Objective: The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT) on the shear bond strength (SBS) of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI). Methods: One-hundred-ninety-two PfT were divided into four groups (n = 48): Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3, two drillings were done with a spherical diamond bur; Group 4, sandblasting was performed with 50-µm aluminum oxide. Before the experiment, half of the samples stayed immersed in distilled water at 37oC for 90 days. Brackets were bonded with Transbond XT and shear strength tests were carried out using a universal testing machine. SBS were compared by surface treatment and by ageing with two-way ANOVA, followed by Tukey’s test. ARI scores were compared between surface treatments with Kruskal-Wallis test followed by Dunn’s test. Results: Surface treatments on PfT enhanced SBS of brackets (p< 0.01), result not observed with ageing (p= 0.45). Groups II, III, and IV showed higher SBS and greater ARI than the Group 1 (p< 0.05). SBS was greater in the groups 3 and 4 (drilling, sandblasting) than in the Group 2 (grinding) (p< 0.05). SBS and ARI showed a positive correlation (Spearman’s R2= 0.57; p< 0.05). Conclusion: Surface treatment on PfT enhanced SBS of brackets, however ageing did not show any relevance. Sandblasting and drilling showed greater SBS than grinding. There was a positive correlation between SBS and ARI.
OBJETIVO: avaliar o efeito da aplicação do fluoreto de sódio (NaF 1,23%) sobre a superfície de braquetes de titânio e de aço inoxidável. METODOLOGIA: foram utilizados 15 braquetes de titânio, divididos em três grupos: A) grupo controle, composto por braquetes não submetidos a qualquer tipo de tratamento; B) braquetes imersos por 60 segundos em fluoreto de sódio e lavados com 20ml de água destilada por trinta segundos; C) braquetes imersos por 60 segundos em fluoreto de sódio e posteriormente submetidos à escovação por 15 segundos, sendo então lavados com 20ml de água destilada por trinta segundos. Para efeito comparativo, foram utilizados 15 braquetes de aço inoxidável, divididos em três grupos (Grupos A1, B1, C1) e submetidos aos mesmos procedimentos descritos. Todos os braquetes, antes e após o experimento, foram avaliados por inspeção visual e analisados ao microscópio eletrônico de varredura (Philips, modelo XL 30). RESULTADOS: a inspeção visual revelou uma mudança da coloração dos braquetes de titânio submetidos ao fluoreto de sódio (grupos B e C), apresentando-se escurecidos quando comparados aos acessórios do grupo A. Os braquetes de aço inoxidável não sofreram alteração cromática em nenhum dos grupos. CONCLUSÃO: através da análise por microscópio eletrônico de varredura, não foram constatadas alterações topográficas e químicas na superfície dos braquetes de titânio, assim como nos braquetes de aço inoxidável.
The direct restoration technique is the most used to treat the sequelae of dental caries. With the constant evolution of dental materials, emerged in the dental market Cention n (Ivoclar Vivadent), material belonging to the group of alkasite materials. This material has as proposal a higher mechanical resistance than the composite resin, with the similar color to the tooth and with good marginal sealing power. The present study aimed to compare the marginal infiltration of enamel in restorations using Cention n (Ivoclar Vivadent) with and without the use of adhesive and composite resin. Twenty one cavities were performed on the buccal surface of seven bovine incisor teeth. The cavities were divided into three groups: Group I - restoration with Cention n (Ivoclar Vivadent) without adhesive; Group II - restoration with Cention n (Ivoclar Vivadent) with adhesive; and Group III - adhesive system and vittra APS (FGM) resin. The collected data were submitted to the Anova statistical test in which the comparison between Groups I and II, II and III, and I and III was performed. In none of the cases a significant difference was found (p <0.05). Despite the limitations of an in vitro study, the results suggest that the marginal sealing of composite resin and alkasite do not differ significantly from each other.
OBJECTIVE: Dental care has been particularly concerned with sterilization of instruments and materials. In this context, the methods used for infection control are essential to ensure patients’ safety. This in vitro study aimed to test gingival retraction cords taken from factory- sealed containers for the presence of contamination. Three commercial brands of retraction cords were analyzed: Retraflex®, Pró-Retract®, and Ultrapack®.METHODS: The sample consisted of 10 1-cm segments of retraction cords of each commercial brand (n = 30). For bacterial growth analysis, 30 test tubes containing sterile brain heart infusion (BHI) as the culture medium were used. Bacterial growth was considered positive in tubes in which the BHI broth became turbid.RESULTS: Of 30 test tubes with retraction cords, six showed turbidity and were considered contaminated: three tubes with Retraflex®, one tube with Pro-Retract®, and two tubes with Ultrapack®, accounting for 20% of the total sample.CONCLUSIONS: The present findings showed that some retraction cords received from the manufacturers were contaminated with microorganisms. Thus, extra caution should be taken when using these materials, and further studies should be conducted.
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