title: Adhesive thickness effects on the bond strength of a light-cured resin-modified glass ionomer cement.
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.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey. sarici@omu.edu.tr
authors.forename: Selim
authors.initials: S
authors.lastname: Arici
authors.forename: Cem Mustafa
authors.initials: CM
authors.lastname: Caniklioglu
authors.forename: Nursel
authors.initials: N
authors.lastname: Arici
authors.forename: Mete
authors.initials: M
authors.lastname: Ozer
authors.forename: Benan
authors.initials: B
authors.lastname: Oguz
mesh_terms: D000180:Acrylic Resins; D000269:Adhesives; D000293:Adolescent; D000538:Aluminum Silicates; D000704:Analysis of Variance; D001641:Bicuspid; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D016910:Orthodontic Brackets; D019279:Resin Cements; D033081:Shear Strength; D016019:Survival Analysis; D013718:Tensile Strength
chemical_list: D000180:Acrylic Resins; D000269:Adhesives; D000538:Aluminum Silicates; C112133:Fuji Ortho; D005899:Glass Ionomer Cements; D019279:Resin Cements; C477790:Transbond XT