Alveolar bone thickness and fenestration of incisors in untreated Korean patients with skeletal class III malocclusion: A retrospective 3-dimensional cone-beam computed tomography study

Correlation of alveolar bone thickness and central incisor inclination in skeletal Class I and II malocclusions with different vertical skeletal patterns: A CBCT study

INTRODUCTION

This study aimed to assess the alveolar bone thickness (ABT) and labiolingual inclination of maxillary and mandibular central incisors in patients with Class I and II skeletal patterns with normal-angle, high-angle, and low-angle vertical patterns.

METHODS

The study sample consisted of 200 cone-beam computed tomography scans of patients with skeletal Class I and II malocclusions. Each group was further divided into low-angle, normal-angle, and high-angle subgroups. Labiolingual inclinations of maxillary and mandibular central incisors and ABT were measured at 4 levels from the cementoenamel junction in the labial and lingual surfaces. The Kolmogorov-Smirnov test, independent t test, 2-way analysis of variance, and Spearman's correlation test were applied for statistical analyses.

RESULTS

The only significant difference between Class I and II groups regarding the ABT was found at the labial side of the maxillary central incisor, 9 mm apical to the crest. At this level, the mean ABT was 0.87 mm in patients with a skeletal Class I malocclusion, which was significantly greater than that in patients with a skeletal Class II malocclusion with a mean ABT of 0.66 mm (P = 0.02). Comparisons among the vertical subgroups revealed that on the labial and lingual sides of the mandible, as well as the palatal side of the maxilla, significantly thinner alveolar bone was found in patients with high-angle growth patterns than those with normal-angle and low-angle patterns in both sagittal groups (P <0.05). Significant weak to moderate correlations were found between ABT and tooth inclination (P <0.05).

CONCLUSIONS

Significant differences in ABT covering central incisors between patients with skeletal Class I and II malocclusion are merely observed at the labial surface of the maxilla, 9 mm apical to the cementoenamel junction. Compared with patients with normal-angle and low-angle, those with a high-angle growth pattern and Class I and II sagittal relationships have thinner alveolar bone support around maxillary and mandibular incisors.

Alveolar bone height changes in the anterior tooth region before and after orthodontic treatment for Angle's Class II division 1 malocclusion and related factors

BACKGROUND

The aim of this study was to observe the alveolar bone height changes in the anterior tooth region after orthodontic treatment for Angle's Class II division 1 malocclusion.

METHODS

Ninety-three patients treated from January 2015 to December 2019 were retrospectively analyzed, of whom 48 received tooth extraction and 45 did not.

RESULTS

After orthodontic treatment, the alveolar bone heights in the anterior tooth regions of tooth extraction and non-extraction groups decreased by 67.31% and 66.94%, respectively. Except for the maxillary and mandibular canines in the tooth extraction group as well as the labial side of maxillary anterior teeth and the palatal side of maxillary central incisors of the non-extraction group, the alveolar bone heights of other sites significantly reduced (P<0.05). The reduction in the alveolar bone height of the tooth extraction group significantly exceeded that of the non-extraction group on the palatal side of maxillary incisors and the lingual side of mandibular anterior teeth (P<0.05).

CONCLUSIONS

Alveolar bone height in the anterior tooth region decreases after orthodontic treatment for Angle's Class II division 1 malocclusion, being closely related to tooth position together with movement direction and amplitude.

Understanding root fenestration: A systematic scoping review of prevalence and clinical factors

The aim of this systematic scoping review is to explore the literature on root fenestration prevalence and its possible etiologic, aggravating and predisposing clinical factors. A systematic search was conducted in 5 electronic databases, by two independent reviewers, without any language and date restrictions. Forty-six full-text records were included in the study, out of which 27 were used for prevalence analysis and 42 for clinical factor analysis. The results suggest that the literature is heterogenous, with major differences in the study protocols and results' presentation, providing limited information regarding root fenestration prevalence and possible racial distribution patterns. Further documentation is also required regarding clinical parameters that may affect root fenestration's presence and severity. Despite their few limitations, retrospective cone beam computed tomography studies with high-resolution protocols, as well as open flap studies for direct observation of possible root fenestration sites, seem the most reliable methods to better comprehend its presence and possible distribution patterns.

Evaluation of alveolar bone morphology of incisors with different sagittal skeletal facial types by cone beam computed tomography: A retrospective study

Background

Safe orthodontic tooth movement should be performed within the alveolar bone. The purpose of this study was to evaluate the morphology of the alveolar bone of incisors.

Materials and methods

This retrospective study included pretreatment cone beam computed tomography of 120 patients with malocclusion. Patients were divided into 4 groups (Class I, Class II division 1, Class II division 2 and Class III) according to the subspinale-nasion-supramental (ANB) angle and occlusal relationship. The sagittal root positions, anterior and posterior root-cortical bone angles (AR-CA and PR-CA), root-crown ratios (RCR) and alveolar bone thickness were evaluated.

Results

The sagittal root positions were mainly positioned against the labial cortical plate in the maxillary incisors of the Class II division 2 group and engaged by both the labial and palatal cortical plates in the mandibular incisors of the Class III group. The AR-CA was lower than that in the other groups (P < 0.01) in the maxillary incisors of the Class II division 2 group, and the AR-CA and PR-CA were lower than those in the other groups (P < 0.01) in the mandibular incisors of the Class III group. The alveolar thickness showed no significant difference between the Class II division 1 group and the Class I group (P > 0.05), the middle and lower anterior alveolar thickness (LAAT and MAAT) were lower than those in other groups (P < 0.01) in the maxillary incisors of the Class II division 2 group, and the alveolar thickness at the measurement sites of the middle and lower line were lower than those in other groups (P < 0.01) in the mandibular incisors of the Class III group. The RCR had a moderate positive correlation with the LAAT.

