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Objective: During the insertion of dental implants in the bone tissue, different torque values can be applied. However, the high applied torque can cause damage to the implant connection. Our study sought to evaluate, by measuring the angle of rotation of the insertion drive and, later microscopic observation, possible changes in the structure of implants of different diameters with 3 different types of connections after the application of 4 different torque intensities., Materials and Methods: Three hundred tapered dental implants and three hundred insertion drivers were used in the present study. Implants of 3.5 and 4 mm in diameter with 3 connection models were tested: external hexagon (EH), internal hexagon (IH) and Morse taper (MT). Then, sis groups were performed: EH3 group, EH4 group, IH3 group, IH4 group, MT3 group and MT4 group. The samples were submitted to the torque/torsion force at 4 intensities (n = 10 samples per group and intensity): 60, 80, 100 and 120 Ncm. The turning angle of the insertion driver was measured in each test. In addition, in 10 samples from each group, the maximum torque value supported by each implant model was measured. After the tests, all samples were inspected microscopically to describe the observed changes., Results: The maximum torque supported by the different implant models showed statistically significant difference (p < 0.0001). The values of the measured angles showed statistically significant differences between the torque values applied within each group (p < 0.001) and between groups with the same torque value (p < 0.001)., Conclusions: Within the limitations of the present study in vitro, the results showed that high torque values cause mechanical damage to the implants., Competing Interests: The authors have read the journal’s policy and have the following potential competing interests: SAG is a paid employee of Biotecnos and NBJr is a Director of Implacil De Bortoli. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

Purpose: This study aimed to evaluate the misfit of three different implant-abutment connections before and after cycling load., Materials and Methods: One hundred twenty dental implants and correspondent prefabricated titanium abutments were used. Three different implant-abutment connections were evaluated: Morse taper (MT group), external hexagon (EH group), and internal hexagon (IH group). Forty implants and 40 abutments were used per group. The parameters for the mechanical evaluation were set as: 360,000 cycles, load of 150 N, and frequency of 4 Hz. Samples were sectioned in their longitudinal and transversal axes, and the misfit of the implant-abutment connection was evaluated by scanning electron microscopy analysis. One-way analyses of variance, Tukey post hoc analyses (α = .05), and t test (P < .05) were used to determine differences between groups., Results: At the longitudinal direction, all the groups showed the presence of microgaps before cycling load; after cycling load, microgaps were reduced in all groups (P > .05). Transversally, only the MT group showed full fitting after cycling load compared with the other groups (EH and IH) (P < .0001)., Conclusion: The application of cycling load produces an accommodation of the implant-abutment connection in internal, external, and Morse taper connections. In the longitudinal direction, the accommodation decreases and/or eliminates the gap observed initially (before load). In the horizontal direction, Morse cone implant-abutment connections experience a complete accommodation with the elimination of the gap.

Purpose: The aim of this in vitro study was to assess the resistance to static fatigue of implants with different connections before and after implantoplasty., Materials and Methods: Sixty conical implants and 60 abutments were used; 4-mm-diameter versions were available for each model. Three groups (n = 20) were established based on the following implant connections: external hexagon (group 1), internal hexagon (group 2), and Morse taper (group 3). The implants of each group were submitted to a compressive load before (n = 10) and after the implantoplasty (n = 10). The wear was performed in a mechanical lathe machine using a carbide bur, and the final dimensions of each sample were measured. All groups were subjected to quasi-static loading at a 30-degree angle to the implant axis in a universal testing machine and 5 mm out of the implant support., Results: After the implantoplasty, the mean final diameter was 3.13 ± 0.033 mm for group 1, 3.23 ± 0.023 mm for group 2, and 3.25 ± 0.03 mm for group 3. The mean fracture strengths for the groups before and after the implantoplasty were, respectively, 773.1 ± 13.16 N and 487.1 ± 93.72 N in group 1; 829.4 ± 14.12 N and 495.7 ± 85.24 N in group 2; and 898.1 ± 19.25 N and 717.6 ± 77.25 N in group 3., Conclusion: Resistance to loading decreased significantly after implantoplasty, and varied among the three implant connection designs.