Influence of handpiece maintenance sprays on resin bonding to dentin

Abstract

Toyotarou Sugawara1, Atsushi Kameyama2, Akiko Haruyama3, Takumi Oishi4, Nobuyuki Kukidome2, Yasuaki Takase2, Masatake Tsunoda21Undergraduate Student, Tokyo Dental College, Chiba, Japan; 2Division of General Dentistry, Tokyo Dental College Chiba Hospital, Chiba, Japan; 3Department of Dental Materials Science, Tokyo Dental College, Chiba, Japan; 4Department of Dentistry and Oral Surgery, Keio University School of Medicine, Tokyo, JapanObjective: To investigate the influence of maintenance spray on resin bonding to dentin.Materials and methods: The crown of extracted, caries-free human molars was transversally sectioned with a model trimmer to prepare the dentin surfaces from mid-coronal sound dentin, and then uniformly abraded with #600 silicon carbide paper. The dentin surfaces were randomly divided into three groups: oil-free spray group where maintenance cleaner for air bearing handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; oil-containing spray group where maintenance cleaner for micro motor handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; and control group where the surface was rinsed with water spray for 30 s and then air-dried. These surfaces were then bonded with Clearfil SE Bond (Kuraray Medical), and resin composite (Clearfil AP-X, Kuraray Medical) build-up crowns were incrementally constructed on the bonded surfaces. After storage for 24 h in 37°C water, the bonded teeth were sectioned into hour-glass shaped slices (0.7-mm thick) perpendicular to the bonded surfaces. The specimens were then subjected to microtensile bond strength (μTBS) testing at a crosshead speed of 1.0 mm/min. Data were analyzed with one-way ANOVA and the Tukey-Kramer test.Results: Maintenance spray-contaminated specimens (oil-free and oil-containing spray groups) showed significantly lower μTBS than control specimens (P < 0.05). However, there was no significant difference between the spray-contaminated groups (P > 0.05).Conclusion: Maintenance spray significantly reduces the bond strength of Clearfil SE Bond to dentin.Keywords: microtensile bond strength, lubricant, maintenance spray, contamination, dentin bonding