A new design for space maintainers replacing prematurely lost first primary molars.

Studies of the developing anterior occlusion in the mixed dentition indicate a physiologic distal and labial repositioning of the primary canines concomitant to eruption of the maxillary and mandibular permanent incisors. In order not to impede these canine movements, a modification of the loops of bandloop space maintainers is recommended. In place of the usual concavity which encircles the distal surface of the canine crown, a distolabial slope is incorporated into the anterior portion of the loop. This revised design will allow the canine to migrate labially and distally while simultaneously preventing loss of arch length necessary for the unerupted first premolar. In addition, arch space required for eruption and alignment of permanent labial incisors can be preserved. Space maintainers frequently are recommended to preserve arch space resulting from premature loss of first primary molars. Changes occurring in the developing anterior occlusion during mixed dentition require that the space previously occupied by a prematurely lost first primary molar be maintained. This article will describe a modification of the design of first primary molar space maintainers based on growth changes occurring in the canine areas of the mixed dentition.