Comparison of the collum angle of incisors and canines in skeletal malocclusions - A CBCT study

Are morphological and morphometric characteristics of maxillary anterior region and nasopalatine canal related to each other?

OBJECTIVES

The main purpose of this article was to clarify the relationship of anterior bone and tooth morphology with NPC. The anatomical features of the NPC region in three dimensions from coronal, axial, and sagittal directions were analyzed using CBCT and the effects of age, gender, sagittal root positions (SRPs) of central teeth, anterior overbite depth (AOD), central incisor (CI)/palatal plane (PP) angle, NPC/PP angle, and collum angles (CA) on NPC were evaluated in a group of the Turkish population.

MATERIALS AND METHODS

In this retrospective study, CBCTs of a total of 330 individuals between the ages of 17 and 82 were evaluated. The effects of SRP, AOD, CI/PP angle, NPC/PP angle and CA on the anatomical features of NPC were examined on the basis of age and gender. Descriptive statistics, Kolmogorov-Smirnov, Chi-square, Wilcoxon, Mann-Whitney-U, Kruskal-Wallis, and Spearman correlation tests were used. p values of < 0.05 were accepted as statistically significant.

RESULTS

While the SRPs, CI/PP angle, NPC/PP angle, CA, and age did not differ statistically according to NPC shape (p > 0.05), NPC shape varied according to gender and AOD (p < 0.05). It was found that cylindrical NPC (32.8%) was more common in females, while conical-shaped NPC (30.7%) was more common in males (p < 0.01). While most conical NPC was detected in individuals with Class I overbite depth, cylindrical NPCs were found in Class II and III individuals (p < 0.01).

CONCLUSIONS

The results showed that gender and AOD are influential factors on NPC shape. While conical-shaped NPC is more common in individuals with bite depth incisal, cylindrical-shaped NPC is more likely to be seen in individuals with middle and cervical thirds.

Cone Beam Computerized Tomographic Analysis of Collum Angle of the Maxillary Central Incisors in Different Types of Malocclusion: Comparative Assessment in Saudi, Jordan and Egypt Subpopulation

Background: The collum angle (CA) is an extremely significant for patients who are undergoing orthodontic, dental implant restoration, prosthodontic and periodontic treatments. Aim and Objectives: To determine and compare the mean CA for maxillary central incisor in different types of malocclusion utilizing 3D Cone Beam Computerized Tomography (CBCT) images. The additional objectives were to determine and compare the mean CA for maxillary central incisor based upon the demographic characteristics among Saudi, Jordan and Egypt subpopulation and to test for significant differences in the CA of maxillary central incisor with different molar malocclusions. Methodology: A total of 400 CBCT images were included from the radiology archive at the College of Dentistry, Jouf University (Sakaka, Saudi Arabia). The CBCT images were divided into four groups based upon molar classifications. The selected records were used for the measurement of CA of maxillary central incisor using the measurement tool built into 3D:OnDemand software. Statistical analysis was done using independent t test and ANOVA to examine the differences between gender and races. Results: The mean CA for Class II div 2 exhibited significantly higher crown-root variation as compared other groups (p < 0.0001). Males sample showed greater value of CA for each group as compared to the females and this difference was statistically significant for all the groups other than for Class I (p < 0.05). The post hoc pairwise comparisons between the races showed statistically insignificant findings (p > 0.05). Significant difference was found on pairwise comparisons among different malocclusion groups other than for group Class I/Class II div 1 (p < 0.05). Conclusion: The CA of Class II div 2 group was the greatest as compared to other malocclusion groups. Males sample showed greater value of CA for each group as compared to the females and this difference was statistically significant for all the groups other than for Class I. Statistically insignificant difference was noted for the mean CA among different races whereas significant difference was found on pairwise comparisons among different malocclusion groups other than for group Class I/Class II div 1.

Collum angle of the anterior teeth: A systematic review and meta-analysis

OBJECTIVES

To assess and evaluate the collum angle (CA) of the anterior teeth of the permanent dentition.

METHODS

A search in seven databases for articles that had measured the CA in sagittal malocclusions was conducted until November 30, 2021. The risk of bias was assessed using the Modified Newcastle Ottawa scale. CA measurements using Cone Beam Computed Tomography or lateral cephalograms were included. The CA data were summarized by random-effects inverse generic meta-analyses.

RESULTS

Qualitative analysis of the 17 selected articles revealed that four were rated as "very good," 12 as "good" and 1 as "satisfactory." CA was 4.7° (95% CI of 3.1 to 6.4) and 2.0° (95% CI of 0.1 to 3.9) greater in Class II division 2 and Class III malocclusions respectively, than in Class I malocclusion cases.

CONCLUSION

Majority of the studies were rated as good or very good. Most studies evaluated the CA of the maxillary central incisors in Class II division 2 malocclusion. Studies assessing other maxillary anterior and mandibular anterior teeth are required.

CLINICAL SIGNIFICANCE

Practice of esthetic dentistry for teeth with increased CA is of clinical importance since the angle would determine the longevity and esthetic/cosmetic success of the rehabilitation. Placement of dental implants in areas of missing teeth with increased collum angle leads to excessive stress between the fixture and abutment leading to gingival recession. Thus, knowledge about the collum angle of anterior teeth and its variations in sagittal malocclusions would enable precise treatment planning in the field of esthetic dentistry.