- Email: [email protected]
Functional and psychosocial impact related to specific temporomandibular disorder diagnoses
journal of dentistry 35 (2007) 643–650
available at www.sciencedirect.com
journal homepage: www.intl.elsevierhealth.com/journals/jden
Functional and psychosocial impact related to specific temporomandibular disorder diagnoses Daniel R. Reißmann a,*, Mike T. John a, Oliver Schierz a, Robert W. Wassell b a
Department of Prosthodontics and Materials Science, University of Leipzig, Nu¨rnberger Str. 57, 04103 Leipzig, Germany Department of Restorative Dentistry, School of Dental Sciences, Framlington Place, University of Newcastle, Newcastle upon Tyne, NE2 4BW, UK
b
article info
abstract
Article history:
Objectives: Comparing the level of impaired oral health-related quality of life (OHRQoL) in
Received 28 October 2006
patients with a specific temporomandibular disorder (TMD) diagnosis to general population
Received in revised form
subjects unaffected by TMD to derive the unique functional and psychosocial impact due to
24 April 2007
TMD.
Accepted 30 April 2007
Methods: A sample of 471 consecutive treatment seeking adult patients with at least one physical (axis I) TMD diagnosis according to the research diagnostic criteria for temporomandibular disorders (RDC/TMD) was included in this study. OHRQoL was measured using
Keywords:
the oral health impact profile (OHIP). To derive functional and psychosocial impact due to
Oral health-related quality of life
TMD mean OHIP scores were calculated from adult subjects of a regional population sample
Temporomandibular disorders
without any RDC/TMD axis I diagnosis (N = 135) from which a subgroup without any sign/
RDC/TMD
symptom according to the Helkimo-index (N = 35) was derived. These means were sub-
Oral health impact profile
tracted from mean OHIP scores of the TMD patients. Results: All TMD patients with a single axis I diagnosis presented much higher impaired OHRQoL (OHIP means: 27.5–56.2) compared to general population subjects (9.7 in subjects without any TMD sign/symptom and 14.8 in those without RDC/TMD axis I diagnosis). Group I diagnosis (myofascial pain) showed the highest OHRQoL impact with the lowest in patients with group II diagnosis (disc displacement). Patients with two pain-related diagnoses had significantly higher impaired OHRQoL than patients with a single one (58.9 versus 49.2, p = 0.03). Conclusions: All TMD axis I diagnoses have significant impact on OHRQoL. Subjects with pain-associated conditions present higher scores than those without pain. Patients with two pain-related diagnoses have more impaired OHRQoL than subjects with one diagnosis. # 2007 Elsevier Ltd. All rights reserved.
1.
Introduction
Temporomandibular disorders (TMD) are a heterogeneous group of conditions with major subtypes of myofascial pain, disc displacements, joint pain, and degenerative and inflammatory joint disease. Treatment seeking patients may present either a single or several TMD diagnoses.1–4
It is well-known that TMD patients suffer from a variety of psychosocial distress as a consequence of their condition. Furthermore, psychosocial distress is identified as a possible risk factor for TMD5 with the extent of psychosocial distress considered a major prognostic factor for treatment response.6– 8 Although it is still open for debate which psychosocial factors should be characterized, this situation renders the severity of
* Corresponding author. Tel.: +49 341 9721310; fax: +49 341 9721309. E-mail address: [email protected] (D.R. Reißmann). 0300-5712/$ – see front matter # 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jdent.2007.04.010
644
journal of dentistry 35 (2007) 643–650
psychosocial distress related to specific TMD of considerable interest. The heterogeneity of TMD disorders (pain diagnoses versus non-pain diagnoses, the presence/absence of structural changes including degenerative changes in the temporomandibular joint) suggests that there may be associated differences in patient-perceived impact. From a conceptual point of view, differences among the physical diagnoses of TMD could reflect in a second axis of diagnostic classification based on psychosocial impact. From a practical point of view, these differences may be important for clinical decisionmaking and patient-based outcome assessment. The concept oral health-related quality of life (OHRQoL) provides an opportunity to summarize a variety of possible psychosocial impacts in relation to specific oral diseases. Using OHRQoL instrument’s summary score as the measure of overall psychosocial distress would therefore allow us to characterize the overall psychosocial burden from TMD and to compare this impact among specific TMD diagnoses. It would also allow us to compare TMD with other oral diseases where OHRQoL scores are already available.9–11 By comparing the impact of a specific disease to the level of impaired oral health in the general population, one would be able to derive the psychosocial impact due to that disease (in our case to a specific TMD diagnosis)—a research goal which has so far not been targeted for oral disorders. This relative impact is important from a theoretical point of view because it would characterize the perceived burden from a specific oral disease in relation to other oral diseases found in the general population and from a therapeutic point of view because it would characterize the level of psychosocial impact potentially accessible to treatment. The aim of this study was to derive the unique functional and psychosocial impact due to TMD by comparing the level of impaired OHRQoL in patients with a RDC/TMD axis I diagnosis with general population subjects unaffected by TMD (having no specific TMD diagnosis and a subgroup with absolutely no TMD signs/symptoms).
2.
Material and methods
2.1.
Subjects, study design, and setting
TMD patients were recruited from January 2001 until July 2006 as a series of consecutive adult patients seeking treatment for masticatory muscle and TMJ problems at the Department of Prosthodontics, Martin Luther University (Halle/Salle), and the Department of Prosthodontics and Materials Science, University of Leipzig. These departments are staffed with a small group of dentists experienced with TMD management and provide primary care for both self-referred and professionally referred TMD patients. Reliability of RDC/TMD examination has been investigated in previous reports12,13 and found to be sufficient. A total of 471 patients, aged at least 14 years of age (mean age S.D.: 38.6 15.6 years, 76% women), were available who had at least one diagnosis according to the German version14 of the research diagnostic criteria for temporomandibular disorders, RDC/TMD.15 Of these patients, 293 had a single RDC/TMD axis I diagnosis, 138 had two, and 40 had three or more axis I diagnoses.
To determine the specific impact due to TMD suitable subjects for comparison were selected from a probability sample of the general population in the metropolitan area of Halle/Saale and surrounding areas, Germany (N = 163, mean age S.D.: 38.3 11.3 years, 67% women).16 These subjects were examined clinically to record all components of the RDC/ TMD and the Helkimo-index. This examination took place in 1999. The RDC/TMD examination was used to identify those subjects without a definite RDC/TMD diagnosis (N = 135; mean age S.D.: 38.5 11.5 years, 65% women). The Helkimo-index was used to identify a subgroup of these 135 subjects who had no signs or symptoms of TMD (N = 35, mean age S.D.: 36.1 10.7 years, 49% women). According to the Helkimoindex,17 TMD symptoms were defined as patient’s report of TMJ sounds, feeling of fatigue or of stiffness on awaking or on movements of the lower jaw, difficulties in opening the mouth wide, locking, jaw luxation, pain on movement of the mandible, and pain in the region of the TMJ or of the masticatory muscles. Clinical signs were defined as impaired range of movement of the mandible, impaired TMJ function, muscle pain, TMJ pain, and pain on movement of the mandible.
2.2. Functional and psychosocial TMD impact characterized by oral health-related quality of life The outcome of the study was the functional and psychosocial impact due to the specific TMD. It was conceptualized as the difference between the mean of impaired OHRQoL in patients with a specific axis I disorder minus the mean of impaired OHRQoL in general population subjects without any TMD sign/ symptom or TMD diagnosis. The influence of number of axis I diagnoses was analyzed by comparisons between patients with two or more axis I diagnoses and patients with a specific single one. The functional and psychosocial impact was conceptualized using OHRQoL. This construct was measured using OHIP-G, the German version16 of the oral health impact profile.18 The OHIP-G has 49 items derived from the English-language OHIP and four items specific for the German population. For each OHIP question, subjects were asked how frequently they had experienced the impact in the last month. Responses were made on a scale 0—never, 1—hardly ever, 2—occasionally, 3— fairly often, and 4—very often. OHRQoL impairment was characterized by the OHIP-G summary score (OHIP-G49)—the sum of all 49 item frequencies contained in the English-language OHIP (the four German-specific items were omitted to maintain international comparability). For the purpose of clarity the OHIPG49 summary score will simply be referred to as ‘OHIP score’. Reliability of OHRQoL measured by OHIP was assessed by calculating Cronbach’s alpha, which is a measure of the construct’s internal consistency (alpha: 0.95 for TMD patients and 0.96 for the general population subjects).
