Local factors relating to mandibular canine impaction: A retrospective study

INTRODUCTION

This study aimed to investigate the characteristics of impacted and transmigrated mandibular canines and the association existing between them and some local factors, such as degrees of axial inclination of mandibular incisors, skeletal Class, and mandibular symphysis width.

METHODS

A retrospective observational study was performed on the medical records and radiographic examination (panoramic radiographs and lateral cephalograms) of 102 orthodontic patients divided into a study group, with at least 1 impacted mandibular canine (51 subjects) and a control group, without mandibular impaction (51 subjects). A chi-square test, t test, and analysis of variance test analysis were used to analyze the data.

RESULTS

Unilateral and buccal impaction and the presence of the deciduous canine were the more prevalent characteristics of impacted canines, whereas 39.2% presented transmigration. Furthermore, the persistence of the deciduous canine on the impaction side (P <0.0001) and the mesial axial inclination of the impacted canine (P <0.0001) were found to be statistically significant characteristics. A statistically significant association was found between the impaction of the mandibular canine and mandibular incisor to the mandibular plane angle (IMPA) (IMPA, 95.8°; P = 0.009). An additional statistically significant association was found with transmigrated canines (IMPA, 96.8°; P = 0.024).

CONCLUSIONS

The mesialization of the canine cusp and the persistence of the mandibular deciduous canine are characteristics frequently found in the impaction of the mandibular canine. An accentuated vestibular inclination of the mandibular incisors is significantly associated with mandibular canine impaction.

Screening for the risk of canine impaction, what are the presumptive signs and how does it affect orthodontics? A cross-sectional study in France

PURPOSE

The treatment of impacted canines is a challenge for orthodontists. The availability of suggestive clinical signs has become crucial for treatment before the potential for evolution ceases. The main objective was to evaluate the prevalence of the suspected displaced canine (SDC) and to highlight factors easily identifiable from the oral examination.

METHODS

SDC was assessed on panoramic X-rays, on the basis of the angle with the median sagittal plane and the degree of overlap with the permanent lateral incisor. Its association with mesio-distal tooth and palate widths was assessed by univariate analysis. Next, the association of SDC with temporary tooth extraction, expansion and/or premolar extraction was considered using the same modality.

RESULTS

In this retrospective study, the records of 292 patients aged 7 to 13 years were reviewed. SDC was detected in 39% of patients i.e., 28,8% of observed canines. Reduced coronal mesio-distal diameters of permanent maxillary central incisors, 8.7 ± 0.6 mm versus 8.8 ± 0.7 mm (p < .05), and first permanent molars, 10.0 ± 0.7 mm versus 10.2 ± 0.7 mm (p < .001), as well as reduced inter-molar width, 38.7 ± 2.7 mm versus 39.4 ± 2.9 mm (p < .01), were predictive factors. SDC led orthodontists to indicate extraction of maxillary primary canines, OR = 3,32 (p < .001) or even extraction of premolars, OR = 1,66 (p < .05).

CONCLUSION

This study confirmed the interest of panoramic X-rays in detected canines at risk of SDC. Dental factors can be combined to make screening more reliable and predict impaction that makes orthodontics complex.

TRIAL REGISTRATION NUMBER

Opinion n°21.131, dated 09.21.2021, retrospectively registered.

Prevalence of Ectopic Canine in Different Sagittal and Vertical Skeletal Patterns

AIM

The present investigation aims to find out the prevalence of ectopic canines among skeletal class I, II, and III malocclusions and to evaluate its variability among different genders and their growth patterns.

MATERIAL AND METHODS

The study sample included orthopantomograms (OPGs), lateral skull views, and study models of 999 patients collected from departmental archives. Among the selected samples, 258 were males and 738 were females. They were divided into skeletal class I, II, and III malocclusions sagittally and hypodivergent, normodivergent, and hyperdivergent groups according to their angle formed between point A-Nasion - point B (ANB) and angle formed between the Sella-Nasion (SN) plane and Gonion (Go) - Gnathion (Gn) plane (SnGoGn) values respectively.

