Mandibular intercanine width increase without intervention in children with slipped contacts

Imperfect spacing between the primary incisors and mal-alignment of the permanent incisors may suggest the need for orthodontic intervention. Without sufficient data, decisions to treat are based on individual judgment rather than evidence. The present study was undertaken to determine whether slipped contact arrangement (distal-lingual surface of mandibular permanent lateral incisors overlapping the facial surface of the primary canines at the end of incisor transition) merits intervention.

Seventeen children who presented with slipped contact arrangement between 1987 and 1991 were studied prospectively. Orthodontic records were gathered at enrollment and following eruption of full permanent dentition with the final record being obtained in 1995. Orthodontic characteristics were recorded and mandibular anterior teeth were measured for amount of slippage, available space and differences between primary and permanent intercanine width. Data were analyzed using student's paired t-test and other tests of statistical significance.

Mean mandibular intercanine width increased significantly at the emergence of permanent canines (2.58 mm; p=0. 001). Average slipped contact was 3.21 mm; average space deficiency between primary canines for ideally aligned permanent incisors was 3.54 mm. No correlation was found between intercanine width measurements and molar relationships, skeletal relationship, facial type or other orthodontic characteristics.

Slipped contacts should be considered when children undergo early orthodontic treatment for crowding. An explanation of the transitional correction is provided. Continued research is needed in this area to establish evidence-based early treatment parameters.