Pages 189, Language: English
Pages 191-204, Language: English
Aims: To investigate differences between higher and lower pain catastrophizers in the effects of hypertonic saline-evoked jaw muscle pain on pain perception and jaw movement.
Methods: Repetitive open/close jaw movements were recorded in 28 asymptomatic participants (20 men, 8 women; ages 25 to 62 years) during continuous infusion of 5% hypertonic saline or isotonic saline into the right masseter muscle. All participants completed the McGill Pain Questionnaire; the Depression, Anxiety and Stress Scales; and the Jaw Function Limitation Scale. They were divided into two groups depending on the median Pain Catastrophizing Scale score. Statistical analyses involved multivariate analysis of variance, independent samples or paired t tests, and Pearson correlations (statistical α: P < .05).
Results: Pain intensity, unpleasantness, perceived area, and pain rating indices were significantly (P < .05) elevated in higher pain catastrophizers during hypertonic saline-evoked pain in comparison with lower catastrophizers. The higher catastrophizers exhibited significantly (P < .05) slower jaw velocity than the lower catastrophizers during hypertonic saline infusion in comparison with IS infusion. In comparison with lower catastrophizers, there was a significantly greater change in the percentage of coefficient of variation between hypertonic saline and isotonic saline infusions in higher catastrophizers for closing velocity and opening and closing amplitude.
Conclusion: The increased reported pain intensity, pain areas, and pain rating indices are consistent with enhanced central sensitization processes in high-catastrophizing individuals. The slower velocity and greater variability of repetitive jaw movements in higher pain catastrophizing individuals in acute experimental pain may reflect changes in motor coordination as an example of avoidance behavior for the jaw motor system.
Keywords: jaw movement, orofacial pain, Pain Adaptation Model, pain catastrophizing, pain intensity
Pages 205-222, Language: English
Aims: To carry out a systematic review and meta-analysis comparing the effects of occlusal splint therapy ("usual treatment") and psychosocial interventions for the treatment of myofascial temporomandibular disorder (TMD) pain in adult patients.
Methods: Independent screening and evaluation of randomized clinical trials included comparisons between "usual treatment" based on splint therapy and psychosocial interventions for TMD treatment within electronic databases (PubMed/MEDLINE, CENTRAL, EMBASE), ongoing trials databases (Current Controlled Trials, ClinicalTrials.gov), and additional sources. The outcomes selected for the systematic review were self-reported pain, pain interference, unassisted jaw opening without pain, muscle pain upon palpation, depression, and somatization. The effect measures were analyzed using a random-effect model (Review Manager computer program).
Results: The outcomes "longterm self-reported pain" and "long-term depression" were significantly different for the comparisons of "usual treatment" and psychosocial interventions, and they favored the latter (P < .005 and P < .05, respectively). These results must be viewed with caution due to the limited number of studies available. A tendency toward greater improvements of psychological outcomes was observed for psychosocial interventions, while physical functioning was slightly more responsive to "usual treatment."
Conclusion: No evidence was found to distinguish the clinical effectiveness between "usual treatment" and psychosocial interventions for myofascial TMD pain. Future studies of TMD and related subdiagnoses should be reported according to core standardized outcomes to facilitate comparisons.
Keywords: meta-analysis, myofascial pain, oral myofascial pain, systematic review, temporomandibular disorders
Pages 223-232, Language: English
Aims: To explore patients' understanding of their orofacial pain, as this is an under-researched area despite emerging as a common aim of consultation.
Methods: Twelve people with chronic orofacial pain were interviewed shortly before their first consultation at a specialist facial pain clinic about their understanding of their pain, and they completed self-report measures of distress and pain interference. A day after the consultation, they wrote a short letter about how they now understood their pain and were then interviewed by phone. All accounts were analyzed using thematic analysis.
Results: Four themes emerged across preconsultation and postconsultation data: the need for information to counteract helplessness; worry as part of making sense of pain; validation of the pain experience (all predominant preconsultation); and the importance of trust (reflecting changes in understanding since consultation). Most patients changed their understanding of pain and resolved their worries to some extent, and they reported reduced distress and less interference.
Conclusion: Patients' fears and beliefs about chronic orofacial pain are dominated by worrying and searching for meaning before consultation. Information about their chronic pain condition counters feelings of helplessness and supports sense-making around pain when explanations are clear, are delivered sensitively from a trusted source, and take into account the patient's existing health beliefs; this promotes self-management. These findings underline the important functions of specialist consultation in achieving a shared accurate understanding of pain and options for treatment.
