16 (59.3%) 4 (14.8%) 1 (3.7%) Hispanic 3 (4.1%) 52 (70.3%) 14 (18.9%) 5 (6.8%) Mixed 9 (22.0%) 24 (58.5%) 6 (14.6%) 2 (4.9%) Gender Female 13 (14.4%) 55 (61.1%) 17 (18.9%) 5 (5.6%) 0.659; NS Male 7 (12.1%) 40 (69.0%) 7 (12.1%) 4 (6.9%) Arch L 8 (19.5%) 23 (56.1%) 6 (14.6%) 4 (9.8%) 0.055; NS U 5 (23.8%) 16 (76.2%) - - U/L 7 (8.1%) 56 (65.1%) 18 (20.9%) 5 (5.8%) Chi-Square Test: NS: p > 0.05; Not significant; *p<0.05; Significant Table 2: Distribution of different EARR grades among ethnicity, gender and arch Pairwise comparisons of EARR grades among ethnic groups using the Chi-Square test indicated that statistically significant differences were present specifically between African American and Hispanic, Caucasian and Hispanic, and Hispanic and Mixed ethnicities (Table 3). Ethnicity Grade 1 N (%) Grade 2 N (%) Grade 3 N (%) Grade 4 N (%) P value African American Vs 2 (66.7%) 1 (33.3%) - - 0.189; NS Asian - 2 (66.7%) - 1 (33.3%) African American Vs 2 (66.7%) 1 (33.3%) - - 0.411; NS Caucasian 6 (22.2%) 16 (59.3%) 4 (14.8%) 1 (3.7%) African American Vs 2 (66.7%) 1 (33.3%) - - <0.001** Hispanic 3 (4.1%) 52 (70.3%) 14 (18.9%) 5 (6.8%) African American Vs 2 (66.7%) 1 (33.3%) - - 0.371; NS Mixed 9 (22.0%) 24 (58.5%) 6 (14.6%) 2 (4.9%) Asian Vs - 2 (66.7%) - 1 (33.3%) 0.196; NS Caucasian 6 (22.2%) 16 (59.3%) 4 (14.8%) 1 (3.7%) Asian Vs - 2 (66.7%) - 1(33.3%) 0.347; NS Hispanic 3 52 (70.3% 14 (18.9%) 5 (6.8%) Asian Vs - 2 (66.7%) - 1(33.3%) 0.217; NS Mixed 9 (22.0%) 24 (58.5%) 6 (14.6%) 2 (4.9%) Caucasian Vs 6 (22.2%) 16 (59.3%) 4 (14.8%) 1 (3.7%) 0.042* Hispanic 3 52 (70.3%) 14 (18.9%) 5 (6.8%) Caucasian Vs 6 (22.2%) 16 (59.3%) 4 (14.8%) 1 (3.7%) 0.997; NS Mixed 9 24 (58.5%) 6 (14.6%) 2 (4.9%) Hispanic Vs 3 52 (70.3%) 14 (18.9%) 5 (6.8%) 0.028* Mixed 9 (22.0%) 24 (58.5%) 6 (14.6%) Chi-Square Test: NS: p > 0.05; Not significant; *p<0.05; Significant; **p<0.001; Highly significant Table 3: Pair wise comparison of EARR grade among different ethnicities Discussion EARR remains a complex and clinically relevant complication of orthodontic treatment. Because root resorption may result in root shortening and compromise tooth stability, it is crucial that clinicians understand both its prevalence and contributing risk factors. In the current cross-sectional study, we assessed the prevalence and distribution of EARR in orthodontic patients at the UNLV School of Dental Medicine (SDM). Our findings provide insight into demographic, ethnic, and age-related patterns of EARR in this patient population. In our sample, EARR prevalence was higher in females (60.8%) than in males (39.2%). This aligns with suggestions that hormonal influences and sex-related differences in bone metabolism may affect EARR risk. However, literature findings are mixed. Some studies reported no significant correlation between sex and EARR (Harris et al. 1997 ; Sameshima and Sinclair 2001 ), whereas others found greater root resorption among females (Levander et al. 1998 ; Kjaer 1995 ; Guo et al. 2016 ; Jiang et al. 2003 ). Conversely, some reports indicated males might be at higher risk (Guo et al. 2016 ). Our findings support studies reporting higher incidence in females (Levander and Malmgren 1988 ; Heboyan et al. 2018 ; Bayir and Gumus 2021 ). Genetic factors also heavily influence bone mass, with certain chromosomal loci strongly associated with bone mineral density (BMD) (Hou et al. 2020 ). Because alveolar bone integrity is pivotal during orthodontic loading, differences in BMD may modulate susceptibility to EARR. Ethnic variation in BMD, partly driven by genetic and metabolic differences such as vitamin D metabolism, has been documented in Hispanic populations and may partly explain our observation of increased EARR prevalence among Hispanic patients (Hou et al. 2020 ; Wu and Dai 2023 ; Durdin et al. 2022 ). In our study, Hispanic patients exhibited the highest rate of EARR (50%), followed by individuals of mixed ethnicity (27%), with Asian and African American patients showing the lowest rates. Statistically significant differences in EARR grades were found between African American and Hispanic, Caucasian and Hispanic, and Hispanic and Mixed groups. These results suggest that genetic predisposition, cultural oral health behaviors, and disparities in orthodontic care access may influence EARR susceptibility across ethnic groups. Recent narrative reviews have identified several candidate gene polymorphisms associated with EARR, highlighting the potential for future pre-treatment risk profiling (Kalra et al. 2020 ). Previous investigations also found greater susceptibility to resorption among Hispanic groups compared to Asians (Sameshima and Sinclair 2001 ), consistent with our findings of a significant association between EARR and Hispanic ethnicity. Most EARR cases in our sample were classified as Grade 2, representing moderate resorption, whereas only 6.1% were Grade 4 (severe). One-way ANOVA revealed significant differences in mean patient age across EARR grades. Patients with Grade 1 EARR had the highest mean age, which might reflect shorter treatment duration, less forceful treatments, or a reduced biological response. Conversely, Grades 3 and 4 were associated with younger patients, potentially reflecting greater biological susceptibility to resorption under orthodontic forces. The significant ethnic disparities and age-related trends observed underscore the importance of personalized orthodontic planning that accounts for risk factors such as ethnicity, age, and sex. Early diagnosis and close monitoring of root resorption are particularly critical in younger patients and those from