Temporomandibular disorders (TMD) are among the most frequent musculoskeletal pain conditions, affecting around 5% to 12% of the US population and 3% of Japanese population. Long-standing controversy over the diagnosis and treatment of TMD continues,[3–6] and no initial management of TMD-related pain for general dentists has yet been standardized. A recent study by the National Dental Practice-Based Research Network (PBRN) and Dental PBRN Japan (JDPBRN) identified significant variation among practicing dentists regarding TMD-related pain. For example, 64% of US dentists and 58% of Japanese dentists reported using occlusal adjustment, despite the fact that the clinical practice guideline recommends against occlusal adjustment as initial treatment for TMD because of its irreversibility and uncertainty over its effectiveness. These findings suggest the presence of an evidence-practice gap in clinical practice for TMD-related pain. These circumstances might lead to a worsening of the difficulties already experienced by dentists in the diagnosis and treatment of TMD. Previous studies suggest that TMD-related pain impacts patients’ lives strongly and is connected with feelings of hopelessness and despair.[9–11] A qualitative interview study revealed that dentists recognized that psychological factors play an important role in the development and maintenance of TMD-related pain and felt inadequately equipped to manage this condition. A previous study suggested that about 50% of dentists felt insecure concerning TMD diagnostics, therapy decisions and treatment, and there is high need for offering continuing education in TMD. A systematic review suggested that understanding clinicians’ perceived barriers or misperception is important in bridging the evidence-practice gap, and that identifying these factors is better done using qualitative methods.
To our knowledge, however, dentist distress regarding TMD-related pain has not been evaluated. Understanding this distress may aid in bridging the evidence-practice gap. Therefore, the objectives of this study were to evaluate dentist distress when seeing patients with TMD-related pain qualitatively and identify specific characteristics that are significantly associated with dentist distress quantitatively.
2.1 Study design
The study was conducted using a cross-sectional design based on a questionnaire survey that used mixed methods integrating both quantitative and qualitative data in the study. Approval was obtained from the Institutional Review Board of Kyushu Dental University (No. 13-73) and the study was conducted in accordance with the World Medical Association Declaration of Helsinki. Participants were provided informed consent prior to participation.
The study evaluated dentists working in outpatient dental practices and affiliated with the JDPBRN (n = 148). The JDPBRN is a research network and consortium of dental practices with a broad representation of practice types, treatment philosophies, and patient populations, and has a shared mission with the DPBRN, now called the National Dental PBRN (http://NationalDentalPBRN.org). Participants were enrolled via the JDPBRN website (http://www.dentalpbrn.jp/) and a targeted mail campaign. The JDPBRN network regions cover all 7 major districts of Japan, namely Hokkaido, Tohoku, Kanto, Chubu, Kansai, Chugoku-Shikoku, and Kyushu. Each of these regions has a Regional Coordinator, who was tasked with distribution and collection of the questionnaires. Participants completed the questionnaire themselves and mailed it to the Regional Coordinator using a preaddressed envelope. On receipt, the Regional Coordinator reviewed all questionnaires for completeness.
Participating dentists were asked about their own and their patients’ demographic information. They were also asked about difficulties experienced by patients in their practice who have TMD pain, such as “cannot eat,” “fear of not being able to open the mouth,” and “shoulder stiffness and headache”; duration of TMD-related pain in their patients; and dentist awareness of the existence of TMD practice guidelines or experience of having read them. In addition, participants were asked about their biggest difficulties when seeing patients with TMD-related pain in an open-ended questionnaire survey. The final version of this questionnaire is available at http://www.dentalpbrn.jp/image/study2questionnaire.pdf.
2.4 Qualitative analysis
Participants were asked to describe their opinions regarding “What is the most distressing aspect for you when you treat patients with TMD-related pain?” in a free answer method. Dentist distress on seeing patients with pain related to TMD was analyzed using thematic analysis, as described by Braun and Clarke.[17,18] Briefly, thematic analysis consists of 6 phases: familiarization with the data, coding, searching for themes, reviewing themes, defining and naming themes, and writing-up the results. All processes were actively discussed among 2 epidemiologists and 2 dentists.
