Influence of botulinum toxin A in pain perception and condyle-fossa relationship after the management of temporomandibular dysfunction: a randomized controlled clinical trial.

[OBJECTIVES] To investigate the pain perception (PP) and condyle-fossa relationship (CFR) after botulinum toxin A (BoNTA) injection in the masseter muscles of painful muscular temporomandibular dysfunction (TMD) patients.

[MATERIALS AND METHODS] Fourteen women (aged 29.7 ± 5.4 years) diagnosed with myogenic TMD were randomized in the BoNTA-treated group (TG) and control group (CG). TG masseter muscles (n = 7) were bilaterally injected with 30 U. The CG (n = 7) were injected with saline injections. Condyle-fossa relationship (CFR) spaces were measured in sagittal (SP) and frontal planes (FP) of images of cone-beam computed tomography (CBCT) done before (T) and after 30 days' interventions (T). Visual analogue scale (VAS) measured the patients' TMD pain perception (PP). Data were compared by generalized linear models considering the results over time (α = .05).

[RESULTS] There were no statistical differences in CFR in the SP or FP for TG and CG over time (p ˃ .05), except for frontal lateral space CFR (p < .05). In both groups, the condyle was positioned medially after interventions. Frontal lateral space increased in TG for both, left and right sides, over time (p < .05), as well as PP decreased over time (p < .05) for TG and CG.

[CONCLUSIONS] The results depicted that there was no significant association with BoNTA injection in TMD masseter muscles in PP and CFR, except considering the frontal lateral space of CFR.

[CLINICAL RELEVANCE] BoNTA injection in the masseter muscles may not promote clinically significant shifts in the condyle-fossa relationships of muscular TMD patients.