Objective To explore the indication, advantage and disadvantage of modified or classical technique of intraoral sagittal split ramus osteotomy (SSRO) for correction of mandibular prognathism. Methods From January 1997 to January 2005, 95 patients suffering from mandibular prognathism or accompanied by other deformities were treated with modified or classical technique of intraoral SSRO. Of 95 cases, there were 34 males and 61 females, aging 15 to 44 years, including 53 cases of single mandibular prognathism, 28 cases accompanied with mandibular deviation, 11 cases accompanied with maxillaryretrognathism, 2 cases accompanied with glossacele and 1 case accompanied with malar protrution. X-ray cephalometry showed: sella-nasion-A point(SNA) 80-83°, sella-nasion-B point(SNB) 80-84°, A point-nasion-B point(ANB)-3-1°.Fortythree cases were corrected by modified SSRO and 52 cases by classical SSRO. Results The face appearance and dental articulation of all the patients were improved greatly. In patients by classical SSRO, disorder of local sensibility occurred in 9 cases, mandibular fracture during the cleavage ofthe ascending ramus in 1 case, significant bleeding in 1 case, postoperative infection in 1 case and postoperative relapse in 3 cases. In patients by modifiedSSRO, disorder of local sensibility occurred in 2 cases and postoperative relapse in 1 case; no mandibular fracture, significant bleeding, postoperative infection and other complications occurred. With a follow-up of 3 months to 7 years, X-ray cephalometry showed SNA 81-83°, SNB 78-81°and ANB 1-4°. 〖WTHZ〗Conclusion Modified SSRO is an ideal method of correcting mandibular prognathism, especially severer mandibularprognathism accompanied by mandible deviation deformity.
ObjectiveTo establish a method to prefabricate titanium plate with three-dimensional (3-D) printing technique for correction of mandibular prognathism in sagittal splint ramous osteotomy (SSRO). MethodsBetween January 2012 and May 2013, 12 patients with mandibular prognathism (Angle III malocclusion) were treated. Among them, 9 cases were male and 3 cases were female. Their ages ranged from 19 to 35 years (mean, 25.6 years). With the 3-D facial CT data of these patients, 3-D printer was used to print the models for preoperational simulation. SSRO was performed on 3-D models, and the titanium plates were prefabricated on the models after the distal segments were moved backward and rotated according to occlusal splint. During operations, the proximal segments were fixed to distal segments by the prefabricated titanium plates. 3-D CT scans were taken to examine the temporomandibular joint position changes before operation and at 6 months after operation. ResultsThe skull models were manufactured by 3-D printing technique, and the titanium plates were reshaped on the basis of them. Twenty-four prefabricated titanium plates were placed during operations, and they all matched with the bone segments well. Evaluation of 3-D CT scans showed that the temporomandibular joint position had no change. All patients were followed up 7-12 months (mean, 10.6 months). The face type and dental articulation were improved greatly. All cases obtained satisfactory opening function and occlusion. ConclusionWith the titanium plate fabricated based on 3-D models, surgeons are able to improve or refine surgical planning so that the operation can be performed according to preoperative simulation precisely and the complications, such as dislocation of temporomandibular joint, can be prevented.