RESUMO
STATEMENT OF THE PROBLEM: The effect of the intraoral environment during adhesive restorative procedures remains a concern, especially in the absence of rubber dam isolation. OBJECTIVE: To evaluate the temperature and relative humidity (RH) at anterior and posterior intraoral sites and their effects on the dentin bond strength of two-step etch-and-rinse adhesive systems. METHODS: Sixty human molars were assigned to six groups according to the adhesive systems (Adper Single Bond Plus and One Step Plus) and intraoral sites (incisor and molar sites). The room condition was used as a control group. Dentin fragments were individually placed in custom-made acetate trays and direct composite restorations were performed. The intraoral temperature and RH were recorded during adhesive procedures. Then, specimens were removed from the acetate trays and sectioned to obtain multiple beams for the microtensile bond strength test. In addition, the adhesive interface morphology was evaluated through scanning electron microscopy. Intraoral conditions were statistically analyzed by paired Students' t-tests and the bond strength data by two-way analysis of variance and Tukey test (α = 0.05). RESULTS: The posterior intraoral site showed a significant increase in the temperature and RH when compared with the anterior site. However, both intraoral sites revealed higher temperatures and RH than the room condition. In regards to the adhesive systems, the intraoral environment did not affect the bond strength, and the One Step Plus system showed the highest bond strength means. CONCLUSION: Despite the fact that remarkable changes in the intraoral conditions were observed for both anterior and posterior sites, the intraoral environment was not able to compromise the immediate dentin bond strength. CLINICAL SIGNIFICANCE: Some conditions of intraoral temperature and relative humidity may not impair the dentin bond strength of two-step etch-and-rinse adhesive systems. Thus, an adequate relative isolation seems to be a good alternative under the specific clinical conditions in which rubber dam isolation is either impossible or very difficult to perform.
Assuntos
Colagem Dentária , Dentina/química , Umidade , Teste de Materiais , Temperatura , Resistência à TraçãoRESUMO
STATEMENT OF PROBLEM: The lack of long-term bond stability between resin cements and dentin may compromise the success of indirect restorations. PURPOSE: The purpose of this study was to evaluate the effects of long-term storage in artificial saliva and mechanical load cycling on the microtensile bond strength of conventional and self-adhesive resin cements to dentin. MATERIAL AND METHODS: The occlusal dentin surfaces of 128 human molars were exposed and flattened. The teeth were assigned to 16 groups (n=8) according to resin cement and in vitro aging strategy. Two self-adhesive resin cements (RelyX Unicem and Clearfil SA Cement) and 2 conventional cementing systems (RelyX ARC and Clearfil Esthetic Cement) were used. Resin cements were applied to prepolymerized indirect resin disks, which were bonded to the dentin surfaces and light polymerized. The control groups were represented by immediate microtensile bond strength (24 hours) and aging methods were performed with mechanical load cycling or storage in artificial saliva (1 year and 2 years). Bonded beams were tested in tension until failure. Data (MPa) were analyzed by Proc Mixed for repeated measures and the Tukey-Kramer test (α=.05). RESULTS: The self-adhesive resin cements exhibited higher microtensile bond strength than conventional cementing systems for all conditions studied. The microtensile bond strength of RelyX ARC and self-adhesive resin cements did not decrease after storage in artificial saliva and mechanical load cycling. The Clearfil Esthetic Cement showed the lowest microtensile bond strength and a significant reduction after 2 years of storage in artificial saliva. CONCLUSIONS: The storage times and mechanical load cycling did not affect the microtensile bond strength of self-adhesives and RelyX ARC resin cements. The highest microtensile bond strength was obtained for self-adhesive resin cements, with no significant difference between them.
Assuntos
Colagem Dentária , Dentina/ultraestrutura , Cimentos de Resina/química , Bis-Fenol A-Glicidil Metacrilato/química , Resinas Compostas/química , Análise do Estresse Dentário/instrumentação , Humanos , Cura Luminosa de Adesivos Dentários , Teste de Materiais , Polietilenoglicóis/química , Polimerização , Ácidos Polimetacrílicos/química , Saliva Artificial/química , Estresse Mecânico , Resistência à Tração , Fatores de TempoRESUMO
This study evaluated the bonding compatibility between dual-cured resin cements and simplified adhesive systems (one-step self-etch and two-step etch & rinse), measured after 24 hours and 3 months. The occlusal dentin surfaces of 24 human third molars were exposed and flattened. Teeth were randomly assigned to 3 groups and treated with different combinations of adhesive system and resin cement [G1-Single Bond/Rely X ARC (SB/RX); G2-Excite DSC/Variolink II (EX/VR); G3-Adper Prompt/Rely X ARC (AD/RX)]. Indirect composite restorations were cemented on flattened surfaces, and sectioned to obtain multiple bonded beams for the microtensile bond strength test. The beams from each tooth were tested under tension after 24 hours and 3 months (ANOVA/ Tukey's test, alpha=5%). Failure patterns were evaluated with scanning electron microscopy. After 24h, AD/RX presented the lowest bond strength mean values. AD/RX specimens did not withstand three months storage. SB/RX and EX/VR presented similar bond strengths in both periods tested. The association AD/RX resulted in low bond strength mean values, especially after storage. Cementing indirect restorations using one-step self-etch adhesive systems and dual-cured resin cements would be clinically unreliable.
