Regional mandibular trabecular alterations in rheumatoid arthritis: a fractal analysis study using panoramic radiographs

Background

To examine the regional alterations of mandibular trabecular bone microarchitecture in RA patients using the analysis of panoramic radiographs based on the fractal dimension (FD)‚ and to assess the effect of the duration of glucocorticoid (GC) treatment․

Methods

In this retrospective study‚ 96 RA patients and 96 controls were recruited․ The FD of four standardized regions of interest (ROIs) was measured using ImageJ: the condyle‚ the mandibular angle‚ the two trabecular areas of the corpus (including the area anterior to the mental foramen)․ Group comparisons were performed using non-parametric tests and multivariable logistic regression‚ adjusted for age and sex․ A subgroup analysis based on age (≥ 40 years‚ respectively) was used to rule out residual confounding by age․

Results

FD was considerably lower in the RA group compared to the control group in all regions of interest (p < 0․001)․ The differences in the condylar region and the trabecular region anterior to the mental foramen had the largest differences and retained their importance after controlling for other factors․ These findings were similar in the age-restricted subgroup analyzes and did not have an important association (p > 0․05) with GC duration of use․

Conclusion

RA is associated with site-specific deterioration of mandibular trabecular microarchitecture‚ particularly in the condylar region and the trabecular region anterior to the mental foramen․ FD analysis of panoramic radiographs may be a useful imaging biomarker for detecting skeletal involvement in the RA population․