The effect of internal bleaching on tetracycline in dentin

By Lake, F.T., O'Dell, N.L., and Walton, R.E.

Date: 01/1985
Journal: JOE


Determine whether root canal treatment followed by internal bleaching altered the tertracycline incorporated into dog teeth.


N =3 Mongrel puppies

Puppies were given high does of demeclocycline 1 week after birth at regular intervals to stain their teeth. Then split into 3 groups A. Controls, untreated (eight teeth). These teeth received no treatment.

  1. Controls, root canal treated only (eight teeth). The chamber was filled with white temporary stopping and the access opening was sealed with an acid-etched composite restoration. C. Control, root canal treated without restoration (two teeth). D. RCT and walking bleach using sodium perborate and 30% hydrogen peroxide and repeated 1 week later. Material was then removed and replaced with a white filling and restored with composite. The Animals euthanized at 4 weeks and 25 weeks . Longitudinal block sections of whole individual incisor teeth and their supporting bone were removed, dehydrated in ascending concentrations of alcohol, and cleared. They were then sectioned into dentin discs and examined for fluorescence . The amount of TC in the teeth was estimated by measuring the intensity of TC fluorescence in the teeth.


Nontreated control teeth and root canal only teeth, when viewed with fluorescence microscopy, showed intense fluorescence in both the root and crown portions of the tooth

Root canal-treated and bleached teeth demonstrated an obvious reduction in fluorescence in the crown portion while fluorescence in the root was similar to that of the controls

Clinical Significance:

Bleaching agents placed in the chamber altered or removed the tetracycline.