The Ankylosed Tooth

Abstract

1. Tooth ankylosis, the fusion of bone and cementum, is a progressive anomaly of tooth eruption, profoundly affecting occlusion. 2. Deciduous teeth become ankylosed far more frequently than do permanent teeth, the ratio being better than 10 to 1, and lower teeth are ankylosed more than twice as often as upper teeth. 3. Tooth ankylosis exhibits selectivity as to site (nearly all ankylosed teeth are molars, deciduous or permanent) and selectivity as to physiologic time (nearly all ankyloses occur in the deciduous or mixed dentitions). 4. Tooth ankylosis is not likely to be of random or accidental origin, nor is excessive or traumatic pressure a probable cause although the latter enjoys wide acceptance. Tooth ankylosis may be due to a disturbance of metabolism. 5. Treatment depends upon whether the ankylosed tooth is deciduous or permanent, the time of onset, the time of diagnosis, and the location of the affected tooth. The determining criterion as to whether an ankylosed tooth is to he removed or not is the growth potential remaining; the greater this remaining potential , the more advantageous the immediate removal. This decision requires promptness because of the progressive character of the ill effects flowing from tooth ankylosis. There are six possible situations: If the ankylosed tooth is deciduous and has a successor, the general rule is to extract immediately and, if necessary, to insert an appropriate space maintainer until the successor emerges. If the tooth is deciduous and without a successor and the onset is early so that “submergence” is threatened, treatment includes extraction and space maintenance. If the tooth is deciduous and without a successor and the onset is late, proximal and occlusal contacts may be built at maturity. If the ankylosed tooth is permanent and the onset is early, the tooth should be luxated. If repeated luxation proves ineffective, the tooth should be extracted. It must not be permitted to “submerge.” If the onset of ankylosis is late, the permanent tooth should be luxated. If the attempt is unsuccessful and the tooth does not “submerge,” it may be built up at maturity. A deeply “submerged” ankylosed tooth, deciduous or permanent, should be left undisturbed unless it is infected or constitutes an immediate or potential threat to the occlusion. I gratefully wish to acknowledge that many of the illustrations are from the files of the New York University Orthodontics Department, made available through the kindness of the Chairman, Professor Samuel Hemley. Nearly all have previously appeared in the American Journal of Orthodontics and are reproduced with the kind permission of the C. V. Mosby Company.