higher-risk ethnic backgrounds, such as Hispanics. Genetic polymorphisms may, in the future, serve as predictive biomarkers to identify individuals at elevated risk of severe EARR (Liu et al. 2024 ). A limitation of our study was the use of periapical and panoramic radiographs. Panoramic imaging may underestimate root resorption compared to three-dimensional modalities such as cone-beam computed tomography (CBCT) (Ren et al. 2013 ). However, some researchers suggest that well-taken panoramic films can be as diagnostic as periapical series while providing a better cost-benefit ratio (Bayir and Gumus 2021 ; Apajalahti and Peltola 2007 ; Pandis et al. 2008 ). Future longitudinal studies with larger and more diverse populations are needed to explore the underlying biological and genetic mechanisms driving these disparities. Such research will aid clinicians in developing strategies to minimize the risk of EARR during orthodontic care. Conclusion Within the limitations of the present investigation, the presence of EARR was dominant among young adult female Hispanics. The grade of the EARR was level 2 which indicate the presence of moderate resorption, small area of root loss with the apex exhibiting an almost straight contour. Declarations Ethics Approval and Consent to Participate: As no additional radiographs or examinations were performed specifically for this study, and all collected data were analyzed and presented anonymously, the study was granted exempt status by the Institutional Review Board (IRB) of the University of Nevada, Las Vegas (#UNLV-1464468-3). Funding: No funding was received for the conduct of this study. Author Contribution MF, TA, NHA conceived the study and edited the manuscript; NHA wrote the manuscript; MF collected all the data; MF, TA, NHA contributed to interpreting results; TA, NHA contributed to methodology, validation, , project administration and revision of manuscripts. All Authors reviewed the manuscript. References Alqerban A, Jacobs R, Lambrechts P, Loozen G, Willems G. Root resorption of the maxillary lateral incisor caused by impacted canine: a literature review. Clin. Oral Investig. 2009;3:247–55. Levander E, Malmgren O. Evaluation of the risk of root resorption during orthodontic treatment: a study of upper incisors. Eur J Orthod. 1988;10:30–8. Weltman B, Vig KW, Fields HW, Shanker S, Kaizar EE. Root resorption associated with orthodontic tooth movement: a systematic review. Am J Orthod Dentofacial Orthop 2010;137:462–76. Segal GR, Schiffman PH, Tuncay OC. Meta analysis of the treatmentrelated factors of external apical root resorption. Orthod Craniofac Res. 2004;7:71–8. Shahrure B, Acar A. Evaluation of risk factors for severe apical root resorption in the maxillary incisors following fixed orthodontic treatment. Turk J Orthod. 2022;35(2):75. Nanekrungsan K, Patanaporn V, Janhom A, Korwanich N. External apical root resorption in maxillary incisors in orthodontic patients: associated factors and radiographic evaluation. Imaging Sci Dent 2012;42:147–54. Picanco GV, de Freitas KM, Cancado RH, Valarelli FP, Picanco PR, Feijao CP. Predisposing factors to severe external root resorption associated to orthodontic treatment. Dental Press J Orthod 2013;18:110–20. Roscoe, MG, Meira, JB, Cattaneo, PM. Association of orthodontic force system and root resorption: a systematic review. Am J Orthod Dentofacial Orthop. 2015;147:610–26. Dawood HM, Kroeger A, Chavda V, Chapple IL, Kebschull M. Under pressure—mechanisms and risk factors for orthodontically induced inflammatory root resorption: a systematic review. Eur J Orthod. 2023;45:612–26. Sharab LY, Morford LA, Dempsey J, Falcão-Alencar G, Mason A, Jacobson E, Kluemper GT, Macri JV, Hartsfield Jr JK. Genetic and treatment‐related risk factors associated with external apical root resorption (EARR) concurrent with orthodontia. Orthod Craniofac Res. 2015;18:71–82. Pinheiro LH, Guimaraes LS, Antunes LS, Küchler EC, Kirschneck C, Antunes LA. Genetic variation involved in the risk to external apical root resorption in orthodontic patients: a systematic review. Clin. 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Eur J Orthod. 1995;17:25–34. Guo Y, He S, Gu T, Liu Y, Chen S. Genetic and clinical risk factors of root resorption associated with orthodontic treatment. Am J Orthod Dentofac Orthop. 2016;150:283–9. Jiang RP, Zhang D, Fu MK. A factors study of root resorption after orthodontic treatment. Chin. J. Stomatol. 2003;38:455–7. Heboyan AG, Avetisyan AA, Margaryan MM. Clinical case of a rarely diagnosed tooth root internal resorption. New Armen. Med. J. 2018;12(4). Bayir F, Gumus EB. External apical root resorption after orthodontic treatment: Incidence, severity and risk factors. J. Dent. Res. Dent. Clin. Dent. Prospect. 2021;15:100. Hou R, Cole SA, Graff M, Haack K, Laston S, Comuzzie AG, Mehta NR, Ryan K, Cousminer DL, Zemel BS, Grant SF. Genetic variants affecting bone mineral density and bone mineral content at multiple skeletal sites in Hispanic children. Bone. 2020;132:115175. Wu Q, Dai J. Racial/Ethnic differences in bone Mineral density for osteoporosis. Curr Osteoporos Rep. 2023;2:670–84. Durdin R, Parsons C, Dennison EM, Williams S, Tillin T, Chaturvedi N, Cooper C, Harvey NC, Ward KA. Inflammatory status, body composition and ethnic differences in bone mineral density: The Southall and Brent Revisited Study. Bone. 2022;155:116286. Kalra S, Gupta P, Tripathi T, Rai P. External apical root resorption in orthodontic patients: molecular and genetic basis. J. Family Med. Prim. Care. 2020;9(8):3872–82. Ren H, Chen J, Deng F, Zheng L, Liu X, Dong Y. Comparison of cone-beam computed tomography and periapical radiography for detecting simulated apical root resorption. Angle Orthod. 