RESULTS

Of the 999 samples, 738 (73.9%) were female and 260 (25.8%) were male patients. When compared to men, females had a higher proportion of ectopic canines. An estimated 62.3% of skeletal class I, 29.1% of skeletal class II, and 8.6% of skeletal class III cases were found to have ectopic canines. An estimated 720 (72.1%) patients were found to have maxillary ectopic canines and out of the available sample, 474 patients have horizontal growth patterns, 335 have average growth patterns and 190 patients have vertical growth patterns. Labial impaction was the commonest (65.4%) followed by palatal (24.8%). Bilateral impaction was comparatively more (51.1%) than unilateral impaction (48.2%). Maxilla was more prevalent (72.1%) as compared to the mandible (16.3%) and for both the arches it was (11.6%). Ectopic canines were identified in a total of 62.3% of cases with skeletal class I, 29.1% of cases with skeletal class II, and 8.6% of cases with skeletal class III.

CONCLUSION

The bilateral ectopic canine was mostly seen in skeletal class I and class III malocclusions, whereas, a unilateral presentation was mostly seen in skeletal class II malocclusions.

CLINICAL SIGNIFICANCE

Knowing the likelihood of a maxillary canine erupting ectopically will aid clinicians in starting with interceptive therapy since this condition necessitates complex orthodontic mechanics.

Comparison of root apex's position between unilateral and bilateral palatally impacted canines: A pilot study

INTRODUCTION

The purpose was to determine whether the location of the root apices of unilateral palatally impacted canines differs from that of bilateral palatally impacted canines using cone-beam computed tomography.

METHODS

The subjects were divided into 3 groups: a bilateral palatally impacted canine group (BPG; n = 28), a unilateral palatally impacted canine group (UPG; n = 28), and a control group (CG; n = 28) that included contralateral normally erupted canines in the UPG. After selecting the root apex in the onDemand3D program, 3-dimensional coordinates were extracted. These 3-dimensional coordinates were converted using the MATLAB program to 2-dimensional coordinates via projection on the palatal plane. Procrustes analysis was used to superimpose these 2-dimensional coordinates. The x- and y-coordinates of the root apices were used to measure the distance between the origin and root apex.

RESULTS

The distance between the root apex of the canine and the origin was 17.43 ± 1.78 mm in BPG, 17.96 ± 1.87 mm in UPG, and 13.96 ± 0.95 mm in CG. There was no statistically significant difference between UPG and BPG. However, there was a statistically significant difference between the CG and impacted groups (UPG and BPG). The same results were found for the x- and y-coordinates.

CONCLUSIONS

The location of the root apices of unilateral palatally impacted canines is similar to that of bilateral palatally impacted. The location of root apices of palatally impacted canines differs from that of normally erupted canines.

Maxillary dimensions and arch shape with palatally displaced canines

BACKGROUND/OBJECTIVES

The aim of this study was to explore the effect of palatally displaced canines on maxillary dimensions and arch shape.

METHODS

Occlusal and skeletal landmarks were plotted on cone beam computed tomography (CBCT) images of 156 orthodontic patients: 78 with palatally displaced canines (PDC) (27 left, 28 right, and 23 bilateral) and 78 controls using Mimics™ (Materialise, Belgium). Arch forms were created, and arch width, depth, and skeletal dimensions were measured. T-test (P < 0.05) was used to compare the groups. Geometric Morphometrics (GM) analysis was used to compare the groups and to explore the pattern of covariation between two sets of landmarks.

RESULTS

The unilateral PDC group showed an increased first premolar, second premolar, molar widths, and an increased molar depth. No significant difference was found in arch form. The skeletal measurements were generally larger in the PDC group, but the transverse measurements were the most significant. Discriminant Function Analysis (DFA) with cross-validation allowed an accurate classification of 85.9% of the control group and 66.7% of the PDC group. The Mahalanobis distance displayed significant differences among three combinations of groups. Strong covariance was found between the second premolar and all other landmarks.

LIMITATIONS

The small sample sizes of the stratified groups precluded recognition of statistical significance.

CONCLUSIONS

Patients with unilateral PDC displayed significantly wider first, second premolar, and first molar widths, and increased first molar depths. There were no significant differences in arch form; however, GM showed significant differences between the groups and a prominent covariance function for the 2nd premolars.

What are the intra-arch risk factors for palatally displaced maxillary canine? - Results of a case-control study

INTRODUCTION

This study aimed to identify the intra-arch risk factors for palatally displaced canine by comparing the maxillary transverse dimensions, palatal depth (PD), and arch length (AL) of the subjects with and without impacted canine using cone-beam computed tomography (CBCT).

