Studies of biologic parameters for denture design. Part II: Comparison of masseter muscle activity, masticatory performance, and salivary secretion rates between denture and natural dentition groups

Bilateral masseter muscle activities exerted during masticatory and salivary secretion rate tests of a group of 18 denture wearers were compared with a group of eight persons with 26 or more natural teeth. Denture wearers applied 22% to 39% of the muscle force applied by the ND group to chew peanuts or carrots and showed markedly lower masticatory performances. The average muscle activity was higher for chewing peanuts than carrots in the ND group but was similar for both test foods in the AD group. Motor discrimination seems to be intact in denture wearers, but their inability to tolerate high masticatory pressures may prevent them from exerting discriminatory forces comparable to those applied by persons with natural dentition when chewing relatively tough foods of varying hardness. The results indicate that the reduced muscle force applied by denture wearers is another important factor that contributes to their diminished chewing ability. Even though the denture wearers were older and applied less muscle activity during chewing, they produced slightly higher rates of stimulated parotid saliva than the ND group. This supports our previous findings and further indicates that the mucosal stimulation of dentures compensates for decreased muscle activity and absence of periodontal receptor stimulation for producing saliva in healthy denture wearers.