Resumo

SARTORI, Neimar; MONTEIRO JUNIOR, Sylvio; GONDO, Renata  e  BACKER, Mirian Marly. Evaluation of bonding strength of composite resin restoration repairs. Arq. Odontol. [online]. 2010, vol.46, n.4, pp. 190-196. ISSN 1516-0939.

Composite resin repairs can prevent the replacement of worn restorations. This study evaluated the influence of different surface treatments and bonding agents on the bonding strength between an aged composite resin restoration and its repairs. Thirty composite resin cubes (A3) with 64mm³ were constructed, artificially aged (5000 cycles of thermocycling), and randomly assigned into three groups: G1 -phosphoric acid etching; G2 - roughing with a diamond bur and phosphoric acid etching; G3 - sandblasting with aluminum oxide and phosphoric acid etching. Each group was subdivided into 2 subgroups according to the adhesive system applied: Adper Scotchbond MP_(BO) or Adper Single Bond 2_(SB). All experimental groups received a resin composite restoration in three increments (WE). Moreover, a control group was prepared in which Arquivos em Odontologia these increments were inserted directly over the un-aged composite resin. All cubes were stored in distilled water at 37ºC for 24 hours and were then sectioned longitudinally along the X and Y axes to obtain sticks (0.64mm²) for micro tensile bond strength testing (mTBS). In addition, a sample of each group was prepared to evaluate surface alteration using a scanning electron microscope (SEM). The data of bond strength was analyzed by a two-way ANOVA followed by Tukey HSD and Dunnett post-hoc tests (α = 5%). The mean bond strength values and standard deviation in MPa were: G1_(BO):60.1±9.2; G1_(SB):48.8±21.7; G2_(BO) :64.4±13.5; G2_(SB):64.5±9.0; G3_(BO):76.9±14.5; G3_(SB):72.6±13.9; and Control: 75.6±13.1. Regardless of the bonding agent, surface mechanical treatment is essential for the success of this procedure.

Palavras-chave : Operative dentistry; Dentin-bonding agents; Composites resins.