Dr. Shruti Khaneja, Dr. Samarth Agarwal, Dr. Siddhi Tripathi and Dr. Swatantra Agarwal
Objective: The purpose of the study was to investigate if the use of tilted implants as distal abutments is biomechanically superior to the use of distal cantilevers. Methods: A 3-D edentulous maxillary model was generated from computed tomography images. Four implants were placed in the pre-maxilla and splinted with a titanium bar. Keeping the prosthesis length constant, six different configurations were evaluated with the distal implant varying in length (8 mm, 10 mm, 13 mm); angulation (0, 15, 30, 45°) and abutment angulation (0, 17, 30°). A vertical load (120 N) was applied on the titanium bar corresponding to the position of the left second premolar abutment. Von Mises stress values transmitted to the peri-implant bone and implant abutment junction were evaluated. Results: The maximum stresses recorded at the peri-implant bone and the implant abutment junction were 5.821 MPa and 8.261 MPa for 8 mm vertical implant; 5.358 MPa and 8.131 MPa for the 10 mm implant; and 4.897 MPa and 7.754 MPa for the 13 mm vertical implant. Tilted distal implants resulted in increased stress values for all variables: 8.906 MPa, 8.938 MPa and 8.994 MPa at the peri-implant bone and 14.636 MPa, 15.567 MPa and 16.872 MPa at the implant abutment junction for 15, 30 and 45° respectively. Conclusion: An increase in implant length resulted in a decrease in the stresses, whereas the tilted distal implants and abutments increased the stresses at the peri-implant bone and implant abutment junction of the implants.