Three-dimensional evaluation of angular, linear, and resorption features of maxillary impacted canines on cone-beam computed tomography

Long-term follow-up after the treatment of impacted canines in the maxilla causing severe root resorption of the lateral incisors: two case reports

BACKGROUND

Root resorption of adjacent teeth due to impacted canines is common, and orthodontic treatment often leads to secondary resorption or even loss of adjacent roots. Clinical reports of long-term stability after treatment are rare.

CASE PRESENTATION

This study reports two cases of maxillary impacted canines resulting in severe root resorption of the adjacent lateral incisors. Surgical exposure, orthodontic retraction, and alignment of the impacted canines were successful in both cases, and the resorbed lateral incisors were stable with no significant loosening and normal pulp vitality after treatment and at the 5- and 10-year follow-up appointments.

CONCLUSIONS

Light orthodontic force may be used to move adjacent teeth with root resorption due to tooth obstruction. The path and direction in which the teeth are moved must be specifically designed so that the adjacent roots are not resorbed and so long-term stability can be achieved.

Three-dimensional decision support system for treatment of canine impaction

INTRODUCTION

This study aimed to develop a 3-dimensional (3D) characterization of the severity of maxillary impacted canines and to test the clinical performance of this characterization as a treatment decision support tool.

METHODS

Cone-beam computed tomography images obtained from 83 patients with 120 impacted maxillary canines were included. Quantitative information on the canine 3D position and qualitative assessment of root damage of adjacent teeth were evaluated. A severity index was constructed on the basis of the quantitative findings. Clinical applicability was tested by comparing clinical diagnosis and treatment planning for conventional records vs the 3D characterization via a 2-part survey.

RESULTS

The average quantitative assessments of impacted maxillary canine position were 6.4 ± 3.6 mm from the midsagittal plane, 11.6 ± 3.1 mm in height relative to the occlusal plane, 31.5° ± 18° of roll, and 48.8° ± 14.3° of pitch. The severity index ranged from 0-13 with a mean score of 4.5 ± 2.2. Overlap with adjacent teeth was the greatest contributor (33%) to the index. Bicortically impacted canines caused the most severe root damage. Cone-beam computed tomography was preferred for assessing root damage and overall severity, whereas conventional imaging was sufficient for height and angulation assessment. The 3D report was very important or important for evaluating root damage, canine position, overall severity, and overlap. The 3D report changed most of the decisions relating to biomechanics, patient education, and treatment time estimate. The decision of exposure and traction vs extraction was changed 22% of the time after the presentation of the 3D report.

CONCLUSIONS

The overlap with adjacent teeth frequently contributes the most to the severity index. The 3D report provided relevant clinical information regarding the canine position, damage to adjacent teeth, and the severity index, with a profound impact on the decisions of the clinicians regarding biomechanics, patient education, and treatment time estimate.

Is There a Relationship Between Unilateral/Bilateral Impacted Maxillary Canines and Nasal Septum Deviation?

Introduction A deviated nasal septum may be associated with some dentofacial deformities. The aim of the study was to determine whether there is a relationship between some craniomaxillary features of unilateral and bilateral maxillary impacted canines and nasal septum deviation. Methods This is a retrospective study consisting of cone beam computed tomography (CBCT) images of 51 patients. All patients were divided into three subgroups: unilateral maxillary impacted canines (UMIC) (n=19) bilateral maxillary impacted canines (BMIC) (n=15), and control group (MC) (n=17). The septal deviation angle and some angular and dimensional measurements were performed. Differences in linear and angular measurements between the groups were analyzed using One-way ANOVA and the Kruskal-Wallis test. Pearson's correlation analysis was performed to determine the relationship between the septal deviation angle, septal deviation direction, nasal floor angle, and other parameters, and multivariate linear regression analysis was performed to determine the effect of variables in the septal deviation angle. Results Bilateral or unilateral position of the impacted canines was found to be effective on septal deviation. The septal deviation angle and the nasal floor angle values were found to be significantly higher in the UMIC and BMIC groups (p<0.001) than in the MC group. Maxillary width was found to be significantly lower in the BMIC group compared to the UMIC (p<0.01) and MC group (p<0.001). Septal deviation angle was positively correlated with septal deviation direction and nasal floor angle (p<0.001). Palatal width and nasal floor angle were found to be negatively correlated (p<0.05), and palatal depth and septal deviation direction were found to be positively correlated (p<0.01). Groups and septal deviation angle, septal deviation direction, and nasal floor angle were found to be negatively correlated (p<0.001). The multivariate linear regression analysis revealed an association between septal deviation angle, group (p<0.01), and nasal floor angle (p<0.05). Conclusion Bilateral or unilateral position of the impacted canines was found to be effective on septal deviation. The septal deviation angle values were found to be higher when the maxillary impacted canine was unilateral. Unilateral or bilateral positions of the impacted canine and the nasal floor angle were found to be factors affecting the formation of septal deviation.

