THE GNATHOLOGICAL APPROACH versus THE NEUROMUSCULAR APPROACH

THE GNATHOLOGICAL APPROACH versus THE NEUROMUSCULAR APPROACH to Dental Diagnosis and Treatment
by Clayton A. Chan, D.D.S.

An Editorial:

There are two rivaling philosophies of treatment in this country today by which clinical dentist are treating their patients.

The first and oldest philosophy is that of Gnathology which is based on a belief that the temporomandibular joints hinge on an axis of rotation in the glenoid fossa of the skull. All occlusion is guided and brought together to a finally tuned order, determined by the axis of jaw joint rotation. The emphasis is on occlusion and joint position which is fundamentally called “centric relation”.

The second newer philosophy is Neuromuscular, based on the understanding that the temporomandibular joints are in a physiologic resting position based on the guidance of muscles and stabilized by the occlusion of both the upper and lower teeth. Emphasis is on a physiologic position of the jaw/ mandible position to the skull (neuromuscular rest position), the physiology of rested muscles to support a physiologic occlusion for stability of all three entities: the TM joints, the muscle and the teeth.

The Great Debate
Both these philosophies are strongly debated among treating clinicians that have been seeking the answers to the mysteries of occlusion (the manner in which teeth fit together) with all it’s challenges that include the treatment and management of the mandible, the muscles of mastication, the supporting hard and soft tissue structures of the temporomandibular joints, the physical as well as the emotional factors that effect their patients. Jaw joint position has been a major contention among the various schools of thought, with strong opinionated feelings to support each ones view, clinical experience and teachings they have received.

A Battle to Success
It has been a battle as well as a struggle to reach this present day success of acknowledgement. Due to the natural obstacles that any newly developed innovation encounters, the neuromuscular principles that are presented are often misunderstood and are mercilessly and often illogically criticized by those who would not nor could not renounce their obsolete convictions regarding traditional thinking about the physiology of the masticatory complex involving the mandible, skull, musculature, temporomandibular joints and teeth.

What is Gnathology?
The term “Gnathology” was first coined by Dr. Harvey Stallard, of San Diego, California. This term stems from the Greek word gnathic or gnathos in origin referring to the jaw.

Gnathology refers, in its broad and all-inclusive sense to the gnathic system – the system of measuring jaw relations and functions. Dentistry is a branch of medicine and deals with the teeth and supporting tissues whereas gnathology is a specialty of dentistry that concentrates on the entire gnathic system and the whole patient.

Dr. Harvey Stallard a dentist and a founding father of the gnathological concept stated, “Gnathology includes the exact relations existing between the teeth and the morphological border movements of the condyles: the lateral, the anterior and the rearmost positions… and most importantly, gnathology includes knowing how the nine various directions the condyles move laterally and medially in vertical chewing movements. How the chewing cycle of cusp points may be related to centrically related cusp-fossa occlusion, is wanted gnathological knowledge.”

I myself for years emphasized that gnathological treatment endeavors to relate the teeth properly to each other in such a way that they will have a cooperative relation to the jaw motions and joints. I later realized through clinical practice that even though the concept and philosophy sounded well and good, it fell short of physiologic science and objective ideals purported when treating my patients daily in clinical practice, especially in those more challenging cases.

Outdated Dental Concepts
Gnathological principles originated in the 1930’s by some very innovated doctors who had the desire to understand mandibular/ jaw movement by means of mechanical instrumentation called (articulators). These mechanical devices were designed based on notions and opinions of persistent doctors who believed the jaw joints functioned in a certain particular hinging-rotating manner, thus influencing their understanding of dental occlusion, mandibular movement and jaw function. Since these misleading concepts have continued to persist through time to the present day, these notions are still pervading the present day dental curriculum handed down from the early inventors to today’s learning dental student.

Science and Technology
Science and technology in the dental field has greatly advanced to a higher level of understanding of the masticatory system and accompanying structures through the work of Dr. Bernard Jankelson and continues to this day by his son Dr. Robert Jankelson. It is based on scientific instrumentation that objective quantifiable data can be recorded to access mandibular movements in function and at rest. Numerous scientific study have been published in scientific and referred journals nationally and internationally to bring to light the dynamics of mandibular function, muscle activity during resting modes and active modes. Mandibular paths of motion can accurately be recorded in six dimensions (vertical, anterior/ posterior, frontal/ lateral, pitch, yah and roll) to determine pathologic activity from physiologic. These recordings and acquired data can effectively confirm the patients feelings and concerns due to this innovate technology. An optimal physiologic mandibular position can now be understood without biased and opinionated views for each individual patient, thus giving rise to accuracy in treatment and predictable success. Clear reliable evidence can now be gathered and studied to understand the true pathophysiology of mandibular movement, muscle activity, its function and its relation to occlusion/ teeth and the temporomandibular joints for each individual patient needing treatment.

Clearing Up Historical Confusion
Today these innovative diagnostic aids (computerized electro-diagnostic instrumentation) can clearly help clarify the misunderstandings, the false and misleading theories that have plagued and clouded the understanding of the majority of today’s dentists, dental schools, institutions and those in the health profession. No longer do we need to contend with treatment opinions and subjective experiential guesses to treat our patients. All doubt and question can be laid aside if those that are treating patients in need are willing and bold to lay aside old fashion concepts and face the truth of scientific evidence and objectivity.

