PubMed · 12524839
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G Helvey. 2000. Prehybridization: an alternative method for dentin bonding.. https://pubmed.ncbi.nlm.nih.gov/12524839/
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This study evaluated the shear bond strength of porcelain/composite using 40 metal + porcelain + composite cylindrical specimens divided into 4 groups, according to porcelain surface treatment: 1) no treatment, 2) mechanical retentions performed with diamond burs, 3) etching with phosphoric acid+silane, and 4) etching with hydrofluoric acid+silane. After being stored in distilled water at room temperature for one week, the specimens were submitted to a shear force (load) and the data were analyzed statistically (ANOVA). The means (in Mpa) of the groups were: 4.71 (group 1); 4.81 (group 2); 11.76 (group 3); 11.07 (group 4). There were no statistically significant differences between groups 1 and 2 and between groups 3 and 4.
The aim of the study was the morphological analysis of coronal dentin caries and the modifications induced by different pretreatments with phosphoric acid or sodium hypochlorite. Carious dentin specimens were obtained from human molars affected by carious lesions. Specimens were divided in four groups and submitted to: (1) untreated; (2) 35% phosphoric acid for 15 s; (3) 35% phosphoric acid for 15 s and 5% sodium hypochlorite for 2 min; (4) sodium hypochlorite for 5 min. Specimens were observed under high-resolution SEM. Different areas were identified within the carious lesion: a deeper, inner region revealing closed highly mineralized tubules, and a more superficial outer layer showing an increasing demineralization rate toward the surface of the lesion. Phosphoric acid followed by NaOCl treatment removed all collagen fibrils from greatly altered carious outer-dentin layer. The 5-min treatment with sodium hypochlorite affected both inner and outer dentin, removing all collagen fibrils and increasing the porosities of deeper intertubular hypermineralized dentin. FEISEM analysis confirmed that only inner carious dentin after phosphoric acid treatment may be considered a suitable substrate for dentinal bonding system. On the contrary, the outer dentin is an unstable substrate for any type of bonding systems and must be avoided/removed from any surface before conditioner application.
The purpose of the study was to evaluate the marginal leakage of three adhesive systems in Class V resin composite restorations. Two adhesive systems containing acidic primers: Clearfil SE Bond (CSEB) and Etch & Prime 3.0 (E&P), were compared with a conventional water-based primer: Scotchbond Multipurpose Plus (SBMP). Class V cavities were made at the cementum-enamel junction of extracted human molars, which were then divided between three groups. One of the adhesive systems was applied to each group following manufacturers' instructions. Composite restorations were placed, light cured for 40 s, and polished. Specimens were then immersed in a solution of 2% basic fuchsin dye for 24 h. Longitudinal sections were obtained and studied with a stereomicroscope for assessment of the microleakage according to the degree of dye penetration (scale of 0-3). Data were analyzed by Kruskal-Wallis one-way ANOVA, Mann-Whitney tests, and the Wilcoxon matched-pairs signed rank test. Two specimens for each group were analyzed by scanning-electron microscopy (SEM). Bonded interfaces of dentin were also examined by transmission-electron microscopy (TEM). On enamel, there were no significant differences between the three groups. On dentin, CSEB showed the lowest dye penetration values among the three adhesive systems. SEM and TEM studies showed hybrid layer and resin tag formations in all groups.