Tetrahydrofuran as solvent in dental adhesives: cytotoxicity and dentin bond stability.

OBJECTIVES: The aim of this study was to investigate the cytotoxicity and 1-year dentin bond stability of solvated etch-and-rinse dental adhesives based on tetrahydrofuran (THF), acetone, or ethanol, containing water or not. MATERIALS AND METHODS: Seven primers were prepared using the following solvents: THF, acetone, ethanol, water, THF/water, acetone/water, and ethanol/water. Bovine dentin was used, and specimens for microtensile bond strength (µTBS) test were prepared. Specimens were tested after storage in distilled water for 24 h or 1 year. Cytotoxicity of the solvents was evaluated in 3T3/NIH mouse fibroblasts using a colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after exposure for 24 h. RESULTS: No significant differences were detected among solvents after storage for 24 h, except for the water-based group, which showed the lowest µTBS values. After storage for 1 year, the THF-based adhesive system resulted in more stable bonds. Yet, THF showed an intermediate cytotoxicity when compared with the other solvents, being less toxic than phosphate monomer and similar to 2-hydroxyethyl methacrylate. CONCLUSION: THF seems to be a suitable solvent for adhesive systems. CLINICAL RELEVANCE: THF is a promising solvent that can be used to improve dentin bond stability.

Restabelecendo a estética dos dentes anteriores com clareamento e restaurações em resina composta: relato de caso clínico / Recovering esthetics in anterior teeth with bleaching and composite restorations: case report

A crescente demanda por procedimentos estéticos e tratamentos dentários não-invasivos favoreceu o surgimento de diferentes abordagens para solução de problemas de alteração de cor dentária. Com o desenvolvimento das técnicas de clareamento dental e da odontologia adesiva, é possível oferecer tratamentos conservadores para recuperação de dentes anteriores comprometidos. O presente caso clínico relata a associação de duas técnicas de clareamento para dentes vitais escurecidos e de um compósito restaurador nanoparticulado para restauração de incisivos centrais superiores. Resultados estéticos satisfatórios foram obtidos com a combinação de opções de tratamento minimamente invasivas para restabelecimento da cor e forma dos dentes...

The increasing demand for esthetic, non-invasive dental procedures led to the introduction of a number of approaches to resolve problems from tooth discolorations. The development of tooth bleaching and adhesive techniques made possible to provide conservative treatments to restore compromised anterior teeth. This case report presents the association of two bleaching techniques for vital discolored teeth and the use of a nanofilled composite resin to restore the maxillary central incisors. It was concluded that satisfactory results can be achieved through the association of minimally invasive approaches to reestablish tooth color and shape...

Resin-dentin bond strength of 10 contemporary etch-and-rinse adhesive systems after one year of water storage.

To compare the resin-dentin bond degradation of 10 contemporary etch-and-rinse adhesive systems after one year of water storage, 100 bovine incisors were randomly separated into 10 groups and their superficial coronal dentin was exposed. According to manufacturers' instructions, dentin surfaces were bonded with one of seven two-step etch-and-rinse adhesives or one of three three-step etch-and-rinse adhesives. Composite buildups were constructed incrementally. Restored teeth were sectioned to obtain sticks (0.5 mm²). The specimens were subjected to a microtensile bond strength test after storage in distilled water (at 37°C) for one year. Data (MPa) were analyzed using Kruskal-Wallis and Tukey's tests at α = 0.05. Of the adhesives tested, One Step, All Bond 2, and Optibond FL attained the highest bond strength to dentin after one year in water storage, while Magic Bond DE and Master Bond presented a high number of premature debonded flaws.

Microtensile bond strength of two-step etch-and-rinse adhesive systems on sound and artificial caries-affected dentin.

