Influence of overhanging posterior tooth restorations on alveolar bone height in adults.

The aim of this radiographic investigation was to compare the approximal bone height adjacent to class II amalgam restorations with and without overhangs to the bone height adjacent to homologue intact tooth surfaces, and to determine the possible effect of age and sex on the relative amount of such bone resorption. The x-rays of 43 persons aged 27--45 years and 42 persons aged 46--64 years were examined. In the total material the average amount of bone loss increased with age and was 0.34 mm greater in men than in women. About 50% of all posterior tooth restorations had an overhang. A comparison between the mean heights of approximal bone adjacent to sufaces with an overhang and homologue intact surfaces showed a statistically significant difference. When equal comparisons were made separately in the younger and the older age groups, only the older group showed a similar difference at a statistically almost significant level. The effect of overhanging restorations thus seemed to be accentuated with age. When men and women were studied separately, only men showed statistically significant differences between the age groups. The investigation confirms earlier results that overhanging posterior restorations are associated with excessive marginal approximal bone loss.