BACKGROUND:Aclassical orthognathic schemefor mandibular prognathism includespreoperative cephalometric analysis,acquiring modulus, facebow transfer, modelsurgery, making occlusion plate.This process is cumbersome,complex,andproneto have bias. Moreover, orthognathic effects are difficult to be predicted, which is a majordifficultyindoctor-patientcommunication.
OBJECTIVE:To summarize and analyze the use of three-dimensional scanning techniques in the treatmentand diagnosisof mandibular prognathism, including principle, application and relative merits, thusprovidingreference forapplying to theclinic.
METHODS:Papers addressing the use of three-dimensional scanning techniques in thediagnosisand treatment of mandibular prognathism were retrieved by computer in Wanfang and PubMed databases with the key words of “three-dimensional scanning, class III,orthognathic, mandibular prognathism” in Chinese and English, respectively. A total of 48papers were included for review.
RESULTS AND CONCLUSION:Compared with the traditional technology,the three-dimensional scanning technology has high accuracy and efficiency in the diagnosis and treatment of mandibular prognathism, and candirectlycapture the 3D geometry of objects for modeling, colection and measurement of biological data, which provides a reliable monitoring method for postoperative assessment andfolow-up. Compared with the CT,thethree-dimensional scanning technology cannot show the internal structure and separate hard and soft tissues, which should be reasonably chosen according to practical data.

Chitosan-based microspheres use chitosan as the main material to obtain particles with special structures through microsphere processing technology. They have the ability of slow and controlled release of drugs and the role of scaffolding, which have great application prospect in stomatology, but the application of chitosan-based microspheres is still in the research stage and has not yet been applied in clinical practice. This article reviews progress of domestic and foreign research on chitosan-based microspheres, in aspects of treatment of oral and jawbone tissue defects, periodontal diseases, dental pulp diseases and nerve tissue injury, in order to provide reference for follow-up research.

Objective: To invesigate the therapeutic effect of anterior subapical osteotomy combined with postoperative orthodontic treatment for bimaxillary protrusion based on surgery-first approach(SFA). Methods: From April 2015 to April 2016, 22 adult patients with bimaxillary protrusion were treated with bimaxillary anterior subapical osteotomy without peroperative orthodontic treatment. Digital computer-aided technology was used for preoperative design and dental model simulation surgery. Then the occlusal guide plate was made for intraoperative built-up of temporary occlusion. Two weeks after orthognathic surgery, a short-term orthodontic treatment was carried out to improve the occlusion. Cephalometric analysis was done to evaluate the treatment effects. 19 cephalometric parameters about hard and soft tissues were measured and compared in all cases before and after SFA combined treatments. All data were statistically analyzed by SPSS software package. Results: Primary healing was achieved in all the 22 cases without any infection or necrosis of bone and dental pulp. During the follow-up period of 6-12 months, all the patients were satisfied with the profile contour. The cephalometric parameters of hard and soft tissues changed remarkably. U1E-McN and L1E-McN set back (-10.5±4.9) mm and (-8.0± 6.9) mm respectively. Upper and lower lip set back obviously. SNA decreased from (82.5±2.8) to (77.9±2.3) degrees on average. SNB decreased from (79.1±5.4) to (74.6±3.8) degrees on average. Upper and lower lip protrusion decreased obviously. TUL-E line decreased from the mean value of (2.7±2.7) mm to (0.5±3.2) mm and TLL-E line from (5.2±4.0) mm to (1.4±2.7) mm. The aesthetic contours were remarkably improved. Conclusions Anterior subapical osteotomy combined with postoperative orthodontic treatment based on SFA could correct adult bimaxillary protrusion effectively with normal occlusion, satisfactory soft tissue aesthetic profile.

Objective: The purpose of this study was to explore the surgery-first approach in sequential combined orthodontic-orthognathic treatment to shorten total treatment duration and improve the clinical outcome. Methods: This study included 185 patients with Angle classⅢ malocclusion. The patients were divided into 3 different types according to cephalometry analyses and facial features. ①Type Ⅰ: mandibular prognathism or asymmetry mandibular prognathism; ②Type Ⅱ: mandibular prognathism and maxillary retrusion; ③ Type Ⅲ: mild Angle′s Class Ⅲ malocclusion, cross bite in anterior teeth, or normal overlap and overbite relation with midfacial hypoplasia. All of patients received surgery first approach therapy. The surgical procedures were chosen according to different malformation types. Type Ⅰ was treated with the sagittal split ramus osteotomy (SSRO). Type Ⅱ was treated by Le Fort Ⅰmaxillary osteotomy combined with SSRO. Type Ⅲ underwent anterior subapical osteotomy combined pyriform aperture augmentation with biomaterials as well as maxillary anterior orthodontics. All patients received postoperative rapid orthodontic treatment for 6-12 month after 2 weeks of operation. Using the straight arch wire techniques and the class Ⅲ intermaxillary traction, we removed the overcrowding upper and lower teeth, the compensatory axial tilt of teeth, and the deviation of the dental arch and maintained the neutral relationship of the molar. The mandible Hawley retaining devices were used during the maintaining stage. Results: The cases in study acquired satisfactory clinical outcome, which included the shortened overall treatment duration, the significantly improved facial features, the corrected occlusion relationship, and the restored function of mastication and temporomandibular joint. There were some complications as follows: intraoperative fracture (6 cases, 3.24%), the inferior alveolar nerve bundle injury (2 cases, 1.1%), and temporary open-bite that diminished by inter-maxillary elastic distraction one month after operation (19 cases, 10%). All cases in this study accepted postoperative orthodontic treatment. Follow-up time ranged from 6 months to 5 years. The cephalometric analysis results of 126 cases who had complete image data and over 6 months of follow-up showed that hard and soft tissue indexes were restored to normal range after combined orthognathic-orthodontic treatment. The stability of the maxillary and occlusive relationship of SFA(surgery-first approach) was similar to that of the COS(conventional orthodontics-first system) [relapse ratio=(T2-T1)/(T1-T0)×100%]. Over six months of follow-up , SNB and ANB showed that the average relapse ratio were 22% and 19.8%, whereas the relapse angle are less than 2°. Conclusions The Surgery-first approach could be used to treat most patients with Angle skeletal Class Ⅲ malocclusion, but the indications and the surgical procedures should be noticed and chosen.