2.3. Diagnoses and classification of physical TMD diagnoses Patients were examined using the RDC/TMD. They consist of physical (axis I) and psychosocial (axis II) measures to assign axis I and axis II diagnoses. Since axis I diagnoses are not mutually exclusive each patient can have up to 5 out of 8
journal of dentistry 35 (2007) 643–650
Table 1 – Physical diagnoses (axis I measures) according to the research diagnostic criteria for temporomandibular disorders Main groups
Diagnoses
I: Myofascial pain
Ia: Myofascial pain without limited opening Ib: Myofascial pain with limited opening
II: Disc displacement
IIa: Disc displacement with reduction IIb: Disc displacement without reduction, with limited opening IIc: Disc displacement without reduction, without limited opening
III: Arthralgia, osteoarthritis, and osteoarthrosis
IIIa: Arthralgia IIIb: Osteoarthritis of the TMJ IIIc: Osteoarthrosis of the TMJ
possible diagnoses (Table 1), one of main group I, and two of main group II and III, one for each joint, respectively. The German version of RDC/TMD axis II is identical to the Englishlanguage original, including a graded chronic pain status (GCPS) score, a jaw disability score and measures to assess depression and somatization. The only difference compared to the English language version is that the latter two constructs (depression and somatization) are assessed according to recommendations of the working group on pain assessment of the German chapter of the international association for the study of pain.19 The ‘Allgemeine Depressionsskala’,20 the German translation of the center for epidemiological studies depression scale (CES-D),21 is used to assess depression whilst the ‘Beschwerden-Liste’22 is used to assess somatization. The reliability of the clinical examination for participating examiners was considered sufficient.12,13
2.4.
645
Statistical analyses
OHIP summary scores are presented as means and their 95% confidence intervals for TMD patients with a single diagnosis classified according to RDC/TMD axis I and for general population subjects without any TMD diagnosis and the subgroup without any TMD sign or symptom. Differences in OHIP score between subject groups were tested using t-tests. The null hypotheses for the statistical tests were: TMD has no significant effect on OHRQoL assessed with the OHIP. To interpret the differences between patients and population subjects in relation to each other, additional analyses were performed. The magnitude of the effect of each single diagnosis and main group diagnosis was calculated according to Cohen.23 The effect size (Cohen’s d) is the difference between the means of two independent groups divided by standard deviation of either group. It was calculated comparing the OHIP mean score of each single diagnosis or main group diagnosis with the mean score of subjects without any TMD sign or symptom. Due to differences in standard deviations between patients and population subjects, a pooled standard deviation was calculated for each comparison. All analyses were performed using the statistical software package STATA (Stata Statistical Software: Release 9. College Station, TX: StataCorp LP), with the probability of a type I error set at the 0.05 level.
3.
Results
3.1.
RDC/TMD axis I single diagnoses
All diagnoses presented considerable impairment to oral health-related quality of life (Fig. 1). OHIP means for diagnoses were between 27.5 and 56.2 points. This was substantially
Fig. 1 – OHRQoL in patients with single RDC/TMD clinical diagnoses in comparison with general population subjects without any diagnosis according to RDC/TMD (no Dx) and the subgroup without any sign or symptoms of TMD (Helkimo Ai0Di0 classification).
646
journal of dentistry 35 (2007) 643–650
higher than for general population subjects without any sign or symptom of TMD (OHIP score: 9.7) or general population subjects without any RDC/TMD diagnosis (OHIP score: 14.8). All diagnoses exhibited a substantial and statistically significant OHRQoL effect (Fig. 3). The diagnosis with the highest impaired OHRQoL was ‘‘myofascial pain without limited opening’’ (OHIP score: 56.2) which was about 10 points higher than patients with ‘‘myofascial pain with limited opening’’. The lowest OHRQoL level was observed for patients with ‘‘disc displacement (DD) with reduction’’ (OHIP score: 27.5). However, the level of impaired OHRQoL was still substantially higher than that in the general population. Patients with ‘‘DD without reduction with limited opening’’ had a higher impact of OHRQoL—the OHRQoL difference compared with ‘‘DD with reduction’’ was more than 15 points which was statistically significant ( p = 0.003). Statistically non-significant differences were observed for patients with ‘‘DD without reduction and without limited opening’’ compared with the other RDC/TMD group II diagnoses. Neither ‘‘arthralgia’’, ‘‘osteoarthritis’’, nor ‘‘osteoarthrosis’’ differed substantially or statistically significantly in their OHRQoL means.
3.2.
RDC/TMD main diagnostic groups
When specific diagnoses were grouped according to the three major RDC/TMD diagnostic groupings, the highest impact on OHRQoL was observed for patients with a group I (myofascial pain) diagnosis (Fig. 2). The lowest level of impaired OHRQoL was observed in patients with group II (disc displacements). The difference between group I and group II of 23.1 points was statistically significant ( p < 0.001). Patients with a group III (TMJ inflammatory and degenerative disorders) diagnosis differed statistically significantly
( p < 0.001) from patients in group II. The difference of 9 points between group I and III almost reached the level of statistical significance ( p = 0.08).
3.3. Impact of RDC/TMD axis I diagnoses and RDC/TMD main groups on OHRQoL To show the functional and psychosocial impact associated with individual TMD diagnoses, we subtracted the mean OHRQoL of the general population subjects with no sign or symptom of TMD from the scores associated with each RDC/ TMD axis I diagnosis. As can be seen from Fig. 3 each diagnosis had a considerable impact on the OHRQoL as represented by the height of the bars. None of the 95% confidence intervals included the value ‘‘0’’, i.e., all impacts were statistically significant ( p < 0.05). A similar approach was used to show the functional and psychosocial impact associated with the three main RDC/TMD diagnostic groups (Fig. 4). As expected from the previous results, every impact in comparison to the non-TMD-population was statistically significant ( p < 0.05). The effect sizes for single diagnosis ranged from 1.02 for ‘‘DD without reduction without limited opening’’ and 1.06 for ‘‘DD with reduction’’ up to 2.04 for ‘‘myofascial pain without limited opening’’ and within the three main diagnostic groups from 1.11 for group II (disc displacements) up to 1.68 for group III (TMJ inflammatory and degenerative disorders) and 1.75 for group I (myofascial pain). According to Cohen all effect sizes could be defined as large.23
3.4. Influence of number of RDC/TMD axis I diagnoses on OHRQoL For patients with a single axis I diagnosis a less impaired OHRQoL (OHIP score: 39.0) was observed than for patients with
Fig. 2 – OHRQoL in patients with single TMD diagnoses grouped according to the three main RDC/TMD groups in comparison with general population subjects without any diagnosis according to RDC/TMD (no Dx) and the subgroup without any sign or symptoms of TMD (Helkimo Ai0Di0 classification).
journal of dentistry 35 (2007) 643–650
647
Fig. 3 – OHRQoL impact associated with single RDC/TMD diagnoses. Baseline represents the mean OHIP summary score for general population subjects with no sign or symptom of TMD (Helkimo Ai0Di0 classification). two diagnoses (OHIP score: 52.9). The difference was statistically highly significant ( p < 0.001). For patients with three or more axis I diagnoses the observed OHIP score of 48.9 did not differ significantly from the OHIP score of patients with two diagnoses ( p = 0.48). Among patients with a single painrelated diagnosis (myofascial pain, arthralgia, or arthritis) an additional group II diagnosis (disc displacement) did not appear to have a further impact on OHRQoL; the OHIP score was almost the same (49.2 versus 47.1, p = 0.64). In contrast, patients with two pain-related diagnoses had significantly higher impaired OHRQoL than patients with a single one (58.9 versus 49.2, p = 0.03).
4.
Discussion
Temporomandibular disorders present a variety of psychosocial impacts. Using a standardized and widely used instrument, the oral health impact profile, we showed that specific physical TMD diagnoses have different impacts on patients.
