Study on the mechanism of discoloration and the efficacy of bleaching in non-infected traumatically discolored teeth / 中华口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the mechanism of discoloration and the efficacy of bleaching in non-infected traumatically discolored teeth.</p><p><b>METHODS</b>In vitro model of discolored teeth sample of fresh erythrocytes was placed in the pulp cavity of 20 extracted teeth and centrifuged for 3 consecutive days. These discolored teeth were divided equally and randomly into two groups group A (control group); group B (bleaching group), bleached with 10% carbamide peroxide gel for 4 weeks. And then all teeth were prepared for histological examination and subjected to a series of histochemical tests to analyze some of the biochemical changes following haemorrhage into the pulp chamber and post-bleaching.</p><p><b>RESULTS</b>Haemoglobin and haematin were detected in the dentinal tubules of discolored teeth from group A and no evidence of ferric or haemosiderin. Specimens from group B demonstrated a negative response to histochemical tests.</p><p><b>CONCLUSIONS</b>In the absence of bacterial invasive, haemoglobin and haematin could cause discoloration of non-infected traumatized teeth. Peroxide bleaching agent can effectively remove haemoglobin and haematin.</p>