Shear bond strength of metal brackets to feldspathic porcelain treated by Nd:YAG laser and hydrofluoric acid

Abstract

Adult orthodontic treatment requires bonding orthodontic attachment to dental restorations. Ceramics are commonly used as esthetic restorative materials for the crowns and bridges. The present study evaluated the shear bond strength of metal orthodontic brackets to the feldspathic porcelain surfaces following conditioning by different powers of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser and hydrofluoric acid as a conventional method. Seventy-two glazed porcelain samples were prepared and randomly attributed to six equal groups of 12. In the conventional hydrofluoric (HF) group, the specimens were etched by 9.6% hydrofluoric acid for 4 min. In laser groups, samples were conditioned by 0.75-, 1-, 1.25-, 1.5-, and 2-W Nd:YAG laser for 10 s. Metal brackets were bonded to porcelain samples and after being stored in distilled water for 24 h, they were subjected to thermocycling for 500 cycles. The debonding was carried out by a Zwick testing machine. The data were statistically analyzed by ANOVA and Tamhane multiple comparisons tests. The mean ± SD of the shear bond strength in the laser group 0.75, 1, 1.25, 1.5, and 2 W and HF group was 2.2 ± 0.9, 4.2 ± 1.1, 4.9 ± 2.4, 7 ± 1.7, 9.6 ± 2.7, and 9.4 ± 2.5, respectively. Together with the increased power of laser, the mean shear bond strength was increased continuously and no significant differences were found between the HF group and the laser groups with power of 1.5 or 2 W. Also, there was no significant difference between all test groups in ARI scores. There was no significant difference between bond strength of laser groups with power of 1.5 and 2 W and HF-etched group. So, Nd:YAG laser with appropriate parameters can be used as an alternative method for porcelain etching.

Effect of Femtosecond Laser Treatment on the Shear Bond Strength of a Metal Bracket to Prepared Porcelain Surface

“…In the current study, the SBS value of the NY group (5.11 MPa) was the lowest among the groups, which was not adequate for clinical application (6)(7)(8)(9)(10). 15 This finding is consistent with the results of Hosseini et al 33 It has been reported that a gradual increase in the output power of NY lasers improved the SBS of the bracket-to-porcelain surface. In contrast, Poosti et al 12 reported the SBS of bracket-to-porcelain surface to be 6.9 MPa, using a 0.8 W NY laser.…”

“…Numerous studies have shown that NY laser use is an effective technique for bracket adhesion. 32,33 In a recent study, an NY with a 4 W output power, 40 Hz repetition rate, and 300 lm diameter optical fiber was used for surface treatment. In the current study, the SBS value of the NY group (5.11 MPa) was the lowest among the groups, which was not adequate for clinical application (6)(7)(8)(9)(10).…”

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

“…5,[22][23][24][25][26] It has been proven that CO 2 wavelength is absorbed almost totally by porcelain, suggesting that it as a good candidate for porcelain surface treatment. 5,28 Some investigators 5,26 used the CO 2 laser as the present study, and reported satisfying results in SBS as a result of conditioning the porcelain surface by CO 2 laser.…”

“…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.…”