Bond strength of two universal adhesive systems to human dentin using different strategies.

The objective of this study was to evaluate the microtensile bond strength (µTBS) to dentin of two universal adhesive systems: Single Bond Universal (SBU) and Ambar Universal (AU), used in different adhesion strategies. MATERIALS AND METHOD: Thirty-six human teeth were prepared (n=6) and treated following different adhesive strategies: G1: SBU-etch-and-rinse, applied on dry dentin; G2: SBUetch- and-rinse, applied on moist dentin; G3: SBU-self-etching; G4: AU-etch-and-rinse, applied on dry dentin; G5: AU-etch-and-rinse, applied on moist dentin; G6: AU-self-etching. The specimens were submitted to µTBS test, failure analysis, and scanning electron microscopy (SEM). Data were analyzed with ANOVA and Tukey's tests (p<0.05). RESULTS: Microtensile bond strength was significantly lower in G1 than G2 and G3. AU adhesive performed worse than the SBU system, except in G5. Cohesive and mixed failures predominated in G1 and G2, while adhesive failures predominated in G3 and G5. CONCLUSIONS: Universal adhesives are an interesting innovation, but there are still doubts about their performance, mainly regarding the different protocols provided by the manufacturers. The conventional adhesive strategy on moist dentin demonstrated higher µTBS for both adhesives. The use of the selfetching strategy with the SBU showed promising results.

O objetivo deste estudo foi avaliar a resistência de união à microtração (µTBS) de dois sistemas adesivos universais: Single Bond Universal (SBU) e Ambar Universal (AU), utilizados em diferentes estratégias de adesão. Materiais e método: 36 dentes humanos foram preparados (n=6) e tratados seguindo diferentes estratégias adesivas: G1: SBU-condicionamento e enxágue, aplicado sobre dentina seca; G2: SBU-condicionamento e enxágue, aplicado sobre dentina úmida; G3: SBU-autocondicionante; G4: AU-condicionamento e enxágue, aplicado em dentina seca; G5: AU-condicionamento e enxágue, aplicado sobre dentina úmida; G6: AU-autocondicionante. Os espécimes foram submetidos ao teste de µTBS, análise de falhas e microscopia eletrônica de varredura (SEM). Os dados foram analisados com os testes ANOVA e Tukey (p<0,05). Resultados: A resistência de união à microtração de G1 foi significativamente menor que G2 e G3. O adesivo AU teve um desempenho pior que o sistema SBU, com exceção do G5. Falhas coesivas e mistas predominaram em G1 e G2 enquanto G3 e G5 apresentaram predominância de falhas adesivas. Conclusões: Os adesivos universais representam uma inovação interessante, mas ainda há dúvidas sobre seu desempenho, principalmente em relação aos diferentes protocolos fornecidos pelos fabricantes. A estratégia adesiva convencional em dentina úmida demonstrou maior µTBS para ambos os adesivos. O uso da estratégia autocondicionante com a SBU apresentou resultados promissores.

Analysis of camphorquinone in composite resins as a function of shade.

OBJECTIVE: To identify and quantify the camphorquinone (CQ) used in different brands of composite resins as a function of the shade analyzed. MATERIALS AND METHODS: Filtek Z250 A3 (FZA3), Filtek Z-250 Incisal (FZI), Pyramid Enamel A1 (PEA1), Pyramid Enamel Translucent (PET), Filtek Supreme A3E (FSA3) and Filtek Supreme GT (FSGT) were used. Five hundred milligrams of each resin were weighed and then dissolved in 1.0 ml of methanol. The samples were centrifuged to accelerate the sedimentation of the inorganic particles. 0.8 ml of the supernatant solution was collected with a pipette and assessed under gas chromatography coupled to the mass spectrometer (GC-MS). The results were compared to pure CQ solutions, used as a standard. Student's t-test, (p=0.05) significant at the level of 5%, compared the results of each brand shade. RESULTS: A smaller amount of camphorquinone was found in Filtek Z-250 (FZI) resin incisal shade when compared to (FZA3) A3 shade. On the other hand, Filtek Supreme resin featured a statistically larger camphorquinone amount in the incisal shade. In Pyramid Enamel resin camphorquinone was found only in shade A1, while the photoinitiator used in the Translucent shade was not identified. SIGNIFICANCE: Based on the data obtained, it is possible to conclude that a single composite resin brand may feature differences in amount and type of photoinitiator used.

Effects of surface treatment on the microtensile bond strength of ceramic materials to dentin.

This study evaluated the effects of distinct surface treatments on the micro-tensile bonding strength (microTBS) of different ceramic materials. The occlusal surfaces of eighteen human maxillary molars were flattened perpendicularly to the long axis and divided in groups based on surface treatment (sandblasting: s; hydrofluoric acid: a; tribochemical silica coating: t): DP-s, DP-a, DP-t, IE-s, IE-a, IE-t, IC-s, IC-a, IC-t) and ceramic materials (Duceran Plus: DP, IPS Empress 2: IE, In-Ceram Alumina, IC). Panavia F luting resins were used according to the manufacturers' instructions to bond ceramic materials to the exposed dentin specimens under a load of 7.5 N. After 3-day storage, microTBS was tested at a cross-head speed of 1 mm/min. Data were analyzed with ANOVA and Tukey's test. ANOVA results showed that the microTBS of DP and IC were significantly different. The microTBS of DP-a was significantly higher than those of DP-s and DP-t. The microTBS of IC-t was significantly higher than those of IC-s and IC-a. Ceramic materials with different chemical formulations and applications yielded significantly different bond strengths to human dentin and must receive distinct surface treatments accordingly.

