Surface morphological changes in human enamel following bleaching: an in vitro scanning electron microscopic study.

OBJECTIVE The purpose of this study was to evaluate, using scanning electron microscopy (SEM), the morphological and structural changes of the enamel induced by three bleaching agents namely old McInnes solution, modified McInnes solution and 10% carbamide peroxide gel at different time intervals. MATERIALS AND METHODS Fifteen freshly extracted noncarious human central incisors with intact enamel surface were selected. The teeth were sectioned at the cementoenamel junction separating the crown portion from the root using a diamond separating disk. Following this, the samples were subjected to three different bleaching agents: Group 1: Old McInnes solution, group 2: modified McInnes solution and group 3: 10% carbamide peroxide for a period of 15, 30 and 60 minutes, 24 and 30 hours time interval. The sample stubs were subjected to scanning electron microscope and were photographed at 2000 and 10,000 magnifications. CONCLUSION The present study revealed no indication of either etching or significant change in surface morphology of enamel when evaluated under scanning electron microscope after 6 weeks treatment with various bleaching agents. CLINICAL SIGNIFICANCE Morphological alterations in bleached enamel are both concentration and time dependent.