Effect of Different Surface Treatments and Orthodontic Bracket Type on Shear Bond Strength of High-Translucent Zirconia: An In Vitro Study

Abstract

Objective. Considering the increasing number of adults seeking orthodontic treatment, and the possible need for bracket bonding to monolithic zirconia restorations, knowledge about the preferred type of bracket (metal/ceramic) and the most efficient surface treatment is imperative to achieve acceptable shear bond strength (SBS). This study aimed to assess the effect of different surface treatments and orthodontic bracket types on SBS of high-translucent zirconia. Materials and Methods. Totally, 248 disc-shaped zirconia specimens were assigned to two groups for bonding to metal and ceramic brackets. Each group was divided into four subgroups (n = 31) for the following surface treatments: no surface treatment (control group), airborne-particle abrasion (APA), tribochemical silica coating with CoJet, and CO2 laser irradiation. The mean surface roughness (Ra value) was measured. The SBS was measured after bracket bonding and thermocycling. Data were analyzed by two-way ANOVA, Tukey, Kruskal–Wallis, Mann–Whitney, and Fisher exact tests, and Bonferroni correction ( α = 0. 05 ). Results. The mean Ra value was significantly different among the surface treatment subgroups ( P < 0.001 ). The APA and CoJet subgroups were not significantly different regarding Ra ( P = 0.754 ). All other pairwise comparisons yielded significant differences ( P < 0.001 ). Bracket type, surface treatment, and their interaction significantly affected the SBS ( P < 0.001 ). Ceramic brackets bonded to zirconia surfaces treated with CoJet yielded the maximum SBS while ceramic brackets bonded to control and lased surfaces resulted in minimum SBS. No significant difference was noted in the SBS of different surface treatment groups when metal brackets were used ( P > 0.05 ). Conclusions. The use of ceramic brackets and CoJet surface treatment would be the most appropriate combination to achieve optimal bonding to high-translucent zirconia restorations.

The possibility of clinical bonding between metal/ceramic brackets to zirconia: in vitro study

“…The rising demand for dental aesthetics has led to an increased number of individuals seeking orthodontic treatment, including adults with a history of fixed prosthetic treatments ( Babaee Hemmati et al, 2022 ). Orthodontic brackets are categorized as metal or ceramic brackets.…”

Mechanical and chemical surface treatment enhances bond strength between zirconia and orthodontic brackets: an in vitro study

“…This is likely because bur roughening exposes and create micropores on the zirconia substructure, which is different from other mechanical and chemical methods, such as air abrasion and hydrofluoric acid etching [ 11 ]. In vitro studies have shown that there is no significant difference in the SBS between metal brackets and zirconia crowns after air abrasion [ 10 , 14 ], tribochemical silica coating, or carbon dioxide laser irradiation compared with no surface treatment [ 10 ]. Although a higher bond strength has been reported when using air abrasion compared with using a soflex disc [ 16 ], this might be due to the smaller grit size in the solflex disc, which is insufficient to roughen the zirconia surface.…”

“…The factors affecting the adhesion of an orthodontic bracket to zirconia includes the bracket materials [ 9 , 10 ] and surface treatment conditions [ 4 , 10 – 17 ], comprising mechanical and chemical protocols. Mechanical surface treatments include polishing with a prophy cup and pumice [ 11 ], air abrasion with alumina oxide particles [ 11 , 14 , 15 ], surface roughening [ 16 ], and laser irradiation [ 10 , 13 ]. Moreover, chemical surface treatments include etching with various acids, such as orthophosphoric [ 14 ] and hydrofluoric acid [ 11 , 13 ], and primer application [ 11 , 12 , 17 ].…”

“…Moreover, chemical surface treatments include etching with various acids, such as orthophosphoric [ 14 ] and hydrofluoric acid [ 11 , 13 ], and primer application [ 11 , 12 , 17 ]. In addition, the significant impact of combined mechanical and chemical method such as tribochemical silica coating [ 10 , 13 ], and types of resin adhesive [ 16 ] on adhesion has been reported. Although a recent systematic review demonstrated the positive effect of air abrasion and laser treatment of zirconia for bonding with orthodontic brackets [ 4 ], due to the heterogeneity among studies, it has not been determined which surface treatment methods should be recommended as the standard protocol.…”