[Bond strength of composite resin bonded to deciduous and permanent dentin]

The purpose of this in vitro investigation was to determine the shear bond strength (SBS) of composite resin bonded to deciduous (D) and permanent (P) dentine using the Scotchbond Multi-Purpose system (SMP, 3M). Twenty extracted, sound permanent human molar teeth (Group A) and twenty carious primary molars (Group B) were used in this study. All samples were ground wet on a polishing machine (220 grit) in order to expose superficial buccal dentine surfaces. Dentine surfaces were treated with the Scotchbond Multi-Purpose system according to manufacturers instructions. Z100 composite stubs were bonded to the treated dentine surfaces using a silicone rubber split mould. Bonds were stressed to failure in an Instron using a shear load. Data were calculated and analysed statistically (Student-t test). The mean SBS in MPa were 17.12 +/- 3.71 to deciduous and 23.60 +/- 2.47 to permanent dentine. SMP demonstrated a statistical higher (p < 0.01) shear bond strength to permanent than to deciduous dentine.