Three-dimensional localization of impacted canines and root resorption assessment using cone beam computed tomography

Influence of alveolar bone thickness and bucco-palatal inclination on root resorption of lateral incisors in unilateral maxillary impacted canines: a retrospective observational study

BACKGROUND

This study aimed to investigate the potential associations between alveolar bone thickness, bucco-palatal inclination of maxillary lateral incisors, and lateral incisor root resorption in patients with unilateral maxillary impacted canines (UMICs).

METHODS

A total of three hundred and five subjects (120 males, 185 females; mean age, 16.39 years; standard deviation, 4.04) with UMICs were included. Canine position and root resorption were assessed using CBCT. UMICs were divided into palatal, buccal and mid-alveolus groups (PICs, BICs and MAICs), with 117, 137 and 51 subjects, respectively. Alveolar bone thickness and bucco-palatal inclination of lateral incisors were measured using the Dolphin software.

RESULTS

The prevalence of lateral incisor root resorption was significantly lower in the BICs (13.9%) than MAICs (29.4%) and PICs (29.1%). Alveolar bone thickness of the apical area was smaller in UMICs with lateral incisor root resorption than no resorption in both PICs (8.33 ± 1.64 vs 10.53 ± 2.55 mm) and BICs (8.94 ± 1.85 vs 10.76 ± 2.28 mm). Furthermore, lateral incisors on the impacted side were more buccally inclined in PICs with lateral incisor root resorption than no resorption, while in both BICs and MAICs, there was no statistical difference between lateral incisor root resorption than no resorption. Moreover, alveolar bone thickness of the apical area, rather than bucco-palatal inclination of lateral incisors, was significantly correlated with lateral incisor root resorption both in PICs and BICs.

CONCLUSIONS

Lateral incisor root resorption is less common in BICs. Thinner alveolar bone thickness at the apical area of lateral incisors can be considered as a potential risk factor for lateral incisor root resorption in UMICs.

Predictive factors associated with adjacent teeth root resorption of palatally impacted canines in Arabian population: a cone-beam computed tomography analysis

BACKGROUND

This study aimed to evaluate three-dimensionally the factors associated with adjacent teeth root resorption of palatally impacted canines.

METHODS

In this retrospective cross-sectional study, one-hundred and fourteen cone beam computed tomography scans with palatally impacted maxillary canines were evaluated for the presence of adjacent root resorption. Seven parameters were analyzed: alignment of maxillary incisors, presence of deciduous canines, first premolars' roots configuration, impacted canines rotation, angulation of impacted canine to the midline, contact relationship, and area of contact with adjacent teeth. The association between dependent and independent qualitative and quantitative variables was analyzed using chi-square and independent student's t-test, respectively. The multivariate analysis was performed using regression analysis. The significant value was set at P ≤ 0.05.

RESULTS

The overall incidence of vertical, horizontal impaction and adjacent root resorption were 92, 8 and 77.2%, respectively. The apical third was the most involved area (57%); resorption of a single tooth was found in 21.9% of the total sample. The most common resorbed teeth were lateral first premolars (24.6%), followed by central lateral incisors (20.2%), and lateral incisors (15.8%) of the total sample. The severity of resorption was highest in grade I (31.5%) and lowest in grade III (7.6%). Three variables showed significant differences between resorption and non-resorption groups namely; canine rotation (P < 0.013), contact relationship (P < 0.001), and area of contact with adjacent teeth (P < 0.001). Regression analysis revealed an association between adjacent root resorption and permanent canine rotation, adjacent premolars' roots configuration, contact relationship, and area of contact (P < 0.05).

CONCLUSION

Two-thirds of impacted maxillary canines showed a form of root resorption. The most commonly resorbed tooth was the lateral incisors while the least affected one was the central incisors with apical one-third being of the highest risk. The predisposing factors including the canine rotation, premolar with separated roots, contact relationship, and area of contact with adjacent teeth are to be considered for any interceptive treatment.

