141 Examiner standing and patient semireclined
This arrangement is equally comfortable for both the clinician and the patient. It is normally chosen if for any reason the examiner prefers to work standing up or if the patient cannot recline fully because of a general orthopedic problem.
142 Examiner standing and patient fully reclined
This horizontal positioning of the patient with the examiner standing is appropriate only if the clinician is of short stature. Otherwise it would be difficult to stabilize the patient’s head. Furthermore, a dental chair cannot normally be raised high enough for a taller clinician to examine the patient while maintaining an economically sound posture.
143 Examiner sitting and patient fully reclined
The most frequently used arrangement for a tissue-specific examination is with the patient reclined and first adjusts the height of his/her stool so that the thighs are parallel with the floor or are at an angle of approximately 95° from vertical. Finally the height of the dental chair is adjusted. During palpation of the temporomandibular joints the elbows should be bent at a 90Q angle.
Manual Fixation of the Head
In addition to the correct positioning of the patient, optimal stabilization of the patient’s head is an important condition for achieving reproducible results during the examination. Regardless of the patient’s position, it is essential that the head of the patient be supported in all spatial dimensions at all times. A good examination technique requires that forces applied to the mandible in different directions cause no noticeable movements of the head. Not only does optimal stabilization have a positive effect on the patient’s opinion of the examination procedure but it also has solid medical grounds:
• Aggravation of a preexisting problem within the cervical spine must be absolutely avoided.
• Protection of the cervical spine of a patient with diffuse headache or tinnitus is of diagnostic importance. Placing stress on the cervical spine can in some cases precipitate tinnitus. The examiner, however, because he/she is performing a “temporomandibular joint examination” might mistakenly assume that the cause is arthrogenic.
144 Clinician standing and patient semireclined
This combination allows the dynamic tests and the isometric contractions to be carried out quite reliably. However, optimal stabilization of the patient’s head is not always assured for the entire joint-play technique, and the clinician’s back is bent during a large part of the examination. For follow-up exams in which only a few manipulations are to be carried out, however, this position is ideal.
145 Clinician standing and patient fully reclined
Short clinicians who like to stand while working at the dental unit can achieve satisfactory stabilization for almost all examination techniques with this arrangement. If the examination is to take place on a treatment table with adjustable height, the headboard must be shortened to achieve adequate fixation of the head for the various techniques.
146 Clinician sitting and patient fully reclined
The ideal combination for reproducible examination results is a fully reclined patient and a seated examiner. All dynamic tests and isometric contractions can be performed from the 12 o’clock position. All joint-play tests are performed for the right joint from the 1 o’clock position and for the left joint from the 11 o’clock position. During almost all tests the patient’s head is stabilized in all three planes by the headrest, one of the clinician’s hands, and the clinician’s abdomen.
Active Movements and Passive Jaw Opening with Evaluation of the Endfeel
Examination of the extraoral portions of the masticatory system begins with observation of active jaw movements. Active movements do not contribute to the differential diagnosis (Szentpetery 1993), but serve only to document the initial conditions and to verify the symptoms described by the patient. Note is made of the extent of movements in millimeters and any accompanying pain and its location (right/left). None of this in any way supports a differential diagnosis but it does serve to test the conclusiveness of the reported symptoms.
Attention is given to any alteration in the path of movement of the incisal point (deviations and deflections) as has been recommended earlier (Wood 1979), but these are not documented. Because deflection to one side, for example, can have different arthrogenic causes (ipsilateral hypomobility or contralateral hypermobility), it makes more sense to determine the amount of condylar translation. This is done by palpating the lateral poles of the condyles during opening and protruding movements. Under normal conditions a condyle translates almost to the crest of the eminentia.
147 Chart for recording findings from active movements, passive jaw opening, and endfeel
Jaw opening is usually measured between the incisal edges of the incisors (Hesse 1996) and to this is added the overbite (anterior vertical overlap). This is especially meaningful in patients with a “deep bite” (large vertical overlap). The amount of “normal” jaw opening averages 53-58 mm (Ingervall 1970. Agerberg 1974, Wood 1979). Even 6-year-olds have jaw openings of 43-45 mm (Landtwing 1978, Vanderas 1992). Although women in general have more mobile joints (Beighton et al. 1973, Carter and Wilkinson 1964, Hesse 1996), men are able to open their jaws wider by 3-5 mm. According to Agerberg (1974a-d), jaw opening is directly related to body size. It decreases significantly with age and measures only 45-53 mm in 70-year-olds (Agerberg and Österberg 1974, Lysell 1984, Mezitis et al. 1989).
In a selected group of patients with temporomandibular joint problems average jaw openings were 45 mm in men and 39 mm in women (Carlsson and Swardstrom 1971). Contrary to the general clinical impression, a correlation between the extent of active mandibular movement and overall joint mobility is either nonexistent (Westling and Helkimo 1992) or is present only weakly in isolated cases (Dijkstra et al. 1994, Hesse 1996).
While there is little disagreement on the definition of a physiological jaw opening, views vary on what constitutes a limitation of jaw opening: Because only 1.2% of all (not selected) adults have a jaw opening of less than 40 mm(Bit-laretal. 1991), Okeson (1998) accepts this measurement as the boundary, whereas Ingervall (1970) considers a value of 41-42 as a reasonable boundary for limitation of opening. Clinically, however, the many deliberations over establishment of a cut-off value are of no relevance, because a patient may have a measurement of 48 mm, for example, and still be significantly limited because the value was 62 mm before some past event. Regardless of the “scientific boundary” (40-42 mm) a limitation of jaw opening always exists when a patient’s mandibular mobility is objectively found to be less than it was at a previous examination.
There are significantly fewer statements in the literature on the physiological extent of lateral movements. Ingerval (1970) gives average values of 9.8-10.5 mm, Agerberg and Österberg (1974) report 8.7-8.8 mm, and Hesse (1996) reports 10.0-10.5 mm. There is no significant difference between males and females. The ratio of jaw opening distance to lateral movement in a healthy system is approximately 6: 1 (Dijkstra et al. 1998). Lateral movements of less than 8 mm are generally classified as restricted (Ingervall 1970. Okeson 1998).
Protrusive