Keywords: chronic pain, pain explanation, qualitative analysis
Pages 233-242, Language: English
Aims: To examine (1) the occurrence of magnetic resonance imaging (MRI) signal changes in the painful regions of patients with atypical odontalgia (AO) and (2) the correlation of such findings to periapical bone defects detected with a comprehensive radiographic examination including cone beam computed tomography (CBCT).
Methods: A total of 20 patients (mean age 52 years, range 34 to 65) diagnosed with AO participated. Mean pain intensity (± standard deviation) was 5.6 ± 1.8 on a 0-10 numerical rating scale, and mean pain duration was 4.3 ± 5.2 years. The inclusion criterion was chronic pain (> 6 months) located in a region with no clear pathologic cause identified clinically or in periapical radiographs. In addition to a clinical examination and a self-report questionnaire, the assessments included radiographic examinations (panoramic, periapical, and CBCT images), and an MRI examination. Changes in MRI signal in the painful region were recorded. Spearman's rank correlation between radiographic and MRI findings was calculated.
Results: Eight of the patients (40%) had MRI signal changes in the pain region. The correlation to radiographic periapical radiolucencies was 0.526 (P = .003). Of the eight teeth displaying changes in MRI signal, six showed periapical radiolucency in the radiographs.
Conclusion: MRI examination revealed no changes in the painful region in a majority of patients with AO, suggesting that inflammation was not present. MRI findings were significantly correlated to radiographic findings.
Keywords: cone beam computed tomography, magnetic resonance imaging, orofacial pain, persistent dentoalveolar pain disorder, trigeminal pain
Pages 243-251, Language: English
Aims: To explore thoughts, experiences, and beliefs regarding temporomandibular disorders (TMD) among Sami women with and without TMD in order to gain insights into their health care experiences and to generate a hypothesis regarding factors associated with long-standing TMD.
Methods: Qualitative thematic interviews were conducted with a strategic sample of 17 Sami women, of whom 10 had a TMD diagnosis according to the Research Diagnostic Criteria for TMD and 7 age-matched women who had no signs or symptoms of TMD. Their ages were between 23 and 58 years. The thematic interviews were audiotaped, transcribed verbatim, and analyzed based on Grounded Theory, a qualitative methodology aiming to generate hypotheses grounded in the gathered data.
Results: The core category that evolved was "Grin(d) and bear it," which summarizes the Sami participants' various ways and stages of processing and handling the interacting categories (triggers, strains, distrust, and reconciliation with pain and/or difficulties in life). They described divergent as well as similar understandings of triggering factors. Maintaining factors were described as mental-physical strain and stress, and also a jaw-clenching behavior. Women without TMD contributed with factors that helped them to handle strains, reconcile, and stay healthy. They relied on strong social support.
Conclusion: Based on the analysis, the following hypothesis was generated: Women with TMD, associated headaches, and neck-shoulder pain may benefit from efforts aimed at empowering them to use their own abilities to reduce stress behavior, strain, and disuse of the jaw. Rehabilitation strategies in groups might increase their sense of coherence and increase social support, which seems to be more limited than in women with no symptoms of TMD.
Keywords: chronic pain, consultation, qualitative research, Sami, temporomandibular, women's health
Pages 252-260, Language: English
Aims: To evaluate the contraction pattern of masticatory muscles during sustained clenching tasks with or without experimental pain induced by glutamate injection into the masseter muscle. It was hypothesized that acute muscle pain could induce compensatory changes in the electromyographic (EMG) activity of the masticatory muscles.
Methods: Fifteen volunteers (seven males, mean age ± SD = 29.7 ± 1.1 years; eight females, mean age ± SD = 23.5 ± 1.2 years) were recruited in a crossover experimental study. All subjects participated in two randomized 20-minute experimental sessions. Each subject was asked to clench at 25% of the maximum voluntary contraction (MVC). After 10 minutes, isotonic saline or glutamate was injected in random order into the right masseter. EMG activity (root mean square [RMS] and mean power frequency [MPF]) was assessed in the masseter and anterior temporalis muscles on both sides. Pain and fatigue were assessed by 0-10 numeric rating scales (NRS) every minute. Differences between conditions (isotonic saline vs glutamate) for all the outcome parameters were analyzed by using a mixed effect model.
Results: The EMG activity of the masticatory muscles and pain and fatigue scores were not dependent on isotonic saline/glutamate injection (all P > .05). The RMS in the temporalis and masseter muscles increased with time (right masseter P = 0.001, left masseter P = .004, right temporalis P = .22, left temporalis P = .006), whereas the MPF decreased (right masseter P = 0.0001, left masseter P < .0001, right temporalis P = 0.51, left temporalis P = .0005). Scores for fatigue and pain increased during the experimental sessions (all P < .05).