PURPOSE: To evaluate the microtensile bond strength of two-step etch-and-rinse adhesive systems on sound and artificial caries-affected dentin (CAD) produced by in vitro monoculture of Streptococcus mutans. METHODS: 10 recently extracted non-carious human third molars were ground to expose a flat dentin surface. Each tooth was sectioned through the long axis with a diamond saw to create two similar halves. One half was used as control (sound dentin - SD) while the other was submitted to caries lesion induction in vitro, using 40 mL of Brain Heart Infusion broth containing 1% sucrose and 40 microL of Streptococcus mutans UA159 inoculum (final bacterial concentration: 1-2 x 105 CFU/mL). The specimens were incubated at 37 degrees C for 4 weeks, and the culture medium was changed every 3 days for 4 weeks. Sound or CAD were alternatively restored as follow (n = 5): Single Bond 2/sound dentin (SB-SD); Single Bond 2/artificial caries-affected dentin (SB-CAD); Prime&Bond NT/sound dentin (PB-SD); and Prime&Bond NT/CAD (PB-CAD).The adhesives were applied to dentin according to manufacturers' instructions, and build-ups of resin composite (Filtek Z250) were prepared and polymerized with a LED light-curing unit (Radii). The restored teeth were stored in distilled water at 37 degrees C for 24 hours and thereafter sectioned perpendicular to the bonded interface with a refrigerated low-speed diamond saw, obtaining three slices per half-tooth (n = 15). The microtensile bond strength (microTBS) test was performed in a universal test machine with a crosshead speed of 1 mm/minute. Bond strengths were calculated in MPa and analyzed by Kruskal-Wallis and Student-Newman-Keuls at a 0.05 level of significance. Failure patterns were examined with an optical microscope. RESULTS: SD produced significantly higher microTBS values than CAD for both adhesive systems. Furthermore, independently of the dentin condition, Single Bond 2 had higher values than Prime Bond NT (P < 0.05). Single Bond 2 showed higher microTBS than Prime Bond NT, in both substrates, and application to CAD reduced the adhesion.

Effect of additional acid etching on bond strength and structural reliability of adhesive systems applied to caries-affected dentin .

PURPOSE: To evaluate the effect of additional acid etching on the microtensile bond strength (µTBS) and Weibull modulus (m) of two adhesive systems applied to caries-affected dentin. MATERIALS AND METHODS: Ninety human molars with coronal carious lesions were sectioned to produce flat coronal surfaces containing caries-affected (CAD) and sound dentin (SD). The teeth were allocated to 6 groups: SB-CT: Control - Single Bond applied according to the manufacturer's instructions; SB+15: Single Bond with additional 35% phosphoric acid etching for 15 s; SB+30: Single Bond with additional etching for 30 s; CF-CT: Control - Clearfil SE Bond applied according to the manufacturer's instructions; CF+15: Clearfil SE Bond with additional 35% phosphoric acid etching for 15 s; CF+30: Clearfil SE Bond with additional etching for 30 s. Composite crowns were incrementally built up. The teeth were sectioned after 24 h in order to produce 2 to 3 slices involving each dentin substrate. The slices were trimmed into hourglass-shaped specimens (n = 30) and tested in tension at a crosshead speed of 1 mm/min. Data were analyzed by three-way ANOVA, Tukey's test (p < 0.05) and Weibull statistics. RESULTS: The µTBS to CAD was lower than to SD, except for SB+30. The additional etching increased the µTBS to CAD. The µTBS to SD increased with CF, but decreased with SB. CAD produced lower values of m with both adhesive systems. SB resulted in lower m in sound dentin than CF. The additional etching did not affect the m. CONCLUSION: The additional etching increases the µTBS to CAD, but not enough to reach the µTBS values obtained in SD. The structural reliability of the bond to CAD is not affected by the additional etching.

