Shear Bond Strength of Three Adhesives to Enamel and Dentin

Bonding agents have evolved from total etch to two bottle and finally one bottle self etching systems.  These newly developed systems may not bond as well to enamel or dentin as total etch materials.  OBJECTIVES: To measure and compare the shear bond strength of three adhesives to enamel and dentin. METHODS: 60 extracted, intact, human molars were divided into two groups and wet ground with a series of abrasives ending with 600 grit to obtain flat enamel (E) and dentin (D) surfaces. The materials used were Adper Scotchbond SE (3M ESPE) a two component self etching adhesive, Adper Easy Bond (3M ESPE) a single component self etching adhesive and Adper Single Bond Plus (3M ESPE) a total etch one bottle adhesive. The adhesives were applied to the bonding area according to manufacturer's instructions. A plastic tube (diameter~1.5mm) filled with composite-resin (Z100) was placed over the adhesive and cured for 40 seconds with a curing light (Fusion, output >800 Mw/cm²). Samples (n=10) were stored in water for 24 hours at 37°C in an incubator before testing. Specimens were placed in a special fixture mounted on a Universal testing machine (INSTRON, model number 5565) and loaded to failure at a crosshead speed of 1mm/min. The failure load was converted to bond strength by dividing by the bonding area. The data were analyzed with 2-factor ANOVA (p=0.05). RESULTS: (n=10) (Mean±SD).

	Adper Scotchbond SE	Adper Easy Bond	Single Bond Plus
E	18.9±6	19.2±5	22.6±7
D	23±5	25.7±5	26.1±6

 CONCLUSIONS: No significant difference was shown between the substrate or the bonding agent (p>.05).  Early in vitro results show that the self etching adhesives show promise as effective bonding agents.