SEM study of different treatments of the smear layer on different cavity walls.

The present study evaluated the effects of slightly demineralizing treatments on dentinal cavity walls, since some recently developed adhesive procedures are applied over the smear layer. Ten experimental treatments--mechanical, chemical or mechanical/chemical--were applied on MOD cavity walls prepared in vitro with diamond burs. The dentinal surface of a lateral and of a pulpal wall of each cavity was evaluated through scanning electron microscopy, and the effects of the treatments were compared. All treatments except air/water spray removed some of the smear layer, and slight differences were observed regarding the studied cavity walls: on dentin from pulpal walls the enamel hatchet associated with tannic acid produced a better effect than the other treatments, and on dentin from lateral walls the biological detergent rubbed with cotton pellets was a little more effective than the other treatments. The effect of the smear layer treatment on dentin is different according to the wall and to the applied treatment.