Orthodontic treatment and temporomandibular joint disorders Jill K. Rendell, BS,* Louis A. Norton, DMD,** and Thomas Gay, PhD*** Farmington, Contr. The overall objective of this project was to study the relationship between orthodontic treatment and temporomandibular joint (TMJ) disorders. This relationship has been and remains an important and complex issue in orthodontics. The objectives of the study were to determine the incidence of TMJ pain and dysfunction in a group of orthodontic patients who were symptom-free on entering treatment, and to assess and characterize the level of pain and dysfunction in patients with symptoms, and track changes in these parameters during the course of orthodontic treatment. Standardized functional indices and physical measurements were used to describe and assess TMJ pain and dysfunction. The results of this study showed that of 451 patients without symptoms undergoing treatment at our university clinic during the 18-month project, no patient developed signs and symptoms of TMJ disorders during that time. In addition, for the 11 patients who presented with signs and symptoms of TMJ disorders at the time of their entry into the treatment program, no clear or consistent changes in levels of pain and dysfunction occurred longitudinally during the treatment period followed in this study. On the basis of these findings, a relationship between either the onset of TMJ pain and dysfunction and the course of orthodontic treatment or the change in TMJ pain and dysfunction and the course of orthodontic treatment could not be established in this particular patient population. (AMJ ORTHODDENTOFACORTHOP1992;101:84-7.)
T h e relationship between orthodontic treatment and temporomandibular joint (TMJ) disorders is currently an important issue in orthodontics and one that is characterized by conflicting viewpoints concerning the question of whether orthodontic treatment can either resolve, induce, or have little or no effect on TMJ pain and dysfunction, v " Most of the previous attempts at relating TMJ pain and dysfunction to orthodontic treatment have been based on either anecdotal evidence or retrospective studies, approaches that cannot demonstrate a cause-and-effect relationship between treatment and disease. An alternative approach to this problem is to study a group of patients prospectively during the course of orthodontic treatment. Prospective longitudinal studies provide new types of information, and also represent the best method for elucidating any underlying cause-and-effect relationship between orthodontic treatment and TMJ disorders.
From the School of Dental Medicine, University of Connecticut Health Center. This research was supported in part by grants from the American Association of Orthodontists (AAO89015) and the University of Connecticut Research Foundation. *Research Associate, Department of BioStructure and Function. **Professor, Department of Orthodontics. ***Professor, Department of BioStructure and Function. 811131710
84
The specific objectives of the present project were to determine the incidence of TMJ disorders that emerged during ongoing orthodontic treatment, and to assess and characterize the level of pain and dysfunction in any identified TMJ patient subgroup, and track changes in these parameters during the course of treatment. The incidence of TMJ disorders in our patient population was determined by provider surveys; the assessment and characterization of TMJ pain and dysfunction was quantitated with standardized clinical indices and physical measurements of mandibular functioning.
EXPERIMENTAL METHODS For the purposes of this study, we defined "TMJ disorder" as a specific condition caused by any of a number of etiologic factors, whose primary symptoms were pain and dysfunction of the TMJ serious enough for the patient to seek professional help for treatment. Operationally, we characterized TMJ pain in terms of both objective clinical signs and subjective symptoms. We defined TMJ dysfunction as impaired function of the TMJ apparatus as reflected by impaired mobility of the mandible, muscle soreness, mandibular deviation, and TMJ noises.
Subjects Every patient receiving orthodontic treatment in the graduate clinical program at the University of Connecticut Health
Orthodontic treatment a n d TI~U disorders
Volume 101
Number 1
85
70 Jan
60 [~]
0
Jul.'
50 40 .,.a r~
30 C)
z
20 10 0 1985
1986
1987
1988
Enrollment
1989
1990
Period
Fig. 1. Distribution of time of enrollment for patient population.
