Surface conditioning of a composite used for inlay/onlay restorations: effect on muTBS to resin cement.
OBJECTIVE
To assess the effect of the composite surface conditioning on the microtensile bond strength of a resin cement to a composite used for inlay/onlay restorations.


METHODS
Forty-two blocks (6 x 6 x 4 mm) of a microfilled composite (Vita VMLC) were produced and divided into 3 groups (N = 14) by composite surface conditioning methods: Gr1--etching with 37% phosphoric acid, washing, drying, silanization; Gr2--air abrasion with 50-lm Al203 particles, silanization; Gr3--chairside tribochemical silica coating (CoJet System), silanization. Single-Bond (one-step adhesive) was applied on the conditioned surfaces and the two resin blocks treated with the same method were cemented using RelyX ARC (dual-curing resin cement). The specimens were stored for 7 days in water at 37 degrees C and then sectioned to produce nontrimmed beam samples, which were submitted to microtensile bond strength testing (muTBS). For statistical analysis (one-way ANOVA and Tukey's test, alpha = 0.05), the means of the beam samples from each luted specimen were calculated (n = 7).


RESULTS
muTBS values (MPa) of Gr2 (62.0 +/- 3.9a) and Gr3 (60.5 +/- 7.9a) were statistically similar to each other and higher than Gr1 (38.2 +/- 8.9b). The analysis of the fractured surfaces revealed that all failures occurred at the adhesive zone.


CONCLUSIONS
Conditioning methods with 50-lm Al203 or tribochemical silica coating allowed bonding between resin and composite that was statistically similar and stronger than conditioning with acid etching.
Valandro
Luiz Felipe
LF
Department of Restorative Dentistry, School of Dentistry, Federal University of Santa Maria, Brazil. lfvalandro@hotmail.com
Pelogia
Fernanda
F
Galhano
Graziela
G
Bottino
Marco Antonio
MA
Mallmann
Andre
A
D000134:Acid Etching, Dental; D000268:Adhesiveness; D000537:Aluminum Oxide / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D045662:Dental Etching; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D007284:Inlays; D008422:Materials Testing; D010756:Phosphoric Acids / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C448319:ESPE bonding system; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D012821:Silanes; C115612:single bond; D014867:Water; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; C030242:phosphoric acid; D000537:Aluminum Oxide