Craniomandibular disorders with special reference to orthodontic treatment: An evaluation from childhood to adulthood Inger Egermark, LDS, OD, and Birgit Thilander, LDS, OD G~teborg, Sweden The purpose of the present study was to reexamine a group of children and adolescents with respect to signs and symptoms of craniomandibular disorders (CMD) and to evaluate whether any differences could be found between persons who had received orthodontic treatment earlier and those who had not. A total of 402 children in three age groups (7, 11, and 15 years) had participated in a cross-sectional study on the relationship between malocclusion and signs and symptoms of CMD. Ten years later they were asked to answer a questionnaire. In the youngest age groups (now 17 and 21 years old) 190 (76%) subjects answered the questionnaire. In the oldest age group (now 25 years old) completed questionnaires were received from 103 (84%) subjects, and 83 (62%) of those subjects appeared for a clinical examination. Subjects with a history of orthodontic treatment had a lower prevalence of subjective symptoms of CMD (TMJ sounds included) than those without any experience of orthodontics. Although the differences were small, it was more evident for the oldest age group. The clinical examination has shown that persons who had undergone orthodontic treatment had a significantly lower clinical dysfunction index than those who had not. (AMJ ORTHOD DENTOFACORTHOP1992;101:28"34.)
A number of studies have shown a high prevalence of functional disturbances of the masticatory system in adults (for review, see Mohlin ~) although not all affected persons need treatment. Studies of the prevalence of mandibular dysfunction in children and adolescents have also shown that subjective symptoms and clinical signs of mandibular dysfunction are rather common and increase with age into adulthood. 28 However, severe and moderate signs and symptoms are not so common, and only a few need functional treatment. 9 To summarize the results from epidemiologic studies, occlusal interferences and psychologic factors seem to be more important than other variables in providing an explanation for mandibular dysfunction. Since the cause of mandibular dysfunction in children, as well as in adults, is obviously multifactorial, prevention of such disorders alone seldom warrants a decision to start orthodontic treatment. However, the correlations between mandibular dysfunction and some
From the Department of Orthodontics, Faculty of Odontology, University of G6teborg, Sweden. This study was supported by the American Association of Orthodontists (grant no. AAO 89019). 8 / 1 / 32785
28
malocclusions (such as Angle Class III, crossbite, anterior open bite, and nonworking side interferences) should be considered in the treatment planning. 2"~° A difficulty in this context is that we not only have to deal with the malocclusions present in children but also have to predict the long-term development of the occlusion. The question thus arises, is orthodontic treatment in these patients indicated or not? Furthermore, will orthodontic treatment initiate mandibular dysfunction, which has been postulated in some discussions? The most suitable age for orthodontic treatment also has to be considered in this context. It has been demonstrated that some adult patients with craniomandibular disorder (CMD) problems can be cured by occlusal adjustment "~3 or by orthodontic treatment. 14 On the other hand, the influence of orthodontic treatment on the function of the stomatognathic system is not clear. Some studies have been performed to evaluate the relationship between orthodontic treatment and mandibular dysfunction.~Sz5 From these studies it must be concluded that orthodontic treatmcnt in children and adolescents neither increases nor dec teases the risk of developing craniomandibular dysfm ction. However, only a few of these studies have repc "ted on the longterm effect of orthodontic treatment on mandibular dysfunction. Furthermore, only a few studies have dis-
Volume 101 Number 1
Orthodontic treatment and C M D
29
Examination I
11yearsi n=131~
~
n=,3S i Total n=402
Examination II
~
(onlyquestionnaire)
~ ~
~ ~
n4S [
i i 25 years
n=103 (o~57.046) n=83 clinical
of which examinations
Total n=293 Fig. 1. Age and sex distribution of 293 subjects participating in follow-up study, same subjects in examinations I and II (10 years later).
cussed the importance of occlusal factors from childhood through adolescence to adulthood. Thus the purpose of the present study was to reexamine a group of children and adolescents after an interval of 10 years with respect to signs and symptoms of CMD, and to evaluate whether any differences in these respects could be found between persons who had received orthodontic treatment earlier and those who had not.
SUBJECTS A total of 402 children in three age groups, 7, 1I, and 15 years old, had participated in a cross-sectional study on the relationship between malocclusion and signs and symptoms of craniomandibulardisorders. 2Ten years later they were asked to answer a questionnaire. Furthermore, all of the oldest age group, now 25 years old (Iz = 135), were invited to undergo a clinical examination. In the youngest age groups (now 17 and 21 years old), 17 persons had no known address or had moved from the district. Of the remainder, 190 (76%) subjects answered the questionnaire. In the oldest age group (now 25 years old), 13 persons could not be reached. Completed questionnaires were received from 103 (84%) subjects, and 83 (62%) of those subjects appeared for the clinical examination. The total number of subjects participating in the cross-sectional and longitudinal studies is shown in Fig. 1. The age and sex of the participants in the follow-up are also indicated.
METHODS Questionn= ire The participants were asked to answer a questionnaire concerning different symptoms of CMD and about orthodontic treatment. The questions on CMD symptoms (TMJ sounds, difficulties in mouth opening, and tiredness in jaws), as well as brnxism, were the same as, or only slight modifications of, those used 10 years earlier and described in detail in a previous article. ~ Some of the questions concerning earlier orthodontic treatment are shown in Table I. To check the reliability of these answers, information on corrective, as well as interceptive, orthodontic treatment was obtained from the clinical record cards of the 25-year-old subjects who had received orthodontic treatment earlier.
Clinical examination Morphologic and functional malocclusions (occlusal interferences) were recorded in the 83 subjects who had reached the age of 25. Different signs of CMD, such as mandibular mobility, TMJ function, and pain on palpation of TMJs and muscles, as well as pain on movement of the mandible, were also recorded, as described in detail in a previous study. 2 A clinical dysfunction index according to Helkimo:~ was constructed from these records. The registration of morphologic malocclusions were done according to the definitions given by Bjrrk et al. :7 The functional malocclusions in question were lateral forced bite, a great distance between RCP/ICP (retruded/intercuspat con-
30 Egermark and Thilander
am. J. Orthod. Dentofac. Orthop.