2013;83:189–95. Apajalahti S, Peltola JS. Apical root resorption after orthodontic treatment -- a retrospective study. Eur J Orthod. 2007;29:408–12. Pandis N, Nasika M, Polychronopoulou A, Eliades T. External apical root resorption in patients treated with conventional and self-ligating brackets. Am J Orthod Dentofac Orthop. 2008;134:646–51. Liu J, Park K, Choi YJ, Lee JH, Cha JY. Genetic polymorphisms linked to extreme postorthodontic external apical root resorption in Koreans. Prog Orthod. 2024;25:23. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7744427","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":523265325,"identity":"47f193f8-5f35-45a1-98bf-1d107242cde1","order_by":0,"name":"Michael Francis","email":"","orcid":"","institution":"University of Nevada, Las Vegas","correspondingAuthor":false,"prefix":"","firstName":"Michael","middleName":"","lastName":"Francis","suffix":""},{"id":523265327,"identity":"17d2ca8f-5ae2-472f-931a-8c5cae2b0f8d","order_by":1,"name":"Tanya Al Talib","email":"","orcid":"","institution":"University of Nevada, Las Vegas","correspondingAuthor":false,"prefix":"","firstName":"Tanya","middleName":"Al","lastName":"Talib","suffix":""},{"id":523265329,"identity":"0e12bab2-91bf-4627-a999-01725cdca61d","order_by":2,"name":"Neamat Hassan Abubakr","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7ElEQVRIiWNgGAWjYBCDBAhVwcDAB6J5iNAA1XKGgYGNNC2MbURoMWdvfrrh5w+GPP7+4w8/F847nMcmkcD44G0bbi2WPcfMbvYkMBRL3Mgxlp657XAxUAuz4Vw8WgxuJJjd4ElgSGy4wcMgzbvtcGIbzwE2aV58Wu4//3bzD1DL/PPHH//mnQPWwv4br5YbPGa3QbZsOJBgJs3bANTC3sDGjFfLmZyy2zJpEokbb+SYWfMcSwdqaWyWnHMOj5bjx7fdfGNjkzgP6LDbPDXWif3MzAc/vCnDrQUKJJA5jA0E1Y+CUTAKRsEowA8A7PRTfQD1d2kAAAAASUVORK5CYII=","orcid":"","institution":"University of Nevada, Las Vegas","correspondingAuthor":true,"prefix":"","firstName":"Neamat","middleName":"Hassan","lastName":"Abubakr","suffix":""}],"badges":[],"createdAt":"2025-09-29 17:38:23","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7744427/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7744427/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":93881848,"identity":"54839e85-9714-4982-b5f1-804d99919999","added_by":"auto","created_at":"2025-10-19 16:51:22","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":30517,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDescriptive data collection flowchart\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7744427/v1/ef8c3d982c729ad78f96f7ba.jpg"},{"id":93881850,"identity":"394bba65-a125-4121-a015-59819109a406","added_by":"auto","created_at":"2025-10-19 16:51:23","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":22581,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eLevander \u0026amp; 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As more patients are treated with fixed orthodontic appliances, the associated risks\u0026mdash;such as caries, periodontal complications, and root resorption\u0026mdash;become increasingly relevant. One such complication is external apical root resorption (EARR), a condition arising from the pathological or physiological activity of resorptive cells, which leads to loss of the root apex and consequent shortening or deformation of the root (Alqerban et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eEARR is a multifactorial and complex phenomenon, exhibiting variable severity among different patients and even among different teeth within the same individual. It is considered an undesirable outcome of orthodontic tooth movement. Several studies have found that much of the root resorption occurs during the first 6\u0026ndash;9 months of treatment (Levander and Malmgren \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1988\u003c/span\u003e). In fixed-appliance orthodontics, EARR is often viewed as an iatrogenic consequence. Numerous risk factors have been implicated, including malocclusion type, patient age, root morphology, dental anomalies, duration of treatment, and prior trauma (Weltman et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Segal et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Shahrure and Acar \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Nanekrungsan et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Picanco et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eA positive association has been noted between higher orthodontic force levels and increased root resorption (Roscoe et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Dawood et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Orthodontic tooth movement itself has been estimated to account for one-tenth to one-third of the total variance in EARR (Roscoe et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Significant reduction in root length can adversely affect the dentition, particularly when accompanied by alveolar bone loss (Roscoe et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eGenetic predisposition also plays a critical role in EARR susceptibility. Twin and association studies suggest that genetic factors account for a portion of the observed variation in post-orthodontic root resorption (Sharab et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Pinheiro et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Baghaei et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Nieto-Nieto et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). A growing body of literature addresses the incidence, etiology, and management of EARR across diverse populations. The present study aims to evaluate the prevalence and characteristics of EARR among orthodontic patients treated at the UNLV School of Dental Medicine.