Postoperative changes in mandibular position after mandibular setback surgery via the surgery-first approach in relation to the increase of vertical dimension and the amount of mandibular setback

Evaluation of Postoperative Mandibular Positional Changes After Mandibular Setback Surgery in a Surgery-First Approach: Isolated Mandibular Surgery Versus Bimaxillary Surgery

“…The SFA has become a treatment option for surgical and orthodontic treatment because of its clinical success in past decades; however, postoperative stability remains a concern for surgeons and orthodontists. 1,5,10,11,16,23 Although several studies have reported similar postoperative stability in the SFA and OFA, 21,24,25 some studies also have reported less stable results. 3,11,25 Kim et al 11 evaluated postoperative stability in 60 patients who underwent mandibular setback surgery using the OFA or SFA.…”

“…A geometric method was used to predict the mandibular forward movement resulting from the counterclockwise rotation that occurs during postoperative orthodontic treatment. 5 The VD increase from the occlusal interference in surgical occlusion was measured using 2 horizontal lines that were parallel to the maxillary occlusal plane. These were drawn on the dental casts of the maxilla and mandible in a preoperative occlusion.…”

“…Previous studies have discussed mandibular forward movement from counterclockwise rotation and have suggested that it is a contributing factor for greater postoperative mandibular forward movement in the SFA. 3,5 This inevitable mandibular forward movement in the SFA should be considered in the treatment planning and evaluation of the outcome. Adjustments in treatment planning might be necessary for better treatment outcomes.…”

“…Recently, orthognathic surgery without preoperative orthodontics, which is known as the surgeryfirst approach (SFA), has been performed to overcome the esthetic and functional drawbacks associated with long preoperative orthodontic treatment. 5,6 Without preoperative orthodontics, total treatment duration and patient discomfort can be considerably decreased, and postoperative tooth movement can be accelerated because of the regional acceleratory phenomenon (RAP). [7][8][9] In addition, patients are satisfied with the treatment because of the immediate improvement in facial profile, which can have a positive psychological impact on patients in the early stage of the treatment period.…”

“…As occlusal settling progresses during postoperative orthodontic treatment, the mandible exhibits counterclockwise rotation followed by mandibular forward movement. 3,5,15,16 Therefore, postoperative mandibular forward movement might be greater in the SFA than in the OFA, especially in cases with severe occlusal interferences in surgical occlusion. To achieve a successful outcome after an SFA, it is necessary to consider the mandibular forward movement from counterclockwise rotation and reflect this forward movement in the surgical plan.…”