Shear bond strength of brackets bonded to amalgam with different intermediate resins and adhesives

Abstract

The aims of this study were to compare, in vitro, the shear bond strength (SBS) of stainless steel orthodontic brackets bonded to silver amalgam with the use of three different intermediate resins and two different adhesives, and to evaluate bond failure mode. Forty-five amalgam specimens were divided into three equal groups. In groups 1 and 2, the brackets were bonded with Unite (3M Unitek) using Reliance Metal Primer (RMP; Reliance Orthodontic Products) and Power Bond OLC (PB OLC; Ortho Organizers Inc.) as intermediate resins, respectively. In group 3, Resinomer and One-Step Plus (OS+; Bisco Inc.) were used. Thirty bovine teeth served as the controls to test bracket bonding to acid-etched enamel with Unite and Resinomer-OS+. After thermocycling from 10 to 50 degrees C 1000 times, all samples were tested for SBS. Bond failure sites were classified using a modified adhesive remnant index (ARI) system. Data were analyzed with one-way analysis of variance, post hoc Tukey multiple comparison and chi-square tests. The results showed that the mean SBS to amalgam surfaces were significantly lower than those to etched bovine enamel (P<0.001). There were no statistically significant differences in mean SBS between the amalgam bonding groups (P>0.05). For the ARI, significant differences were found between the amalgam- and enamel-bonding groups (P<0.001). The mean SBS of stainless steel orthodontic brackets bonded to amalgam surfaces with RMP, PB OLC, OS+ intermediate resins and Unite and Resinomer adhesives was significantly lower than to etched bovine enamel. Bond failure occurred at the amalgam-adhesive interface regardless of the adhesive system and without damage to the amalgam restoration.

Amalgam Surface Treatment by Different Output Powers of Er:YAG Laser:SEM Evaluation

“…3,4 Surface treatment can be done by diamond bur, sandblasting, and chemical corrosion to improve bonding to amalgam surface. 5 The application of lasers for treatment of dental substrate has gained special attention.…”

Adhesive strength of metal brackets on existing composite, amalgam and restoration-enamel complex following air-abrasion protocols

“…Especially with the increase in adult patients, orthodontists are more likely to bond brackets onto composite and amalgam restorations on the buccal tooth surfaces depending on the location. A vast number of studies have been performed investigating the adhesive performance of brackets on restorative material surfaces [3][4][5][6][7][8][9]. Additional surface conditioning methods increasing surface roughness and the use of intermediate adhesive resin have been reported to improve bond strength on such surfaces [3][4][5][6][7][8].…”

“…A vast number of studies have been performed investigating the adhesive performance of brackets on restorative material surfaces [3][4][5][6][7][8][9]. Additional surface conditioning methods increasing surface roughness and the use of intermediate adhesive resin have been reported to improve bond strength on such surfaces [3][4][5][6][7][8]. These procedures have become a part of the routine clinical practice, aiming surface area increase for better micromechanical retention and at the same time forming chemical bonds between the adhesive and the restorative materials [9,10].…”

“…Air-abrasion produces etchedenamel like surfaces with a significant surface area increase [8,[10][11][12] where air-abrasion with SiO 2 , the so called silica-coating, has presented the additional advantage of providing a chemically active surface, which was then enhanced by the application of silane coupling agents. Commercial silanes contain chemical adhesion promoters such as silane methacrylate, phosphoric acid methacrylate and sulfide methacrylate through which adhesion could be enhanced [10,[11].…”

“…Commercial silanes contain chemical adhesion promoters such as silane methacrylate, phosphoric acid methacrylate and sulfide methacrylate through which adhesion could be enhanced [10,[11]. This improvement is due to covalent bonds formed between the adhesive resin and the coated area, which is considered adjunct to the mechanical retention increasing bond strength of resin-based materials to different substrates [8,[10][11][12]13].…”