Marginal adaptation of indirect restorations using different resin coating protocols.

This study evaluated the influence of material combinations used in the resin coating technique (RCT) on the marginal adaptation of indirect restorations with gingival margins in enamel (EM) and cement (CM). Eighty third-molars were used. Two cavities were prepared in each tooth. The cavities were distributed into 16 groups. Cavities with EM were filled with the following material combinations: G1: Single-Bond 2 (Sb2), G2: Sb2 + Bond/Scotchbond-Multipurpose (Sb2B), G3: Sb2 + Filtek-Flow Z350 (Sb2Fl), G4: Scotchbond-Multipurpose (SBMP), G5: Clearfil-S3 (CS3), G6: CS3 + Bond/Clearfil-SE Bond (CSE3B), G7: CS3 + Protect Liner F (CS3PL) and G8: Clearfil SE Bond + Protect Liner F (CSEBPL). The same combinations were applied to the cavities in CM: G9, G10, G11, G12, G13, G14, G15, G16, respectively. The fillings were performed with the Sinfony-System (3M/ESPE). After 24 h, the teeth were submitted to thermocycling (2,000 cycles, 5° to 55°C) and load-cycling (50,000 cycles, 50 N). Next, the Caries-Detector (Kuraray) was applied to the restoration margins. Images from the proximal margin were evaluated using the Image-Tool 3.0 software. The results were submitted to ANOVA and Tukey's test (α=0.05). The mean values (%) for the groups were: EM: G1=46.68, G2=15.53, G3=19.83, G4=27.53; G5=59.49, G6=25.13, G7=34.37, G8=15.20; CM: G9=38.38, G10=23.25, G11=26.97, G12=25.85, G13=37.81, G14=30.62, G15=29.17, G16=20.31. The highest percentages of marginal gap on EM or CM were found in the groups that did not use a liner. It can be concluded that the most appropriate RCT combinations were the groups that used a liner.

Microtensile bond strength of indirect composite restorations using different combinations of resin-coating technique / Resistência da união por microtração de restaurações indiretas de resina, usando diferentes combinações na técnica de Resin-Coating

The aim of this study was to evaluate microtensile bond strength (μ-TBS) and failure mode of indirect composite restorations bonded to dentin using different combinations of Resin-Coating (RC) after thermal and load cycling. Thirty five extracted third molars were used in the study. Two box-like Class II cavities were prepared in each tooth (mesial and distal surface). The 70 cavities were distributed in 7 groups according to the coating materials: G1:Etch-rinse 2steps (SB2); G2:Etch-rinse 2steps/Hydrophobic-monomer (SB2/B); G3:Etch-rinse 2steps/Flowable composite resin (SB2/FL); G4:Self-etch 1step (CS3); G5:Self-etch 1step/Hydrophobic monomer (CS3/B); G6:Self-etch1step/Flowable composite resin liner (CS3/PL), G7:Self-etch 2step/Flowable composite resin liner (CSEB/PL). The cavities were molded with a vinyl polysiloxane impression material and the molds were poured with a stone plaster. The fillings were confectioned using the Sinfony composite system (3M/ESPE) and were cemented with resin luting cement (Rely X ARC system). After 24 hours, the teeth were submitted to thermocycling (2,000C/5-55°C) and load cycling (250,000C/30N). After, the restored teeth were sectioned in to beams and μ-TBS were measured. The data were analyzed with ANOVA and Tukey test (p<0.05). In addition failure mode pattern was determined by scanning electrical microscopy. Bond strength were significantly higher in the groups CSEB/PL and CS3/B (p<0.05). In the groups in which was not used a liner, the failure mode exhibited dentin exposure. The groups CSEB/PL and CS3/B showed the highest values of bond strength and the failure mode reveal CSEB/PL exhibited better performance since doesn’t present any fracture kind A.

