Fractal dimension, lacunarity, and cortical thickness in the mandible: Analyzing differences between healthy men and women with cone-beam computed tomography

Morphology and spatial distribution of cortical bone canals: Evaluation of shape parameters, lacunarity, and fractal dimension in the human irradiated mandible

This study aimed to assess the spatial distribution of cortical bone canals' network through the analysis of lacunarity (Lac), fractal dimension (FD), and canal morphological parameters in the mandible (IR group, n = 7) of human patients under radiotherapy in comparison with non-irradiated younger (yC group, n = 8) and older (oC group, n = 8) individuals. Patients who underwent mandibular surgery were selected to have bone fragments removed during surgery, and undecalcified histological slides were analyzed by phase-contrast microscopy by two operators. The following morphological parameters were assessed in the Haversian canal (Ca): area (Ca·Ar, μm2), perimeter (Ca·Pm, μm), and circularity (Ca.c, #). Binary images were obtained by manually segmenting canals for Lac and FD analysis through box-counting. A total of 273 canals were segmented in the IR group, 284 in the yC group, and 60 in the oC group. Higher values for canal area and perimeter (p < 0.0001) were found for oC (7871 μm2 and 358.9 μm, respectively), followed by IR (2958 μm2 and 212.9 μm, respectively), and yC (1286 μm2 and 135.8 μm, respectively). Canal circularity was lower for oC (p < 0.0001). Lac and FD did not differ when comparing irradiated individuals with the younger and older individuals. In conclusion, cortical canals are morphologically different when comparing younger and older individuals with patients exposed to ionizing radiation. Alterations on Haversian canals after radiotherapy could have clinical implications, mostly related to vascularization. Lac and FD were reliable parameters in assessing the spatial organization of the canals within the matrix.

A fractal evaluation study of implant-supported overdentures

OBJECTIVE

The aim of this study is to evaluate the bone changes in the mandible of fully edentulous patients using two implant-supported overdentures after treatment, through fractal analysis (FA).

MATERIALS AND METHODS

A total of 27 patients who were treated with two implant-supported overdentures after using conventional complete dentures were included in our study. Panoramic radiographs taken during the use of conventional complete dentures formed the control group (n = 27), while radiographs taken 4 years (±1 month) after the overdenture treatment formed the study group (n = 27). In the panoramic radiographs taken before and after treatment, or during routine check-ups, three symmetrical regions of interest (ROI) were selected for each patient on the right and left sides: the mandibular condyle (ROI-1), the angle of the mandible (ROI-2), and the area anterior to the mental foramen (ROI-3). Each ROI measured 45 × 45 pixels, and the complexity of trabecular bone was measured using FA. The collected data were statistically analyzed.

RESULTS

The results indicated that there were statistically significant differences in fractal dimension (FD) measurements between the control and study groups for the selected ROIs (ROI-1, ROI-2, ROI-3) (P = .001). However, no statistically significant differences were found between the right and left sides in terms of FD measurements for ROI-1, ROI-2, and ROI-3 (P = .814), (P = .654), (P = .296).

CONCLUSIONS

Our findings suggest that the use of implant-supported overdentures leads to more complex trabecular bone structures in various regions of the mandible compared to the use of conventional complete dentures.

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.

Fractal Dimension and Lacunarity Analysis in the Dentulous and Edentulous Mandibular Posterior Region Using Cone-beam Computed Tomography: A Cross-sectional Retrospective Study

AIMS

This cross-sectional retrospective study was conducted to assess the differences in the microarchitecture of the trabecular bone of the posterior mandibular region at dentulous and edentulous sites with the help of fractal dimension (FD) and lacunarity using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Ninety CBCT scans were analyzed for the purpose of the present study. Inclusion criteria included subjects with unilaterally missing mandibular molars or premolars and an with intact contralateral opposing tooth. The coronal view of the dentulous and edentulous sites was used, and the region of interest (ROI) was selected 2.6 mm below the apex of the tooth present. These images were then transferred to ImageJ Software, and fractal analysis was done using the box-counting method of the FracLac plug-in. A paired samples t-test was performed to compare the means of FD and lacunarity, and a Kendall correlation was performed to check correlations. A p-value less than 0.05 was considered to indicate statistical significance.

RESULTS

Statistical analysis revealed that the mean FD of the edentulous side was significantly greater than that of the dentulous side (p-value = 0.011). Additionally, the mean lacunarity of the edentulous side was marginally significantly greater than that of the dentulous side (p-value = 0.089). A significant negative correlation was detected between the FD and lacunarity of the edentulous region (p-value = 0.017), and a marginally significant negative correlation was detected between edentulous lacunarity and dentulous lacunarity (p-value = 0.081).

CONCLUSION

The differences in occlusal forces exerted in dentulous and edentulous regions can lead to a change in the trabecular pattern of the bone in these regions. This change in the microarchitecture of bones can be detected by FD and lacunarity, which can further help us assess changes pre- and post-implant.

CLINICAL SIGNIFICANCE

The advanced technology, the assessment of microarchitecture of the bone has been made easy, using FD and lacunarity, as done in the present study. This analysis can further aid us in both pre- and post-implant analysis to prevent failure of the implant. How to cite this article: Bhoraskar M, Denny C, Srikant N, et al. Fractal Dimension and Lacunarity Analysis in the Dentulous and Edentulous Mandibular Posterior Region Using Cone-beam Computed Tomography: A Cross-sectional Retrospective Study. J Contemp Dent Pract 2024;25(6):581-587.

Titanium Alloy Implants with Lattice Structures for Mandibular Reconstruction

In recent years, the field of mandibular reconstruction has made great strides in terms of hardware innovations and their clinical applications. There has been considerable interest in using computer-aided design, finite element modelling, and additive manufacturing techniques to build patient-specific surgical implants. Moreover, lattice implants can mimic mandibular bone's mechanical and structural properties. This article reviews current approaches for mandibular reconstruction, their applications, and their drawbacks. Then, we discuss the potential of mandibular devices with lattice structures, their development and applications, and the challenges for their use in clinical settings.