Shear Bond Strength of One 4th and Two 7th Generation Bonding Agents when used by Operators with Different Bonding Experience

Purpose: To test the hypothesis that simpler-to-use dentin adhesives (7th-generation adhesives) perform better when used by inexperienced operators than do the more complex 4th-generation adhesives. Materials and Methods: Six operators with no previous experience regarding dental adhesives, three residents in pediatric dentistry, and three experienced dentists used one 4th-generation dentin adhesive (MA) and two 7th-generation adhesives (MB and MC). With each adhesive, each operator performed 6 bondings to enamel and 6 bondings to dentin. After 24 h of storage in water at 37°C, the shear bond strength was determined. Results: The pooled results showed that the bond strength to dentin was higher (p 0.05) than that to enamel (dentin mean value = 14.0 MPa, SD = 9.1 MPa; enamel mean value = 11.9 MPa, SD = 7.1 MPa), and that adhesive MA performed better (p 0.05) than adhesives MB and MC (inexperienced operators = 16.2 ± 10.9 MPa, residents in pedodontics = 12.0 ± 6.8 MPa, and experienced operators = 10.7 ± 4.8 MPa). Of the two 7th-generation adhesives, one performed better on enamel than on dentin, while the other 7th-generation adhesive performed better on dentin than on enamel. Regarding operators, there were large individual variations. The inexperienced bonders performed as well as the residents (p > 0.05), while the experienced operators performed best (p 0.05). Conclusion: In general, the tested 4th-generation adhesive performed better than the 7th-generation adhesives. Even inexperienced operators performed better with the more difficult-to-use 4th-generation adhesives than with the 7th-generation adhesives. Dentin adhesion was stronger than enamel adhesion. Keywords: technique sensitivity, iBond, Scotchbond MP, Prompt-L-Pop