Effect of alloy type and surface conditioning on roughness and bond strength of metal brackets

Abstract

The effect of 5 different surface conditioning methods on bonding of metal brackets to cast dental alloys was examined. The surface conditioning methods were fine (30-microm) or rough (125-microm) diamond bur, sandblasting (50-microm or 110-microm aluminum oxide [Al2O3]), and silica coating (30-microm silica). Fifty disc-shaped specimens of 5 different alloys (gold-silver, palladium-silver, nickel-chromium, cobalt-chromium, and titanium) were ground with 1200-grit silicone carbide abrasive and polished before being reused for each conditioning method. Polished surfaces were used as negative controls. After measuring surface roughness (RZ), metal brackets were bonded to the conditioned alloys with a self-curing resin composite. Specimens were thermocycled (5000 times, 5 degrees-55 degrees C, 30 seconds), and shear bond tests were performed. Significantly higher (P<.001) surface roughnesses were observed with use of the rough diamond bur (RZ approximately 33 microm), 110-microm Al2O3 (RZ approximately 14 microm), and fine diamond bur (RZ approximately 10 microm), compared with the controls (RZ approximately 1 microm). Silica coating (RZ approximately 4 microm) and 50-microm Al2O3 (RZ approximately 4 microm) demonstrated no significant difference (P>.001) in roughness when compared with the controls. The control group showed no resistance to shear forces (0 MPa). Bond values were greater (19 MPa) when silica coating was used, compared with 50-microm Al2O3 (7 MPa) and 110-microm Al2O3 (8 MPa) for all alloys tested. However, interaction between alloys and conditioning methods exhibited significant differences (P<.0001).

Bonding durability between acrylic resin adhesives and titanium with surface preparations

“…In addition, energy-dispersive X-ray analysis revealed that a high alumina (26.0 wt%) content remained on the titanium surface after alumina abrasion and that the SiO 2 content on the titanium surface was 13.7 wt% after ROC tribochemical silica coating 21) . According to a previous study, the surface roughness of titanium after 110-μm particle alumina abrasion was larger than that after 50-μm particle alumina abrasion 24) . Although the particle size for ROC-a is larger (110-μm) than that for SAN (50-70-μm), in the present study, the Rz values did not differ significantly between ROC-a and SAN (Table 3).…”

Adhesion of orthodontic brackets to indirect laboratory-processed resin composite as a function of surface conditioning methods and artificial aging

“…Half of the specimens from each group were randomly (n=10 per group) selected and subjected to thermocycling (Nova, Nova Co, Konya, Turkey) for 1000 cycles [9], between 5-55°C, with a transfer time of 30 s and a dwell time of 30 s [16]. After thermocycling, the specimens were loaded at the bracket-specimen interface at a crosshead speed of 0.5 mm/min in a Universal Testing Machine (Lloyd Instruments, Hampshire, UK) until failure.…”

“…Although shear bond strength of metal orthodontic brackets to amalgam, methacrylate-based resin composites and dental ceramics have been widely investigated [14][15][16][17], their adhesion to IRCs have not been reported.…”

Effect of silica coating on bond strength between a gold alloy and metal bracket bonded with chemically cured resin

“…However, more and more orthodontists are using direct bonding to metal restorations because of improved oral hygiene, as well as convenience to the practitioner, compared with the conventional method using bands. Recently, chemicophysical bonding using a silica coating and silanation (silicoating),7,8 which can enhance mechanical and chemical bonds, has been introduced in the field of orthodontics. Chemically cured resin is more fully polymerized than light-cured resin, particularly in the central area of the bracket, when a metal bracket is bonded to gold alloy 9.…”