Comparison of the effects of occlusal splint and Botox injections on the amount of mouth opening and chronic pain in individuals with temporomandibular disorders: a systematic review and meta-analysis.

[OBJECTIVE] This systematic review and meta-analysis study was carried out to compare the effectiveness of occlusal splint (OS) and Botox (BTX) injections in temporomandibular disorders (TMDs).

[MATERIAL AND METHODS] Irrespective of the starting year, studies were searched for up to 2024 using PubMed, Web of Science, Scopus databases and the Google Scholar search engine. In the study, graded chronic pain scale and maximum mouth opening amount parameters were analysed with Comprehensive Meta-Analysis programme.

[RESULTS] Out of 619 studies, only six were included in the meta-analysis. The effect size was 0.293 in favour of BTX in the studies evaluating the maximum mouth-opening (MMO) range. However, the amount of MMO did not show a statistically significant difference between the OS and BTX groups (95% CI - 0.383 to 0.969, P = 0.395, z = -0.850). In the subgroup analyses carried out based on the follow-up periods, it was found that the MMO was statistically significantly higher in the BTX group at the first week and in the OS group at the third month. However, there was no significant difference observed at the first, second, sixth and twelfth month follow-ups (P > 0.05). No significant difference was found between the groups (P > 0.05) in the publications that evaluated the graded chronic pain scale (GCPS), although an effect size of 0.673 was found in favour of OS (95% CI 0.331 to 1.365, P = 0.272, z = -1.098).

[CONCLUSION] BTX injections and OS applications show significant differences in the MMO of individuals in the early period. In contrast, the MMO of individuals and the GCPS show similar findings in the sixth month and longer follow-up.