Structural changes in the trabecular bone of the mandibular condyle of growing patients with sagittal jaw discrepancy treated with the twin-block appliance

The effect of mentoplate application on the condyle

BACKGROUND

The aim of the study was to investigate the changes occurring in the mandibular condyle by using mentoplate together with rapid maxillary expansion (MP-RME) treatment in the correction of skeletal class III relationship, using fractal analysis (FA).

METHODS

The sample consisted of 30 individuals (8-11 years) diagnosed with skeletal Class III malocclusion who underwent MP-RME treatment. Archival records provided cone-beam computed tomography (CBCT) images taken at two intervals: before MP-RME treatment (T0) and after treatment (T1). The CBCT images were obtained using standardized settings to ensure consistency in image quality and resolution. The trabecular structures in the bilateral condyles at both T0 and T1 were analyzed using FA. The FA was performed on these condylar images using the Image J software. The region of interest (ROI) was carefully selected in the condyle to avoid overlapping with cortical bone, and the box-counting method was employed to calculate the fractal dimension (FD). Statistical analysis was conducted to compare the FD values between T0 and T1 and to evaluate gender differences. The statistical significance was determined using paired t-tests for intra-group comparisons and independent t-tests for inter-group comparisons, with a significance level set at p < 0.05.

RESULTS

The analysis revealed no statistically significant differences in the trabecular structures of the condyles between T0 and T1 (p > 0.05). However, a significant gender difference was observed in FA values, with males exhibiting higher FA values in the left condyle compared to females at both T0 and T1 (p < 0.05). Specifically, the FA values in the left condyle increased from a mean of 1.09 ± 0.09 at T0 to 1.13 ± 0.08 at T1 in males, whereas in females, the FA values remained relatively stable with a mean of 1 ± 0.09 at T0 and 1.03 ± 0.11 at T1.

CONCLUSION

The findings indicate that MP-RME therapy does not induce significant alterations in the trabecular structure of the mandibular condyle. These results suggest the treatment's safety concerning the structural integrity of the condyle, although the observed gender differences in FA values warrant further investigation.

Evaluation of mandibular osseous structure in patients with mandibular asymmetry: a fractal analysis study

OBJECTIVE

We evaluated the effect of mandibular asymmetry on the trabecular structure of the mandible as measured through fractal analysis (FA).

STUDY DESIGN

We divided a sample of 105 patients with skeletal class I occlusion, cervical vertebral maturation CS6, and skeletal vertical dimension ratios within normal limits into right asymmetric, left asymmetric, and symmetric groups. We performed FA on 6 bilateral regions of interest on panoramic radiographs of the patients and calculated the mean fractal dimension (FD) for each region. We performed the Wilcoxon signed-rank and paired t tests to compare the significance of differences in FD between sides within each group and between groups for all regions. Statistical significance was established at P < .05.

RESULTS

We found statistically significant differences in mean FD values between the right and left condyles of the 2 asymmetric patient groups. The FD was greater in the left condyle of patients with right asymmetry and in the right condyle of patients with left asymmetry. The right condyle had a significantly greater FD in left asymmetric patients than in right asymmetric patients.

CONCLUSIONS

The results of FA indicate that asymmetry is characterized by an increase in the mean FD of the condyle that is responsible for the asymmetry. Fractal analysis can be a valuable diagnostic technique in distinguishing trabecular differences in the condylar areas of asymmetric individuals.

Comparison of the effects of removable functional appliance therapy applied in pubertal and postpubertal periods: A retrospective cephalometric and fractal analyses study

INTRODUCTION

In this study, we compared the effects of functional treatment with Twin-block appliance on the bony architectures of the maxilla and mandible by fractal dimension (FD) analysis, and the skeletal and dentoalveolar effects by cephalometric analysis, in pubertal and postpubertal patients with Class II malocclusion.

METHODS

This study comprised 60 patients who underwent Twin-block treatment. Group 1 consisted of 30 patients in the pubertal period (6 boys and 24 girls; mean age 12.27 ± 1.35 years), whereas group 2 consisted of 30 patients in the postpubertal period (6 boys and 24 girls; mean age 13.73 ± 1.51 years). FD analysis was performed on the patients before and after Twin-block panoramic and lateral cephalometric radiographs. Cephalometric analysis was also conducted. Paired and Student t tests were used to compare the parametric data, and Wilcoxon signed rank and Mann-Whitney U tests were conducted to compare the nonparametric data.

RESULTS

SNB, Pg-N, N-Me, ANS-Me, IMPA, L1/NB, Co-Gn, Go-Gn, S-Go, Co-Go, and Go-Me significantly increased in both groups after treatment. FD values of tuber, condyle, and molar regions significantly decreased in group 1, whereas no significant differences were observed in group 2 after treatment.

CONCLUSIONS

In the pubertal period, the Twin-block appliance resulted in skeletal correction by causing bone remodeling and reshaping in both jaws along with the dentoalveolar correction. In the postpubertal period, Twin-block had no significant effect on the bone trabecular arrangement in the investigated areas but produced cephalometric improvement to a certain extent with lower skeletal and higher dental impact.

Effects of reverse headgear therapy on mandibular trabecular structure: A fractal analysis study

OBJECTIVES

The aim of this study was to assess the effects of reverse headgear (RHG) treatment combined with rapid maxillary expansion (RME) on the trabecular structure of the mandibula using fractal dimension (FD) analysis.

METHODS

Forty-four individuals with skeletal Class III malocclusion were selected from the archives and divided into two groups as patients who underwent treatment with RME + RHG (RHG-G, 22 patients) and untreated control group (C-G, 22 patients). The before (T0) and after (T1) treatment lateral cephalometric and panoramic radiographs were collected in the RHG-G and in the control group, radiographs obtained with similar time intervals were grouped as T0 and T1. Cephalometric and FD analysis was conducted on T0 and T1 lateral cephalometric and panoramic radiographs. The intragroup comparison of cephalometric and FD data was performed using paired t test and Wilcoxon Signed Ranks test, while independent t test and Mann-Whitney U test were used for intergroup comparison.

RESULTS

C-G had higher FD values in the right mandibular corpus and left mandibular ramus values at T0 (P < .05). The only significant difference in the intragroup comparisons was detected in the FD values of the right mandibular corpus in the C-G (P < .05). No significant differences were found in the FD between the groups in any of the areas measured (P > .05).

CONCLUSIONS

RME + RHG therapy did not cause any significant trabecular changes in the mandibula when compared to the control group.