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eIn the present cross-sectional study,\u0026nbsp;clinical notes from patients at the University of Nevada, Las Vegas (UNLV) dental clinics were analyzed using AxiUm™ software. A search was conducted using\u0026nbsp;the following keywords “orthodontics”, “root resorption”, and “external apical root resorption” to identify the number of orthodontic documented patients at SDM, UNLV. The inclusion criteria encompassed patients who had previous orthodontic treatment, non-extracted cases, no congenital abnormalities, no preexisting documented root resorption or endodontic treatment prior to the study. Figure 1, shows the demographics of the collected data.\u0026nbsp;The MiPACS (Medical Imaging Picture Archiving and Communication System) is a comprehensive digital imaging system fully integrated with the axiUm™ dental software, and it was used for all examined radiographic.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eFigure 1: Descriptive data collection flowchart\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMiPACS is the primary imaging module for capturing, viewing, and managing dental radiographs such as intraoral radiographs, cephalometric, and panoramic images. MiPACS enhances clinical diagnostics with advanced image enhancement tools, including zoom, contrast adjustment, annotations, and measurement tools.\u0026nbsp;The amount of EARR was evaluated using the Levander \u0026amp; Malmgren ranking of the EARR levels [figure 2]\u0026nbsp;(Levander and Malmgren 1988). The ranking was as follows:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eGrade 0:\u003c/em\u003e\u003c/strong\u003eAbsence of root resorption;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eGrade 1:\u003c/em\u003e\u003c/strong\u003eMild resorption, root with its normal length, and only an irregular contour;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eGrade 2:\u003c/em\u003e\u003c/strong\u003eModerate resorption, small area of root loss with the apex exhibiting an \u0026nbsp;almost straight contour;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eGrade 3:\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eAccentuated resorption, loss of almost one third of root length; and\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eGrade 4:\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eExtreme resorption, loss of more than one third of the root length\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 2: Levander \u0026amp; Malmgren EARR ranking levels [2]\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Chi-square tests and One-Way ANOVA were used to analyses the results. \u0026nbsp;The association between EAR grades and ethnicity cross tabulation was assessed using Pearson chi- squared test (SPSS version 28).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e148 patients of Orthodontic patients of the SDM UNLV presented with EARR. Among all EARR cases, females comprised 60.8%, with males accounting for 39.2% of total cases. Results showed that Hispanics had the most significant incidence of EARR (50%) followed by mixed ethnicity (27%) while both Asian and African American had the least EARR (Figure 3).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eFigure 3: EARR distribution according to ethnicity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmong all EARR cases, 59% occurred in individuals under the age of 18, followed by 22% in the 18\u0026ndash;24 age group, 14% in the 25\u0026ndash;34 age group, and 3% in the 35\u0026ndash;44 age group. Patients aged 45 years and older accounted for less than 3% of EARR cases. The majority of cases were classified as Grade 2 EARR, while only 6.1% were categorized as Grade 4 EARR (Table 1). Sample cases of different grades of EARR are show in figure 4.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAnalysis using one-way ANOVA demonstrated a significant difference in the mean age among cases with different EARR grades. Cases with Grade 1 EARR exhibited the highest mean age, followed by Grades 2, 4, and 3, respectively (Table 1).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 97px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eN (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean Age (Years)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026plusmn; SD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 97px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003e20 (13.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e25.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e13.983\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e0.019*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 97px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003e95 (64.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e19.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e8.896\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 97px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003e24 (16.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e17.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e4.709\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 97px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003e9 (6.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e17.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e4.096\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e*p \u0026lt; 0.05; Significant\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1: EARR ranking level distributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 4: Cases with different EARR grades.