Effects of occlusal contact loss on the preferred chewing side on masticatory function: An experimental randomized crossover trial.

PURPOSE: This study aimed to investigate the effects of simulated molar loss on masticatory function, with a focus on the preferred chewing side (PCS).

METHODS

Twenty-eight participants with intact dentition were enrolled. Experimental occlusal splints (OSs) were fabricated to simulate a unilateral shortened dental arch in which the molars on one side did not contact the opposing teeth. Participants were randomly assigned to two groups. In the first group, OSs with the molar region removed on the PCS (PCS removal) were tested first, followed by repaired OSs with the molar region removed on the non-PCS (non-PCS removal). The second group underwent the reverse sequence. Outcome measures included maximum occlusal force (MOF), masticatory efficiency (ME), and subjective masticatory ability (SMA) (α=0.05).

RESULTS

No significant difference in full-arch MOF was observed between the conditions. However, the second premolar on the removal side exhibited a significantly higher MOF after PCS removal, whereas ME and SMA significantly decreased after PCS removal (P < 0.05). Moreover, the reduction in full-arch MOF following PCS removal was significantly smaller in participants whose main occluding area (MOA) was located at the second premolar compared with those with the MOA at the first molar (P < 0.05).

CONCLUSIONS

Loss of molar occlusal contact on the PCS impairs both objective and subjective masticatory function and increases the occlusal load on the second premolar. These findings suggest that molar loss on the PCS may necessitate prosthetic intervention, whereas the impact may be attenuated in individuals whose MOA is located more anteriorly.