The bond strength of a glass polyalkenoate cement after chemomechanical
caries removal of dentine with or without the use of a conditioning
agent and the mode of bond failure using scanning electron microscopy
was examined. Forty extracted carious human teeth were divided into
four groups of ten. Conventional caries removal was carried out on two
groups and chemomechanical caries removal on the other two groups.
Surface conditioner was applied to the dentine in one conventionally
treated and one chemomechanically treated group. Glass polyalkenoate
cement was applied via a metal holder to the dentine. The samples were
stored for 7 days in a moist environment at 37 degrees C. The samples
were subjected to a shearing-type stress at a cross-head speed of 0.5
mm min(-1). The mean bond strength for each group, in MPa (standard
deviation), was: conventional caries removal alone 1.32 (0.51),
conventional caries removal and conditioner application 2.43 (0.47),
chemomechanical caries removal alone 2.47 (0.99) and chemomechanical
caries removal and conditioner application 2.76 (0.96). Mean bond
strengths for both the chemomechanically treated groups and the
conventionally treated group, coupled with the use of the conditioning
agent, were significantly greater than for the conventionally treated
groups alone at the 0.05 level. There was no significant difference
between the chemomechanically treated groups or the group
conventionally treated with conditioner application. SEM examination
revealed a combination of cohesive and adhesive bond failure. Different
morphologies between the conventionally and chemomechanically treated
surfaces were also evident.