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Chi-Square test was employed to assess the distribution of various EARR grades across ethnicity, gender, and dental arch. The analysis revealed that the distribution of EARR grades differed significantly among ethnic groups. In contrast, no statistically significant differences were observed in the distribution of EARR grades concerning gender or dental arch (Table 2).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"624\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" rowspan=\"2\" valign=\"top\" style=\"width: 210px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eN (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003eN (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eN (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eN (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEthnicity\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eAfrican American\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e1 (33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e0.037*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eAsian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1 (33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eCaucasian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e6 (22.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e16 (59.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e4 (14.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1 (3.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eHispanic\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e3 (4.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e52 (70.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e14 (18.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e5 (6.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eMixed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e9 (22.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e24 (58.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e6 (14.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (4.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGender\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e13 (14.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e55 (61.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e17 (18.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e5 (5.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.659; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e7 (12.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e40 (69.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e7 (12.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e4 (6.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eArch\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e8 (19.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e23 (56.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e6 (14.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e4 (9.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.055; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e5 (23.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e16 (76.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eU/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e7 (8.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e56 (65.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e18 (20.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e5 (5.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eChi-Square Test: NS: p \u0026gt; 0.05; Not significant; *p\u0026lt;0.05; Significant\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2: Distribution of different EARR grades among ethnicity, gender and arch\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Pairwise comparisons of EARR grades among ethnic groups using the Chi-Square test indicated that statistically significant differences were present specifically between African American and Hispanic, Caucasian and Hispanic, and Hispanic and Mixed ethnicities (Table 3).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"654\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEthnicity\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 1\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eN (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 2\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eN (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 3\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eN (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 4\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eN (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAfrican American Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e1 (33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.189; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAsian\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1 (33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAfrican American Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e1 (33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.411; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCaucasian\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e6 (22.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e16 (59.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e4 (14.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1 (3.