253 milk teeth with inflamed gingiva were observed for 19 months (on average) around the time of exfoliation and changeover to the secondary dentition. The criteria used were the gingival index by Löe and Silness, the intravital staining of glycogen with iodine solution by Zabinska and the plaque index by Quigley and Hein. In about one third of the cases, there was residual inflammation following loss of the milk teeth in the original area. With eruption of the permanent teeth, plaque level increased as did the degree of gingival inflammation. On full eruption of the permanent dentition the values fell under their former level.