The Effect of Prosthodontic Treatment on Mastication Predominance

Objectives: The purpose of this study was to investigate the effect of prosthodontic treatment for patients with unilateral missing posterior teeth in terms of mastication predominance using subjective and objective evaluation. The present study also examined differences in the effect of treatment with removable partial dentures (RPD group) and implant-supported fixed partial dentures (IMP group).
Methods: The subjects comprised 86 patients with missing posterior teeth on one side (41 RPD group, 45 IMP group). Subjects were asked to chew test foods (chewing gum, peanuts, beef jerky) freely. Electromyographic activity of the bilateral masseter muscles was recorded. The chewing side (right or left side) was judged by the level of root mean square electromyographic amplitude. Mastication predominance was assessed using the mastication predominance score (MPS; range minus 100-100%) and the mastication predominance index (MPI; range 0-100%). The self-awareness of the mastication predominance (SAMP) was evaluated using a modified visual analog scale.
Results: There were significant differences in MPS and MPI between pre- and post-treatment evaluations for both groups (P<0.01, Mann-Whitney test). The amount of change in the MPI was significantly different between the RPD group and the IMP group for all three test foods (P<0.01, Wilcoxon test). The MPS was strongly correlated to the SAMP in the both group. There were no significant differences in the SAMP between pre- and post-treatment evaluations for both groups (P>0.05, Mann-Whitney test).
Conclusions: Prosthodontic treatment improved mastication predominance in patients with unilateral missing posterior teeth. Implant-supported fixed partial dentures are more effective than conventional removable partial dentures in terms of improving mastication predominance. It was suggested that the objective evaluation of mastication predominance could be more accurate than the subjective methods.