Periodontal ligament injection: distribution of injected solutions.

In a simulation of the clinical technique, a radiopaque solution and a colloidal carbon suspension were injected into the periodontal ligament in dogs by means of a standard syringe. The colloidal carbon method was superior and demonstrated that the injected material was found in soft tissue and adjacent hard structures and in the vessels of the pulps of the immediate and adjacent teeth. The distribution of the dye did not relate to the injection volume and needle location but was consistently more widespread when injections were given under moderate to strong pressure. The technique appears to be a form of intraosseous injection.