Cone-beam computed tomographic reconstructions in the evaluation of maxillary impacted canines

Purpose

Prior to cone-beam computed tomography (CBCT), orthodontic competence included radiological interpretation. Nevertheless, maxillary impacted canines (MICs), because of their position and adjacent complex anatomy, have been challenging to interpret, particularly with regard to root resorption. Although CBCT cross-sectional reconstructions of MICs yielded clearer insights into its diagnosis and treatment planning, the value of simultaneously using 2 different cross-sectional or multiplanar reconstructions of the CBCT datasets - orthogonal and curved/panoramic multiplanar reconstructions - has hitherto not been considered.

Materials and Methods

Both orthogonal and curved/panoramic multiplanar reconstruction series of 5 screenshots were each reconstructed from the 5 cm × 5 cm CBCT datasets of 15 separate MICs. Fifteen credentialled and experienced orthodontist volunteers reviewed 2 separate PowerPoints of 15 randomized series each, 1 week apart. Their review considered 6 factors that could affect treatment: the position and level of the MIC, the presence or absence of root resorption, ankylosis, cysts, and dilaceration.

Results

All 15 orthodontists were statistically similar regarding overall years of experience and of CBCT use. Although either reconstruction alone allowed the orthodontists to determine whether ankylosis and, to a lesser extent, most of the other features were present or absent in the MIC, reviewing both reconstructions together was necessary to determine whether root resorption was present or absent in the adjacent tooth.

Conclusion

Reviewing both orthogonal and curved/panoramic multiplanar reconstructions was necessary to evaluate the presence or absence of root resorption in the teeth adjacent to MICs and that of many other features.

Investigation of the Relationship of Impacted Maxillary Canines with Orthodontic Malocclusion: A Retrospective Study

Impacted canines, which play an important role in smile aesthetics and functional occlusion, can lead to dental and skeletal malocclusions. In this study the aim was to evaluate the relationship between impacted maxillary canines and malocclusion. A total of 151 patients comprising 101 females and 50 males aged between 13 and 33 years were included. The groups were divided based on age, gender, skeletal and dental classification, and sector classification. Angular and linear measurements were performed on lateral cephalometric and panoramic radiographs. In panoramic radiographs, the vertical distance of the impacted canine to the occlusal plane and the angle between it and the bicondylar plane were measured and sector classification was performed according to its relationship with the root of the lateral incisor. Skeletal classification was performed according to the ANB angle on lateral cephalometric radiographs and dental classification by molar relationship via the intraoral photographs. The Chi-square test analyzed independent qualitative and quantitative data using Kruskal-Wallis and Man-Whitney U tests. The statistical significance level was accepted as p < 0.05. According to the intraclass correlation test, an excellent positive correlation was found with 0.985 for canine distance and 0.993 for canine angle between the repeated measurements. The impaction of the maxillary right canine was significantly highest in females and lowest in males. The impacted canine angle was significantly highest in sector 1 and lowest in sector 4. Distance to the occlusal plane was significantly higher in dental Class II and sector 4. It was observed that there was a considerable relationship between impacted maxillary canines and malocclusion; bilateral impacted canines were more frequent in skeletal Class III, and the distance of impacted canines to the occlusal plane increased while their angles decreased both in dental Class II and from sectors 1 to 4.

The findings of impacted and transmigrated maxillary and mandibular canines: a retrospective cone beam computed tomography study

BACKGROUND

The aim of this study was to examine and evaluate the maxillary and mandibular impacted and transmigrant canines, their relationship with neighboring tissues and pathology with cone beam computed tomography (CBCT).

METHODS

CBCT data of 217 patients, between January 2018 and December 2019, with a total of 293 impacted canines were retrospectively reviewed. Clinical records were also evaluated. Maxillary or mandibular localization, angulations, transmigration, lateral and premolar tooth resorption, apical dilacerations, pathological formations, presence of persistent deciduous canines and treatment methods were investigated.

