RESUMO
AIM: The aim of this in vitro study was to evaluate the diametral compressive bond strength between Charisma or TPH composite resin after association or not to an adhesive system in incremental filling technique. METHODS: Twenty cylinders of each composite resin brand were fabricated using a Teflon matrix and divided into four groups, according to the numbers of adhesive layers applied: group 1 Control without adhesive; group 2 one layer; group 3 two layers and group 4 three layers. The bonding system Adper Single Bond was used between composite resin increments. Diametral compression assays were carried out in an EMIC-MEM 2000 universal testing machine, adjusted at 1 mm/min. ANOVA and Tukey's test were used in the statistical analysis. RESULTS: The mean strengths and standard deviations for each group were: Charisma 1= 38.26+/-2.38; 2=46.56+/-2.38; 3=40.57+/-2.38; 4=36.87+/-2.38 (2>1=3=4; P<0.05) and TPH 1=52.17+/-2.38; 2=52.23+/-2.38; 3=44.68+/-2.38; 4=44.11+/-2.38 (1=2>3=4; P<0.05). CONCLUSIONS. It was concluded that TPH presented higher means of compressive bond strength than Charisma, and the association of an adhesive system between the increments may influence the diametral compressive bond strength of composite resins.