Chewing performance of TMD vs. Controls: A new experimental model

Objectives: Limitations in masticatory function are a common complaint by patients with TMD. However, published data, relying mostly on a classic sieve method for assessing particle size, suggest equivalent chewing performance by TMD patients and healthy controls. This study focused on developing a new measurement approach using optical scanning and then testing its utility.

Methods: In Phase I, standard objects of various sizes, shapes, and number were used to develop a valid scanning protocol. For Phases II & III, each sample was based on 2 grams of OptosilŪ chewed at the rate of one cycle/second for forty seconds, expectorated, rinsed, dried, spread on a flat bed scanner, and scanned. In Phase II, methods reliability was assessed using the ICC statistic for the parameters count, median, upper and lower quartile, and minimum and maximum values. In Phase III, two trials of chewed samples were obtained from 20 asymptomatic controls and 25 TMD patients in order to assess subject reliability and overall utility. Standard scanner software, Image J, and Stata were used for analysis.

Results: Phase I resulted in a valid protocol for count and size estimation of known samples. In Phase II, scanning method reliability for 5 of 6 parameters exceeded ICC of 0.95. In Phase III, the best subject reliability for the two trials was 0.6 among the 6 parameters. Using the statistics from trial 2, the comparison between subject groups was assessed with individual t-tests, and the TMD group exhibited worse performance (p<0.05) for 5 of the 6 measurement parameters.

Conclusions: The optical measurement method is valid and reliable for 5 of 6 parameters with respect to chewed Optosil particles. These results demonstrate that individuals with TMD chew less well compared to controls.

This research was supported by NIDCR Grant U01-DE013331 and the Arnold Stern Fund for Student Research.