4.1. Differences in the psychosocial impact across TMD diagnoses The psychosocial impact of TMD is related to signs and symptoms resulting in specific diagnoses. Diagnoses asso-
Fig. 4 – OHRQoL impact associated with the three main RDC/TMD groups. Baseline represents the mean OHIP summary score for general population subjects with no sign or symptom of TMD (Helkimo Ai0Di0 classification).
648
journal of dentistry 35 (2007) 643–650
ciated with pain (e.g., myofascial pain, arthralgia) have a higher impact than non-pain-related diagnoses (e.g., disc displacement with reduction). Within the TMD pain diagnoses it was observed that subjects with myogenous disorders presented more impaired oral health-related quality of life than subjects with an arthrogenous pain disorder. This was particularly obvious when effect sizes were used for characterizing the group differences. This finding is in line with Macfarlane et al.24 In TMD subjects with signs or symptoms of TMD, individuals with temporomandibular joint pain had the lowest level of disability while subjects with pain in and around the temples (myogenous pain) presented the highest proportion taking medicine for their complaints. Bush and Harkins25 reported higher pain-related limitations in activities of daily living in patients with myogenous pain than in patients with arthrogenous pain. We did not find large differences between myofascial pain with and without limited mouth opening. This is somewhat surprising because limited mandibular mobility is a core symptom and clinical sign of TMD and our findings are also in contrast to other studies. For example, Miller et al.26 found that TMD patients with a high temporomandibular opening index (i.e., increased limitation of opening) had more severe signs and symptoms of TMD than patients with a low index. Obviously, the condition myofascial pain itself has a certain impact on the individual but the limited mouth opening does not appear to add substantially to its genuine impact. The relative impact of limited opening on patients perceived OHRQoL seems to be too small to be detected with the OHIP. The OHIP questionnaire has quite a number of items related to oral functions but there are even more items describing psychological discomfort and disability/handicap. This situation may decrease the likelihood that significant differences due to the functional limitation are detected. Sample size is another important consideration when investigating group differences. Although disc displacements with reduction had the lowest OHRQoL scores they still had a substantial influence on perceived health. Although this disorder is often not associated with pain, subjects are often worried about their clicking jaw and feel uncomfortable which prompts them to seek treatment or information about their condition. This situation is reflected in an increased OHIP score. That joint sounds are associated with psychological variables has been demonstrated.27,28 In a German national survey it was reported that joint sounds affect the OHRQoL.29 ‘‘Bothering joint noises’’ were mentioned by 11% of the subjects age 16 and 79 years. In contrast, among patients with a painrelated diagnosis (myofascial pain, arthralgia, or arthritis) disc displacement seems not to add to the impact on OHRQoL. The unique impact is an important concept because for each (oral) condition the observed impairment (measured by an oral health-related quality of life instrument) has two parts. The first part is the ‘‘normal level’’ of OHRQoL in a particular population. The second part of the observed impact is due to unique impact of the conditions the patient suffers from. When presenting the unique impact of TMD diagnoses one important aspect is the comparison group. The magnitude of the unique TMD impact depends on the definition of the
comparison group without TMD diagnosis. Although general population subjects are the most plausible choice for comparison, they may have some signs and symptoms of TMD—but insufficient to warrant an RDC/TMD diagnosis. Such signs and symptoms may nevertheless influence OHRQoL—a situation observed in our study where subjects without a diagnosis had a more than 50% higher OHRQoL impact compared to subjects without any TMD sign or symptom. Due to the case definition in the RDC/TMD not all subjects with signs and symptoms of TMD can be assigned a specific TMD diagnosis. The RDC/TMD classification system is designed this way to derive a clinically meaningful characterization of the status of temporomandibular joints and masticatory muscles. Therefore, next to subjects without a RDC/TMD diagnosis, a second definition of a comparison group seemed to be worthwhile. For this approach we decided to apply the Helkimo-index.17 It provides an anamnestic and clinical dysfunction index. To receive a ‘‘0’’ for both indices, signs of TMD must not be reported by the patient and clinical symptoms of TMD must not be found in the clinical examination. This definition of not having TMD is stringent and comprehensible and thus a limited sample size resulted. However, considering the ambiguity what is regarded ‘‘free of TMD’’, the Helkimo-index derived definition seemed to be an appropriate choice to define subjects without any sign or symptom of TMD. Differences between the prevalence of signs and symptoms of TMD and the frequency of diagnoses in a particular population were observed in a previous prevalence study in our clinical TMD population.30 Although for clinical purposes a diagnosis is necessary for treatment, the results presented here support the notion that a continuum of psychosocial impairment ranging from its lowest levels in subjects without any TMD sign or symptom to probably very high levels in subjects with dysfunctional chronic TMD pain exist. The level of impaired OHRQoL could be used to characterize the severity of TMD. The magnitude of unique OHRQoL impact due to TMD is similar to the overall burden of impaired oral health-related quality of life in treatment seeking prosthodontic patients,31 institutionalized elderly,32 neurologically based facial pain patients33 and patients with burning sensations and pain in the oral mucosa with or without lesions, or skeletal malocclusion.34 These findings are in contrast with Reisine et al., who investigated the impact of different dental conditions on patients’ quality of life by using the sickness impact profile.35 In that study TMD patients presented a higher impact than those with periodontal diseases, with removable partial dentures with treatment need, or in comparison with a control group. The difference in findings may reflect variations in the tools being used or the patient populations studied.
4.2.
Methodological aspects of the study
A major strength of the study is the use of standardized and internationally widely recognized instruments, the OHIP and the RDC/TMD. Nevertheless, the limited sample size in some of the specific diagnoses is a limitation. Starting out with 471 patients, only 62% of this treatment seeking patients had a single specific diagnosis according to RDC/TMD. The
journal of dentistry 35 (2007) 643–650
co-occurrence of several diagnoses in a particular TMD patient is well-known.1–4 The low number of some specific diagnoses is also influenced by the rare occurrence of some conditions (e.g., disc displacement without reduction, arthrosis and arthritis). It is well-documented that myofascial pain, arthralgia, and disc displacement with reduction are the most frequent diagnoses in clinical samples36,37 as well as in population-based studies.38,39 In comparing the main RDC/ TMD groups the large number of patients with disc displacement with reduction among the three disc displacement diagnoses (group II) needs to be taken into account or there is a risk of underestimating the impact experienced by patients with disc displacement without reduction. In this study only the impact of physical conditions leading to a TMD diagnosis was regarded. The specific impact of conditions such as depression, somatization, and dysfunctional chronic pain was not investigated. However, it is well documented that there is a relationship between these conditions and OHRQoL,40 implying OHRQoL may be suitable to catch some of the impact of these conditions in a single measure. Summarizing the variety of psychosocial distress into one summary score has some advantages. It allows for intra and inter subject comparisons within a defined disease as well as comparing between different oral diseases. Furthermore reference values for different diseases, so called ‘norms’, can be interpreted from the scores. However, a summary score has also some disadvantages. Profiles of different psychosocial aspects in TMD patients, which might individually be important to their diagnosis and management, are lumped together in one summary score. Important information relevant for treatment planning and evaluation might therefore be lost. To overcome this disadvantage, evaluation of the oral health-related quality of life summary score could be supplemented by the assessment of OHRQoL dimensions or by reporting the presence or severity of single items. For our statistical analysis we chose parametric tests, e.g., t-tests, which require that the means are normally distributed, not the original data. The use of parametric tests for our analyses is supported by the ‘central limit theorem’ which says that means are normally distributed regardless of the shape of the original distribution when the number of subjects is not small as in our study.41 Multiple testing may occur as another methodological challenge in our study. However, we did not want to control the error rate per study. Therefore, we did not adjust our statistical tests for multiple testing, i.e., we did not reduce the alpha level. We believe that different characteristics were examined in our study and it is not desirable to control the error rate of the whole study, since this would reduce the statistical power for each characteristic. Considering all methodological pros and cons of our study, the unique impact due to TMD is an important concept and may have important clinical implications. If one assumed that before the onset of TMD patients had similar OHRQoL to the general population then the magnitude of psychosocial impairment characterized in this study may be accessible to treatment. It follows that the OHRQoL impact due to TMD might represent, on average, what would be hoped for as treatment benefit which is equally important for patient and treatment providers.
