Light-curing efficiency of dental adhesives by gallium nitride violet-laser diode determined in terms of ultimate micro-tensile strength

Article type: Research Article

Authors: Kameyama, Atsushi^{; ;} | Kato, Junji^; | De Munck, Jan | Hatayama, Hitoshi | Haruyama, Akiko | Yoshinari, Masao | Takase, Yasuaki | Van Meerbeek, Bart | Tsunoda, Masatake

Affiliations: Division of General Dentistry, Tokyo Dental College Chiba Hospital, Chiba, Japan | Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology, and Maxillo-facial Surgery, Catholic University of Leuven, Leuven, Belgium | Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan | Lightwave Network Products Division, SEI Optifrontier Co., Chigasaki, Japan | Division of Oral Implants Research, Oral Health Science Center, Tokyo Dental College, Chiba, Japan

Note: [] Address for correspondence: Atsushi Kameyama, Senior Assistant Professor, Division of General Dentistry, Tokyo Dental College Chiba Hospital, 1-2-2 Masago, Mihama-ku, Chiba 261-8502, Japan. Tel.: +81 43 270 3958; Fax: +81 43 270 3943; E-mail [email protected].

Abstract: The purpose of this study was to evaluate whether violet-laser diode (VLD) can be used as light-curing source. The ultimate (micro-)tensile strength (μTS) of three adhesives was determined when cured by VLD in comparison with curing by two different types of commercial LED light-curing units. One VLD (VLM 500) and two LED units (Curenos and G-Light Prima) were used to cure the adhesive resin of the two-step self-etch adhesives Clearfil SE Bond, Tokuso Mac Bond II, and FL-Bond II. A 0.6-mm thick acrylic mould was filled with adhesive resin and cured for 60 s. After 24-h water storage, specimens were trimmed into an hourglass shape with a width of 1.2 mm at the narrowest part, after which the μTS was determined (n=10). In addition, the light transmittance of each adhesive was characterized using a UV-vis-NIR spectrometer. No significant difference in curing efficiency between VLD and LED were observed for both Tokuso Mac Bond II and FL-Bond II (p>0.05). For Clearfil SE Bond, the μTS of VLD-cured specimens was higher than that of the specimens cured by the LED Curenos unit (p<0.05). Spectrometry revealed that this marked difference must be attributed to a different light transmittance of Clearfil SE Bond for visible blue light versus for the lower area of UV and visible violet light. In conclusion, A GaN-based violet laser diode can be used as light-curing source to initiate polymerization of dental resins.

Keywords: Violet laser diode, light-curing unit, dental adhesive, ultimate tensile strength, UV-vis-NIR spectra, photo-initiator

DOI: 10.3233/BME-2012-0682

Journal: Bio-Medical Materials and Engineering, vol. 21, no. 5-6, pp. 347-356, 2011