METHODS

In this prospective case-control study, 79 CBCT images of gender- and skeletal feature-matched subjects (25 cases and 54 controls) were compared. Based on the CBCT images, maxillary transverse widths at four levels (molar basal, molar alveolar, premolar basal, and premolar alveolar), maxillary PD, and maxillary AL were measured. Group comparisons were assessed using analysis of variance (ANOVA), followed by post-hoc Scheffe's test, and risk factors were identified using univariate and multivariate logistic regression.

RESULTS

The impacted canine group showed significantly smaller molar alveolar width, premolar alveolar width, PD, and greater AL compared to the control group (P = 0.046, P < 0.001, P = 0.003, and P = 0.001, respectively). No significant difference was observed in the molar and premolar basal width measurements between the two groups. Multivariate analysis showed that impacted maxillary canine was influenced by premolar alveolar width (odds ratio (OR): 0.669), PD (OR: 0.532), and AL (OR: 1.739).

CONCLUSION

Intra-arch risk factors, such as reduced maxillary premolar transverse alveolar width, PD, and greater AL, are associated with palatally displaced canine.

Dimensional and morphologic characteristics of unilateral impacted maxillary central incisors

INTRODUCTION

This cross-sectional study aimed to investigate the crown and root characteristics of impacted central incisors compared with spontaneously erupted contralateral incisors and the influence of etiologic and local factors on their dimensions.

METHODS

Forty-five patients (22 boys, 23 girls) who underwent orthodontic treatment for unilateral impaction of maxillary central incisors were referred for cone-beam imaging. Dimensions of the impacted and contralateral incisors were assessed using Dolphin 3D software (Dolphin Imaging & Management Solutions, Chatsworth, Calif). Paired t test and linear regression were used to compare the characteristics of the impacted and contralateral teeth.

RESULTS

Contralateral and impacted central incisors showed statistically significant differences for root length (95% confidence interval [CI], 2.32-3.46; P <0.001), mesiodistal crown-root angulation (95% CI, 4.09-15.95; P = 0.001), and labiolingual crown-root angulation (95% CI, -18.69 to -4.70; P = 0.002). Etiologic factors did not alter the dimensions of incisors (95% CI, -1.17 to 0.76; P = 0.672). According to the multiple linear regression the independent variables associated with root length of contralateral and impacted incisors were sex (β = -0.904; 95% CI, -1.62 to - 0.19; P = 0.014) and the presence of impaction (β = -2.87; 95% CI, -3.67 to -2.07; P <0.001).

CONCLUSIONS

Regardless of their etiology, the impacted incisors showed roots that were 2.89 mm shorter than the contralateral incisors and had greater angulation in the mesiodistal and labiolingual directions. Girls showed a reduction of 0.904 mm (7.6%) on the lengths of roots of both impacted and contralateral central incisors. The presence of impaction led to a reduction of 25% in incisor root lengths. Approximately 30% of the impacted teeth showed crown-root angulations >20° resulting in an increased distal and labial angulation of the root apical portion.

Open and closed surgical exposure of palatally displaced canines: a cost-minimization analysis of a multicentre, randomized controlled trial

OBJECTIVE

To evaluate the costs of open and closed surgical exposure and subsequent orthodontic treatment for the correction of palatally displaced canines (PDCs).

TRIAL DESIGN

A multicentre, two-arm parallel group randomized controlled trial.

METHODS

One hundred twenty adolescents between 9 and 16 years of age, from three orthodontic specialist centres, were randomized to one of the two surgical exposure interventions. The randomization was conducted according to a two-arm parallel group 1:1 allocation ratio, using computerized lists with block randomization. In both the surgical techniques, whole mucoperiosteal flaps were raised, and bone covering the PDCs was removed. In the open technique, glass ionomer was built up on the PDC crown - reaching above the mucosa through a hole punched in the flap - to allow the canine to erupt autonomously. After eruption, the canine was orthodontically moved above the mucosa. In the closed technique, an eyelet was bonded onto the PDC, the flap was repositioned and the canine was orthodontically moved beyond the mucosa. The trial ended when the PDC was successfully aligned in the dental arch.Cost analysis was performed including costs for surgery, orthodontic treatment, emergency visits, and material, as well as costs for transports and time spent in connection with every appointment.

BLINDING

Patients and caregivers could not be blinded due to obvious limitations of the clinical setting, while outcome assessors and data analysts were blinded.

