# A Prospective Study on Accuracy of Computer-Based Fully Guided Versus Pilot-Guided Implant Surgery
## 4 Discussion
However, although the error value was slightly lower in the case of the tooth-supported guide, it was not statistically significant. This is thought to be due to the large proportion of patients recovering from multiple missing teeth. Tooth-supported guide was used in 17 of 20 patients. Three or more consecutive missing teeth were repaired in six patients (three pilot-guided and three fully guided), and the cantilever type tooth-supported guide was used for 11 patients (five guided patients and six fully guided patients) because of the edentulous area in the posterior region. In addition, unlike mucosa-supported guide, the guide used in this study extracted bone surface and used the bone-supported method. The angular error of the implant placed in the anterior area was significantly lower than the implant placed in the posterior area, but the distance error was higher than the posterior area. In particular, the error value (dy) of the bucco-lingual position in the shoulder area was significantly higher than that of the posterior region. However, there was no significant difference between the pilot-guided and fully guided cases. It is thought to have affected the difference of the errors between the anterior and posterior area that is the pilot-guided (ten anterior implants) showed less angulation errors and higher dy errors than the fully guided (four anterior implants) in this study. Most of the implants in this study were placed using the open flap technique and a small number of implants were placed through the flapless technique. The actual results showed similar deviations. This may be because the flapless technique is mainly used when the number of implants is expected to be sufficient due to the small number of implants placed at the same time. In fact, in this study, we designed a guide using open flap and extracting the surface from bone in the case of Kennedy Class 2 or full edentulous area. It is considered that flap or flapless has no significant effect on the results of this study. In addition, the difference between the guide design method of the pilot guide and the fully guide, the 3d printing method used, and the post-processing method may also influence the difference. [PERSON] et al. reported that deviation of 0.04-0.26 mm and \(\sim\)2\({}^{\circ}\) can be shown depending on the printing layer thickness and angulation setting value [18]. In this study, the guide of pilot-guided surgery was designed by the operator, and the guide of fully guided surgery was designed by the manufacturer and confirmed the planned data. Because of the different 3D printer and post-processing methods used, these differences may have caused errors. Recently, many articles have been published on the accuracy of surgery using 3D printed implant surgical guides. [PERSON] et al. [5] compared a total of 24 papers in systematic review of the accuracy of the computer-assisted implant placement protocol and they reported that an average error of 1.12 mm was confirmed at the entry point and an average error of 1.39 mm at the apex. Compared with the results of this study, the pilot-guided error was slightly higher than the above average (1.33 mm, 1.54 mm) and slightly lower for fully guided (0.96 mm, 1.38 mm), but both results were acceptable. In this study, distance between virtually planned and placed implants was evaluated by superimposition of preoperative planning data and postoperative data. Although it is considered the gold standard method for accuracy measurement, other measurement methods were developed in the literature to avoid additional radiation to the patient, but no available data to prove its superiority over the superimposition gold standard method [19]. The assessment of bone loss after one year in both the groups showed an average of 0.50 mm bone loss. There is no statistical significance. This is thought to be called a natural result because both the surgical procedure in the same procedure differ only when you are using a surgical template in progress.