Tissue reactions to two root canal sealers containing formaldehyde.

Tissue reaction to root fillings using either Endomethasone or N2 was investigated in the premolar teeth of dogs. Periapical inflammation was frequently observed, but of greater significance was the universal evidence of ankylosis and the accompanying resorption of teeth filled with N2. One tooth filled with Endomethasone also exhibited this condition. The results of this study do not support the use of these root canal sealers that contain formaldehyde.