Center was identified as having no current signs or symptoms of TMJ pain or dysfunction, or as presently complaining of TMJ pain and/or dysfunction. During the period of treatment, any patient who developed symptoms of TMJ disorders would be transferred to the disorder group. All patients, both existing and new, who were receiving treatment in the Department of Orthodontics clinic program participated in the study. During the duration of the project, a total of 462 patients were receiving treatment. Of these patients, approximately 90% were adolescents and 10% were adults over the age of 18 years. As in any large teaching clinic program, diagnoses were varied, and the distribution of patient Angle classifications were skewed, with most classified as Crass II and the fewest as Class II1. Any patient who had a complaint of facial or jaw pain either at the outset or at any time dttritlg the course of the study, underwent a formal TMJ evaluation. Each patient was questioned regarding the character, location, onset, and progression of pain, noticeable dysfunction, related complaints (e.g., headache, vertigo, tinnitus), or other symptoms. Sensitivity to palpation of the TMJ and muscles of mastication, presence of facial asymmetries, jaw restrictions, and deviations during function were noted. If the history and clinical examination suggested an abnormality of the temporomandibular apparatus or associated structures, and the attending clinician agreed, the patient was formally assigned to this category. These patients were informed that the purpose of this study was solely to monitor their levels of pain and dysfunction, and that the evaluative procedures employed would not affect their TMJ disorder. In addition, the providers made no attempt to treat the TMJ disorder except to resolve the malocclusion. Of the 462 patients in treatment during the project period, 11 met the criteria for inclusion into the TMJ subgroup. These patients ranged in age from 10 to 35 years; 10 were female;
4 were adolescents, and 7 were adults; 8 were in treatment at the outset of the study, and 3 were admitted later. Of these 11 patients, 8 had symptoms consistent with (myofascial pain dysfunction (MPD), and 3 had symptoms consistent with anterior disk displacement. None of these patients received any specific orthodontic treatment for their TMJ pain or dysfunction during the project period. During the course of the study, two patients complcted treatment, and one dropped out of the program.
Measurement of pain and dysfunction Modified versions of the Helkimo Dysfunction and Anamnestic Indices TM ,9 were used as the basis for assessing TMJ pain and dysfunction. The dysfunction index assessed five different variables: impaired range of movement, impaired function of temporomandibular joint, pain on movement, muscle soreness, and temporomandibular joint pain. The mandibular displacement measurements made during the clinical examination were also used in their raw form for making quantitative comparisons of maximum distances in actual millimeters. In addition, TMJ sounds and correlated mandibular movements were recorded instrumentally.-'° In addition to assessing clinically evident dysfunction, the patient's perception of the level of disability was also assessed with the Anamnestic Index of Helkimo. TM ~9 This index is based on the patient's report of different symptoms of dysfunction of the masticatory system. Information was elicited on the basis of a methodical interview by the clinician and completion of a questionnaire. All data for this part of the study were obtained during a period that preceded each regularly scheduled patient visit. Each patient first underwent an examination for the Helkimo dysfunction variables. The dysfunction variables for all patients and visits were assessed by the same examiner using standard clinical techniques.
