THE EFFECT OF ANTERIOR-POSTERIOR SPREAD AND CANTILEVER LENGTH ON THE SUPPORTING STRUCTURES OF MAXILLARY SCREW RETAINED PROSTHESIS

Abstract

Purpose: The Target of this work was to study the effect of three different ratios of anterior-posterior spread to the cantilever length on the supporting structures of implant- screw retained maxillary prosthesis ; Materials and Methods: In this study, maxillary implant screw retained prostheses were placed in fifteen completely edentulous patients. Each patient received six implants in the maxilla. Patients were divided into three equal groups; Group I, II & III according to the ratio of anterior-posterior implant spread to the cantilevers lengths (CL/ AP). The / CL AP ratio was 1:1, 1:2 and 1:3 in the three groups respectively. In this Study, crestal bone height changes around each implant were evaluated at time of prostheses insertion, four, eight and twenty-four months later using CBCT. Results: The results of this study revealed that the least bone height loss was noticed in Group III. Statistically significant difference was reported between Groups I, II& III in bone height loss.Conclusion: Within the limitation of this study, it might be concluded that the cantilever extension to antero-posterior implant spread with 1:3 ratio might have induced the least crestal bone height loss around each implant in maxillary screw retained prostheses.