Relationship between the impacted mandibular third molar and adjacent second molar' external root resorption by cone-bean computed tomography analysis.

BACKGROUND: The relationship between the impacted mandibular third molar (IMTM) and the external root resorption (ERR) of the mandibular second molar (MSM) was analysed with cone-beam computed tomography (CBCT). The risk factors affecting the ERR of the MSM were examined to provide a reference. MATERIAL AND METHODS: A total of 327 patients (total: 578 teeth) admitted to the Affiliated Hospital of Yanbian University for IMTM extraction from January 2017 to December 2019 was chosen and divided according to gender and age. The correlation between the IMTM and ERR of MSM was analysed, including inclination angle, impaction direction and depth. The relationship of mandibular ascending ramus classification with ERR of MSM was also analysed. In addition, the correlation between the MTM impaction type and the severity of ERR was analysed. RESULTS: The incidence of ERR of MSM in male patients was higher than in females (27.9% vs.17.6%, p = 0.018). The occurrence and the site of ERR showed statistical differences in the inclination angle [(≤20°, 3.6%) vs. (21°-40°, 27.1%) vs. (41°-60°, 27.6%) vs. (61°-80°, 25.6%) vs. (>80°, 31.7%), p <0.001], impaction direction [(Vertical, 1.1%) vs. (Mesial, 32.7%) vs. (Horizontal, 25.3%), p <0.001] and depth of MTM [(Low position, 38.6%) vs. (Median position, 32.0%) vs. (High position, 13.7%), p <0.001]. Also, there was a significant difference in the mandibular ascending ramus type [(Class I, 17.4%) vs. (Class II, 32.3%) vs. (Class III, 44.9%), p <0.001]. In addition, the severity of ERR showed statistical differences in the mesial (40.9%, p<0.05), lower impaction (54.5%, p<0.05) depth of MTM and type III of mandibular ascending ramus (63.6%, p<0.05). CONCLUSIONS: The inclination angle, impaction direction, and depth of MTM were the influencing factors for the occurrence and site of ERR. Also, mandibular ascending ramus type was the impact fact. For MTM with mesioangular, lower impaction, and mandibular ascending ramus with type III, the ERR of the MSM was severer.

The prevalence, characteristics, and risk factors of external cervical resorption: a retrospective practice-based study.

OBJECTIVES: External cervical root resorption (ECR) is a poorly understood and aggressive form of resorption. The purpose of this study was to examine the prevalence, characteristics, and risk factors associated with the occurrence of ECR in patients seeking endodontic care from private practice settings. MATERIALS AND METHODS: Records of 343 patients with 390 teeth diagnosed with ECR were identified from 3 private endodontic practices from 2008 to 2022. The patients' demographic information, systemic conditions, and dental history were recorded. The characteristics of the cases including Heithersay classification, pulpal and periapical status, and their management were documented. The association between case severity and potential predisposing factors was examined using chi-square analysis. RESULTS: The overall prevalence of ECR among patients seeking endodontic care was low (< 1%). However, there was a greater than twofold increase in the pooled prevalence from 2016 to 2021 (0.99%) compared to the data from 2010 to 2015 (0.46%). The most commonly affected teeth were anterior teeth (48.7%). Class II (30.0%) and class III (45.4%) defects were the most often identified. Patients with a history of trauma or orthodontic treatment were significantly more likely to be diagnosed with severe cervical resorption (class III or IV) (p < 0.05). CONCLUSIONS: There has been an increase in the prevalence of ECR in patients seeking endodontic care. A history of orthodontic treatment and traumatic dental mechanical injuries may predict the severity of resorption. CLINICAL RELEVANCE: The upward trend in the occurrence of ECR warrants close monitoring of the patients at high risk of developing the condition to facilitate early detection and management.

The effect of impacted third molars on second molar external root resorption, a cross-sectional cone beam computed tomography study.