RESULTS

For 293 impacted canines, 237 were in the maxilla and 56 in the mandible, with this difference being statistically significant (P<0.05). Among the 293 impacted canines, 14 (4.8%) transmigrated canines were detected. From the 14 transmigrant canines, 13 were in the mandible and 1 was in the maxilla. This difference was found statistically significant (P<0.05). Eighteen dentigerous cysts (10 maxilla, 8 mandible) and 4 odontomas (3 maxilla, 1 mandible) were found in impacted canines. For a total of 293 impacted canines, 57 were extracted, 13 were referred to orthodontics and a follow-up decision was made for 223 teeth.

CONCLUSIONS

Transmigration incidence is statistically significant, on a higher area of the lower jaw, compared to the upper jaw (P<0.05). In patients with impacted canines, taking CBCT together with a detailed clinical examination is effective in correct treatment planning and in minimizing complications that may occur during surgical extraction.

Unilateral vs Bilateral Maxillary Canine Impaction: A Cone-Beam Computed Tomography Study of Patterns and Associations

AIM

This retrospective study aimed to compare and evaluate the pattern of maxillary canine impaction and its association with other anomalies using cone-beam computed tomography (CBCT).

METHODS

A total of 59 CBCT records of patients (ages 12 and up) were divided into two groups: A total of 35 subjects with unilateral canine impactions and 24 subjects with bilateral canine impactions. The CBCT data were analyzed for the measurement of qualitative and quantitative variables.

RESULTS

In unilateral canine impaction, the mesiodistal (MD) width of the central incisors and the nasal cavity (NC) width were wider (p < 0.05). The canine-palatal plane (U3-PP) distance was significantly longer in bilateral canine impaction (p < 0.05). The distance of the impacted canines from the palatal and mid-sagittal planes, the anterior dental arch width, and the maxillary skeletal width changed significantly with the position of the impacted canines (p < 0.05). Males had 0.185 odds of presenting with a bilateral canine impaction as compared to females (p = 0.025). The odds of having bilateral canine impaction with a longer canine-midsagittal plane (U3-MSP) distance was 1.30 (p = 0.003).

CONCLUSION

The findings indicate a gender predilection with females showing a greater prevalence of bilateral canine impaction. Supernumerary teeth were associated with unilateral impacted canines and lower canine impaction with bilaterally impacted canines.

CLINICAL SIGNIFICANCE

Anomalies in the form of the maxillary central and lateral incisors, distance from the maxillary canine to the palatal plane and the mid-sagittal plane, NC width, maxillary skeletal width, and gender, are the best discriminating parameters between unilateral and bilateral canine impactions.

Cone beam computed tomography indications for interdisciplinary therapy planning of impacted canines

OBJECTIVE

To investigate how cone beam computed tomography (CBCT) affects the therapeutic planning of impacted maxillary canines.

STUDY DESIGN

A total of 132 impacted canines from 89 pediatric patients were collected from 3 specialist clinics in Stockholm, Sweden. An interdisciplinary therapy planning team consisting of 5 dental specialists evaluated each case and chose their preferred treatment alternative, initially without and later with CBCT images, to decide whether CBCT was justified for therapy planning. Predefined variables measurable using only 2-dimensional (2D) assessments were analyzed using stepwise logistic regression analyses.

RESULTS

The CBCT was considered indicated in 47% of the cases. Additional information from CBCT led to a treatment decision change in 9.8%. Significant 2D predictors for CBCT justification were horizontal canine angulation compared with vertical angulation (odds ratio [OR] = 10.9), extraction strategy involvement (OR = 6.7), and buccally positioned canines compared with palatal (OR = 5.3), central (OR = 25.0), and distal or uncertain positions (OR = 7.7).

CONCLUSIONS

The benefit-risk assessment of CBCT for impacted canines may be reinforced by performing and applying justification decisions for CBCT acquisition at the therapeutic thinking level. If preliminary treatment planning motivates further in-depth investigation of either root status or tooth location, a CBCT is indicated.

Root morphology of lateral incisors adjacent to impacted maxillary canines: A cone-beam computed tomography retrospective cross-sectional study

INTRODUCTION

To compare the root morphology of the maxillary lateral incisors (MLIs) adjacent to an impacted (IMC) versus non-impacted maxillary canine (non-IMC).

MATERIALS AND METHODS

This cross-sectional study included cone beam computed tomography (CBCT) images derived from 154 subjects (with unilateral/bilateral impacted maxillary canines or without canine impaction). Each MLI was considered as a unit of analysis. Thus, the study group included 122 MLIs adjacent to impacted maxillary canine (IMCG) and the control group included 122 MLIs adjacent to a non-impacted maxillary canine (CG). Groups were matched by age, sex and evaluation side. Root length, root dilaceration angle and root convergence angle were evaluated in both the coronal and sagittal planes. Comparisons between groups were made with Student's t-test and the chi-square test with Bonferroni correction (P<0.008, P<0.01, respectively).