January 1992
Table I. Answers to the questionnaires from the subjects (n = 100) in the three age groups (17, 21, and 25 years old) who reported experience o f orthodontic treatment 1. What kind of orthodontic treatment have you had?
2. Did you find your orthodontic treatment inconvenient?
3. Did you use your removable appliance regularly?
4. Are you satisfied with the orthodontic result?
5. Do you think your teeth have relapsed since the orthodontictreatment?
tact position) both anteroposteriorly and vertically, as well as RCP and nonworking side interferences. Statistics Wilcoxon's matched pairs signed rank test was used for analysis of differences between two examinations. Correlations between variables were calculated by means of Spearman's rank correlation. 2s The following levels of significance have been used: *** = p < 0.00l, ** = 0.001 < p < 0.01, * = 0.01 < p < 0.05. RESULTS It was clear from the 293 questionnaires returned that 100 (34%) persons had previously had some kind of orthodontic treatment. Most of them had been treated during late mixed or early permanent dentition, but some of them even in young adulthood, and two of them were still under treatment. The responses to the questions on the orthodontic treatment are given in Table I. Removable appliances (retention plates included) had been used more often than fixed ones. Only 14 of the treated subjects found the treatment inconvenient, whereas 13 o f them had often neglected their removable appliances. Regarding the result after the orthodontic treatment, 64 subjects were satisfied, whereas 13 have reported obvious relapse (Table I). Of the total number of subjects who completed the questionnaires, I8 (6%) reported that they now wanted orthodontic treatment, whereas many (58 subjects) surprisingly answered they did not know.
Fixed appliances Removable appliances Fixed and removable appliances Don't know Yes Sometimes No Don't know Yes Sometimes neglected Often neglected Don't know Yes, very satisfied Yes, acceptable It would be better No, not at all Don't know Yes, very much Yes, little No Don't know and those in retention
5 60 34 1 14 42 40 4 55 27 13 5 35 29 22 l 13 13 26 31 30
In the 25-year-old group, 31 subjects reported that they had had orthodontic treatment, with fixed as well as with removable appliances. The clinical record cards in this age group verified this information. Of these subjects, 21 had received corrective treatment in an orthodontic clinic, whereas the other 10 subjects had received interceptive or simple corrective orthodontic treatment with only removable appliances in a general dental clinic. The prevalence of different subjective symptoms of CMD and orofacial parafunctions in a longitudinal aspect is presented for subjects with and without orthodontic treatment. As can be seen in Fig. 2, subjective symptoms and bruxism have increased in all age groups, and subjective symptoms were more pronounced in the untreated persons. The prevalence of reported TMJ sounds was somewhat higher at the follow-up examination among the subjects without earlier orthodontic treatment than in those who had been treated, although the differences were small (Table II). Of interest to note is that clicking recorded at the first examination may have disappeared 10 years later. On the other hand, "no clicking" may change into "clicking" with age, irrespective of whether orthodontic treatment was given or not. In addition to the questionnaire, different clinical signs of CMD, as well as morphologic and functional malocclusions, were recorded only in the 25-year-old group. The clinical dysfunction index was lower in those with than in those without experience of orthodontic treatment (Fig. 3). Correlation tests were made
Volume 101 Number I
Orthodontic treatment and C M D
31
% U = occasionalsymptom
I
SUBJECTIVE SYPMTOMS OF CM D
= frequent symptom
BRUXISM
oiiiii!ii!!!!!ii!iI!!!i!tililiiiiiiiii!i!iiii!i i il i
30
10
Years: 7-17 7-17 Orthodontics:
Yes
No
11-21 11-21 Yes
15-25 15-25
No
Yes
No
7-17 7-17
11-21 1t-21
Yes
Yes
No
No
15-25 15-25 Yes
No
Fig. 2. Distribution of subjective symptoms of CMD and reported orofacial parafunction (bruxism) in three different age groups at examination I (7, 11, 15 years old) and in the same subjects at examination II, 10 years later (17, 21, 25 years old). Yes = earlier orthodontic treatment (n = 95). No = no orthodontic treatment (n = 176). Reported answers "Don't know" are excluded.
Table II. Distribution of reported TMJ sounds (prevalence in brackets) at examinations I and II, as well as the changes during the 10-year follow-up period, given separately for subjects with and without earlier orthodontic treatment
Orthodontic treatment (n = 95): Examination I
TMJ sounds
(13%)
No TMJ sounds (87%) No orthodontic treatment (n = 176):
12 ~
Examination H
2
0
6
~
83
(16%)
28
No TMJ sounds
(84%)
148
(27%)
69
(73%)
Examination H
Examination I
TMJ sounds
26
(10 years later)
(10 ],,ears later)
(35%) 104
~
115
(65%)
"Don't know" answers are excluded (five in the orlhodonlic group and eight in ihe nononhodomic group).
between subejcts with and without orthodontic treatment related to subjective symptoms of CMD, orofacial parafunctions, clinical signs of CMD, as well as to morphologic and functional maloeclusions. The significant correlations were few, and the correlation coef-
ficients in general were small, except for the clinical dysfunction index, which was low for subjects Who had received orthodontic treatment earlier (Table III). A comparison was also made between those 25year-old subjects who had been treated in an orthodontic
32 Egermark and Thilander
A,,. ]. Orthod. Dentofac. Orthop.
January 1992
%
[ - ] = Di 0 CLINICAL SIGNS OF CMD [ ] = Di 1 m 70 ...................................................................................................................................................................................... M = Di. IHII .................... GO ...........................................................................................................................................................................................................................
ii
....
t \,
ii i i lI1 iiii iiiii i i i iii ii i i i i iii I i iiiiii
..........................
.....................................
