- Email: [email protected]
Evaluation of disk capture with a splint repositioning appliance
Evaluation of disk capture with a splint repositioning appliance Clinical and critical assessment with MR imaging Hiroshi Kurita, DDS, PhD, a Kenji Kurashina, DDS, PhD, a Hiroo Baba, DDS, b Akiko Ohtsuka, DDS, b Akira Kotani, DDS, PhD, c and Sigvard Kopp, DDS, PhD, d Matsumoto, Japan, and Huddinge, Sweden SHINSHU UNIVERSITY AND KAROLINSKAINSTITUTET
Objective, The purpose of this study was to evaluate disk repositioning clinically and through use of magnetic resonance imaging after the insertion of a disk repositioning appliance. Study design. Seventy-four patients with 82 temporomandibular joints showing middle to late opening movement click and closing movement click near maximum intercuspation were treated with a mandibular full-coverage repositioning splint. These joints were assessed clinically and by means of magnetic resonance imaging for disk recapture. Results. According to clinical assessment, 75.6% (62/82) of the joints were treated successfully; no click was observed from the splinted mandibular position. When compared with the results of magnetic resonance imaging assessment, clinical assessment showed an accuracy rate of 91.5%, although the incidence of the false negatives was high (40%). Conclusions. The results of this study showed that about 70% of reducing displaced disks were captured with use of the disk repositioning appliance. And it was also suggested that magnetic resonance imaging is helpful to evaluate disk repositioning therapy. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;85:377-80)
Disk displacement of the temporomandibular joint (TMJ) may cause TMJ pain and dysfunction and can lead to actual progression of disorders. 1,2 Previously, many surgical or nonsurgical methods of treatment have been reported to restore a correct disk-condylar relationship. Mandibular protrusive repositioning splint therapy (often called a disk repositioning splint) is one type of treatment and to gain a "normal" diskcondyle relationship. 3,4 Many investigators point out that there is no assurance that the articular disk is recaptured by insertion of an anterior repositioning appliance. 4-1° Preparation and placement of a disk repositioning appliance is usually performed based on clinical findings. Some investigators think that it is necessary to confirm splint recapture by means of imaging modalities. However, there have been few studies that ascertained disk recapture after the application of the disk repositioning appliance using imaging modalities. 5-1° The purpose of this article is to evaluate disk recapturing just after the application of a disk repositioning aAssistant Professor, Department of Dentistry and Oral Surgery, Shinshu University School of Medicine, bResearch Associate, Department of Dentistry and Oral Surgery, Shinshu University School of Medicine, cprofessor, Department of Dentistry and Oral Surgery, Shinshu University School of Medicine. dprofessor, Department of Clinical Oral Physiology, School of Dentistry, Karolinska Institutet. Received for publication, Feb. 3, 1997; returned for revision, April 24, 1997 and Aug. 8, 1997; accepted for publication, Nov. I8, 1997. Copyright © 1998 by Mosby, Inc. 1079-2104/98/$5.00 + 0 7112187816
splint. In this study, we used the distinct inclusion criteria stated below. The disk recapturing was assessed clinically and through use of magnetic resonance imaging (MRI). The success rate of disk splint capture and the reliability of clinical assessment for disk capture are discussed.
MATERIAL A N D METHODS This study was performed at the Department of Dentistry and Oral Surgery in Shinshu University Hospital during the period from 1990 to 1995. During this time, 450 patients were referred for the treatment of temporomandibular disorders (TMDs). Mandibular full-coverage disk repositioning appliances (Fig. 1) were used for the purpose of disk recapturing in 74 patients who were clinically determined to have anterior displaced TMJ disks with reduction. These were patients who had joint clicking that occurred at both middle to late opening and late closing (near maximum cuspation) of the mandible; most of them were later proved by MRI to have displaced disk. Protrusive positioning eliminated the clicks on clinical examination. The patients had also complained of joint pain, the existence of intra-articular interference to condylar movement, or both. The patients who had no symptoms other than joint clicking and the patients who required protrusion to edge-to-edge position or further anteriorly to eliminate reciprocal clicking were not included according to the suggestion of an earlier report.11 Of the resulting 74 subjects, 55 were women and 19 were men. The mean age was 26.2 _+ 9.2 [standard deviation (SD)]
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Complete splint capture
Partial splint capture
No splint capture
Fig. 2. Schema of criteria of MRI assessment of disk capture.
