Have you been frustrated with your bite? Doctors tell you that your bite is off and begin to adjust your bite to some position while you are laying in their dental chair with your mouth open and they are spot adjusting various positions. You are instructed to tap your teeth together on blue paper and the dentist continues to grind various spots with his high speed drill. The goal is to make your bite even. Tap tap…grind grind…your bite seems to come together evenly…. After a few minutes the dentist has completed the equilibration process and you sit up in the dental chair and immediately notice that your front teeth are touch slightly more, but you slide your jaw back to make all the back teeth come together. You naturally assume it will be just fine. After many return adjustment visits you and the dentist become frustrated….you point with your finger trying to show the doctor where your bite is hitting wrongly…he looks, but he can’t see anything wrong….all the blue marks seem to appear evenly to the dentist, but you know something doesn’t feel quite right….Hmmm?
A Light Weight Sensor Array (Jaw Tracker) is used to visualize mandibular movements with the computerized K7 (Myotronics Kineseographic Evaluation System, Kent, WA). The Myomonitor J5 TENS is used to relax muscles and assists in overcoming proprioceptive occlusal engrams.
Dentists today use computerized technology to measure jaw positions relative to ones habitual bite position (home base or centric occlusion – CO). Computerized mandibular scanning (CMS) technology measures 3 dimensional movements of the mandible as it travels from rest to habitual centric after low frequency TENS pulse stimulation. The technology tracks mandibular movements via a small tiny magnet that is placed on the front of the lower teeth along with a jaw tracking device called a Sensor Array. The sensor array is light weight (4-6 oz.) and is placed on the head and held with a velcro strap. The mandible is free to move naturally and the sensor array (K7 jaw tracker) is able to record any and all jaw movements on to a laptop computer while the patient is in an upright sitting position.
Observable Features:
- Allows the clinician to visualize the mandibular position in space (sagittal and frontal) as it is referenced to habitual occlusion (habitual trajectory).
- Allows the clinician to visualize an optimal physiologic position after TENS (Myo-trajectory or neuromuscular trajectory, typically anterior to the habitual trajectory).
- Used after muscle relaxation (TENS to contrast habitual movements as it relates to physiologic rest and the myo-trajectory movements.
- Allows the clinician to distinguish whether true physiologic rest has been achieved prior to bite registration.
- Allows the clinician to more accurately and physiologically determine a starting postion for the mandible without manual manipulation. The dentist can verbally instruct the patient to close to within 0.1-0.3 mm of accuracy to a targeted position determined by the doctor and physiologic data seen on the computer monitor.
- Assists the clinician to determine whether equilibration is required or not along the sagittal, frontal and vertical planes.
Determining A Reference Position for Diagnosis and Treatment
A seated condylar reference is not the goal of Physiologic Occlusal treatment, but rather a physiologic reference point is required for all disciplines of occlusal dentistry involving restorative/prosthetic, orthodontic/0rthopedic and or TMD diagnosis and treatment.
The Myo-Trajectory (Antero-Posterior (AP) path of jaw closure) and the quality of a synchronized repeatable terminal contact position as referenced is used and objectively measured to achieve precision in treatment for occlusal dentistry. One of key reasons for using scientific technology is to assist the clinician in objectively determine whether an occlusion is closing on a habitual trajectory (accommodated jaw closing path) or does it close on a more anterior myo-trajectory.
This perspective further refines classic gnathological thinking combined with neuromuscular.
Jaw Shifts Can Be Measured
Many clinicians as well as patients have often been bewildered by jaw shifts that often occur after occlusal treatments were rendered (e.g., equilibration, occlusal adjustments, fillings, crowns, full arch reconstruction, occlusal appliance splint therapy). It is this change in occlusal/bite relationships that have been noted for decades amongst dentist when working with their patients that have caused the dentists to begin a further investigation to objectively use computerized instrumentation to measure and quantify these jaw changes. Once the dentist is able to measure the habitual jaw closing paths relative to a habitual centric occlusion (CO) along the antero-posterior paths of closure and compare any changes in jaw position after muscle relaxation using low frequency TENS to identify a more physiologic jaw closing path (myo-trajectory, also called a neuromuscular trajectory).
Understanding the Bite (Using Scan 4/5 – A Key Diagnostic Tracing of the K7 Evaluation System)
The final computerized CLINICAL EXPRESSION of the relationship between, TEETH, MUSCLES AND JOINTS
A comprehensive understanding of Scan 4/5 is BASIC to understanding NEUROMUSCULAR OCCLUSAL PRINCIPLES. Scan 4/5 is a computerized CLINICAL EXPRESSION of the RELATIONSHIP OF TEETH, MUSCLES AND JOINTS.
The left side of the screen (Scan 4) is recorded AFTER the patient has been pulsed with the low frequency TENS for at least 45 minutes. If the muscles have been truly relaxed, the jaw will be at its neuromuscular rest position (blue records the vertical position of the jaw over time. This position is usually a different “rest position” than a habitual (accommodated ) relaxed jaw position because the tension-shortened muscles have lengthened as they became relaxed during the 45-60 minutes of TENsing. Notice that, as the muscles relax and lengthen, the intra oral freeway space between the teeth usually increases. The red line measures over time the antero-posterior (AP) mandibular position. the green line measures over time the frontal mandibular position.
The right side of the screen displays scan 5 represents a summation of the jaw movements and positioning over time seen from the sagittal and frontal views. The lower colored bars display simultaneous electromyographic (EMG) muscle recordings of the temporalis, masseter, cervical and digastric/suprahyoid musculature.
Visualizing this data allows the dentist to observe small jaw changes within 0.1 millimeters.
- It allows for effective monitoring of the Myomonitor/TENS pulse both sagittally and frontally.
- Monitors muscle activity – whether high or low EMGs
- Clinician can see where to set the Myo-centric Target when recording a bite registration.
- Clinician can see how much tooth will need to be ground prior to equilibration treatment.
Using this technology allows any trained dentist to determine prior to any equilibration procedure whether to equilibrate or not to equilibrate the patient’s teeth.
The pink triangle shows the dentist the calculated amount of tooth structure that would have to be ground or adjusted away to allow the mandible to close without strain along the myo-trajectory to accommodate a new centric occlusion.
Rules of Equilibration – When to Grind and When Not to Grind (That is the question?)
- Over 0.2 square mm usually indicates a need for an Orthosis (additional vertical height is required to build up or add up over the occlusal surface in the posterior regions). Equilibration is not recommended, because grind over 0.2 sq. mm of tooth usually begins to destroy healthy tooth structure and usually contributes to a further loss of vertical dimension of the jaw and effecting normal muscle function.
- 0.2 square mm or less – Equilibration or coronoplasty may be considered to accommodate the Ap descrepancy shift in the bite without destroying tooth structure and or losing vertical dimension of the jaw.
Note: 1.7 square mm of tooth structure would have to be ground on the sagittal plane to accommodate jaw closure along the neuromuscular path of jaw closure.
This measured and objective approach to dentistry clearly and unequivically protrays a level of clinical advancement that the neuromuscular trained clinicians are able to apply with their patients. These advanced techniques clears up any question as to what occlusal philosophy and approach is appropriate and conservative.
To read more on: Scientific Studies Supporting – Neuromuscular Instrumentation
To read more on: Neuromuscular Instrumentation – ADA/FDA Approved
