OBJECTIVETo investigate the stimulation of Cinnamaldehyde to the pulp tissue and the periapical tissue of rats' teeth, to provide evidence for developing Cinnamaldehyde as a pulp-cap of pulpotomy in primary teeth.

METHODSUsing Cinnamaldehyde as pulp-cap in pulpotomy of rats' teeth, set up Cinnamaldehyde group, formaldehyde cresol formocresol group and blank group. After different treatment according to the empirical procedure, rats were killed in the 4th week and on the 12th week. Then the experiment teeth and the periodontal tissue were made into HE slides and observed using light microscope.

RESULTSThe 4" week, internal absorption, external absorption, and calcification were of no significance among all the groups. Inflammation in blank group was far more severe than that in other two groups (P<0.05), while the latter two were of no significance. The 12th week, internal absorption, external absorption, and inflammation between the former two groups were of no differences, but the indexes were significantly different from them of the blank group (P<0.005). Calcify was not obvious in all the slides.

CONCLUSIONAs a pulp-cap, Cinnamaldehyde stimulates the pulp tissue and the periapical tissue at a very low level. The research provides histopathology rationale for Cinnamaldehyde as pulp-cap of pulpotomy in primary teeth.