View the CAT printer-friendly / share this CAT
Title High-powered Nd:YAG Laser Surface Conditioning Prior to Bonding May Produce Bond Strengths Between Metal Brackets and Porcelain Equivalent to Those Produced Using Traditional Intraoral Hydrofluoric Acid
Clinical Question For adult orthodontic patients with porcelain/ceramic crowns (P), would application of laser surface conditioning (I) as compared to traditional acid-based etching (C) be as effective at preventing failure of the porcelain to metal bracket bond (O)?
Clinical Bottom Line While the standard practice of using hydrofluoric acid (HF) prior to silanation and bonding is effective for bonding metal orthodontic brackets to porcelain/ceramic crowns, substituting high-powered (1.5-2W) laser surface treatment for HF acid may be as effective on porcelain, without the risk that HF acid poses to tissues. This is supported by one systematic review and meta-analysis and an in vitro study that show comparable shear bond strengths in the laser groups. However, one systematic review and meta-analysis showed the reverse, probably because it did not distinguish the effects of laser power and laser type. Lasers are becoming more commonplace in orthodontic offices, and this intervention can save chair time.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 35036438Sobouti/2022Total n=1757 in 32 included studiesMeta-Analysis
Key resultsWeighted mean shear bond strength differences (WMD), ranges (95% confidence interval) and p values for different methods of crown surface preparation as compared to the “gold standard” treatment of HF acid, silane, and bonding are as follows: •2W Nd:YAG laser+silane+bonding protocol: -0.99 MPa, -2.79 MPa to +0.81 MPa, p=0.28 •1W Nd:YAG laser+silane+bonding: -3.09 MPa, -7.14 MPa to +0.95 MPa, p=0.13 •1.6W Er:YAG laser+silane+bonding: -2.79 MPa, -8.97 MPa to +3.55 MPa, p=0.40 •2W,2Hz CO2 laser+silane+bonding: -6.12 MPa, -8.04 MPa to -4.20 MPa, p<0.005) Only the CO2 laser treatment had significantly weaker shear bond strengths (SBSs) to porcelain. All other laser treatments produced comparable SBSs to that of the “gold standard”; however, the studies for the 1W Nd:YAG laser treatment had a very wide 95% CI, indicating a lower certainty of this conclusion.
#2) 35049723Francisco/2022Total n=7246 in 71 included studiesMeta-Analysis
Key resultsBased on the meta-analysis, the lithium disilicate ceramic crown bond was significantly improved in the laser group, with a mean SBS of 19.87 mPa, when compared to the other 4 groups (fine bur, sandblasting, orthophosphoric acid, HF acid; ranging from 0.7 to 9.18 MPa). With feldspathic ceramics, the HF acid-alone group had the highest mean SBS of 27.32 MPa, whereas the laser group was 26.79 MPa. However, both of these groups had a significantly higher SBS that the other groups (those ranged from 3.99 to 13.56 MPa).
#3) 24142046Hosseini/2015n=72 glazed porcelain samples duplicating labial surface of maxillary incisorsLaboratory study
Key resultsAs the power of the Nd:YAG laser treatments went up from 0.75W up to 2W, SBS increased, but only the 1.5W and 2W groups produced comparable SBSs to feldspathic porcelain as compared to the HF acid only group (SBS = 7 MPa ± 1.7 MPa, 9.6 MPa+2.7 MPa and 9.4 MPa+2.5 MPa, respectively). Nd:YAG lasers with at least 1.5W power is needed for an effective bond to to feldspathic porcelain.
Evidence Search (((((Orthodontic) AND (Bond)) AND (Bracket)) AND (Laser)) AND (Porcelain)) NOT (Zirconia)
Comments on
The Evidence
With both systematic reviews, the inclusion criteria were well-defined, the searches extensive, with a valid and relevant question asked prior. The results were presented with a lot of depth, included multiple forest plots, and showed relatively similar results between individual studies within the analyses. For the study by Francisco et. al., however, the systematic review did not include a consistent control group across all the included studies, with many not reporting one, and the analysis did not distinguish the effects of laser power or laser type. This may be the reason for the discrepancy in conclusions between this study and the other two, which showed that the high-powered Nd:YAG laser treatment produces comparable bond strength to feldspathic porcelain as HF treatment. The study by Sobouti et al. showed significant consideration for bias among the included studies, and most of them were adequately randomized; however blinding and consistency were inadequate between the different studies' parameters. The in vitro study by Hosseini was conducted with a clear control group and a gold-standard treatment group, had random grouping, and is applicable to a substantial number of patient treatment scenarios.
Applicability While there is an additional cost to an office, along with the added personal protection considerations, laser surface conditioning can be easily applied in a majority of orthodontic practices. Omitting the need for risky intraoral hydrofluoric acid, with a comparable bond strength, especially in lithium disilicate crowns using a 2W Nd:YAG laser, the laser technique could be a benefit to both practitioner and patient. Many adult orthodontic patients present with porcelain/ceramic crowns, and wish to have traditional brackets, or their treatment complexity necessitates them over clear aligners.
Specialty/Discipline (Orthodontics)
Keywords Ceramic, Bracket, Bond, Laser, Porcelain, Crown, Orthodontic, Bond strength
ID# 3542
Date of submission: 10/19/2023spacer
E-mail abdulhaqq@livemail.uthscsa.edu
Author Jeremy Haqq
Co-author(s) Nicole Meyer
Co-author(s) e-mail meyern1@livemail.uthscsa.edu
Faculty mentor/Co-author Dr. Kyumin Whang, B.S., M.S., Ph.D
Faculty mentor/Co-author e-mail whang@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
post a rationale
None available
Comments and Evidence-Based Updates on the CAT
post a comment
None available

Return to Found CATs list