The population	(P)	Patients undergoing orthognathic surgical procedures for the correction of dentofacial deformities.
The intervention	(I)	Preoperative or postoperative administration of botulinum toxin type A (BoNT-A) as an adjunct to orthognathic surgery
The control	(C)	Conventional orthognathic surgical treatment without adjunctive administration of botulinum toxin type A (BoNT-A).
The outcomes	(O)	Clinical outcomes related to mechanical stability, skeletal stability/relapse, and postoperative recovery. Mechanical stability was defined as fixation-related integrity or complications (e.g., plate fracture), whereas skeletal stability referred to maintenance of the surgically achieved skeletal position over time; skeletal relapse was defined as postoperative change toward the preoperative skeletal position.