[Color distribution of the anterior teeth in 137 elder people]

To study the color distribution of the anterior teeth in elder people.

612 anterior teeth from 137 people aging from 60 to 81 years and 200 anterior teeth from 100 young people aging from 20 to 40 years were collected. A digital colorimeter was used to measure the value of L*,a*,b* of the teeth, and the chromatism (deltaE) was calculated according to the formula deltaE=(deltaL*(2)+deltaa*(2)+deltab*(2))1/2. All data were analyzed with SAS 6.12 software package for Student's t test.

Totally, there were 612 vital anterior teeth from elder people, including 201 central incisors,199 lateral incisors and 212 canines, were collected. No difference was found between the teeth on the right side and the left side in terms of L*,a*,b*value(P>0.05). The mean value of L*,a*,b* of the central incisors was 71.2+/-6.22,0.97+/-1.12,15.9+/-5.04, respectively and that of the lateral incisors and the canines were 69.6+/-5.52,0.6+/-1.18,13.9+/-4.15 and 68.4+/-5.99,0.15+/-1.02,19.6+/-4.87, respectively.The mean value of L*,a*,b* of the central incisors and the canines from the youngster was 75.82,-0.11,12.68 and 72.07,1.22,17.92, respectively.There were significant differences between the central incisors and the lateral incisors as well as the canines (P<0.05) in terms of L* value. Meanwhile difference was also found among the incisors and the canines in terms of a* and b* value(P<0.05). The deltaE between the central incisors and the lateral incisors was 2.945NBS, and the value between the canines and the central incisors as well as the lateral incisors was 4.629NBS and 5.832NBS, respectively, indicating that the color difference could be perceived visually. Compared to the youngster, the teeth of the elder people demonstrated a lower L* and a* value, but a higher b* value (P<0.05).

Among elder people, the central incisors look much brighter than the lateral incisors and canines, while the canines have more redness and yellowness than the incisors, and the color of the lateral incisors exhibits lighter than the central incisors and the canines. Compared to the teeth from younger people, the teeth from elder people look much darker and yellower but less red. Supported by Shanghai Leading Academic Discipline Project (Grant No.T0202).