86
Rendell. Norton, and Gay
Am. J. Orthod.Dentofac. Orthop. January 1992
RESULTS
A total of 462 patients were enrolled in the orthodontic graduate treatment program at the University of Connecticut Health Center during the 18-month course of this study. Of that total, 11 were identified as having preexisting TMJ disorders. During the duration of the study, none of the other 451 patients developedany signs or symptoms of TMJ disorders, and of the 8 remaining patients with symptoms in the study, none evidenced a significant change in the level of their TMJ pain or dysfunction. hwidence of TMJ pain and dysfunction. To determine the emergence of TMJ problems in the symptomfree orthodontic treatment population, faculty and residents queried patients at 4- to 6-month intervals regarding any complaints of pain and dysfunction of the TMJ. Results of the surveys indicated that no patient had any signs or symptoms of TMJ pain or dysfunction during the entire project period. These findings are based on surveys of patients who were in various stages of orthodontic treatment. Fig. 1 shows the distribution of time of patient enrollment for treatment during the course of the study. Treatment stage was fairly well distributed for this population; approximatley 27% of the patients were undergoing treatment for 1 year or less, 50% for 2 years or less, and 75% for 3 years or less. At least 50% of the patients completed the nominal 2-year period of orthodontic treatment during the study period. As can also be seen in the histogram, the majority of patients were enrolled in 1988 and 1989 and were therefore in the early stages of active treatment. Many of the patients who had been enrolled in the earlier years (1985 and 1986) were in retention and no longer in active treatment. In summary, on the basis of the information obtained from the clinical providers in the Orthodontic Clinic, it is clear that no relationship can be established between the course of orthodontic treatment and the incidence of TMJ pain and dysfunction in this clinical population. Pah7 and dysfunction in the TMJ subgroup. Of the 462 patients undergoing treatment during the study period, 11 patients presented with signs and symptoms of TMJ disorders at the time of their entrance into the treatment program. The eight remaining patients were assessed at 3-month intervals to determine changes in the levels of TMJ pain and dysfunction, and quantitative changes in mandibular mobility and joint noises. Comparisons were made variable by variable between the first visit and corresponding visits at 3-, 6-, 9-, and 12month intervals. The results of the dysfunction score analysis, for the most part, showed that there was a decrease in scores, and therefore an improvement in the condition
of the patient between the first visit and all subsequent visits. However, in some instances the scores remained the same, or even worsened slightly. None of the changes, however, was statistically significant, although considering the low N, statistical significance could not be expected. For the physical measurements, differences were also small and only approximately half of the variables showed improvement; no change, however, was statistically significant. The actual measured mandibular displacements also fell within the range clinically accepted as normal. Of the eight patients in this group, only three were identified as having detectable joint noises. However, there were no changes observed either clinically or quantitatively in the appearance of these noises in relation to mandibular displacement or in the duration or amplitude of noises from visit to visit. As with the dysfunction scores, total anamnestic scores showed slight improvement between the first and subsequent visits, none of which was statistically significant. DISCUSSION
On the basis of the findings of this study, it is clear that a relationship between the onset of TMJ pain and dysfunction and the course of orthodontic treatment could not be established in this particular patient population. These findings are consistent with other studies which have shown that orthodontic treatment, and the emergence of TMJ disorders are independent events. 9t7 More importantly, our findings disagree with the primarily anecdotal literature that suggests a negative effect of orthodontic treatment on the incidence and prevalence of TMJ problems. 