• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.402-407
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• 2010

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 (${\pm}0.73$) mm at the occlusal center, 1.23 (${\pm}0.67$) mm at the apical center, and the axis error between the two fixtures was $3.25^{\circ}C$ (${\pm}3.00$). 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.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.175-184
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• 2011

With a development of implant restoration technique, there are increasing use of computer-guided system for edentulous patients. It was carried out simulated operation based on CT information about patient's bone quantity, quality and anatomical landmark. However, there are some difference between the programmed implant and post-operative implant about it's position. If the deviation was severe, it could happen a failure of 'passive fit' and not suited for path of implant restoration. The aim of this presentation is to evaluate about a degree of deviations between programmed implant and post-operative implant. Five patients treated by 'NobelGuide' system (Nobel Biocare AB, G$\ddot{o}$teborg, Sweden) in Department of Prosthodontics, Inha University were included in this study. The patients were performed CT radiograph taking and intra-oral impression taking at pre-operation. Based on CT images and study model, surgical stent was produced by NobelBiocareTM. To fabricated a pre-operative study model, after connected lab analog to surgical template, accomplished a pre-operative model using type 4 dental stone. At final impression, a post-operative study model was fabricated in the conventional procedures. Each study model was performed CT radiograph taking. Based on CT images, each implant was simulated in three dimensional position using $Procera^{(R)}$ software (Procera Software Clinical Design Premium, version 1.5; Nobel Biocare AB). In 3D simulated model, length and angulation between each implant of both pre- and post-operative implants were measured and recorded about linear and angular deviation between pre-and post-operative implants. A total of 24 implants were included in this study and 58 inter-implant sites between each implant were measured about linear and angular deviations. In the linear deviation a mean deviation of 0.41 mm (range 0~1.7 mm) was reported. In the angular deviation, a mean deviation was $1.99^{\circ}$ (range $0^{\circ}{\sim}6.7^{\circ}$). It appears that the both linear and angular mean deviation value were well acceptable to application of computer-guided implant system.