649
references
1. Yap AU, Dworkin SF, Chua EK, List T, Tan KB, Tan HH. Prevalence of temporomandibular disorder subtypes, psychologic distress, and psychosocial dysfunction in Asian patients. Journal of Orofacial Pain 2003;17:21–8. 2. List T, Dworkin SF. Comparing TMD diagnoses and clinical findings at Swedish and US TMD centers using research diagnostic criteria for temporomandibular disorders. Journal of Orofacial Pain 1996;10:240–53. 3. Manfredini D, Segu M, Bertacci A, Binotti G, Bosco M. Diagnosis of temporomandibular diaorders according to RDC/TMD axis I findigns, a multicenter Italian study. Minerva Stomatologica 2004;53:429–38. 4. Celic R, Panduric J, Dulcic N. Psychologic status in patients with temporomandibular disorders. International Journal of Prosthodontics 2006;19:28–9. 5. Huang GJ, LeResche L, Critchlow CW, Martin MD, Drangsholt MT. Risk factors for diagnostic subgroups of painful temporomandibular disorders (TMD). Journal of Dental Research 2002;81:284–8. 6. McCreary CP, Clark GT, Oakley ME, Flack V. Predicting response to treatment for temporomandibular disorders. Journal of Craniomandibular Disorders 1992;6:161–9. 7. Grossi ML, Goldberg MB, Locker D, Tenenbaum HC. Reduced neuropsychologic measures as predictors of treatment outcome in patients with temporomandibular disorders. Journal of Orofacial Pain 2001;15:329–39. 8. Epker J, Gatchel RJ. Prediction of treatment-seeking behavior in acute TMD patients: practical application in clinical settings. Journal of Orofacial Pain 2000;14:303–9. 9. Segu M, Collesano V, Lobbia S, Rezzani C. Cross-cultural validation of a short form of the oral health impact profile for temporomandibular disorders. Community Dentistry and Oral Epidemiology 2005;33:125–30. 10. McMillan AS, Leung KC, Leung WK, Wong MC, Lau CS, Mok TM. Impact of Sjo¨gren’s syndrome on oral health-related quality of life in southern Chinese. Journal of Oral Rehabilitation 2004;31:653–9. 11. Llewellyn CD, Warnakulasuriya S. The impact of stomatological disease on oral health-related quality of life. European Journal of Oral Sciences 2003;111:297–304. 12. John MT, Zwijnenburg AJ. Interobserver variability in assessment of signs of TMD. International Journal of Prosthodontics 2001;14:265–70. 13. Schmitter M, Ohlmann B, John MT, Hirsch C, Rammelsberg P. Research diagnostic criteria for temporomandibular disorders: a calibration and reliability study. Journal of Craniomandibular Practice 2005;23:212–8. 14. John MT, Hirsch C, Reiber T, Dworkin S. Translating the research diagnostic criteria for temporomandibular disorders into German: evaluation of content and process. Journal of Orofacial Pain 2006;20:43–52. 15. Dworkin SF, LeResche L. Research diagnostic criteria for temporomandibular disorders: review, criteria, examinations and specifications, critique. Journal of Craniomandibular Disorders 1992;6:301–55. 16. John MT, Patrick DL, Slade GD. The German version of the oral health impact profile—translation and psychometric properties. European Journal of Oral Sciences 2002;110:425–33. 17. Helkimo M. Studies on function and dysfunction of the masticatory system. II. Index for anamnestic and clinical dysfunction and occlusal state. Swedish Dental Journal 1974;67:101–19. 18. Slade GD, Spencer AJ. Development and evaluation of the oral health impact profile. Community Dental Health 1994;11:3–11.
650
journal of dentistry 35 (2007) 643–650
19. Kro¨ner-Herwig B, Denecke H, Glier B, Klinger R, Nilges P, Redegeld M, et al. Qualita¨tssicherung in der Therapie chronischen Schmerzes. Ergebnisse einer Arbeitsgruppe der Deutschen Gesellschaft zum Studium des Schmerzes (DGSS) zur psychologischen Diagnostik. IX. Multidimensionale Verfahren zur Erfassung schmerzrelevanter Aspekte und Empfehlungen zur Standarddiagnostik. Der Schmerz 1996;10:47–52. 20. Hautzinger M, Bailer M. Allgemeine Depressionsskala (ADS). Weinheim: Beltz; 1995. 21. Radloff L. The CES-D scale: a self-report depression scale for research in the general population. Applied Psychological Measurement 1977;1:385–401. 22. Von Zerssen D. Die Beschwerden-Liste. Weinheim: Beltz; 1976. 23. Cohen J. Statistical power analysis for the behavioral sciences. 2nd ed. Hillsdale, NJ: Lawrence Earlbaum Associates; 1988. 24. Macfarlane TV, Blinkhorn AS, Davies RM, Kincey J, Worthington HV. Oro-facial pain in the community: prevalence and associated impact. Community Dentistry and Oral Epidemiology 2002;30:52–60. 25. Bush FM, Harkins SW. Pain-related limitation in activities of daily living in patients with chronic orofacial pain: psychometric properties of a disability index. Journal of Orofacial Pain 1995;9:57–63. 26. Miller VJ, Karic VV, Myers SL. Differences in initial symptom scores between myogenous TMD patients with high and low temporomandibular opening index. Journal of Craniomandibular Practice 2006;24:25–8. 27. Spruijt RJ, Hoogstraten J. Symptom reporting in temporomandibular joint clicking: some theoretical considerations. Journal of Craniomandibular Disorders 1992;6:213–9. 28. Spruijt RJ, Wabeke KB. Psychological factors related to the prevalence of temporomandibular joint sounds. Journal of Oral Rehabilitation 1995;22:803–8. 29. John MT, LeResche L, Koepsell TD, Hujoel PP, Miglioretti DL, Micheelis W. Oral health-related quality of life in Germany. European Journal of Oral Sciences 2003;111: 483–91. 30. Gabler M, John MT, Reiber T. Die mehrdimensionale Charakterisierung einer Patientenpopulation mit
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
kraniomandibula¨ren Dysfunktionen. Deutsche Zahna¨rztliche Zeitschrift 2001;56:332–4. John MT, Szentpetery A, Slade G, Setz JM. Oral healthrelated quality of life in patients treated with fixed, removable and complete dentures 1 month and 6 to 12 month after treatment. International Journal of Prosthodontics 2004;17:503–11. Hassel AJ, Koke U, Schmitter M, Rammelsberg P. Factors associated with oral health-related quality of life in institutionalized elderly. Acta Odontologica Scandinavica 2006;64:9–15. Murray H, Locker D, Mock D, Tenenbaum HC. Pain and the quality of life in patients referred to a craniofacial pain unit. Journal of Orofacial Pain 1996;10:316–23. Larsson P, List T, Lundstrom I, Marcusson A, Ohrbach R. Reliability and validity of a Swedish version of the oral health impact profile (OHIP-S). Acta Odontologica Scandinavica 2004;62:147–52. Reisine ST, Fertig J, Weber J, Leder S. Impact of dental conditions on patients’ quality of life. Community Dentistry and Oral Epidemiology 1989;17:7–10. Kino K, Sugisaki M, Haketa T, Amemori Y, Ishikawa T, Shibuya T, et al. The comparison between pains, difficulties in function, and associating factors of patients in subtypes of temporomandibular disorders. Journal of Oral Rehabilitation 2005;32:315–25. Reiter S, Eli I, Gavish A, Winocour E. Ethnic differences in temporomandibular disorders between Jewish an Arab populations in Israel according to RDC/TMD evaluation. Journal of Orofacial Pain 2006;20:36–42. Truelove EL, Sommers EE, LeResche L, Dworkin SF, Von Korff M. Clinical diagnostic criteria for TMD. New classification permits multiple diagnoses. Journal of the American Dental Association 1992;123:47–54. Plesh O, Sinisi SE, Crawford PB, Gansky SA. Diagnoses based on the research diagnostic criteria for temporomandibular disorders in a biracial population of young woman. Journal of Orofacial Pain 2005;19:65–75. John MT, Reißmann DR, Schierz O, Wassell RW. Oral healthrelated quality of life in patients with temporomandibular disorders. Journal of Orofacial Pain 2007;21:46–54. Norman GR, Streiner DL. PDQ statistics. 2nd ed. St. Louis: Mosby; 1996.
available at www.sciencedirect.com
journal homepage: www.intl.elsevierhealth.com/journals/jden
Functional and psychosocial impact related to specific temporomandibular disorder diagnoses Daniel R. Reißmann a,*, Mike T. John a, Oliver Schierz a, Robert W. Wassell b a
Department of Prosthodontics and Materials Science, University of Leipzig, Nu¨rnberger Str. 57, 04103 Leipzig, Germany Department of Restorative Dentistry, School of Dental Sciences, Framlington Place, University of Newcastle, Newcastle upon Tyne, NE2 4BW, UK
b
article info
abstract
Article history:
Objectives: Comparing the level of impaired oral health-related quality of life (OHRQoL) in
Received 28 October 2006
patients with a specific temporomandibular disorder (TMD) diagnosis to general population
Received in revised form
subjects unaffected by TMD to derive the unique functional and psychosocial impact due to
24 April 2007
TMD.
