Qualitative and quantitative three-dimensional evaluation of maxillary basal and dentoalveolar dimensions in patients with and without maxillary impacted canines

Epidemiological and imaging characteristics of impacted maxillary incisors and effect on root development

Despite extensive research on maxillary impacted canines, studies specifically investigating maxillary impacted incisors remain limited. This retrospective study aimed to determine the prevalence of impacted teeth among adolescent orthodontic patients, analyze the imaging characteristics of maxillary impacted incisors, and evaluate factors influencing root development. From a cohort of 2163 underage patients who attended the children malocclusion special clinic between August 2022 and July 2024, individuals with impacted teeth were identified and their clinical data were collected. Subsequently, detailed analyses were conducted on impacted maxillary incisors using high-quality Cone-beam computed tomography (CBCT). There were 157 patients with 205 impacted teeth observed, presenting a prevalence rate of 7.26%. Maxillary canines were the most popular impacted teeth (39.51%), followed by maxillary incisors (30.24%). The tooth dilaceration demonstrated a significant relationship with the three-dimensional (3D) locations of tooth. Impacted teeth situated in low impacted depth (P < 0.05) and those with buccal-lingual (P < 0.05) or vertical (P < 0.01) orientations showed reduced susceptibility to root dilaceration. A positive correlation was observed between the Upper Incisor to Palatal Plane Angle (UI-PP) and both the probability (P < 0.05) and earlier occurrence (P < 0.01) of root dilaceration. The root length of impacted tooth was positively correlated with age (P < 0.05). Besides, the average root length of the impacted central incisors was 1.84 mm shorter than the contralateral. The prevalence of impacted teeth in our orthodontic specialist clinics was 7.26%, and 69.76% of impacted teeth were maxillary anteriors. The development of tooth roots was mainly influenced by age and 3D location. These findings enhance clinicians' understanding of impacted maxillary incisor characteristics and factors affecting the root development. The UI-PP proves to be an effective 3D location evaluation indicator. Early intervention is recommended for impacted teeth lacking sufficient space for root development, which could facilitate root development and minimize the risk of root dilaceration.

Three-dimensional assessment of the skeletal characteristics accompanying unilateral maxillary canine impaction: a retrospective cone-beam computed tomography study

BACKGROUND

Environmental and genetic factors associated with canine impaction have been extensively researched, whereas the bone characteristics in the impaction area have not been thoroughly studied. Accordingly, the objective of this investigation was to provide a skeletal assessment in terms of bone density, bone microstructure, bone volume, and palatal volume in subjects with unilaterally impacted maxillary canines.

METHODS

A retrospective design has been employed to address the aim of this study, where the initial pre-treatment cone-beam computed tomography (CBCT) scans of 30 patients with unilateral maxillary canine impaction were assessed. The obtained patients' data were equally divided according to the location of the impaction into 2 groups, one with buccally impacted canines, and another with palatal impactions, with the contra-lateral sides in both groups serving as the controls. Skeletal measurements such as bone density (BD), bone microstructure in terms of fractal dimension (FD), maxillary bone volume (MBV), and palatal volume (PV) were evaluated from the acquired CBCTs in both groups and compared to the controls.

RESULTS

With buccal impactions, significantly greater BD and FD have been reported (p < 0.001), whereas non-significant differences were found regarding the PV when compared with controls (p = 0.56). MBV was significantly greater on the non-impaction side in comparison with buccal impaction sides (p < 0.001). For palatal impactions: BD, FD, and MBV were significantly greater on the impaction sides (p < 0.001), and conversely with PV which has been reported to be significantly greater on the non-impaction sides (p < 0.001).

CONCLUSIONS

As per the obtained results, buccally impacted canines are associated with greater BD and FD, and less MBV, whereas palatally impacted canines are accompanied with greater BD, FD, and MBV, in addition to less PV, when both conditions are compared with the non-impaction sides.

Buccolingual inclination of posterior dentition in maxillary impacted canine patients using quadrant analysis - A cone-beam computed tomographic study

BACKGROUND

To examine the buccolingual inclination of maxillary posterior teeth, curve of Wilson, and transversal dimensions in palatally impacted maxillary canine patients, compared to controls by cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Pre-treatment images of 22 bilateral, 32 unilateral impacted maxillary canine patients and 30 controls were included. All patients had palatally impacted canines, with no posterior cross-bite. Data were reclassified in quadrants according to the presence of impaction, as the impaction quadrant (right and left quadrants of 22 bilateral impacted cases, and quadrants presenting impaction of 32 unilateral cases, n = 76), unaffected quadrant (quadrant without impaction in 32 unilateral cases, n = 32) and the control quadrant (right and left quadrants of 30 controls, n = 60) to evaluate the buccolingual inclination angle, transversal width, and arch perimeter. Additionally, comparisons were made regarding curve of Wilson and total arch perimeter among bilateral and unilateral impaction groups with the control group. Statistical analysis was performed by one-way ANOVA and Kruskal Wallis tests. Tukey or Dunn tests were used for comparisons between groups in pairs.

RESULTS

No significant difference was found for the buccolingual inclination of maxillary posterior teeth and curve of Wilson among groups. The buccolingual inclination of canines in the impaction quadrant was significantly lower than the other quadrants (p < 0.001). Basal bone width at the level of second premolars, and alveolar width at both premolars were significantly narrower in the impaction quadrant than in the unaffected quadrant (p < 0.05). Dental arch width at the level of first premolar was significantly decreased in the impaction quadrant compared to other quadrants (p < 0.05). Arch perimeter was significantly reduced in the impaction quadrant than in the unaffected quadrant (p < 0.05).

