As a method of age estimation from teeth we focused our attention on attritions of lower incisors. Using the Amano's method, we took records of tooth attritions in the planted state of 83 subjects whose ages ranged from 14 to 76 years. A positive correlationship was found to exist between the tooth attrition index and the actual age, allowing to establish the following formula which graphically shows a straight line: Y = 8.505X + 26.073 (r = 0.607), where X is the mean of attrition indexes of lower incisors and Y, the estimated age. In our method of age estimation through attrition indexes, we took advantage of probability and confidence interval. In addition, our method was contrasted with Amano's method, a widely used one in Japan.