4-8 In contrast to those studies, however, our results demonstrated the independence between treatment and disease for the immediate term. This has not been shown previously because most earlier studies relied on retrospective analyses of patient records and were able to draw conclusions concerning only the possible long-term effects of orthodontic treatment on the emergence of TMJ problems. It could not be determined from those studies whether treatment had an immediate short-term effect that might have been resolved later on. Thus, in demonstrating no immediate term relationship between TMJ pain and dysfunction and the orthodontic treatment, the findings of the present study might be considered complementary, as well as confirmatory, to previous ones. Another salient point concerning our patient population is that all of the patients in the study were in long-term (more than 2 years) corrective treatment. Thus, it can be speculated that any detrimental effects that treatment might have had on the joint would have become evident over the course of treatment. One of the original objectives of this study was to
Volume 107 Number 1
track changes in pain and dysfunction in patients with TMJ symptoms during the course of their orthodontic treatment. However, we were not able to adequately address that issue because the number of patients with TMJ symptoms in our clinic population was small. The low incidence of TMJ problems in our population does not suggest that orthodontic patients in general have a lower incidence of TMJ problems. Rather, patients with significant TMJ problems are usually excluded from the orthodontic treatment program at the University of Connecticut Health Center. Accordingly, the incidence of patients complaining of TMJ pain and dysfunction in our study cannot be generalized to the population as a whole because our particular patient population was specially selected. However, in those few patients who presented with TMJ problems at the time of enrollment for treatment, changes in levels of pain and/or dysfunction could not be correlated with the course of treatment. This finding agrees with previous retrospective studies that have suggested that there is no association between extensive tooth movement and the occurrence of TMJ problems, 9-17 and disagrees with previous reports that suggest that correction of malocclusions seem to ameliorate or induce TMJ problems.l8 In summary, the results of this study showed that of all TMJ symptom-free patients under treatment during the 18-month project period, no patient developed signs and symptoms of TMJ disorders during that time, and for the 11 patients who presented with signs and symptoms of TMJ disorders at the time of their entry into the treatment program, no clear or consistent changes in levels of pain and dysfunction occurred longitudinally during the treatment period. On the basis of these findings, it is clear that a relationship between either the onset of TMJ pain and dysfunction and the course of orthodontic treatment, or the change in TMJ pain and dysfunction and the orthodontic treatment could not be established in this particular patient population. REFERENCES
1. Roth RH. Temporomandibular pain-dysfunction and occlusal relationships. Angle Orthod 1973;43:136-54, 2. Riolo ML, Bran& D, TenHave TF. Associations between occlusal characteristics and signs and symptoms of TMJ dysfunction in children and young adults. A.',tJ ORTtlODDENTOFACORrHOP 1987;92:467-77. 3. Mohlin B. Prevalence of mandibular dysfunction, relation between malocclusion, mandibular dysfunction in a group of women in Sweden. Eur J Orthod 1983;13:601-2.
Orthodontic treatment and T M J disorders
87
4. Loft GH, Reynolds JM, Zwemer JD, Thompson WO, Dushku J. The occurrence of craniomandibular symptoms in healthy young adults with and without prior orthodontic treatment. Facial Orthop Temporomandibular Arthrol 1988;5:18-19. 5. Franks AST. The dental health of patients presenting with temporomandibular joint dysfunction. Br J Oral Surg 1967;5:i5766. 6. Roth RH. Temporomandibular pain-dysfunction and occlusal relationships. Angle Orthod 1973;43:136-53. 7. Berry DC, Watkinson AC. Mandibular dysfunction and incisor relationship. A theoretical explanation of the clicking joint. Br J Oral Surg 1978;44:74-7. 8. Wyatt WE. Preventing adverse effects on the temporomandibular joint through orthodontic treatment. AM J ORTHOD DENTOFAC Oa'rHo~' 1987;91:493-9. 9. Egennark-Eriksson I, Carlsson GE, Magnusson T. A long-term epidemiologic study of the relationship between occlusal factors, mandibular dysfunction in children, adolescents. J Dent Res 1987;66:67-71. 10. Sadowsky C, BeGole EA. Long-term status of temporomandibular joint function, functional occlusion after orthodontic treatment. AM J OR'trOD 1980;78:201-12. I 1. Rubin RM. A crisis in orthodontics'?.