Enamel cracks in debonded, debanded, and orthodontically untreated teeth.

Using fiber-optic transillumination, a clinical assessment was made of enamel cracks (prevalence, localization, expression, direction) in three groups of adolescents representing debonded, debanded, and orthodontically untreated teeth. The findings indicated that enamel cracks were extremely common in all three groups. Most cracks were not very prominent and could easily be overlooked on routine clinical examination. The majority of cracks were vertical and, with the exception of the mandibular incisors, were most frequently localized in the gingival two-thirds of the facial tooth surfaces. The marked cracks were observed mostly on maxillary canines and central incisors in all groups. Of the few horizontal cracks noted, most were located in maxillary and mandibular central incisors. Clinical implications of the observations are (1) careful bonding and debonding do not result in a significant increase of enamel cracks; (2) whenever pronounced vertical cracks occur on other teeth than maxillary central incisors and canines or many horizontal cracks are observed, the bonding/debonding technique should be re-evaluated; (3) it seems advisable to notify parents/patients of marked cracks before orthodontic treatment is started, in order to avoid problems later when it is difficult or impossible to document their pretreatment existence.