Overall, Liversidge and colleagues' method for age estimation of immature skeleton's by using developing tooth length was accurate. Only the deciduous maxillary canine and the permanent maxillary and mandibular second molars provided age estimates significantly different from true chronological age. Results also show that the combination of maxillary and mandibular teeth for developing regression formulas did not influence their differential performance, since age estimates did not differ between the upper and lower jaws; however, this was only true for the permanent dentition. Despite some of its problems and limitations, Liversidge and colleagues’ quantitative method of estimating age by tooth length has several advantages. It is specifically designed to estimate age; it is more objective than other methods; it can be easily applied on isolated teeth for the entire postnatal growth period; and sex did not have to be determined. Still, the author calls for further research into the overall performance of this method of age estimation, particularly regarding the results obtained from both jaws. The test sample consisted of 57 Portuguese subadult skeletons of known age at death. Developing mandibular and maxillary deciduous and permanent teeth were measured according Liversidge and colleagues’ method as the distance from the cusp tip to the developing edge of crown or root in the midline, parallel to the long axis of the tooth. In teeth with more than one cusp or root, the maximum length was measured. Measurements were taken on isolated teeth by using a standard digital caliper and recorded to the nearest tenth of a millimeter. 2 tables and 15 references