Dentures Used for Rehabilitation of Mastication After Loss of Teeth Maintain Proper Biomechanical Properties of Masseter Muscles—A Comparative Study

<b>Background</b>: Various types of dentures are applied in the treatment of missing teeth. The research carried out so far has proven that both the absence of teeth and the replacement of missing teeth with dentures affect the functional condition of masseter muscles. The purpose is, thus, to find out how the tone, elasticity, and stiffness of masseter muscles change after prosthetic treatment. <b>Material and methods</b>: The material for the study consisted of 137 individuals, who were divided into group 1, with dentures (n = 87) and undergoing prosthetic treatment, and group 2, without dentures (n = 50) with teeth preserved, and not undergoing prosthetic treatment. Additionally, group 1 was divided into subgroups, in accordance with the type of prosthetic treatment applied: group 1a-removable complete dentures (n = 14), group 1b-removable partial dentures (n = 48), group 1c-fixed partial dentures (n = 22), group 1d-fixed complete dentures (n = 3). The biomechanical properties of masseter muscles, namely: tone, stiffness, and elasticity were assessed by means of myotonometry. The measurements were taken under muscle relaxation and under maximum muscle contraction. <b>Results</b>: The values of the parameters of tone, stiffness, and elasticity were higher in group 2, without dentures, in comparison with group 1, with dentures, yet they did not differ with statistical significance. The type of prosthesis used affected the results obtained. Masseter muscles demonstrated the best biomechanical parameters in the case of applying fixed partial dentures. <b>Conclusions</b>: Prosthetic replacement of missing teeth contributes to maintaining the good condition of masseter muscles, which has been confirmed by the results of myotonometric measurements taken.