Influence of various surface-conditioning methods on the bond strength of metal brackets to ceramic surfaces

Abstract

With the increase in adult orthodontic treatment comes the need to find a reliable method for bonding orthodontic brackets onto metal or ceramic crowns and fixed partial dentures. In this study, shear bond strength and surface roughness tests were used to examine the effect of 4 different surface conditioning methods: fine diamond bur, sandblasting, 5% hydrofluoric acid, and silica coating for bonding metal brackets to ceramic surfaces of feldspathic porcelain. Sandblasting and hydrofluoric acid were further tested after silane application. A total of 120 ceramic disc samples were produced, and 50 were used for surface roughness measurements. The glazed ceramic surfaces were used as controls. Metal brackets were bonded to the ceramic substrates with a self-curing composite. The samples were stored in 0.9% NaCl solution for 24 hours and then thermocycled (5000 times, 5 degrees C to 55 degrees C, 30 seconds). Shear bond tests were performed with a universal testing device, and the results were statistically analyzed. Chemical surface conditioning with either hydrofluoric acid (4.3 microm) or silicatization (4.4 microm) resulted in significantly lower surface roughness than mechanical conditioning (9.3 microm, diamond bur; 9.7 microm, sandblasting) (P <.001). The surface roughness values reflect the mean peak-and-valley distances. The bond strengths of the brackets bonded to the ceramic surfaces treated by hydrofluoric acid with and without silane (12.2 and 14.7 MPa, respectively), silicatization (14.9 MPa), and sandblasting with silane (15.8 MPa) were significantly higher (P <.001) than those treated by mechanical roughening with fine diamond burs (1.6 MPa) or sandblasting (2.8 MPa). The highest bond strength values were obtained with sandblasting and silicatization with silane or hydrofluoric acid without silane; these fulfilled the required threshold. The use of silane after hydrofluoric acid etching did not increase the bond strength. Diamond roughening and sandblasting showed the highest surface roughness; they can damage the ceramic surface. Acid etching gave acceptable results for clinical use, but the health risks should be considered. The silicatization technique has the potential to replace the other methods; yet cohesive failures were observed in the ceramic during removal of the brackets.

Shear Bond Strength of Al2O3 Sandblasted Y-TZP Ceramic to the Orthodontic Metal Bracket

“…With regard to the bond strength required for adequate bonding of the orthodontic metal bracket, Maijer et al [52] suggested that the minimum bond strength required for dental clinical use is 5.9–7.9 MPa and Schmage et al [40] proposed that 6–10 MPa strength is necessary to support normal orthodontic forces. Based on these studies, groups treated with MDP (AM group, 11.92 ± 1.51 MPa) and MDP containing silane primers (AMS group, 13.36 ± 2.31 MPa) after sandblasting were shown to have sufficient bond strength (Figure 1).…”

“…The MDP primer was applied to increase the bond strength between the metal bracket for maxillary central incisor (Archist Bracket, Daeseung medical, Seoul, Korea) and the resin cement, after which, the bracket was bonded to the surface treated Y-TZP under a force of about 5 N [40] using the resin cement (Transbond XT, 3M Unitek, Monorvia, CA, USA). Excess resin cement was removed with an explorer, and the remaining resin cement was light cured for 20 s on each side using a halogen light curing unit (Demetron Optilux, Kerr model-VCL 401, Demetron Research, Danbury, CT, USA) at an angle of 45°.…”

Shear bond strength of orthodontic metal brackets to aged composite using three primers

“…Shear loads are among the most common and most destructive forces applied in the oral environment, which can cause debonding of brackets (15). Some researchers have attempted to improve the bond strength of orthodontic attachments to amalgam and porcelain (16) but studies on methods to improve the bond strength of orthodontic brackets to aged composite restorations are scarce.…”

Bonding Orthodontic Ceramic Brackets to Ceramic Restorations: Evaluation of Different Surface Conditioning Methods

“…Ceramic restorations, such as ceramic crowns or veneers, which are adhesively bonded to teeth, can be nowadays more often found in orthodontic patients because of an increasing number of adult patients who ask for a treatment [2]. Several methods have been suggested to strengthen the bond strength between ceramics and brackets: it was described to roughen the porcelain with diamond burs, green stones or abrasive disks [2,4]. Others described for getting more retention to cut a retention cavity in the ceramic surface [5].…”

“…The danger in handling hydrofluoric acid is extreme, as skin saturation with the acid in areas of only 25 square inches (160 cm 2 ) may be relatively painless, yet ultimately fatal. High concentrations of hydrofluoric acid and hydrogen fluoride gas will also quickly destroy the corneas of the eyes [2,4].…”