Tooth and Bone-borne Cutting/Repositioning Guide and Patient-specific Implant(PSI)

Dentofacial deformity refers to a group of disorders characterized by malocclusion and facial asymmetry resulting from developmental abnormalities of the maxilla and mandible, which cause morphological and positional anomalies of the jaws. Compared with the traditional orthodontics-orthognathic surgery-orthodontics treatment protocol, the surgery-first approach has witnessed a continuous expansion of its clinical application scope. Nevertheless, academic controversies persist regarding its indication boundaries, postoperative jaw stability, and adaptive changes of the temporomandibular joint. In orthognathic surgery, computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guides indirectly determine the three-dimensional spatial positions of the maxilla and mandible through occlusal relationships. The tooth-bone dual-supported osteotomy and positioning guide combined with pre-bent patient-specific implants (PSIs) forms a novel surgical guide system that enables independent and direct positioning of the maxilla. Theoretically, this system can eliminate errors derived from mandibular positional instability and thereby improve surgical accuracy. However, comparative studies investigating the clinical application of these two types of guides in surgery-first orthognathic surgery are still lacking. This prospective, randomized, controlled, single-blind clinical study aimed to explore the clinical value of PSIs and conventional CAD/CAM guides in surgery-first orthognathic surgery, with primary outcomes focusing on surgical accuracy, postoperative jaw stability, and temporomandibular joint alterations. The findings will provide evidence-based medical support for the expanded application of this novel technique in precision orthognathic surgery.