Global co-occurrence of bruxism and temporomandibular disorders: A meta-regression analysis.

Background: Bruxism and temporomandibular disorders (TMD) are closely related, yet the relationship between bruxism and TMD remains one of the most debated topics in the literature.

Objectives: The aim of the study was to estimate the overall proportions of the co-occurrence of bruxism and TMD, and the prevalence of TMD in individuals with bruxism by continent. Additionally, factors that have an influence on these proportions, including geographical region, sex and other demographic variables, were analyzed.

Material and methods: A synthesis of data from 6 meta-analyses and systematic reviews published up to October 2024 was conducted. The data was extracted from 30 studies that analyzed 31 populations, with a total of 37,680 participants, of whom 5,117 were diagnosed with both bruxism and TMD. The analyses were conducted using the R statistical language.

Results: The global co-occurrence of bruxism and TMD was 17%, with significant differences observed between continents. In North America, the co-occurrence of these 2 conditions was 70%, followed by 24% in South America, 14% in Europe and 9% in Asia. The analysis revealed that the sex of the participants was a significant factor, as higher proportions of female participants in a study sample increased the likelihood of the co-occurrence of TMD and bruxism. The mean prevalence of TMD among patients with bruxism was 63.5%, with the highest rate observed in North America (98.3%) and the lowest in Asia (53.9%).

Conclusions: The meta-analysis underscores the high prevalence of TMD in individuals with bruxism, highlighting significant geographical variations in the co-occurrence of these conditions. A 1% increase in the proportion of female participants in a study group was associated with a 4.4% rise in the probability of the co-occurrence of TMD and bruxism. These findings suggest that temporal factors and the average age of participants did not significantly contribute to observed variability across studies. The results underscore the importance of geographical and demographic factors in understanding the interplay between bruxism and TMD.