,o
Years: Orthodontics:
15
25
15
25
Yes
Yes
No
No
Fig. 3. Distribution of clinical signs of CMD (dysfunction index of Helkimo, Di) at examinations I (15 years old) and II in same subjects (25 years old), given separately for subjects with (n = 31) and without (n = 52) earlier orthodontic treatment. Light fields (DiO) = no dysfunction; hatched fields (Di I) = mild dysfunction; dark fields (Di II and I11) = moderate and severe dysfunction.
clinic (n = 21) and in a general dental clinic (n = 10) for the prevalence of subjective symptoms and clinical signs of CMD (Table IV). Reported subjective symptoms of CMD, TMJ sounds, and bruxism were not so frequent in the "corrective group." Morphologic malocclusions in those subjects were also few, compared with those in the "interceptive group" and with those who had no orthodontic treatment. Furthermore, no person with dysfunction index II was recorded in the corrective group, in contrast to the other two groups. DISCUSSION The present longitudinal study has shown that persons with a history of orthodontic treatment had a lower prevalence of subjective symptoms of CMD (TMJ sounds included) than those without any experience of orthodontics. Although the differences were small, it was more evident for the oldest age group. Furthermore, the clinical examination performed in the 25-year-old group has shown that persons who had undergone orthodontic treatment had a significantly lower clinical dysfunction index than those who had not. In this follow-up study, the clinical variables, as well as the questions in the questionnaire, were the same as, or only slightly modified from, those used 10 and
5 years previously for the s a m e p e r s o n s , z,25.29 The reliability of the answers for the subjective symptoms can always be discussed, but the results of the present and earlier studies are in very close agreement. Furthermore, the clinical variables have been recorded in the same way, by the same persons, in all studies, which have already demonstrated good reproducibility for both the intraobserver and interobserver variations. 3° Furthermore, the answers in the questionnaires returned by the 25-year-old subjects were found to be in very good agreement with the information on corrective and interceptive treatment obtained from the clinical record cards. Thus it must be concluded that the results may be regarded as reliable. The subjective symptoms and bruxism increased in all age groups during the follow-up period of 10 years, and the prevalence did not differ from that found in earlier studies dealing with these problems. 46 The subjective symptoms in the present study were, however, more pronounced in subjects without earlier orthodontic treatment, than in those who had undergone treatment, especially in the oldest age group. In most subjects the orthodontic treatment had been finished at 13 to 16 years of age, which means that the 25-year-old subjects had been "out of retention" for a longer period than the
Volume I01 Number 1
Orthodontic treatment and CMD
33
Table III. Spearman's rank correlation tests between previous orthodontic treatment in the 25-year-old
subjects and different variables from the questionnaires (n = 103) and clinical examinations (n = 83) Variable
I
Need for orthodontic treatment Great distance between R C P - I C P anteroposteriorly Normal occlusion Postnormal occlusion (Angle Class II) Scissors bite (right side) Deep bite TMJ sounds (clinical) Muscle tenderness Dysfunction index
Direction
I
Correlation coefficients
Neg Neg Pos Neg Neg Neg Neg Neg Neg
- 0.22* -0.25* + 0.25* -0.33** -0.24* -0.23* -0.25* - 0.29** - 0.37"**
*p < 0 . 0 0 1 . **0.001 < p < 0 . 0 1 . ***0.01 < p < 0 . 0 5 .
Table IV. Distribution of different variables in the 25-year-old subjects with and without earlier orthodontic treatment Subject symptom Reported TMJ of CMD (often) sound (often) O r t h o d o n t i c treatment 1121 = 5 % Corrective g r o u p O r t h o d o n t i c treatment 1 / 1 0 = 10% Interceptive g r o u p N o orthodontic treatment 1 0 / 7 2 = 14%
1/21 = 5 %
Bruxism (often) 1121 = 5 %
°°1
dysfimetion
I
,oj ho,ogic
Dysfimction index Interferences >2 malocclusion
3/I5 = 20%Dii 5II5 Dill 1 / 1 0 = 10% 1 / 1 0 = 10% 3/8 = 38%Dii 1/8 Dill 2 / 8 1 1 / 7 2 = 15% 1 4 / 7 2 = 19% 2 4 / 6 0 = 4 0 % Dil 3 1 / 6 0 Dill 14160
= = = = = =
3 3 % 2 t 1 5 = 13% 0% 13% 2/8 = 25% 25% 52% 17/60 = 28% 23%
1115 = 7 % 2/8=
25%
18/60 = 30%
Corrective g r o u p , n = 21, o f w h i c h 15 in clinical e x a m i n a t i o n . lnterceptive g r o u p , n = 10, o f w h i c h 8 in clinical e x a m i n a t i o n . N o orthodontic treatment, n = 72, o f w h i c h 6 0 in clinical examination. T M J dysfunction; T M J sounds clinically a n d / o r pain or deviation ( > 2 m m ) at m o u t h o p e n i n g a n d / o r tenderness on palpation o f T M J s . D y s f u n c t i o n index o f H e l k i m o ; Di / = mild, Di H = m o d e r a t e d y s f u n c t i o n . (Di III = severe d y s f u n c t i o n did not a p p e a r a m o n g the 2 5 - y e a r old subjects).
