Primer-Treated Ceramic Bracket Increases Shear Bond Strength on Dental Zirconia Surface.

Ga-Youn Ju,Bum-Soon Lim,Shin-Young Park,Wonjoon Moon,Soram Oh,Shin Hye Chung

doi:10.3390/ma13184106

Ga-Youn Ju, Bum-Soon Lim + Show 4 more

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https://doi.org/10.3390/ma13184106

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Abstract

The purpose of this study is to evaluate the shear bond strength (SBS) of a primer-treated ceramic bracket on dental zirconia and to compare it with conventional ceramic bracket bonding on surface-treated zirconia. Sintered and finished dental zirconia was sandblasted. Samples were divided according to the treated surfaces: no treatment (X), ceramic primer on zirconia (Z), ceramic primer on bracket base (B), and ceramic primer on both zirconia and bracket base (ZB). The ceramic bracket was bonded on zirconia and SBS was measured before (T0) and after 10,000 cycles of thermocycling (Tf). The failed surfaces were examined under field emission scanning electron microscope (FE-SEM), and adhesive remnant index (ARI) was evaluated. SBS was significantly higher in ZB and significantly lower in X in both T0 and Tf. There was no significant difference between Z and B. In X and B, adhesive failure occurred while ZB showed mixed failures. There was no apparent change in the zirconia surface except for the existence of some adhesive and resin remnants. The application of ceramic primer on the bracket base increased the bonding strength to the level of conventional bonding with fewer adhesive remnants. The highest bonding strength was obtained when the primer-treated bracket was bonded on the primer-treated zirconia.

Highlights

This study shows that the new strategy, i.e., primer treatment on the bracket base, can sufficiently increase the shear bond strength (SBS) of brackets, but can provide an option for stronger bonding on zirconia
The bracket base showed multiple spherical-shaped retentive roughness (Ra ) of 0.773 μm (Figure 1).80The base showed multiple spherical-shaped retentive beads
It was concluded that primer application on the bracket base increases bonding strength to a sufficient level with less adhesive paste on the zirconia

Summary

Introduction

Increasing interest in esthetics and the need to overcome the disadvantages of traditional porcelain-fused metal crowns, e.g., the low strength of porcelain and greyish shade of gingiva from metal substructures, have resulted in the development of a wide range of ceramic systems [1,2].Among them, the use of dental zirconia has increased with the development of computer-aided manufacturing (CAM) devices.Polycrystalline zirconia, a frequently used ceramic system in load bearing areas with esthetic demands, primarily consists of yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) [3,4,5].The phase transformation of Y-TZP from tetragonal to monoclinic under stress conditions increases the particle volume and inhibits crack propagation, resulting in high flexural strength [3,4,6]. Increasing interest in esthetics and the need to overcome the disadvantages of traditional porcelain-fused metal crowns, e.g., the low strength of porcelain and greyish shade of gingiva from metal substructures, have resulted in the development of a wide range of ceramic systems [1,2]. Polycrystalline zirconia, a frequently used ceramic system in load bearing areas with esthetic demands, primarily consists of yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) [3,4,5]. The phase transformation of Y-TZP from tetragonal to monoclinic under stress conditions increases the particle volume and inhibits crack propagation, resulting in high flexural strength [3,4,6]. Due to its outstanding mechanical properties, zirconia has been used in inlays, onlays, crowns, post-and-core systems and as frameworks for porcelain fused zirconia (PFZ) restorations [4,7].

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