Accepted 30 April 2007
Methods: A sample of 471 consecutive treatment seeking adult patients with at least one physical (axis I) TMD diagnosis according to the research diagnostic criteria for temporomandibular disorders (RDC/TMD) was included in this study. OHRQoL was measured using
Keywords:
the oral health impact profile (OHIP). To derive functional and psychosocial impact due to
Oral health-related quality of life
TMD mean OHIP scores were calculated from adult subjects of a regional population sample
Temporomandibular disorders
without any RDC/TMD axis I diagnosis (N = 135) from which a subgroup without any sign/
RDC/TMD
symptom according to the Helkimo-index (N = 35) was derived. These means were sub-
Oral health impact profile
tracted from mean OHIP scores of the TMD patients. Results: All TMD patients with a single axis I diagnosis presented much higher impaired OHRQoL (OHIP means: 27.5–56.2) compared to general population subjects (9.7 in subjects without any TMD sign/symptom and 14.8 in those without RDC/TMD axis I diagnosis). Group I diagnosis (myofascial pain) showed the highest OHRQoL impact with the lowest in patients with group II diagnosis (disc displacement). Patients with two pain-related diagnoses had significantly higher impaired OHRQoL than patients with a single one (58.9 versus 49.2, p = 0.03). Conclusions: All TMD axis I diagnoses have significant impact on OHRQoL. Subjects with pain-associated conditions present higher scores than those without pain. Patients with two pain-related diagnoses have more impaired OHRQoL than subjects with one diagnosis. # 2007 Elsevier Ltd. All rights reserved.
1.
Introduction
Temporomandibular disorders (TMD) are a heterogeneous group of conditions with major subtypes of myofascial pain, disc displacements, joint pain, and degenerative and inflammatory joint disease. Treatment seeking patients may present either a single or several TMD diagnoses.1–4
It is well-known that TMD patients suffer from a variety of psychosocial distress as a consequence of their condition. Furthermore, psychosocial distress is identified as a possible risk factor for TMD5 with the extent of psychosocial distress considered a major prognostic factor for treatment response.6– 8 Although it is still open for debate which psychosocial factors should be characterized, this situation renders the severity of
* Corresponding author. Tel.: +49 341 9721310; fax: +49 341 9721309. E-mail address: [email protected] (D.R. Reißmann). 0300-5712/$ – see front matter # 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jdent.2007.04.010
644
journal of dentistry 35 (2007) 643–650
psychosocial distress related to specific TMD of considerable interest. The heterogeneity of TMD disorders (pain diagnoses versus non-pain diagnoses, the presence/absence of structural changes including degenerative changes in the temporomandibular joint) suggests that there may be associated differences in patient-perceived impact. From a conceptual point of view, differences among the physical diagnoses of TMD could reflect in a second axis of diagnostic classification based on psychosocial impact. From a practical point of view, these differences may be important for clinical decisionmaking and patient-based outcome assessment. The concept oral health-related quality of life (OHRQoL) provides an opportunity to summarize a variety of possible psychosocial impacts in relation to specific oral diseases. Using OHRQoL instrument’s summary score as the measure of overall psychosocial distress would therefore allow us to characterize the overall psychosocial burden from TMD and to compare this impact among specific TMD diagnoses. It would also allow us to compare TMD with other oral diseases where OHRQoL scores are already available.9–11 By comparing the impact of a specific disease to the level of impaired oral health in the general population, one would be able to derive the psychosocial impact due to that disease (in our case to a specific TMD diagnosis)—a research goal which has so far not been targeted for oral disorders. This relative impact is important from a theoretical point of view because it would characterize the perceived burden from a specific oral disease in relation to other oral diseases found in the general population and from a therapeutic point of view because it would characterize the level of psychosocial impact potentially accessible to treatment. The aim of this study was to derive the unique functional and psychosocial impact due to TMD by comparing the level of impaired OHRQoL in patients with a RDC/TMD axis I diagnosis with general population subjects unaffected by TMD (having no specific TMD diagnosis and a subgroup with absolutely no TMD signs/symptoms).
2.
Material and methods
2.1.
Subjects, study design, and setting
TMD patients were recruited from January 2001 until July 2006 as a series of consecutive adult patients seeking treatment for masticatory muscle and TMJ problems at the Department of Prosthodontics, Martin Luther University (Halle/Salle), and the Department of Prosthodontics and Materials Science, University of Leipzig. These departments are staffed with a small group of dentists experienced with TMD management and provide primary care for both self-referred and professionally referred TMD patients. Reliability of RDC/TMD examination has been investigated in previous reports12,13 and found to be sufficient. A total of 471 patients, aged at least 14 years of age (mean age S.D.: 38.6 15.6 years, 76% women), were available who had at least one diagnosis according to the German version14 of the research diagnostic criteria for temporomandibular disorders, RDC/TMD.15 Of these patients, 293 had a single RDC/TMD axis I diagnosis, 138 had two, and 40 had three or more axis I diagnoses.
To determine the specific impact due to TMD suitable subjects for comparison were selected from a probability sample of the general population in the metropolitan area of Halle/Saale and surrounding areas, Germany (N = 163, mean age S.D.: 38.3 11.3 years, 67% women).16 These subjects were examined clinically to record all components of the RDC/ TMD and the Helkimo-index. This examination took place in 1999. The RDC/TMD examination was used to identify those subjects without a definite RDC/TMD diagnosis (N = 135; mean age S.D.: 38.5 11.5 years, 65% women). The Helkimo-index was used to identify a subgroup of these 135 subjects who had no signs or symptoms of TMD (N = 35, mean age S.D.: 36.1 10.7 years, 49% women). According to the Helkimoindex,17 TMD symptoms were defined as patient’s report of TMJ sounds, feeling of fatigue or of stiffness on awaking or on movements of the lower jaw, difficulties in opening the mouth wide, locking, jaw luxation, pain on movement of the mandible, and pain in the region of the TMJ or of the masticatory muscles. Clinical signs were defined as impaired range of movement of the mandible, impaired TMJ function, muscle pain, TMJ pain, and pain on movement of the mandible.
2.2. Functional and psychosocial TMD impact characterized by oral health-related quality of life The outcome of the study was the functional and psychosocial impact due to the specific TMD. It was conceptualized as the difference between the mean of impaired OHRQoL in patients with a specific axis I disorder minus the mean of impaired OHRQoL in general population subjects without any TMD sign/ symptom or TMD diagnosis. The influence of number of axis I diagnoses was analyzed by comparisons between patients with two or more axis I diagnoses and patients with a specific single one. The functional and psychosocial impact was conceptualized using OHRQoL. This construct was measured using OHIP-G, the German version16 of the oral health impact profile.18 The OHIP-G has 49 items derived from the English-language OHIP and four items specific for the German population. For each OHIP question, subjects were asked how frequently they had experienced the impact in the last month. Responses were made on a scale 0—never, 1—hardly ever, 2—occasionally, 3— fairly often, and 4—very often. OHRQoL impairment was characterized by the OHIP-G summary score (OHIP-G49)—the sum of all 49 item frequencies contained in the English-language OHIP (the four German-specific items were omitted to maintain international comparability). For the purpose of clarity the OHIPG49 summary score will simply be referred to as ‘OHIP score’. Reliability of OHRQoL measured by OHIP was assessed by calculating Cronbach’s alpha, which is a measure of the construct’s internal consistency (alpha: 0.95 for TMD patients and 0.96 for the general population subjects).