subjects in the two younger age groups. The lower prevalence of symptoms and signs of CMD in that age group, although the material is small, is of special interest in a follow-up study. It should be observed that clickings recorded at the first examination may disappear within a 10-year interval. On the other hand, "no clicking" may change into "clicking" with age, irrespective of the use of orthodontic treatment. Thus clinical signs and symptoms may come and go and are by no means stable characteristics, as has been stated by other authors. 4.25.29.3~The presence of TMJ sounds (reported symptoms, as well as recorded clinical signs) was less frequent in the group given orthodontic treatment than in the untreated one. Although this difference was small, the same tendency has been found recently by Sadowsky et al? 8 The subjects in the corrective group had been treated in an orthodontic clinic for different malocclusions and with different techniques. Type of malocclusion (prenormal and postnormal occlusions, crossbite, anterior
open bite) and treatment procedures are important factors to pay attention to. Therefore it would have been of interest to evaluate the effect of the treatment of the particular diagnosis, but the material is too small to justify such a procedure. However, it is of interest that the subjects in this group reported fewer subjective symptoms of CMD and TMJ sounds and had fewer clinical signs of CMD than the interceptive and no treatment groups. One explanation for this difference may be the fact that a corrective treatment involves a strict treatment plan to normalize not only the occlusion but also the function. The recorded malocclusions at the follow-up examination were also few in the corrective group in contrast to the interceptive one. Many subjects in the interceptive group have reported that they had often neglected their removable appliances. Poor cooperation also seems to be an important factor to discuss in this context. In conclusion, over a 10-year period there exist only small differences between the frequency of subjective
34
Egermark and Thilander
symptoms and clinical signs of CMD in subjects with or without earlier orthodontic treatment. The fact that the clinical dysfunction index was lower in the orthodontically treated subjects than in the nontreated ones may be an indication for treatment in some cases. Because so many persons will receive orthodontic treatment today and in the future, the most significant point for the orthodontist to pay attention to is the need for thorough diagnosis and strict treatment planning. Examination of morphologic malocclusions must be completed with a functional examination of the masticatory system (interferences included) before initiation of orthodontic treatment. Such analyses must be repeated throughout the entire treatment period and preferably 5, 10, 15 years after treatment. It is hoped such welldocumented cases will give the final answer about the effect of orthodontic treatment on the function of the stomatognathic system. REFERENCES I. Mohlin B. Need and demand for orthodontic ueatment with special reference to mandibular dysfunction. A study in men and women. [Thesis} Grtcborg: University of Gfteborg; 1982. 2. Egermark-Eriksson I. Mandibular dysfunction in children and in individuals with dual bite. lThesisl Swed Dent J 1982;10 (Suppl). 3. Nilner M. Epidemiology of functional disturbances and diseases in the stomatognathic system. [Thesis] Swed Dent J 1983;17 (Suppl). 4. W,~nmanA. Craniomandibular disorders in adolescents. A longitudinal study in an urban Swedish population. [Thesisl Swed Dent J 1987;44 (Suppl). 5. Riolo ML, Brandt D, Ten Have TR. Associations between occlusal characteristics and signs and symptoms of TMJ dysfunction in children and young adults. AM J ORmOO DEN'I'OFAC OR'rHOP 1987;92:467-77. 6. Heikinheimo K, Salmi K, Mylliimiemi S, Kirveskari P. Symptoms of craniomandibular disorders in a sample of Finnish adolescent at the ages of 12 and 15 years. Eur J Orthod 1989; 11:325-3 I. 7. Mohlin B, Pilley JR, Shaw WC. A survey of craniomandibular disorders in 1000 12-year-olds. Study design and baseline data in a follow-up study. Eur J Orthod 199 i; 13:111-23. 8. Tallents RH, Catania J, Sommers E. Temporomandibular joint findings in pediatric populations and young adults: a critical review. Angle Orthod 1991;61:7-16. 9. Magnusson T, Carlsson GE, Egermark-Eriksson I. An evaluation of the need and demand for treatment of craniomandibular disorders in a young Swedish population. J Craniomandib Disord Facial Oral Pain 1991;5:57-63. 10. Mohlin B, Ingervall B, Thilander B. Relation between malocclusion and mandibular dysfunction in Swedish men. Eur J Orthod 1980;2:229-38. 11. Magnusson T, Carlsson GE. Occlusal adjustment in patients with residual or recurrent signs of mandibular dysfunction. J Prosthet Dent 1983;49:706-10. 12. Forssell H. Mandibular dysfunction and headache. [Thesis] Finn Dent Soc 1985; Suppl It. 13. Wenneberg N, Nystrrm T, Carlsson GE. Occlusal equilibration
Am. J. Orthod. Dentofac. Orthop. January 1992
14.
15.
16.
17.
18.
19.
20. 21.
22.
23.
24.
25.
26.
27. 28. 29.
30.
31.
and other stomatognathic treatment in patients with mandibular dysfunction and headache. J Prosthet Dent 1988;59:478-84. Mohlin B, Thilander B. The importance of the relationship between malocclusion and mandibular dysfunction and some clinical applications in adults. Eur J Orthod 1984;6:192-204. Sadowsky C, BeGole EA. Long-term status of temporomandibular joint function and functional occlusion after orthodontic treatment. A.~t J ORa'HOD 1980;78:201-12. Sadowsky C, Polsen AM. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long-term studies. AM J ORTHOD 1984;86:386-90. Sadowsky C, Muhl ZF, Sakols El, Sommerville JM. Temporomandibular joint sounds and orthodontic treatment. J Dent Res 1985;64: i 392-5. Sadowsky C, Theisen TA, Sakols El. Orthodontic treatment and temporomandibular joint sounds - a longitudinal study. AM J ORTItOD DENTOFACORTHOP 1991;99:441-7. Larsson E, Rrnnerman A. Mandibular dysfunction symptoms in orthodontically treated patients ten years after the completion of treatment. Eur J Orthod 1981;3:89=94. Jansson M, Hasund A. Functional problems in orthodontic patients out of retention. Eur J Orthod 1981;3:173-9. Dibbers JMH, Weele LTh van def. Orthodontic treatment in relation to symptoms attributed to dysfunction of the temporomandibular joint. AM J OR'rHOD DENTOFACORTHOP 1987;91: 193-9. Dibbets JMH, Weele LTh van def. Extraction, orthodontic treatment, and craniomandibular dysfunction. AM J ORTHODDENTOFACORTHOP 1991;99:210-9. Helm S, Kreiborg S, Solow B. Malocclusion at adolescence related to self-reported tooth loss and functional disorders in adulthood. AM J ORTHOD 1984;85:393-400. Dalai BL, Krogstad BS. Ogaard B, Eckersberg T. Signs and symptoms of craniomandibular disorders in two groups of 19year-olds, one treated orthodontically and the other not. Acta Odont Scand 1988;46:89-93. Egermark-Eriksson I, Carlsson GE, Magnusson T, Thilander B. A longitudinal study on malocclusion in relation to signs and symptoms of craniomandibular disorders in children and adolescents. Eur J Orthod 1990;12:399-407. ttelkimo M. Studies on function and dysfunction of the masticatory system. II. Index for anamnestic and clinical dysfunction and occlusal state. Swed Dent J 1974;67:101-21. Bj~rk A, Krebs AA, Solow B. A method for epidemiological registration of malocclusion. Acta Odont Scand 1964;22:27-41. Siegel S. Nonparametric statistics. New York: McGraw-Hill 1956. Magnusson T, Egermark-Eriksson 1, Carlsson GE. Five-year longitudinal study of signs and symptoms of mandibular dysfunction in adolescents. J Craniomandibular Pract 1986;4:338-44. Carlsson GE, Egermark-Eriksson I, Magnusson T. Intra- and inter-observer variation in functional examinations of the masticatory system. Swed Dent J 1980;4:i87-94. Weele LTh van der, Dibbets JMH. Conceptual models for analyzing symptoms of temporomandibular joint dysfunction. J Craniomandibular Pract 1986;4:357-66.
