Evaluation of annual incremental lines of dental cementum is one of potentially valuable methods for biological age estimation in forensic anthropology. The objective of this work was to elucidate the relation between the number of those lines and the chronological age of an individual. Material of the study consisted of undecalcified sections of 227 permanent teeth of 178 individuals (89 males, 89 females, average age 47.5 years) (3-4 of each tooth, thickness 33-35 mum). Sections were analyzed under magnification of 20-40 times, photographed and evaluated using digitalized visual analysis system. Biological age was estimated by pooling the number of lines counted and the average age of tooth eruption. It was found that the number of lines strongly correlates with the chronological age (r>0.95, p<0.001). Factor of sex has no significant influence on the number of lines. Absolute average error was 5.58 years (11.75%), but the preciseness of the method decreases with age: among younger individuals it is lower - 3.71 years (10.09%), and higher among older - 7.86 years (13.1%). Regression power equation produces higher error than the traditional method: the best results are obtained by pooling the number of lines and average age of tooth eruption. Conclusion is made that the method is suitable for forensic anthropology, and digitalized system enhances the count and provides better results.