RESULTS

A cost-minimization analysis was performed since both exposure groups succeeded equally well in terms of treatment effects. The two different surgical exposures and following orthodontic treatments did not differ significantly in terms of costs.

GENERALIZABILITY AND LIMITATIONS

Costs are estimated in the Swedish setting, which needs to be considered if applying the results in other settings. Calculations of total cost do not include finishing, debonding, retention, and follow-up.

CONCLUSION

There is no significant difference in costs between closed and open surgical exposure with following orthodontic treatments in PDCs.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02186548.

Aesthetic and functional restoration of the dental arch continuity in difficult cases of impacted teeth within the frontal segment

Impacted teeth are a fairly common defect with the incidence ranging from 2.9 to 13.7%. Evaluation of the efficacy and safety of various treatment modalities in patients with impacted teeth within the frontal segment of the maxilla. The retrospective evaluation covered treatment outcomes in 81 patients with impacted teeth within the aesthetic segment. The subjects were divided into 3 groups. Patients with the impacted tooth uncovered and orthodontically repositioned in the arch were assigned to group 1. Group 2 consisted of patients with the impacted tooth qualified for extraction and the gap augmented and restored with an implant. Group 3 included subjects, who underwent en-bloc autotransplantation of the impacted tooth. In 38 group 1 subjects 47 teeth were uncovered with a mean efficacy of 58.1% (96.3% and 70% in patients below 18 yoa and adults, respectively). The excellent aesthetic treatment outcome was obtained in 75% and good in 25% of patients. In group 2 twenty-six adult subjects were treated with 100% efficacy. In 65.4% of patients, augmentation with a bone block was performed and in the remaining 34.6%, implantation and augmentation with bone granulate. In 88.3% subjects a satisfying treatment outcome was obtained. In group 3 eighteen teeth in a block were grafted with the efficacy of 88.9%. Excellent aesthetics was obtained in 56.25% of cases and good in 31.25%. Orthodontic repositioning of the impacted teeth in the arch in adult patients bears the risk of failure. Surgical treatment modalities in impacted teeth are effective and provide high aesthetics of the treatment outcome improved by prior orthodontic treatment of the concomitant malocclusion and augmentation of the vertical bone atrophy before implantation.

Comparison of Three-Dimensional and Conventional Orthodontic Imaging Modalities for Localization of Impacted Maxillary Canines in Patients With Alveolar Cleft

OBJECTIVE

The purpose of this study was to identify which diagnostic parameters related to impacted maxillary canines can be reliably detected by the conventional orthodontic radiographic modalities and which factors need to be assessed by cone-beam computed tomography (CBCT).

DESIGN

In this cross-sectional study, 8 orthodontists evaluated 7 parameters related to the position and anatomy of the impacted canines by means of 2-dimensional (2D) records. After 1 month, the same process was repeated by means of CBCT by the same clinicians.

SETTING

Qazvin University of Medical Sciences.

PATIENTS AND PARTICIPANTS

Thirty-two patients with alveolar cleft and impacted maxillary canines who had CBCT scans, lateral cephalograms, and orthopantomographs as pretreatment records.

MAIN OUTCOME MEASURE

The diagnostic accuracy of 2D and 3-dimensional (3D) radiographic modalities was compared with each other and also with the gold standard by 3 radiologists.

RESULTS

The diagnostic accuracy of 2D and 3D imaging modalities was not significantly different regarding the mesiodistal inclination of the impacted tooth (P = .09), apex anatomy (P = .10), and mesiodistal position of the apex (P = .19). Cone-beam computed tomography had significantly higher diagnostic accuracy than conventional radiographic modalities regarding overlapping the adjacent tooth (P = .001), labio-palatal and apico-coronal position of the crown tip, and root resorption of the adjacent tooth (P = .01).

CONCLUSION

The conventional orthodontic radiographic modalities were as accurate as CBCT for determination of impacted canine inclination, apex anatomy, and mesiodistal position of the apex. Cone-beam computed tomography showed higher diagnostic accuracy for other parameters.

Space conditions, palatal vault height, and tooth size in patients with and without palatally displaced canines: A prospective cohort study

OBJECTIVES:

To assess palatal vault height, tooth size, and dental arch dimensions in patients with unilateral and bilateral palatally displaced canines compared with a control group.