RESULTS

The root measurements of the MLIs showed some significant differences between the groups. The coronal root length was 0.52mm shorter but not highly significant (P=0.032), the coronal root dilaceration angle was 7.51° smaller (P<0.001), and the coronal root convergence angle was 1.28° greater (P<0.001) in the IMCG compared to the CG. The orientation of root dilaceration in the MLIs showed significant differences between the groups: it was mostly distopalatal in the GC (87.5%), to a lesser extent in the IMCG (58.9%) and also mesiopalatal in the IMCG (22.3%), (P=0.001).

CONCLUSIONS

The root morphology of MLIs adjacent to an IMC showed a tendency of shorter length, smaller root dilaceration and greater root convergence in the coronal section than MLIs adjacent to a non-IMC.

Root Resorptions on Adjacent Teeth Associated with Impacted Maxillary Canines

Aim: Through the use of CBCT images, many unidentified features of impacted canines can be easily resolved. The potential collision of impacted maxillary canines and adjacent teeth could lead to root resorption (RR). The aim of this study is to examine the prevalence, location and severity of RR on adjacent teeth caused by impacted maxillary canines and the association between the adjacent teeth and the features of maxillary impacted canines on CBCT. Methods: This study examined 89 subjects with 108 maxillary impacted canines, having had no previous orthodontic treatment (mean age: 18.3 ± 4.1 years). The following impacted-canine-related parameters were analyzed on the CBCT images: location; RR levels on adjacent teeth; occlusal line and midline distances of impacted canines; and the angulations of impacted canines to the midline, lateral incisor and occlusal line. Logistic regression was used to evaluate the association between RR and the measured parameters on CBCT. Results: In this study, we found that the majority of our patients with impacted maxillary canines were female (62.5%). Of the total 108 maxillary impacted canines, 60.2% resorbed the adjacent teeth of the affected quadrants. Lateral incisors were the most affected (34.3%). The mean age of subjects with RR was 16.7 ± 3.5 years. The frequency of RR was statistically significantly higher in female subjects (40.4%). Slight RR was the most frequent (30.5%) and the highest incidence noted at the apical third of the root (29.6%). Regarding the impacted maxillary canine angulation to the midline and adjacent tooth, higher values of angulation caused severe forms of RR (p < 0.05). Conclusion: The sensitivity of CBCT allows for the accurate diagnosis of the location and the degree of RR, alongside the angulation and distance of impacted canines to adjacent teeth. The association between the linear and angular features of the impacted maxillary canines and RR was confirmed.

Skeletal and Dental Morphological Characteristics of the Maxillary in Patients with Impacted Canines Using Cone Beam Computed Tomography: A Retrospective Clinical Study

The aim of this study is to analyze the skeletal and dentoalveolar morphological characteristics of the maxillary in subjects with a unilateral palatally impacted canine using Cone Beam Computed Tomography (CBCT). A retrospective clinical study was conducted of 100 adult patients divided into two groups: one consisting of patients with a unilaterally palatally impacted maxillary canine (GI), with the subgroups in the right and left hemiarches (GI-R and GI-L), and the second, without impacted canine, as the control group (CG). The CBCT measured skeletal variables (maxillary basal width and alveolar crest height) and dentoalveolar variables (inclination of the upper incisor, tooth lengths of incisors and canines, arch length, tooth size and bone dental discrepancy). In skeletal variables, statistically significant differences were found in alveolar crest height (ACH) in all groups and subgroups (p < 0.01). In the dentoalveolar variables, there were differences in the angle of the upper incisor (II) and lateral incisor length (LLIL) between the GI and GC and the angle of the upper incisor (II′), arch length (AL′) and arch length-tooth size discrepancy (ATD′) among the GI subgroups (p < 0.01). There are skeletal and dentoalveolar differences in patients with unilateral palatally impacted maxillary canines, with lower angular and linear measurements compared with patients without impaction.

Orthodontic treatment in impacted maxillary canines. A review of the literature

The prevalence of impacted maxillary canines is 1 to 3%, with approximately 50% of impacted canines causing root resorption of adjacent teeth. If the permanent canine has not acquired its correct position, evaluation by an orthodontist is necessary to determine the most adequate treatment. Surgery and orthodontic treatment are used for the treatment of impacted canines in the maxilla affecting permanent dentition. Selection of the most adequate treatment to achieve the correct position of the canine tooth depends on the position of the canine. This article summarizes the different techniques available and describes their advantages, and cost-benefit considerations. The objective of this literature review is to describe the etiology of impacted maxillary canines and provide an update of the information on orthodontic treatments available for these patients.