Fig. 1. Mandibular full-coverage disk repositioning appliance set in position.
years, with a range of 14 to 56 years. Ten patients had joint clicking on both sides, and thus 84 joints were assessed. The subjective experience of reciprocal clicking was noted for less than 2 years in 48 of 84 joints with an average of 34.3 ___42.2 (SD) months. Splints were constructed as an office procedure. The splint positioned the mandible anteriorly far enough to eliminate the reciprocal clicking on mouth opening. The disk was then thought to be captured by the splint. The patients were instructed to open fully, beyond the opening click, and then close in a protrusive position. The mandible was then retruded to a position just before the late click would happen. This "splinted position" was obtained by a minimum of opening and protrusive movement. The patients were instructed to wear the appliance continuously for 2 months. The patients were allowed to discontinue only when brushing their teeth and during meals if necessary. One or 2 weeks after the disk repositioning appliance was inserted, each joint was reevaluated clinically. In case the condyle translated beyond the articular eminence and the joint had no clicking from the splinted position, splint capture was judged to be successful. In those cases when the joint occasionally (one or two times per day) had clicking, (e.g., on awaking in the morning), splint capture was judged to be nearly successful. When the joint had persistent clicking or the condyle did not translate under the articular eminence, splint capture was judged to be unsuccessful. The subjects also had MRI assessment of the TMJ within a period of a few weeks after initiation of the splint therapy. MRI was performed with a 1.5-tesla system (General Electric Medical Systems, Milwaukee, Wisc.) with a TMJ surface coil (6.0 cm in diameter). At first, the TMJ was scanned without insertion of the disk repositioning appliance for the purpose of confirming the presence of a displaced disk. An initial axial local-
izer was performed with a repetition time (TR) of 300 msec, an echo time (TE) 16 msec, a field of view of 24 cm, a slice thickness of 5 mm, and a 256 x 192 scanning matrix. Five orthogonal sagittal images of TMJ with a 3-mm image slice thickness were obtained with the jaw in the intercuspal position and then at the maximal opened position. Then, the appliance was placed on the mandibular teeth after the patient opened his or her mouth fully, beyond the opening click. An axial localizer was performed again, and five corrected sagittal images again with a 3-ram image slice thickness were obtained with the jaw in the splinted position and in maximal opened position. Scanning parameters for these sagittal images were TR 500 msec, TE 15 msec, field of view of 24 cm, and a 256 x 192 scanning matrix. The MRI was assessed by a trained radiologist and one of the authors separately. If their assessments were different, they were discussed until consensus was reached. Both were blinded as to the result of clinical assessment. Disk capture was defined as the intermediate zone of the disk being located between the articular surface of the condyle and the anterior wall of the articular fossa. When the anteriorly displaced disk was corrected by the splint and the posterior band of the disk was clearly defined at the superior position relative to the condyle, the disk capture was designated to be complete. In the cases in which the anteriorly displaced disk was corrected by the splint but the posterior band of the disk was somewhat anterior to the superior position relative to the condyle, the disk capture was designated partial. In the cases where the anteriorly displaced disk was not captured by the splint, no splint capture was reported (Fig. 2).
