The basic occlusal exam
An occlusal exam is something that we should all be doing, but there seems to be significant confusion between what we may have been taught as undergraduates and what seems to be applicable in practice.
For the majority of practitioners who have no interest whatsoever in managing occlusal problems there is still a need to be able to assess and carry out a simple occlusal exam that:
1. Is in keeping with their professional responsibility
2. Allows them the confidence of knowing when they can carry out restorative treatment without fear of inadvertently initiating problems
3. Quickly elucidates the ‘problem’ patient for appropriate referral.
What questions would we like our occlusal examination to answer?
1. Can I use the patient’s existing occlusion?
2. Do I need to change the occlusion?
3. Am I at risk of initiating an occlusal problem?
4. How do I know if there is a joint problem that I should do something about?
5. Is this patient a bruxist who will break all my restorations?
In effect, the real question that the examination needs to answer is: Is this occlusion physiologically stable or pathological?
A physiologically stable occlusion allows for confident progression to restorative dentistry. A pathological occlusion on the other hand will require more in-depth analysis and planning and is where much of the confusion within occlusal concepts and theories lies.
This brief article describes how to easily confirm a physiologically stable occlusion. A basic occlusal exam for restorative dentistry should address four areas:
1. Extra-oral assessment
2. Intra-oral assessment
3. Load testing of the joints
4. First contact and slide from centric relation to position of maximum intercuspation.
The extra-oral assessment is primarily looking at the muscles of mastication and their effect.
- Does the patient suffer from headaches? If yes, ask about frequency, duration, location (there is a strong correlation between tension headaches and parafunction, especially if the patient reports waking regularly with headaches).
- Palpation of the muscles of mastication (as a minimum the ‘trigger points’ of masseter and temporalis).
- Range of movement assessment – ask the patient to perform maximum unforced opening and left and right eccentrics. Look out for any significant limitations or deviation (Fig 1).
No headaches, no muscle pain and no limitations to the range of mandibular movements, suggests a physiological occlusion suitable for restoration.
Is there any pathological wear? Remember that teeth do wear physiologically and that this can be diet dependant. Your older patients are going to exhibit greater wear than the younger ones.
If there is wear, where is it? Molars, palatal surface of incisors or incisal edges? If there is significant wear but not where you are planning restorations, then you may not need to worry. Is there any tooth mobility which is unexplained by periodontal pathology? Is there fremitus? Ask the patient to close together and, while holding together, rub the teeth from side to side – do any teeth move? (Fig 2)
Are there any cusps missing? Is there a history of tooth fracture? Why were missing teeth removed? What condition are the existing restorations in occlusally?
No evidence of excessive wear, mobility or fracture suggests a physiological occlusion suitable for restoration.
Load testing of the joint
In order to load test the joint, it is necessary to find centric relation. This is the point at which a lot of the confusion can start as there are many different definitions, or descriptions, of where it is.
It is important to realise that centric relation is a conceptual position, which relates to the position of the mandible to the maxillae. It really does not matter how you wish to describe it; all that is important is that everyone is talking about the same position (give or take a few microns).
For arguments sake, we will describe centric relation as the axis of rotation when the condyles are fully seated, in healthy joints.
It has absolutely nothing to do with the teeth or the muscles and, crucially, is inter and intra-operator repeatable.
There are different ways to achieve centric relation, either through manipulation or using an anterior deprogrammer such as a leaf gauge. Neither way can be learned from books articles or presentations, these are learned skills and need hands-on tuition for the operator to be confident in achieving them (Fig 3 and 4).
Once the patient is in centric relation, either the masseters are contracted by the patient or the condyles are forceably loaded. If this action causes pain, then joint instability should be considered (Fig 5).
No evidence of pain on loading suggests a physiological occlusion suitable for restoration.
First contact and slide from centric relation to position of maximum intercuspation
Once again, in centric relation, the mandible is hinged towards the maxillae until a tooth contacts. This is the first point of contact and it should be noted. The patient is then asked to squeeze the teeth together and the ‘slide’ noted. Anything more than a 0.5mm should be noted.
The significance of the slide from first contact is that the first contact is responsible for programming the muscles of mastication. Put another way; the existence of the first contact causes the muscles of mastication to move the mandible in such a way as to miss this first contact and achieve maximum intercuspation.
If you are planning to restore the tooth which has the first contact, and in so doing remove it, there is a real possibility that the muscles will reprogramme (proprioception changes). Immediate results of this could be:
- loss of the restorative space you just created
- a crown or filling that the patient feels is high and needs multiple adjustments for
- general discomfort with the bite
- inducement of parafunctional activity.
A slide of less than 0.5mm from first contact to maximum intercuspation, or first contact and slide on teeth that you are not planning to restore, suggests a physiological occlusion suitable for restoration. If all four areas are assessed, and no potential pathological conditions are found, then the clinician can progress confidently to treatment.
This simple occlusal examination quickly allows the clinician to establish whether an occlusion is physiological or pathological. In being able to carry this out there is a need for the clinician to learn the skills necessary in achieving centric relation and to have the confidence to do so every time.
This article was submitted by Kevin Lochhead, clinical director at Edinburgh Dental Specialists. The concepts and skills discussed are being addressed during a two-day hands-on occlusion course on 22 and 25 November 2011.
For further information on the course, e-mail
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