Temporomandibular dysfunction in pretreatment adolescent patients

E. H. Williamson, D.D.S., M.S.* Augusta, Ga.

T ypical indicators of temporomandibular dysfunction have been enu- merated as follows: clicking in the joint, pain to palpation in the muscles of mastication, and wear facets on the occlusal surfaces of the teeth.l Most of these symptoms have been shown to be associated with malocclusion of the teeth and bruxism. An overlying psychological factor has been shown to be involved in many cases.zl 3 Many persons who exhibit mandibular dysfunction at the age of 20 to 40 have a history of orthodontic treatment near the age of adolescence. When these persons are seen with the overt problem, it is usually by dentists other than orthodontists. Therefore it becomes quite easy to deduce that the orthodontic therapy contributed to the dysfunctional syndrome of these patients. However, the question arises as to whether or not these subjects were symptomatic prior to orthodontic treatment. If they were, it is possible that the orthodontist should be exonerated from total blame. This is not to say that he should not mitigate the chances of future dysfunction occurring with his awareness of the incipient prob- lems and with his subsequent treatment. The purpose of this survey was to in- vestigate the percentage of potential temporomandibular dysfunctional patients seen as adolescents prior to orthodontic treatment.

Metltods and materials

Three hundred four patients were screened for routine orthodontic treat- ment in the Ohio State University Orthodontic Department. Ages ranged from 6 to 16 years, with a mean age of 12.9 years. There were 129 boys and 175 girls.

Sensitivity of the muscles of mastication was tested by palpation in each subject. The patient was requested to state whether pain was present and, if it was, to describe it as mild, moderate, or severe. The technique of Solberg 4 and Krough-

*Chairman, Department of Orthodontics, School of Dentistry, Medical College of Georgia.

429

430 Williamson Am. J. Orthod. October 1977

Fig. 1. A, Finger position for palpating the masseter muscles. 6, Temporalis palpation. All groups of fibers should be palpated separately.

Poulson5 was followed for palpation; that is, bilateral testing was done by the operator and the subject was asked to compare sides and then determine the degree of sensitivity (Fig. 1). The method of palpating the medial and lateral pterygoid muscles is most critical and, therefore, will be described here. The pa- tient was requested to open the mouth wide, and the operator’s index finger was moved along the anterior border of the ascending ramus. Near the level of the hamular notch, the tip of the finger was moved medially until the pterygoid hamulus could be palpated. The fingertip was then moved slightly posterior, and firm pressure was applied outward through an imaginary line passing through the center of the ear (Fig. 2). Pain to palpation in this area is usually indicative of sensitivity in either the medial or the lateral pterygoid muscles, or both. In order to discern the degree of pain in the lateral pterygoid only, the following technique was used: The operator’s index finger was placed posterior to the maxillary tuberosity in a manner similar to that used when a posterosuperior alveolar in- jection is given. The patient was asked to move his jaw to the side being palpated to allow more space for the fingertip. Firm pressure was then placed in a direction toward the infratemporal space, and the subject was asked to quantify any per- ceived pain. The medial pterygoid muscles were palpated by placing the opera- tor’s fingertip in the floor of the mouth near the third molar area. The gonial angle was supported extraorally by the other hand, and the operator’s intraoral finger was then able to apply pressure sublingually on the medial pterygoid insertion to the inner surface of the mandible.

Joint noises were also assessed by having the patient open and close with the operator’s fingers over the temporomandibular joint. Audible and digital sensa- tions were used by the investigator to determine the result. Angle classifications were determined, and assessment of open-bites or deep-bites was made. Open-bites were defined as no contact between maxillary and mandibular incisors or between the mandibular incisors and the palatal soft tissue. Deep-bites were defined as those anterior vertical overbites which equalled or exceeded 50 per cent.

TMJ dysfunction in pretreatment adolescents 431

Fig. 2. A, Palpation of the pterygoid complex. 9, Palpation of the lateral pterygoid muscle. C, Palpation of the medial pterygoid muscle.