Reprint requests to: Dr. Inger Egermark Department of Orthodontics Box 33070 S-40033 G6teborg, Sweden
A number of studies have shown a high prevalence of functional disturbances of the masticatory system in adults (for review, see Mohlin ~) although not all affected persons need treatment. Studies of the prevalence of mandibular dysfunction in children and adolescents have also shown that subjective symptoms and clinical signs of mandibular dysfunction are rather common and increase with age into adulthood. 28 However, severe and moderate signs and symptoms are not so common, and only a few need functional treatment. 9 To summarize the results from epidemiologic studies, occlusal interferences and psychologic factors seem to be more important than other variables in providing an explanation for mandibular dysfunction. Since the cause of mandibular dysfunction in children, as well as in adults, is obviously multifactorial, prevention of such disorders alone seldom warrants a decision to start orthodontic treatment. However, the correlations between mandibular dysfunction and some
From the Department of Orthodontics, Faculty of Odontology, University of G6teborg, Sweden. This study was supported by the American Association of Orthodontists (grant no. AAO 89019). 8 / 1 / 32785
28
malocclusions (such as Angle Class III, crossbite, anterior open bite, and nonworking side interferences) should be considered in the treatment planning. 2"~° A difficulty in this context is that we not only have to deal with the malocclusions present in children but also have to predict the long-term development of the occlusion. The question thus arises, is orthodontic treatment in these patients indicated or not? Furthermore, will orthodontic treatment initiate mandibular dysfunction, which has been postulated in some discussions? The most suitable age for orthodontic treatment also has to be considered in this context. It has been demonstrated that some adult patients with craniomandibular disorder (CMD) problems can be cured by occlusal adjustment "~3 or by orthodontic treatment. 14 On the other hand, the influence of orthodontic treatment on the function of the stomatognathic system is not clear. Some studies have been performed to evaluate the relationship between orthodontic treatment and mandibular dysfunction.~Sz5 From these studies it must be concluded that orthodontic treatmcnt in children and adolescents neither increases nor dec teases the risk of developing craniomandibular dysfm ction. However, only a few of these studies have repc "ted on the longterm effect of orthodontic treatment on mandibular dysfunction. Furthermore, only a few studies have dis-
Volume 101 Number 1
Orthodontic treatment and C M D
29
Examination I
11yearsi n=131~
~
n=,3S i Total n=402
Examination II
~
(onlyquestionnaire)
~ ~
~ ~
n4S [
i i 25 years
n=103 (o~57.046) n=83 clinical
of which examinations
Total n=293 Fig. 1. Age and sex distribution of 293 subjects participating in follow-up study, same subjects in examinations I and II (10 years later).
cussed the importance of occlusal factors from childhood through adolescence to adulthood. Thus the purpose of the present study was to reexamine a group of children and adolescents after an interval of 10 years with respect to signs and symptoms of CMD, and to evaluate whether any differences in these respects could be found between persons who had received orthodontic treatment earlier and those who had not.
SUBJECTS A total of 402 children in three age groups, 7, 1I, and 15 years old, had participated in a cross-sectional study on the relationship between malocclusion and signs and symptoms of craniomandibulardisorders. 2Ten years later they were asked to answer a questionnaire. Furthermore, all of the oldest age group, now 25 years old (Iz = 135), were invited to undergo a clinical examination. In the youngest age groups (now 17 and 21 years old), 17 persons had no known address or had moved from the district. Of the remainder, 190 (76%) subjects answered the questionnaire. In the oldest age group (now 25 years old), 13 persons could not be reached. Completed questionnaires were received from 103 (84%) subjects, and 83 (62%) of those subjects appeared for the clinical examination. The total number of subjects participating in the cross-sectional and longitudinal studies is shown in Fig. 1. The age and sex of the participants in the follow-up are also indicated.
METHODS Questionn= ire The participants were asked to answer a questionnaire concerning different symptoms of CMD and about orthodontic treatment. The questions on CMD symptoms (TMJ sounds, difficulties in mouth opening, and tiredness in jaws), as well as brnxism, were the same as, or only slight modifications of, those used 10 years earlier and described in detail in a previous article. ~ Some of the questions concerning earlier orthodontic treatment are shown in Table I. To check the reliability of these answers, information on corrective, as well as interceptive, orthodontic treatment was obtained from the clinical record cards of the 25-year-old subjects who had received orthodontic treatment earlier.
Clinical examination Morphologic and functional malocclusions (occlusal interferences) were recorded in the 83 subjects who had reached the age of 25. Different signs of CMD, such as mandibular mobility, TMJ function, and pain on palpation of TMJs and muscles, as well as pain on movement of the mandible, were also recorded, as described in detail in a previous study. 2 A clinical dysfunction index according to Helkimo:~ was constructed from these records. The registration of morphologic malocclusions were done according to the definitions given by Bjrrk et al. :7 The functional malocclusions in question were lateral forced bite, a great distance between RCP/ICP (retruded/intercuspat con-
30 Egermark and Thilander
am. J. Orthod. Dentofac. Orthop.
January 1992
Table I. Answers to the questionnaires from the subjects (n = 100) in the three age groups (17, 21, and 25 years old) who reported experience o f orthodontic treatment 1. What kind of orthodontic treatment have you had?