Assuntos
Teste de Materiais , Cimentos de Resina , Autocura de Resinas Dentárias , Cimentos Dentários , Humanos , Técnicas In Vitro , Fatores de TempoRESUMO
This study evaluated the bonding compatibility between dualcuredresin cements and simplified adhesive systems (one-step self-etch and two-step etch & rinse), measured after 24 hours and 3 months. The occlusal dentin surfaces of 24 human third molars were exposed and flattened. Teeth were randomly assigned to 3 groups and treated with different combinations ofadhesive system and resin cement [G1 - Single Bond/Rely X ARC (SB/RX); G2 - Excite DSC/Variolink II (EX/VR); G3 -Adper Prompt/Rely X ARC (AD/RX)]. Indirect composite restorations were cemented on flattened surfaces, and sectioned to obtain multiple bonded beams for the microtensile bond strength test. The beams from each tooth were tested under tension after 24 hours and 3 months (ANOVA/ Tukeys test, α=5%). Failure patterns were evaluated with scanning electron microscopy. After 24h, AD/RX presented the lowest bond strength mean values. AD/RX specimens did not withstandthree months storage. SB/RX and EX/VR presented similar bond strengths in both periods tested. The associationAD/RX resulted in low bond strength mean values, especially after storage. Cementing indirect restorations using one-step self-etch adhesive systems and dual-cured resin cements wouldbe clinically unreliable.
Este estudo avaliou a compatibilidade de união entre cimentos resinosos de dupla polimerização e sistemas adesivos simplificados (adesivo autocondicionante - 1 passo- e adesivo total-each - 2 passos), após 24h e 3 meses. A superfície oclusal de 24 terceiros molares humanos foi exposta e planificada. Os dentes foram aleatoriamente divididos em 3 grupos usados de acordo a seguinte combinação entre sistema adesivo/cimento resinoso [G1 - Single Bond/Rely X ARC (SB/RX); G2 - Excite DSC/Variolink II (EX/VR); G3-Adper Prompt/Rely X ARC (AD/RX)]. Restaurações indiretas em resina composta foram cimentadas na superfície dentinária, e seccionados em múltiplos palitos para a realização do teste de resistência de união através do ensaio de microtração. Os palitos obtidos por dente foram submetidos ao teste após 24 horas e 3 meses (ANOVA/ Tukey test, α=5%). O padrão de fraturafoi observado no microscópio eletrônico de varredura. Após 24 horas, AD/RX apresentou menor valor médio de resistência de união. Os corpos-de-prova do grupo AD/RX não resistiram aoarmazenamento de 3 meses. SB/RX e EX/VR demonstraram similarresistência de união em ambos os períodos avaliados. A associação AD/RX resultou em menores valores médios deresistência de união, especialmente após o armazenamento. A cimentação de restaurações indiretas utilizando sistemas autocondicionantes (1 passo) e cimentos resinosos de dupla polimerização não foi considerada clinicamente confiável.
Assuntos
Adesivos Dentinários/química , Cimentos de Resina/química , Dentina , Colagem Dentária/métodos , Força Compressiva , Microscopia Eletrônica de Varredura/métodos , Interpretação Estatística de DadosRESUMO
This study evaluated the bonding compatibility between dualcuredresin cements and simplified adhesive systems (one-step self-etch and two-step etch & rinse), measured after 24 hours and 3 months. The occlusal dentin surfaces of 24 human third molars were exposed and flattened. Teeth were randomly assigned to 3 groups and treated with different combinations ofadhesive system and resin cement [G1 - Single Bond/Rely X ARC (SB/RX); G2 - Excite DSC/Variolink II (EX/VR); G3 -Adper Prompt/Rely X ARC (AD/RX)]. Indirect composite restorations were cemented on flattened surfaces, and sectioned to obtain multiple bonded beams for the microtensile bond strength test. The beams from each tooth were tested under tension after 24 hours and 3 months (ANOVA/ Tukeys test, α=5%). Failure patterns were evaluated with scanning electron microscopy. After 24h, AD/RX presented the lowest bond strength mean values. AD/RX specimens did not withstandthree months storage. SB/RX and EX/VR presented similar bond strengths in both periods tested. The associationAD/RX resulted in low bond strength mean values, especially after storage. Cementing indirect restorations using one-step self-etch adhesive systems and dual-cured resin cements wouldbe clinically unreliable.(AU)
Este estudo avaliou a compatibilidade de uniÒo entre cimentos resinosos de dupla polimerizaþÒo e sistemas adesivos simplificados (adesivo autocondicionante - 1 passo- e adesivo total-each - 2 passos), após 24h e 3 meses. A superfície oclusal de 24 terceiros molares humanos foi exposta e planificada. Os dentes foram aleatoriamente divididos em 3 grupos usados de acordo a seguinte combinaþÒo entre sistema adesivo/cimento resinoso [G1 - Single Bond/Rely X ARC (SB/RX); G2 - Excite DSC/Variolink II (EX/VR); G3-Adper Prompt/Rely X ARC (AD/RX)]. Restauraþ§es indiretas em resina composta foram cimentadas na superfície dentinária, e seccionados em múltiplos palitos para a realizaþÒo do teste de resistÛncia de uniÒo através do ensaio de microtraþÒo. Os palitos obtidos por dente foram submetidos ao teste após 24 horas e 3 meses (ANOVA/ Tukey test, α=5%). O padrÒo de fraturafoi observado no microscópio eletr¶nico de varredura. Após 24 horas, AD/RX apresentou menor valor médio de resistÛncia de uniÒo. Os corpos-de-prova do grupo AD/RX nÒo resistiram aoarmazenamento de 3 meses. SB/RX e EX/VR demonstraram similarresistÛncia de uniÒo em ambos os períodos avaliados. A associaþÒo AD/RX resultou em menores valores médios deresistÛncia de uniÒo, especialmente após o armazenamento. A cimentaþÒo de restauraþ§es indiretas utilizando sistemas autocondicionantes (1 passo) e cimentos resinosos de dupla polimerizaþÒo nÒo foi considerada clinicamente confiável.(AU)