Reliable measurement of incisal bite force for understanding the control of masticatory muscles

Reliable measurement of incisal bite force for understanding the control of masticatory muscles:

Publication date: Available online 20 February 2020

Source: Archives of Oral Biology

Author(s): Luciana S. Moreira, Leonardo A. Elias, Carina M. Germer, Evanisi T. Palomari

Abstract

Objective

In the present study, we aimed at evaluating the steadiness of incisal bite force during isometric contractions of masticatory muscles.

Design

Two separate experiments were carried out in 11 healthy young women. A first experiment was performed to test the reliability of our protocol for measurement of incisal bite force steadiness. The second experiment aimed to evaluate the steadiness of incisal bite force at four submaximal (i.e., percentage of maximum voluntary contraction, MVC) levels (5%MVC, 10%MVC, 15%MVC, and 20%MVC), along with the bilateral myoelectric activity of two masticatory muscles (temporalis and masseter).

Results

The results from the first experiment showed that our protocol is substantially reliable (intraclass correlation coefficient, ICC > 0.80) for estimating force variability and moderate reliable (0.60 < ICC < 0.80) for estimating spectral properties of force signals. In the second experiment, we found that force standard deviation (SD) increased proportionally to the power of mean force, and coefficient of variation (CoV) was higher at low-intensity contractions and maintained at an approximately constant level for high-intensity contractions. The force-EMG relationships were linear for both muscles at the contraction intensities evaluated in the study (5%-20%MVC), and the median frequency did not change with contraction intensity.

Conclusion

Therefore, we presented a reliable method to estimate the incisal bite force, along with additional data on force control and myoelectric activity of jaw elevator muscles during isometric steady contractions.