RESUMO
<p><b>OBJECTIVE</b>To investigate the effects of mineral trioxide aggregate(MTA) on the proliferation and differentiation of rat dental papilla cells(RDPC).</p><p><b>METHODS</b>RDPC were cultured by tissue block method and identified.RDPC of the third passage were cultured with material extract fluid containing different mass concentrations of MTA (0.002, 0.02,0.2, 2 and 20 g/L) for 3 d, those cultured with routine culture fluid served as control group. The proliferation-related parameters were measured by methyl thiazolyl tetrazolium(MTT) assay. RDPC were cultured with material extract fluids containing 0.002 g/L MTA, those cultured with routine culture fluid served as control group, the activity of alkaline phosphatase(ALP) at 1, 3,5, 7 d and the level of collagen I at 1, 3,5 d were detected.</p><p><b>RESULTS</b>MTT results showed that the A value of RDPC of group 20 g/L (0.092 ± 0.011) was less than that of the control group (0.249 ± 0.006) at 3 d(P < 0.01), the A value of RDPC of group 0.02 g/L (0.267 ± 0.005) and 0.002 g/L (0.276 ± 0.006) were more than that of the control group (0.249 ± 0.006) at 3 d(P < 0.01). ALP detection proved that ALP activity of MTA at 3 d (0.217 ± 0.008), 5 d (0.253 ± 0.005) , 7 d (0.279 ± 0.004) were more than that of the control group at 3 d (0.166 ± 0.006) ,5 d (0.221 ± 0.006), 7 d (0.242 ± 0.004) (P < 0.01). Collagen I detection showed that the level of collagen I of MTA at 3 d[(78.46 ± 2.72) µg/L], 5 d[(90.73 ± 3.08) µg/L] were more than that of the control group at 3 d[ (66.75 ± 3.08) µg/L], [5 d (74.27 ± 3.50) µg/L] (P < 0.01).</p><p><b>CONCLUSIONS</b>MTA of high concentrations can significantly inhibit cell growth, and of low concentrations can promote cells proliferation and differentiation.</p>