2.3. Diagnoses and classification of physical TMD diagnoses Patients were examined using the RDC/TMD. They consist of physical (axis I) and psychosocial (axis II) measures to assign axis I and axis II diagnoses. Since axis I diagnoses are not mutually exclusive each patient can have up to 5 out of 8
journal of dentistry 35 (2007) 643–650
Table 1 – Physical diagnoses (axis I measures) according to the research diagnostic criteria for temporomandibular disorders Main groups
Diagnoses
I: Myofascial pain
Ia: Myofascial pain without limited opening Ib: Myofascial pain with limited opening
II: Disc displacement
IIa: Disc displacement with reduction IIb: Disc displacement without reduction, with limited opening IIc: Disc displacement without reduction, without limited opening
III: Arthralgia, osteoarthritis, and osteoarthrosis
IIIa: Arthralgia IIIb: Osteoarthritis of the TMJ IIIc: Osteoarthrosis of the TMJ
possible diagnoses (Table 1), one of main group I, and two of main group II and III, one for each joint, respectively. The German version of RDC/TMD axis II is identical to the Englishlanguage original, including a graded chronic pain status (GCPS) score, a jaw disability score and measures to assess depression and somatization. The only difference compared to the English language version is that the latter two constructs (depression and somatization) are assessed according to recommendations of the working group on pain assessment of the German chapter of the international association for the study of pain.19 The ‘Allgemeine Depressionsskala’,20 the German translation of the center for epidemiological studies depression scale (CES-D),21 is used to assess depression whilst the ‘Beschwerden-Liste’22 is used to assess somatization. The reliability of the clinical examination for participating examiners was considered sufficient.12,13
2.4.
645
Statistical analyses
OHIP summary scores are presented as means and their 95% confidence intervals for TMD patients with a single diagnosis classified according to RDC/TMD axis I and for general population subjects without any TMD diagnosis and the subgroup without any TMD sign or symptom. Differences in OHIP score between subject groups were tested using t-tests. The null hypotheses for the statistical tests were: TMD has no significant effect on OHRQoL assessed with the OHIP. To interpret the differences between patients and population subjects in relation to each other, additional analyses were performed. The magnitude of the effect of each single diagnosis and main group diagnosis was calculated according to Cohen.23 The effect size (Cohen’s d) is the difference between the means of two independent groups divided by standard deviation of either group. It was calculated comparing the OHIP mean score of each single diagnosis or main group diagnosis with the mean score of subjects without any TMD sign or symptom. Due to differences in standard deviations between patients and population subjects, a pooled standard deviation was calculated for each comparison. All analyses were performed using the statistical software package STATA (Stata Statistical Software: Release 9. College Station, TX: StataCorp LP), with the probability of a type I error set at the 0.05 level.
3.
Results
3.1.
RDC/TMD axis I single diagnoses
All diagnoses presented considerable impairment to oral health-related quality of life (Fig. 1). OHIP means for diagnoses were between 27.5 and 56.2 points. This was substantially
Fig. 1 – OHRQoL in patients with single RDC/TMD clinical diagnoses in comparison with general population subjects without any diagnosis according to RDC/TMD (no Dx) and the subgroup without any sign or symptoms of TMD (Helkimo Ai0Di0 classification).
646
journal of dentistry 35 (2007) 643–650
higher than for general population subjects without any sign or symptom of TMD (OHIP score: 9.7) or general population subjects without any RDC/TMD diagnosis (OHIP score: 14.8). All diagnoses exhibited a substantial and statistically significant OHRQoL effect (Fig. 3). The diagnosis with the highest impaired OHRQoL was ‘‘myofascial pain without limited opening’’ (OHIP score: 56.2) which was about 10 points higher than patients with ‘‘myofascial pain with limited opening’’. The lowest OHRQoL level was observed for patients with ‘‘disc displacement (DD) with reduction’’ (OHIP score: 27.5). However, the level of impaired OHRQoL was still substantially higher than that in the general population. Patients with ‘‘DD without reduction with limited opening’’ had a higher impact of OHRQoL—the OHRQoL difference compared with ‘‘DD with reduction’’ was more than 15 points which was statistically significant ( p = 0.003). Statistically non-significant differences were observed for patients with ‘‘DD without reduction and without limited opening’’ compared with the other RDC/TMD group II diagnoses. Neither ‘‘arthralgia’’, ‘‘osteoarthritis’’, nor ‘‘osteoarthrosis’’ differed substantially or statistically significantly in their OHRQoL means.
3.2.
RDC/TMD main diagnostic groups
When specific diagnoses were grouped according to the three major RDC/TMD diagnostic groupings, the highest impact on OHRQoL was observed for patients with a group I (myofascial pain) diagnosis (Fig. 2). The lowest level of impaired OHRQoL was observed in patients with group II (disc displacements). The difference between group I and group II of 23.1 points was statistically significant ( p < 0.001). Patients with a group III (TMJ inflammatory and degenerative disorders) diagnosis differed statistically significantly
( p < 0.001) from patients in group II. The difference of 9 points between group I and III almost reached the level of statistical significance ( p = 0.08).
3.3. Impact of RDC/TMD axis I diagnoses and RDC/TMD main groups on OHRQoL To show the functional and psychosocial impact associated with individual TMD diagnoses, we subtracted the mean OHRQoL of the general population subjects with no sign or symptom of TMD from the scores associated with each RDC/ TMD axis I diagnosis. As can be seen from Fig. 3 each diagnosis had a considerable impact on the OHRQoL as represented by the height of the bars. None of the 95% confidence intervals included the value ‘‘0’’, i.e., all impacts were statistically significant ( p < 0.05). A similar approach was used to show the functional and psychosocial impact associated with the three main RDC/TMD diagnostic groups (Fig. 4). As expected from the previous results, every impact in comparison to the non-TMD-population was statistically significant ( p < 0.05). The effect sizes for single diagnosis ranged from 1.02 for ‘‘DD without reduction without limited opening’’ and 1.06 for ‘‘DD with reduction’’ up to 2.04 for ‘‘myofascial pain without limited opening’’ and within the three main diagnostic groups from 1.11 for group II (disc displacements) up to 1.68 for group III (TMJ inflammatory and degenerative disorders) and 1.75 for group I (myofascial pain). According to Cohen all effect sizes could be defined as large.23
3.4. Influence of number of RDC/TMD axis I diagnoses on OHRQoL For patients with a single axis I diagnosis a less impaired OHRQoL (OHIP score: 39.0) was observed than for patients with
Fig. 2 – OHRQoL in patients with single TMD diagnoses grouped according to the three main RDC/TMD groups in comparison with general population subjects without any diagnosis according to RDC/TMD (no Dx) and the subgroup without any sign or symptoms of TMD (Helkimo Ai0Di0 classification).
journal of dentistry 35 (2007) 643–650
647
Fig. 3 – OHRQoL impact associated with single RDC/TMD diagnoses. Baseline represents the mean OHIP summary score for general population subjects with no sign or symptom of TMD (Helkimo Ai0Di0 classification). two diagnoses (OHIP score: 52.9). The difference was statistically highly significant ( p < 0.001). For patients with three or more axis I diagnoses the observed OHIP score of 48.9 did not differ significantly from the OHIP score of patients with two diagnoses ( p = 0.48). Among patients with a single painrelated diagnosis (myofascial pain, arthralgia, or arthritis) an additional group II diagnosis (disc displacement) did not appear to have a further impact on OHRQoL; the OHIP score was almost the same (49.2 versus 47.1, p = 0.64). In contrast, patients with two pain-related diagnoses had significantly higher impaired OHRQoL than patients with a single one (58.9 versus 49.2, p = 0.03).
4.
Discussion
Temporomandibular disorders present a variety of psychosocial impacts. Using a standardized and widely used instrument, the oral health impact profile, we showed that specific physical TMD diagnoses have different impacts on patients.
