Comparative analysis of optical microscopy, scanning electron microscopy, and micro-computed tomography on measurements

Abstract: Microscopic measurements are widely used in scientific research and the correct equipment to perform 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. Aim: Therefore, the main objective of this study was to define which is the most useful measurement method for assessing magnitudes below 0.4 mm. Methods: 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. Results: 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. Conclusion: It was possible to conclude that linear easurements between 595 and 605 µm could be performed by any of the described technologies (AU)

Substituição e estética imediata na região anterior da maxila utilizando implante Drive e munhão anatômico / Replacement and immediate aesthetic in the anterior maxilla using Drive implants and anatomic trunnion

O aumento da exigência estética na reabilitação com implantes provocou uma mudança nos conceitos de tratamento dentro da Implantodontia. Novas técnicas vêm sendo desenvolvidas no intuito de diminuir o tempo de tratamento, minimizando também o custo e o trauma cirúrgico e psicológico dos pacientes, principalmente em regiões com envolvimento estético. A substituição imediata em Implantodontia consiste na instalação de implantes em alvéolos frescos imediatamente após a extração dentária e a confecção de um provisório diretamente sobre implante, na mesma sessão clínica. Isto é possível quando é alcançada uma estabilidade primária suficiente para que este implante seja submetido a cargas funcionais controladas. A técnica de substituição e estética imediata é um procedimento que oferece elevados índices de sucesso, uma vez que permite a diminuição do tempo de espera pela prótese definitiva, menor número de intervenções cirúrgicas, eliminação da utilização de prótese provisória re¬movível ou adesiva e favorece a manutenção dos tecidos peri-implantares, além de oferecer um relativo conforto psicológico ao paciente. O objetivo deste trabalho é relatar um caso clínico de substituição e estética imediata de um incisivo central superior fraturado, discutindo as vantagens desta técnica.

The demand for aesthetic results in reatment with dental implants has increased resulting on a change in Implantology. New techniques were developed in order to reduce the time of treatment minimizing costs, surgical and psychological trauma to the patients, especially in regions with aesthetic involvement. Immediate replacement consists on installing implants in fresh alveolus immediately after tooth extraction and preparation of a provisional crown directly over the implant, all in the same clinical session. This is possible when achieved enough primary stability is achieved, so the implant is subjected to controlled functional loads. The replacement and immediate aesthetics technique has a high success rate, since it allows re¬duction on the waiting time for definitive prosthesis, smaller number of surgeries, elimination of use of adhesive or removable prosthesis, assists the preservation of peri-implant tissues, besides offering elative psychological comfort to the patient. The objective of this study was to report a case of immediate replacement of a fractured maxillary central incisor, discussing the advantages of this technique.

Bacterial microleakage at the implant-abutment interface in Morse taper implants

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...

Micro-leakage at the implant-abutment interface with different tightening torques in vitro

OBJECTIVES: This 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 METHODS: A 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). RESULTS: During 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. CONCLUSION: After 14 days of experimentation, the bacteria were proven to remain viable inside the implant internal cavity.