Root resorption during Begg treatment: A longitudinal roentgenologic study

Abstract

Forty-two patients consecutively treated by the Begg method, all of whose first premolars had been extracted before orthodontic treatment, were examined roentgenologically by an intraoral technique on three to four occasions. The examinations were made before treatment, during treatment (before uprighting of tipped teeth), after completion of treatment, and 6 months after completion of treatment. In order to determine the occurrence and degree of root resorptions during the treatment period, a root resorption index was constructed. The reproducibility of the resorption index was studied by two observers. For assessment of the incidence and degree of root resorptions, the series of roentgenograms from each patient were examined simultaneously. The reproducibility of the simultaneous evaluation was also studied. In all of the forty-two cases treated, root resorption was recorded in the last roentgenologic examination. Before treatment small resorptions were found in 4 per cent of the teeth. Already, before uprighting of the tipped teeth, irregular root contours (score 1), probably caused by resorptions, and resorptions < 2 mm. (score 3) were recorded for 25 per cent and 31 per cent, respectively, of the teeth. There was no visible resorption in 42 per cent of the teeth. At the completion of treatment resorption < 2 mm. (score 3) predominated with 48 per cent, resorption of 2 mm.—one third of the root (score 5) occurred in 3 per cent, and no visible resorption occurred in 23 per cent of the teeth. When analyzing the percentage distribution of different degrees of root resorption in the teeth examined, we found that the relatively high frequency of root resorption before uprighting of tipped teeth increased slightly at completion of treatment. The resorption increased more for the upper central incisors, which were subjected to root torque, than for the upper lateral incisors. The incidence of root resorption 6 months after completion of treatment was highest at the lower central incisors (95 per cent). The upper central and lateral incisors showed an incidence of 90 and 87 per cent, respectively, and the lower and upper canines showed an incidence of 79 and 72 per cent, respectively. The lower premolars showed the lowest incidence of root resorption (53 per cent). The teeth that exhibited root resorption prior to treatment developed more resorption than the average during orthodontic treatment. This was especially marked for the upper incisors.