ABSTRACT
Upper canine protects molar teeth from occlusal trauma by controlling lateral movement of mandible and discluding. Hence, it is expressive to find relative position between lingual contour of upper canine and lower canine. The authors have investigated relative position between clinical crown of upper and lower canine with rectangular coordinates system established on the trace in a labiolingual section of clinical crowns of upper and lower canine. As a result, the authors arrived at the following conclusion: 1. Significant difference between right and left side wasn't found in relative position between upper and lower canine clinical crown (p less than 0.05). 2. Items of upper canine hadn't relevance to items of lower canine. 3. Over bite had significant relevance to 4, 6, and 7. But overjet hadn't relevance to the other items.