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAfrican American Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e1 (33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001**\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHispanic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e3 (4.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e52 (70.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e14 (18.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e5 (6.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAfrican American Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e1 (33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e0.371; NS\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMixed\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e9 (22.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e24 (58.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e6 (14.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (4.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAsian Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1 (33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e0.196; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCaucasian\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e6 (22.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e16 (59.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e4 (14.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1 (3.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAsian Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1(33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e0.347; NS\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHispanic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e52 (70.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e14 (18.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e5 (6.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAsian Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e2 (66.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1(33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e0.217; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMixed\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e9 (22.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e24 (58.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e6 (14.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (4.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCaucasian Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e6 (22.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e16 (59.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e4 (14.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1 (3.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.042*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHispanic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e52 (70.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e14 (18.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e5 (6.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCaucasian Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e6 (22.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e16 (59.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e4 (14.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e1 (3.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e0.997; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMixed\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e24 (58.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e6 (14.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2 (4.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHispanic Vs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e52 (70.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e14 (18.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e5 (6.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.028*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMixed\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e9 (22.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e24 (58.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e6 (14.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eChi-Square Test: NS: p \u0026gt; 0.05; Not significant; *p\u0026lt;0.05; Significant; **p\u0026lt;0.001; Highly significant\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3: Pair wise comparison of EARR grade among different ethnicities\u003c/strong\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eEARR remains a complex and clinically relevant complication of orthodontic treatment. Because root resorption may result in root shortening and compromise tooth stability, it is crucial that clinicians understand both its prevalence and contributing risk factors. In the current cross-sectional study, we assessed the prevalence and distribution of EARR in orthodontic patients at the UNLV School of Dental Medicine (SDM). Our findings provide insight into demographic, ethnic, and age-related patterns of EARR in this patient population.