Artificial Neural Network Learns to Differentiate Normal TMJs and Nonreducing Displaced Disks after Training on Incisor-Point Chewing Movements

ABSTRACT

Previous authors have described four frontal gum-chewing patterns associated with normal and abnormal TMJ disk-condyle relationships. The objective of this study was to create an automatic detection capability (expert system) by training an artificial neural network to recognize nonreducing displaced disks from frontal chewing data. Sixty-eight (68) subjects, 29 with normal joints, 18 with unilateral nonreducing displaced disks and 21 with bilateral nonreducing displaced disks were selected from a continuous series of patients seeking treatment for TMD. Right-sided gum chewing was recorded from all patients. Left-sided chewing was also recorded from the right unilateral patients. 50% of the vertical, lateral and timing values at 10%, 65% and 100% of opening and at 30%, 70% and 90% of closing were used to train an artificial neural network. The remaining 50% were used for testing. All normal subjects were detected as normal (specificity = 100%). Two bilateral and two unilateral patients were not detected (sensitivity = 91.8%). Four (4) patients received the wrong classification (unilateral vs. bilateral) and one patient received both (undecided) for an overall accuracy = 86.8%. The artificial neural network detected, at an acceptable level of error, the presence and type of nonreducing disk displacement from frontal plane jaw recordings of gum chewing in a group of real patients seeking treatment for TMD. Since it is very inexpensive to conduct, mastication analysis appears to have the potential of an excellent cost/benefit ratio.

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Notes on contributors

John C. Radke

Mr. John C. Radke received his M.B.A. from The Keller Graduate School of Management (Chicago, Illinois) in 1992. He is currently president of BioResearch Associates, Inc., Milwaukee, Wisconsin. Mr. Radke has published numerous articles and has lectured internationally on the scientific methods (Fourier series, wavelet transforms, artificial neural networks, and genetic algorithms) that are used for the analysis of temporomandibular joint vibrations, electromyographic data, and functional and parafunctional jaw movements. During his thirty year career in dental research and new product development, he has received many patents for his innovative instrument designs. He is a member of the International Association for Dental Research, the International Neural Network Society, the American Association for the Advancement of Science, and an honorary member of the Italian Academy of Electromyography and Kinesiology.

Robert Ketcham

Dr. Robert S. Kull received his D.D.S. degree from Temple University in 1970 and completed a General Practice Residency at the Erie County Medical Center in 1971. From 1974 to 1985, he was Assistant Clinical Professor SUNY at Buffalo School of Dental Medicine teaching clinical restorative dentistry. He received his Master of Science degree in Oral Sciences with a concentration in TMD and neuromuscular physiology from the State University of New York, Buffalo in 1988. While maintaining a private practice for the past 30+ years, Dr. Kull has also been affiliated with four major hospitals in the greater Buffalo area. He has previously coauthored numerous articles and given lectures both nationally and internationally. He is board certified by the American Academy of Pain Management and has been awarded fellowships by the Academy of General Dentistry and the International College of Craniomandibular Orthopedics. He is also a member of the American Academy of Craniofacial Pain, the International Association for Dental Research and the American Dental Association.

Barry Glassman

Dr. Barry Glassman received his D.M.D. degree from the University of Pittsburgh School of Dental Medicine in 1973. He served as a captain in the U.S. Army Dental Corps from 1973 through 1975. He has maintained a private practice for the past 28 years and is currently affiliated with three major hospitals in the greater Allentown, Pennsylvania area. He lectures extensively, both nationally and internationally, on temporomandibular joint dysfunction (TMD) and sleep disorders, and the clinical relevance of physiologic findings to dental diagnosis and treatment. Dr. Glassman is board certified by the Academy of Dental Sleep Medicine, is a Diplomate of the American Academy of Pain Management, and has been awarded fellowships by the American Academy of Craniofacial Pain and the International College of Craniomandibular Orthopedics.