Gray value measurement for the evaluation of local alveolar bone density around impacted maxillary canine teeth using cone beam computed tomography

Background

To investigate whether any relationship between local alveolar bone density and maxillary canine impaction using gray values from cone beam computed tomography.

Material and Methods

The cone beam computed tomography images of 151 patients were retrospectively evaluated. Maxillary canine was defined as an impacted tooth when root formation was complete and the patient’s age older than 13 or the other side of the maxillary canine has completely erupted. Similarly, complete eruption was defined as the tooth in its expected occlusion and position. Using the cone beam computed tomography software, the region of interest which was 5 mm2 in area, was placed in the trabecular bone on cross sectional cone beam computed tomography images and the gray value measurements were recorded. After measuring the gray values of all the teeth, the images were grouped according to the field of view size. Comparison of the gray values of impacted and non-impacted teeth was made between images with the same field of view size.

Results

A total of 151 patients, 101 (66.9%) female and 50 (33.1%) male, were included in the study. The mean age of the patients was 24.94 ±13.9. In images with a 40X40 field of view, the gray values of the impacted canine teeth were higher than the gray values of the non-impacted ones and statistically significant difference was found between them (p=0.003). However no statistically significant difference was found between the gray values of impacted and non-impacted canine teeth in 60x60 and 100x50 field of view (p=0.197, p=0.170, respectively).

Conclusions

We suggest using the smallest field of view size when evaluating bone density using gray values from cone beam computed tomography images and we support the idea that the local increased bone density may influence on impaction.

Key words:Cone-beam computed tomography, tooth, impacted, bone density, maxilla, image processing, computer-assisted.

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.

3D Evaluation of the Relationship between Different Vertical Growth Patterns and Cranial Base Angulations

Objectives This study aimed to compare cranial base angulations in subjects with high-angle, low-angle, and normal-angle vertical growth patterns using cone beam computed tomography (CBCT).

Design This study is a retrospective clinical research.

Settings This study was carried out at the Dentistry Faculty of Eskisehir Osmangazi University.

Participants According to skeletal vertical face growth patterns, 78 subjects (48 females and 30 males, average age: 13.19 ± 1.73 years) were divided equally into three groups: high angle, low angle, and normal angle groups.

Main Outcome Measures Cephalometric images were derived from CBCT, and patients were classified according to the SN-GoGn angle (sella-nasion, gonion gnathion angle). Sagittal, axial, and coronal cranial base angulations were measured in three-dimensional (3D) CBCT images. Data were analyzed using the Kolmogorov–Smirnov normality, Kruskal–Wallis, and Mann-Whitney U statistical tests.

Results There were statistically significant differences between the low-angle and high-angle groups according to sagittal cranial base angulation parameters (p = 0.01). Conversely, there were no statistically significant differences between vertical facial growth patterns according to coronal and axial cranial angle variables (p > 0.05).

Conclusion According to the study results, there were no effects of cranial base angulations in two planes (coronal and axial) on different vertical skeletal growth patterns. In the sagittal cranial base angulation parameter, the high-angle group showed greater angulation values than the low-angle group. CBCT may be helpful for evaluating, diagnosing, and predicting 3D cranial base differences.

The correlation between the three-dimensional radiolucency area around the crown of impacted maxillary canines and dentigerous cysts

This study aimed to reveal the correlation between the radiolucency area around the crown of impacted maxillary canines and dentigerous cysts using cone beam CT (CBCT). CBCT data were obtained from patients with impacted maxillary canines. Three points of five areas (tooth cusp area and buccal, lingual, mesial and distal areas of the crown) were randomly selected, and the distance between the point and the surrounding hard tissue was measured respectively. The mean values were recorded as the radiolucency area. These results were compared with the occurrence of dentigerous cysts during surgery. 58 patients with 76 impacted maxillary canines were included. 14 of the 76 impacted canines were accompanied by cysts (18.42%). With the increase in the thickness of the radiolucency area, the incidence of cysts was significantly increased (p < 0.05). No cysts were found in the compacted canines with 0-1 mm thickness of the radiolucency area. The highest incidence (71.43%) was observed in canines with 3-4 mm thickness of the radiolucency area. This study found that the thickness of the radiolucency area around the crown of the maxillary impacted canine was closely related to the occurrence of dentigerous cysts. CBCT can be used to estimate the occurrence possibility of dentigerous cyst and guide surgical operations.