BACKGROUND: Third molars have the highest prevalence of impaction in teeth and can cause pathological damage on the adjacent second molars. This study aims to evaluate the effects of factors related to impacted third molars on external root resorption (ERR) in adjacent second molars using cone-beam computed tomography (CBCT). MATERIAL AND METHODS: In CBCTs, the effect of impacted third molars on the root surface of adjacent second molars was investigated. Inclusion criteria for subjects were being older than 16 and younger than 55, presence of at least one impacted third molar and adjacent second molar. Exclusion criteria were pathology, a follicle gap greater than 5 mm, crowned second molar, severe decay, an artifact on a radiologic image, and previous surgery on the second or third molars. The investigations were made based on age range, gender, tooth inclination, Pell-Gregory classification, retention type, contact area, root formation, pericoronal width, and tooth absence on the same quadrant for potential risk factors. The collected data were statistically analyzed with R software. The Chi-Square test was used to find out any significant difference. Logistic regression analyses were done for potential risk factors for ERR. RESULTS: A total of 437 impacted third molars and adjacent second molars were investigated using CBCT. Of these, 381 met the inclusion criteria. Mesioangular and horizontal inclination, Pell-Gregory Class B-C, contact area, and retention type were found the statistically potential risk factors for ERR. CONCLUSIONS: The impacted third molar with horizontal or mesioangular position, and osseous retention, with Pell and Gregory Class B and C, are more likely to cause external root resorption in adjacent second molars.

Prevalence of second molar external root resorption caused by mandibular third molars: a CBCT study.

The aims of this study were to use cone beam computed tomographic (CBCT) scans to assess the prevalence of second molar external root resorption (ERR) caused by impacted mandibular third molars and to associate the location and severity of ERR with the third molar position using 2 classification systems-1 proposed by Pell and Gregory and the other proposed by Winter. In this cross-sectional study, 2 calibrated observers evaluated a total of 107 CBCT scans (71 female and 36 male patients). After the presence or absence of ERR was determined, ERR was classified according to its location (cervical, middle, apical third, or root apex) and severity (mild, moderate, or severe resorption). The data were assessed with the Pearson chi-square test, the chi-square test for linear trend, and Poisson regression analysis. The significance level was set at P < 0.05. The prevalence of second molar ERR in the sample as a whole was 47.7% (n = 51). The prevalence was significantly higher (69.4%) for male patients (P = 0.002; Pearson chi-square test). The probability that ERR would affect the second molar was 1.71 times greater when the third molar exhibited the Pell and Gregory class IC position (95% CI, 1.27-2.31) and 1.64 times greater when the third molar exhibited the Winter mesioangular position (95% CI, 1.38-1.95). There was a statistically significant association between ERR location and severity; the cervical third was the most affected by mild ERR and the middle third was the most affected by severe ERR. The prevalence of mandibular second molar ERR caused by impacted third molars is high, especially in male patients. Mandibular third molars in the Pell and Gregory class IC position or Winter mesioangular position demonstrated greater potential to result in ERR of the adjacent second molar.

Ectopic eruption of maxillary permanent first molars: Predictive factors for self-corrected and impacted outcome.

OBJECTIVE: The aim of this study was to describe the occurrence, angulation and mesialisation ratio of the ectopic eruption of the maxillary permanent first molar (PFM) and its correlation with the pathological resorption of maxillary primary second molar (PSM). METHODS: This retrospective study was performed using the subsequent panoramic radiographs of 11.924 child patients aged 6-10 years. Ectopic eruption status is categorised as self-corrected and impacted types. To evaluate the differences between the two groups (self-corrected and impacted), the angulation of PFM, mesialisation ratio of PFM, and degree of adjacent PSM root resorption were also assessed. The data were statistically analysed using ANOVA and chi-square tests. Pearson correlation was used to analyse whether a quantitative relationship exists between PFM mesialisation ratio and PSM root resorption. RESULTS: Ectopic eruption frequency was determined as 0.83%. The distribution of ectopic eruption according to gender shows a higher prevalence in males than females. In most cases of ectopic eruption, the eruption status was impacted. The impacted PFMs showed more negative vertical and positive horizontal angle between the PSM and PFM. There was no significant difference between eruption status and angles. Mesialisation ratio of impacted PFMs was significantly higher than self-corrected PFMs. There was significant difference between the PFM mesialisation ratio and the degree of PSM root resorption. CONCLUSION: Even if eruption disturbances do not occur frequently, making an early diagnosis is important to begin treatment at an optimal time. Although the relationship between horizontal and vertical angles and the ectopic eruption pattern is controversial, it is one of the clinical determinants. The mesialisation ratio of the impacted type was significantly higher than the self-corrected type. Self-correction of PFM was reduced in PSM with grade III and IV root resorption.