Conclusion: Intramuscular injection of glutamate caused more pain than isotonic saline but did not affect the contraction pattern of the masticatory muscles during a sustained clenching task. This finding strongly suggests the adaptive capacity of the stomatognathic system in the presence of acute nociceptive inputs.
Keywords: experimental orofacial pain, surface electromyography, temporomandibular disorders, tooth clenching
Pages 261-268, Language: English
Aims: To determine the effect of low-intensity pulsed ultrasound (LIPUS) on cyclooxygenase-2 (COX-2) expression and related mechanisms by using cultured articular chondrocytes derived from porcine mandibular condyles after treatment with interleukin-1 beta (IL-1β).
Methods: Chondrocytes were derived from porcine mandibular condylar cartilage and cultured. The cells were treated with or without 10 ng/mL IL-1β. At the same time, the cells were exposed to LIPUS for 20 minutes. After LIPUS exposure, the conditioned medium was changed to a fresh one without IL-1β, and the cells were incubated for 0 to 24 hours. The effects of LIPUS on IL-1β-treated chondrocytes were examined in terms of the expression of p-integrin β1, COX-2, and phosphorylated extracellular signal-related kinase (p-ERK) 1/2 by real-time polymerase chain reaction (PCR) and Western blot analyses. Differences in the means among multiple groups were examined by oneway analysis of variance (ANOVA) for all groups at each time point, followed by a Scheffé multiple comparison test as a post-hoc test; Student t test was also used.
Results: COX-2 mRNA level was upregulated by the treatment with IL-1β and was suppressed significantly (P < .01) by LIPUS exposure. Furthermore, LIPUS enhanced gene expression and phosphorylation of integrin β, and it inhibited the expression of p-ERK 1/2.
Conclusion: LIPUS exposure inhibited IL-1β-induced COX-2 expression through the integrin β1 receptor followed by the phosphorylation of ERK 1/2. Despite the restricted duration of its effect, LIPUS is suggested to be a potential candidate as a preventive and auxiliary treatment to suppress the degradation of articular chondrocytes in temporomandibular joint osteoarthritis.
Keywords: cyclooxygenase-2 (COX-2), low-intensity pulsed ultrasound (LIPUS), mandibular condylar cartilage, mechanical stress, osteoarthritis (OA)
Pages 269-276, Language: English
Aims: To examine the expression of hypoxia inducible factor-lα (HIF-1α), vascular endothelial growth factor (VEGF), aggrecanase-1 (ADAMTS-4), and tissue inhibitor of metalloproteinase-3 (TIMP-3) in rat mandibular condylar chondrocytes under hypoxic conditions and examine the relationship of these expressed factors in early condylar cartilage growth.
Methods: CoCl2 was used to mimic a hypoxic microenvironment by chemically inducing hypoxia. Chondrocytes, which were obtained from the mandibular condyles of 3-week-old female Sprague-Dawley rats, were treated with 125 μmol/L CoCl2 for 48 hours. The HIF-1α, VEGF, ADAMTS-4, and TIMP-3 mRNA levels in chondrocytes were detected using a semiquantitative polymerase chain reaction (PCR) at 12, 24, and 48 hours after the initiation of hypoxia and normoxia conditions. A univariate variance analysis (pairwise least significant difference t test) using a SPSS 13.0 software package was performed to test for differences between different groups.
Results: PCR analysis of the chondrocytes showed that the expression of HIF-1α and VEGF mRNA increased at 12, 24, and 48 hours after induction of hypoxia. HIF-1α expression gradually increased throughout the study duration, while VEGF expression peaked at 12 hours. Compared to normoxia conditions, hypoxia resulted in constantly elevated expression levels of both. On the other hand, there was no significant difference in the ADAMTS-4 and TIMP-3 mRNA expression between hypoxic and normoxic conditions throughout the study (P > .05).
Conclusion: An upregulated HIF-1α and VEGF mRNA expression indicates their important roles in cartilage vascularization and development in newly hypoxic microenvironments. Additionally, chemically induced hypoxia has little effect on the expressions of ADAMTS-4 and TIMP-3.
Keywords: HIF-1α, VEGF, aggrecanase-1 (ADAMTS-4), TIMP-3, hypoxia, CoCl2, TMJ cartilage
Pages 277-279, Language: English
Concha bullosa is characterized by pneumatization of the middle turbinate and is one of the most common variations of the sinonasal anatomy. It is most often asymptomatic. A fungus ball in the concha bullosa is extremely rare, with only two reported cases in the English literature. This article describes a patient with such a fungus ball in the concha bullosa that caused right periorbital pain, specifically in the right medial canthal area, similar to mucosal contact point headache.
Keywords: concha bullosa, fungus ball, periorbital pain, referred pain
Pages 280-283, Language: English
Pages 284, Language: English
Pages 288-289, Language: English