Читать книгу Management of Complications in Oral and Maxillofacial Surgery - Группа авторов - Страница 83

Virtual surgical planning (VSP) provides an opportunity to plan and simulate the surgery on a computer three‐dimensionally preoperatively including the prosthetic plan. Guided surgery allows for the use of surgical stents fabricated utilizing the VSP and a 3D printer. Altogether, this contributes to simplification of the implant procedure, reduced operative time, accurate implant placement, and prevention of complications such as nerve injury and maxillary sinus perforation. A split mouth randomized case series of 12 subjects in 2019 [8] concluded that angular deviation of the implants placed by guided virtual surgery was lower as compared to implants placed by conventional freehand surgery. However, it is important to understand that despite the advances in technology, errors can occur with the use of VSP and guided surgery, leading to poor implant positioning, making prosthodontic rehabilitation challenging and ultimately compromising functional and esthetic results. Inaccuracies can be incurred at every step in the VSP process, from data gathering (CBCT [cone‐beam CT] acquisition) to dental implant placement. For example, poor CBCT resolution, patient movement during the CBCT, and scanning of an ill‐fitting barium‐impregnated prosthesis (if used) will result in a faulty preoperative database and inaccurate planning and fabrication of an imprecise surgical guide. Another source of error includes the potential for drill deviation during sequential implant osteotomies, due to an inherent tolerance of the sleeve inserts that allow a certain degree of malalignment [9, 10]. Lastly, failure to seat and stabilize the surgical guide appropriately during the surgery can lead to several complications, such as injury to vital structures and poor anatomical placement of implants. As such, it is important to recognize that tooth‐supported surgical guides are more stable than bone‐borne guides, and least stable are the mucosa‐borne guides. Guide pins can be used to stabilize the guides during implant placement to prevent iatrogenic movement. The surgeon should perform periodic verification of the sequential osteotomies during the placement of dental implants, especially in the areas of vital structures. For a minimal deviation during implant placement with a surgical guide, it is crucial to place the drill in the center of the guide, and parallel to the sleeve/cylinder [9, 10]. Additionally, the use of more restrictive longer drill keys and sleeves may improve accuracy and provide more optimal outcomes [9, 10]. In view of concerns associated with the use of surgical guides, dynamic navigation systems have gained acceptance in implant surgical therapy in an attempt to improve precision and accuracy. Table 3.4 delineates the differences between static implant surgical guides/stents and dynamic implant navigation systems [11, 12].