Frequency and association of maxillary ectopic canine with incisor root resorption and dental agenesis.

OBJECTIVE: To assess the frequency of maxillary ectopic canine both buccally and palatally displaced with incisor root resorption and dental agenesis. METHODS: The cross-sectional study was conducted from April 8 to June 29, 2019, at the Department of Orthodontics, Dr. Ishrat Ul Ebad Khan Institute of Oral Health Sciences, and Dow Dental College, Dow University Of Health Sciences, Karachi, and comprised orthodontic patients diagnosed with maxillary ectopic canine eruption. Root resorption and agenesis were diagnosed on panoramic films. Root resorption was further confirmed by periapical radiographs. Data was analysed using SPSS 21. RESULTS: Of the 98 subjects, 86(87.8%) had buccally displaced canines of which 38(44.2%) were associated with root resorption, while 12(12.2%) patients had palatally displaced canines of which 10(83.3%) had root resorption (p=0.011). Overall, 30(30.6%) lateral incisors were resorbed, 7(7.1%) both central and lateral incisors, 5(5.1%) premolars, and 6(6.1%) both lateral incisors and premolars were resorbed. Agenesis was detected in 10 (10.2%) subjects (p=0.62). CONCLUSIONS: There was found to be no association of maxillary ectopic canines with incisor root resorption and dental agenesis.

External root resorption in maxillary and mandibular second molars associated with impacted third molars: a cone-beam computed tomographic study.

OBJECTIVE: To separately investigate the prevalence and risk factors of external root resorption (ERR) in maxillary and mandibular second molars (M2s) adjacent to impacted third molars (M3s). MATERIALS AND METHODS: CBCT scans involving 184 maxillary and 323 mandibular impacted M3s were included. Age, gender, the impaction status of M3, the presence, severity, and location of ERR in M2 were assessed. Risk factors were identified by multivariate logistic regression analyses. RESULTS: The prevalence of ERR was 32.6% in maxillary and 52.9% in mandibular M2s (P < 0.001). Mesio-angulated and deeply impacted M3s were identified as risk factors for both ERR in maxillary and mandibular M2s (P < 0.05). Besides, age over 25 increased the risk of ERR in maxillary M2s (P < 0.05). ERR in maxillary M2s was overall more severe than that in mandibular M2s (P < 0.001). For maxillary M2s, ERR mostly occurred at the apical third, while the mandibular M2s ERR was most frequently detected at the cervical third. CONCLUSIONS: ERR occurring in M2s adjacent to impacted M3s is common, especially in mandibular M2s. ERR in maxillary M2s cannot be neglected because of its relatively high severity. Mesial angulation and impaction depth of M3 are significantly associated with ERR in M2s. For ERR in maxillary M2s, age is another predictive parameter. CLINICAL RELEVANCE: Considering the presence of ERR is associated with M3s' impaction, watchful monitoring or prophylactic removal of impacted M3s should be deliberated especially for the patients over 25 years and with mesially inclined and deeply positioned M3s.

A retrospective study: Do all impacted teeth cause pathology?

OBJECTIVE: The objective of this study is to determine the incidence of impacted teeth and the frequency of pathologies they caused by cone beam computed tomography (CBCT) retrospectively. MATERIALS AND METHODS: In this study, 608 patients' CBCT images were analyzed retrospectively. Detected impacted teeth were classified as incisor, canine, premolar, molar, third molar, and supernumerary teeth. The pathologies caused by impacted teeth are classified as cysts or tumors, tooth decay, root resorptions, and periodontal bone loss. RESULTS: Impacted teeth were detected in 34.37% of the 608 CBCT images included in the study. The distribution of impacted teeth was 9.4% incisor, 29.4% canine, 9.9% premolar, 2.9% molar, 9.3% supernumerary, and 39.9% third molar teeth. Approximately 63.7% of the impacted teeth caused a pathology. The pathology that was most commonly caused by impacted teeth was periodontal bone loss (44.4%), and respectively others were root resorptions (33.3%), cysts or tumors (8.6%), and tooth decay (2.3%). The most common cause of this pathology was right mandibular third molar teeth. CONCLUSION: Impacted teeth were common and they often caused a pathology. CBCT is a useful device to assess the impacted teeth. When the impacted teeth are evaluated, each tooth should be assessed within itself. If the impacted teeth are not caused by pathology, they can be kept under control.