Restauración semidirecta de resina compuesta: una alternativa para dientes posteriores: reporte de caso clínico / Semi-direct composite resin restoration: an alternative for posterior teeth: case report

Las restauraciones semidirectas de resina compuesta para el tratamiento de dientes posteriores con extensa pérdida de tejido dentario surgieron hace algunos años como una alternativa de tratamiento frente a las restauraciones directas en resina, amalgama y restauraciones cerámicas. Utilizando una técnica que permita la confección extraoral de la restauración, es posible optimizar las condiciones clínicas de trabajo y mejorar las propiedades finales del material restaurador. El presente trabajo tiene por objetivo reportar un caso clínico donde se utilizó una restauración semidirecta de resina compuesta para substituir una restauración defectuosa de amalgama. En este trabajo se describen los procedimientos clínicos realizados y se discuten las ventajas y desventajas asociadas a la técnica utilizada

Semi-direct composite restorations to treat teeth with large tooth loss appeared recently as an alternative to the direct restorations (amalgam and composite) and the ceramic restorations. Using an extraoral technique to produce the restoration will improve the clinical conditions and the mechanical properties. Here, we reported a case where a semi-direct composite restorations was employed to replace a defective large amalgam restoration. The report describes the clinical procedures and discuss the advantages and disadvantages associated to the technique

Frequencia de pinos intrarradiculares utilizados em procedimentos de reconstrução dentária na Faculdade de Odontologia da Universidade Federal de Pelotas / Frequence of posts used in dental reconstruction procedures in the patients assisted at Dentistry School of Federal University of Pelotas

Objetivo: Realizar um levantamento dos pinos intracanais utilizados nos procedimentos de reconstrução dentária, na Faculdade de Odontologia da Universidade Federal de Pelotas, e verificar sua relação com a técnica restauradora e localização no arco dentário. Metodologia: Os prontuários arquivados no Serviço de Triagem, no período entre 2005 e 2008, foram analisados quanto ao tipo de pino intracanal, técnica restauradora e localização no arco dentário. Os dados foram analisados estatisticamente (teste Qui-quadrado), considerando p < 0,05. Resultados: De um total de 5.566 registros, 192 (4,7%) procedimentos restauradores utilizaram os seguintes tipos de retontores: 107 (55.7%) metálicos fundidos, 38 (19,7%) fibra de vidro, 27 (14,1%) metálicos, 14 (7,2%) fibra de carbono e 6 (3,1%) fio de aço. Restaurações indiretas e diretas foram realizadas em 51% e 49% dos casos, respectivamente. Pinos metálicos fundidos foram mais associados a restaurações indiretas (p < 0,001). Considerando a sua localização na arcada, não houve diferença significativa entre os pinos utilizados na região anterior e posterior (p = 0,457).Conclusões: Durante o período de estudo, a maioria dos procedimentos de reconstrução dentária em dentes tratados endodonticamente foram realizados sem utilização de retentores intracanais. Porém, pinos metálicos fundidos foram mais frequentemente associados a coroas unitárias protéticas.

Purpose: To accomplish a rising of posts used in dental reconstruction procedures, at the School of Dentistry of Federal University of Pelotas, and verify it relationship with the restoring technique and location in the dental arch.Methods: The handbooks filed in the Service of Patient Selection, in the period understood between 2005 and 2008, it were appreised as for the post type, recovering technique and location in the dental arch. The data were submitted to the statistical analysis (test Qui-square), considering p<0,05. Results: From the total of 5.566 handbooks filed, 192 (4,7%) recovering procedures were accomplished using the following types of posts: 107 (55,7%) melted metallic, 38 (19,7%) glass fiber, 27 (14,1%) metallic, 14 (7,2%) carbon fiber and 6 (3,1%) posts of steel. Prosthetic crowns (indirects) and direct recovering were accomplished in 51% and 36,9% of the cases, respectively. Melted metallic posts were more associated to indirect restorations (p<0,001) . Considering the position of the tooth in the arcade, there was not statistic significant differences among the types of posts used in the anterior and posterior area (p=0,457). Conclusions: During the period of this study, the majority of recovering procedures of endodontically treated teeth was accomplished without the use of posts. However, melted metallic posts were more associated to indirect restorations.

