Resin bonding to dentine after casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) treatments

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has the ability to enhance enamel and dentine remineralisation and thus has been incorporated in new medicaments for such clinical problems as tooth hypersensitivity and early carious lesions. The current study investigated whether the application of CPP-ACP in the proprietary paste, Tooth Mousse™, would influence the subsequent resin adhesion to dentine. Bonding effectiveness was assessed by microtensile bond strength test and scanning electron microscopy. A three-step etch-and-rinse adhesive (OptiBond FL) or a two-step self-etch adhesive (Clearfil SE Bond) was bonded to three groups of dentine surfaces: no treatment; 5 min or 5 days CPP-ACP application. The microtensile test was performed and bond strength data were analysed using ANOVA and Tukey-Kramer post hoc test. Etching characteristics on respective dentine surfaces and resin-dentine interface were observed under SEM. Bond strengths of Clearfil SE Bond to dentine appeared to be similar for all tested groups. OptiBond FL, however, showed lower bond strengths following the application of CPP-ACP for both time periods. Under SEM observations, the CPP-ACP treated dentine displayed a layer of residue or precipitate attached to the surface after the phosphoric acid treatment. The sectioned specimens also showed the resin-dentine interface with less intertubular linking of resin tags, which could mean mineralisation of these channels, hence preventing resin infiltration. The presence of CPP-ACP on the dentine surface, therefore, may compromise bonding effectiveness of etch-and-rinse adhesive system. However, CPP-ACP application may be beneficial to the dentine bonding of self-etch adhesive system, as the chemical interactions between calcium and functional monomers of the adhesives might be enhanced to some degree. © 2009 VSP.link_to_subscribed_fulltex

Resin adhesion to caries-affected dentine after different removal methods

Background: Caries-affected dentine is the common bonding substrate when treating a patient. At present, there are many methods used for caries removal. The aim of this study was to evaluate the microtensile bond strength of two adhesives (Clearfil Protect Bond and OptiBond Solo Plus Total-Etch) to caries-affected dentine after three different caries removal methods. Methods: Extracted carious human third molars were used and caries-affected dentine surfaces were obtained from one of the three removal methods: (i) round steel bur in a slow-speed handpiece; (ii) Er:YAG laser; or (iii) 600-grit silicon carbide abrasive paper. Each of the adhesives was used to bond resin composite to the caries-affected dentine according to the manufacturers' instructions. Hourglass-shaped specimens were prepared and stressed in tension at 1mm/min. Data were analysed using two-way analysis of variance and least significant difference test. Results: Clearfil Protect Bond showed significantly lower bond strength than OptiBond Solo Plus Total-Etch after caries removal with round steel bur, but the opposite was found for specimens treated with silicon carbide abrasive paper. For laser-treated dentine, no significant differences between the adhesives were revealed. Conclusions: Besides the differences in adhesives, different caries removal methods seem to influence resin adhesion to caries-affected dentine.link_to_subscribed_fulltex

Resin bonding to dentine after casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) treatments

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has the ability to enhance enamel and dentine remineralisation and thus has been incorporated in new medicaments for such clinical problems as tooth hypersensitivity and early carious lesions. The current study investigated whether the application of CPP-ACP in the proprietary paste, Tooth Mousse™, would influence the subsequent resin adhesion to dentine. Bonding effectiveness was assessed by microtensile bond strength test and scanning electron microscopy. A three-step etch-and-rinse adhesive (OptiBond FL) or a two-step self-etch adhesive (Clearfil SE Bond) was bonded to three groups of dentine surfaces: no treatment; 5 min or 5 days CPP-ACP application. The microtensile test was performed and bond strength data were analysed using ANOVA and Tukey-Kramer post hoc test. Etching characteristics on respective dentine surfaces and resin-dentine interface were observed under SEM. Bond strengths of Clearfil SE Bond to dentine appeared to be similar for all tested groups. OptiBond FL, however, showed lower bond strengths following the application of CPP-ACP for both time periods. Under SEM observations, the CPP-ACP treated dentine displayed a layer of residue or precipitate attached to the surface after the phosphoric acid treatment. The sectioned specimens also showed the resin-dentine interface with less intertubular linking of resin tags, which could mean mineralisation of these channels, hence preventing resin infiltration. The presence of CPP-ACP on the dentine surface, therefore, may compromise bonding effectiveness of etch-and-rinse adhesive system. However, CPP-ACP application may be beneficial to the dentine bonding of self-etch adhesive system, as the chemical interactions between calcium and functional monomers of the adhesives might be enhanced to some degree. © 2009 VSP.link_to_subscribed_fulltex

Bond strength of resin modified glass ionomer cement to primary dentin after cutting with different bur types and dentin conditioning

The aim of this in vitro study was to evaluate the effect of different bur types and acid etching protocols on the shear bond strength (SBS) of a resin modified glass ionomer cement (RM-GIC) to primary dentin. Forty-eight clinically sound human primary molars were selected and randomly assigned to four groups (n=12). In G1, the lingual surface of the teeth was cut with a carbide bur until a 2.0-mm-diameter dentin area was exposed, followed by the application of RM-GIC (Vitremer - 3M/ESPE) prepared according to the manufacturer's instructions. The specimens of G2, received the same treatment of G1, however the dentin was conditioned with phosphoric acid. In groups G3 and G4 the same procedures of G1 and G2 were conducted respectively, nevertheless dentin cutting was made with a diamond bur. The specimens were stored in distilled water at 37ºC for 24h, and then tested in a universal testing machine. SBS. data were submitted to 2-way ANOVA (= 5%) and indicated that SBS values of RM-GIC bonded to primary dentin cut with different burs were not statistically different, but the specimens that were conditioned with phosphoric acid presented SBS values significantly higher that those without conditioning. To observe micromorphologic characteristics of the effects of dentin surface cut by diamond or carbide rotary instruments and conditioners treatment, some specimens were examined by scanning electron microscopy. Smear layer was present in all specimens regardless of the type of rotary instrument used for dentin cutting, and specimens etched with phosphoric acid presented more effective removal of smear layer. It was concluded that SBS of a RM-GIC to primary dentin was affected by the acid conditioning but the bur type had no influence