Association of sickle cell haemoglobinopathies with dental and jaw bone abnormalities.

OBJECTIVE: To estimate the association between sickle cell anaemia and trait with dental and jaw bone abnormalities. SUBJECTS AND METHODS: Subjects (n = 369) were allocated to three groups: sickle cell anaemia, trait and control. Dental shape, number, size and position and changes in pulp chamber, root and periapex were analysed by intra-oral periapical radiographs. Integrity of lamina dura, quality of cancellous bone and bone trabeculation were also evaluated. Prevalence ratios (PR) were calculated (α = 0.05). RESULTS: Sickle cell anaemia had higher prevalence (PR:8.31) and number of teeth (PR:13.40) with external resorption; higher number of teeth with pulp calcification; partial and total loss of lamina dura; and higher prevalence of changes in trabecular structure of maxilla (PR:6.45) and mandible (PR:5.34). Sickle cell trait showed higher prevalence (PR:1.26) and higher number of teeth (PR:1.98) with partial loss of lamina dura; higher number of teeth with hypercementosis, changes in shape, size, periapex, total loss of lamina dura; and higher prevalence of changes in mandibular trabecular bone (PR:1.43). CONCLUSION: Pulp calcification and external resorption of the root were the most frequent dental alterations in sickle cell anaemia group, while in trait was higher frequency of changes in shape, size, periapex and root. Jaw bone changes were most prevalent in both homozygous and heterozygous subjects.

Apical root resorption during orthodontic treatment with clear aligners: A retrospective study using cone-beam computed tomography.

INTRODUCTION: We aimed to investigate the incidence and severity of orthodontically induced inflammatory root resorption (OIIRR) on maxillary incisors with clear aligner therapy using cone-beam computed tomography and to identify possible risk factors. METHODS: The root lengths of maxillary incisors were measured on orthogonal images from pretreatment and posttreatment cone-beam computed tomography examinations of 160 patients who received comprehensive orthodontic treatment with clear aligners. RESULTS: Mean absolute reductions in root length varied between 0.47 ± 0.61 mm and 0.55 ± 0.70 mm and were not significantly different between maxillary central and lateral incisors. The prevalence of severe OIIRR, defined as both maxillary central incisors experiencing greater than a 25% reduction in root length, was found to be 1.25%. Potential risk factors included sex, malocclusion, crowding, and posttreatment approximation of apices to the cortical plates. Race, interproximal reduction, previous trauma to the teeth, elastics, age, treatment duration, and pretreatment approximation of apices to the cortical plates did not significantly affect the amount of OIIRR. CONCLUSIONS: Comprehensive treatment with clear aligners resulted in minimal root resorption. Sex, malocclusion, crowding, and posttreatment approximation to the cortical plates significantly affected the percentage of change in root length. Posttreatment approximation of root apices to the palatal cortical plate showed the strongest association for increased OIIRR.

External root resorption of the second molar associated with mesially and horizontally impacted mandibular third molar: evidence from cone beam computed tomography.

OBJECTIVES: The aim of the present study was to assess the incidence and risk factors of ERR in second molars with mesially and horizontally impacted mandibular third molars using cone beam computed tomography (CBCT) images from patients in a Chinese tertiary referral hospital. MATERIALS AND METHODS: A total number of 216 patients with 362 mesially and horizontally impacted mandibular third molars who were treated at our institution from 2014 to 2015 was retrospectively included. The ERR in second molars was identified on CBCT multiplanar images. The associations between incidence of ERR and multiple clinical parameters were statistically analyzed by Chi-square test. Moreover, the risk factors for ERR in second molars were further assessed by multivariate regression analysis. RESULTS: The overall incidence of ERR in second molars was 20.17 % (73/362) as detected on CBCT images. The presence of ERR significantly associated with patients age and impaction depth of mandibular third molars. However, no significant relationship was found between ERR severity and impaction depth or ERR location. Multivariate regression analyses further revealed age over 35 years and impaction depth as important risk factors affecting the ERR incidence caused by mesial and horizontal impaction of mandibular third molar. CONCLUSIONS: ERR in second molar resulted from mesially and horizontally impacted mandibular third molar is not very rare and can be reliably identified via CBCT scan. CLINICAL RELEVANCE: Given the possibility of ERR associated with third molar impaction, the prophylactic removal of these impacted teeth could be considered especially for those patients with over 35 years and mesially and horizontally impacted teeth.