(Editorial) AM J Oa~oD DEI'CrOFACORTHOP 1987;91:508-97. 12. Rinchuse DJ. Counterpoint: preventing adverse effects on the temporomandibular joint through orthodontic treatment. AM J ORTHODDENTOFACORTHOP 1987;91:500-6. 13. Gianelly AA. Orthodontics, condylar position, and TMJ status. AM J OR'moP DEN'rOFACORTHOr' i 989;95:521-3. 14. Greene CS. Orthodontics and temporomandibular disorders. Dent Clin North Am 1988;32:529-38. 15. Sadowsky C, Poison AM. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long-term studies. AM J ORTHOD1984;86:386-90. 16. Larsson E, Ronnerman A. Mandibular dysfunction symptoms in orthodontically treated patients ten years after the completion of treatment. Eur J Orthod 1981;3:89-94, 17. Dahl BL, Krogstad BS, Ogaard B, Eckersberg T. Signs and symptoms of craniomandibular disorders in two groups of 19year-old individuals, one treated orthodontically and the other not. Acta Odontol Scand 1988;46:89-93. 18. Helkimo M, Carlsson GE, Hedegard B, Helkimo E, Lewin T. Function, dysfunction of the masticator/ system in Lapps in Northern Finland. Preliminary report of an epidemiological investigation. Svensk Tandlak Tidskr 1872;65:95-105. 19. Helkimo M. Studies on function, dysfunction of the masticatory system II. Index for anamnestic, clinical dysfunction, the occlusal state. Svensk Tandlak Tidskr 1974;67:101-21. 20. Gay T, Bertolami CN, Donoff RB, Keith DA, Kelly JP. The acoustical characteristics of the normal and abnormal temporomandibular joint. J Oral MaxilIofac Surg 1987;45:397-407. Reprint requests to:
Jill K. Rendell Department of BioStructure and Function University of Connecticut Health Center Farmington, CT 06030
T h e relationship between orthodontic treatment and temporomandibular joint (TMJ) disorders is currently an important issue in orthodontics and one that is characterized by conflicting viewpoints concerning the question of whether orthodontic treatment can either resolve, induce, or have little or no effect on TMJ pain and dysfunction, v " Most of the previous attempts at relating TMJ pain and dysfunction to orthodontic treatment have been based on either anecdotal evidence or retrospective studies, approaches that cannot demonstrate a cause-and-effect relationship between treatment and disease. An alternative approach to this problem is to study a group of patients prospectively during the course of orthodontic treatment. Prospective longitudinal studies provide new types of information, and also represent the best method for elucidating any underlying cause-and-effect relationship between orthodontic treatment and TMJ disorders.
From the School of Dental Medicine, University of Connecticut Health Center. This research was supported in part by grants from the American Association of Orthodontists (AAO89015) and the University of Connecticut Research Foundation. *Research Associate, Department of BioStructure and Function. **Professor, Department of Orthodontics. ***Professor, Department of BioStructure and Function. 811131710
84
The specific objectives of the present project were to determine the incidence of TMJ disorders that emerged during ongoing orthodontic treatment, and to assess and characterize the level of pain and dysfunction in any identified TMJ patient subgroup, and track changes in these parameters during the course of treatment. The incidence of TMJ disorders in our patient population was determined by provider surveys; the assessment and characterization of TMJ pain and dysfunction was quantitated with standardized clinical indices and physical measurements of mandibular functioning.
EXPERIMENTAL METHODS For the purposes of this study, we defined "TMJ disorder" as a specific condition caused by any of a number of etiologic factors, whose primary symptoms were pain and dysfunction of the TMJ serious enough for the patient to seek professional help for treatment. Operationally, we characterized TMJ pain in terms of both objective clinical signs and subjective symptoms. We defined TMJ dysfunction as impaired function of the TMJ apparatus as reflected by impaired mobility of the mandible, muscle soreness, mandibular deviation, and TMJ noises.
Subjects Every patient receiving orthodontic treatment in the graduate clinical program at the University of Connecticut Health
Orthodontic treatment a n d TI~U disorders
Volume 101
Number 1
85
70 Jan
60 [~]
0
Jul.'
50 40 .,.a r~
30 C)
z
20 10 0 1985
1986
1987
1988
Enrollment
1989
1990
Period
Fig. 1. Distribution of time of enrollment for patient population.
