- Email: [email protected]
Longitudinal study of signs of temporomandibular disorders (TMD) in orthodontically treated and nontreated groups
Longitudinal study of signs of temporomandibular disorders (TMD) in orthodontically treated and nontreated groups Ronald H. Hirata," Marc W. Heft, b Belen Hernandez, ° and Gregory J. King ~ Gahlesville, Fla.
This study measured the prevalence and incidence of signs of temporomandibular (TM) disorders in both a group undergoing orthodontic treatment in the University of Florida graduate orthodontic program and a control group. A questionnaire pertaining to the patients' reports of signs and symptoms of TM disorder and a clinical examination were administered by a trained dental examiner. Data collection sessions occurred at baseline (before treatment) and at 12-month intervals to 24 months. Data were also collected for the control group at the same time intervals. There were 102 patients (43 boys, 59 girls) mean age 15.3 years. An untreated control group of 41 nonorthodontically treated subjects mean age 16.2 years was used. The incidence of TM signs for the treatment group and control group were not significantly different. Preliminary results are in agreement with the contention that orthodonticaliy treated patients are not more likely to develop TM signs while undergoing treatment. Results underscore the changing, inconstant, and ephemeral nature of TM signs in many persons over the course of time. (AMJ ORIHOO DENTOFACORTHOP 1992;101:35-40.)
T e m p o r o m a n d i b u l a r disorders (TMD) are characterized by one or more of the following signs and symptoms: joint noises (e.g., clicking or crepitus), pain (e.g., face pain), and irregularities of mandibular movement. 1-6.8,25 Epidemiologie studies of TMD show a wide range of prevalence of a priori signs in the populations studied. 2"4z'9z° Further reports on the occurrence of TMD signs and symptoms show variations in data collected from clinical examinations versus questionnaire data (anamnestic). Recently, there has been controversy in the literature with regard to the potential impact of orthodontic treatment on TMD. In 304 patients screened for orthodontie treatment, age range 6 to 16 years, mean 12.7 years, Williamson 7 found pain in the pterygoids on palpation, clicking, or both in 35% of the subjects screened. Kononen and colleagues t3 examined 166 Finnish children and found 52% of them had at least one symptom of TM disord e r - p a i n , reduction in opening, or TMJ sounds. A From the College of Dentistry, University of Florida. Supported by a grant from the American Association of Orthodontists. 'Department of Orthodontics; in private practice in Hawaii. ~Deparlment of Oral and Maxillofacial Surgery. CDepartment of Orthodontics; in private practice in Ponce, Puerto Rico. ~Department of Orthodontics. 8/1/32281
Japanese study involving 2198 children and adolescents (1095 boys and 1103 girls) from the 5th grade to high school found the prevalence of TMJ sounds to be 8.6%, pain in the TMJ region and masticatory muscles was 1.7%. Limitation of mandibular movement was found in 0.3%. Joint noises were by far the most common sign of TMD.t7 Studies in adults report similar high variability across studies. 2,9.2°-24 Schiffman and associates 23 found signs of TMD in 69% of the 269 female nursing students, ages 22 to 25 years. Forty-four percent had some type of joint noise. Investigating signs and symptoms of TMD in 739 students at the University of California at Los Angeles, age range 19 to 25 years, mean 22.5 years, Solberg et al. 2° found joint sounds in 28%. Ohno and associates t8 reported incidence of joint sound and pain in the TMJ region to be 6% and I% to 2%, respectively, in the adult Japanese. The prevalence of TMD in the population at large is difficult, if not impossible to determine, for the inconsistencies of the various studies in data collection methods, subjectivity of measurements, different measurements taken and data interpretationfl '5.24 The cause of TMD remains a subject of great controversy and is generally viewed as multifactorial. A few articles have implicated orthodontic treatment as a possible cause of TMD. 26"27Ricketts 26 stated that clin35
36
Hirata et al.
ical symptoms of joint derangement have been noted as occlusions were changed, and he suggested that the various orthodontic forces provided during therapy may predispose patients to temporomandibular joint problems. Other studies indicate that orthodontic treatment does not lead to increased occurrence of TMD. ~s34'4°".2 In a study by Sadowsky and BeGole 33 the status of TM joint function and functional occlusion was evaluated in 75 subjects who received treatment as adolescents 10 to 35 years previously. The findings suggested that in the orthodontically treated group, the prevalence of TMJ signs and symptoms were similar to those of untreated controls. Jason and Hasund u compared 60 previously treated patients who had Class II, Division 1 malocclusions 5 years out of retention (30 extraction and 30 nonextraction) with 30 matched untreated adults for TMJ signs and symptoms. The treated groups showed less TMD signs (e.g., deviation of closing, clicking, and crepitation). The nonextraction group showed fewer disturbances than the extraction group who, in turn, showed fewer disturbances than the nontreated control group. In two independent studies involving 96 patients (Illinois study) 32 and 111 patients (Eastman study), 32 who had comprehensive orthodontic treatment a minimum of 10 years previously, the investigators reported no significant difference in the incidence of signs and symptoms of TMD when compared with adults with untreated malocclusions. In the Illinois study, TMJ clicking was found in 34.4% of the orthodontic subjects and 41.8% in the untreated group; the Eastman study found 32.4% and 28.8% in the corresponding groups to have TMJ clicking. The orthodontic group in the Illinois study had fewer subjects with lateral shifts (9.4%) as compared with the control group 0 9 . 4 % ) at the 5% confidence level. The Eastman study found no significant differences in these parameters. The findings are in agreement with Larsson and Ronnerman 3° who studied symptoms of TMD in 23 patients who had completed orthodontic treatment 10 years earlier. The purpose of the present study was to assess the incidence of signs and symptoms of TMD in a longitudinal study of patients undergoing orthodontic treatment to evaluate the effects of orthodontic intervention on the temporal course o f the signs and symptoms of TMD. This article is part of an ongoing study of signs and symptoms of TMD in orthodontically treated subjects and focuses on several of the TMD signs.
METHODS Subjects The treatment group consisted of 102 subjects, 59 girls and 43 boys, mean age 15.3 years, undergoing full ortho-
Am. J. Orthod. Dentofac. Orthop. January 1992
dontic treatment in the graduate teaching clinic. There were no other inclusion criteria. A group of 41 subjects matched for age consisting of 20 girls and 21 boys, mean age 16.2 years, served as a control group.
Procedure Clinical measures of signs and symptoms of TM disorder were collected in the group undergoing comprehensive orthodontic treatment and in a matched control group. Baseline data (session 1) were collected for each person before initiation of orthodontic treatment. Follow-up data were collected at yearly intervals thereafter. Thus, for 60 of the 102 patients seen at baseline, third session data were collected approximately 2 years after baseline. Control group data were collected at only two sessions to date. Data collection sessions lasted approximately 30 minutes.