2. Did you find your orthodontic treatment inconvenient?
3. Did you use your removable appliance regularly?
4. Are you satisfied with the orthodontic result?
5. Do you think your teeth have relapsed since the orthodontictreatment?
tact position) both anteroposteriorly and vertically, as well as RCP and nonworking side interferences. Statistics Wilcoxon's matched pairs signed rank test was used for analysis of differences between two examinations. Correlations between variables were calculated by means of Spearman's rank correlation. 2s The following levels of significance have been used: *** = p < 0.00l, ** = 0.001 < p < 0.01, * = 0.01 < p < 0.05. RESULTS It was clear from the 293 questionnaires returned that 100 (34%) persons had previously had some kind of orthodontic treatment. Most of them had been treated during late mixed or early permanent dentition, but some of them even in young adulthood, and two of them were still under treatment. The responses to the questions on the orthodontic treatment are given in Table I. Removable appliances (retention plates included) had been used more often than fixed ones. Only 14 of the treated subjects found the treatment inconvenient, whereas 13 o f them had often neglected their removable appliances. Regarding the result after the orthodontic treatment, 64 subjects were satisfied, whereas 13 have reported obvious relapse (Table I). Of the total number of subjects who completed the questionnaires, I8 (6%) reported that they now wanted orthodontic treatment, whereas many (58 subjects) surprisingly answered they did not know.
Fixed appliances Removable appliances Fixed and removable appliances Don't know Yes Sometimes No Don't know Yes Sometimes neglected Often neglected Don't know Yes, very satisfied Yes, acceptable It would be better No, not at all Don't know Yes, very much Yes, little No Don't know and those in retention
5 60 34 1 14 42 40 4 55 27 13 5 35 29 22 l 13 13 26 31 30
In the 25-year-old group, 31 subjects reported that they had had orthodontic treatment, with fixed as well as with removable appliances. The clinical record cards in this age group verified this information. Of these subjects, 21 had received corrective treatment in an orthodontic clinic, whereas the other 10 subjects had received interceptive or simple corrective orthodontic treatment with only removable appliances in a general dental clinic. The prevalence of different subjective symptoms of CMD and orofacial parafunctions in a longitudinal aspect is presented for subjects with and without orthodontic treatment. As can be seen in Fig. 2, subjective symptoms and bruxism have increased in all age groups, and subjective symptoms were more pronounced in the untreated persons. The prevalence of reported TMJ sounds was somewhat higher at the follow-up examination among the subjects without earlier orthodontic treatment than in those who had been treated, although the differences were small (Table II). Of interest to note is that clicking recorded at the first examination may have disappeared 10 years later. On the other hand, "no clicking" may change into "clicking" with age, irrespective of whether orthodontic treatment was given or not. In addition to the questionnaire, different clinical signs of CMD, as well as morphologic and functional malocclusions, were recorded only in the 25-year-old group. The clinical dysfunction index was lower in those with than in those without experience of orthodontic treatment (Fig. 3). Correlation tests were made
Volume 101 Number I
Orthodontic treatment and C M D
31
% U = occasionalsymptom
I
SUBJECTIVE SYPMTOMS OF CM D
= frequent symptom
BRUXISM
oiiiii!ii!!!!!ii!iI!!!i!tililiiiiiiiii!i!iiii!i i il i
30
10
Years: 7-17 7-17 Orthodontics:
Yes
No
11-21 11-21 Yes
15-25 15-25
No
Yes
No
7-17 7-17
11-21 1t-21
Yes
Yes
No
No
15-25 15-25 Yes
No
Fig. 2. Distribution of subjective symptoms of CMD and reported orofacial parafunction (bruxism) in three different age groups at examination I (7, 11, 15 years old) and in the same subjects at examination II, 10 years later (17, 21, 25 years old). Yes = earlier orthodontic treatment (n = 95). No = no orthodontic treatment (n = 176). Reported answers "Don't know" are excluded.
Table II. Distribution of reported TMJ sounds (prevalence in brackets) at examinations I and II, as well as the changes during the 10-year follow-up period, given separately for subjects with and without earlier orthodontic treatment
Orthodontic treatment (n = 95): Examination I
TMJ sounds
(13%)
No TMJ sounds (87%) No orthodontic treatment (n = 176):
12 ~
Examination H
2
0
6
~
83
(16%)
28
No TMJ sounds
(84%)
148
(27%)
69
(73%)
Examination H
Examination I
TMJ sounds
26
(10 years later)
(10 ],,ears later)
(35%) 104
~
115
(65%)
"Don't know" answers are excluded (five in the orlhodonlic group and eight in ihe nononhodomic group).
between subejcts with and without orthodontic treatment related to subjective symptoms of CMD, orofacial parafunctions, clinical signs of CMD, as well as to morphologic and functional maloeclusions. The significant correlations were few, and the correlation coef-
ficients in general were small, except for the clinical dysfunction index, which was low for subjects Who had received orthodontic treatment earlier (Table III). A comparison was also made between those 25year-old subjects who had been treated in an orthodontic
32 Egermark and Thilander
A,,. ]. Orthod. Dentofac. Orthop.
January 1992
%
[ - ] = Di 0 CLINICAL SIGNS OF CMD [ ] = Di 1 m 70 ...................................................................................................................................................................................... M = Di. IHII .................... GO ...........................................................................................................................................................................................................................
ii
....
t \,
ii i i lI1 iiii iiiii i i i iii ii i i i i iii I i iiiiii
..........................
.....................................
,o
Years: Orthodontics:
15
25
15
25
Yes
Yes
No
No
Fig. 3. Distribution of clinical signs of CMD (dysfunction index of Helkimo, Di) at examinations I (15 years old) and II in same subjects (25 years old), given separately for subjects with (n = 31) and without (n = 52) earlier orthodontic treatment. Light fields (DiO) = no dysfunction; hatched fields (Di I) = mild dysfunction; dark fields (Di II and I11) = moderate and severe dysfunction.
