[Prognosis for the deciduous molars of juvenile dogs after root canal filling using apatite root sealer].

There are various restrictions on the root canal filling of deciduous roots after root canal treatment unlike in the case of permanent teeth, because deciduous molars undergo physiological root resorption with aging. Among the restrictions, it is most important that the root canal filling material be similarly absorbed and disappear along with the deciduous root so that it does not prevent the eruption of the permanent successors. Hardly any of the root canal filling materials currently on the market, however, are suitable for deciduous molars because some of them disappear earlier than the deciduous root without becoming indurated in the root canal, while some delay tooth replacement because they are resorbed with great difficulty, and continue strongly to stimulate the surrounding tissue of the root apex. Root canal filling materials utilizing alpha-TCP and hydroxyapatite with excellent biocompatibility have recently been put on the market by Sankin Kygyo Co. Type-III, in particular, contains only 5% iodoform, causing only very slight stimulation, and is a relatively good product from a practical standpoint, i.e., filling the root canal using a lentulo. Root canal filling was performed immediately after dental pulp extraction from the deciduous mandibular molars of juvenile dogs to determine the feasibility of filling deciduous teeth with root canal filling materials. Three dogs were then observed for sequential changes in the resorption of the deciduous roots, presence/absence of adverse effects on permanent successors, and influence on the process of eruption by means of radiographic examination every week. The results obtained were as follows: 1. The type-III apatite root sealar or Vitapex used for root canal filling was not absorbed, and there was almost no resorption of the root. Thus, the deciduous teeth on the experimental side were ejected and shed. 2. There was no significant difference in the amount of tooth germ formed between the experimental and control sides. 3. The amount of eruption tended to be delayed because of insufficient resorption of the root of the deciduous predecessor, but this tendency was considered to be due to the influence of the timing of root canal filling and individual difference. In the final analysis, no definite conclusions could be drawn.