Bone Density and Dental External Apical Root Resorption.

When orthodontic patients desire shorter treatment times with aesthetic results and long-term stability, it is important for the orthodontist to understand the potential limitations and problems that may arise during standard and/or technology-assisted accelerated treatment. Bone density plays an important role in facilitating orthodontic tooth movement (OTM), such that reductions in bone density can significantly increase movement velocity. Lifestyle, genetic background, environmental factors, and disease status all can influence a patients' overall health and bone density. In some individuals, these factors may create specific conditions that influence systemic-wide bone metabolism. Both genetic variation and the onset of a bone-related disease can influence systemic bone density and local bone density, such as observed in the mandible and maxilla. These types of localized density changes can affect the rate of OTM and may also influence the risk of unwanted outcomes, i.e., the occurrence of dental external apical root resorption (EARR).

Primary molar infraocclusion: frequency, magnitude, root resorption and premolar agenesis in a Spanish sample.

AIM: This study was conducted to determine frequency, distribution and magnitude of infraocclusion in primary mandibular molars; to evaluate root resorption, the frequency of premolars agenesis and the association between primary molar infraocclusion and premolar agenesis. MATERIALS AND METHODS: The sample consisted of 472 children who were subdivided in 3 age groups. The magnitude of infraocclusion was determined following the Bjerklin and Bennett method modified by the authors. Radicular resorption was determined using the rating scale proposed by Bjerklin and Bennett evaluating mesial and distal roots separately. The development degree of corresponding premolars was determined using the Demirjian method. RESULTS: One hundred and three (21.8%) children presented infraocclusion. The first primary molar presented infraocclusion in a significantly higher frequency. Considering the 3 scores of infraocclusion, 61.1% of the affected molars were classified as mild infraocclusion. No differences were found considering the root resorption pattern for primary molars, infraoccluded or not. Significant differences were found in the presence of agenesis in the group of infraoccluded molars. CONCLUSION: The present study identified a high percentage of infraocclusion, demonstrating that the type of molar is an influent variable, that the first primary molar is the most affected one, especially mandibular molars, and that the majority was mainly of a mild degree. There were no significant differences between the exfoliation of infraoccluded and non infraoccluded primary molars. However, radicular resorption of infraoccluded molars presented a clear delay or was totally absent in infraoccluded molars associated with premolar agenesis. Significant differences in the presence of agenesis beneath infraoccluded molars were observed.

Prevalence and Characterization of External Cervical Resorption Using Cone Beam Computed Tomography.

INTRODUCTION: The aim of this study was to assess the prevalence of external cervical resorption (ECR) and characterize the cases of ECR using cone beam computed tomography (CBCT). METHODS: High-resolution CBCT scans of 6216 patients (2280 males and 3936 females), consecutively acquired during the period July 2021 to March 2022, were analyzed. Identified cases of ECR were characterized by 3 evaluators regarding lesion height, circumferential spread, portal of entry proximity to root canal, stage, location, and width. RESULTS: In a total of 38 patients and 40 teeth, ECR cases demonstrated an incidence of 0.61%. The median age of the patients was 39 years. Prevalence of ERC was 0.78% among males and 0.50% among females. The most affected teeth were the maxillary incisors and canines. The most frequent characteristics of the lesion were: extension up to the cervical third (47.5%), more than 270° circumferential spread (42.55%), probable pulpal involvement (57.5%), progressive stage (65%), supracrestal (52.1%) and mesial (34.7%) localization of >1 mm in size (52.1%) portals of entry. Cases with greater longitudinal involvement also showed greater circumferential progression (P = .008). There was no association between portal of entry location and bone crest or ECR reparative phase (P = .42). Inter-rater agreement ranged from good to very good. No association between portal of entry and ECR progression was observed. CONCLUSIONS: ECR showed low prevalence in the Brazilian population, affecting mostly anterior maxillary teeth of patients within a wide age range. CBCT allowed characterization of ECR lesions with good interobserver agreement.