Conclusion

Based on several limitations, this study found that maxillary incisor roots were at risk of penetrating the alveolar bone of Class II division 2 patients, and mandibular incisors may have a relatively small range of safe movement on both the labial and lingual sides of Class III patients during orthodontic treatment.

Evaluation of the correlation between facial index and the cortical bone thickness of the maxilla and mandible-A computer tomography based study

OBJECTIVES

cortical bone thickness confines the position of teeth and thus can be a limiting factor for orthodontic tooth movement. The study is aimed to correlate the cortical bone thickness of the maxilla and mandible with that of different face types, viz; dolichofacial, brachyfacial, and mesofacial.

METHODS

Forty CT scans were analysed for the face types and were grouped into dolichofacial (13), brachyfacial (13) and mesofacial (14) face types. The scans were measured for the right and left side buccal and lingual cortical bone thickness at the central incisor, first and second molar regions on both the maxilla and mandible. Other parameters like basal cortical bone thickness, height, and width of cortical bone were also measured. To determine the correlation and difference between the different parameters, the obtained data was subjected to the correlation coefficient, t test, and ANOVA statistical analysis.

RESULTS

Maxillary buccal cortical bone thickness of central incisors was found to be highly correlated to facial index with a correlation coefficient of - 0.833 * *. Mandibular buccal bone thickness correlated with face type and cortical bone thickness at the central incisor, first, and second molars by-0.531 * *, - 0.474 * *, and - 0.589 * *, respectively. There was a significant difference between the right and left side cortical bone thickness (p < 0.05) and also for all the parameters amongst the different face types (p < 0.05).

CONCLUSION

There exists a definite correlation between the face type and the certain anatomical measurements of cortical bone morphology. Dolichofacial face types show thin buccal cortical bone, which implies the limitation of orthodontic tooth movement in these types of individuals.

The Accuracy of Lateral Cephalogram for Measuring Alveolar Bone Thickness and Root Diameter on Mandibular Incisors

Background: The objective of the study was to ascertain whether the alveolar bone and root of the mandibular central incisor measured from cephalograms can represent the same measurements of both mandibular central and lateral incisors from CBCT. Methods: A total of 38 sets of CBCT images and cephalograms before treatment were selected for this study. Thicknesses included alveolar bone, cortical bone, and cancellous bone at the labial and lingual sides. Root diameter and total root-bone thickness were also evaluated. The measurements were performed at 3, 6, and 9 mm from the cemento-enamel junction. Heights included labial bone height and lingual bone height. All measurements were performed on cephalograms and CBCT images of the mandibular central incisor (L1CT) and mandibular lateral incisor (L2CT). The data were statistically analyzed using one-way ANOVA and Bonferroni tests (p < 0.01) to compare the cephalograms, L1CT, and L2CT. Results: The cephalograms presented thicker alveolar bone and cortical bone (labial: 0.16−0.31 mm, lingual: 0.14−0.29 mm; p < 0.001) as well as higher alveolar crest (labial: 0.46−0.48 mm, lingual: 0.38−0.39 mm; p < 0.001) than the CBCT images on both the labial and lingual sides, whereas lingual cancellous thicknesses were not significantly different (p = 0.257). The cephalograms presented greater total root-bone thicknesses than L1CT (0.19−0.30 mm; p < 0.001), whereas the cephalograms traced thinner roots than L1CT (0.18−0.23 mm; p < 0.001) and L2CT (0.39−0.59 mm; p < 0.001). Conclusion: Lateral cephalograms cannot represent both mandibular central and lateral incisor dentoalveolar thicknesses, heights, and root diameters the same as CBCT. However, the differences were less than 0.5 mm.

Retreatment of an orthognathic camouflaged case by total lower arch mesialization using temporary anchorage device

Mandibular tooth extractions for camouflage treatments in borderline Class III patients may end up with unpleasing esthetic results which may lead the patient seeking further complicated retreatments. In this case report, we presented a patient's retreatment with a combined orthodontic and orthognathic surgery treatment plan. The treatment strategy involved an innovative temporary anchorage device (TAD)-based method for total mandibular arch mesialization instead of space reopening for first lower premolar replacement with implants. In the current case report, orthognathic management of a Class III adult female is discussed. The patient had a history of an esthetically unsuccessful previous camouflaged orthodontic treatment with two lower premolar extractions. She was prepared for orthognathic surgery using an innovative custom-made sliding jig based on miniscrews for total mandibular arch mesialization with the aim of dental arch decompensation. After gaining the optimal dental arch discrepancy, the patient had orthognathic surgery (maxillary advancement and mandibular setback and advancement genioplasty). Total mandibular dental arch mesialization with the aim of dental arch discrepancy preparation was successfully conducted using TADs. By means of the innovative miniscrew-anchored sliding jig, the patient's satisfactory esthetic and occlusal results were obtained in 22 months. With innovative application of the miniscrews, more practical and reasonable alternatives are available to replace conventional and complicated treatment plans such as space reopening for implants in patients with unsuccessful previous orthodontic therapies.