2.5 Quantitative analysis (statistical analysis)
A descriptive analysis was conducted, and the results were expressed in terms of the mean, standard deviation (SD), and frequency. We determined the numbers (percentage) of JDPBRN dentists and patients’ demographics. One-way analysis of variance (ANOVA) and residual analysis were then conducted to examine the relationship between independent variables and the dentists’ distress theme as a dependent variable. The post hoc test (Fisher–Hayter test) was conducted when the results of one way ANOVA were statistically significant. Independent variables were gender, age, percentage of clinicians who knew of the guideline, percentage who had read the guideline, patients with severe TMD-related pain, number of TMD pain patients treated per month, difficulties experienced by patients and duration of pain. Statistical significance was set at P < .05. All statistical analyses were performed with STATA/SE (version 13; STATA Corporation, College Station, TX).
3.1 Demographic information of participants
Questionnaires were provided to 148 dentists, and 113 (76%) responses were received. Demographic characteristics are shown in Table 1. Mean age (SD) was 44 ± 11. Participants were mainly male (N = 92, 84%), and were all Asian by race or ethnicity. Respondents reported that their patients experienced TMD difficulties that included shoulder stiffness (37.5%), headache (28.8%), cannot eat (22.7%), and fear of not being able to open the mouth (14.9%). Sixty-two (56.9%) dentists knew of the existence of the TMD practice guidelines and 44 (41.5%) had read them.
3.2 Dentist distress in the management of chronic pain control according to the thematic analysis
Thematic analysis of the freely descriptive data generated 6 themes, namely difficulty in predicting therapeutic effect and prognosis (N = 33); difficulty in diagnosis (N = 22); difficulty in the decision about whether to do occlusal adjustment (N = 16); difficulty in specifying a cause (N = 13); difficulty in communicating with patients and mental factors (N = 12); and health insurance system barriers (N = 1). These results are described in Table 2; each theme was supported by more than 12 mentions except theme 6. Since theme 6 was supported by only 1 mention, we excluded theme 6 from further quantitative analysis.
3.3 Factors associated with dentist distress in the management of chronic pain control
Factors affecting dentists’ distress in the management of chronic pain control are shown in Table 3. Patient and dentist characteristics were associated with the type of dentist distress in management of chronic pain control. Clinicians who reported difficulties in deciding whether to do occlusal adjustment saw more patients who experience shoulder stiffness and headache (one way ANOVA, P = .008 and P = 0.022, respectively). Dentists’ knowledge of the TMD guidelines was significantly associated with a lower percentage of dentist difficulties in predicting therapeutic effect and prognosis (residual analysis, P = .010).
The results of this study identified 6 themes of dentists’ perceived distress when managing chronic pain control in TMD. One-way ANOVA and residual analysis suggested that both patient characteristics (such as difficulty with shoulder stiffness and headache) and dentist characteristics (such as knowing of the existence of TMD guidelines) were associated with dentist distress in the management of chronic pain control.
Thematic analysis extracted 6 dentist distress factors in the practice of TMD-related pain, including dentist and patient communication, etiology, diagnosis, treatment, prognosis, and social health insurance system. These results suggest that clinician distress occurs in many areas, including those at the patient level, dentist level, and social health insurance system level. As previously noted, psychological factors play an important role in the management of TMD-related pain, and our analysis also suggested that communication with patients who have psychological factors was difficult. Since TMD-related pain is multidimensional, difficulties in specifying specific causes have been reported. In addition, TMD-related pain is a long-term condition, and dentists felt distress in predicting its therapeutic effect and prognosis. Regarding the social health insurance system, as dentist diagnosis and treatment varies among different kinds of health insurance coverage,[20–27] practice pattern could be largely influenced by the social insurance system.