RESULTS The results of clinical assessment of splint capture were as follows. Two patients (two joints) complained of the appliance giving discomfort and stopped the treatment within a week. Of the 82 joints examined, clinical examination revealed that splint capture was successful in 45 (54.9%) of these joints. In 17 (20.7%) of these joints, the splint capture was thought to be
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Table I. Comparison of the result of clinical versus MRI assessment of splint capture Results of clinical assessment (no. of joints)
Results of MRI assessment Complete or partial capture
No capture
Not scanned
40
2
20
2
3
15
Successful or nearly successful Unsuccessful False positive, 2 of 42 or 4.7%. False negative, 2 of 5 or 40%. Accuracy, 43 of 47 or 91.5%.
nearly successful. In the remaining 20 (24.4%) joints, the splint capture was thought to be unsuccessful according to our clinical criteria. Because 16 patients did not consent to MRI study or discontinued their visits, 41 patients with 47 joints were available for the MRI assessment. By MRI, an anteriorly displaced disk was confirmed in all joints without insertion of the appliance (Fig. 3, A and B). According to the MRI assessment, 35 (74.5%) of the 47 splinted joints were found to have complete disk recapture by the splint (Fig. 3, C and D). Seven (14.9%) joints were found to have partially captured disks. In the remaining 5 (10.6%)joints, the disk was not captured at all. The results of clinical assessment were compared with the results of MRI assessment (Table I). Of 42 joints that were judged as successfully or nearly successfully recaptured by the clinical assessment, 40 joints had their displaced disks recaptured by the splint and two joints did not. Of five joints that were clinically judged as unsuccessful, the disk was not captured in three joints and was captured in two joints. With respect to a splint capture, clinical assessment showed an accuracy rate of 91.5% (MRI and clinical examination showed agreement in 91.5% of the joints), two false positives (4.8%, 2 of 42) and two false negatives (40%, 2 of 5).
DISCUSSION The results of this study indicated that about 70% of the anteriorly displaced disks were captured by the splint, because 75.6% (62 of 82 joints) were judged as successful or nearly successful in the clinical assessment, and because our clinical assessment of disk capture showed an accuracy rate of 91.5% when compared with the results of the assessment with MRI. Unfortunately, we cannot compare this rate with those of previous studies, because there have been no such studies to the best of our knowledge. The patients did not have a pretreatment MRI study and the possibility exists that we overdiagnosed or
Fig. 3. MRIs of patient with or without disk repositionmg appliance revealed that occasionally displaced disk was successfully captured by insertion of appliance. A, Mouth closing without appliance. B, Mouth opening without appliance. C, Mouth closing with appliance. D, Mouth opening with appliance.
underdiagnosed internal derangement before treatment. However, the main aim of the study was to compare the position of the disk with and without the splint as assessed by MRI and clinical examination and thereby estimate the ability of the splint to reduce disk displacement. The joints were therefore scanned without the appliance in position and with the appliance set in position. This consecutive study showed that anteriorly displaced disks were captured with the insertion of the appliance. In this study, of 42 joints that were judged as successfully or nearly successfully treated by the clinical assessment, 40 (95.2%) joints were also successfully recaptured disk according to MRI assessment. This rate is much higher than that of previous reports. Manzione et al., 8 using arthrographic examination, found that disk capture by the splint was unsuccessful in 26 (46.4%) of 56 patients who were splinted in a position clinically thought to reduce an anterior displacement of the TMJ disk. Manco and Messing, 6 using direct sagittal computed tomography, also found that in 41.8% of joints, anterior displacement still existed with the disk reposi-
380
Kurita et al.