Center was identified as having no current signs or symptoms of TMJ pain or dysfunction, or as presently complaining of TMJ pain and/or dysfunction. During the period of treatment, any patient who developed symptoms of TMJ disorders would be transferred to the disorder group. All patients, both existing and new, who were receiving treatment in the Department of Orthodontics clinic program participated in the study. During the duration of the project, a total of 462 patients were receiving treatment. Of these patients, approximately 90% were adolescents and 10% were adults over the age of 18 years. As in any large teaching clinic program, diagnoses were varied, and the distribution of patient Angle classifications were skewed, with most classified as Crass II and the fewest as Class II1. Any patient who had a complaint of facial or jaw pain either at the outset or at any time dttritlg the course of the study, underwent a formal TMJ evaluation. Each patient was questioned regarding the character, location, onset, and progression of pain, noticeable dysfunction, related complaints (e.g., headache, vertigo, tinnitus), or other symptoms. Sensitivity to palpation of the TMJ and muscles of mastication, presence of facial asymmetries, jaw restrictions, and deviations during function were noted. If the history and clinical examination suggested an abnormality of the temporomandibular apparatus or associated structures, and the attending clinician agreed, the patient was formally assigned to this category. These patients were informed that the purpose of this study was solely to monitor their levels of pain and dysfunction, and that the evaluative procedures employed would not affect their TMJ disorder. In addition, the providers made no attempt to treat the TMJ disorder except to resolve the malocclusion. Of the 462 patients in treatment during the project period, 11 met the criteria for inclusion into the TMJ subgroup. These patients ranged in age from 10 to 35 years; 10 were female;
4 were adolescents, and 7 were adults; 8 were in treatment at the outset of the study, and 3 were admitted later. Of these 11 patients, 8 had symptoms consistent with (myofascial pain dysfunction (MPD), and 3 had symptoms consistent with anterior disk displacement. None of these patients received any specific orthodontic treatment for their TMJ pain or dysfunction during the project period. During the course of the study, two patients complcted treatment, and one dropped out of the program.
Measurement of pain and dysfunction Modified versions of the Helkimo Dysfunction and Anamnestic Indices TM ,9 were used as the basis for assessing TMJ pain and dysfunction. The dysfunction index assessed five different variables: impaired range of movement, impaired function of temporomandibular joint, pain on movement, muscle soreness, and temporomandibular joint pain. The mandibular displacement measurements made during the clinical examination were also used in their raw form for making quantitative comparisons of maximum distances in actual millimeters. In addition, TMJ sounds and correlated mandibular movements were recorded instrumentally.-'° In addition to assessing clinically evident dysfunction, the patient's perception of the level of disability was also assessed with the Anamnestic Index of Helkimo. TM ~9 This index is based on the patient's report of different symptoms of dysfunction of the masticatory system. Information was elicited on the basis of a methodical interview by the clinician and completion of a questionnaire. All data for this part of the study were obtained during a period that preceded each regularly scheduled patient visit. Each patient first underwent an examination for the Helkimo dysfunction variables. The dysfunction variables for all patients and visits were assessed by the same examiner using standard clinical techniques.
86
Rendell. Norton, and Gay
Am. J. Orthod.Dentofac. Orthop. January 1992
RESULTS
A total of 462 patients were enrolled in the orthodontic graduate treatment program at the University of Connecticut Health Center during the 18-month course of this study. Of that total, 11 were identified as having preexisting TMJ disorders. During the duration of the study, none of the other 451 patients developedany signs or symptoms of TMJ disorders, and of the 8 remaining patients with symptoms in the study, none evidenced a significant change in the level of their TMJ pain or dysfunction. hwidence of TMJ pain and dysfunction. To determine the emergence of TMJ problems in the symptomfree orthodontic treatment population, faculty and residents queried patients at 4- to 6-month intervals regarding any complaints of pain and dysfunction of the TMJ. Results of the surveys indicated that no patient had any signs or symptoms of TMJ pain or dysfunction during the entire project period. These findings are based on surveys of patients who were in various stages of orthodontic treatment. Fig. 1 shows the distribution of time of patient enrollment for treatment during the course of the study. Treatment stage was fairly well distributed for this population; approximatley 27% of the patients were undergoing treatment for 1 year or less, 50% for 2 years or less, and 75% for 3 years or less. At least 50% of the patients completed the nominal 2-year period of orthodontic treatment during the study period. As can also be seen in the histogram, the majority of patients were enrolled in 1988 and 1989 and were therefore in the early stages of active treatment. Many of the patients who had been enrolled in the earlier years (1985 and 1986) were in retention and no longer in active treatment. In summary, on the basis of the information obtained from the clinical providers in the Orthodontic Clinic, it is clear that no relationship can be established between the course of orthodontic treatment and the incidence of TMJ pain and dysfunction in this clinical population. Pah7 and dysfunction in the TMJ subgroup. Of the 462 patients undergoing treatment during the study period, 11 patients presented with signs and symptoms of TMJ disorders at the time of their entrance into the treatment program. The eight remaining patients were assessed at 3-month intervals to determine changes in the levels of TMJ pain and dysfunction, and quantitative changes in mandibular mobility and joint noises. Comparisons were made variable by variable between the first visit and corresponding visits at 3-, 6-, 9-, and 12month intervals. The results of the dysfunction score analysis, for the most part, showed that there was a decrease in scores, and therefore an improvement in the condition