O objetivo deste estudo foi avaliar a resistência da união, por microtração (μ-TBS), e o modo de fratura de restaurações indiretas de resina aderidas à dentina por diferentes combinações na técnica de Resin-Coating (RC), após ciclagem térmica e mecânica. Neste trabalho foram utilizados trinta e cinco terceiros molares extraídos. Em cada dente foram preparadas duas caixas Classe II (nas faces mesial e distal). As 70 cavidades foram divididas em 7 grupos, de acordo com os materiais de cobertura: G1: adesivo convencional de 2 passos (SB2); G2: adesivo convencional de 2 passos/monômero hidrófobo (SB2/B); G3: adesivo convencional de 2 passos /resina composta flow (SB2/FL); G4:adesivo auto-condicionante de 1 passo (CS3); G5: adesivo auto-condicionante de 1 passo/monômero hidrófobo (CS3/B); G6: adesivo auto-condicionante de 1 passo/resina composta flow forradora (CS3/PL), G7: adesivo auto-condicionante de 2 passos/resina composta flow forradora (CSEB/PL). As cavidades foram moldadas por materiais à base de polivinilsiloxano e os modelos foram obtidos em gesso pedra especial. As restaurações foram confeccionadas usando o sistema Sinfony de compósitos (3M/ESPE); e foram cimentadas com cimento resinoso (Rely X ARC system). Após 24 h, os dentes foram submetidos a ciclagem térmica (2.000C/ 5-55oC) e mecânica (250.000/30N). Foram então seccionadas em palitos para medidas de μ-TBS. Os dados foram analisados por ANOVA e teste Tukey (p<0,05). Além disso, os padrões de fratura foram determinados por meio de microscopia eletrônica de varredura. A resistência da união foi significativamente mais alta nos grupos CSEB/PL e CS3/B (p<0.05). Nos grupos onde não foi usado um agente forrador, os padrões de fratura exibiram exposição de dentina. Os grupos CSEB/PL and CS3/Bos maiores valores de resistência de união e o modo de fratura revelou que CSEB/PL exibiu melhor performance, considerando o fato de não apresentarem nenhuma fratura Tipo A.

Marginal adaptation of indirect restorations using different resin coating protocols

This study evaluated the influence of material combinations used in the resin coating technique (RCT) on the marginal adaptation of indirect restorations with gingival margins in enamel (EM) and cement (CM). Eighty third-molars were used. Two cavities were prepared in each tooth. The cavities were distributed into 16 groups. Cavities with EM were filled with the following material combinations: G1: Single-Bond 2 (Sb2), G2: Sb2 + Bond/Scotchbond-Multipurpose (Sb2B), G3: Sb2 + Filtek-Flow Z350 (Sb2Fl), G4: Scotchbond-Multipurpose (SBMP), G5: Clearfil-S3 (CS3), G6: CS3 + Bond/Clearfil-SE Bond (CSE3B), G7: CS3 + Protect Liner F (CS3PL) and G8: Clearfil SE Bond + Protect Liner F (CSEBPL). The same combinations were applied to the cavities in CM: G9, G10, G11, G12, G13, G14, G15, G16, respectively. The fillings were performed with the Sinfony-System (3M/ESPE). After 24 h, the teeth were submitted to thermocycling (2,000 cycles, 5° to 55°C) and load-cycling (50,000 cycles, 50 N). Next, the Caries-Detector (Kuraray) was applied to the restoration margins. Images from the proximal margin were evaluated using the Image-Tool 3.0 software. The results were submitted to ANOVA and Tukey's test (α=0.05). The mean values (%) for the groups were: EM: G1=46.68, G2=15.53, G3=19.83, G4=27.53; G5=59.49, G6=25.13, G7=34.37, G8=15.20; CM: G9=38.38, G10=23.25, G11=26.97, G12=25.85, G13=37.81, G14=30.62, G15=29.17, G16=20.31. The highest percentages of marginal gap on EM or CM were found in the groups that did not use a liner. It can be concluded that the most appropriate RCT combinations were the groups that used a liner.

