Article ID: JPR_D_24_00318
Purpose: Jaw movements in sleep bruxism (SB) presumably play a functional role in salivary stimulation and oral tissue protection. This study aimed to investigate the relationships between SB, oral wetness, and salivary flow.
Methods: Participants underwent polysomnography in a sleep laboratory, during which rhythmic masticatory muscle activity (RMMA) and swallowing were recorded. The degree of oral moisture was measured before sleep, during sleep, and upon waking. The unstimulated salivary flow rate (USFR) and stimulated salivary flow rate (SSFR) were measured before sleep and upon waking. Correlations between the RMMA index, degree of oral moisture, and salivary flow were examined.
Results: Seventeen participants (10 males, 7 females, 28.2 ± 8.6 years old) were included. The degree of oral moisture and USFR were not significantly correlated with the RMMA index. The SSFR before sleep demonstrated a significant moderately negative correlation with the RMMA index (ρ = -0.637). The frequency of RMMA that occurred with swallowing per hour demonstrated a significant negative correlation with the SSFR before sleep and upon waking (ρ = -0.703, -0.527, respectively). Swallowing occurred significantly more frequently in the last one-third of the RMMA episodes, and the frequency of phasic and mixed types of RMMA that occurred with swallowing demonstrated a significant negative correlation with the SSFR before sleep (ρ = -0.583, -0.511, respectively).
Conclusions: These results suggest a relationship between SB and the ability to secrete stimulated saliva. SB may have a functional role in stimulating saliva secretion, and an increase in SSFR may alleviate SB.
