Estimation of the rate of tooth wear in permanent incisors: A cross-sectional digital radiographic study

This study used conventional digital radiography to estimate the rate of tooth wear (TW) of maxillary and mandibular central incisors based on a cross-sectional study design. The crown length of 1239 permanent maxillary and mandibular central incisors from 346 persons (age groups: 10, 25, 40, 55 and 70 years ±3) were measured by three calibrated dentists. Study teeth were intact incisally, had clearly visible incisal edges and cementoenamel junctions and had natural tooth antagonists. Measures were based on digital radiographic images (N = 666) archived in MiPACS within the electronic health record (axiUm®) from the College of Dentistry patient database. Incisor crown length decreased at a linear rate in both arches over the 60 years represented by the age groups. The average crown length for maxillary incisors in the youngest age group was 11·94 mm, which decreased by an average of 1·01 mm by median age 70. For mandibular incisors, the average crown length in the youngest age group was 9·58 mm, which decreased by an average of 1·46 mm in the oldest age group. Males and females showed similar rates of TW. Regardless of age, females demonstrated smaller mean crown height for maxillary incisors than males (P < 0·0001). Measures by the examiners demonstrated good agreement, with an interclass correlation coefficient of 0·869 and an average intra-examiner correlation of 99·5%, based on repeated measurements (n = 100). TW was estimated to average 1·01 mm for maxillary central incisors and 1·46 mm for mandibular central incisors by age 70 years.