CONCLUSION

The presence of bilateral or unilateral palatally impacted maxillary canines did not effect the buccolingual inclination of posterior teeth, and curve of Wilson. Transverse discrepancy was evident in the impaction quadrant even in the absence of posterior cross-bite. Quadrant analysis was particularly useful in evaluating asymmetry for basal bone and alveolar bone widths in the premolar region in patients with unilateral palatally impacted maxillary canine patients.

Forced eruption in impacted teeth: analysis of failed cases and outcome of re-operation

BACKGROUND

Forced eruption of an impacted tooth usually requires surgical and orthodontic interventions to successfully bring the tooth into the dental arch. The clinical time required for a forced eruption is difficult to predict before treatment begins and success rates are affected by several factors before and after an eruption. This study was conducted to identify factors that affect the success of forced eruption, the duration of orthodontic treatment of impacted teeth, and the reasons for re-operation and forced eruption failure in a various teeth and cases.

METHODS

In this retrospective study, the records regarding the forced eruption of 468 teeth in 371 patients from June 2006 to May 2020 at the Advanced General Dentistry Department of Yonsei University Dental Hospital were initially examined. The records of 214 teeth in 178 patients who completed orthodontic treatment were included in the analysis. Data on patient demographics, tooth characteristics, orthodontic treatment duration, re-operations, and failures were collected from electronic medical records.

RESULTS

There was a significant difference in age between the success and failure forced eruption. Factors significantly affecting treatment duration were apex formation, position, rotation, and re-operation. Re-operation had a 96% success rate. The average orthodontic treatment duration was 29.99 ± 16.93 months, but the average orthodontic treatment duration for teeth that undergone re-operation was 20.36 ± 11.05 months, which was approximately 9 months shorter. Additionally, there was an interaction effect between rotation and re-operation on the duration of orthodontic treatment. The causes for failure of forced eruption in 6 cases were ankyloses (3 cases), incomplete alignment with the normal dental arch (2 cases), and a significant deviation in the impacted tooth's location (1 case).

CONCLUSIONS

To increase the success rate of forced eruption, age should be considered as a priority, and in order to predict the treatment period, the apex formation status, position in the arch, and rotation should be considered in addition to age. When determining re-operation, considering factors such as ankylosis, root curvature, and apex formation can help in the success of orthodontic treatment.

Influence of the maxillary dimensions and lateral incisor anatomy on the palatal impaction of maxillary permanent canines: A three-dimensional case-control study

OBJECTIVE

The diagnosis of impacted upper permanent canines (IUPC) is a relatively common clinical finding. The aim of this study was to investigate associations between the upper permanent canines palatal impaction, lateral incisors morphology and the maxilla bone base.

MATERIAL AND METHODS

Cone-beam tomography files from 62 subjects were divided into 2 groups: impaction group (ICG/n=31; mean age 14.3±2.4) with 45 canines impacted on the palatal side and age- and sex-matched control group (CG/n=31; mean age 14.3±2.3), with 62 normally erupted canines. Linear and volumetric measurements of the lateral incisors, linear transversal measures and the maxillary anterior perimeter were taken. Independent Student's t-test was used for intergroup analysis with correction of Bonferroni.

RESULTS

Significant differences were found for crown length and root diameter (buccal-palatal) (P<0.005). The maxillary anterior perimeter in the ICG was reduced in relation to the GC but not significantly (P=0.008). The transverse skeletal variables of the maxilla were equivalent in the intergroup comparison (P>0.005).

CONCLUSION

Smaller dimensions in the crown length and in the upper permanent lateral incisors root buccal-palatal diameter were associated with the impaction of upper permanent canines on the palatal side. The maxillary transverse morphology did not show any association with the occurrence of this condition.

Influence of the maxillary dimensions and anterior teeth anatomy on the buccal impaction of upper permanent canines: A three-dimensional case-control study

OBJECTIVE

The diagnosis of impacted upper permanent canines (IUPC) is a relatively common clinical finding. The aim of this study was to investigate the association of the buccal impaction of upper permanent canines with their dimensions and the maxilla bone base.

MATERIAL AND METHODS

Cone beam computed tomography files of 66 patients were allocated into: impaction group (ICG/n=33/mean age 15.7±3.9 years), with 44 impacted canines by the buccal side; control group (CG/n=33/mean age 15.66±3.99 years), matched for age and sex, with 66 canines normally erupted. The following measurements were obtained from ICG and CG groups: linear and volumetric canine dimensions, linear measurements of upper permanent central and lateral incisors, measurements of the anterior perimeter and transverse segments of the maxilla. Independent Student's t-test was used for intergroup analysis with correction of Bonferroni (α=0,005).

RESULTS

Higher values were found in the means of the variables regarding to the anterior teeth crowns in the ICG group, however, without a significant difference (P<0,005). The upper arch anterior perimeter of the individuals with canine impaction through buccal area was reduced compared to CG (P=0.001).

CONCLUSIONS

It can be concluded that individuals with upper buccal impacted permanent canine showed a significantly smaller anterior perimeter of the maxillary arch when compared to the control group. Although greater canine mesiodistal diameter was found in this group, there is no statistical association with the occurrence of this condition.

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.