Surgical guide may not be significantly helpful for experienced specialists in simple cases
dehiscence
DEHISCENCE
Based on the results of this study, the coronal and apical distance and the angular deviations showed no significant difference between Group ISG and IFH in total and in subgroup IA and IB.Currently, it remains controversial whether it is more beneficial for dental implantation to use a surgical template than the traditional freehand approach in consideration of different situations. The critical review by Pozzi A. et al. suggested that there was limited evidence supporting the clinical advantage of using computer-guided surgery compared to conventional freehand implant placement for the treatment of single-tooth gap [Nevertheless, a systematic review and meta-analysis by Chen et al. reported that with the technology of computer-aided surgical template, implant placement may be more accurate than freehand operation [For most clinical situations, free-hand implantation with CBCT aiding can receive a clinically desirable position without significant error affecting subsequent prosthetics and functions. For relatively complicated cases, including inadequate alveolar bone quantity (vertical and horizontal bone defects) and limited bone available in maxillary anterior area, low bone density, multiple implant sites, implant sites near vital and complex anatomical structure (e.g., nerves or sinuses), the difficulties and risks of the implant surgeries may be dramatically increased. The surgical guides are strongly recommended in these conditions to provide good assistance and security for surgeons including very experienced ones. The self-tapping feature of the implant may result in more variation in accuracy, especially in situations with soft bone and areas with fenestration or dehiscence of the bone.There are five main factors that may presumably influence the overall outcome: type of jaw (maxilla/ mandible), type of edentulous site (one single-tooth gap/interrupted gaps of multiple single-units/continuous partially edentulous gap of multiple units/ free-end edentulous /full-arch edentulous), type of template support (tooth-/bone-/mucosa-supported), type of guided surgery (fully guided placement/partially guided / freehand placement) and the surgical technique (flapless/open flap) [Meanwhile, several factors leading to inaccuracy of surgical guides required extra attention during each step of the workflow: presence of debris in the drilled hole preventing the implant from reaching its final position, resilience of mucosal tissues, setting of the radiological gray values during segmentation, improper seating of the template and deformation of the guide during surgery.