Root Resorption of Teeth Adjacent to Untreated Impacted Maxillary Canines: A CBCT Study

Objectives

The aim of this retrospective study was to determine the position of the impacted maxillary canine (IMC) and then to inspect the frequency, location, and extent of the consequent root resorption (RR) of the adjacent teeth by using CBCT.

Materials and Methods

Forty-one patients aged 12-68 who have 56 IMC detected on CBCT images were retrospectively examined in 3D. The canine position was determined by assessing the side of impaction, buccopalatal location, the distance of the canine cusp tip to the midline and to the occlusal plane, and canine angulation to the midline. RR of adjacent teeth was analyzed by investigating the nearest location of ectopic canine to adjacent teeth in horizontal and vertical dimensions in addition to measuring the degree of RR.

Results

Twenty-seven (48.2%) impacted canines were on the right side, and 29 (51.8%) were on the left. Most of these teeth 31 (55.4%) were located palatally, while buccal impaction was seen in only 13 (23.2%) canines and 12 (21.4%) were located centrally. The mean distance of the ectopic canine cusp tip to the occlusal plane was significantly higher in males (14.4 mm) than in females (10.7 mm). RR was seen in 9 central incisors (31.03%) and 21 lateral incisors (41.17%) as well as one case in the first and second premolar. This RR was slight for all the adjacent central incisors and premolars.

Conclusions

IMC is more frequent in females, palatally and apically. When left untreated, it may cause RR of some of the adjacent teeth with various degrees, however, with no gender preference.

Prevalence and risk factors of root resorption of adjacent teeth in maxillary canine impaction, among untreated children and adolescents

OBJECTIVES

The aim of this retrospective study was to assess in maxillary canine impaction cases both the prevalence of root resorption of adjacent teeth among untreated children and adolescents, and its associated risk factors.

SUBJECTS AND METHODS

Sixty subjects (mean age 12.2 years; SD 1.9; range 8-17 years) with 83 displaced maxillary canines and without any past or ongoing orthodontic treatment were included in this study. The presence of root resorption was evaluated on images from a single cone beam computed tomography (CBCT) unit. Potential risk factors were measured on the CBCT images and on panoramic reconstructions of the 3D data sets. The sample was characterized by descriptive statistics and multiple logistic regressions were performed to predict root resorption.

RESULTS

Root resorption of at least one adjacent tooth was detected in 67.5 per cent of the affected quadrants. It was found that 55.7 per cent of the lateral incisors, 8.4 per cent of the central incisors, and 19.5 per cent of first premolars were resorbed. Of the detected resorptions, 71.7 per cent were considered slight, 14.9 per cent moderate, and 13.4 per cent severe. Contact between the displaced canine(s) and the adjacent teeth roots was the only identified statistically significant risk factor, all teeth being considered (odds ratio [OR] = 18.7, 95% confidence interval: 2.26-756, P < 0.01). An enlarged canine dental follicle, a peg upper lateral, or an upper lateral agenesis were not significantly associated with root resorption of adjacent teeth, nor were age nor gender.

CONCLUSIONS

Root resorption of adjacent teeth was detected in more than two-thirds of a sample of sixty untreated children and adolescents.

To what extent are impacted canines associated with root resorption of the adjacent tooth?: A systematic review with meta-analysis

BACKGROUND

The authors' aim in this systematic review was to evaluate to what extent impacted canines are associated with root resorption (RR) of the adjacent tooth by using cone-beam computed tomography.

METHODS

The authors performed an open-ended electronic search of the Cochrane Library, Latin American and Caribbean Health Sciences Literature, PubMed (MEDLINE), Scopus, and Web of Science and a partial gray literature search by using Google Scholar, Open Grey, and ProQuest. The authors included studies in people (adolescents, adults, and older adult) with impacted maxillary permanent canines in which the investigators assessed the incidence of RR in adjacent teeth. The investigators detected RR by using cone-beam computed tomography. Two reviewers independently performed the study selection, data extraction, and risk of bias assessment with no language restrictions. The selection criteria included observational studies.