Findings

Table I shows the symptomatic subjects and the asymptomatic ones catego- rized by Angle’s classification. Of 304 subjects screened, 107 were symptomatic. This amounted to 35.2 per cent with pain, clicking, or both, unilaterally or bi- laterally. There were forty-three boys and sixty-four girls with symptoms. Sixty- two had Class I malocclusion, thirty-nine had Class II, and six had Class III.

Table II indicates that, of the 107 symptomatic patients, nineteen had opten- bite and fifty-eight had 50 per cent or greater deep-bite. Table III shows the individual muscles involved and the frequency of involvement. The lateral ptery- goid muscles appear to be most often sensitive in dysfunctional patients, with the medial ptcrygoids being second. The massetcr is third in sensitivity.

Discussion

This survey immediately makes one aware of the critical circumstances under which the orthodontist is beginning treatment. It may be postulated that 35 per cent of the potential orthodontic patients, 6 to 16 years of age, seen by the practitioner have insipient temporomandibular joint dysfunction. It may also be observed that these patients usually have Class I or II malocclusions and that 72 per cent of the symptomatic subjects have either a deep-bite or an open-bite.

432 Williamson Am. J. O&hod. October 1977

Table I

Classification Pain

Symptomatic subjects (n = 107) Class I 35 Class II 25 Class III 1

Asymptomaticsubjects (n = 197) Class I Class II

Clicking Pain and clicking Total

I5 12 62 4 10 39 3 2 6

103 82

Class III 12

Table II

I Per cent of symptomatic No. I patients (n = 107)

Open-bites 50% or greater deep-bite Mean overiet

19 58

3.75 mm. range O-9

17.7 54.2

Table Ill

Muscles

Lateral pterygoids Medial pterygoids Masseter Temporalis

Individual muscles involved

Right Left

49 39 29 29 21 15 13 12

Total no. of subjects with muscle pain or clicking

Total

88 58 36 25

Muscles

Lateral pterygoids Medial pterygoids Masseter Temporalis Clicking

No. ofpatients Per cent of total Per cent o/symptomatic with pain (n = 304) (n = 107)

58 19.0 54.2 33 10.8 30.8 27 8.8 25.2 17 5.5 15.8 58 19.0 54.2

Overjet also appears to be a consideration, since the symptomatic subjects dis- played a mean of 3.75 mm. in this dimension.

Anterior guidance is a critical factor when a good functional occlusion is established. It provides a guide for the jaws anteriorly by way of the canines and incisor teeth. These teeth are anterior to the strong lever action of the muscles of mastication, and when immediate side shift is considered6 they can withstand the lateral forces inherent in this guiding system. The condyles ideally act as the posterior determinant of movement. When the posterior teeth are allowed to act as the most anterior functionrtl guides, a tendency toward defiec- tions and bruxism develops. The result may be dysfunction.

This investigation exemplifies the author’s clinical experience with adult dys-

TXJ dysfunction i l l prefrentnae?lt adolescents 433

functional patients. There seems to be a strong predisposition for these subjects to have high mandibular planes and Class II, Division 1 malocclusions with open- bites anteriorly or, on the contrary, deep-bite with a rather flat mandibular plane angle. The latter would be the Class II, Division 2 or Class I deep-bite eases with excessive anterior guidance. More girls than boys are seen for treatment.

The high degree of pterygoid muscle involvement can be explained. Thesr muscles are the most active in forward or lateral function of the mandible.‘-” Therefore, when tooth-induced deflections are present, the pterygoids must be- come overworked in order to accommodate the mandible to achieve maximum intercuspation. The lateral pterygoids are also the initial openers of the jaw.:-“’ When a locked-in deep-bite is present, those muscles must be overused in o-&l for the mandible to open before lateral function can be accomplished.

The most significant point to be learned from this survey is the need for a thorough diagnosis and an awareness by the orthodontist of potential temporo- mandibular joint dysfunction prior to initiat,ion of treatment. These patients need thoughtful care, and precise finishing must be provided when treatment is near completion. The records should be obviously marked for future reference.

The incipient joint problem at the ages of 6 to 16 will likely be the one overtly seen at the age of 30, whether orthodontic treatment has been rendered or not. It behooves the orthodontist to be alert and to realize which of his patients may have the tendency.

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