Accuracy Evaluation of Computed Tomography–Derived Stereolithographic Surgical Guides in Zygomatic Implant Placement in Human Cadavers

Abstract

Presurgical planning is essential to achieve esthetic and functional implants. For implant planning and placement, the association of computer-aided design (CAD) and computeraided manufacturing (CAM) techniques furnishes some advantages regarding tridimensional determination of the patient's anatomy and fabrication of both anatomic models and surgical guides. The goal of this clinical study was to determine the angular deviations between planned and placed zygomatic implants using stereolithographic surgical guides in human cadavers. A total of 16 zygomatic implants were placed, 4 in each cadaver, with the use of stereolithographic (SLA) surgical guides generated by computed tomography (CT). A new CT scan was made after implant insertion. The angle between the long axis of the planned and actual implants was calculated. The mean angular deviation of the long axis between the planned and placed implants was 8.06 6 6.40 (mean 6 SD) for the anteriorposterior view, and 11.20 6 9.75 (mean 6 SD) for the caudal-cranial view. Use of the zygomatic implant, in the context of this protocol, should probably be reevaluated because some large deviations were noted. An implant insertion guiding system is needed because this last step is carried out manually. It is recommended that the sinus slot technique should be used together with the CT-based drilling guide to enhance final results. Further research to enhance the precision of zygomatic implant placement should be undertaken.

Flapless versus Conventional Flapped Dental Implant Surgery: A Meta-Analysis

“…These guides are manufactured in such a way that they match the location, trajectory, and depth of the planned implant with a high degree of precision. As the dental practitioner places the implants, the guides stabilize the drilling by restricting the degrees of freedom of the drill trajectory and depth [36]. It was stated that by using computer-assisted surgery predictability, precision and safety in flapless dental implantology are ensured [12].…”

“…However, the precision of the whole procedure depends largely on the ability to position accurately the drill guide, and to maintain that stable position during the whole procedure [36]. In the case of the placement of implants in completely edentulous jaws, there must be a way to assure the stability of the drill guide, and this is done by fixing the surgical guide onto the bone by osteosynthesis screws.…”

Tilted versus axially placed dental implants: A meta-analysis

“…Pterygomaxillary and zygomatic implants could be used, but these techniques present considerable surgical complexity. [4][5][6] The use of tilted implants in the anterior or posterior maxillary sinus walls may be used instead of maxillary sinus elevation or bone grafts, resulting in a simpler and less time-consuming treatment, in significantly less morbidity, in decreased financial costs associated with those procedures, and in a more comfortable postsurgical period for the patients. 7,8 Researchers have been trying to evaluate whether the insertion of tilted implants may influence the survival of dental implants.…”

Linear and Angular Deviations of Implants Placed in Experimental Casts with Stereolithographic Drill Guides Fixed by O'ring Ortho Implant Devices

“…Angular deviations close to these values are expected when this technique is used, and must be considered when one intends performing an implant placement procedure with SLA templates (3)(4)(5)(9)(10)(11)(16)(17)(18)(19)(21)(22)(23)(24). Devices that guide the drills and that adapt to the metal sleeves are 0.2 mm wider than the drills diameter, thus allowing an angular deviation until 5° (1).…”

“…Nevertheless, deviations in the position of planned and placed implants have usually been reported in studies assessing this technique (3,9,10). These deviations increase the risks of fenestrations and damage to noble structures, in addition to making immediate placement of the denture impossible because of the difficulty of adapting it to the implants, which implicates in the need of large occlusal adjustments.…”