Analysis of Linear and Angular Deviations of Implants Installed With a Tomographic-Guided Surgery Technique: A Prospective Cohort Study
The aim of this study was to evaluate the linear and angular deviations of the implants installed by the computerized tomography (CT)–guided surgery technique. Eighteen patients who underwent implant insertion by means of CT-guided surgery participated in this study. Ten of these patients had a fully edentulous maxilla, and 8 had a fully edentulous mandible. The patients received a total of 115 implants, of which 81 implants were installed in the maxilla and 34 installed in the mandible. Tomographic guides were made for tomographic examination in both the upper and lower jaws. After the image acquisition, the virtual planning of the positioning of the implants was performed in relation to the previously made prosthesis. The measurement of the linear and angular deviations between the virtual planning and the final position of the implants was performed with the overlap of the planning and postoperative tomography. There were no differences in the linear and angular deviations of the implants installed in the maxilla and mandible. Compared with the coronal region, there was a trend of greater linear deviations in the apical regions of the implants and a greater tendency toward deviations in the posterior regions than in the anterior regions of both arches. The CT-guided surgery promoted the installation of implants with high accuracy and allowed the installation of straight pillars in all cases evaluated. The linear deviations were not different in the different regions of the mouth or in the different portions of the implants.
Method for surgical guide confection. (a) Tomographic guides with radiopaque markings of gutta percha in the region of the first molars and central incisors for tomographic examination in both the upper arch and the lower arch. (b) Example of implant installation planning in the maxilla. (c) Example of implant installations in the mandible.
Surgical procedure for implant placement. (a) Surgical guides made for installation of the implants. It was noticed that the guides were kept fixed in the mucosa by screws that were inserted to allow the stabilization of the guides to improve their stability. (b) Insertion of the implants. It can be noticed that the guides used were total-type surgical guides, which allowed the installation of the implants with the surgical guide in position. (c) Implants installed in a good position. It can be observed that it was not necessary to open the flap, which promotes better patient comfort with a reduction of swelling and pain sensation, besides reducing the surgical and clinical time, since the immediate load can be applied on the implants just after the implant placements if a good primary stability is achieved.
Clinical aspect of the prothesis. (a) Front view of the final prothesis. (b) Posterior view of the final prothesis. (c) Clinical condition of the final prosthesis protocol installed.
Model of the method of analysis of deviations of the position of the implants installed compared with the position of the implants planned, where distance D1 was calculated considering the linear distance between the points at the apex of the implant, distance D2 was calculated considering the linear distance between the points in the center of the implant, and D3 represents the linear distance between the points at the implant platform. The angle A1 was calculated in degrees between the vectors vt planned and vt installed.
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