Computer Aided Designing-Computer Aided Milling in Prosthodontics: A Promising Technology for Future.

Computer aided designing-computer aided milling (CAD-CAM) technology was introduced to dentistry way back in 1971. Over the years there has been a constant upgradation in the quality and popularity of its application to dentistry. CAD-CAM fabricated prosthesis though initially were considered costly and technique sensitive, nowadays they are being extensively used because of advancements in various CAD-CAM systems that have gained popularity. Th e ease of work and reduced chair side time makes them a boon while providing prosthodontics treatment. Dental CAD-CAM systems are being used not only for crowns and bridges, inlays and onlays but also for fabrication of removable prosthesis, stents, and implant components. Th is article reviews the evolution of the CAD-CAM system and its applications in the fi eld of dentistry over the past two and a half decades.

Implant surgery based on computer simulation surgical stent and the assessment with the image fusion technique

INTRODUCTION: The planning of implant surgery is an important factor for the implant prosthesis. Stereolithographic (SLA) surgical stents based on a computer simulation are quite helpful for clinicians to perform the surgery as planned. Although many clinical and technical trials have been performed for computed tomography (CT)-guided implant stents to improve the surgical procedures and prosthetic treatment, there are still many problems to solve. We developed a system of a surgical guide based on 3 dimensional (3D) CT for implant therapy and achieved satisfactory results in the terms of planning and operation. MATERIALS AND METHODS: Fifteen patients were selected and 30 implant fixtures were installed. The preoperative CT data for surgical planning were prepared after obtaining informed consent. Surgical planning was performed using the simulation program, Ondemend3D In2Guide. The stents were fabricated based on the simulation data containing information of the residual bone, the location of the nerve, and the expected design of the prostheses. After surgery with these customized stents, the accuracy and reproducibility of implant surgery were evaluated based on the computer simulation. The data of postoperative CT were used to confirm this system using the image fusion technique and compare the implant fixtures between the planned and implanted. RESULTS: The mean error was 1.18 (+/-0.73) mm at the occlusal center, 1.23 (+/-0.67) mm at the apical center, and the axis error between the two fixtures was 3.25degrees (+/-3.00). These stents showed superior accuracy in maxilla cases. The lateral side error at the apical center was significantly different from the error at the occlusal center but there were no significant differences between the premolars, 1st molars and 2nd molars. CONCLUSION: SLA surgical stents based on a computer simulation have the satisfactory accuracy and are expected to be useful for accurate planning and surgery if some errors can be improved.