Exploration Of Manufacturing Splint For Orthognathic Surgery Using The CBCT Data And The Precision Study

Objective:The purpose of this study was to introduce a stereolythographic method for surgical splint manufacture using the CBCT data.Methods:Ten participants (five normal persons, five patients with orthognathic deformations) with ceramic brackets on their anterior and premolar teeth were included in this study. After 3-dimensional (3D) data acquisition by cone-beam computerized tomography (CBCT) from all participants and their plaster models, preoperative planning including segmentation, osteotomies and movements of the jaw bones was simulated using an interactive SurgiCase CMF software (Materialise Medical, Leuven, Belgium). Combining these two kinds of data, we could get the ideal occlusion. Setting a virtual splint between the tooth rows made it possible to encode the repositioning. After performing a Boolean operation, tooth impressions were subtracted from the virtual splint. The traditional surgical splints were made at the same time. Then plaster models were scanned separately using a surface scanner. Using these data, we made the standard splints. Finally, the fitting degree between the three splints to evaluate the investigative splint's precision and the clinical value. Results:For the ten participants, the averages of maximum error when the fitting degree between CBCT and surface scanner splints close to 100% were 0.524±0.151mm(maxillary),0.454±0.127mm(mandible). When the maximum error was 0.5mm, the averages between them were 99.368±1.532%(maxillary),99.932±0.154%(mandible). The averages of maximum error when the fitting degree between traditional and surface scanner splints close to 100% were 1.187±0.338mm(maxillary),1.140±0.393mm(mandible). When the maximum error was 0.5mm, the averages between them were 74.369±8.688%(maxillary),74.395±16.373%(mandible). There was no significant differences neither between normal persons and patients, nor between maxillary and mandible.Conclusion:Combining the plaster model with the craniofacial model can improve the clarity of the tooth surface imaging. Using ceramic brackets can reduce the artifacts around the teeth, and this makes the fitting more easily. The precision of our virtual splint is nice. But the application for the clinical surgery needs to be further studied.