Analysis of oral microbiota changes in patients with bruxism based on high-throughput sequencing

Objective To evaluate the clinical efficacy of rigid and soft orthodontic pads in treating nocturnal bruxism in adolescents, and to investigate changes in oral microbiota before and after treatment through high-throughput sequencing of patient oral saliva. Methods A total of 56 patients with nocturnal bruxism were randomly assigned to receive either rigid or soft pads for treatment, with 28 cases receiving rigid pads and 28 cases receiving soft pads. Patients wore the pads for more than 10 hours during sleep daily and returned for follow-up visits at 3, 6, and 9 months post-treatment. High-throughput sequencing was performed to analyze saliva samples collected from healthy volunteers, pre-treatment subjects, and selected patients at 9 months post-treatment. Results At 9 months post-treatment, the treatment efficacy rates for soft and rigid pads were 92.86% and 71.43%, respectively (P=0.036, χ²=4.382). The overall satisfaction rate with rigid pads at 9 months was 71.43%, significantly lower than that with soft pads (96.43%), with a statistically significant difference (P=0.01, χ²=6.486). The analysis of oral microbiota revealed a significant reduction in microbial richness before treatment in patients (P<0.05). According to the Shannon and Simpson indices, the microbial diversity of patients before treatment was lower than that of the control group (P=0.058), with some improvement observed post-treatment. The overall community structure of the oral microbiota in bruxism patients underwent changes, with the soft pad group exhibiting more clustered communities compared to the control group. Compared to the control group, elevated expression levels of Neisseria, Streptococcus, Rhodobacter, and Veillonella genera dominated the sample clustering in bruxism patients, potentially correlating with processes such as CDP-diglyceride biosynthesis, the pentose phosphate pathway (non-oxidative branch), and de novo nucleotide synthesis pathway I. Conclusion This research explored the relationship between oral microbiome and sleep bruxism, which may elucidate potential mechanisms of the brain-mouth axis. Trial registration:The study was approved by The Medical Ethics Committee of Hefei Stomatological Hospital (registry:National Universal Health Security Information Platform, Medical Research Registration and Filing Information System, trial registration number:ChiCTR2600128478 ,data of registration:Comparative Analysis of Clinical Efficacy of Soft and Hard Splints in the Treatment of Bruxism and Clenching in Adolescents; The date of registration:2026.07.21).