This study aimed to analyze a novel technique to make screws with greater untightening resistance and to solve screw loosening in implant-supported single crowns. Thirty grade IV titanium straight abutments were screwed onto 30 external hex implants using grade IV titanium screws (30 Ncm). They were exposed to cyclic loading (300,000 cycles, 200 N). Samples were divided into 4 groups (15 samples per group): new screws (SCREW group) (control), reused screws (rSCREW group), new screws wrapped with polytetrafluoroethylene (PTFE) tape (PTFE group), and reused screws wrapped with PTFE tape (rPTFE group). Reverse torque values (RTVs) were recorded with a digitally calibrated implant motor. Mean RTVs observed were 14.46 N (±1.10 N) for the control group, 14.42 N (±1.22 N) for the rSCREW group, 19.97 N (±1.16 N) for the PTFE group, and 19.13 N (±2.38 N) for the rPTFE group. Statistically significant differences were found between RTVs of both groups employing screws without PTFE tape (SCREW and rSCREW groups) compared with those using screws wrapped with PTFE tape (PTFE and rPTFE) (p < 0.001). These results suggest that wrapping the implant–abutment screw with PTFE tape may effectively lower the risk of loosening and even constitute a solution when this complication occurs in implant single crowns.

Background and Aim Conclusions Methods and Materials ReferencesObjectives: The aim of this study was to evaluate a new design of the cervical portion of dental implant with the objective to increase the periimplantar tissues volume in the crestal area on mesio-distal aspects.Materials and Methods: Twenty-two tapered dental titanium implants with internal conical connection were implanted in healed alveolar sites of 22 patients. Eleven conventional Morse tapper implants design used as the control group, and 11 new implant design (PlusBone implant) formed the test group. The groups were randomized. Periapical radiographs and the implant stability quotient were evaluated in three times periods: immediately after implant placement (at baseline) (time 1), at 3 months (time 2) and 5 months (time 3). In the radiographic analysis, mesial and distal bone volume was calculated, taking into account the distortion rate for each radiograph as compared to the original implant measurements, from the difference between the initial and final measurements. The data were compared using statistical tests (α = 5%). Results:The radiographic measurements showed a significant increase in the bone volume for the implants of test group (p<0.05). The statistics analysis not demonstrated significant differences in the ISQ values between the groups when compared in each time (p<0.05). Conclusions:Within the limitations of this study, the findings suggest that more volume and more height values of the crestal bone of periimplantar bone may be expected in this new implant design.