Loyola University Chicago Loyola eCommons Master's Theses Theses and Dissertations 1972 An Evaluation of Maximum Occlusal Force During the Initial Stages of Orthodontic Treatment Thomas Malcolm Stewart Loyola University Chicago Follow this and additional works at: https://ecommons.luc.edu/luc_theses Part of the Dentistry Commons Recommended Citation Stewart, Thomas Malcolm, "An Evaluation of Maximum Occlusal Force During the Initial Stages of Orthodontic Treatment" (1972). Master's Theses. 2522. https://ecommons.luc.edu/luc_theses/2522 This Thesis is brought to you for free and open access by the Theses and Dissertations at Loyola eCommons. It has been accepted for inclusion in Master's Theses by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. Copyright © 1972 Thomas Malcolm Stewart AN EVALUATION OF MAXIMUM OCCLUSAL FORCE DURING THE INITIAL STAGES OF ORTHODONTIC TREATMENT BY. THOMAS MALCOLM STEWART A THESIS SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF LOYOLA UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE JUNE 1972 ACKNOWLEDGEMENTS The author wishes to express sincere appr_eciation to all those individuals who contributed so much to the writing of this thesis. Gratitude is expressed to Dr. Douglas Bowman, who helped design the project and served as i~adviso~. His unselfish contribution of time and effort will always be remembered. Special thanks to Dr. Ravindra Nanda for his in- valuable guidance in- the preparation of the manuscript, and to Dr. Priscilla Bourgault for serving on the advisory board. Thanks to Dr. Donald c. Hilgers and the staff of the Department of Orthodontics for the opportunity to receive an orthodontic education, and to Dr. Gustav Rapp and Dr. John Madonia· for making graduate study possible. Warmest appreciation is expressed to my parents, without whose innumerable personal sacrifices I might not have attained an undergraduate education, and to Sharori and Susan whose, love, patience, and understanding have made it possible to realize the' goals of a graduate education. _____ ......, ____________ ~-~--------------------- BIOGRAPHY Thomas M. Stewart was born in Lebanon, Indiana, on February 19, 1939. After graduation from Lebanon High School in 1957, he completed one year o·f pre-dental curriculum at Wabash College, Crawfordsville, Indiana, and two years of pre- dental studies at the Ohio State University, Columbus, Ohio. He enrolled in the Ohio State University College of Dentistry in 1960 and received' the degree of Doctor of Dental Surgery in June, 1964. Following two years service with the U.S. Navy Dental f.: Corps, he entered general practice in Camarillo, California, for four years. In addition, he served as Assistant Clinical Professor in Operative Dentistry at the Center· for the Health Sciences, University of California. at Los Angeles, Los Angeles, California, from 1967 to 1970. In 1970 he left general practice to pursue a two year residency in Orthodontics and full time graduate studies in Oral Biology at the School of Dentistry, Loyola (Chicago) University, Maywood, Illinois. TABLE OF CONTENTS INTRODUCTION. .. 1 REVIEW OF THE LITERATURE. • • • • • • • 2 METHODS AND MATERIALS •.•••••••••••• 14 RESULTS OF EXPERIMENTATION . 21 DISCUSSION . .• • • • 27 SUMMARY AND CONCLUSIONS. • . • . • 37 BIBLIOGRAPHY • • • . • 39 APPENDIX . • 41 • p -1- INTRODUCTION AND STATEMENT OF THE PROBLEM Since the turn of the century, a substantial number of studies have been performed concerning the ability of humans to exert maximum occlusive force {bite force). These investigations have been conducted on normal healthy, restored, and edentulous artificial dentitions. Recently, a few studies have related the function of the mandibular closing muscles to facial skeletal type. Any orthodontic patient will attest to the fact that their ability to masticate is altered by their orthodontic treatment. No experiments have been conducted to measure the change that is clinically obvious in the patient's ability to exert masticatory force on his dentition, as previous studies were performed prior to any orthodontic treatment that may have been required. The purpose of the present study is to evaluate the ability of orthodontic patients to exert maximum biting pressure and to detect any possible alterations in bit~ force that may occur afte~ the initiation of orthodontic treatment. -2- ·REVIEW OF THE LITERATURE 1. Measurement of the force generated by 'the closing muscles of mastication. Measurement of biting force was first reported in the literature of Borielli of Jtaly in 1681, but it was not until the late nineteenth century that.any concerted effort was made to accurately determine the amount of force available to the human masticatory apparatus. The inst~ument called a'gnathodynometer was first constructed by Patrick and D~nnis (1893) , and was subsequently improved by G. V. Black, This particular·instrument consisted of a small bite plate, a compressible spring with pointer, and a graduated