Questionnaire Before the clinical examination, the examiner completed a questionnaire with the patient covering general health, medications taken, past history of trauma or habits, and personal assessment of signs and/or symptoms of TMD.
Clinical examination Patients were seated in a dental chair in an upright position and the following were documented: Missing or unerupted teeth.Missing and unerupted teeth were charted visually and with the aid of a panoramic film. Maximal opening. Maximal opening was measured twice with a plastic millimeter ruler. The patients were instructed to open as wide as possible and were queried as to the limiting factor (mechanical or pain/discomfort). Deviation. The examiner was positioned behind the patient to determine deviations on opening and closing. Deviations of more than 3 mm while opening or closing were recorded, as were the direction and timing of occurrence (during opening, closing, or both). Maximum protrusion. Measurements were taken twice as the patient thrusted the mandible forward as far as it would go. Distance from the labial surface of the most labially placed mandibular central incisor to the most labially placed maxillary central incisor were recorded. Lateral movement. The midline of the mandibular incisors coincident with the maxillary midline (reference line) was marked with a pencil. Measurements were taken from the pencil mark to the maxillary midline as the patient was instructed to move the mandible maximally to the right and to the left. Midlines. Both maxillary and mandibular midlines were compared with the anatomic midline and recorded. Overjet. Overjet was measured from the labial surface of the most labially placed mandibular central incisor to the incisal edge of the most labially placed maxillary central incisor. Overbite. Overbite was measured using the mandibular central incisor which bad the most surface covered. The degree of overlap was measured from incisal edge of the man-
Voh,me 101 Number 1
Study of signs of TMD
37
Table I. Range of motion
Treatment group
I
T/ Mean age (rues) M a x i m u m open M a x i m u m open** M a x i m u m protrusion Right lateral Left lateral
185.8 48.8 52.3 8.6 9.1 9.1
- 8.0* -+- 0.59 --- 0.6 - 0.23 - 0.20 _ 0.24
Control
201.9 48.3 50.9 9.8 9.3 8.9
± ± --+ +-4
8.9 0.73 0.8 0.17 0.19 0.20
T3 208.6 50.0 52.2 9.4 9.7 9.3
I
T1
+-- 9.8 --+ 0.73 _-L-0.8 --- 0.27 --- 0.27 --- 0.24
195.3 52.0 54.9 6.1 8.9 8.8
72
+-- 5.2 +-- 0.74 --- 0.8 - 0.24 - 0.22 --- 0.24
225.8 52.2 55.2 8.2 8.6 10.0
4± -----
20.0 0.92 1.0 0.26 0.20 1.49
*SEM. **Correcting for overbite. T1, Time 1. 72, Time 2. T3, Time 3.
dibular central incisor to the point of maximal overlap of the maxillary central incisor. Johzt noises. The examiner was positioned behind the patient and instructed the patient to open and close several times palpating both condyles laterally and posteriorly with light finger pressure. Audible or palpatable joint "sounds" were documented as to location and type of sounds, as to whether on closing or opening, and as to beginning, middle, or end of the given cycle.
Table II. Joint sounds
Treatment Control
22% 41%
35%
Table I11.Joint sounds
RESULTS Patients' occlusions were classified with the Angle classification of malocclusion determined clinically and with the aid of models and photographic slides taken. There were 27 (26.5%) Class I, 68 (66.7%) Class II, and 7 (6.9%) Class III malocclusions in the experimental group; 18 (4.3%) Class I, 20 (48.8%) Class II, and 3 (7.3%) Class III malocclusions in the control group.
33.3% 31.7%
Treatment group History
T3
TI-T2
No
No-no No-yes Yes-no Yes-yes
29 6 2 ~
(48%) (10%) (3.3%) (3.3%)
a'OrAL
39 (65%)
l
Yes
l
Total
6 (10%) 9 (15%) 0 ~ (10%)
35 15 2 8
21 (35%)
60
(58%) (25%) (3.3%) (13.3%)
RANGE OF MOTION (Table I) Maximum mouth opening did not change over the sessions. M a x i m u m opening for the treatment group at baseline and two subsequent sessions were 49 m m ___ 0.6 SEM, 48 m m ± 0.7 SEM, and 50 m m ± 0.7 SEM, respectively, whereas that for the control group at baseline was 52 m m ± 0.7 SEM and session 2 was 52 m m ± 0.9 SEM. To compare with current literature, those open < 4 0 m m were 19.6% at baseline, 8.9% at T1, and 6.7% at T2 for the treated group; 5% at baseline and 4.9% at T I for the control. Maximum protrusion for the treatment group measured from 8.6 m m +- 0.2, 9.8 m m __- 0.2, and 9.4 m m ± 0.3 at baseline and two subsequent sessions, and for the control 6.1 mm ± 0.2 and 8.2 m m - 0.3 at baseline and session 2, respectively. Similarly, lateral excursions remained unchanged. Right lateral movements for the treatment group at base-
line and sessions 2 and 3 were 9.1 m m _ 0.2, 9.3 m m ± 0.2, and 9.7 m m ± 0.3, respectively, and the controls were 8.9 m m --- 0.2, and 8.6 mm ± 0.2, respectively. Similarly for left lateral movements for the treatment groups were 9.1 ( T I ) , 8.9 (T2), and 9.3 (T3). For controls, the left measurement were 8.8 at T I and 10.0 at T2.
JOINT SOUNDS (Tables II and III) Joint noise showed no pattern of change over time (Table II). For example, the control group, at baseline (41.5%) had joint noise. Measured approximately a year later, there was a slight decrease in those with sounds to 31.7%. Third session measurements were obtained for 60 o f the 102 treatment patients at the observed prevalence (Table III). Of these 60 patients,
38
Am. J. Orthod.Dentofac.Orthop. January 1992
Hirata et al.
Table IV. Deviation
Group Treatment Control
l
Baseline 33.3 % 34.0%
l
Tl 42.1% 51. ! %
l
T2 51.7%
23 (38%) had sounds at T2 (no-yes and yes-yes); of these 23, when examined the third time, 15 (25%) had sounds (no-yes-yes; yes-yes-yes).