Bond strength of two universal adhesive systems to human dentin using different strategies / Resistência de união de sistemas adesivos universais à dentina humana usando diferentes estratégias

ABSTRACT The objective of this study was to evaluate the microtensile bond strength (μTBS) to dentin of two universal adhesive systems: Single Bond Universal (SBU) and Ambar Universal , used in different adhesion strategies. Materials and Method: Thirty-six human teeth were prepared (n=6) and treated following different adhesive strategies: G1: SBU-etch-and-rinse, applied on dry dentin; G2: SBUetch- and-rinse, applied on moist dentin; G3: SBU-self-etching; G4: AU-etch-and-rinse, applied on dry dentin; G5: AU-etch-and-rinse, applied on moist dentin; G6: AU-self-etching. The specimens were submitted to μTBS test, failure analysis, and scanning electron microscopy (SEM). Data were analyzed with ANOVA and Tukey's tests (p<0.05). Results: Microtensile bond strength was significantly lower in G1 than G2 and G3. AU adhesive performed worse than the SBU system, except in G5. Cohesive and mixed failures predominated in G1 and G2, while adhesive failures predominated in G3 and G5. Conclusions: Universal adhesives are an interesting innovation, but there are still doubts about their performance, mainly regarding the different protocols provided by the manufacturers. The conventional adhesive strategy on moist dentin demonstrated higher μTBS for both adhesives. The use of the selfetching strategy with the SBU showed promising results.

RESUMO O objetivo deste estudo foi avaliar a resistência de união à microtração (μTBS) de dois sistemas adesivos universais: Single Bond Universal (SBU) e Ambar Universal , utilizados em diferentes estratégias de adesão. Materiais e método: 36 dentes humanos foram preparados (n=6) e tratados seguindo diferentes estratégias adesivas: G1: SBU-condicionamento e enxágue, aplicado sobre dentina seca; G2: SBU-condicionamento e enxágue, aplicado sobre dentina úmida; G3: SBU-autocondicionante; G4: AU-condicionamento e enxágue, aplicado em dentina seca; G5: AU-condicionamento e enxágue, aplicado sobre dentina úmida; G6: AU-autocondicionante. Os espécimes foram submetidos ao teste de μTBS, análise de falhas e microscopia eletrônica de varredura (SEM). Os dados foram analisados com os testes ANOVA e Tukey (p<0,05). Resultados: A resistência de união à microtração de G1 foi significativamente menor que G2 e G3. O adesivo AU teve um desempenho pior que o sistema SBU, com exceção do G5. Falhas coesivas e mistas predominaram em G1 e G2 enquanto G3 e G5 apresentaram predominância de falhas adesivas. Conclusões: Os adesivos universais representam uma inovação interessante, mas ainda há dúvidas sobre seu desempenho, principalmente em relação aos diferentes protocolos fornecidos pelos fabricantes. A estratégia adesiva convencional em dentina úmida demonstrou maior μTBS para ambos os adesivos. O uso da estratégia autocondicionante com a SBU apresentou resultados promissores.

Influence of different light sources on the conversion of composite resins.

AIMS: The purpose of this paper was to evaluate the influence of different light curing units on the conversion of four composite resins with different compositions (Durafill VS - Heraeus-Kulzer, Tetric Ceram - Ivoclar/Vivadent, Filtek Supreme XT - 3M ESPE e Aelite LS Packable - Bisco), using differential scanning calorimetry. MATERIALS AND METHODS: A stainless steel matrix was used to prepare 48 cylindrical composite test samples (n=6), measuring 3 mm in diameter and 1 mm in thickness. The samples were photoactivated using a halogen lamp (Optilux 500 - Demetron/Kerr) and three different generations of light-emitting diodes (LEDs) (LEC-470 I - MMOptics, Radii Plus - SDI and Ultra-Lume LED 5 - Ultradent). After removal of the matrix, each sample was weighed and hermetically sealed in an aluminum pan and analyzed. The amount of heat liberated by thermopolymerisation of residual monomers after photoactivation was measured in Joules/gram (J/g). The data were submitted to Analysis of Variance (ANOVA) test (P ≤ 0.002) and the Tukey test (P < 0.05). RESULTS: The Ultra-Lume LED 5 was superior on degree of conversion for all resins. The Radii Plus was equal to the Ultra-Lume LED 5, except for the resin Tetric Ceram , were the Optilux 500 was superior. The LEC-470 I was inferior for the conversion of all resins. CONCLUSION: The study proves the importance of the compatibility of the different photoinitiators in resin composites with the different light sources.

Effect of hydrogen peroxide topical application on the enamel and composite resin surfaces and interface.

OBJECTIVES: The objective of the present study was to analyze the superficial roughness and the interface between enamel and composite resin restorations after dental bleaching procedure. MATERIALS AND METHODS: Black's class V cavities were made and restored with composite resin, and the whole set, enamel-restorative material, was treated with 35% hydrogen peroxide. Seven procedures of 30 min each were performed. A profilometric assessment was carried out before and after the treatment of each sample, and roughness scores were obtained. Treated and untreated samples were analyzed under scanning electronic microscope and images of their surface were obtained. RESULTS AND CONCLUSION: The treatment with 35% hydrogen peroxide caused no alteration in the interface between enamel and composite resin, Tetric Ceram, fillings and the topical application of 35% hydrogen peroxide on enamel and composite resin, Tetric Ceram, caused an alteration of their surface topography, featuring a predominance of depressions after the bleaching treatment.