scale. G. V. Black (1895) utilized the gnathodynometer, as described above, to analyze the biting force of 50 patients, most of whom were adults over 20 years of age. He found a wide range of force values which were dependent on the age and. physical development of the individuals studied. Black was one of the first to recognize that different values exist for incisors, premolars, and molars. Klaffenbach (1936) stated that "The poundage that the teeth exert on any object or food is individual and -3- consequently cannot be standardized." He further reported, as did Black, that the force exerted by the teeth as recorded by a gnathodynometer is a reflection of the power of resistance of the periodontal membrane, and is not indicative of the entire power of the muscles of masticatiop. Klaffenbach's study determined bite force in the molar region to be an av_erage of 125 pounds, while Black's values averaged 171 pounds. Brawley and Sedwick (1937) gave a comprehensive review of gnathodometery pr.ior to 1937. All the instruments to that date consisted of springs in various relationships to a lever system. Their instrument, similarly designed, was quite bulky and was only suitable for determining force values for entire dental arches. Klatsky~ (1942) measured adult bite forces, and made a distinction between males and females plus right and left sides of the dental arches. His findings on m~les of an average age of 27.19 years with an average of 28.91 teeth were 119.58 pounds on the right side and 112.86 on the left. Females in the same study at 24.91 years of age with an average of 28.81 teeth~provided values of 85.75 pounds on , the right side and 83.91 pounds on the left. The author -4- concluded that unilateral chewers were capable of creating. greater force on the side which performed the greater amount of mastication. Howell and Manly (1948) designed a relatively accurate electronic. gnathodynometer with a narrow bite element suitable for use in all areas of the mouth. They utilized four male subjects ranging in age from 20 to 30 years. Average forces on teeth generated by a closing force on incisors, canines, premolars, and molars ranged from 24 to 198 pounds. Measurement of stress during mastication by use of a strain gauge incorporated into a dental restoration in a molar tooth was accomplished by Anderson (1956). Mean ·maximum loa<Is on three dif fererit types of food· were cal- culated. Measurements reflected only the amount of force ' required to effectively masticate the given food sample, which, however, did not indicate the maximum bite force available. Nyquist and Owall (1968) attempted to measure bite force by use of piezo-electric transducers mounted in rester- ations in molar teeth.' While they found what they considered to be a fairly accurate measurement of vertical masticatory P· .: --5- Pressure, they could not determine the total.force of mastication d~e to the oblique loading of force caused by ~he functional later6trusion of the mandible. 2. Physiological phenomena associated ,with. occlu~_ive force. Pf af fman (19 39) dem.onstrat~d·. that pressure receptors are located.in the periodontal membrane, and that great individual differences existed in response to pressure. He further stated that touch or pressures applied to the intact tooth gave rise to an intense :discharge of impulses in the dental nerves. Force applied in one general direction stimulated the single nerve ending, and pressure rather than tension provided the adequate stimulus for the single ending. Boos (1959) designed a spring-loaded instrument for measuring bite force on prosthetic patients at varying degrees of vertical dimension. ~Although his study was directed toward artifical dentition, an important physic- logical concept was brought forward. He asserted that the ability of a patient to exert maximum occlusal· force varies with change in the vertical dimension. Boos concluded that for a muscle to function most efficently, a normal physiological length from' origin to insertion for that muscle must be attained. p ,;· -6- Storey (1963) in a study on changing vertical dimension stated that there'i~ a position of maximal closing force at an optimal, vertical dimension for every individual. This position was characteristic of the muscle tissue itself. He found that.submaximal closing forces remained the same and in some cases even increased as the optimal vertical dimension was exceeded. These forc.e:s were measured at the increased vertical dime~sions of 1, 2, 5, 10, 12.5, and 17.5 millimeters. Electrom~ographical monitoring of the c~osing muscles of masticatipn was also performed, and a decrease in amplitude was observed as the vertical dimension increased even though the closing force remained the same. These concepts were related to the natural dentition by Atkinson and Shepard (1967). They concluded that during normal mastication, forces increase rapidly as the teeth approached maximal contact position in a healthy dentition.