Root resorption after local injection of prostaglandin E2 during experimental tooth movement.

The purpose of this study was to investigate the occurrence of orthodontic root resorption in connection with local injection of prostaglandin E2 (PGE2). The material consisted of 25 male Wistar rats. The control group comprised six animals where no force was applied. In five animals 0.1 ml of 0.1 micrograms/microliter PGE2 was injected in the gingival area of the upper right first molar. In one animal no PGE2 was injected. The animals were killed after 3 days. The experimental tooth movement groups consisted of 19 animals. Duration of experiments was 3 days, 7 days, and 10 days. The maxillary first molars on both sides were each moved mesially by means of a coil spring. On the right side 0.1 ml of PGE2 0.1 micrograms/microliters was injected in the gingiva on the buccal side of the upper first molar on days 0, 3, 5, and 7. On the left side no injection of PGE2 was performed. In three animals in the 7-day group the vehicle (Waymouth medium) was injected. There was no significant difference in root resorption between the experimentally moved teeth with and without local injection of PGE2, but a trend towards more root resorption was registered on the teeth where such injections had been performed.