DEVIATION (Table IV) There were no differences between treated and control groups with regard to observed deviations on open/closing. DISCUSSION Treatment group range of motion measurement in maximum opening, protrusion, and lateral movements corresponded well with those of the control group. There were no significant differences in the measurements between the two groups. These results were very similar to those obtained by Jason and Hasund 34 who compared 60 previously treated orthodontic patients with Class 1I, Division 1 malocclusions 5 years out of retention with 30 untreated adults for TMJ signs and symptoms and concluded that orthodontic treatment is not a functional risk to patients with Class II, Division I malocclusions. Of particular interest was the changeable nature of joint noises. Joint sounds are the most common finding in patients with temporomandibular disorders, 23'35 and in the general population. 7,9,t7.2° Temporomandibular joint clicking has been reported to occur in a wide range depending on study and methods u s e d . 7J7"2° In this study at baseline before treatment, the incidence of joint sounds was 22%. This was relatively low compared with 41% that was found in the control group at baseline, and in comparison with several recent studies. Gross and Gale ~ examined 1000 patients, age range 3 to 89 years, at random and found the frequency of joint clicking to be 31%. Solberg, Woo, and Houston 2° in examining 739 university students, age range 19 to 25 years, male-to-female ratio 50:50, found a 28.3% occurrence of joint sounds. Agerberg and Carlsson 36 in 1106 persons, ages 15 to 74 years (52% female) found incidence of joint sounds to be 39%. In a cross-sectional survey for TMJ sounds in 347 orthodontic patients before, during, and after treatment, Sadowsky and coinvestigators3~found TMJ sounds in 41% of the pretreatment group of 98 patients. Other studies show much lower prevalence. Nilner and Lassing" in
440 randomly selected Swedish children ages 7 to 14 years old found 8% to have clinically evident sounds. Ogura and colleagues ~7 found joint sounds to be the most common TMD symptom in 2198 Japanese children ages 10 to 18 years and in 8.6% of the total group. The observed change in joint sounds is similar to that found in other longitudinal studies, which detected changes both from no noises to noise and vice versa. In the study by Magnusson 37 that looked at changes in the course of time, it was found that approximately 50% of a group of 20-year-old patients with clicking had not shown the phenomenon at age 15 years, whereas nearly 50% of the 15-year-old patients with clicking no longer clicked at age 20 years. Van der Weele and Dibbets 43 observed 173 children (mean age 12.5 years) who underwent orthodontic treatment and examined them for joint noises and deformations of the condyle before orthodontic treatment and yearly thereafter for 4 years, then 10 years after the start of treatment. These investigators found that for a substantial number of patients the symptoms often appeared and disappeared during the course of the study. Even the increasing frequencies were characterized by a large number of "drop outs," that is, children no longer evidencing symptoms. In a longitudinal study of clinical signs of mandibular dysfunction Gross and Gale 3s examined 175 patients who did not have symptoms or pain over periods of 3 days to 18 months. Results showed that 37.2% of the patients demonstrated at least one change in a clinical sign over time. Joint sounds and deviations were the most variable. A similar trend continued in our preliminary findings in 60 patients we followed during a 2-year period. A year after their initial examination, the incidence of joint sound was 38.3%. Measured approximately a year later, the prevalence of sounds was 35%. On closer examination, these were made up of 10% of the patients who had no sounds during the first two sessions, 10% of the patients who had sounds before treatment, and 15% of the patients in whom sounds were detected approximately a year after initial examination. Interestingly, the patients without joint noise during the 2year follow-up were made up of 29 (48%) in whom no sounds were detected throughout the treatment course, 6 (10%) in whom sounds were evident during the first follow-up session, 2 (3.3%) who started with sounds, but has been without since the first follow-up, and 2 (3.3%) who had sounds during the first two sessions. The occurrence of joint sounds in our study compares closely with findings in other studies. Runge and others 39 in investigating joint sounds and types of malocclusion in 226 patients presenting for orthodontic
Voh,me 10l Number 1 t r e a t m e n t , f o u n d 3 6 . 6 % h a d j o i n t s o u n d s . O u r results d u r i n g t r e a t m e n t at the first f o l l o w - u p s e s s i o n are c o m p a r e d w i t h the f i n d i n g s o f S a d o w s k i a n d P o l s o n 32 in f o r m e r p a t i e n t s w h o h a d u n d e r g o n e o r t h o d o n t i c treatm e n t a m i n i m u m o f 10 y e a r s p r e v i o u s l y . T h e results o f S a d o w s k i a n d P o i s o n ( E a s t m a n a n d Illinois studies) s h o w e d n o s i g n i f i c a n t d i f f e r e n c e s in the i n c i d e n c e o f T M D s i g n s a n d s y m p t o m s b e t w e e n t h o s e treated o r t h o d o n t i c a l l y a n d the u n t r e a t e d c o n t r o l s . P r e l i m i n a r y f i n d i n g s , o f this o n g o i n g s t u d y s u p p o r t the c o n t e n t i o n t h a t o r t h o d o n t i c t r e a t m e n t n e i t h e r increases nor decreases incidence of signs of TMD. Our f i n d i n g s u n d e r s c o r e the v a r i a b i l i t y in signs o f T M D , a n d the p o s s i b i l i t y t h a t m a n y o f t h e a priori signs o f T M D m a y not h a v e clinical s i g n i f i c a n c e .
REFERENCES 1. Perry HT. The symptomotology of temporomandibular joint disturbances. J Prosthet Dent 1968;29:288-98. 2. Heft MW. Prevalence of temporomandibular joint signs and symptoms in the elderly. Gerontol~y 1984;3:125-30. 3. Laskin DM. Etiol~y of pain dysfunction syndrome. J Am Dent Assoc 1969;79:147-53. 4. Agerberg G, Carlsson GE. Functional disorders of the masticatory system: distribution of symptoms according to age and sex as judged from investigation by questionnaire. Acta Odontol Scand 1972;30:597-613. 5. Gross A, Gale E. A prevalence study of the clinical signs associated with mandibular dysfunction. J Am Dent Assoc 1983;107:932-6. 6. Brandt D, lngermark-Eriksson 1. Temporomandibular disorders and their association with morphol~ie malocclusion in children. In: Carlson DS, McNamara JA, Ribbens KA, eds. Developmental aspects of temporomandibular disorders. Monograph 16, Craniofacial Growth Series. Ann Arbor: Center for Human Growth and Development, University of Michigan, 1985. 7. Williamson EH. Temporomandibular dysfunction in pretreatment adolescent patients. A.',~ J ORmoo 1977;72:429-33. 8. Greene CS. Temporomandibular joint disorders in clinical dentistry. Vol. 2. Philadelphia: Harper and Row, 1984. 9. Hansson T, Nilner M. A study of the occurrence of symptoms of diseases of the TMJ masticatory musculature and related structures. J Oral Rehabil 1975;2:313-24. 10. Grosfeld O, Jackowska M, Czamecka B. Results of epidemiological examination of the TMJ in adolescents and young adults. J Oral Rehabil 1985;12:95-105. 1I. Nilner M, Lassing S. Prevalence of functional disturbances and diseases of the stomatognathic system in 7-14 year olds. Swed Dent J 1980;174-87. 12. Nilner hi. Prevalence of functional disturbances and disease of the stomatognathic system in 15-18 year olds. Swed Dent J 1981;5:189-97. 13. Kononen M, Nystrom M, Kleemola-Kujola E, Kataja M, Evalahti M, Pekka L, Peck L. Signs and symptoms of craniomandibular disorders in a series of Finnish children. Acta Odontol Scand 1987;45:109-14. 14. Egermark-Eriksson I, Carlsson GE, Ingervall B. Prevalence of mandibular dysfunction and orofacial parafunction in 7-11 and 15 year old Swedish children. Eur J Orthod 1981;3:163-72. 15. Egermark-Erikson I. Malocclusion and some functional record-
Stttdy of signs of TMD
16. 17.
