Statement of problem: Determining the preferred chewing side may be an important factor in prosthetic treatment planning, especially where additional support for a removable dental prosthesis can be provided by implants.

Purpose: The purpose of this clinical study was to investigate the validity and reproducibility of 3 different tests to determine the preferred chewing side.

Material and methods: A total of 82 partial denture wearers, with an average age of 70 years, were enrolled in this study. The first test (CG) evaluated the left or right position of a piece of chewing gum after spontaneous mouth opening during mastication. A second test (ASI) videotaped 30 seconds of mastication and analyzed the distribution of masticatory cycles by means of an asymmetry index. For the third test (VAS), participants were asked to mark their subjective perception of their preferred chewing side on a visual analog scale representing the right and left sides. All the tests were performed and repeated in a randomized sequence. The reproducibility of the tests was first evaluated. The mean values of the ASI and VAS tests were calculated, and the results were compared with the second series of the CG test. The Pearson correlation test was used to associate ASI and VAS, and the Cohen kappa agreement was used for the inter-reliability of CG (α=.01).

Results: The results indicated fair to almost perfect reproducibility for the 3 tests. Kappa values were.37 (P<.01) for the CG,.47 (P<.01) for the ASI and.91 (P<.01) for the VAS. Correlation coefficients resulted in rho=.86 (P<.01) for the ASI and rho=.97 (P<.01) for the VAS. The correlation between ASI and VAS was excellent, with rho=.85 (P<.010). CG and ASI (test kappa=.36, P<.010) and CG and VAS (test kappa=.39, P<.010) showed fair agreement.

Conclusions: ASI and VAS seem more reliable than CG to determine a patient's preferred chewing side and might be helpful within the context of prosthetic treatment planning, where additional support may improve denture function.