Anterior Maxillary Labial Bone Thickness on Cone Beam Computed Tomography

Periodontal outcomes of surgically exposed and orthodontically aligned buccally impacted maxillary canines: A systematic review and meta-analysis

OBJECTIVE

To compare the periodontal outcomes of surgically exposed and orthodontically aligned buccally impacted maxillary canines to spontaneously erupted maxillary canines.

DATA SOURCES

An unrestricted search was carried out of indexed databases (Medline, EMBASE, Web of Science and Scopus), reference lists of included studies, and grey literature published until December 2023.

DATA SELECTION

Observational and experimental studies that addressed the focused question 'Do periodontal outcomes of buccally impacted maxillary canines that were surgically exposed and subsequently extruded and aligned using orthodontic alignment, differ from those of spontaneously erupted maxillary canines?' were included.

DATA EXTRACTION

Study screening, selection and data extraction were performed independently by two authors, with disagreement resolved by a third reviewer. The risk of bias was assessed using the JBI Critical Appraisal Checklist and GRADE approach.

RESULTS

A total of 857 citations were found and five studies were eligible for inclusion. Supragingival plaque accumulation and gingival inflammation were similar between impacted canines and their contralaterals in most studies. Meta-analyses revealed no significant differences in keratinised tissue width (prospective studies: MD = -0.28, 95% confidence interval [CI] = -1.13-0.56, I² = 78%; retrospective studies: MD = 0.61, 95% CI = -1.51-2.72, I² = 94%). However, a meta-analysis of prospective studies showed slightly greater mean probing depth for impacted canines compared to their contralateral canines (prospective studies: MD = 0.16, 95% CI = 0.04-0.28, I² = 0%). The evidence certainty for keratinised tissue width and probing depth outcomes was low.

CONCLUSION

Surgically exposed and orthodontically aligned buccally impacted canines have slightly greater probing depths, potential bone loss and increased clinical crown length, compared to their counterparts. However, these small differences (<1 mm) are unlikely to be clinically significant.

Evaluation of Optimal Insertion Sites and Angles for Orthodontic Mini-Implants at the Anterior Nasal Spine Region Based on Cone-Beam Computed Tomography

BACKGROUND

To infer the optimal angulation and height level of mini-implant insertion in the anterior nasal spine (ANS) region from alveolar bone depth (BD) and labial cortical bone thickness (CBT) through cone-beam computed tomography (CBCT), the influences of sex, age, and growth pattern on BD, CBT, and the starting point of the ANS were examined.

MATERIAL AND METHODS

BD and CBT were measured on CBCT median sagittal images at specific angles (0, 15, 30, 45, and 60 degrees) to simulate the angulation of insertion. The height level of the first axial image with obvious bone ridge was recorded as the start of ANS.

RESULTS

The average height of ANS start was 9.42 mm from the alveolar bone crest between the central incisors. The variations in height level and insertion angle combined, or either of them individually, significantly influenced BD and CBT, demonstrating overall decreasing trends (p < 0.001). BD was not influenced by sex, age, or growth pattern (p > 0.05). However, CBT was found to be correlated with sex and growth pattern, while the height level of ANS start was associated only with growth pattern, particularly in hypodivergent patients (p < 0.05).

CONCLUSION

The recommended insertion height level is 14-16 mm from the alveolar bone crest and the recommended angulation is 30-45°. An innovative inequity in the relationship between a certain height level and the insertion angulation is proposed.

Evaluation of cuspid cortical anchorage with different sagittal patterns using cone-beam computed tomography: a retrospective study

BACKGROUND

No studies have focused on cortical anchorage resistance in cuspids, this study aimed to characterize the cortical anchorage according to sagittal skeletal classes using cone-beam computed tomography (CBCT).

METHODS

CBCT images of 104 men and 104 women were divided into skeletal class I, II, and III malocclusion groups. Skeletal and dental evaluations were performed on the sagittal and axial cross-sections. One-way analysis of variance followed by least significant difference post-hoc tests was used for group differences. Multiple linear regression was performed to evaluate the relationship between influential factors and cuspid cortical anchorage.

RESULTS

All cuspids were close to the labial bone cortex in different sagittal skeletal patterns and had different inclinations. There was a significant difference in the apical root position of cuspids in the alveolar bone; however, no significant difference in the middle or cervical portions of the root was found between different sagittal facial patterns. The middle of the cuspid root was embedded to the greatest extent in the labial bone cortex, with no significant difference between the sagittal patterns. For all sagittal patterns, 6.03 ± 4.41° (men) and 6.08 ± 4.45° (women) may be appropriate root control angles to keep maxillary cuspids' roots detached from the labial bone cortex.

CONCLUSIONS

Comparison of skeletal class I, II, and III malocclusion patients showed that dental compensation alleviated sagittal skeletal discrepancies in the cuspid positions of all patients, regardless of the malocclusion class. Detailed treatment procedures and clear treatment boundaries of cuspids with different skeletal patterns can improve the treatment time, periodontal bone remodeling, and post-treatment long-term stability. Future studies on cuspids with different dentofacial patterns and considering cuspid morphology and periodontal condition may provide more evidence for clinical treatment.

Cone Beam Computed Tomography (CBCT) Evaluation of Alveolar Bone Thickness and Root Angulation in Anterior Maxilla for Planning Immediate Implant Placement

OBJECTIVE

 This retrospective study aimed to measure the labial, palatal, mesial, and distal bone thickness around maxillary central and lateral incisors and canines and height from crest to apex, using cone beam computed tomography (CBCT) images and compare the results based on gender. The second objective of the study was to measure root angulation on CBCT images and its relation with the labial cortical thicknesses.  Material and Methods: After the Institutional Review Board (IRB) approval, a total of 140 CBCT volumes were included in this study according to the set criteria. On each scan, right-side maxillary central, lateral incisors, and canine were selected for the measurements. All the measurements were done at three levels at the alveolar crest (L1), mid-root (L2), and apical region (L3) for each tooth.  Results: The Student's t-test was performed to compare the result of buccal, palatal, mesial, and distal bone thickness, angulation, and height of all subjects. Buccal alveolar bone thickness was minimum at the mid-root region, and the palatal bone thickness was minimum at the crestal region. The mesial bone thickness was minimum at the mid-root level, and distal bone thickness was minimum at the crest level. The available bone height was maximum at the lateral incisor and equal for the central incisor and canine. The canine was the most angulated tooth.

CONCLUSION

 Cone beam computed tomography is a reliable imaging modality to evaluate pre-surgical immediate implant sites and measure alveolar bone thickness. The canine was the most angulated tooth with more buccal alveolar bone thickness.