ObjectivesThis study evaluated the microleakage at the implant/abutment interface of external hexagon (EH) implants and abutments with different amounts of bacteria and tightening torques. Material and MethodsA bacterial suspension was prepared to inoculate the implants. The first phase of this study used nine EH implants and abutments that were divided into three groups with different amounts of bacterial suspension (n=3): V0.5: 0.5 µL; V1.0: 1.0 µL e V1.5: 1.5 µL, and tightened to the manufacturer's recommended torque. The second phase of this experiment used 27 assemblies that were similar to those used in the first phase. These samples were inoculated with 0.5 µL of bacterial suspension and divided into three groups (n=9). T10: 10 Ncm; T20: 20 Ncm and T32: 32 Ncm. The samples were evaluated according to the turbidity of the broth every 24 hours for 14 days, and the bacteria viability was tested after that period. The statistical evaluation was conducted by Kruskal-Wallis testing (p<.05). ResultsDuring the first phase, groups V1.0 and V1.5 was presented with bacterial contamination in all samples after 24 h. During the second phase, two samples from group T10 and one from T20 presented positive results for bacterial contamination. Different amounts of bacterial solution led to overflow and contamination during the first 24 h of the experiment. The tightening torques did not statistically affect the microleakage in the assemblies. However, the group that was tightened to 32 Ncm torque did not show any bacterial contamination. ConclusionAfter 14 days of experimentation, the bacteria were proven to remain viable inside the implant internal cavity.

The purposed treatment allowed a time and money saving resolution for fractured abutment screws.

The current study evaluated prosthetic dental crowns obtained by optical scanning and a computer-aided designing/computer-aided manufacturing system using micro-computed tomography to compare the marginal fit. The virtual models were obtained with four different scanning surfaces: typodont (T), regular impressions (RI), master casts (MC), and powdered master casts (PMC). Five virtual models were obtained for each group. For each model, a crown was designed on the software and milled from feldspathic ceramic blocks. Micro-CT images were obtained for marginal gap measurements and the data were statistically analyzed by one-way analysis of variance followed by Tukey's test. The mean vertical misfit was T = 62.6 ± 65.2 μm ; MC = 60.4 ± 38.4 μm; PMC = 58.1 ± 38.0 μm, and RI = 89.8 ± 62.8 μm. Considering a percentage of vertical marginal gap of up to 75 μm, the results were T = 71.5%, RI = 49.2%, MC = 69.6%, and PMC = 71.2%. The percentages of horizontal overextension were T = 8.5%, RI = 0%, MC = 0.8%, and PMC = 3.8%. Based on the results, virtual model acquisition by scanning the typodont (simulated mouth) or MC, with or without powder, showed acceptable values for the marginal gap. The higher result of marginal gap of the RI group suggests that it is preferable to scan this directly from the mouth or from MC.

The IC implant with smaller diameter did not result in reduction of elastic limit when compared with the REH implants. Nevertheless, the reduction of 0.45 mm of the hexagonal connection implant's diameter has significantly diminished the elastic limit.

Aim: To evaluate the microleakage at the implant-abutment (I-A) interface of Morse tapered implants inoculated with different volumes of bacterial suspension. Methods: Morse tapered I-A sets were selected and divided in two groups depending on the type of abutment: passing screw (PS) and solid (S), and then subdivided into four subgroups (n=6) according to the suspension volume: PS1: 0.1 µL; PS3: 0.3 µL; PS5: 0.5 µL; PS7: 0.7 µL; S1: 0.1 µL; S3: 0.3 µL; S5: 0.5 µL and S7: 0.7 µL. A control test was performed to verify the presence of external contamination during the inoculation and the implants were incubated for microbiological analysis. The microleakage was evaluated every 24 h for 7 days by the clarity of solution. After this period, the implants were disassembled for confirmation of bacterial viability. Results: All the specimens with 0.7 µL and one sample of S5 presented turbidity in the control test indicating external contamination, and were excluded from the study. After 7 days of observation, none of the specimens presented positive results for microleakage and the bacterial viability was confirmed in all specimens. The 0.1 µL and 0.3 µL volumes did not present bacterial microleakage, meaning that these volumes may be inadequate for analysis. Conclusions: None of the sets evaluated showed bacterial microleakage at the I-A interface and the volume of 0.7 µL exceeded the internal capacity of the implants.

Microscopic measurements are widely used in scientific research and the correct equipment to realize these evaluations could be critical to determine study results. Regarding microscopic measurements, three of the most used methods are: Optical Microscopy (OM), Scanning Electron Microscopy (SEM), and Micro-computed Tomography (MCT). It is important to select the best method for assessing diverse parameters, considering operational characteristics of the method, the equipment efficiency, and the machinery cost. Therefore, the main objective of this study was to define which is the most useful measurement method for assessing magnitudes below 0.4 mm. Ten dental implants, with known dimensions as defined by the manufacturer were randomly distributed. Two blinded observers assessed the distance between the second and the third screw vortex of the implants using three suggested methods. The true distance was defined to be 0.5 mm. The assessed distances were: 0.597±0.007mm for OM, 0.578±0.017mm for SEM, and 0.613±0.006mm for MCT. The assessed distances were significantly different when the methods were compared (P>0.01). All measurements were into the CAD tolerances. It was possible to conclude that linear measurements between 595 and 605 μm could be performed by any of the described technologies.

No abstract

New techniques have been developed in order to reduce the time of treatment, minimizing the cost and the psychological and surgical trauma of the patients, especially in regions with aesthetic involvement. The immediate placement of dental implants is a reality and clinical studies have shown that the success rate of immediate implant is similar to that placed after bone repair. The objective of this study is to present a clinical case of a immediate implant placement to substitute a central incisor after atraumatic extraction, through the use of Neodent root extractor. Immediate implant placement and immediate loading, when correctly indicated, are a quick and safe alternative for the rehabilitation of affected teeth , they also allow the preservation of bone architecture , and provides the patient a lower number of surgeries and consequently less morbidity. It also promotes psychological comfort, immediate aesthetic and functional satisfaction to the patient.