A Neuromuscular Approach to Dentistry
Dr. Maurizio Bergamini, M.D. stated so clearly, “The field of neuromuscular dentistry has matured to adulthood. Over twenty years of study and research confirmed by clinical and experimental controls have enabled this special discipline to assume a respected role within the medical sciences. At last, it has achieved wide acceptance, is taught in the universities of several countries, is discussed at medical meetings and congress, and is considered an indispensable clinical method for an increased number of clinicians.”

Neuromuscular dentistry has been able to assert itself, with the thanks to Bernard Jankelson’s keen intuition about the fundamental role played by the neuromuscular system involving all the components of the human anatomy of the head, neck, face, and the mouth with all its dysfunctions. He had the ability to measure and control the biophysical and biochemical phenomenon which determined jaw movements. Dr. Jankelson’s brilliant motto sums up the neuromuscular approach so well: “If it has been measured, it is a fact; if it has not been measured, it is an opinion.”

– from the textbook titled: “Neuromuscular Dental Diagnosis and Treatment” by Robert R. Jankelson, 1990.

Neuromuscular Dentistry Answers Questions that Gnathology Cannot
The neuromuscular approach although rarely talked about or discussed in common lectures and teaching institutions today, is certainly welcomed in this age of dentistry among those that have been seeking the truth to understanding the complexities of dental care and treatment, especially in the realm of restorative dentistry and musculoskeletal/ TMJ/ myofacial pain problems. For many of us that have been the recipients of the out moded teachings of gnathologics and seeing the short comings of the standard dental teachings in clinical practice, it is refreshing and inspiring to understand how the stomatognathic systems truly functions in light of supporting scientific instrumentation that can record and verify the observations and symptoms presented by our patients in everyday clinical practice.

It is Scientific and Physiologic
The Neuromuscular Approach is scientifically and physiologically based. There are many health and medical disciplines that support and confirm this view both clinically and physiologically. Other professionals that support and understand this approach to dental care and treatment are osteopathic physicians, certain physicians that are involved with head and neck pain management, chiropractors, cranio sacral message therapist, physical therapist and nutritionist. This diagnostic instrumentation that is discussed in this site is used in many universities and countries internationally to carry out their scientific research and investigative studies.

Many of the questions have been now been clearly answered allowing the neuromuscular dentist to further investigate with openness new doors that he never dreamed could be opened to him in the realm of dental diagnosis and treatment.

Future of Gnathology
Dr. Harvey Stallard stated, “What gnathologist should now make up their minds to do are: First, become proficient by learning the movements of the condyles and the effects of these movements upon cusp heights, cusp shapes, and cusp paths. Second, master the techniques of gathering the necessary data to put into the articulator which will reproduce the necessary jaw relations. Third, acquire an understanding of the anatomy and physiology of the mandibular joints. Fourth, comprehend how the neuro-muscular system assists us to fix the teeth for the best oral automation. Fifth, give greater attention to the nature, structure and health of the periodontium. A gnathologist has arrived when he will be as interested in having glowing health of the gingivae as good form in the occlusion.”

There is certainly still many inroads that need to be made into the present day establishment of dentistry; organized dentistry, dental school curriculum, dental continuing education programs, insurance companies, medical health organizations and programs, as well as current literature. Many of the older established instructors and leaders are hesitatant to make changes in dental curriculum and continuing educational programs realizing the great sacrifice that they will have to make both professionally and personally. Years of established habits and entrenched concepts need to be altered. CHANGE IS ALWAYS DIFFICULT! Careers and reputations are at stake! The system is presently well established. To rock the boat and change the system after many years is always unwanted.

CONCLUSION
As a former gnathologist and still a practicing gnathologist in all its purist sense, I have realized that all true gnathologists when understanding the complete craniomandibular/ neurovasomuscular/ cervical components as well as the occlusal concepts that impact the stomatognathic system is truly striving towards the Neuromuscular Approach. If all the dentists that practice the so called gnathological concepts/ philosophy as taught by doctors Harvey Stallard, B.B. McCollum, Charles Stuart, Peter K. Thomas and all the followers, would perpetuate these teachings to their highest level, they would soon realize that the neuromuscular approach, as confirmed by scientific instrumentation, addresses the missing link of understanding all border movements of the mandible, the determinants of occlusion and the physiology between occlusion (teeth), the supportive and functioning muscles, and the physiologic temporomandibular joint position.

A new and upcoming breed of forward thinking neuromuscular dentists are following in the paths of the innovative Dr. Bernard Jankelson and his son Dr. Robert Jankelson who have been opposed by the establishment for years. Responding to this call of rising to a “higher standard of care” for our patients is our professional obligation to reach this goal. From this neuromuscular perspective any dentist can begin to treat in a complete and comprehensive manner.

Thank you for reading this section.

– These views and opinions presented are by Clayton A. Chan, D.D.S.-

Dr. Chan is a trained gnathologist. He has practiced gnatholgy for many years realizing that gnathologics did not answer nor confront the issues that were being faced with his patients under his care. After persisting to do the best dental care for his patients within the confinements of the standards of that philosophy, he soon realized that there had to be another way that addressed the issues that have been presented in this website. He is pleased that he could share these thought with those that are seeking another side to the story of clinical dental care.

Today he practices a combined GNM approach of both gnathologics and neuromuscular (NM) dentistry with great success and predictability. If the viewer has any questions or concerns regarding what was presented, Dr. Clayton Chan will be pleased to hear from you.

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