Impact of chewing muscle anesthesia on masticatory performance in healthy participants

The impact of the muscle spindles in the masticatory performance remains elucidated. This study aimed to investigate the impact of local anesthesia in the jaw-closing muscles on masticatory performance in healthy participants. Thirty healthy pain-free volunteers underwent in two rounds of chewing tasks involving two types of viscoelastic candies and a two-coloured chewing gum. Lidocaine (3.0 mL) was injected into a total of six points in the masseter and temporalis muscles bilaterally for the second round. Pain intensity, fatigue, the number and area of particles, and the degree of mixing of the chewing gum were assessed at baseline and after each round of chewing. The number of candy particles after injection of lidocaine, was significantly lower (33%) for women compared to the results without anesthesia (p < 0.05). There was no significant difference in the variance of hue of the two-coloured chewing-gum when comparing values before and after anesthesia. None of the participants experienced any pain during the experiment. However, self-reported fatigue increased during the second round, i.e., after anesthesia, with significantly higher values observed at the final assessment point. (p = 0.029). Local anesthesia of the jaw-closing muscles appears to impair the masticatory function in women, leading to reduced efficiency in food comminution compared to normal mastication. The observed sex differences suggest that women may be more vulnerable to neuromuscular control alterations following sensory alterations.