RESULTS

From the 953 studies recorded in databases, the authors included 18 studies. The meta-analysis results revealed that the most frequent position of impacted canines was 56.99% palatal (95% confidence interval [CI], 47.032% to 66.673%); the apical one-third was the most prevalent one-third for RR (56.87%; 95% CI, 38.880% to 73.628%). The intensity of RR was slight (43.2%; 95% CI, 35.229% to 51.352%), although 30.9% (95% CI, 19.007% to 44.261%) of RR was severe. Although the studies had different sample sizes, the main methodological problem was the absence of a control group and follow-up.

CONCLUSIONS

RR in maxillary incisors was correlated with their contact with maxillary canines during eruption. Delayed eruption or treatment of impacted canines may lead to resorption of the adjacent lateral and central incisors. All root levels and surfaces of teeth associated with impacted maxillary canines can be resorbed to different levels of severity, but the apical one-third with slight resorption is the most common.

PRACTICAL IMPLICATIONS

Knowing to what extent impacted canines are associated with root resorption of the adjacent tooth before starting any intervention, and being able to share this information with the patient, caregivers, or caregivers and patient, allows the choice of the most appropriate treatment.

A comparative study of cone beam computed tomography and conventional radiography in diagnosing the extent of root resorptions

Background

Root resorptions are assessed and diagnosed using different radiographical techniques. A comparison of the ability to assess resorptions on two-dimensional (2D) and three-dimensional (3D) radiographs is, hitherto, lacking. The aims of this study were to evaluate the accuracy of 2D (periapical radiographs, PA and panoramic radiograph, PAN) and 3D (cone beam computed tomography, CBCT) radiographic techniques in measuring slanted root resorptions compared to the true resorptions, a histological gold standard, in addition to a comparison of all the radiographic techniques to each other.

Methods

Radiographs (CBCT, PA, and PAN), in addition to histological sections, of extracted deciduous canines from thirty-four patients were analyzed. Linear measurements of the most and least resorbed side of the root, i.e., “slanted” resorptions, were measured using an analyzing software (Facad ®). For classification of slanted root resorptions, a modified Malmgren index was used.

Results

PAN underestimated the root length on both the least and most resorbed side. Small resorptions, i.e., low modified Malmgren scores, were more difficult to record and were only assessed accurately using CBCT. The root resorption scores were underestimated using PA and PAN. In assessment of linear measures, PAN differed significantly from both CBCT and PA.

Conclusions

CBCT is the most accurate technique when measuring and scoring slanted root resorptions.

Comparative analysis of impacted upper canines: Panoramic radiograph Vs Cone Beam Computed Tomography

Background

The use of CBCT exam in the study of IMC is not new. However, it’s still not known in what specific aspects CBCT exam shows a better result than then conventional exams. The aim of this study was to compare and conclude in what way the opinion regarding upper canine impaction differed when observing a panoramic image compared to the observation of a set of CBCT reconstructions.

Material and Methods

Twenty patients (10 males and 10 females) with a total of 28 impacted maxillary canines were identified from the database of the Department of Dentistry, Faculty of Medicine, University of Coimbra. For each canine, two different images were available: a panoramic image and a set of CBCT reconstructions. After a random distribution of both groups images, nine orthodontists completed a questionnaire where they were asked to evaluate ten different questions regarding canine impaction. Statistic analysis was performed using Cronbach’s alpha statistics, Kappa statistics and McNemar test, considering p<0,05 statistically significant.

Results

This study showed differences between the two images regarding tooth position. A statistical significant poor agreement was found between the two methods for the mesio-distal position of the apex (k=0,388, p<0,001) and for the labio-palatal tip cusp position (k=0,035, p=0,114). The adjacent root resorption showed a poor and very poor agreement between the two methods. Every other items were scored with an agreement between modalities ranging from moderate to strong.

