Clinical Effectiveness of IncobotulinumtoxinA Using a Standardized Protocol in the Management of Myogenous Temporomandibular Disorders: A 12-Month Retrospective Study

Background: Myogenous temporomandibular disorders (TMDs) are a common subtype of orofacial pain. Evidence regarding treatment with botulinum toxin type A (BoNT-A) remains heterogeneous, and its use is generally limited to refractory cases. This study evaluated 12-month clinical outcomes following an incobotulinumtoxinA protocol (the Ângelo Botulinum Toxin Protocol®) in adults with DC/TMD-confirmed myogenous TMD unresponsive to conservative therapy. Methods: This retrospective observational study reviewed records from 98 adults treated with incobotulinumtoxinA following the predefined injection protocol. All patients had failed ≥ 3 months of conservative management and completed ≥ 12 months of follow-up. Outcomes included myalgia severity (0–3), patient-reported orofacial pain intensity (VAS 0–10), and maximum mouth opening (MMO). Favorable outcome criteria required myalgia 0–1 or VAS ≤ 2 and MMO ≥ 35 mm. Results: Myalgia significantly decreased at 12 months (2.69 ± 0.64 to 0.43 ± 0.85; p < 0.001). Patient-reported orofacial pain intensity also improved (2.44 ± 2.54 to 0.37 ± 1.33; p < 0.001). MMO remained stable, indicating preserved mandibular mobility. Overall, 79.6% of patients met the predefined favorable outcome criteria. Reintervention was required in 12 patients; 7 received additional incobotulinumtoxinA injections, and 5 underwent TMJ arthrocentesis. No complications were observed. Conclusion: This protocol was associated with improvements in muscular pain and orofacial discomfort while preserving mandibular mobility. However, given the retrospective design and absence of a control group, these findings should be interpreted as hypothesis generating.