Influence of alveolar support on stress in periodontal structures.

The influence of alveolar bone support on the functional capability of a tooth remains unclear. It was hypothesized that a reduction in alveolar support causes an increase of maximum stress in the periodontal structures. Mathematical models of the maxillary incisor to simulate in vivo tooth movement were constructed with periodontium of normal or reduced bone height, and normal or widened periodontal ligament (PDL) space. Under simulated bite force, the maximum tensile stress at the lingual cervical region in the PDL increased with bone height reduction, but decreased with PDL widening. The compressive stress at the cervical region in the cortical bone was no more than 22% of the yield strength of bone, and did not increase by the height reduction with widened PDL. The result suggests that the height reduction potentially causes mechanical damage to the PDL, but, of itself, is not likely to have a negative effect on the bone.