18.
19.
20. 21.
22.
23.
24.
25. 26. 27. 28. 29. 30.
31.
32.
33.
34. 35.
36.
37.
39
ings of the masticatory system in Swedish school children. Swed Dent J 1982;6:9-20. Vanderas AP. Prevalence of craniomandibular dysfunction in children and adults: a review. Pediatr Dent t987;9:312-6. Ogura T, Morinushi T, Ohno H, Sumi K, Hatada K. An epidemiol~ical study of TMJ dysfunction syndrome in adolescents. J Pedodontics 1985;10:22-35. Ohno H, hlorinushi T, Ohno K, Ogura T. Comparative subjective evaluation and prevalence study of TMJ dysfunction syndrome in Japanese adolescents based On clinical examination. Community Dent Oral Epidemiol 1988;16:122-6. Grosfeld O, Czarnecka B. Musculo-articular disorders of the stomat~nathie system in school children examined according to clinical criteria. J Oral Rehabil 1977;14:193-200. Solberg WK, Woo MW, ttouston JB. Prevalence of mandibular dysfunction in young adults. J Am Dent Assoc 1979;98:25-34. Ingervall B, Mohlin B, Thilander B. Prevalence of symptoms of functional disturbances of the masticatory system in Swedish men. J Oral Rehabil 1980;7:185-97. Heloe B, Heloe LA. Frequency and distribution of myofascial pain dysfunction syndrome in a population of 25 year-olds. Community Dent Oral Epidemiol 1979;7:357-60. Shiffman EL, Fricton JR, Haley DP, Shapiro BL. The prevalence and treatment needs of subjects with TM disorders. J Am Dent Assoc 1990;120:295-303. Dworkin SF, Huggins KH, LeResche L, VonKorff M, Howard J, Truelove E, Sommers E. Epidemiol~y of signs and symptoms in TM disorders: clinical signs in cases and controls. J Am Dent Assoc 1990;120:273-81. Goldstein DF, Kraus SL, Williams WB. Influence of cervical posture on mandibular movement. J Prosthet Dent 1984;52:421. Ricketts RM. Clinical implications of the temporomandibular mandibular joint. A.~t J ORTHOD 1966;52:416-39. Roth RH. Temporomandibular pain-dysfunction and occlusal relationships. Angle Orthod 1973;43:136-52. Greene CS. Orthodontics and temporomandibular disorders. Dent Clin North Am 1988;32:522-38. Greene CS. Orthodontics and the TM joint. Angle Orthod 1982;52:166-72. Larsson E, Ronnermen A. Mandibular dysfunction symptoms in orthodontically treated patients 10 years after completion of the treatment. Eur J Orthod 1981;3:89-94. Magnusson T, Enbom L. Signs and symptoms of mandibular dysfunction after introduction of experimental balancing-side interferences. Acta Odontol Scand 1984;42:129-35. Sadowsky C, Poison AM. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long term studies. AM J ORTHOD 1984;86:386-90. Sadowsky C, BeGole EA. Long term status of temporomandibular joint function and functional occlusion after orthodontic treatment. AM J ORTHOD 1980;78:201-12. Janson M, Hasund A. Functional problems in orthodontic patients out of retention. Eur J Orthod 1981;3:173-9. Sadowsky C, Muhl ZF, Sakols El, Sommerville JM. Temporomandibular joint sounds related to orthodontic therapy. J Dent Res 1985;64(12):1392-5. Agerberg G, Carlsson GE. Symptoms of functional disturbances of the masticating system. A comparison of frequencies in a population sample and in a group of patients. Acta Odontol Scand 1975;33:183-90. Magnusson T, Egermark-Eriksson I, Carlsson GE. 5-year longitudinal study of signs and symptoms of mandibular dysfunction in adolescents. J Craniomandib Pract 1986;4:339-43.
40
Hirata et al.
Am. J. Orthod. Dentofac. Orthop. January 1992
38. Gross A, Gale EN. Longitudinalstudy of clinical signs of mandibular dysfunction.AADR Abstracts 1983;168:188. 39. Runge ME, Sadowsky C, Sakols El, BeGold EA. The relationship betweentemporomandibularsounds and malocclusion.A.',t J ORTHODDENTOFACORTIIOP1989;96:36-42. 40. SadowskyC, TheisenTA, Sakols El. Orthodontictreatmentand temporomandibularjoint sounds. A longitudinal study. AM J ORTIIODDENTOFACORTHOP1991;99:441-7. 41. Dibbets JMH, van der Weele LTh. Orthodontic treatment in relation to symptoms attributed to dysfunctionof the temporomandibularjoint. AM J ORTtlODDEmOFACOR'I'HOP1987;91: 193-9. 42. DibbetsJMH, van der Weele LTh. Extraction,orthodontictreat-
ment, and craniomandibulardysfunction. AM J ORTHODDENTOFACORVHOr'1991;99:210-9. 43. van der Weele LTh, Dibbets JMH. Conceptualmodels for analyzing symptoms of temporomandibular joint dysfunction. J CraniomandibPract 1986;4:358-66.
Reprint requests to:
Dr. Gregory J. King Department of Orthodontics Universityof Florida School of Dentistry JHMHC, Box J-444 Gainesville,FL 32610
BOUND VOLUMES AVAILABLE TO SUBSCRIBERS
Bound volumes of the AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS are available to subscribers (only) for the 1992 issues from the Publisher, at a cost of $53.00 ($67.71 Canada and $64.00 international) for Vol. 101 (January-June) and Vol. 102 (July-December). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. P a y m e n t m u s t a c c o m p a n y a l l o r d e r s . Contact M o s b y - Y e a r Book, Inc., Subscription Services, 11830 Westline Industrial Drive, St. Louis, MO 63146-3318, USA; telephone (314)453-4351 or (800)325-4177.
Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular Journal subscription.
This study measured the prevalence and incidence of signs of temporomandibular (TM) disorders in both a group undergoing orthodontic treatment in the University of Florida graduate orthodontic program and a control group. A questionnaire pertaining to the patients' reports of signs and symptoms of TM disorder and a clinical examination were administered by a trained dental examiner. Data collection sessions occurred at baseline (before treatment) and at 12-month intervals to 24 months. Data were also collected for the control group at the same time intervals. There were 102 patients (43 boys, 59 girls) mean age 15.3 years. An untreated control group of 41 nonorthodontically treated subjects mean age 16.2 years was used. The incidence of TM signs for the treatment group and control group were not significantly different. Preliminary results are in agreement with the contention that orthodonticaliy treated patients are not more likely to develop TM signs while undergoing treatment. Results underscore the changing, inconstant, and ephemeral nature of TM signs in many persons over the course of time. (AMJ ORIHOO DENTOFACORTHOP 1992;101:35-40.)
T e m p o r o m a n d i b u l a r disorders (TMD) are characterized by one or more of the following signs and symptoms: joint noises (e.g., clicking or crepitus), pain (e.g., face pain), and irregularities of mandibular movement. 1-6.8,25 Epidemiologie studies of TMD show a wide range of prevalence of a priori signs in the populations studied. 2"4z'9z° Further reports on the occurrence of TMD signs and symptoms show variations in data collected from clinical examinations versus questionnaire data (anamnestic). Recently, there has been controversy in the literature with regard to the potential impact of orthodontic treatment on TMD. In 304 patients screened for orthodontie treatment, age range 6 to 16 years, mean 12.7 years, Williamson 7 found pain in the pterygoids on palpation, clicking, or both in 35% of the subjects screened. Kononen and colleagues t3 examined 166 Finnish children and found 52% of them had at least one symptom of TM disord e r - p a i n , reduction in opening, or TMJ sounds. A From the College of Dentistry, University of Florida. Supported by a grant from the American Association of Orthodontists. 'Department of Orthodontics; in private practice in Hawaii. ~Deparlment of Oral and Maxillofacial Surgery. CDepartment of Orthodontics; in private practice in Ponce, Puerto Rico. ~Department of Orthodontics. 8/1/32281
Japanese study involving 2198 children and adolescents (1095 boys and 1103 girls) from the 5th grade to high school found the prevalence of TMJ sounds to be 8.6%, pain in the TMJ region and masticatory muscles was 1.7%. Limitation of mandibular movement was found in 0.3%. Joint noises were by far the most common sign of TMD.t7 Studies in adults report similar high variability across studies. 2,9.2°-24 Schiffman and associates 23 found signs of TMD in 69% of the 269 female nursing students, ages 22 to 25 years. Forty-four percent had some type of joint noise. Investigating signs and symptoms of TMD in 739 students at the University of California at Los Angeles, age range 19 to 25 years, mean 22.5 years, Solberg et al. 2° found joint sounds in 28%. Ohno and associates t8 reported incidence of joint sound and pain in the TMJ region to be 6% and I% to 2%, respectively, in the adult Japanese. The prevalence of TMD in the population at large is difficult, if not impossible to determine, for the inconsistencies of the various studies in data collection methods, subjectivity of measurements, different measurements taken and data interpretationfl '5.24 The cause of TMD remains a subject of great controversy and is generally viewed as multifactorial. A few articles have implicated orthodontic treatment as a possible cause of TMD. 26"27Ricketts 26 stated that clin35
36
Hirata et al.
ical symptoms of joint derangement have been noted as occlusions were changed, and he suggested that the various orthodontic forces provided during therapy may predispose patients to temporomandibular joint problems. Other studies indicate that orthodontic treatment does not lead to increased occurrence of TMD. ~s34'4°".2 In a study by Sadowsky and BeGole 33 the status of TM joint function and functional occlusion was evaluated in 75 subjects who received treatment as adolescents 10 to 35 years previously. The findings suggested that in the orthodontically treated group, the prevalence of TMJ signs and symptoms were similar to those of untreated controls. Jason and Hasund u compared 60 previously treated patients who had Class II, Division 1 malocclusions 5 years out of retention (30 extraction and 30 nonextraction) with 30 matched untreated adults for TMJ signs and symptoms. The treated groups showed less TMD signs (e.g., deviation of closing, clicking, and crepitation). The nonextraction group showed fewer disturbances than the extraction group who, in turn, showed fewer disturbances than the nontreated control group. In two independent studies involving 96 patients (Illinois study) 32 and 111 patients (Eastman study), 32 who had comprehensive orthodontic treatment a minimum of 10 years previously, the investigators reported no significant difference in the incidence of signs and symptoms of TMD when compared with adults with untreated malocclusions. In the Illinois study, TMJ clicking was found in 34.4% of the orthodontic subjects and 41.8% in the untreated group; the Eastman study found 32.4% and 28.8% in the corresponding groups to have TMJ clicking. The orthodontic group in the Illinois study had fewer subjects with lateral shifts (9.4%) as compared with the control group 0 9 . 4 % ) at the 5% confidence level. The Eastman study found no significant differences in these parameters. The findings are in agreement with Larsson and Ronnerman 3° who studied symptoms of TMD in 23 patients who had completed orthodontic treatment 10 years earlier. The purpose of the present study was to assess the incidence of signs and symptoms of TMD in a longitudinal study of patients undergoing orthodontic treatment to evaluate the effects of orthodontic intervention on the temporal course o f the signs and symptoms of TMD. This article is part of an ongoing study of signs and symptoms of TMD in orthodontically treated subjects and focuses on several of the TMD signs.
METHODS Subjects The treatment group consisted of 102 subjects, 59 girls and 43 boys, mean age 15.3 years, undergoing full ortho-
Am. J. Orthod. Dentofac. Orthop. January 1992
dontic treatment in the graduate teaching clinic. There were no other inclusion criteria. A group of 41 subjects matched for age consisting of 20 girls and 21 boys, mean age 16.2 years, served as a control group.
Procedure Clinical measures of signs and symptoms of TM disorder were collected in the group undergoing comprehensive orthodontic treatment and in a matched control group. Baseline data (session 1) were collected for each person before initiation of orthodontic treatment. Follow-up data were collected at yearly intervals thereafter. Thus, for 60 of the 102 patients seen at baseline, third session data were collected approximately 2 years after baseline. Control group data were collected at only two sessions to date. Data collection sessions lasted approximately 30 minutes.