This study also revealed dentists’ perceived distress over decisions surrounding occlusal adjustment. A previous study suggested that dentists feel inadequately equipped to diagnose or treat TMD-related pain, and that they recognized that psychological factors could play a role in the development and maintenance of TMD-related pain. Although the clinical practice guideline recommends that, because of the irreversible and uncertain nature of TMD, occlusal adjustment should not be performed as initial treatment, as many as 64% of US and 58% of Japanese dentists initially use occlusal adjustment in their practice.[1,7] This apparent evidence-practice gap in occlusal adjustment may cause dentist distress over decisions about this treatment.
Additional quantitative analysis revealed that dentists’ distress over occlusal treatment was related to the dentist having a higher percentage of patients who experienced shoulder stiffness and headache. Treatment of patients with TMD might be more difficult when they experienced additional problems such as shoulder stiffness and headache. For this reason, dentists may perceive greater difficulty in treatment decisions and tend to seek possibilities for the cure of TMD-related pain. Finally, they may try occlusal adjustment even if it is not recommended as a first choice. Previous research in Japan found that the most frequent symptoms accompanying TMD were shoulder stiffness (53.1%) and headache (25.2%). This high prevalence of accompanying symptoms may be 1 reason for the high percentage of occlusal adjustment for TMD-related pain in Japan.
Dentists’ distress over the management of chronic pain control may be because of a lack of knowledge, although this study did not assess the relationship between dentists’ knowledge and their distress. Previous studies to assess knowledge of and beliefs about TMD were conducted in several countries.[29–32] In one study, the subject dentists mostly agreed with TMD experts regarding the “etiology” domain, but did not agree with them in the areas of “pathophysiology, diagnosis, and treatment,” and lacked knowledge of these areas. However, another study pointed out that dentist knowledge of TMD was lowest among the 4 domains of etiology, signs and symptoms, diagnosis, and treatment. These results suggest that dentists’ knowledge variation exists. In our study, we found a relationship between dentist recognition of the existence of the TMD guideline and lower distress on prognosis, which may suggest that greater knowledge of TMD-related pain could lower dentists’ prognostic distress, which had the highest percentage of all 6 distresses. Although our results did not show a significant association between experience with reading the guidelines and lower dentist distress, the association was in the same direction as knowledge of the existence of the guidelines. Further studies are needed to clarify the relationship between the clinical guidelines and clinician distress in the management of chronic pain.
The main strength of this study is its use of mixed methods (qualitative and quantitative analysis). Qualitative analysis is suitable for exploratory clarification of this phenomenon. Also, this study clarified factors associated with the themes revealed by quantitative analysis. A limitation of this study regarding selection bias also warrants mention. The subjects were not a random selection, but instead were responders to a recruitment request in the JDPBRN. Nevertheless, the subjects represented a reasonably diverse range of dental care from the 7 major geographical areas of Japan. Distributions by age and sex were consistent with the distribution of Japanese dentists, namely 80% men with an average age in the 40s. These characteristics support the generalizability of our results. Other limitations exist regarding unmeasured variables, such as the seniority of dentists or their psychological factors like personal distress tolerance and practicing in different social insurance systems, which may independently influence the dentist distress on the management of TMD-related pain. Finally, the results of this study may generalize only to Japan. Diverse practice guidelines and dentists’ practice patterns may make the results less generalizable to other countries.
Against the controversial background of an evidence-practice gap in the treatment of patients with TMD, we identified 6 themes of dentists’ distress in the management of chronic pain control of TMD. The percentage of patients in their practice who experienced difficult symptoms was associated with higher dentists’ distress in decision making for occlusal treatment. Further, dentist awareness of the existence of TMD clinical practice guidelines may lower dentist distress, particularly with regard to prognosis. Further studies to lower dentist distress and to fill the evidence-practice gap in TMD treatment are needed.
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