Effect of altering the type of enamel conditioner on the shear bond strength of a resin-reinforced glass ionomer adhesive.
The purpose of this study was to determine the effects of changing the type of enamel conditioner on the shear bond strength of a resin-reinforced glass ionomer within half an hour after bonding the bracket to the tooth. Freshly extracted human molars were collected and stored in a solution of 0.1% (weight/volume) thymol. The teeth were cleaned and polished. The teeth were randomly separated into 4 groups according to the enamel conditioner/etchant and adhesive used: group I, teeth were conditioned with 10% polyacrylic acid and brackets were bonded with a resin-reinforced glass ionomer adhesive; group II, teeth were conditioned with 20% polyacrylic acid and brackets were bonded with a resin-reinforced glass ionomer adhesive; group III, teeth were etched with 37% phosphoric acid and the brackets were bonded with a resin-reinforced glass ionomer adhesive; group IV, teeth were etched with 37% phosphoric acid and the brackets were bonded with a composite adhesive. The results of the analysis of variance comparing the 4 experimental groups (F = 24.87) indicated the presence of significant differences between the groups (P =.0001). In general, the shear bond strengths were significantly greater in the 2 groups etched with 37% phosphoric acid. This was true for both the resin-reinforced glass ionomer (X = 6.1 +/- 2.7 MPa) and the composite (X = 5.2 +/- 2.9 MPa) adhesives. On the other hand, the shear bond strengths were significantly lower in the two groups conditioned with polyacrylic acid. The bond strength of the resin-reinforced glass ionomer adhesive conditioned with 10% polyacrylic acid (X = 0.4 +/- 1.0 MPa) was significantly lower than the group conditioned with 20% polyacrylic acid (&xmacr; = 3.3 +/- 2.6 MPa). The present findings indicated that the bond strength of the resin-reinforced glass ionomer adhesive can be significantly increased in the initial half hour after bonding if the enamel is etched with 37% phosphoric acid instead of being conditioned with either 10% or 20% polyacrylic acid. The clinician needs to take these properties into consideration when ligating the initial archwires.
Bishara
S E
SE
College of Dentistry, University of Iowa, Iowa City, IA 52242-1001, USA.
Vonwald
L
L
Laffoon
J F
JF
Jakobsen
J R
JR
D000134:Acid Etching, Dental / Q000379:methods*; D000180:Acrylic Resins; D000538:Aluminum Silicates; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D016009:Chi-Square Distribution; D001840:Dental Bonding; D003743:Dental Enamel / Q000187:drug effects; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D006801:Humans; D016910:Orthodontic Brackets; D010756:Phosphoric Acids; D011897:Random Allocation; D019279:Resin Cements; D018709:Statistics, Nonparametric; D013718:Tensile Strength
D000180:Acrylic Resins; D000538:Aluminum Silicates; D017220:Dentin-Bonding Agents; C095451:Fuji Ortho LC; D005899:Glass Ionomer Cements; D010756:Phosphoric Acids; D019279:Resin Cements; C065742:Transbond; D017438:Bisphenol A-Glycidyl Methacrylate; C006903:carbopol 940; C030242:phosphoric acid