Questionnaire Before the clinical examination, the examiner completed a questionnaire with the patient covering general health, medications taken, past history of trauma or habits, and personal assessment of signs and/or symptoms of TMD.
Clinical examination Patients were seated in a dental chair in an upright position and the following were documented: Missing or unerupted teeth.Missing and unerupted teeth were charted visually and with the aid of a panoramic film. Maximal opening. Maximal opening was measured twice with a plastic millimeter ruler. The patients were instructed to open as wide as possible and were queried as to the limiting factor (mechanical or pain/discomfort). Deviation. The examiner was positioned behind the patient to determine deviations on opening and closing. Deviations of more than 3 mm while opening or closing were recorded, as were the direction and timing of occurrence (during opening, closing, or both). Maximum protrusion. Measurements were taken twice as the patient thrusted the mandible forward as far as it would go. Distance from the labial surface of the most labially placed mandibular central incisor to the most labially placed maxillary central incisor were recorded. Lateral movement. The midline of the mandibular incisors coincident with the maxillary midline (reference line) was marked with a pencil. Measurements were taken from the pencil mark to the maxillary midline as the patient was instructed to move the mandible maximally to the right and to the left. Midlines. Both maxillary and mandibular midlines were compared with the anatomic midline and recorded. Overjet. Overjet was measured from the labial surface of the most labially placed mandibular central incisor to the incisal edge of the most labially placed maxillary central incisor. Overbite. Overbite was measured using the mandibular central incisor which bad the most surface covered. The degree of overlap was measured from incisal edge of the man-
Voh,me 101 Number 1
Study of signs of TMD
37
Table I. Range of motion
Treatment group
I
T/ Mean age (rues) M a x i m u m open M a x i m u m open** M a x i m u m protrusion Right lateral Left lateral
185.8 48.8 52.3 8.6 9.1 9.1
- 8.0* -+- 0.59 --- 0.6 - 0.23 - 0.20 _ 0.24
Control
201.9 48.3 50.9 9.8 9.3 8.9
± ± --+ +-4
8.9 0.73 0.8 0.17 0.19 0.20
T3 208.6 50.0 52.2 9.4 9.7 9.3
I
T1
+-- 9.8 --+ 0.73 _-L-0.8 --- 0.27 --- 0.27 --- 0.24
195.3 52.0 54.9 6.1 8.9 8.8
72
+-- 5.2 +-- 0.74 --- 0.8 - 0.24 - 0.22 --- 0.24
225.8 52.2 55.2 8.2 8.6 10.0
4± -----
20.0 0.92 1.0 0.26 0.20 1.49
*SEM. **Correcting for overbite. T1, Time 1. 72, Time 2. T3, Time 3.
dibular central incisor to the point of maximal overlap of the maxillary central incisor. Johzt noises. The examiner was positioned behind the patient and instructed the patient to open and close several times palpating both condyles laterally and posteriorly with light finger pressure. Audible or palpatable joint "sounds" were documented as to location and type of sounds, as to whether on closing or opening, and as to beginning, middle, or end of the given cycle.
Table II. Joint sounds
Treatment Control
22% 41%
35%
Table I11.Joint sounds
RESULTS Patients' occlusions were classified with the Angle classification of malocclusion determined clinically and with the aid of models and photographic slides taken. There were 27 (26.5%) Class I, 68 (66.7%) Class II, and 7 (6.9%) Class III malocclusions in the experimental group; 18 (4.3%) Class I, 20 (48.8%) Class II, and 3 (7.3%) Class III malocclusions in the control group.
33.3% 31.7%
Treatment group History
T3
TI-T2
No
No-no No-yes Yes-no Yes-yes
29 6 2 ~
(48%) (10%) (3.3%) (3.3%)
a'OrAL
39 (65%)
l
Yes
l
Total
6 (10%) 9 (15%) 0 ~ (10%)
35 15 2 8
21 (35%)
60
(58%) (25%) (3.3%) (13.3%)
RANGE OF MOTION (Table I) Maximum mouth opening did not change over the sessions. M a x i m u m opening for the treatment group at baseline and two subsequent sessions were 49 m m ___ 0.6 SEM, 48 m m ± 0.7 SEM, and 50 m m ± 0.7 SEM, respectively, whereas that for the control group at baseline was 52 m m ± 0.7 SEM and session 2 was 52 m m ± 0.9 SEM. To compare with current literature, those open < 4 0 m m were 19.6% at baseline, 8.9% at T1, and 6.7% at T2 for the treated group; 5% at baseline and 4.9% at T I for the control. Maximum protrusion for the treatment group measured from 8.6 m m +- 0.2, 9.8 m m __- 0.2, and 9.4 m m ± 0.3 at baseline and two subsequent sessions, and for the control 6.1 mm ± 0.2 and 8.2 m m - 0.3 at baseline and session 2, respectively. Similarly, lateral excursions remained unchanged. Right lateral movements for the treatment group at base-
line and sessions 2 and 3 were 9.1 m m _ 0.2, 9.3 m m ± 0.2, and 9.7 m m ± 0.3, respectively, and the controls were 8.9 m m --- 0.2, and 8.6 mm ± 0.2, respectively. Similarly for left lateral movements for the treatment groups were 9.1 ( T I ) , 8.9 (T2), and 9.3 (T3). For controls, the left measurement were 8.8 at T I and 10.0 at T2.
JOINT SOUNDS (Tables II and III) Joint noise showed no pattern of change over time (Table II). For example, the control group, at baseline (41.5%) had joint noise. Measured approximately a year later, there was a slight decrease in those with sounds to 31.7%. Third session measurements were obtained for 60 o f the 102 treatment patients at the observed prevalence (Table III). Of these 60 patients,
38
Am. J. Orthod.Dentofac.Orthop. January 1992
Hirata et al.
Table IV. Deviation
Group Treatment Control
l
Baseline 33.3 % 34.0%
l
Tl 42.1% 51. ! %
l
T2 51.7%
23 (38%) had sounds at T2 (no-yes and yes-yes); of these 23, when examined the third time, 15 (25%) had sounds (no-yes-yes; yes-yes-yes).
