Fractal dimension and mandibular cortical width in normal and osteoporotic men and women.

Objective: To verify whether fractal dimensions (FD) on the mandibular trabecular and cortical bone and mandibular cortical width (MCW) differ between patients with normal bone mineral density (BMD) and osteoporosis.

Study Design: In this retrospective study, 133 dental panoramic radiographs from men aged >60 years and postmenopausal women with a bone densitometry report of the lumbar spine and hip classified as either normal or osteoporotic were selected. Fractal dimensions of five standardized trabecular and cortical mandibular regions of interest and mandibular cortical width were measured on the panoramic radiographs by an experienced oral radiologist, blinded to the densitometric diagnosis. The following statistical analyses were performed: ANOVA and a forward logistic stepwise regression to verify associations between dental panoramic measurements and the densitometric diagnosis. P values less than .05 indicated statistical significance.

Main Outcome Measures: Fractal dimension and mandibular cortical width.

Results: Differences were found in the FD values on mandibular cortical bone and MCW between patients with normal BMD and with osteoporosis, but not in the FD values of trabecular bone. The odds of having lower mean values of MCW and FD on cortical bone were 2.16, 3125 and 1005 times in osteoporotic patients, respectively, compared with patients with normal BMD.

Conclusion: The values of FD analysis on mandibular cortical bone and MCW were lower in women with osteoporosis. A well-adjusted logistic regression model showed that cortical bone measurements might be considered as auxiliary tools to referring patients for DXA exam.