Porcelain conditioning with Nd:YAG and Er:YAG laser for bracket bonding in orthodontics

Abstract

In this study, shear bond strength (SBS) of metal orthodontic brackets to porcelain following conditioning by Er:YAG (erbium-doped yttrium aluminum garnet) and Nd:YAG (neodymium-doped yttrium aluminum garnet) laser in comparison to conventional methods was evaluated. One hundred glazed porcelain discs with an upper central shape were prepared and randomly assigned to five equal groups of 20. In the first group, samples were only deglazed and roughened by diamond burs. In the second group, after roughening and deglazing of porcelain samples, the samples were etched by 9.6% hydrofluoric acid for 4 min. Groups, 3, 4, and 5 were prepared by 0.8-W Nd:YAG laser, 2-W Er:YAG laser, 3-W Er:YAG laser for 10 s, respectively. Then, metal, mesh-based brackets were bonded to porcelain samples, and after being stored in distilled water for 24 h, debonding was carried out by a Zwick testing machine. ANOVA and Tukey tests were used to compare SBS in five groups. Mean SBS in groups 1 to 5 were 3.3 ± 1.6, 7.0 ± 2.1, 6.9 ± 2.7, 2.3 ± 1.1, and 3.7 ± 2.3 MPa, respectively. ANOVA test revealed a significant difference between five groups (p < 0.05). Although Tukey's test showed SBS in groups 2 and 3 were significantly higher than the other groups, they did not differ with each other significantly (p > 0.05). The results revealed that SBS of 9.6% hydroflouric acid and Nd:YAG Laser was in an acceptable range for orthodontic treatment. Nd:YAG laser was shown to be an acceptable substitute for hydrofluoric acid while Er:YAG laser with the mentioned power and duration was not a suitable option.

Evaluation of the Effect of Four Surface Conditioning Methods on the Shear Bond Strength of Metal Bracket to Porcelain Surface

“…7 A number of alternative methods have been suggested to overcome this problem, such as deglazing and roughening the porcelain surface with a diamond bur, microetching the surface with aluminum oxide particles, conditioning the porcelain surface with the application of silane, and, most recently, lasers. 5,10,13,14,18,[21][22][23][24][25][26] Some of the previous studies [22][23][24][25] have evaluated the effect of Nd:YAG and Er:YAG lasers on porcelain surface treatment for efficient bracket bonding, whereas some other studies 5,26 have assessed the effectiveness of CO 2 laser for this purpose.…”

“…22,23 The results on the efficacy of Er:YAG laser in porcelain conditioning is more controversial. 22,24,25 Two studies evaluated the effect of CO 2 laser irradiation of porcelain surfaces on the bond strength of metal orthodontic brackets. 5,26 Akova et al 5 concluded that superpulse CO 2 laser irradiation provided adequate bonding strength between metal brackets and porcelain surfaces.…”

“…In previous studies, the efficacy of different types of lasers on porcelain surface preparation has been evaluated. 5,[22][23][24][25][26] Some studies claimed that Nd:YAG laser with appropriate parameters can be used as an alternative method for porcelain etching. 22,23 The results on the efficacy of Er:YAG laser in porcelain conditioning is more controversial.…”

“…5,[22][23][24][25][26] Some studies claimed that Nd:YAG laser with appropriate parameters can be used as an alternative method for porcelain etching. 22,23 The results on the efficacy of Er:YAG laser in porcelain conditioning is more controversial. 22,24,25 Two studies evaluated the effect of CO 2 laser irradiation of porcelain surfaces on the bond strength of metal orthodontic brackets.…”

Orthodontic bonding to porcelain: A systematic review

“…The results prove that the 2W/20-second superpulse CO 2 laser irradiation provides acceptable bond strength of metal brackets to porcelain surfaces. Poosti et al 21 proved that laser irradiation by Nd:YAG laser is an acceptable substitute for hydrofluoric acid; however, the Er:YAG laser is not an acceptable option.…”