ABSTRACT
STATEMENT OF PROBLEM: Dentin surface contamination before the cementation of indirect restorations may impact bonding effectiveness. PURPOSE: The purpose of this in vitro study was to analyze the influence of immediate dentin sealing (IDS) and interim cementation on the adhesion of indirect restorations with a dual-polymerizing resin cement. MATERIAL AND METHODS: Composite resin inlays were placed in class V cavities prepared in the buccal and lingual surfaces of 30 extracted human molars with a dual-polymerizing resin cement in 3 different ways (n=10): CG, directly on dentin; PG, after 14 days interim cementation; SG, after IDS and 14 days interim cementation. Buccal restorations were sectioned into sticks and submitted to the microtensile bond strength (µTBS) test. Lingual restorations were submitted to micro-Raman spectroscopy (MRS). Data were analyzed with 1-way ANOVA and the Tukey-Kramer post hoc test (α=.05). RESULTS: Significantly higher µTBS results were found for SG (35.7 ±8.2 MPa) when compared with CG (23.1 ±7.1 MPa) and PG (17.0 ±6.0 MPa) (P<.05), but no differences were observed between CG and PG. MRS showed that the diffusion zone in SG (3.7 ±0.5 µm) was significantly thicker than that of CG (1.8 ±1.2 µm) or PG (1.5 ±0.3 µm) (P<.05). Additionally, a new interface peak (at approximately 1330 cm-1) was found in SG, indicating a chemical interaction. CONCLUSIONS: The use of IDS before cementation resulted in a chemical interaction at the interface and significantly higher µTBS and diffusion zone thickness values. Interim cementation did not interfere with adhesion quality when compared with the control group.
Subject(s)
Cementation , Dental Bonding , Inlays , Resin Cements , Adhesiveness , Humans , In Vitro Techniques , Surface Properties , Time FactorsABSTRACT
The purpose of this study was to provide the physicochemical interactions at the interfaces between two commercial etch-&-rinse adhesives and human dentin in a simulated moist bond technique. Six dentin specimens were divided into two groups (n=3) according to the use of two different adhesive systems: (a) 2-hydroxyethylmethacrylate (HEMA) and 4-methacryloxyethyl trimellitate anhydrate (4-META), and (b) HEMA. The Fourier transform infrared photoacoustic spectroscopy was performed before and after dentin treatment with 37% phosphoric acid, with adhesive systems and also for the adhesive systems alone. Acid-conditioning resulted in a decalcification pattern. Adhesive treated spectra subtraction suggested the occurrence of chemical bonding to dentin expressed through modifications of the OH stretching peak (3340 cm(-1)) and symmetric CH stretching (2900 cm(-1)) for both adhesives spectra; a decrease of orthophosphate absorption band (1040 to 970 cm(-1)) for adhesive A and a better resolved complex band formation (1270 to 970 cm(-1)) for adhesive B were observed. These results suggested the occurrence of chemical bonding between sound human dentin and etch-&-rinse adhesives through a clinical typical condition.