MATERIALS AND METHODS:

A sample of 66 patients (mean age: 11.5 ± 1.0 years) with 22 unilateral palatally displaced canines (UPDCs), 22 bilateral palatally displaced canines (BPDCs), and 22 controls (C) were consecutively recruited. All three groups had dental casts that were scanned digitally using the OrthoX three-dimensional model scanner. Tooth size, palatal vault height, dental arch width, dental arch depth, dental arch length, and dental arch space were measured by the same examiner using the GOM software. Remeasurements were made in 10 randomly identified patients.

RESULTS:

The palatal vault height was significantly lower in the BPDC group compared with controls. A significantly smaller mesial-distal crown width and, in general, more spacing in the maxilla were found in the UPDC and BPDC groups. No differences in arch length or arch width at the molar region were seen between the groups, while the arch length at the canine region was smaller in the UPDC and BPDC groups. However, this was observed in BPDC patients with both deciduous canines present and in most UPDC patients where the deciduous canine was present, compared with the control group, who had more permanent canines present.

CONCLUSIONS:

Patients with PDC had greater reduction in tooth size compared with the control group. The arch length and arch width were similar in patients with and without PDC.

Differences in the Eruption Angle of Palatally Displaced Canines in Klinefelter Syndrome: a Retrospective Study on Panoramic Radiographs

Objective

To investigate the eruption angle of maxillary canine in patients with Klinefelter syndrome (KS) in which high prevalence of palatally displaced canine anomaly (PDC) has been found by clinical assessment.

Subjects and Methods

The sample consisted of 37 KS males aged 20-34 years (mean 27 years) and the control group which consisted of 78 healthy males aged 20-27 years (mean 23 years). A pioneer method was used to measure the eruption angle. It was based on determining the topographic construction of mandibular gonion line called GO-GO method on panoramic radiograph.

Results

The mean of eruption angle was increased for 10.58° in the right side and 9.69 ° in left side in patients with KS compared to those in the control group. The difference of mesioangular inclination of palatally displaced canines in Klinefelter patients was statistically significant (p< 0.01). When eruption angle in the control group was compared to Klinefelter patients, the statistical difference was confirmed for respective sides (P <0.01 for both).

Conclusions

The difference between eruption angle values in KS patients as well as in those belonging to the control group seemed to identify a developmental disturbance, thus confirming the fact that an extra X chromosome has an influence. The GO-GO method might be used for males when it is difficult to define occlusal planes, or for comparison. If this method is used, the eruption angular values should not exceed 56.74°.

Associations between occlusion, jaw relationships, craniofacial dimensions and the occurrence of palatally-displaced canines

BACKGROUND AND PURPOSE

Cephalometric and arch measurements might predict the occurrence of a palatally-displaced impacted maxillary canine (PDC). Despite their clinical importance, studies in this regard are limited and controversial.

METHODS

In this case-control study, 35 PDC patients and 77 controls aged over 13 years were examined. Eleven cephalometric measurements: N-S, ANS-PNS, ANS-N, S-N-ANS, facial angle (FH/NPog), SNA, SNB, Y-axis (SN/SGn), gonial angle, Go-Gn/SN, and Jarabak Index were performed. The maxillary and mandibular intermolar and interpremolar widths were measured. Patients' sagittal skeletal relationships and centric occlusions (molar) were measured by radiographic and cast examinations. The differences between the two groups in terms of the above-mentioned cephalometric and anatomic variables were assessed using Chi² and Mann-Whitney U-tests (α=0.05).

RESULTS

Chi² showed a significant negative association between dentoalveolar class I (molar) and PDC occurrence (P=0.018), but not between PDC and skeletal sagittal relationships. Facial angle (FH/NPog) and Y-axis (SN/SGn) were more obtuse in patients with PDC (P<0.05). No arch dimensions differed between the two groups.

CONCLUSIONS

PDC tends to accompany molar class II/III but is not associated with upper or lower jaw widths or lengths. Vertical dimensions might be smaller in PDC patients. Some variables were inconclusive and need future assessments.

Triplets with bilateral palatally displaced canines in association with third molar agenesis: an example of biologically related dental anomaly patterns?

This case series shows male triplets with similarly positioned palatally displaced canines and agenesis of third molars. It supports findings reported previously in the literature suggesting a genetic origin for the palatally displaced canine and other dental anomalies which may be biologically related.