By Chris Stevens, D.D.S.
Getting started in neuromuscular occlusion is easier (and less expensive) than you might think.
There are many factors to consider when investigating and adopting an occlusal philosophy. Is it valid? Will it work in my hands for my patients? Will I know if I am doing it the right way? What is my startup cost?
Since a complete neuromuscular philosophy employs computer-enhanced technology, startup costs are a significant factor for most clinicians, but the path may be easier and cost less than you think.
There are three distinct, but related, components to consider when you initiate occlusal treatment using the “bare essentials.” These include imaging the TM joint, positioning the maxillary arch, and positioning the mandibular arch relative to the maxillary arch.
TM Joint Imaging
TM joint imaging has traditionally been done primarily for patients suffering from cranio-facial pain. But the need for joint imaging has changed over the years. Today it is not just for cranio-facial pain patients. Clinicians worldwide are recognizing the need to find out if the TM joint is healthy before initiating comprehensive dentistry.
Joint imaging for comprehensive care patients needs to be accurate, accessible, and cost effective. There are three conventional means of joint imaging: radiographic, magnetic resonance, and sound.
High quality radiographs done in the office may require a sizable capital investment. These radiographs may be obtained from radiographic laboratories generally only in more urban areas. Magnetic resonance images of the TM joint, although accurate, also can be both difficult to acquire and costly to the patient.
A tool available to dental clinicians over the past two decades continues to demonstrate accuracy and availability while being cost effective for both the clinician and patient. Joint Vibration Analysis (JVA) (BioResearch, Inc., Milwaukee, WI) records vibration, or sound, emanating from the TM joints. Computerized recording and subsequent analysis of joint vibrations is very effective for evaluating the current status of the patient’s TM joints, especially compared with clinical evaluation with palpation and/or stethoscopic examination or patient reporting.(1-3)
JVA is acquired by placing a recording headset over the joints. The patient is asked to open and close so that vibrations occurring during movement within the joint can be recorded and stored by the computer for subsequent analysis. JVA has a specificity (ability to identify normal when normal exits) of 95 percent(4) and sensitivity (the ability to identify disease when disease exists) up to 100 percent.(5)
Since JVA is done in the office and takes less than five minutes to record, accessibility is also not an issue. The cost of JVA equipment is about $8,200 so recouping the up front cost can be done rather quickly.
Some have suggested that using JVA to diagnose the patient’s joint health prior to onset of care can help the clinician ensure a result that is favorable and predictable. For me that means helping to establish the patient’s readiness to accept and tolerate my care without becoming symptomatic.
Positioning the Maxillary Arch
In my practice, there are two primary considerations with regard to the maxillary arch: occlusal plane and position of that plane in space. For assistance in occlusal plane determination I employ the Accu-Liner (Accu-Liner Products, Woodinville, WA) articulator system.
Occlusal plane position is established by using the hamular notch – incisive papilla plane. This plane was discovered to be an accurate representation of level by Dr. Harry Cooperman who studied 10,000 skulls over a five-year period.(6) A level maxillary plane assists both in creating a level smile and dispersing occlusal forces.
An accurate impression is obtained that records both hard and soft tissues including the hamular notches. The Accu-Liner utilizes a pin and fence system to orient the maxillary cast to a level stage. From that mounting, diagnostic and treatment decisions can be made in accordance with a level plane.
Vertical position of the plane in space is established through f-point incisal edge positioning. The patient is asked to perform a series of phonetic sounds containing f and v.
Establishment of the maxillary plane position is based on the length of the central incisors required to touch the lower lip wet-dry line while performing f and v phonetics. This length is reported to the lab so the position of the maxillary plane can be utilized in both the wax-up stage and the final restorations. The cost of the Accu-Liner articulator system is approximately $1,800.
Positioning the Mandibular Arch
Establishing neuromuscular occlusion means utilizing muscular input to determine the physiologic rest position of the mandible. It is from this rest position that isotonic elevation of the mandible through freeway to the proper maxillary plane occurs. I employ transcutaneous electrical neural stimulation (TENS) (BioResearch, Milwaukee WI) to establish this muscular trajectory.
TENS is an ultra-low frequency neural stimulator that emits low level current to the 5th and 7th cranial nerves. This intermittent current relaxes the muscles innervated by the nerves and creates a trajectory of closure for the mandible.(7)
The superior end point of this trajectory is recorded in bite registration material. This mandibular position becomes the new centric occlusion and is transferred to the Accu-Liner system. The Accu-Liner articulator system. The Accu-Liner utilizes a pin and fence system to orient the maxillary cast to a level stage. There are two primary considerations with regard to the maxillary arch: occlusal plane and position of that plane in space. Establishing neurouscular occlusion means utilizing muscular input to determine the physiologic rest position of the mandible. With the cost of TENS being about $800, the total cost of the bare essentials is less than $10,900 or about one veneer case. And with this investment you are well on your way down the path toward neuromuscular occlusion.
Chris Stevens received his D.D.S. from Marquette University. He has shared his knowledge on PC-enhanced diagnostics, patient evaluation, and stabilization worldwide. He is an expert in neuromuscular bite registration and physiological mandibular positioning. Dr. Stevens maintains a private restorative/TMD practice in Sun Prairie, Wisconsin.
- Dworkin, S.F., LeResche, L., and Derouen, T. “Subject Reliability of Clinical Measurement and Temporomandibular Disorders,” Clin. J. of Pain, 1988.
- Eriksson, L., Westesson, P-L., Sjoberg, H. “Observer Performance in Describing Temporomandibular Joint Sounds.” J Craniomandib Prac, 1987, 5:32-35.
- Hardison, D.J., Okeson, J.P. “Comparison of Three Clinical Techniques for Evaluating Joint Sounds.” J Craniomandib Prac, October, 1990, Vol. A, No. 4.
- Bessette, R.W. “A Clinical Study of Temporomandibular Joint Vibrations in TMJ Dysfunction Studies.” Presentation – American Academy of Head, Neck Facial Pain, and TMJ Orthopedics. Kansas City, MO. August 15, 1992.
- Ishigaki, S., Bessette, R.W., Maruyama, T. Vibration. “Analysis of the Temporomandibular Joints with Degenerative Joint Disease.” J Craniomandib Prac, 1993, Vol. 11, No. 4, 276-283.
- Cooperman, H.N., Willard S.B. Studies of the Louchheim Collection of Skulls. New York: American Museum of Natural History, 1960.
- Allgood, JP. “Transcutaneous electrical neural stimulation (TENS) in dental practice.” Compend Contin Educ Dent.October, 1986, 7(9):640, 642-4.