4.1. Differences in the psychosocial impact across TMD diagnoses The psychosocial impact of TMD is related to signs and symptoms resulting in specific diagnoses. Diagnoses asso-
Fig. 4 – OHRQoL impact associated with the three main RDC/TMD groups. Baseline represents the mean OHIP summary score for general population subjects with no sign or symptom of TMD (Helkimo Ai0Di0 classification).
648
journal of dentistry 35 (2007) 643–650
ciated with pain (e.g., myofascial pain, arthralgia) have a higher impact than non-pain-related diagnoses (e.g., disc displacement with reduction). Within the TMD pain diagnoses it was observed that subjects with myogenous disorders presented more impaired oral health-related quality of life than subjects with an arthrogenous pain disorder. This was particularly obvious when effect sizes were used for characterizing the group differences. This finding is in line with Macfarlane et al.24 In TMD subjects with signs or symptoms of TMD, individuals with temporomandibular joint pain had the lowest level of disability while subjects with pain in and around the temples (myogenous pain) presented the highest proportion taking medicine for their complaints. Bush and Harkins25 reported higher pain-related limitations in activities of daily living in patients with myogenous pain than in patients with arthrogenous pain. We did not find large differences between myofascial pain with and without limited mouth opening. This is somewhat surprising because limited mandibular mobility is a core symptom and clinical sign of TMD and our findings are also in contrast to other studies. For example, Miller et al.26 found that TMD patients with a high temporomandibular opening index (i.e., increased limitation of opening) had more severe signs and symptoms of TMD than patients with a low index. Obviously, the condition myofascial pain itself has a certain impact on the individual but the limited mouth opening does not appear to add substantially to its genuine impact. The relative impact of limited opening on patients perceived OHRQoL seems to be too small to be detected with the OHIP. The OHIP questionnaire has quite a number of items related to oral functions but there are even more items describing psychological discomfort and disability/handicap. This situation may decrease the likelihood that significant differences due to the functional limitation are detected. Sample size is another important consideration when investigating group differences. Although disc displacements with reduction had the lowest OHRQoL scores they still had a substantial influence on perceived health. Although this disorder is often not associated with pain, subjects are often worried about their clicking jaw and feel uncomfortable which prompts them to seek treatment or information about their condition. This situation is reflected in an increased OHIP score. That joint sounds are associated with psychological variables has been demonstrated.27,28 In a German national survey it was reported that joint sounds affect the OHRQoL.29 ‘‘Bothering joint noises’’ were mentioned by 11% of the subjects age 16 and 79 years. In contrast, among patients with a painrelated diagnosis (myofascial pain, arthralgia, or arthritis) disc displacement seems not to add to the impact on OHRQoL. The unique impact is an important concept because for each (oral) condition the observed impairment (measured by an oral health-related quality of life instrument) has two parts. The first part is the ‘‘normal level’’ of OHRQoL in a particular population. The second part of the observed impact is due to unique impact of the conditions the patient suffers from. When presenting the unique impact of TMD diagnoses one important aspect is the comparison group. The magnitude of the unique TMD impact depends on the definition of the
comparison group without TMD diagnosis. Although general population subjects are the most plausible choice for comparison, they may have some signs and symptoms of TMD—but insufficient to warrant an RDC/TMD diagnosis. Such signs and symptoms may nevertheless influence OHRQoL—a situation observed in our study where subjects without a diagnosis had a more than 50% higher OHRQoL impact compared to subjects without any TMD sign or symptom. Due to the case definition in the RDC/TMD not all subjects with signs and symptoms of TMD can be assigned a specific TMD diagnosis. The RDC/TMD classification system is designed this way to derive a clinically meaningful characterization of the status of temporomandibular joints and masticatory muscles. Therefore, next to subjects without a RDC/TMD diagnosis, a second definition of a comparison group seemed to be worthwhile. For this approach we decided to apply the Helkimo-index.17 It provides an anamnestic and clinical dysfunction index. To receive a ‘‘0’’ for both indices, signs of TMD must not be reported by the patient and clinical symptoms of TMD must not be found in the clinical examination. This definition of not having TMD is stringent and comprehensible and thus a limited sample size resulted. However, considering the ambiguity what is regarded ‘‘free of TMD’’, the Helkimo-index derived definition seemed to be an appropriate choice to define subjects without any sign or symptom of TMD. Differences between the prevalence of signs and symptoms of TMD and the frequency of diagnoses in a particular population were observed in a previous prevalence study in our clinical TMD population.30 Although for clinical purposes a diagnosis is necessary for treatment, the results presented here support the notion that a continuum of psychosocial impairment ranging from its lowest levels in subjects without any TMD sign or symptom to probably very high levels in subjects with dysfunctional chronic TMD pain exist. The level of impaired OHRQoL could be used to characterize the severity of TMD. The magnitude of unique OHRQoL impact due to TMD is similar to the overall burden of impaired oral health-related quality of life in treatment seeking prosthodontic patients,31 institutionalized elderly,32 neurologically based facial pain patients33 and patients with burning sensations and pain in the oral mucosa with or without lesions, or skeletal malocclusion.34 These findings are in contrast with Reisine et al., who investigated the impact of different dental conditions on patients’ quality of life by using the sickness impact profile.35 In that study TMD patients presented a higher impact than those with periodontal diseases, with removable partial dentures with treatment need, or in comparison with a control group. The difference in findings may reflect variations in the tools being used or the patient populations studied.
4.2.
Methodological aspects of the study
A major strength of the study is the use of standardized and internationally widely recognized instruments, the OHIP and the RDC/TMD. Nevertheless, the limited sample size in some of the specific diagnoses is a limitation. Starting out with 471 patients, only 62% of this treatment seeking patients had a single specific diagnosis according to RDC/TMD. The
journal of dentistry 35 (2007) 643–650
co-occurrence of several diagnoses in a particular TMD patient is well-known.1–4 The low number of some specific diagnoses is also influenced by the rare occurrence of some conditions (e.g., disc displacement without reduction, arthrosis and arthritis). It is well-documented that myofascial pain, arthralgia, and disc displacement with reduction are the most frequent diagnoses in clinical samples36,37 as well as in population-based studies.38,39 In comparing the main RDC/ TMD groups the large number of patients with disc displacement with reduction among the three disc displacement diagnoses (group II) needs to be taken into account or there is a risk of underestimating the impact experienced by patients with disc displacement without reduction. In this study only the impact of physical conditions leading to a TMD diagnosis was regarded. The specific impact of conditions such as depression, somatization, and dysfunctional chronic pain was not investigated. However, it is well documented that there is a relationship between these conditions and OHRQoL,40 implying OHRQoL may be suitable to catch some of the impact of these conditions in a single measure. Summarizing the variety of psychosocial distress into one summary score has some advantages. It allows for intra and inter subject comparisons within a defined disease as well as comparing between different oral diseases. Furthermore reference values for different diseases, so called ‘norms’, can be interpreted from the scores. However, a summary score has also some disadvantages. Profiles of different psychosocial aspects in TMD patients, which might individually be important to their diagnosis and management, are lumped together in one summary score. Important information relevant for treatment planning and evaluation might therefore be lost. To overcome this disadvantage, evaluation of the oral health-related quality of life summary score could be supplemented by the assessment of OHRQoL dimensions or by reporting the presence or severity of single items. For our statistical analysis we chose parametric tests, e.g., t-tests, which require that the means are normally distributed, not the original data. The use of parametric tests for our analyses is supported by the ‘central limit theorem’ which says that means are normally distributed regardless of the shape of the original distribution when the number of subjects is not small as in our study.41 Multiple testing may occur as another methodological challenge in our study. However, we did not want to control the error rate per study. Therefore, we did not adjust our statistical tests for multiple testing, i.e., we did not reduce the alpha level. We believe that different characteristics were examined in our study and it is not desirable to control the error rate of the whole study, since this would reduce the statistical power for each characteristic. Considering all methodological pros and cons of our study, the unique impact due to TMD is an important concept and may have important clinical implications. If one assumed that before the onset of TMD patients had similar OHRQoL to the general population then the magnitude of psychosocial impairment characterized in this study may be accessible to treatment. It follows that the OHRQoL impact due to TMD might represent, on average, what would be hoped for as treatment benefit which is equally important for patient and treatment providers.
