Microtensile bond strengths of composite to dentin treated with desensitizer products.
OBJECTIVE
This study was designed to analyze the influence of desensitizing procedures on dentin bond strength.


METHODS
Forty bovine incisors were used, divided into four groups (n = 10): G1: control; G2: Gluma Desensitizer (Heraeus Kulzer); G3: Oxa-Gel (Art-Dent); G4: low-intensity laser (MMOptics). The buccal surface was wet ground flat with 180-, 400- and 600-grit silicon carbide abrasive paper to expose midcoronal dentin and create a uniform surface. After the application of the desensitizing agents to the exposed dentin, the specimens were etched with 35% phosphoric acid for 30 s, and an adhesive (Single Bond) was applied and light cured. A 4-mm high crown of composite resin (Filtek Z250) was then built up. Specimens were trimmed to an hourglass shape with cross sections of 1 mm2. Each specimen was individually fractured by a microtensile testing machine at a crosshead speed of 0.5 mm/min. The data, recorded in MPa, were analyzed with one-way ANOVA and the Duncan test (p = 0.05).


RESULTS
Specimens treated with dentin desensitizers (except Gluma) yielded significantly lower mean bond strengths than nontreated control specimens. The mean values in MPa (+/- SD) were: G1: 13.4 (6.2); G2: 13.2 (4.8); G3: 7.15 (4.3); G4: 7.21 (4.6).


CONCLUSIONS
Among the desensitizing agents studied, only Gluma Desensitizer did not detrimentally influence the bond strength values. It is a useful material for dentin desensitization.
Aranha
Ana Cecília Corrêa
AC
Department of Dentistry, Special Laboratory of Lasers in Dentistry, University of São Paulo, Brazil. acca@usp.br
Siqueira Junior
Adonis De Santi
Ade S
Cavalcante
Larissa Maria Assad
LM
Pimenta
Luiz André Freire
LA
Marchi
Giselle Maria
GM
D000134:Acid Etching, Dental; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D002482:Cellulose / Q000031:analogs & derivatives / Q000627:therapeutic use; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003804:Dentin / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure*; D003807:Dentin Sensitivity / Q000188:drug therapy* / Q000532:radiotherapy; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005976:Glutaral / Q000627:therapeutic use; D007834:Lasers; D008422:Materials Testing; D008689:Methacrylates / Q000627:therapeutic use; D008855:Microscopy, Electron, Scanning; D010070:Oxalates / Q000627:therapeutic use; D010756:Phosphoric Acids / Q000737:chemistry; D013499:Surface Properties; D013718:Tensile Strength
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D008689:Methacrylates; D010070:Oxalates; D010756:Phosphoric Acids; C111486:gluma desensitizer; C470050:oxa-gel; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; D002482:Cellulose; C030242:phosphoric acid; D005976:Glutaral