Examination of gutta-percha cones for microbial contamination during chemical use

OBJECTIVE: The aim of this study was to evaluate the degree of microbial contamination in packaged gutta-percha cones before and during use in clinical conditions. MATERIAL AND METHODS: Sealed packages of #15-40 gutta-percha cones were opened under aseptic laboratory conditions. Two gutta-percha cones from each size were randomly drawn and added to tubes containing glass beads and 750 µL of saline. The tubes were vortexed, serially diluted and samples of 250 µL were cultured on agar plates. The plates were incubated at 37ºC for 3 days and colonies were counted. The initially sampled packages were distributed to 12 final year dental students. The packages were collected at the end of the first and the third clinical practice days and sampled as described above. RESULTS: Baseline microbial counts did not exceed 3 CFU. At the end of the first and the third day, additional contamination was found in five and three of the packages, respectively. The ratio of contaminated packages at the first day and the third day was not significantly different (z-test; p > 0.05). The numbers of microorganisms cultured at the first day (8 ± 9.9 CFU) and the third day (4.5 ± 8.3 CFU) were not significantly different (Wilcoxon signed-rank test; p > 0.05). No significant correlation was found between the number of filled root canals and cultured microorganisms at either the first day (Spearman's rho; r = 0.481, p = 0.113) or the third day (r = -0.034, p = 0.917). CONCLUSIONS: Gutta-percha cones taken directly from manufacturer's sealed package harbored microorganisms. Clinical use of the packages has been found to be associated with additional contamination of the gutta-percha cones. The counts of cultured microorganisms did not correlate well with the number of filled root canals

Comparison of the cleaning efficacy of the FKG race system and hand instrument in molar root canal Comparação da eficácia de limpeza entre o sistema FKG race e instrumentos manuais em molares inferiores

INTRODUCTION AND OBJECTIVE: The aim of this study was to evaluate the ability of root canal cleaning of the RaCe rotary instrumentation system (FKG Dentaire - La-Cheaux-de Fonds - Switzerland), compared to manual filing with Stainless Steel K-files (Maillefer Instruments - Ballaigues - Switzerland). MATERIAL AND METHOD: Twenty extracted human teeth (maxillary molars) were selected and their pulp tissue was removed after coronal access. The root canals were filled with a dye (India ink) and allowed to dry for 48 hours, followed by establishment of the working length of the mesiobuccal root; then, half of the specimens were instrumented by the modified Oregon technique and the other half were instrumented by crown-down sequence of the RaCe system. After preparation, the teeth were longitudinally sectioned and evaluated according to the amount of remaining dye. RESULTS: Data obtained were registered as numerical scores, and the arithmetic means were compared between groups using the Mann Whitney test. Both techniques were unable to completely clean the interior of the root canals, with a better performance of the manual technique only at the middle third. CONCLUSION: It could be concluded that the RaCe system was able to provide satisfactory cleaning, similar to that obtained by the manual instrumentation technique.<br>Objetivo deste trabalho foi avaliar a capacidade de limpeza de canais radiculares por meio do sistema de instrumentação RaCe (FKG Dentaire - La-Cheaux-de Fonds - Suíça) em comparação à instrumentação manual por meio de limas tipo K-File (Maillefer Instruments - Ballaigues - Suíça). Foram selecionados 20 dentes humanos extraídos (molares superiores) que tiveram seu conteúdo radicular removido após realização da abertura coronária. Os canais foram preenchidos com corante (tinta nanquim) e após 48 horas para secagem, realizou-se a odontometria da raiz mésio-vestibular. Metade dos espécimes foi instrumentada pela técnica de Oregon modificada e a outra metade pela seqüência crown-down preconizada pelo fabricante do sistema RaCe. Após o preparo, os dentes foram seccionados longitudinalmente e avaliados de acordo com a quantidade de corante remanescente. Os dados obtidos foram registrados por meio de escores numéricos e as médias aritméticas foram analisadas entre os grupos pelo teste de Mann Whitney. Ambas as técnicas foram incapazes de limpar completamente o interior dos canais radiculares sendo que a técnica manual desempenhou limpeza significantemente superior apenas no terço médio. Conclui-se que o sistema RaCe foi capaz de desempenhar uma limpeza satisfatória sendo próxima àquela conseguida pela técnica de instrumentação manual

A survey of adoption of endodontic nickel-titanium rotary instrumentation part 2: community and hospital dental practitioners in Wales

Objectives: To assess adoption of endodontic nickel-titanium rotary technology (NiTi) by community and hospital dental clinicians within Wales and identify factors that may restrict uptake. Design: Postal questionnaire. Setting: Community and hospital-based dentists in Wales. Methods: Community and hospital-based dentists with a remit for provision of restorative dentistry (community dental setting = 32; hospital dental setting = 36) were approached regarding their usage or otherwise of nickel-titanium rotary instrumentation for endodontic treatments. The postal questionnaire took the form of an anonymous survey comprising 12 questions. These questions covered usage parameters, satisfaction and training and broached reasons for NiTi avoidance. Results: The response rate was 77%. NiTi rotary instruments were used routinely by an encouraging 82% of those in the hospital-based restorative dental services but only 13% of community staff. Factors cited as being implicated in the decision to avoid their use included cost (62% of responses) lack of training and the perceived lack of benefit. Conclusion: The adoption of rotary NiTi endodontic technology by the hospital dental practitioners of Wales is encouraging with the majority having converted to such systems in excess of three years prior to the survey. There was, however, a significant disparity in NiTi usage between community and hospital settings, the implications for which and possible solutions for increased training and uptake are discussed