Relationship between the Volume of Masticatory Muscle and Volume of the Mandibular Region Corresponding to the Denture Base in Japanese Edentulous Mandible

The volume of masticatory muscle and volume of the mandibular region corresponding to the denture base (V. M. D. B.) of edentulous Japanese cadavers were measured using Spiral X-ray CT to assess the correlation between masticatory muscles and V. M. D. B.. For the results, the average volume was the highest for the masseter (15.06 ± 7.12 cm3, n=32, followed by the medial pterygoid (6.72 ±2.94 cm3, n=32 and lateral pterygoid (5.74 ±2.76 cm3, n=32. The average volume of the mandible of the male cadavers was 52.69 ±10.01 cm3 (n=18), and that of female cadavers was 36.11 ±6.22 cm3 (n=14). The average volume of the V. M. D. B. of male cadavers was 6.58 ±2.79 cm3 (n=18), and that of female cadavers was 3.51 ±1.36 cm3 (n=14). The relationship of the masticatory muscles with the volume of the mandible and V. M. D. B. was assessed statistically, and the results showed that the volume of the mandible and V. M. D. B. correlated with the volumes of the medial and lateral pterygoids, but not with the volume of the masseter. The results suggest that various factors may be involved in the relationship between muscle and mandible volumes, and poor denture fit or misuse may play a major role. And if prosthetical factors play a major role in anatomical structure, the volumes of the medial and lateral pterygoids are unlikely to be affected by the use of dentures, but the volume of the masseter can be affected by denture use.