The Concept of the Complete Examination
Five diagnostic components for predictable restorative success
Proper and complete clinical evaluations are the basis of proper and complete diagnoses, which in turn lead to relevant and predictable treatments. Patients require restorative dentistry for reasons such as decay, tooth breakage or weakening, wear, or complete tooth loss. It is very predictable to diagnose and treat issues related to bacteria; there, cause and effect are clear, and both the patient and the doctor are often comfortable with such a scenario.
The most common yet under-diagnosed dental condition today is excessive tooth wear. While patients often seek cosmetic rehabilitation due to excessive chipping and wear of both posterior and anterior teeth, many cases are treated without a clear understanding or diagnosis of what caused such severe loss of tooth structure. This is unfortunate, because if the cause of the wear to the natural dentition is not remedied during treatment, the restored teeth will likely suffer the same prognosis.
Examining the System
It is important to understand that the teeth are functioning within a system. This system is composed of the temporomandibular joint (TMJ), the muscles of mastication, the posterior teeth, the anterior teeth, and their connection to the central nervous system. These components, which comprise the stomatognathic system, must function in harmony for the patient to have comfort and long-term stability. A lack of harmony will show up as signs and symptoms in one or more components of the system. These could include wear, migration, and mobility of the teeth; soreness in the muscles of mastication; and pain, tension, clicking and popping, and crepitus in the TMJ.
To address these symptoms, the restorative dentist must have a system by which to evaluate and examine the components of the stomatognathic system. The dentist must also possess the training to interpret this data and formulate a complete diagnosis. This will lead to a treatment plan to address any instability in the system.
The following components of the complete examination are discussed in detail below:
1. Palpation of the muscles of mastication.
2. Evaluation of the range of motion of the mandible.
3. Evaluation of the dentition for sign of instability.
4. Evaluation of the occlusion and requirements of occlusal stability.
5. Determination of the restorability of the TMJ.
Palpation of the Muscles of Mastication
The muscles of mastication should be free of inflammation and capable of palpation without discomfort. The dentist must identify soreness to palpation in the superficial masseter, deep masseter, anterior temporalis, posterior temporalis, and the medial pterygoid. Patients should be asked about muscular discomfort. If they are experiencing any aching in the muscles, they should describe its intensity, duration, and frequency, as well as whether there is any cramping or knotting. The doctor should examine the masticatory muscles for signs of hypertrophy. Most patients have never had their masticatory muscles examined and are often unaware of the level of muscle knotting and soreness that is commonly present. Patients with headaches are also often unaware of possible occluso-muscular causes and implications. Many people have adjusted to a "baseline" of muscle discomfort and may be unaware of what it feels like to be muscularly comfortable.
Evaluation of the Range of Motion of the Mandible
Much information can be obtained by observing the range of motion of the mandible. The dentist should be aware of the effects of muscle hyper-contraction and intracapsular joint derangement. The mandible should rotate (condyles in the glenoid fossa) approximately 20 to 25 mm. Opening larger requires translation of the condyle to a maximum normal opening of 40 to 60 mm. The mandible should be capable of protruding more than 8 mm and moving laterally left or right at least 8 mm.1 These measurements can be made using a range-of-motion ruler (Figure 1 and Figure 2).
Movement to maximum limits should be asymptomatic, smooth, unrestricted, and symmetrical. Deviations and restrictions should warrant further investigation to determine a muscular or intracapsular origin.
Evaluation of the Dentition for Signs of Instability
The signs of instability in the dentition would include abnormal wear, tooth movement that is not wanted, broken teeth, and teeth with excessive mobility (Figure 3 and Figure 4). A normal amount of tooth wear occurs slowly, following a minimally progressive course. In an adult, tooth wear averages 10.7 µm per year. Exposed dentin is not normal and should be evaluated to determine its cause. Because dentin wears at a rate far greater than enamel, this can cause wear and breakdown to accelerate.2
Tooth movement that is unwanted is the result of excessive force on a tooth or breakdown of its supporting structures. Normal teeth have 50 to 100 µm of mobility that varies by time of day and amount of force applied. Numerous factors can lead to increased tooth mobility. Periodontal disease is a common cause of mobility; however, excessive load and lateral forces found in occlusal trauma can also cause this condition to exist.3 Thankfully, the mobility can be resolved to pre-trauma levels once the cause is removed.4 Patients can exhibit varying degrees of some or all the signs of instability.