The Morphology Of Young Maxillary First Premolar And Its Clinical Significance

The premolar has the characteristics of both incisor and molar as far as morphology and function are concerned, so it of clinical significance to study the teeth. It also can be collected easily for orthodontic treatment, and the intact tooth is good for the measurement and observation, which was almost extracted from young people. In this study, we observed and measured and calculated the external and internal morphology of the roots of young maxillary first premolars in Jiangsu province' population by many techniques. In addition, we connected clinic and investigated the effects of tooth anatomy on root canal therapy difficulty and evaluated the accuracy of two-dimensional technique and the feasibility of three-dimensional reconstruction techniques in studying of root and canal morphology. So, we hope that we will offer helpful data to clinical root canal therapy.Part One: Morphologic Research1 Crown and root measurementsMaterials and Methods: One hundred and thirty six recently extractedmaxillary first premolars were used. The span, crown and root length,mesiodistal widths / buccolingual thickness of crown and cervical and rootmiddle point were measured by a sliding caliper. And linear correlation andlinear regression of the measurements were analyzed.Results: Obvious positive correlations including of crown /root length andspan, mesiodistal widths / buccolingual thickness of crown and cervical androot middle point (P < 0.01) . Statistically significance was found when usecervical mesiodistal width to calculate mesiodistal width of root middle point,...