engleski

The influence of dental status on masticatory muscles activity in elderly patients

Abstract Aims. The objective of this study was to determine whether the elevator and depressor muscle activity during five minutes mastication is affected by the presence of the prosthetic appliance in eld erly patients. Methods. Thirty edentulous subjects (EG) and 30 age-matched dentate subjects (DG) were studied. Surface electromyographic (EMG) recordings were obtained from the anterior temporal muscle (T), masseter muscle (M) and from the submandibular group in the region of the anterior belly of the digastrics muscle (D) on the left (L) and right (R) side. Muscle activity was registrated during maximal voluntary contraction (MVC) at the intercuspal position, maximal opening (Omax), and during five minutes of mastication. Elevator muscle activity during mastication was expressed in percentages of the maximal muscle activity in intercuspal position and depressor muscle activity was expressed in percentages of maximum opening. By using mixed ANOVA design, the effect of three factors was investigated: the factor of muscle with six muscles involved, the factor of time (five minutes of mastication), and the factor of dental status where some participants had their own natural dentition whereas others had complete dentures. Results. The results revealed significant effects of factors muscle and time (pP<0.001 for factor "muscle" pP<0.001 for factor "time"). The muscle was not significant by group interaction (p=0, 254), whileThe time by group interaction was significant (pP=0, .046). In EG muscle activity gradually decreased during the whole five minute interval of mastication, while in DG it decreased more rapidly from the 1st to the 3rd minute and then it increased till the 5th minute. There was also a significant effect regarding the presence of natural teeth or complete dentures (pP<0.034). Complete denture wearers had higher muscle activity relatively to % of MVC or % of Omax than dentate subjects. Conclusions. Muscle activity during five minutes of mastication depends greatly of the presence of the prosthetic appliance, since edentulous subjects had to use higher potentials of muscle activity (% of MVC or % of Omax) than age matched dentate subjects and were unable to increase activity at the end of mastication. The difference in chewing patterns and activity between complete denture wearers and dentate subjects should be explained to the patients prior to the prosthetic treatment in order to put their expectations into right perspective.

electromyography; masticatory muscles; mastication

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