DEVIATION (Table IV) There were no differences between treated and control groups with regard to observed deviations on open/closing. DISCUSSION Treatment group range of motion measurement in maximum opening, protrusion, and lateral movements corresponded well with those of the control group. There were no significant differences in the measurements between the two groups. These results were very similar to those obtained by Jason and Hasund 34 who compared 60 previously treated orthodontic patients with Class 1I, Division 1 malocclusions 5 years out of retention with 30 untreated adults for TMJ signs and symptoms and concluded that orthodontic treatment is not a functional risk to patients with Class II, Division I malocclusions. Of particular interest was the changeable nature of joint noises. Joint sounds are the most common finding in patients with temporomandibular disorders, 23'35 and in the general population. 7,9,t7.2° Temporomandibular joint clicking has been reported to occur in a wide range depending on study and methods u s e d . 7J7"2° In this study at baseline before treatment, the incidence of joint sounds was 22%. This was relatively low compared with 41% that was found in the control group at baseline, and in comparison with several recent studies. Gross and Gale ~ examined 1000 patients, age range 3 to 89 years, at random and found the frequency of joint clicking to be 31%. Solberg, Woo, and Houston 2° in examining 739 university students, age range 19 to 25 years, male-to-female ratio 50:50, found a 28.3% occurrence of joint sounds. Agerberg and Carlsson 36 in 1106 persons, ages 15 to 74 years (52% female) found incidence of joint sounds to be 39%. In a cross-sectional survey for TMJ sounds in 347 orthodontic patients before, during, and after treatment, Sadowsky and coinvestigators3~found TMJ sounds in 41% of the pretreatment group of 98 patients. Other studies show much lower prevalence. Nilner and Lassing" in
440 randomly selected Swedish children ages 7 to 14 years old found 8% to have clinically evident sounds. Ogura and colleagues ~7 found joint sounds to be the most common TMD symptom in 2198 Japanese children ages 10 to 18 years and in 8.6% of the total group. The observed change in joint sounds is similar to that found in other longitudinal studies, which detected changes both from no noises to noise and vice versa. In the study by Magnusson 37 that looked at changes in the course of time, it was found that approximately 50% of a group of 20-year-old patients with clicking had not shown the phenomenon at age 15 years, whereas nearly 50% of the 15-year-old patients with clicking no longer clicked at age 20 years. Van der Weele and Dibbets 43 observed 173 children (mean age 12.5 years) who underwent orthodontic treatment and examined them for joint noises and deformations of the condyle before orthodontic treatment and yearly thereafter for 4 years, then 10 years after the start of treatment. These investigators found that for a substantial number of patients the symptoms often appeared and disappeared during the course of the study. Even the increasing frequencies were characterized by a large number of "drop outs," that is, children no longer evidencing symptoms. In a longitudinal study of clinical signs of mandibular dysfunction Gross and Gale 3s examined 175 patients who did not have symptoms or pain over periods of 3 days to 18 months. Results showed that 37.2% of the patients demonstrated at least one change in a clinical sign over time. Joint sounds and deviations were the most variable. A similar trend continued in our preliminary findings in 60 patients we followed during a 2-year period. A year after their initial examination, the incidence of joint sound was 38.3%. Measured approximately a year later, the prevalence of sounds was 35%. On closer examination, these were made up of 10% of the patients who had no sounds during the first two sessions, 10% of the patients who had sounds before treatment, and 15% of the patients in whom sounds were detected approximately a year after initial examination. Interestingly, the patients without joint noise during the 2year follow-up were made up of 29 (48%) in whom no sounds were detected throughout the treatment course, 6 (10%) in whom sounds were evident during the first follow-up session, 2 (3.3%) who started with sounds, but has been without since the first follow-up, and 2 (3.3%) who had sounds during the first two sessions. The occurrence of joint sounds in our study compares closely with findings in other studies. Runge and others 39 in investigating joint sounds and types of malocclusion in 226 patients presenting for orthodontic
Voh,me 10l Number 1 t r e a t m e n t , f o u n d 3 6 . 6 % h a d j o i n t s o u n d s . O u r results d u r i n g t r e a t m e n t at the first f o l l o w - u p s e s s i o n are c o m p a r e d w i t h the f i n d i n g s o f S a d o w s k i a n d P o l s o n 32 in f o r m e r p a t i e n t s w h o h a d u n d e r g o n e o r t h o d o n t i c treatm e n t a m i n i m u m o f 10 y e a r s p r e v i o u s l y . T h e results o f S a d o w s k i a n d P o i s o n ( E a s t m a n a n d Illinois studies) s h o w e d n o s i g n i f i c a n t d i f f e r e n c e s in the i n c i d e n c e o f T M D s i g n s a n d s y m p t o m s b e t w e e n t h o s e treated o r t h o d o n t i c a l l y a n d the u n t r e a t e d c o n t r o l s . P r e l i m i n a r y f i n d i n g s , o f this o n g o i n g s t u d y s u p p o r t the c o n t e n t i o n t h a t o r t h o d o n t i c t r e a t m e n t n e i t h e r increases nor decreases incidence of signs of TMD. Our f i n d i n g s u n d e r s c o r e the v a r i a b i l i t y in signs o f T M D , a n d the p o s s i b i l i t y t h a t m a n y o f t h e a priori signs o f T M D m a y not h a v e clinical s i g n i f i c a n c e .
REFERENCES 1. Perry HT. The symptomotology of temporomandibular joint disturbances. J Prosthet Dent 1968;29:288-98. 2. Heft MW. Prevalence of temporomandibular joint signs and symptoms in the elderly. Gerontol~y 1984;3:125-30. 3. Laskin DM. Etiol~y of pain dysfunction syndrome. J Am Dent Assoc 1969;79:147-53. 4. Agerberg G, Carlsson GE. Functional disorders of the masticatory system: distribution of symptoms according to age and sex as judged from investigation by questionnaire. Acta Odontol Scand 1972;30:597-613. 5. Gross A, Gale E. A prevalence study of the clinical signs associated with mandibular dysfunction. J Am Dent Assoc 1983;107:932-6. 6. Brandt D, lngermark-Eriksson 1. Temporomandibular disorders and their association with morphol~ie malocclusion in children. In: Carlson DS, McNamara JA, Ribbens KA, eds. Developmental aspects of temporomandibular disorders. Monograph 16, Craniofacial Growth Series. Ann Arbor: Center for Human Growth and Development, University of Michigan, 1985. 7. Williamson EH. Temporomandibular dysfunction in pretreatment adolescent patients. A.',~ J ORmoo 1977;72:429-33. 8. Greene CS. Temporomandibular joint disorders in clinical dentistry. Vol. 2. Philadelphia: Harper and Row, 1984. 9. Hansson T, Nilner M. A study of the occurrence of symptoms of diseases of the TMJ masticatory musculature and related structures. J Oral Rehabil 1975;2:313-24. 10. Grosfeld O, Jackowska M, Czamecka B. Results of epidemiological examination of the TMJ in adolescents and young adults. J Oral Rehabil 1985;12:95-105. 1I. Nilner M, Lassing S. Prevalence of functional disturbances and diseases of the stomatognathic system in 7-14 year olds. Swed Dent J 1980;174-87. 12. Nilner hi. Prevalence of functional disturbances and disease of the stomatognathic system in 15-18 year olds. Swed Dent J 1981;5:189-97. 13. Kononen M, Nystrom M, Kleemola-Kujola E, Kataja M, Evalahti M, Pekka L, Peck L. Signs and symptoms of craniomandibular disorders in a series of Finnish children. Acta Odontol Scand 1987;45:109-14. 14. Egermark-Eriksson I, Carlsson GE, Ingervall B. Prevalence of mandibular dysfunction and orofacial parafunction in 7-11 and 15 year old Swedish children. Eur J Orthod 1981;3:163-72. 15. Egermark-Erikson I. Malocclusion and some functional record-
Stttdy of signs of TMD
16. 17.