Prevalence and characteristics of and risk factors for impacted teeth with ankylosis and replacement resorption - a retrospective, 3D-radiographic assessment.

BACKGROUND: Large variation in the prevalence of ankylosis and replacement resorption (ARR) is reported in the literature and most studies have relatively small patient numbers. The present retrospective study aimed to provide an overview on prevalence, location of, and associated risk factors with ARR based on a large sample of computed tomography (CT) / cone beam computed tomography (CBCT) scans of impacted teeth. The results should allow clinicians to better estimate the risk of ARR at impacted teeth. METHODS: The CT/CBCT scans of 5764 patients of a single center in Central Europe were screened with predefined eligibility criteria. The following parameters were recorded for the finally included population: gender, age, tooth type/position, number of impacted teeth per patient, and presence/absence of ARR. For teeth with ARR the tooth location in reference to the dental arch, tooth angulation, and part of the tooth affected by ARR were additionally registered. RESULTS: Altogether, 4142 patients with 7170 impacted teeth were included. ARR was diagnosed at 187 impacted teeth (2.6%) of 157 patients (3.7%); 58% of these patients were female and the number of teeth with ARR per patient ranged from 1 to 10. Depending on the tooth type the prevalence ranged from 0 (upper first premolars, lower central and lateral incisors) to 41.2% (upper first molars). ARR was detected at the crown (57.2%), root (32.1%), or at both (10.7%). After correcting for confounders, the odds for ARR significantly increased with higher age; further, incisors and first/second molars had the highest odds for ARR, while wisdom teeth had the lowest. More specifically, for 20-year-old patients the risk for ARR at impacted incisors and first/second molars ranged from 7.7 to 10.8%, but it approximately tripled to 27.3-35.5% for 40-year-old patients. In addition, female patients had significantly less often ARR at the root, while with increasing age the root was significantly more often affected by ARR than the crown. CONCLUSION: ARR at impacted teeth is indeed a rare event, i.e., only 2.6% of 7170 impacted teeth were ankylosed with signs of replacement resorption. On the patient level, higher age significantly increased the odds for ARR and on the tooth level, incisors and first/second molars had the highest odds for ARR, while wisdom teeth had the lowest.

The prevalence of root resorption of maxillary incisors caused by impacted maxillary canines.

OBJECTIVES: The aim of this study was to evaluate the prevalence of root resorption of maxillary incisors caused by impacted maxillary canines using low-dose dental computed tomography and to gain additional knowledge of the underlying aetiology and the progression of root resorption. MATERIALS AND METHODS: A total of 440 patients (mean age, 24.7 years) with 557 impacted maxillary canines were examined regarding their location and the occurrence of root resorption of maxillary incisors. RESULTS: The frequency of root resorption was 2 % of central and 7.7 % of lateral maxillary incisors. The location of the 557 impacted canines within the dental arch was palatal in 67.5 %, buccal in 15.4 % and central in 17.1 %. No significant differences could be shown with respect to the width and the shape of the dental follicle of the impacted maxillary canines and the presence of root resorption of incisors. The presence of root resorption of central (p < 0.0001) and lateral (p < 0.023) maxillary incisors was significantly correlated with an existing contact relationship of the impacted maxillary canines. CONCLUSIONS: Our investigation confirms the theory of prior reports comprising a much larger patient population, hypothesising that the dental follicle of impacted maxillary canines does not cause resorption of adjacent maxillary incisors per se. CLINICAL RELEVANCE: Root resorption of maxillary incisors is correlated with effects of contact of the impacted maxillary canines, and these findings should be considered in treatment planning. Our findings are consistent with other reports and may develop new treatment approaches for the treatment of this sequela.

Radiographic comparison of the extent of orthodontically induced external apical root resorption in vital and root-filled teeth: a systematic review.