clinic (n = 21) and in a general dental clinic (n = 10) for the prevalence of subjective symptoms and clinical signs of CMD (Table IV). Reported subjective symptoms of CMD, TMJ sounds, and bruxism were not so frequent in the "corrective group." Morphologic malocclusions in those subjects were also few, compared with those in the "interceptive group" and with those who had no orthodontic treatment. Furthermore, no person with dysfunction index II was recorded in the corrective group, in contrast to the other two groups. DISCUSSION The present longitudinal study has shown that persons with a history of orthodontic treatment had a lower prevalence of subjective symptoms of CMD (TMJ sounds included) than those without any experience of orthodontics. Although the differences were small, it was more evident for the oldest age group. Furthermore, the clinical examination performed in the 25-year-old group has shown that persons who had undergone orthodontic treatment had a significantly lower clinical dysfunction index than those who had not. In this follow-up study, the clinical variables, as well as the questions in the questionnaire, were the same as, or only slightly modified from, those used 10 and
5 years previously for the s a m e p e r s o n s , z,25.29 The reliability of the answers for the subjective symptoms can always be discussed, but the results of the present and earlier studies are in very close agreement. Furthermore, the clinical variables have been recorded in the same way, by the same persons, in all studies, which have already demonstrated good reproducibility for both the intraobserver and interobserver variations. 3° Furthermore, the answers in the questionnaires returned by the 25-year-old subjects were found to be in very good agreement with the information on corrective and interceptive treatment obtained from the clinical record cards. Thus it must be concluded that the results may be regarded as reliable. The subjective symptoms and bruxism increased in all age groups during the follow-up period of 10 years, and the prevalence did not differ from that found in earlier studies dealing with these problems. 46 The subjective symptoms in the present study were, however, more pronounced in subjects without earlier orthodontic treatment, than in those who had undergone treatment, especially in the oldest age group. In most subjects the orthodontic treatment had been finished at 13 to 16 years of age, which means that the 25-year-old subjects had been "out of retention" for a longer period than the
Volume I01 Number 1
Orthodontic treatment and CMD
33
Table III. Spearman's rank correlation tests between previous orthodontic treatment in the 25-year-old
subjects and different variables from the questionnaires (n = 103) and clinical examinations (n = 83) Variable
I
Need for orthodontic treatment Great distance between R C P - I C P anteroposteriorly Normal occlusion Postnormal occlusion (Angle Class II) Scissors bite (right side) Deep bite TMJ sounds (clinical) Muscle tenderness Dysfunction index
Direction
I
Correlation coefficients
Neg Neg Pos Neg Neg Neg Neg Neg Neg
- 0.22* -0.25* + 0.25* -0.33** -0.24* -0.23* -0.25* - 0.29** - 0.37"**
*p < 0 . 0 0 1 . **0.001 < p < 0 . 0 1 . ***0.01 < p < 0 . 0 5 .
Table IV. Distribution of different variables in the 25-year-old subjects with and without earlier orthodontic treatment Subject symptom Reported TMJ of CMD (often) sound (often) O r t h o d o n t i c treatment 1121 = 5 % Corrective g r o u p O r t h o d o n t i c treatment 1 / 1 0 = 10% Interceptive g r o u p N o orthodontic treatment 1 0 / 7 2 = 14%
1/21 = 5 %
Bruxism (often) 1121 = 5 %
°°1
dysfimetion
I
,oj ho,ogic
Dysfimction index Interferences >2 malocclusion
3/I5 = 20%Dii 5II5 Dill 1 / 1 0 = 10% 1 / 1 0 = 10% 3/8 = 38%Dii 1/8 Dill 2 / 8 1 1 / 7 2 = 15% 1 4 / 7 2 = 19% 2 4 / 6 0 = 4 0 % Dil 3 1 / 6 0 Dill 14160
= = = = = =
3 3 % 2 t 1 5 = 13% 0% 13% 2/8 = 25% 25% 52% 17/60 = 28% 23%
1115 = 7 % 2/8=
25%
18/60 = 30%
Corrective g r o u p , n = 21, o f w h i c h 15 in clinical e x a m i n a t i o n . lnterceptive g r o u p , n = 10, o f w h i c h 8 in clinical e x a m i n a t i o n . N o orthodontic treatment, n = 72, o f w h i c h 6 0 in clinical examination. T M J dysfunction; T M J sounds clinically a n d / o r pain or deviation ( > 2 m m ) at m o u t h o p e n i n g a n d / o r tenderness on palpation o f T M J s . D y s f u n c t i o n index o f H e l k i m o ; Di / = mild, Di H = m o d e r a t e d y s f u n c t i o n . (Di III = severe d y s f u n c t i o n did not a p p e a r a m o n g the 2 5 - y e a r old subjects).
subjects in the two younger age groups. The lower prevalence of symptoms and signs of CMD in that age group, although the material is small, is of special interest in a follow-up study. It should be observed that clickings recorded at the first examination may disappear within a 10-year interval. On the other hand, "no clicking" may change into "clicking" with age, irrespective of the use of orthodontic treatment. Thus clinical signs and symptoms may come and go and are by no means stable characteristics, as has been stated by other authors. 4.25.29.3~The presence of TMJ sounds (reported symptoms, as well as recorded clinical signs) was less frequent in the group given orthodontic treatment than in the untreated one. Although this difference was small, the same tendency has been found recently by Sadowsky et al? 8 The subjects in the corrective group had been treated in an orthodontic clinic for different malocclusions and with different techniques. Type of malocclusion (prenormal and postnormal occlusions, crossbite, anterior
open bite) and treatment procedures are important factors to pay attention to. Therefore it would have been of interest to evaluate the effect of the treatment of the particular diagnosis, but the material is too small to justify such a procedure. However, it is of interest that the subjects in this group reported fewer subjective symptoms of CMD and TMJ sounds and had fewer clinical signs of CMD than the interceptive and no treatment groups. One explanation for this difference may be the fact that a corrective treatment involves a strict treatment plan to normalize not only the occlusion but also the function. The recorded malocclusions at the follow-up examination were also few in the corrective group in contrast to the interceptive one. Many subjects in the interceptive group have reported that they had often neglected their removable appliances. Poor cooperation also seems to be an important factor to discuss in this context. In conclusion, over a 10-year period there exist only small differences between the frequency of subjective