of the patient between the first visit and all subsequent visits. However, in some instances the scores remained the same, or even worsened slightly. None of the changes, however, was statistically significant, although considering the low N, statistical significance could not be expected. For the physical measurements, differences were also small and only approximately half of the variables showed improvement; no change, however, was statistically significant. The actual measured mandibular displacements also fell within the range clinically accepted as normal. Of the eight patients in this group, only three were identified as having detectable joint noises. However, there were no changes observed either clinically or quantitatively in the appearance of these noises in relation to mandibular displacement or in the duration or amplitude of noises from visit to visit. As with the dysfunction scores, total anamnestic scores showed slight improvement between the first and subsequent visits, none of which was statistically significant. DISCUSSION
On the basis of the findings of this study, it is clear that a relationship between the onset of TMJ pain and dysfunction and the course of orthodontic treatment could not be established in this particular patient population. These findings are consistent with other studies which have shown that orthodontic treatment, and the emergence of TMJ disorders are independent events. 9t7 More importantly, our findings disagree with the primarily anecdotal literature that suggests a negative effect of orthodontic treatment on the incidence and prevalence of TMJ problems. 4-8 In contrast to those studies, however, our results demonstrated the independence between treatment and disease for the immediate term. This has not been shown previously because most earlier studies relied on retrospective analyses of patient records and were able to draw conclusions concerning only the possible long-term effects of orthodontic treatment on the emergence of TMJ problems. It could not be determined from those studies whether treatment had an immediate short-term effect that might have been resolved later on. Thus, in demonstrating no immediate term relationship between TMJ pain and dysfunction and the orthodontic treatment, the findings of the present study might be considered complementary, as well as confirmatory, to previous ones. Another salient point concerning our patient population is that all of the patients in the study were in long-term (more than 2 years) corrective treatment. Thus, it can be speculated that any detrimental effects that treatment might have had on the joint would have become evident over the course of treatment. One of the original objectives of this study was to
Volume 107 Number 1
track changes in pain and dysfunction in patients with TMJ symptoms during the course of their orthodontic treatment. However, we were not able to adequately address that issue because the number of patients with TMJ symptoms in our clinic population was small. The low incidence of TMJ problems in our population does not suggest that orthodontic patients in general have a lower incidence of TMJ problems. Rather, patients with significant TMJ problems are usually excluded from the orthodontic treatment program at the University of Connecticut Health Center. Accordingly, the incidence of patients complaining of TMJ pain and dysfunction in our study cannot be generalized to the population as a whole because our particular patient population was specially selected. However, in those few patients who presented with TMJ problems at the time of enrollment for treatment, changes in levels of pain and/or dysfunction could not be correlated with the course of treatment. This finding agrees with previous retrospective studies that have suggested that there is no association between extensive tooth movement and the occurrence of TMJ problems, 9-17 and disagrees with previous reports that suggest that correction of malocclusions seem to ameliorate or induce TMJ problems.l8 In summary, the results of this study showed that of all TMJ symptom-free patients under treatment during the 18-month project period, no patient developed signs and symptoms of TMJ disorders during that time, and for the 11 patients who presented with signs and symptoms of TMJ disorders at the time of their entry into the treatment program, no clear or consistent changes in levels of pain and dysfunction occurred longitudinally during the treatment period. On the basis of these findings, it is clear that a relationship between either the onset of TMJ pain and dysfunction and the course of orthodontic treatment, or the change in TMJ pain and dysfunction and the orthodontic treatment could not be established in this particular patient population. REFERENCES
1. Roth RH. Temporomandibular pain-dysfunction and occlusal relationships. Angle Orthod 1973;43:136-54, 2. Riolo ML, Bran& D, TenHave TF. Associations between occlusal characteristics and signs and symptoms of TMJ dysfunction in children and young adults. A.',tJ ORTtlODDENTOFACORrHOP 1987;92:467-77. 3. Mohlin B. Prevalence of mandibular dysfunction, relation between malocclusion, mandibular dysfunction in a group of women in Sweden. Eur J Orthod 1983;13:601-2.