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY
April 1998 tioning. However, these previous reports included patients who were referred from several dental practitioners of various institutes and did not describe indications and methods for construction of the splint. In addition, there was no information about the criteria used for inclusion or exclusion of patients or the clinical criteria for successful splint capture. In this study, the subjects were chosen at our hospital on the basis of a definitive inclusion criteria and j u d g e d according to our distinct clinical criteria for disk capture. We think the inclusion and exclusion criteria may be the factors most responsible for the high positive predictive ability of the clinical assessment. The results of this study showed a high incidence of false negatives as j u d g e d by clinical examination. Because m a n y cases that were clinically j u d g e d as unsuccessful in splint capture unfortunately did not participate in the M R I study, we could not obtain a reliable rate of false negative results. In the two false-negative joints, although joint clicking remained with the splint, the MR[ study revealed the disk was captured by the splint. On the other hand, it is also reported that elimination of joint clicking or limitation of condylar translation m a y not necessarily mean that the disk is successfully captured over the head of the condyle. The disk displaced to that extent would not create clicking and interfere with condylar translation any longer. 12,13 These facts suggest that disk recapture after splint treatment is not accurately judged by clinical examination alone. Therefore we think that posttreatment and (if possible) pretreatment MRIs are helpful in evaluating the result of disk recapture treatment. CONCLUSIONS F r o m the results of this study, it is concluded that about 70% of the anteriorly displaced disks that showed both middle to late opening movement click and closing m o v e m e n t click near m a x i m u m intercuspation were recaptured b y the insertion o f a disk repositioning splint. However, because there was a high incidence of false-negative treatment results, it is also suggested that M R I is necessary to evaluate this kind of disk repositioning therapy. We wish to thank the doctors in the Department of Radiology, Shinshu University School of Medicine, for their assistance in MRI study of TMJ.
REFERENCES 1. Lundh H, Westesson P-L, Kopp S. A three-year follow-up of patients with reciprocal temporomandibularjoint clicking. Oral Surg Oral Med Oral Pathol 1987;63:530-3. 2. Westesson P-L, Lundh H. Arthrographic and clinical characteristics of patients with disk displacement who progressed to closed lock during 6-month period. Oral Surg Oral Med Oral Pathol 1989;67:654-7. 3. Clark GT. The TMJ repositioning appliance: a technique for construction, insertion, and adjustment. J Craniomandib Pract 1986;4:38-46. 4. Orenstein ES. Anterior repositioning appliances when used for anterior disk displacement with reduction: a critical review. J Craniomandib Pract 1993;1l: 141-5. 5. Tallents R, Katzberg RW, Miller T, Manzione JV, Oster C. Evaluation of arthrographically assisted splint therapy in treatment of TMJ disk displacement. J Prosthet Dent 1985;53:836-8. 6. Manco LG, Messing SG. Splint therapy evaluation with direct sagittal computed tomography. Oral Surg Oral Med Oral Pathol 1986;61:5-11. 7. Miller TL, Katzberg RW, Tallents RH, Bessette RW, Hayakawa K. Temporomandibularjoint clicking with nonreducing anterior displacement of the meniscus. Radiology 1985;154:121-4. 8. Manzione JV, Tallents R, Katzberg RW, Oster C0 Miller T. Arthrographically guided splint therapy for recapturing the temporomandibularjoint meniscus. Oral Surg Oral Med Oral Pathol 1984;57:235-40. 9. Cohen SG, MacAfee KA. The use of magnetic resonance imaging to determine splint position in the management of internal derangements of the temporomandibularjoint. J Craniomandib Pract 1994;12:167-71. 10. Bauer W, Augthun M, Wehrbein H, Muller-Leisse C, Diedrich E Occlusal splint therapy in reciprocal TMJ clicking: a critical observation within a follow-up study. Fortchritte der Kieferorthopaedie 1993;54:108-18. 11. McNeill C. Craniomandibular disorders: guidelines for evaluation, diagnosis, and management. The American Academy Craniomandibular Disorders. Chicago: Quitessence; 1990. p. 1. 12. Roberts CA, Tallents RH, Katzberg RW, Sanchez-Woodworth RE, Manzione JV, Espeland MA, et al. Clinical and arthrographic evaluation of temporomandibular joint sounds. Oral Surg Oral Med Oral Pathol 1986;62:373-6. 13. Kirk WS Jr. Magnetic resonance imaging and tomographic evaluation of occlusal appliance treatment for advanced internal derangement of the temporomandibularjoint. J Oral Maxillofac Sm'g 1991;49:9-12. Reprint requests:
Hiroshi Kurita, DDS, PhD Department of Dentistry and Oral Surgery Shinshu University School of Medicine Asahi 3-1-1, Matsumoto, 390, Japan e-mail: [email protected]
Objective, The purpose of this study was to evaluate disk repositioning clinically and through use of magnetic resonance imaging after the insertion of a disk repositioning appliance. Study design. Seventy-four patients with 82 temporomandibular joints showing middle to late opening movement click and closing movement click near maximum intercuspation were treated with a mandibular full-coverage repositioning splint. These joints were assessed clinically and by means of magnetic resonance imaging for disk recapture. Results. According to clinical assessment, 75.6% (62/82) of the joints were treated successfully; no click was observed from the splinted mandibular position. When compared with the results of magnetic resonance imaging assessment, clinical assessment showed an accuracy rate of 91.5%, although the incidence of the false negatives was high (40%). Conclusions. The results of this study showed that about 70% of reducing displaced disks were captured with use of the disk repositioning appliance. And it was also suggested that magnetic resonance imaging is helpful to evaluate disk repositioning therapy. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;85:377-80)
Disk displacement of the temporomandibular joint (TMJ) may cause TMJ pain and dysfunction and can lead to actual progression of disorders. 1,2 Previously, many surgical or nonsurgical methods of treatment have been reported to restore a correct disk-condylar relationship. Mandibular protrusive repositioning splint therapy (often called a disk repositioning splint) is one type of treatment and to gain a "normal" diskcondyle relationship. 3,4 Many investigators point out that there is no assurance that the articular disk is recaptured by insertion of an anterior repositioning appliance. 4-1° Preparation and placement of a disk repositioning appliance is usually performed based on clinical findings. Some investigators think that it is necessary to confirm splint recapture by means of imaging modalities. However, there have been few studies that ascertained disk recapture after the application of the disk repositioning appliance using imaging modalities. 5-1° The purpose of this article is to evaluate disk recapturing just after the application of a disk repositioning aAssistant Professor, Department of Dentistry and Oral Surgery, Shinshu University School of Medicine, bResearch Associate, Department of Dentistry and Oral Surgery, Shinshu University School of Medicine, cprofessor, Department of Dentistry and Oral Surgery, Shinshu University School of Medicine. dprofessor, Department of Clinical Oral Physiology, School of Dentistry, Karolinska Institutet. Received for publication, Feb. 3, 1997; returned for revision, April 24, 1997 and Aug. 8, 1997; accepted for publication, Nov. I8, 1997. Copyright © 1998 by Mosby, Inc. 1079-2104/98/$5.00 + 0 7112187816
splint. In this study, we used the distinct inclusion criteria stated below. The disk recapturing was assessed clinically and through use of magnetic resonance imaging (MRI). The success rate of disk splint capture and the reliability of clinical assessment for disk capture are discussed.
MATERIAL A N D METHODS This study was performed at the Department of Dentistry and Oral Surgery in Shinshu University Hospital during the period from 1990 to 1995. During this time, 450 patients were referred for the treatment of temporomandibular disorders (TMDs). Mandibular full-coverage disk repositioning appliances (Fig. 1) were used for the purpose of disk recapturing in 74 patients who were clinically determined to have anterior displaced TMJ disks with reduction. These were patients who had joint clicking that occurred at both middle to late opening and late closing (near maximum cuspation) of the mandible; most of them were later proved by MRI to have displaced disk. Protrusive positioning eliminated the clicks on clinical examination. The patients had also complained of joint pain, the existence of intra-articular interference to condylar movement, or both. The patients who had no symptoms other than joint clicking and the patients who required protrusion to edge-to-edge position or further anteriorly to eliminate reciprocal clicking were not included according to the suggestion of an earlier report.11 Of the resulting 74 subjects, 55 were women and 19 were men. The mean age was 26.2 _+ 9.2 [standard deviation (SD)]
377
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April 1998
Complete splint capture
Partial splint capture
No splint capture
Fig. 2. Schema of criteria of MRI assessment of disk capture.
