A 3-year clinical and SEM study of surface changes of carious enamel lesions after inactivation

The surface features of incipient carious lesions around bonded orthodontic brackets were assessed during a 3-year period after appliance removal. At standardized intervals color slides and silicone impressions for replication were made of two maxillary incisors on each of six adolescent patients. The labial surfaces of the teeth had demineralized white areas around the bonded brackets. The color slides were projected and studied in a darkroom. The positive surface replicas were studied by scanning electron microscopy (SEM). At the time of debonding, large accumulations of dental plaque were observed in those areas with white, demineralized surfaces. During the posttreatment or experimental period, there was a reduction in the amount of plaque. The appearance of the lesions changed from chalky-white at time of debonding to a more diffuse opacity, particularly in the peripheral parts. Under SEM the surfaces of the lesions were less irregular 3 years after debonding. At higher magnification the labial surfaces showed signs of wear. The present study confirms that removal of cariogenic challenge results in arrest of further demineralization. The gradual regression of the lesion at the clinical level is believed to be primarily a result of surface abrasion.