Evaluation of two reference planes to the horizon in the natural head position [electronic resource] /

by Allport, David M.

EVALUATION OF TWO REFERENCE PLANES TO THE HORIZON IN THE NATURAL HEAD POSITION By: David M. Allport, D.D.S. Dental casts are mounted to dental articulators using anatomical records in order to simulate and duplicate static and dynamic interocclusal relationships. The three dimensional relationship of the maxillary arch to the transverse horizontal axis of the mandible is defined by establishing a third point of reference. The most common reference plane is the Frankfort horizontal plane, which is theoretically parallel to the horizon when the patient is in the natural head position. 1 The HIP [hamular notch incisive papilla] plane has also been proposed as a true horizontal reference plane for orienting the maxillary cast to the articulator. 2 The purpose of this study was to examine the relationship of the Frankfort horizontal plane and the HIP plane to the horizontal when the patient is in the natural head position. Ten subjects were evaluated in the natural head position with angular measurements made from lateral photographs and lateral skull radiographs to determine the relationship of these two reference planes to the true horizontal plane. The mean, standard deviation and coefficient variation were calculated for both reference planes. The clinical significance of this information is to verify or modify those techniques used for mounting dental casts to the dental articulator, which is used in treatment planning and laboratory procedures. iii I would like to dedicate this research to my Grandfathers’ Orval Allport and Auston Crookshanks. Both these men dedicated their life working hard and taking care of their families. They mean so much to me personally and all of my accomplishments. Thank you, I love and miss you both. To my parents, Thank you for giving me every opportunity a son could ask for and the constant support and guidance that you have provided. You have influenced me more than you probably realize. You have given me the two most important things parents can give their children—roots and wings. iv