Relationship between body mass index and local quality of mandibular bone structure in elderly individuals.

BACKGROUND: Human bones decrease in density and increase in porosity beginning at about the third decade of life. The objective of this study was to determine whether mandibular bone mineral density (BMD) and some linear radiomorphometric measurements on dental panoramic radiograph (DPR) are correlated with different categories of body mass index (BMI) in elderly individuals. METHODS: Cortical width at gonion (GI), at antegonion (AI), and below mental foramen (MI) and the appearance of the cortex of the lower border of the mandible distal to the mental foramina due to resorptive changes (mandibular cortical index [MCI]) were measured bilaterally on the mandible on 136 DPRs of elderly individuals. Using DPRs and copper stepwedge, mandibular BMD was investigated densitometrically. All BMD values were expressed in equivalents of the actual stepwedge thickness. The patients with BMIs from 20 to 25 kg/m(2) were classified as category 1 (the generally accepted range of normal BMI), and the patients with BMIs higher than 25 were classified as category 2 (heavy individuals with a heavy skeleton and a large amount of fat in the body). RESULTS: The results revealed statistically significant differences in all measured indices between different BMI categories (p <.05 for MI; p <.001 for GI and AI). Statistically significant differences were also found in BMD values between different BMI categories (p <.05); the differences were more pronounced in women. The patients with MCI category 3 had significantly lower BMD values in comparison to MCI category 2 (p <.01). Intraobserver agreement in GI, AI, MI measurement, and MCI assessments was excellent. CONCLUSIONS: Heavy people have higher BMD and higher values in linear radiomorphometric measurements than lighter people.

Three-month change in the radiodensity of alveolar bone supporting partial-denture abutment teeth.

This study uses the intraoral microdensitometric method to examine the impact of masticatory pressure on the alveolar bone around the abutment teeth clasp. Two retroalveolar radiographs were carried out on all 30 subjects over a period of 3 months using a copper calibration stepwedge. The dental radiographs were digitized and converted into positive. Grey level values on dental radiographs in the alveolar bone area in 7 region of interest (ROI) were measured. They were converted into the equivalent thickness of the calibration stepwedge using mathematical methods and the difference of the bone density between the two radiographs was calculated. The results demonstrated that there were no statistically significant differences between the 1st and 2nd radiographs in any of ROI (p > 0.05).

A method to evaluate and compare two different intraoral radiographs of the same patient.

Objective of this study was to determine the accuracy of the method of the clinical intraoral densitometry, to compare differences in the calculation with or without subtraction of the background adjacent soft-tissues from the stepwedge (SW) and to verify which regression model best fitted the experimental data in order to express the measured values in equivalents of SW thickness. Two intraoral radiographs, one after another, were made for each of 6 patients. A copper SW (6 steps, thickness 0.05-0.3 mm) was attached to each radiograph, trying to avoid the superimposition of the bony structures. Films were processed and digitized. Grey levels were measured on each step of the SW, on the background of the SW and on the same 3 randomly chosen regions of interest (ROIs) on each digitized image. The measurement with and without the subtraction of optical densities of the background around the SW from the optical densities of the SW was performed. For the calculation of the SW thickness equivalents, the regression analysis was performed by using different regression models. The best fitting regression model was the 3rd degree polynomial. The results were more precise when using the subtraction of the background overlapping the SW.