Alveolodental ankylosis induced by root canal treatment in rat molars

Abstract

Alveolodental ankylosis induced by root canal treatment was studied in 253 60-day-old albino rats. Zinc oxide—eugenol, Grossman cement, and formaldehyde-containing cements, as well as pastes containing formalin, trioxymethylene, and trioxymethylene-prednisolone-acrylic spherules, were used as root canal filling materials. Ankylosis produced by either ZOE or Grossman cement was rare and was limited to the periapical area. Formaldehyde-containing cements caused severe and frequent partial ankylosis at different levels of the periodontal ligament. Total ankylosis was found in some cases. Pure formalin and 50 per cent formalin solution produced extended or total ankylosis 30 days after treatment. Trioxymethylene produced extended alveolar bone necrosis and an acute inflammatory tissue reaction. Rats treated with trioxymethylene-corticoid and acrylic spherule paste exhibited two types of tissue reaction: 1. 1. An ankylotic reaction appearing either 30 or 90 days after treatment, following cementum, periodontal ligament, and alveolar bone necrosis. 2. 2. An inflammatory reaction affecting the necrotic periodontal ligament, occasionally accompanied by huge sequestra and an encapsulating fibrous reaction.