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Signs of Occlusal Instability

By Dr. Shannon Johnson

Good Vibrations?

As clinicians, the very purpose of our dental exam is to thoroughly evaluate each patient for any sign of instability that will lead to breakdown of the masticatory system.  Not including macro-trauma, there are only two simple reasons for the system to break down:

1.  Microorganisms (bacteria, viral, fungal)

2.  Stress from microtrauma

tooth vibration

Dental school trained us exceptionally well in treating the microorganism component—caries and periodontal disease. Stress from microtrauma results in what we see clinically as occlusal disease or occlusal instability, an entity that can be more challenging to manage.  Fremitus is a more subtle, but nevertheless important sign of occlusal instability that will be the focus of this discussion.  The presence of fremitus is indicative that the patient’s occlusion is not stable!    

  • Fremitus: a vibration perceptible on palpation; in dentistry, a vibration palpable when the teeth come into contact.

Checking for fremitus of each tooth is an absolute necessity if we are to consider our exam complete.  It is a clinical sign that is often overlooked during both the examination and the restorative process. The main sources of fremitus are:

  1. A deflective posterior incline contacts that drives the mandible forward

  2. An envelope of function that has been restricted in some way…think iatrogenic

  3. Failure to provide for long centric on anterior teeth—postural freedom from centric relation. 

Signs Instability web resized 600

Identifying fremitus only requires placing the fingernail/tip of our index finger lightly on the facial surfaces of the teeth and asking patient to “tap-tap,” gently and firmly, then grind around.  If you feel ANY movement or vibration…fremitus is present.  It is important to check for fremitus both with the patient reclined and with the patient sitting up.  Fremitus = occlusal trauma = occlusal instability.

  • Occlusal trauma is defined as trauma to the periodontium from functional or parafunctional forces causing damage to the attachment apparatus of the periodontium by exceeding its adaptive and reparative capacities.  

Discovering fremitus requires further investigation, not a “wait and see” approach.  Without treatment, fremitus can progress to hypermobility, excessive wear, and/or shifting of anterior teeth.  Note: if fremitus is present with active inflammation, the periodontium must be treated as well as occlusal adjustments alone will not solve this problem.

Obtain accurate and complete records in order to systematically treatment plan the best option for stabilizing the occlusion.  During and after treatment, when evaluating the success in stabilizing the occlusion, remember that a negative fremitus test is an absolute must.  So in this case, there are no good vibrations!  

dental occlusion stability whitepaper

Dr. Johnson grew up in a small coal-mining town in Kentucky. She excelled academically and eventually earned her doctorate from the University of Louisville School of Dentistry. Today, she is one of only a few dentists to be appointed as an Academic Advisor for the prestigious Dawson Center for the Advancement of Dentistry where she assists in training other dentists regarding new clinical techniques and advances. Dr. Johnson and her husband, Jason Johnson (an IT professional), have been married five years and have a beautiful daughter.