Fig. 1. Mandibular full-coverage disk repositioning appliance set in position.
years, with a range of 14 to 56 years. Ten patients had joint clicking on both sides, and thus 84 joints were assessed. The subjective experience of reciprocal clicking was noted for less than 2 years in 48 of 84 joints with an average of 34.3 ___42.2 (SD) months. Splints were constructed as an office procedure. The splint positioned the mandible anteriorly far enough to eliminate the reciprocal clicking on mouth opening. The disk was then thought to be captured by the splint. The patients were instructed to open fully, beyond the opening click, and then close in a protrusive position. The mandible was then retruded to a position just before the late click would happen. This "splinted position" was obtained by a minimum of opening and protrusive movement. The patients were instructed to wear the appliance continuously for 2 months. The patients were allowed to discontinue only when brushing their teeth and during meals if necessary. One or 2 weeks after the disk repositioning appliance was inserted, each joint was reevaluated clinically. In case the condyle translated beyond the articular eminence and the joint had no clicking from the splinted position, splint capture was judged to be successful. In those cases when the joint occasionally (one or two times per day) had clicking, (e.g., on awaking in the morning), splint capture was judged to be nearly successful. When the joint had persistent clicking or the condyle did not translate under the articular eminence, splint capture was judged to be unsuccessful. The subjects also had MRI assessment of the TMJ within a period of a few weeks after initiation of the splint therapy. MRI was performed with a 1.5-tesla system (General Electric Medical Systems, Milwaukee, Wisc.) with a TMJ surface coil (6.0 cm in diameter). At first, the TMJ was scanned without insertion of the disk repositioning appliance for the purpose of confirming the presence of a displaced disk. An initial axial local-
izer was performed with a repetition time (TR) of 300 msec, an echo time (TE) 16 msec, a field of view of 24 cm, a slice thickness of 5 mm, and a 256 x 192 scanning matrix. Five orthogonal sagittal images of TMJ with a 3-mm image slice thickness were obtained with the jaw in the intercuspal position and then at the maximal opened position. Then, the appliance was placed on the mandibular teeth after the patient opened his or her mouth fully, beyond the opening click. An axial localizer was performed again, and five corrected sagittal images again with a 3-ram image slice thickness were obtained with the jaw in the splinted position and in maximal opened position. Scanning parameters for these sagittal images were TR 500 msec, TE 15 msec, field of view of 24 cm, and a 256 x 192 scanning matrix. The MRI was assessed by a trained radiologist and one of the authors separately. If their assessments were different, they were discussed until consensus was reached. Both were blinded as to the result of clinical assessment. Disk capture was defined as the intermediate zone of the disk being located between the articular surface of the condyle and the anterior wall of the articular fossa. When the anteriorly displaced disk was corrected by the splint and the posterior band of the disk was clearly defined at the superior position relative to the condyle, the disk capture was designated to be complete. In the cases in which the anteriorly displaced disk was corrected by the splint but the posterior band of the disk was somewhat anterior to the superior position relative to the condyle, the disk capture was designated partial. In the cases where the anteriorly displaced disk was not captured by the splint, no splint capture was reported (Fig. 2).
