Evaluation of the use of orthodontic records to measure the width of keratinized tissue.

Understanding the gingival tissue response in patients undergoing orthodontic treatment requires accurate pretreatment measurements of the width of the attached and keratinized tissue. Even though these may not be routinely recorded, it has been suggested that the orthodontic records can provide an accurate method of assessing the pretreatment keratinized tissue width. This clinical study was conducted to compare measures of the width of the keratinized tissue calculated from intraoral photographs and study models with direct clinical measures. Maxillary and mandibular study models and intraoral photographs were obtained from 33 patients. The width of the keratinized gingiva facial to the mandibular incisors was measured on two occasions to the nearest 0.5 mm. The width of the gingiva was calculated for the same teeth from two measures taken from projected photographic slides and the study models using a modification of Coatoam's technique. The method error was determined to be 0.43 mm for clinical measures and 0.32 mm for the calculated gingival tissue width. The reliability of measurement from orthodontic records was slightly greater than direct clinical measurement, with intraclass correlations of 0.93 and 0.90, respectively. The differences between the averaged clinical measure and averaged calculated measure for each tooth were small and not statistically significant (paired t-test, P = 0.21, 0.66, 0.24, 0.24 for teeth 23 through 26 respectively). The results indicate that carefully taken photographic slides and study models can provide an accurate measure of keratinized tissue width.