Garshasbzadeh NZ, Mirzaie M, Yassini E, Shahabi S, Benedicenti S, Angiero F, Chiniforush N
Microsc Res Tech. 2016 Apr,79(4):328-33. doi: 10.1002/jemt.22634. Epub 2016 Feb
PMID: 26873266

Abstract

The study aimed to evaluate the effect of different output powers of Er:YAG laser on microtensile bonding strength of indirect composite to resin cements.36 indirect composite blocks (GC Gradia DA2, Japan) size 15 x 10 x 10 mm(3) were constructed, and divided into 12 groups, as follows:G1: control group (no treatment), Groups G2 to G6: treated with Er:YAG laser (2,940 nm) in noncontact mode, frequency 20 Hz, pulse duration 470 micros, with output power ranging from 2W to 6W, Groups G7 sandblasting, Groups 8 to G12: as Groups G2 to G 6 with preparatory sandblasting. One specimen from each group was analyzed by SEM, each specimen was fixed to a specialized metal jig using cyanoacrylate (Mitreapel, Beta Kimya San. Ve TIC, Iran) and debonded under tension with a universal testing machine (Zwick, Germany) at a crosshead speed of 0.5 mm min(-1) . Sandblasting and laser can improve bond strength above an energy level of 150 mJ. SEM evaluation of laser-treated specimens showed irregularities and deep undercuts. T test analysis showed no significant difference between sandblasted and non-sandblasted group, with laser output power of 0, 100, or 150 mJ (P = 0.666, P = 0.875, and P = 0.069), in the specimens irradiated with energy output of 200, 250, or 300 mJ, sandblasted specimens showed higher bond strength than non-sandblasted ones. The results demonstrate that, in composite resin irradiated with laser at energy output of 200-300 mJ, sandblasting might be a suitable procedure to enhance bond strength of resin cement. Microsc. Res. Tech. 79:328-333, 2016. (c) 2016 Wiley Periodicals, Inc.

Keywords
Er:YAG laser, indirect composite, microtensile strength