# A Prospective Study on Accuracy of Computer-Based Fully Guided Versus Pilot-Guided Implant Surgery
## 1 Introduction  
Since the introduction of the osseointegration concept, the method of implant surgery and prosthetic treatment has undergone many changes. In the initial implant restoration, it was most important to achieve successful bone adhesion considering the remaining bone as much as possible. Afterwards, the restoration was performed in accordance with the implant and the surrounding teeth. However, as successful osseointegration became more common and the success rate of bone graft for the areas of residual bone deficiency increased, it changed into a prosthetic-driven treatment. This is to establish a prosthetic plan in consideration of the patient's aesthetics and functionality, and then perform the implant surgery according to the position of the prosthesis. This prosthesis-driven implant placement concept is becoming more important in the restoration of teeth using implants, and morerecently, computer-aided design/computer aided manufacturing (CAD/CAM) technology has been developed more rapidly [1,2].  
In the prosthetic-driven implant placement concept, correlation between available bone and ideal tooth position is important. This can be achieved through preparation of diagnostic casts, diagnostic wax up of the restoration, and radiographic stent representing the ideal tooth position before patient imaging. Then the customized surgical guide can be prepared for accurate transfer of implant planning for clinical application [3]. In combination with implant planning software and 3D imaging modalities, position of planned implant could be transferred from the computer to the patient mouth through computer-based surgical guides. Computer-assisted surgery (CAS) systems provide a significant increase in implantation precision compared with non-guided implantation surgery. Moreover, they provide minimally invasive, predictable, and shorter time surgery [4].  
For successful implants, evaluations of anatomical limitations are necessary to perform the additional surgeries, such as bone grafts, sinus grafts before implant surgery [4,5]. Previously, surgical guides have been used for the reference of the placement position [4, 5, 6, 7], therefore these kinds of the surgical guide was provided only for placement position. A computer software was developed to help us simulate virtually implant placement and predict the completion of the prosthesis [8,9]. However, implant surgery using a guide system has a disadvantage in that the volume and height of the instrument is increased by adding a portion for the guide. In addition, as the guide system for each manufacturer is different, additional system costs are incurred. This results in a dependency on the manufacturer's system. Therefore, if the guide system is used only to determine the implant position and path of the implant, and the operation can be performed in the conventional manner using the implant placement protocol what the operator needs, it will be possible to create a more operator-driven surgical environment and patient discomfort could be reduced.  
This paper aims to evaluate the accuracy of computer-based pilot-guided implant surgery in comparison with fully guided implant surgery and to evaluate the efficacy of computer-guided implant surgery.