Studies of biologic parameters for denture design. Part III: Effects of occlusal adjustment, base retention, and fit on masseter muscle activity and masticatory performance.

EMG recordings of ipsilateral and contralateral masseter muscles and standardized masticatory performance tests were made in 20 denture wearers before and after modifications were made to their clinically unsatisfactory dentures. The improvement of retention and stability by correction of gross occlusal prematurities and by the use of a denture adhesive or base reline with a soft tissue-conditioning material did not significantly alter the chewing performance or muscle activity during mastication in denture wearers. The results support our previous findings that the influence of denture factors on chewing ability of denture wearers is limited. To avoid variations in EMG activity caused by changes in electrode positions, all tests for a given subject were made at the same sitting. Thus the study design did not provide time to denture wearers for their neuromuscular mechanism to adapt to the modifications prior to testing masticatory function. A replication of this study that permits sufficient adaptation time after each modification is suggested to validate the findings.