18.
19.
20. 21.
22.
23.
24.
25. 26. 27. 28. 29. 30.
31.
32.
33.
34. 35.
36.
37.
39
ings of the masticatory system in Swedish school children. Swed Dent J 1982;6:9-20. Vanderas AP. Prevalence of craniomandibular dysfunction in children and adults: a review. Pediatr Dent t987;9:312-6. Ogura T, Morinushi T, Ohno H, Sumi K, Hatada K. An epidemiol~ical study of TMJ dysfunction syndrome in adolescents. J Pedodontics 1985;10:22-35. Ohno H, hlorinushi T, Ohno K, Ogura T. Comparative subjective evaluation and prevalence study of TMJ dysfunction syndrome in Japanese adolescents based On clinical examination. Community Dent Oral Epidemiol 1988;16:122-6. Grosfeld O, Czarnecka B. Musculo-articular disorders of the stomat~nathie system in school children examined according to clinical criteria. J Oral Rehabil 1977;14:193-200. Solberg WK, Woo MW, ttouston JB. Prevalence of mandibular dysfunction in young adults. J Am Dent Assoc 1979;98:25-34. Ingervall B, Mohlin B, Thilander B. Prevalence of symptoms of functional disturbances of the masticatory system in Swedish men. J Oral Rehabil 1980;7:185-97. Heloe B, Heloe LA. Frequency and distribution of myofascial pain dysfunction syndrome in a population of 25 year-olds. Community Dent Oral Epidemiol 1979;7:357-60. Shiffman EL, Fricton JR, Haley DP, Shapiro BL. The prevalence and treatment needs of subjects with TM disorders. J Am Dent Assoc 1990;120:295-303. Dworkin SF, Huggins KH, LeResche L, VonKorff M, Howard J, Truelove E, Sommers E. Epidemiol~y of signs and symptoms in TM disorders: clinical signs in cases and controls. J Am Dent Assoc 1990;120:273-81. Goldstein DF, Kraus SL, Williams WB. Influence of cervical posture on mandibular movement. J Prosthet Dent 1984;52:421. Ricketts RM. Clinical implications of the temporomandibular mandibular joint. A.~t J ORTHOD 1966;52:416-39. Roth RH. Temporomandibular pain-dysfunction and occlusal relationships. Angle Orthod 1973;43:136-52. Greene CS. Orthodontics and temporomandibular disorders. Dent Clin North Am 1988;32:522-38. Greene CS. Orthodontics and the TM joint. Angle Orthod 1982;52:166-72. Larsson E, Ronnermen A. Mandibular dysfunction symptoms in orthodontically treated patients 10 years after completion of the treatment. Eur J Orthod 1981;3:89-94. Magnusson T, Enbom L. Signs and symptoms of mandibular dysfunction after introduction of experimental balancing-side interferences. Acta Odontol Scand 1984;42:129-35. Sadowsky C, Poison AM. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long term studies. AM J ORTHOD 1984;86:386-90. Sadowsky C, BeGole EA. Long term status of temporomandibular joint function and functional occlusion after orthodontic treatment. AM J ORTHOD 1980;78:201-12. Janson M, Hasund A. Functional problems in orthodontic patients out of retention. Eur J Orthod 1981;3:173-9. Sadowsky C, Muhl ZF, Sakols El, Sommerville JM. Temporomandibular joint sounds related to orthodontic therapy. J Dent Res 1985;64(12):1392-5. Agerberg G, Carlsson GE. Symptoms of functional disturbances of the masticating system. A comparison of frequencies in a population sample and in a group of patients. Acta Odontol Scand 1975;33:183-90. Magnusson T, Egermark-Eriksson I, Carlsson GE. 5-year longitudinal study of signs and symptoms of mandibular dysfunction in adolescents. J Craniomandib Pract 1986;4:339-43.
40
Hirata et al.
Am. J. Orthod. Dentofac. Orthop. January 1992
38. Gross A, Gale EN. Longitudinalstudy of clinical signs of mandibular dysfunction.AADR Abstracts 1983;168:188. 39. Runge ME, Sadowsky C, Sakols El, BeGold EA. The relationship betweentemporomandibularsounds and malocclusion.A.',t J ORTHODDENTOFACORTIIOP1989;96:36-42. 40. SadowskyC, TheisenTA, Sakols El. Orthodontictreatmentand temporomandibularjoint sounds. A longitudinal study. AM J ORTIIODDENTOFACORTHOP1991;99:441-7. 41. Dibbets JMH, van der Weele LTh. Orthodontic treatment in relation to symptoms attributed to dysfunctionof the temporomandibularjoint. AM J ORTtlODDEmOFACOR'I'HOP1987;91: 193-9. 42. DibbetsJMH, van der Weele LTh. Extraction,orthodontictreat-
ment, and craniomandibulardysfunction. AM J ORTHODDENTOFACORVHOr'1991;99:210-9. 43. van der Weele LTh, Dibbets JMH. Conceptualmodels for analyzing symptoms of temporomandibular joint dysfunction. J CraniomandibPract 1986;4:358-66.
Reprint requests to:
Dr. Gregory J. King Department of Orthodontics Universityof Florida School of Dentistry JHMHC, Box J-444 Gainesville,FL 32610
BOUND VOLUMES AVAILABLE TO SUBSCRIBERS
Bound volumes of the AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS are available to subscribers (only) for the 1992 issues from the Publisher, at a cost of $53.00 ($67.71 Canada and $64.00 international) for Vol. 101 (January-June) and Vol. 102 (July-December). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. P a y m e n t m u s t a c c o m p a n y a l l o r d e r s . Contact M o s b y - Y e a r Book, Inc., Subscription Services, 11830 Westline Industrial Drive, St. Louis, MO 63146-3318, USA; telephone (314)453-4351 or (800)325-4177.
Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular Journal subscription.