Conclusions

The analyses of panoramic images versus CBCT images reconstructions provided different information regarding tooth position (especially concerning the mesio-distal apex position and the labio-palatal cusp position) but also in the assessment of root resorption. Further investigation should be done to determine in what cases CBCT exam has a clear advantage over conventional 2D exams, justifying its use.

Key words:Cone-Beam Computed Tomography, Orthodontics, Impacted Tooth, Root resorption.

Mandibular Canine Transmigration: Report of Three Cases and Literature Review

Aims and Objectives:

Transmigration is a rare phenomenon seen almost exclusively in the mandibular canines. The aim of the present study is to review transmigration phenomenon.

Materials and Methods:

Appropriate guidelines for a systematic review were followed. The time period selected for the present systematic review was 2001–2016. The studies were selected from various electronic databases on the basis of their title, study, design, keywords, and abstracts. A total of 150 citations were searched initially, and after proper screening, 59 relevant articles were included. Additional data was obtained by searching journals and reference lists.

Results:

The literature search shows that transmigration is more frequent in the mandible than maxilla. The etiology of the condition is obscure; however, multiple factors have been attributed to the condition. They are more readily recognized now with the advent of panoramic radiographs. Transmigration is a rare anomaly causing varied manifestations and requires an interdisciplinary approach for management.

Conclusion:

Early diagnosis of impacted canines is mandatory for timely treatment to ensure facial harmony and improved function.

Clinical Management of Impacted and Transmigrated Lower Canines

PURPOSE

Impacted, in particular transmigrated, lower canines are rare. If they transmigrate, then the most common treatment is extraction. Alternatively, the native tooth can be preserved; however, management is complex. This report describes a decision-making flowchart (DMFC) with surgical strategies for the management of impacted lower canines.

MATERIALS AND METHODS

Fifty-six patients had impacted lower canines, of which 16 were transmigrated. A preliminary version of the DMFC was used for the development of treatment plans to decide which strategy to apply to these complex cases. After removal of associated pathologies (for experimental tooth-preserving therapies), miniscrews were used as transient skeletal anchorage devices (TADs). The TADs allowed a closed surgical approach for impacted and transmigrated lower canine eruption. For autotransplantation, a dummy tooth was used for socket preparation to minimize the period of no blood supply to the graft.

RESULTS

After surgical exposure and TAD insertion, orthodontic treatment was performed in 4 patients. One patient was selected for successful autotransplantation. Nine patients had the transmigrated canines surgically removed. The remaining patients opted for "leave and observe." Based on the satisfactory long-term results with orthodontic treatment and autotransplantation and on published reports, the resulting DMFC presents key aspects of the treatment plan, namely 1) associated pathology, 2) patient age, 3) compliance, and 4) root tip position.

CONCLUSIONS

TAD-assisted orthodontic treatment and autotransplantation of impacted lower canines are tooth-preserving alternatives to extraction. The developed DMFC assists the complex treatment planning of impacted and transmigrated lower canines.

Combined orthodontic-surgical management of a transmigrated mandibular canine

The presence of an impacted mandibular canine is one of the most difficult challenges that an orthodontist will meet. Orthodontic treatment is planned on an individual basis after thoroughly considering the patient's overall facial and dentoskeletal characteristics; the duration, risks, and costs of treatment; patient preferences; and the orthodontist's experience. This article reports an orthodontic treatment of a boy, age 12.9 years, with an impacted mandibular canine in the permanent dentition that was successfully managed. Radiographic analysis indicated a transmigration of the mandibular right canine. The orthodontic treatment plan included extraction of the deciduous right canine followed by surgical exposure and ligation of the permanent canine. Eruption was properly guided, and the correct position of the tooth was achieved. This challenging treatment approach is described in detail, including the mechanics used to align the impacted canine.