OBJECTIVE: to critically analyse the available scientific literature radiographically comparing the incidence of orthodontically induced external apical root resorption (OIEARR) in human root-filled and vital teeth. METHODS: Several electronic databases (MEDLINE, PubMed, EMBASE, Scopus, Web of Science, CINAHL, and the Cochrane Database of Systematic Reviews and Google Scholar) were searched without limits, with the assistance of a senior librarian specialized in Health Sciences database searches. Human, in vivo studies that radiographically compared root resorption following fixed orthodontic treatment in root-filled and vital teeth were selected for full article review. Additionally, the bibliographies of the finally selected articles were hand searched to identify any relevant publications that were not identified by electronic searches. The lowest levels of evidence accepted for inclusion were case controls or cohort studies. Two authors independently reviewed and extracted data from selected studies. RESULTS: A total of 165 original articles were identified from electronic database searches and 2 from hand searches. Once selection criteria were applied, only four articles met all inclusion criteria, and individual analysis of the selected articles was undertaken. CONCLUSIONS: Based on available evidence, root-filled teeth do not appear to be more susceptible to OIEARR than their analogous vital teeth.

Open bite as a risk factor for orthodontic root resorption.

The purpose of the present study was to clarify the prevalence and degree of root resorption induced by orthodontic treatment in patients with and without open bite. One hundred and eleven patients treated with multibracket appliances were retrospectively selected from the patients and divided into non-open bite (NOB) and open bite (OB) groups. The severity of root resorption and the root shape were classified into five groups on periapical radiographs before and after treatment. Moreover, only in the OB group, all teeth were sub-divided into functional and hypofunctional ones that are occluding and non-occluding. As the results of multiple linear regression analysis of patient characteristics and clinical variables with the number of overall root resorption, the independent variables that were found to contribute significantly to root resorption were bite and abnormal root shape. The prevalences of root resorption evaluated in the number of patients were significantly higher in OB group than in NOB group, and those in the number of teeth were significantly higher in OB group than in NOB group, in particular anterior and premolar teeth. The prevalence of resorbed teeth with abnormal root shapes was also significantly higher in OB group than in NOB group. On the other hand, in OB group, the prevalences of root resorption and teeth with abnormal root shape were significantly greater in hypofunctional teeth than in normal functional teeth. There are more teeth with root resorption and abnormal root shape in open bite cases than in normal bite cases, and more teeth with abnormal root shapes and root resorption in hypofunctional teeth than in functional teeth.

Prevalence and Characteristics of Root Resorption Identified in Cone-Beam Computed Tomography Scans.

INTRODUCTION: Root resorption is a destructive process that compromises tooth structure and can result in tooth loss. Often it remains asymptomatic and is an incidental finding on radiographic examinations. The purpose of this study was to determine prevalence and characteristics of root resorption in patients referred for cone-beam computed tomography (CBCT) imaging for a variety of indications. METHODS: The study included CBCT scans of 1086 consecutive patients referred for CBCT imaging over an 18-month period. A total of 1148 scans were acquired. Data were abstracted from radiology reports, and prevalence estimates of resorption were computed for the aggregate sample and also across specific indications. RESULTS: Resorption was identified in 171 patients (15.7%, 95% CI: 13.6%-17.9%) and in 249 teeth with a prevalence range of 2.6%-92.3% across specific indications. An 18.7% of the patients had 2 resorption sites whereas 8.8% had 3 or more resorption sites. The majority of affected teeth were anteriors (43.8%), followed by molars (40.6%) and premolars (14.5%). The most prevalent resorption types were external (29.3%), cervical (22.5%), infection-induced apical resorption (13.7%), internal (9.6%), and impacted tooth induced (8.8%). The majority of teeth with resorption did not have prior endodontic treatment (73.9%) and had radiographically normal periapex (69.5%). Of 249 teeth with resorption, 31% presented as incidental finding. The prevalence of incidental findings of resorption increased with age, P < .05, and was significantly lower for anterior teeth (20.2%) as compared to premolars (41.7%) and molars (36.6%), (P < .05). CONCLUSION: The high proportion of incidental findings of resorption detected by CBCT suggests that resorption is not recognized/detected by conventional radiography and therefore remains underdiagnosed.