Fracture resistance of premolars restored with partial ceramic restorations and submitted to two different loading stresses.

This in vitro study evaluated the fracture resistance of teeth restored with different designs of partial ceramic restorations using two diameters of steel ball to apply fracture stresses. One hundred and twenty sound maxillary premolars were randomly divided into three groups of 40 elements; each group was submitted to one of three indirect restoration designs: inlay, onlay with only lingual cuspal coverage and onlay with buccal and palatal cuspal coverage. Another 20 intact teeth were randomly assigned as control groups. The restorations were produced with Super Porcelain EX-3 and Vitadur Alpha ceramics and luted according to manufacturers' instructions. The specimens were subjected to compressive axial loading in a universal testing machine at 0.5 mm/minute using two steel balls (3 and 10 mm in diameter), evaluating a total of 14 groups with 10 specimens each. Peak load to fracture was measured for each specimen. The results were submitted to analysis of variance and Tukey's test. Statistical analysis revealed that the inlays showed a significantly higher fracture resistance than both onlay designs, but with fracture resistance lower than that of intact teeth. Onlay fracture strength was equivalent for both designs. The force required to cause fracture with the 10-mm diameter ball was greater than with the 3-mm diameter ball. There were no differences between the tested ceramics.

Aspectos microbiológicos da cárie dental / Microbiological aspects of dental cavities

A cárie é uma doença infecto-contagiosa, de caráter crônico e multifatorial. Sabe-se da indispensabilidade de microrganismos na superfície dental para que tenhamos o desenvolvimento da doença cárie, porém só a presença deles não é o bastante. Fatores como higiene, hábitos alimentares, colonização bacteriana, composição da saliva, entre outros, influenciam o metabolismo das bactérias sobre os dentes, modulando a atividade da cárie. Até a década de 60, os Lactobacilos eram tidos como os principais agentes etiológicos. Entretanto, quando mais informações sobre a composição microbiana do biofilme foram obtidas, observou-se que os Lactobacilos constituem apenas uma pequena fração de sua composição. Atualmente sabe-se que esses microrganismos são mais uma conseqüência do que causa do processo de iniciação da doença. O S. mutans, após sua redescoberta em 1960 por Fitzgerald e Keyes, tem sido, conforme relata a literatura, apontado como a principal bactéria em relação à etiologia da cárie. Entre as espécies incluídas nos Estreptococos do Grupo Mutans (EGM), o S. mutans e S. sobrinus apresentam potencial cariogênico em humanos. Os trabalhos indicam a diversidade de microrganismos que habitam a superfície dentária, existindo no mínimo quatro diferentes tipos de cáries. Este artigo tempor objetivo, fazer uma revisão sobre os principais aspectos microbiológicos envolvidos com a cárie dental.

Dental caries is an infectious-contagious disease that has a chronic multifactorial pattern. It is known that the presence of microrganisms on dental surface is essential for the development of caries disease, despite only their presence is not e nough. Factors such as hygiene, alimentary habits, bacterial colonisation, and saliva composition, among others, influence the metabolism of bacteria on the teeth, modulating caries activity. Until 1960, Lactobacillus were regarded as the main etiological agents. However, when more information about the microbiological composition of the biofilm was obtained, it was observed that Lactobacillus constitute only a small fraction of its composition. Currently, it is known that these microrganisms are rather a consequence than a cause of the initiating process of the disease. According to literature reports, the S. mutans, after being rediscovered by Fitzgerald e Keyes in 1960, has been pointed out as the main bacteria related to caries etiology. Among the species included in Mutans Streptococci Group (MSG),S. mutans and S. sobrinus have a cariogenic potential in humans. Research indicate the diversity of the microrganisms hosted on dental surface, there being at least four different types of caries. The purpose of this paper is to review the major microbiological aspects involved in dental caries.