Article

Adhesive thickness effects on the bond strength of a light-cured resin-modified glass ionomer cement.

Department of Orthodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey.
The Angle Orthodontist (Impact Factor: 1.28). 03/2005; 75(2):254-9. DOI: 10.1043/0003-3219(2005)075<0250:ATEOTB>2.0.CO;2
Source: PubMed

ABSTRACT These in vitro studies investigated the effect of adhesive thickness on the tensile and shear bond strength of a light-cured, resin-modified glass-ionomer cement (FO). A light-cured conventional composite resin (CO) was used as the control material. Mesh-based metal brackets were bonded to extracted human premolars using FO and CO. The adhesive thickness was controlled by a special device and 0, 0.25, and 0.5 mm thicknesses were tested for both bonding agents. All bonded specimens were stored in distilled water at 37 degrees C for 48 hours and thermocycled between 5 degrees C and 55 degrees C for 200 cycles before testing. Analysis of variance showed that bond strength was significantly affected by the adhesive thickness (P < .001) and type of adhesive (P = .001). There were statistically significant differences between the mean bond strengths of the groups at the P < .05 level of significance. For all adhesive thicknesses, CO had higher bond strength values than those of FO in both test modes. The bond strength values were also analyzed using a Weibull analysis, which showed the most favorable adhesive thickness, and the 5% and 90% probabilities of failures was 0.25 mm in the FO groups. Bracket-adhesive interface failure was predominant for all groups in tensile testing, but enamel-adhesive interface failures increased with increased adhesive thickness in shear testing for the FO. This study suggests that adhesive thickness under a bracket could be particularly important when using a FO in direct bonding.

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    • "A small amount of Transbond XT resin (3M Unitek, Monrovia, CA, USA) was placed on the bracket's mesh, and the brackets were then immediately placed in the centres of the vestibular surfaces. Previous studies (Arici et al., 2005; Muguruma et al., 2010) have shown that the resin thickness affect the bond strength; thus, a force of 453.59 g was applied to the centre of each bracket aided by a Gillmore needle to standardize the resin thickness. "
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