Optimal parameters for final position of teeth in space closure in case of a missing upper lateral incisor.

BACKGROUND: The aim of this study was to provide clinical indications for the correct management of appliances in space closure treatment of patients with agenesis of the upper lateral incisors. METHODS: Virtual setup for space closure was performed in 30 patients with upper lateral incisor agenesis. Tip, torque and in-out values were measured and compared with those of previous authors. RESULTS: In the upper dentition, the tip values were comparable to those described by Andrews (Am J Orthod 62(3):296-309, 1972), except for at the first premolars, which require a greater tip, and the first molars, a lesser tip. The torque values showed no differences except for at the canines, where it was greater, and the in-out values were between those reported by Andrews and those by Watanabe et al. (The Shikwa Gakuho 96:209-222, 1996) (except for U3 and U4). CONCLUSIONS: The following prescriptions are advisable: tip 5 degrees , torque 8 degrees and in-out 2.5 for U1; tip 9 degrees , torque 3 degrees and in-out 3.25 for U3; tip 10 degrees , torque -8 degrees and in-out 3.75 for U4; and tip 5 degrees , torque -8 degrees and in-out 4 for U5. Andrews' prescription is suitable for the lower jaw, except for at L6. It is also advisable to execute selective grinding (1.33+/-0.5 mm) and extrusion (0.68+/-0.23 mm) on the upper canine during treatment, and the first premolar requires some intrusion (0.56+/-0.30 mm).