\u003c/p\u003e\u003cp\u003eIn our sample, EARR prevalence was higher in females (60.8%) than in males (39.2%). This aligns with suggestions that hormonal influences and sex-related differences in bone metabolism may affect EARR risk. However, literature findings are mixed. Some studies reported no significant correlation between sex and EARR (Harris et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Sameshima and Sinclair \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2001\u003c/span\u003e), whereas others found greater root resorption among females (Levander et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e1998\u003c/span\u003e; Kjaer \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Guo et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Jiang et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Conversely, some reports indicated males might be at higher risk (Guo et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Our findings support studies reporting higher incidence in females (Levander and Malmgren \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1988\u003c/span\u003e; Heboyan et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Bayir and Gumus \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eGenetic factors also heavily influence bone mass, with certain chromosomal loci strongly associated with bone mineral density (BMD) (Hou et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Because alveolar bone integrity is pivotal during orthodontic loading, differences in BMD may modulate susceptibility to EARR. Ethnic variation in BMD, partly driven by genetic and metabolic differences such as vitamin D metabolism, has been documented in Hispanic populations and may partly explain our observation of increased EARR prevalence among Hispanic patients (Hou et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Wu and Dai \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Durdin et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). In our study, Hispanic patients exhibited the highest rate of EARR (50%), followed by individuals of mixed ethnicity (27%), with Asian and African American patients showing the lowest rates. Statistically significant differences in EARR grades were found between African American and Hispanic, Caucasian and Hispanic, and Hispanic and Mixed groups. These results suggest that genetic predisposition, cultural oral health behaviors, and disparities in orthodontic care access may influence EARR susceptibility across ethnic groups.\u003c/p\u003e\u003cp\u003eRecent narrative reviews have identified several candidate gene polymorphisms associated with EARR, highlighting the potential for future pre-treatment risk profiling (Kalra et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Previous investigations also found greater susceptibility to resorption among Hispanic groups compared to Asians (Sameshima and Sinclair \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2001\u003c/span\u003e), consistent with our findings of a significant association between EARR and Hispanic ethnicity. Most EARR cases in our sample were classified as Grade 2, representing moderate resorption, whereas only 6.1% were Grade 4 (severe). One-way ANOVA revealed significant differences in mean patient age across EARR grades. Patients with Grade 1 EARR had the highest mean age, which might reflect shorter treatment duration, less forceful treatments, or a reduced biological response. Conversely, Grades 3 and 4 were associated with younger patients, potentially reflecting greater biological susceptibility to resorption under orthodontic forces.\u003c/p\u003e\u003cp\u003eThe significant ethnic disparities and age-related trends observed underscore the importance of personalized orthodontic planning that accounts for risk factors such as ethnicity, age, and sex. Early diagnosis and close monitoring of root resorption are particularly critical in younger patients and those from higher-risk ethnic backgrounds, such as Hispanics. Genetic polymorphisms may, in the future, serve as predictive biomarkers to identify individuals at elevated risk of severe EARR (Liu et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eA limitation of our study was the use of periapical and panoramic radiographs. Panoramic imaging may underestimate root resorption compared to three-dimensional modalities such as cone-beam computed tomography (CBCT) (Ren et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). However, some researchers suggest that well-taken panoramic films can be as diagnostic as periapical series while providing a better cost-benefit ratio (Bayir and Gumus \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Apajalahti and Peltola \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Pandis et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Future longitudinal studies with larger and more diverse populations are needed to explore the underlying biological and genetic mechanisms driving these disparities. Such research will aid clinicians in developing strategies to minimize the risk of EARR during orthodontic care.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWithin the limitations of the present investigation, the presence of EARR was dominant among young adult female Hispanics. The grade of the EARR was level 2 which indicate the presence of moderate resorption, small area of root loss with the apex exhibiting an almost straight contour.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eEthics Approval and Consent to Participate:\u003c/h2\u003e\u003cp\u003eAs no additional radiographs or examinations were performed specifically for this study, and all collected data were analyzed and presented anonymously, the study was granted exempt status by the Institutional Review Board (IRB) of the University of Nevada, Las Vegas (#UNLV-1464468-3).\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e\u003cp\u003eNo funding was received for the conduct of this study.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eMF, TA, NHA conceived the study and edited the manuscript; NHA wrote the manuscript; MF collected all the data; MF, TA, NHA contributed to interpreting results; TA, NHA contributed to methodology, validation, , project administration and revision of manuscripts. All Authors reviewed the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlqerban A, Jacobs R, Lambrechts P, Loozen G, Willems G. Root resorption of the maxillary lateral incisor caused by impacted canine: a literature review. Clin. Oral Investig. 