Este estudo avaliou a influência de diferentes combinações de materiais usados na técnica de selamento dentinário (TSD) sobre a adaptação marginal de restaurações indiretas, cujas margens gengivais localizam-se em esmalte (ME) ou cemento (MC). Oitenta terceiros molares foram selecionados e duas cavidades foram preparadas em cada dente, as quais foram distribuídas em 16 grupos. As cavidades com margem em esmalte foram forradas pelas seguintes combinações de materiais: G1: Single-Bond2 (Sb2), G2: Sb2 + Bond/Scotchbond-Multipurpose (Sb2B), G3: Sb2 + Filtek-Flow Z350 (Sb2Fl), G4: Scotchbond-Multipurpose (SBMP), G5: Clearfil-S3 (CS3), G6: CS3 + Bond/Clearfil-SE Bond (CSE3B), G7: CS3 + Protect Liner F (CS3PL), G8: Clearfil SE Bond + Protect Liner F (CSEBPL). As mesmas combinações foram aplicadas às cavidades com margens em cemento: G9, G10, G11, G12, G13, G14, G15, G16, respectivamente. As restaurações foram confeccionadas usando o sistema Sinfony (3M/ESPE). Após 24 h, os dentes restaurados foram submetidos à ciclagem térmica (2.000 ciclos - 5° a 55° C) e mecânica (50.000 ciclos, 50 N). Em seguida, Carie-Detector (Kuraray) foi aplicado sobre as margens das restaurações. As imagens obtidas da margem proximal foram avaliadas pelo software Image-Tool 3.0. Os resultados foram submetidos aos testes estatísticos ANOVA e Tukey (p<0,05). As médias (%) observadas para os grupos foram: ME: G1=46,68, G2=15,53, G3=19,83, G4=27,53; G5=59,49, G6=25,13, G7=34,37 e G8=15,20; MC: G9=38,38, G10=23,25, G11=26,97, G12=25,85, G13=37,81, G14=30,62, G15=29,17, G16=20,31. Os maiores valores de desadaptação marginal encontrados em ME e MC foram encontrados nos grupos que não utilizaram um "liner". Desta forma, pôde-se concluir que a combinação mais apropriada para a TSD é aquela que faz uso do "liner".

Effect of resin coat technique on bond strength of indirect restorations after thermal and load cycling.

OBJECTIVE: To evaluate the ability of the resin-coat technique used in cavity preparation to protect dentin before impression taking and final cementation and its effect on the tensile bond strength of indirect restorations after thermal and load cycling. METHODS: Occlusal enamel was removed from 25 third molars to expose flat dentin. Teeth were divided into 5 groups (n=5): G1, receiving no dentin sealing (control group); G2, dentin was hybridized with all-in-one self-etch adhesive (Clearfil S3); G3, receiving combination of a one-step self-etch adhesive and low viscosity resin (Clearfil Protect Liner); G4, dentin was hybridized with "two-step" self-etch adhesive (Clearfil SE Bond); and G5, combination of a "two-step" adhesive system and low viscosity resin was applied. After dentin sealing, indirect restorations were performed with Sinfony system and cementation with dual-cure resin cement (Panavia F). Restored teeth were submitted to thermal (1,500 cycles) and mechanical cycling (200,000 cycles). After this they were sectioned into sticks (1×1 mm, approximately) and then subjected to microtensile bond strength testing. RESULTS: all data were submitted to ANOVA and Tukey test (p<0.05). Mean values (MPa) obtained were G1, 9.5; G2, 9.2; G3, 14.8; G4, 12.2; and G5, 17.4. Statistical analysis showed differences between groups, with G5 performance being higher than that of the other groups. CONCLUSION: when no resin coating-technique was used to protect dentin, lower bond strength values were obtained than those in the other groups. The combination of a "two-step" self-etch adhesive system and low viscosity resin promoted the best bond strength values.

Effectiveness of second-generation light-emitting diode (LED) light curing units.

AIM: The purpose of this study was to evaluate the effectiveness of three commercially available light emitting diode (LED) light curing units (LCU) (Elipar FreeLight--3M ESPE; UltraLume LED2--Ultradent; and Single V--BioArt) for polymerizing Z250-A3 composite (3M ESPE) using Knoop hardness, polymerization depth, and flexural strength properties. METHODS AND MATERIALS: The XL 2500 (3M ESPE) LCU, which is a conventional halogen unit, was used as a control. In all cases the curing time was 20 seconds. Hardness was determined 24 hours after composite cure for 10 samples of 8 mm diameter and 2 mm height for each LCU tested. Samples were stored dry in a light-proof container prior to testing. The depth of cure of the composite was measured immediately after composite polymerization for each LCU using three samples 4 mm in diameter and 6 mm in height. Flexural strength was determined for five samples 24 hours after immersion in distilled water at 37 degrees C. Each sample measured 25 mm in length, 2 mm in width, and 2 mm in height for each LCU tested. CONCLUSION: The results were treated statistically for comparison of the LCUs. In all cases the results obtained by LED LCUs were not different or were higher than a conventional halogen LCU. CLINICAL SIGNIFICANCE: Second generation LED LCUs were as effective as/or more effective than a halogen LCU for polymerization of the used composite. The present study shows second generation LEDs have the potential to replace halogen LCUs.