34
Egermark and Thilander
symptoms and clinical signs of CMD in subjects with or without earlier orthodontic treatment. The fact that the clinical dysfunction index was lower in the orthodontically treated subjects than in the nontreated ones may be an indication for treatment in some cases. Because so many persons will receive orthodontic treatment today and in the future, the most significant point for the orthodontist to pay attention to is the need for thorough diagnosis and strict treatment planning. Examination of morphologic malocclusions must be completed with a functional examination of the masticatory system (interferences included) before initiation of orthodontic treatment. Such analyses must be repeated throughout the entire treatment period and preferably 5, 10, 15 years after treatment. It is hoped such welldocumented cases will give the final answer about the effect of orthodontic treatment on the function of the stomatognathic system. REFERENCES I. Mohlin B. Need and demand for orthodontic ueatment with special reference to mandibular dysfunction. A study in men and women. [Thesis} Grtcborg: University of Gfteborg; 1982. 2. Egermark-Eriksson I. Mandibular dysfunction in children and in individuals with dual bite. lThesisl Swed Dent J 1982;10 (Suppl). 3. Nilner M. Epidemiology of functional disturbances and diseases in the stomatognathic system. [Thesis] Swed Dent J 1983;17 (Suppl). 4. W,~nmanA. Craniomandibular disorders in adolescents. A longitudinal study in an urban Swedish population. [Thesisl Swed Dent J 1987;44 (Suppl). 5. Riolo ML, Brandt D, Ten Have TR. Associations between occlusal characteristics and signs and symptoms of TMJ dysfunction in children and young adults. AM J ORmOO DEN'I'OFAC OR'rHOP 1987;92:467-77. 6. Heikinheimo K, Salmi K, Mylliimiemi S, Kirveskari P. Symptoms of craniomandibular disorders in a sample of Finnish adolescent at the ages of 12 and 15 years. Eur J Orthod 1989; 11:325-3 I. 7. Mohlin B, Pilley JR, Shaw WC. A survey of craniomandibular disorders in 1000 12-year-olds. Study design and baseline data in a follow-up study. Eur J Orthod 199 i; 13:111-23. 8. Tallents RH, Catania J, Sommers E. Temporomandibular joint findings in pediatric populations and young adults: a critical review. Angle Orthod 1991;61:7-16. 9. Magnusson T, Carlsson GE, Egermark-Eriksson I. An evaluation of the need and demand for treatment of craniomandibular disorders in a young Swedish population. J Craniomandib Disord Facial Oral Pain 1991;5:57-63. 10. Mohlin B, Ingervall B, Thilander B. Relation between malocclusion and mandibular dysfunction in Swedish men. Eur J Orthod 1980;2:229-38. 11. Magnusson T, Carlsson GE. Occlusal adjustment in patients with residual or recurrent signs of mandibular dysfunction. J Prosthet Dent 1983;49:706-10. 12. Forssell H. Mandibular dysfunction and headache. [Thesis] Finn Dent Soc 1985; Suppl It. 13. Wenneberg N, Nystrrm T, Carlsson GE. Occlusal equilibration
Am. J. Orthod. Dentofac. Orthop. January 1992
14.
15.
16.
17.
18.
19.
20. 21.
22.
23.
24.
25.
26.
27. 28. 29.
30.
31.
and other stomatognathic treatment in patients with mandibular dysfunction and headache. J Prosthet Dent 1988;59:478-84. Mohlin B, Thilander B. The importance of the relationship between malocclusion and mandibular dysfunction and some clinical applications in adults. Eur J Orthod 1984;6:192-204. Sadowsky C, BeGole EA. Long-term status of temporomandibular joint function and functional occlusion after orthodontic treatment. A.~t J ORa'HOD 1980;78:201-12. Sadowsky C, Polsen AM. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long-term studies. AM J ORTHOD 1984;86:386-90. Sadowsky C, Muhl ZF, Sakols El, Sommerville JM. Temporomandibular joint sounds and orthodontic treatment. J Dent Res 1985;64: i 392-5. Sadowsky C, Theisen TA, Sakols El. Orthodontic treatment and temporomandibular joint sounds - a longitudinal study. AM J ORTItOD DENTOFACORTHOP 1991;99:441-7. Larsson E, Rrnnerman A. Mandibular dysfunction symptoms in orthodontically treated patients ten years after the completion of treatment. Eur J Orthod 1981;3:89=94. Jansson M, Hasund A. Functional problems in orthodontic patients out of retention. Eur J Orthod 1981;3:173-9. Dibbers JMH, Weele LTh van def. Orthodontic treatment in relation to symptoms attributed to dysfunction of the temporomandibular joint. AM J OR'rHOD DENTOFACORTHOP 1987;91: 193-9. Dibbets JMH, Weele LTh van def. Extraction, orthodontic treatment, and craniomandibular dysfunction. AM J ORTHODDENTOFACORTHOP 1991;99:210-9. Helm S, Kreiborg S, Solow B. Malocclusion at adolescence related to self-reported tooth loss and functional disorders in adulthood. AM J ORTHOD 1984;85:393-400. Dalai BL, Krogstad BS. Ogaard B, Eckersberg T. Signs and symptoms of craniomandibular disorders in two groups of 19year-olds, one treated orthodontically and the other not. Acta Odont Scand 1988;46:89-93. Egermark-Eriksson I, Carlsson GE, Magnusson T, Thilander B. A longitudinal study on malocclusion in relation to signs and symptoms of craniomandibular disorders in children and adolescents. Eur J Orthod 1990;12:399-407. ttelkimo M. Studies on function and dysfunction of the masticatory system. II. Index for anamnestic and clinical dysfunction and occlusal state. Swed Dent J 1974;67:101-21. Bj~rk A, Krebs AA, Solow B. A method for epidemiological registration of malocclusion. Acta Odont Scand 1964;22:27-41. Siegel S. Nonparametric statistics. New York: McGraw-Hill 1956. Magnusson T, Egermark-Eriksson 1, Carlsson GE. Five-year longitudinal study of signs and symptoms of mandibular dysfunction in adolescents. J Craniomandibular Pract 1986;4:338-44. Carlsson GE, Egermark-Eriksson I, Magnusson T. Intra- and inter-observer variation in functional examinations of the masticatory system. Swed Dent J 1980;4:i87-94. Weele LTh van der, Dibbets JMH. Conceptual models for analyzing symptoms of temporomandibular joint dysfunction. J Craniomandibular Pract 1986;4:357-66.
Reprint requests to: Dr. Inger Egermark Department of Orthodontics Box 33070 S-40033 G6teborg, Sweden