2009;3:247\u0026ndash;55.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLevander E, Malmgren O. Evaluation of the risk of root resorption during orthodontic treatment: a study of upper incisors. Eur J Orthod. 1988;10:30\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWeltman B, Vig KW, Fields HW, Shanker S, Kaizar EE. Root resorption associated with orthodontic tooth movement: a systematic review. Am J Orthod Dentofacial Orthop 2010;137:462\u0026ndash;76.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSegal GR, Schiffman PH, Tuncay OC. Meta analysis of the treatmentrelated factors of external apical root resorption. Orthod Craniofac Res. 2004;7:71\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShahrure B, Acar A. Evaluation of risk factors for severe apical root resorption in the maxillary incisors following fixed orthodontic treatment. Turk J Orthod. 2022;35(2):75.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNanekrungsan K, Patanaporn V, Janhom A, Korwanich N. External apical root resorption in maxillary incisors in orthodontic patients: associated factors and radiographic evaluation. Imaging Sci Dent 2012;42:147\u0026ndash;54.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePicanco GV, de Freitas KM, Cancado RH, Valarelli FP, Picanco PR, Feijao CP. Predisposing factors to severe external root resorption associated to orthodontic treatment. Dental Press J Orthod 2013;18:110\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRoscoe, MG, Meira, JB, Cattaneo, PM. Association of orthodontic force system and root resorption: a systematic review. Am J Orthod Dentofacial Orthop. 2015;147:610\u0026ndash;26.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDawood HM, Kroeger A, Chavda V, Chapple IL, Kebschull M. Under pressure\u0026mdash;mechanisms and risk factors for orthodontically induced inflammatory root resorption: a systematic review. Eur J Orthod. 2023;45:612\u0026ndash;26.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSharab LY, Morford LA, Dempsey J, Falc\u0026atilde;o-Alencar G, Mason A, Jacobson E, Kluemper GT, Macri JV, Hartsfield Jr JK. Genetic and treatment‐related risk factors associated with external apical root resorption (EARR) concurrent with orthodontia. Orthod Craniofac Res. 2015;18:71\u0026ndash;82.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePinheiro LH, Guimaraes LS, Antunes LS, K\u0026uuml;chler EC, Kirschneck C, Antunes LA. 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Prog Orthod. 2024;25:23.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"External apical root resorption, EARR, Orthodontics, Prevalence","lastPublishedDoi":"10.21203/rs.3.rs-7744427/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7744427/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\u003eWith the increased demand for orthodontic treatments in adults, external apical root resorption (EARR) has always been an complication during orthodontic treatment. The present study aimed to investigate the presence of external apical root resorption (EARR) among orthodontics patients attending dental clinics at the School of Dental Medicine, University of Nevada, Las Vegas.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA retrospective keywords search of the clinical notes of UNLV School of Dental Medicine (SDM) patient charts in axiUm\u0026trade; was performed using the search terms \u0026ldquo;orthodontics\u0026rdquo;, \u0026ldquo;root resorption\u0026rdquo;, and \u0026ldquo;external apical root resorption\u0026rdquo; to identify the number of orthodontic cases that clinically presented with EARR using the Levander \u0026amp; Malmgren ranking of the EARR levels. The inclusion criteria encompassed patients with previous orthodontic treatment, non-extraction cases, no congenital abnormalities, and no preexisting documented root resorption or endodontic treatment prior to the study. The patient population's inclusion criteria encompassed records of individuals who were \u0026ge;\u0026thinsp;12 years.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e\u003cp\u003e148 patients presented with EARR, the Hispanic population had the most significant incidence of EARR (50%). Among all EARR cases, 59% were under the age of 18 yrs, followed by the age group 18\u0026ndash;24 years (22%). Females comprised 60.8%, with males accounting for 39.2% of total cases. Most cases had a grade 2 EARR (64.2%) ranking as moderate resorption, while only 6.1% had a grade 4 EARR (Extreme resorption).\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWithin the limitations of the present investigation, the presence of EARR was dominant among young adult Hispanic females. Upper and lower anterior teeth exhibited more EARR with level 2, indicating moderate resorption.\u003c/p\u003e","manuscriptTitle":"Prevalence of external apical root resorption among orthodontic patients: a Cross-sectional study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-19 16:51:18","doi":"10.21203/rs.3.rs-7744427/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"30a4817c-26a9-44e9-b01f-afd6abbcfb1b","owner":[],"postedDate":"October 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-10-28T18:14:34+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-19 16:51:18","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7744427","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7744427","identity":"rs-7744427","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}