RESULTS The results of clinical assessment of splint capture were as follows. Two patients (two joints) complained of the appliance giving discomfort and stopped the treatment within a week. Of the 82 joints examined, clinical examination revealed that splint capture was successful in 45 (54.9%) of these joints. In 17 (20.7%) of these joints, the splint capture was thought to be
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Table I. Comparison of the result of clinical versus MRI assessment of splint capture Results of clinical assessment (no. of joints)
Results of MRI assessment Complete or partial capture
No capture
Not scanned
40
2
20
2
3
15
Successful or nearly successful Unsuccessful False positive, 2 of 42 or 4.7%. False negative, 2 of 5 or 40%. Accuracy, 43 of 47 or 91.5%.
nearly successful. In the remaining 20 (24.4%) joints, the splint capture was thought to be unsuccessful according to our clinical criteria. Because 16 patients did not consent to MRI study or discontinued their visits, 41 patients with 47 joints were available for the MRI assessment. By MRI, an anteriorly displaced disk was confirmed in all joints without insertion of the appliance (Fig. 3, A and B). According to the MRI assessment, 35 (74.5%) of the 47 splinted joints were found to have complete disk recapture by the splint (Fig. 3, C and D). Seven (14.9%) joints were found to have partially captured disks. In the remaining 5 (10.6%)joints, the disk was not captured at all. The results of clinical assessment were compared with the results of MRI assessment (Table I). Of 42 joints that were judged as successfully or nearly successfully recaptured by the clinical assessment, 40 joints had their displaced disks recaptured by the splint and two joints did not. Of five joints that were clinically judged as unsuccessful, the disk was not captured in three joints and was captured in two joints. With respect to a splint capture, clinical assessment showed an accuracy rate of 91.5% (MRI and clinical examination showed agreement in 91.5% of the joints), two false positives (4.8%, 2 of 42) and two false negatives (40%, 2 of 5).
DISCUSSION The results of this study indicated that about 70% of the anteriorly displaced disks were captured by the splint, because 75.6% (62 of 82 joints) were judged as successful or nearly successful in the clinical assessment, and because our clinical assessment of disk capture showed an accuracy rate of 91.5% when compared with the results of the assessment with MRI. Unfortunately, we cannot compare this rate with those of previous studies, because there have been no such studies to the best of our knowledge. The patients did not have a pretreatment MRI study and the possibility exists that we overdiagnosed or
Fig. 3. MRIs of patient with or without disk repositionmg appliance revealed that occasionally displaced disk was successfully captured by insertion of appliance. A, Mouth closing without appliance. B, Mouth opening without appliance. C, Mouth closing with appliance. D, Mouth opening with appliance.
underdiagnosed internal derangement before treatment. However, the main aim of the study was to compare the position of the disk with and without the splint as assessed by MRI and clinical examination and thereby estimate the ability of the splint to reduce disk displacement. The joints were therefore scanned without the appliance in position and with the appliance set in position. This consecutive study showed that anteriorly displaced disks were captured with the insertion of the appliance. In this study, of 42 joints that were judged as successfully or nearly successfully treated by the clinical assessment, 40 (95.2%) joints were also successfully recaptured disk according to MRI assessment. This rate is much higher than that of previous reports. Manzione et al., 8 using arthrographic examination, found that disk capture by the splint was unsuccessful in 26 (46.4%) of 56 patients who were splinted in a position clinically thought to reduce an anterior displacement of the TMJ disk. Manco and Messing, 6 using direct sagittal computed tomography, also found that in 41.8% of joints, anterior displacement still existed with the disk reposi-
380
Kurita et al.
