Micro-computed tomography and bond strength analysis of different root canal filling techniques.

Introduction: The aim of this study was to evaluate the quality and bond strength of three root filling techniques (lateral compaction, continuous wave of condensation and Tagger’s Hybrid technique [THT]) using micro‑computed tomography (CT) images and push‑out tests, respectively. Materials and Methods: Thirty mandibular incisors were prepared using the same protocol and randomly divided into three groups (n = 10): Lateral condensation technique (LCT), continuous wave of condensation technique (CWCT), and THT. All specimens were filled with Gutta‑percha (GP) cones and AH Plus sealer. Five specimens of each group were randomly chosen for micro‑CT analysis and all of them were sectioned into 1 mm slices and subjected to push‑out tests. Results: Micro‑CT analysis revealed less empty spaces when GP was heated within the root canals in CWCT and THT when compared to LCT. Push‑out tests showed that LCT and THT had a significantly higher displacement resistance (P < 0.05) when compared to the CWCT. Bond strength was lower in apical and middle thirds than in the coronal thirds. Conclusions: It can be concluded that LCT and THT were associated with higher bond strengths to intraradicular dentine than CWCT. However, LCT was associated with more empty voids than the other techniques.

Assessment of preload in carbon coated prosthetic screws

Introduction : The mechanical aspects of tightening screws over implants are important to ensure a successful prosthetic rehabilitation. Screw loosening is a common problem that can be avoided with passive adaptation of the components and an increased tensile force developed in the screw, a preload. Objective: This in vitro study evaluated the effect on preload of a carbon lubricant deposited on the surface of titanium alloy prosthetic screws: conventional Ti6Al4V and surface enhanced. Material and methods: Conventional titanium alloy prosthetic (n = 7) and carbon coating surface enhanced screws (n = 7) were compared. Each prosthetic screw supporting a metallic UCLA over an implant was tightened with the manufacturer’s recommended torque of 32 N.cm. The removal torque values, recorded for ten consecutive cycles of tightening and removal, were used to estimate the preload. Implant blocks were then sectioned and the interfaces were observed by light microscopy.Results: The lowest removal torque, and consequently the highest preload values, was achieved for the lubricated group in most cycles. The contacts between threads were located at the coronal aspect of all observed screw mating threads.Conclusion: Data indicate that the lower coefficient of friction of a carbon lubricant can generate higher preload. The machining precision observed produced the adaptation and regular contact interfaces.

Hábito de prescrição de antibióticos por especialistas em Endodontia

Introdução: a proposta do presente estudo foi determinar os hábitos da prescrição de antibióticos por especialistas em Endodontia, no que se refere ao tempo de uso,indicação e produto de primeira escolha. Métodos: um questionário com quatro perguntas foi entregue a 105 endodontistas do estado de São Paulo. Os resultados foram tabulados e comparados estatisticamente. Resultados: do montante dos entrevistados, 48,5% eram do sexo masculino e 51,5% do feminino. A amoxicilina foi o antibiótico de primeira escolha para 84,7% dos profissionais. No caso de pacientes alérgicos à penicilina, 47,6% dos entrevistados utilizam clindamicina e 42,8%, azitromicina. A grande maioria (79%) recomenda a administração do antibiótico por um período de 5 a 7 dias. Cerca de um terço dos entrevistados indica de forma inadequada a antibioticoterapia.Conclusão: a maior parte dos profissionais soube selecionar corretamente o antibiótico para pacientes alérgicos ou não à penicilina, assim como o tempo de administração. No entanto, ainda há profissionais que empregam inapropriadamente a antibioticoterapia, o que favorece a resistência bacteriana