Orthognathic surgery is a surgical procedure involving one or both jaws to correct skeletal discrepancies, restore proper occlusion, and improve facial aesthetics. Individuals with dentofacial abnormalities often experience difficulties with chewing, biting, and social interaction, which may negatively impact psychological well-being and overall quality of life. Orthognathic surgery must be combined with orthodontic treatment before and after the operation to ensure optimal functional and aesthetic outcomes. The conventional "orthodontics-first" approach involves prolonged preoperative orthodontic treatment (typically 12-24 months, sometimes up to 48 months) to decompensate dental alignment and reveal the true skeletal discrepancy prior to surgery. Although effective for achieving stable occlusion, this method is time-consuming and may temporarily worsen facial aesthetics and function during the preoperative phase. The "surgery-first" approach eliminates or significantly reduces preoperative orthodontics, performing surgery first followed by postoperative orthodontic treatment. This method shortens overall treatment time, provides immediate aesthetic improvement, facilitates favorable orthodontic tooth movement, and may lead to earlier improvement in conditions such as obstructive sleep apnea. It is generally recommended for patients with mild anterior crowding, minimal transverse discrepancies, a flat or mild curve of Spee, and normally inclined incisors. Common surgical techniques include genioplasty, bilateral sagittal split osteotomy (BSSO), oblique ramus osteotomy, and Le Fort I osteotomy. Whenever possible, procedures are performed intraorally to avoid visible scarring. Orthognathic surgery induces not only anatomical and functional changes but also psychological adaptations. Soft tissues, masticatory muscles, and the temporomandibular joint (TMJ) adapt to new skeletal relationships, contributing to improved facial balance and patient self-perception. However, there is currently no unified diagnostic algorithm to comprehensively evaluate postoperative anatomical, physiological, and socio-emotional changes. Emotional satisfaction, TMJ structural changes, muscle strength variations, sleep quality, and pain outcomes remain insufficiently studied. The study proposes two hypotheses: the null hypothesis (H0) assumes no postoperative changes in TMJ anatomy, masticatory muscle strength, emotional response, facial pain, sleep quality, or depressive characteristics; the alternative hypothesis (H1) assumes that such changes do occur. The objectives are to evaluate masticatory muscle strength and structure, TMJ anatomical changes, emotional state, depression and anxiety predisposition, sleep quality, facial pain, and aesthetic perception before and after surgery. The study will include up to 100 patients undergoing bimaxillary orthognathic surgery (with or without genioplasty) at the Lithuanian University of Health Sciences Kaunas Clinics. Assessments will be conducted preoperatively, immediately postoperatively, and 3-6 months after surgery. Methods include CBCT imaging for TMJ evaluation, electromyography for masseter muscle strength, emotional analysis using the iMotions platform (facial expression analysis and electrodermal activity), and validated questionnaires (PHQ-15, HADS, VAS). Strict ethical standards will be followed in accordance with international guidelines, with informed consent obtained from all participants. No additional financial costs or conflicts of interest are declared. The expected outcome is to determine correlations between anatomical, functional, psychological, and aesthetic changes following orthognathic surgery, providing a more comprehensive understanding of patient satisfaction and overall quality-of-life improvement.
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Change in Temporomandibular Joint (TMJ) Anatomical Structures After Orthognathic Surgery
Timeframe: Baseline (1 day before surgery) and 3-6 months after surgery