Study On The Mechanism Of Discoloration And The Efficacy Of Bleaching Of Traumatized Teeth

Objective: To investigate the mechanism of discoloration and the efficacy of bleaching of traumatized teeth.Materials and methods: Vitro model of discolored teeth: Sample of fresh erythrocytes was placed in the pulp cavity of 20 extracted teeth and centrifuged twice daily for 25 minutes over a period of 3 consecutive days.These discolored teeth were divided equally and randomly into two groups .The teeth of Group B were bleched internally and externally with 10% carbide peroxide gel for 4 weeks.The teeth of group A is control group. And then all teeth were prepared for histological examination and subjected to a series of histochemical tests: (1) benzidine, (2)zinc leuco, (3)Perl's and (4) Turnbull Blue to analyse some of the biochemical changes following haemorrhage into the pulp chamber and postbleaching.Results: 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.Conclusion: In the absense of bacterial invasive, it is haemoglobin and haematin that cause discoloration of traumatized teeth. Peroxide bleaching gel can effectively get rid of haemoglobin and haematin.