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY
April 1998 tioning. However, these previous reports included patients who were referred from several dental practitioners of various institutes and did not describe indications and methods for construction of the splint. In addition, there was no information about the criteria used for inclusion or exclusion of patients or the clinical criteria for successful splint capture. In this study, the subjects were chosen at our hospital on the basis of a definitive inclusion criteria and j u d g e d according to our distinct clinical criteria for disk capture. We think the inclusion and exclusion criteria may be the factors most responsible for the high positive predictive ability of the clinical assessment. The results of this study showed a high incidence of false negatives as j u d g e d by clinical examination. Because m a n y cases that were clinically j u d g e d as unsuccessful in splint capture unfortunately did not participate in the M R I study, we could not obtain a reliable rate of false negative results. In the two false-negative joints, although joint clicking remained with the splint, the MR[ study revealed the disk was captured by the splint. On the other hand, it is also reported that elimination of joint clicking or limitation of condylar translation m a y not necessarily mean that the disk is successfully captured over the head of the condyle. The disk displaced to that extent would not create clicking and interfere with condylar translation any longer. 12,13 These facts suggest that disk recapture after splint treatment is not accurately judged by clinical examination alone. Therefore we think that posttreatment and (if possible) pretreatment MRIs are helpful in evaluating the result of disk recapture treatment. CONCLUSIONS F r o m the results of this study, it is concluded that about 70% of the anteriorly displaced disks that showed both middle to late opening movement click and closing m o v e m e n t click near m a x i m u m intercuspation were recaptured b y the insertion o f a disk repositioning splint. However, because there was a high incidence of false-negative treatment results, it is also suggested that M R I is necessary to evaluate this kind of disk repositioning therapy. We wish to thank the doctors in the Department of Radiology, Shinshu University School of Medicine, for their assistance in MRI study of TMJ.
REFERENCES 1. Lundh H, Westesson P-L, Kopp S. A three-year follow-up of patients with reciprocal temporomandibularjoint clicking. Oral Surg Oral Med Oral Pathol 1987;63:530-3. 2. Westesson P-L, Lundh H. Arthrographic and clinical characteristics of patients with disk displacement who progressed to closed lock during 6-month period. Oral Surg Oral Med Oral Pathol 1989;67:654-7. 3. Clark GT. The TMJ repositioning appliance: a technique for construction, insertion, and adjustment. J Craniomandib Pract 1986;4:38-46. 4. Orenstein ES. Anterior repositioning appliances when used for anterior disk displacement with reduction: a critical review. J Craniomandib Pract 1993;1l: 141-5. 5. Tallents R, Katzberg RW, Miller T, Manzione JV, Oster C. Evaluation of arthrographically assisted splint therapy in treatment of TMJ disk displacement. J Prosthet Dent 1985;53:836-8. 6. Manco LG, Messing SG. Splint therapy evaluation with direct sagittal computed tomography. Oral Surg Oral Med Oral Pathol 1986;61:5-11. 7. Miller TL, Katzberg RW, Tallents RH, Bessette RW, Hayakawa K. Temporomandibularjoint clicking with nonreducing anterior displacement of the meniscus. Radiology 1985;154:121-4. 8. Manzione JV, Tallents R, Katzberg RW, Oster C0 Miller T. Arthrographically guided splint therapy for recapturing the temporomandibularjoint meniscus. Oral Surg Oral Med Oral Pathol 1984;57:235-40. 9. Cohen SG, MacAfee KA. The use of magnetic resonance imaging to determine splint position in the management of internal derangements of the temporomandibularjoint. J Craniomandib Pract 1994;12:167-71. 10. Bauer W, Augthun M, Wehrbein H, Muller-Leisse C, Diedrich E Occlusal splint therapy in reciprocal TMJ clicking: a critical observation within a follow-up study. Fortchritte der Kieferorthopaedie 1993;54:108-18. 11. McNeill C. Craniomandibular disorders: guidelines for evaluation, diagnosis, and management. The American Academy Craniomandibular Disorders. Chicago: Quitessence; 1990. p. 1. 12. Roberts CA, Tallents RH, Katzberg RW, Sanchez-Woodworth RE, Manzione JV, Espeland MA, et al. Clinical and arthrographic evaluation of temporomandibular joint sounds. Oral Surg Oral Med Oral Pathol 1986;62:373-6. 13. Kirk WS Jr. Magnetic resonance imaging and tomographic evaluation of occlusal appliance treatment for advanced internal derangement of the temporomandibularjoint. J Oral Maxillofac Sm'g 1991;49:9-12. Reprint requests:
Hiroshi Kurita, DDS, PhD Department of Dentistry and Oral Surgery Shinshu University School of Medicine Asahi 3-1-1, Matsumoto, 390, Japan e-mail: [email protected]