Abstract
Fifty-four Donryu male rats were divided into three groups, the control group, the soft diet group (fed with powder diet containing the same components as solid one, from the 43rd week) and the molarless group (all molars were removed at 43 weeks and then fed with powder diet). At 47, 60 and 74 weeks, morphometries of mandibular bone by a handy microscope system and measurements of bone mineral density (BMD) by the image analyzing system were performed in addition to observations by light microscopy of the attachment of masseter muscle to mandible. The results obtained are as follows.
1. Occlusal-and masticatory alterations-related changes were observed in the attachment of the masseter muscle to mandible in addition to age-related changes.
2. The height of the mandibular ramus in the experimental groups were shorter than that of the control group, showing a statistical significance (p<0.01).
3. BMD at the attachment of the masseter muscle to mandible in experimental groups was less than that of control group in each weeks, showing a statistical significance (p<0.01).
4. BMD at the attachment of the masseter muscle to mandible in 60 and 74 weeks in experimental groups was less than that of the incisal alveolar bone, showing a statistical significance (p<0.05).
