Investigation of stresses in environmental tissue analysis of zigomatic and dental implants applied with different planning in atrophic toothless maxilla rehabilitation by finite element analysis

In advanced atrophies in the posterior maxilla, implant supported prostheses using zygomatic bone for prosthetic rehabilitation are one of the treatment options. Zigoma implants applied for this purpose increase the success of surgical procedures by decreasing the morbidity and procedure time in the excess atrophic posterior maxilla. It also eliminates the need for additional surgical procedures. In our study, a model showing posterior atrophy was obtained by using computerized tomographic records. The aim of this study was to select the most appropriate surgical planning according to the stress values of the forces applied to this model by applying different number of zygoma implants and dental implants which different number and different localization. In our study, one zigoma implant on the right and left sides in group 1 model, two zigoma implants on the right and left sides of the group 2 model, in group 3 model, a zygoma implant to the right and left maxilla and a dental implant to the right and left 1st premolar teeth, in group 4 model, a zygoma implant to the right and left maxilla and a dental implant to the right and left lateral teeth, in group 5 model, a zygoma implant to the right and left maxilla and a dental implant to the right and left lateral teeth and a dental implant to the right and left 1st premolar were applied. The zigoma implants (Nobel Biocare AB, Goteborg, Sweden) used in the study were 4 mm in diameter and 35 mm long, and dental implants (Nobel Biocare AB, Goteborg, Sweden) were 3.5 mm in diameter and 10 mm in length. The zygoma implants were placed by extrasinus method and 150 N were applied vertically in the prosthetic superstructure from 2-4-6-7 teeth and 50 N force was oblique at 30 . As a result of the forces applied in the study, the stress values of the zygoma implant and the metal substructure and the maximum stress values of the zygomatic bone and maxillary molar region alveolar bone were examined by finite element stress analysis. As a result of our study, group 2, group 4 and group 5 models were close to each other and the least stress values were measured, while the group 1 model was seen as the group with the highest stress value. Based on these results, it has been concluded that increasing the number of zygoma implants or dental implants reduces stresses and localization of the dental implant in addition to the zygomatic implant is important for stress values. Keywords: Atrophic maxilla, zygomatic implant, dental implant, finite element stress analysis