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

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.

The effect of surface treatment and thermocycling on the shear bond strength of orthodontic brackets to the Y-TZP zirconia ceramics: A systematic review

“… 12 , 15 - 18 , 25 , 28 Sandblastings and lasers were also combined with various primers and universal adhesive. 2 , 14 , 15 , 19 , 20 , 22 , 25 , 27 , 28 Eight studies treated Y-TZP surface with sandblasting only; 4 , 12 , 14 , 16 - 18 , 27 five studies combined sandblasting with silane primer, 14 , 17 , 19 , 20 , 25 five studies combined sandblasting with MDP (methacryloyloxydecyl dihydrogen phosphate) primers; 14 , 19 , 20 , 27 , 28 four studies combined universal adhesive; 2 , 19 , 20 , 27 three studies combined MDP containing silane primer, 2 , 14 , 20 and two studies combined zirconia primer. 22 , 27 Lasers were used alone in four studies; 12 , 16 - 18 and as an adjunct with MDP primer and silane primer in one study each.…”

“…Following both forms of sandblasting, primers like silane, MDP, MDP containing silane primers or single-step universal adhesives were applied to optimize the SBS. 2 , 4 , 19 , 20 , 22 The primers and universal adhesives that contain MDP are capable of chemically bond to zirconia. The bonding occurs between the phosphate ester of MDP and the hydroxyl groups over the zirconia surface.…”

“…Three types of brackets were studied. Metallic brackets were the most common; [11][12][13][14][15][16][17][18][19][20][21][22][23][24] followed by the ceramic 2,4,15,17,23,24,26,27 , and sapphire brackets. 28 Both mechanical and chemical methods of surface treatment were identified on the Y-TZP zirconia surface.…”

“…Mechanical means included lasers, sandblasting, polishing and soflex disc, silicon carbide paper, and diamond bur roughening. 2,4,[12][13][14][15][16][17][18][19][20][21]25,26,28 Chemically, acid etching (9.6% hydrofluoric acid, 37% phosphoric acid), application of primers, and universal adhesive were found. 2,12,14,[16][17][18][19][20]22,25,27,28 Sandblasting was the most found surface treatment.…”

“… 3 It has been used extensively to make inlays, onlays, crowns, post and core systems, and frameworks for porcelain fused to zirconia restorations. 4 Hence, with the increasing use of zirconia restorative materials, it is becoming more common for orthodontists to bond orthodontic brackets to a Y-TZP surface. However, due to the chemical inertness and resistance to acid-etching, bonding composite resin to the zirconia surface can be challenging.…”