Orthodontic treatment and T M J disorders
87
4. Loft GH, Reynolds JM, Zwemer JD, Thompson WO, Dushku J. The occurrence of craniomandibular symptoms in healthy young adults with and without prior orthodontic treatment. Facial Orthop Temporomandibular Arthrol 1988;5:18-19. 5. Franks AST. The dental health of patients presenting with temporomandibular joint dysfunction. Br J Oral Surg 1967;5:i5766. 6. Roth RH. Temporomandibular pain-dysfunction and occlusal relationships. Angle Orthod 1973;43:136-53. 7. Berry DC, Watkinson AC. Mandibular dysfunction and incisor relationship. A theoretical explanation of the clicking joint. Br J Oral Surg 1978;44:74-7. 8. Wyatt WE. Preventing adverse effects on the temporomandibular joint through orthodontic treatment. AM J ORTHOD DENTOFAC Oa'rHo~' 1987;91:493-9. 9. Egennark-Eriksson I, Carlsson GE, Magnusson T. A long-term epidemiologic study of the relationship between occlusal factors, mandibular dysfunction in children, adolescents. J Dent Res 1987;66:67-71. 10. Sadowsky C, BeGole EA. Long-term status of temporomandibular joint function, functional occlusion after orthodontic treatment. AM J OR'trOD 1980;78:201-12. I 1. Rubin RM. A crisis in orthodontics'?.(Editorial) AM J Oa~oD DEI'CrOFACORTHOP 1987;91:508-97. 12. Rinchuse DJ. Counterpoint: preventing adverse effects on the temporomandibular joint through orthodontic treatment. AM J ORTHODDENTOFACORTHOP 1987;91:500-6. 13. Gianelly AA. Orthodontics, condylar position, and TMJ status. AM J OR'moP DEN'rOFACORTHOr' i 989;95:521-3. 14. Greene CS. Orthodontics and temporomandibular disorders. Dent Clin North Am 1988;32:529-38. 15. Sadowsky C, Poison AM. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long-term studies. AM J ORTHOD1984;86:386-90. 16. Larsson E, Ronnerman A. Mandibular dysfunction symptoms in orthodontically treated patients ten years after the completion of treatment. Eur J Orthod 1981;3:89-94, 17. Dahl BL, Krogstad BS, Ogaard B, Eckersberg T. Signs and symptoms of craniomandibular disorders in two groups of 19year-old individuals, one treated orthodontically and the other not. Acta Odontol Scand 1988;46:89-93. 18. Helkimo M, Carlsson GE, Hedegard B, Helkimo E, Lewin T. Function, dysfunction of the masticator/ system in Lapps in Northern Finland. Preliminary report of an epidemiological investigation. Svensk Tandlak Tidskr 1872;65:95-105. 19. Helkimo M. Studies on function, dysfunction of the masticatory system II. Index for anamnestic, clinical dysfunction, the occlusal state. Svensk Tandlak Tidskr 1974;67:101-21. 20. Gay T, Bertolami CN, Donoff RB, Keith DA, Kelly JP. The acoustical characteristics of the normal and abnormal temporomandibular joint. J Oral MaxilIofac Surg 1987;45:397-407. Reprint requests to:
Jill K. Rendell Department of BioStructure and Function University of Connecticut Health Center Farmington, CT 06030
