Role of Prostaglandins on Resorption of Deciduous Teeth during Teeth Exchange in Rabbits

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The study aimed to confirm whether PGE2 had any connection with physiological root resorption. My previous study showed that resorption of deciduous upper incisors in rabbits started on the 9th day postnatally and that the resorption occured in 3 stages : (1) early stage (9-13 days), where there was active resorption by odontclasts ; (2) resting stage (15-21 days) ; and (3) final stage (23-25 days), where resorption reoccured by odontclasts and inflammatory ceels. For this study, 64 young rabbits used. The control groups were injected with normal salin, and the treatment groups were injected with 10.0 mg/kg indomethacin at 9hr and 3hr before sacrifice. The maxillae were excised, and the root-resorbing tissue (RRT) were carefully removed and the PGE2 level of them were measured by RIA using [^<125>I] PGE2-RIA kit at 5,9,13,17,21 and 25 days, respectively. Additionally, the level of PGE2 of the oral mucosa of hard palate (OMP). The resuls were as follows :The concentration of PGE2 (mean<plus-minus>S.D.pg/mg wet.tiss.) of RRT in control groups were 446<plus-minus>419 at 5 days, 3751<plus-minus>2454 at 9 days, 748<plus-minus>504 at 13 days, 180<plus-minus>19 at 17 days, 253<plus-minus>128 at 21 days and 1520<plus-minus>398 at 25 days, and those of OMP in control groups were 87<plus-minus>98 at 5 days, 242<plus-minus>377 at 9 days, 25<plus-minus>18 at 13 days, 60<plus-minus>47 at 17 days, 362<plus-minus>131 at 21 days and 1168<plus-minus>1164 at 25 days, respectively. PGE2 levels at 9,13 and 25 days were greater than at 5,17 and 21 days in control groups (p<0.05). PGE2 in RRT was higher at 9 and 13 days than in OMP (p<0.05). Except at 5 days, PGE2 in treatment group was always lower than in control group, in both RRT and OMP (p<0.05). These results strongly suggest that PGE2 can possibly act as a chemical mediator of odontoclasic root resorption occurr