649
references
1. Yap AU, Dworkin SF, Chua EK, List T, Tan KB, Tan HH. Prevalence of temporomandibular disorder subtypes, psychologic distress, and psychosocial dysfunction in Asian patients. Journal of Orofacial Pain 2003;17:21–8. 2. List T, Dworkin SF. Comparing TMD diagnoses and clinical findings at Swedish and US TMD centers using research diagnostic criteria for temporomandibular disorders. Journal of Orofacial Pain 1996;10:240–53. 3. Manfredini D, Segu M, Bertacci A, Binotti G, Bosco M. Diagnosis of temporomandibular diaorders according to RDC/TMD axis I findigns, a multicenter Italian study. Minerva Stomatologica 2004;53:429–38. 4. Celic R, Panduric J, Dulcic N. Psychologic status in patients with temporomandibular disorders. International Journal of Prosthodontics 2006;19:28–9. 5. Huang GJ, LeResche L, Critchlow CW, Martin MD, Drangsholt MT. Risk factors for diagnostic subgroups of painful temporomandibular disorders (TMD). Journal of Dental Research 2002;81:284–8. 6. McCreary CP, Clark GT, Oakley ME, Flack V. Predicting response to treatment for temporomandibular disorders. Journal of Craniomandibular Disorders 1992;6:161–9. 7. Grossi ML, Goldberg MB, Locker D, Tenenbaum HC. Reduced neuropsychologic measures as predictors of treatment outcome in patients with temporomandibular disorders. Journal of Orofacial Pain 2001;15:329–39. 8. Epker J, Gatchel RJ. Prediction of treatment-seeking behavior in acute TMD patients: practical application in clinical settings. Journal of Orofacial Pain 2000;14:303–9. 9. Segu M, Collesano V, Lobbia S, Rezzani C. Cross-cultural validation of a short form of the oral health impact profile for temporomandibular disorders. Community Dentistry and Oral Epidemiology 2005;33:125–30. 10. McMillan AS, Leung KC, Leung WK, Wong MC, Lau CS, Mok TM. Impact of Sjo¨gren’s syndrome on oral health-related quality of life in southern Chinese. Journal of Oral Rehabilitation 2004;31:653–9. 11. Llewellyn CD, Warnakulasuriya S. The impact of stomatological disease on oral health-related quality of life. European Journal of Oral Sciences 2003;111:297–304. 12. John MT, Zwijnenburg AJ. Interobserver variability in assessment of signs of TMD. International Journal of Prosthodontics 2001;14:265–70. 13. Schmitter M, Ohlmann B, John MT, Hirsch C, Rammelsberg P. Research diagnostic criteria for temporomandibular disorders: a calibration and reliability study. Journal of Craniomandibular Practice 2005;23:212–8. 14. John MT, Hirsch C, Reiber T, Dworkin S. Translating the research diagnostic criteria for temporomandibular disorders into German: evaluation of content and process. Journal of Orofacial Pain 2006;20:43–52. 15. Dworkin SF, LeResche L. Research diagnostic criteria for temporomandibular disorders: review, criteria, examinations and specifications, critique. Journal of Craniomandibular Disorders 1992;6:301–55. 16. John MT, Patrick DL, Slade GD. The German version of the oral health impact profile—translation and psychometric properties. European Journal of Oral Sciences 2002;110:425–33. 17. Helkimo M. Studies on function and dysfunction of the masticatory system. II. Index for anamnestic and clinical dysfunction and occlusal state. Swedish Dental Journal 1974;67:101–19. 18. Slade GD, Spencer AJ. Development and evaluation of the oral health impact profile. Community Dental Health 1994;11:3–11.
650
journal of dentistry 35 (2007) 643–650
19. Kro¨ner-Herwig B, Denecke H, Glier B, Klinger R, Nilges P, Redegeld M, et al. Qualita¨tssicherung in der Therapie chronischen Schmerzes. Ergebnisse einer Arbeitsgruppe der Deutschen Gesellschaft zum Studium des Schmerzes (DGSS) zur psychologischen Diagnostik. IX. Multidimensionale Verfahren zur Erfassung schmerzrelevanter Aspekte und Empfehlungen zur Standarddiagnostik. Der Schmerz 1996;10:47–52. 20. Hautzinger M, Bailer M. Allgemeine Depressionsskala (ADS). Weinheim: Beltz; 1995. 21. Radloff L. The CES-D scale: a self-report depression scale for research in the general population. Applied Psychological Measurement 1977;1:385–401. 22. Von Zerssen D. Die Beschwerden-Liste. Weinheim: Beltz; 1976. 23. Cohen J. Statistical power analysis for the behavioral sciences. 2nd ed. Hillsdale, NJ: Lawrence Earlbaum Associates; 1988. 24. Macfarlane TV, Blinkhorn AS, Davies RM, Kincey J, Worthington HV. Oro-facial pain in the community: prevalence and associated impact. Community Dentistry and Oral Epidemiology 2002;30:52–60. 25. Bush FM, Harkins SW. Pain-related limitation in activities of daily living in patients with chronic orofacial pain: psychometric properties of a disability index. Journal of Orofacial Pain 1995;9:57–63. 26. Miller VJ, Karic VV, Myers SL. Differences in initial symptom scores between myogenous TMD patients with high and low temporomandibular opening index. Journal of Craniomandibular Practice 2006;24:25–8. 27. Spruijt RJ, Hoogstraten J. Symptom reporting in temporomandibular joint clicking: some theoretical considerations. Journal of Craniomandibular Disorders 1992;6:213–9. 28. Spruijt RJ, Wabeke KB. Psychological factors related to the prevalence of temporomandibular joint sounds. Journal of Oral Rehabilitation 1995;22:803–8. 29. John MT, LeResche L, Koepsell TD, Hujoel PP, Miglioretti DL, Micheelis W. Oral health-related quality of life in Germany. European Journal of Oral Sciences 2003;111: 483–91. 30. Gabler M, John MT, Reiber T. Die mehrdimensionale Charakterisierung einer Patientenpopulation mit
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
kraniomandibula¨ren Dysfunktionen. Deutsche Zahna¨rztliche Zeitschrift 2001;56:332–4. John MT, Szentpetery A, Slade G, Setz JM. Oral healthrelated quality of life in patients treated with fixed, removable and complete dentures 1 month and 6 to 12 month after treatment. International Journal of Prosthodontics 2004;17:503–11. Hassel AJ, Koke U, Schmitter M, Rammelsberg P. Factors associated with oral health-related quality of life in institutionalized elderly. Acta Odontologica Scandinavica 2006;64:9–15. Murray H, Locker D, Mock D, Tenenbaum HC. Pain and the quality of life in patients referred to a craniofacial pain unit. Journal of Orofacial Pain 1996;10:316–23. Larsson P, List T, Lundstrom I, Marcusson A, Ohrbach R. Reliability and validity of a Swedish version of the oral health impact profile (OHIP-S). Acta Odontologica Scandinavica 2004;62:147–52. Reisine ST, Fertig J, Weber J, Leder S. Impact of dental conditions on patients’ quality of life. Community Dentistry and Oral Epidemiology 1989;17:7–10. Kino K, Sugisaki M, Haketa T, Amemori Y, Ishikawa T, Shibuya T, et al. The comparison between pains, difficulties in function, and associating factors of patients in subtypes of temporomandibular disorders. Journal of Oral Rehabilitation 2005;32:315–25. Reiter S, Eli I, Gavish A, Winocour E. Ethnic differences in temporomandibular disorders between Jewish an Arab populations in Israel according to RDC/TMD evaluation. Journal of Orofacial Pain 2006;20:36–42. Truelove EL, Sommers EE, LeResche L, Dworkin SF, Von Korff M. Clinical diagnostic criteria for TMD. New classification permits multiple diagnoses. Journal of the American Dental Association 1992;123:47–54. Plesh O, Sinisi SE, Crawford PB, Gansky SA. Diagnoses based on the research diagnostic criteria for temporomandibular disorders in a biracial population of young woman. Journal of Orofacial Pain 2005;19:65–75. John MT, Reißmann DR, Schierz O, Wassell RW. Oral healthrelated quality of life in patients with temporomandibular disorders. Journal of Orofacial Pain 2007;21:46–54. Norman GR, Streiner DL. PDQ statistics. 2nd ed. St. Louis: Mosby; 1996.