Aim: The aim was to compare the efficiency of mastication and maximum bite force of patients using two-implant overdentures with equator or locator attachments.
Subjects and methods: Twelve edentulous patients were recruited in the study. The patients were provided with new complete dentures and wore them for three months (CD, control group). Then two implants were installed bilaterally at the mandibular canine areas. Patients received overdentures that were attached to the implants with either equator (EOD) or locator attachments (LOD) randomly in a crossover design. The mixing ability test was used to assess chewing efficiency. The hue variation of mixed two different colored chewing gums was determined after five, ten, twenty, thirty, and fifty masticatory strokes. A digital bite force transducer was used to determine the maximum bite force. Both chewing efficiency and bite force were assessed after wearing CD, EOD, and LOD prostheses.
Results: Comparison between groups revealed a statistically significant difference (p <0.0001) in hue deviation across groups for each masticatory stroke. The values for deviation in CD were the highest, followed by the EOD values. The values for deviation in LOD group were the lowest. There were statistically significant differences (p <0.0001) in the mean values of maximum bite force between the groups. The greatest maximum biting force was found with LOD, followed by EOD, while the lowest biting force was found with CD. Regardless of attachment type, overdentures (EOD, LOD) had considerably greater maximum biting forces than complete dentures.
Conclusion: Within the limits of this study, it was concluded that overdentures retained with locator attachments have higher masticatory efficiency and maximum biting force than overdentures retained with equator attachments.