An in vivo study to determine the range of posterior teeth disclusion on working side in canine-guided occlusion.

Background And Objectives: This study was done with the objectives to determine the range of functional zone between the intercuspal positions and edge to edge position, the range of incomplete and complete disclusion of posterior teeth in canine-guided occlusion, and to have a gender comparison and comparison between right and left sides of the obtained values.

Materials And Methods: Thirty-five subjects showing canine-guided occlusion and Angle's class I canine and molar relation were chosen for the study. Maxillary midline and a corresponding line on the mandible were marked in maximum intercuspation with marker pen in the patient's mouth. Lines from 1 to 5 mm were marked on maxillary central incisor with marker pen. A dental floss was looped around the distal surface of mandibular last molar and the subject was asked to make left lateral movement (working side) at 1-mm intervals. The point at which floss was freed posteriorly was considered as initial disclusion and the point at which edges of maxillary and mandibular canines contacted was considered as complete disclusion.

Results: Most of the male and female subjects in the study showed progressive disclusion on right side and delayed disclusion on left side. The range of complete disclusion was 3-4 mm in males and 2-3 mm in females irrespective of the side. The range of functional zone was 1-4 mm irrespective of side or gender.

Interpretation And Conclusion: There is a need to redefine canine guidance in terms of immediate disclusion, delayed disclusion, and progressive disclusion.