Journal of Oral & Facial Pain and Headache, 03/2013

Aims: To assess the influence of occlusal stabilization splints on sleep-related respiratory variables in obstructive sleep apnea (OSA) patients. Methods: Ten OSA patients (47.3 ± 11.7 years of age) received a stabilization splint in the maxilla. All patients underwent three polysomnographic recordings with their splint in situ, and three recordings without their splint in situ, using a randomized crossover design. Results: Repeated-measures ANOVAs did not yield statistically significant differences in the Apnea-Hypopnea Index (AHI) or in the Epworth Sleepiness Scale (ESS), neither between the three nights without the stabilization splint (AHI: F = 2.757, P = .090; ESS: F = 0.153, P = .860) nor between the nights with the splint in situ (AHI: F = 0.815, P = .458; ESS: F = 0.231, P =. 796). However, independent ANOVAs revealed that the mean AHI of the three nights with the stabilization splint in situ (17.4 ± 7.0 events/ hour) was significantly higher than that of the nights without the splint in situ (15.9 ± 6.4 events/hour) (F = 7.203, P = .025). The mean increase in AHI with the splint in situ was 1.4 ± 1.7 (95% confidence interval = -1.9-4.7). No difference in ESS was found when both conditions were compared (F = 1.000, P = .343). Conclusion: The use of an occlusal stabilization splint is associated with a risk of aggravation of OSA; however, the effect size was small, which reduces the clinical relevance of the study. Keywords: crossover design, obstructive sleep apnea, occlusal stabilization splint, randomized controlled trial, vertical dimension

Aims: To investigate cerebral cortical changes by using functional magnetic resonance imaging (fMRI) after denture renewal and to test how these relate to prosthodontic treatment adaptability as measured by chewing efficiency and maximum bite force. Methods: Ten complete denture wearers (five women and five men, mean age ± standard deviation: 70.3 ± 9.1 years) participated in the study. Each had their complete dentures renewed and underwent an fMRI examination with three functional tasks (lip pursing; jaw tapping; jaw clenching) as well as a color-mixing test for chewing efficiency and unilateral maximum bite force measurements. Recordings were performed with the old dentures (T0) and with the new dentures on insertion (T1) and at 1 week (T2) and 3 months postinsertion (T3). At T1, denture stability and retention (S/T) were assessed by two independent operators. Wilcoxon signed rank tests and Spearman's rho correlation were carried out for data analysis. Results: The right and the left precentral gyrus (PRCG) and postcentral gyrus (POCG) were identified with significant activation across all three functional tasks. A statistically significant increase in the level of activity between T0 and T2 (POCG: P = .022; PRCG: P = .017) was found during jaw clenching tasks. Both regions of interest (PRCG, POCG) appeared to correlate with S/T of the new dentures while the subject performed a lip-pursing task (PRCG: r = 0.689, P = .027; POCG: r = 0.665, P = .036). The chewing efficiency and maximum bite force increased significantly during the adaptation to replacement dentures (chewing efficiency: T1-T2 P = .032, T2-T3 P = .012; maximum bite force right side: T2-T3 P = .047). Conclusion: Changes in brain activity occurred in the adaptation to replacement dentures and appeared to regain preinsertion activity levels during motor tasks involving the dental occlusion after 3 months postinsertion. Keywords: bite force, chewing efficiency, complete denture, fMRI, neuroplasticity

Aims: To assess, by systematic review of the literature, (1) the prevalence and incidence of temporomandibular disorder (TMD) pain after whiplash trauma, and (2) whether treatment modalities commonly used for TMD are equally effective in patients with solely TMD pain and those with TMD/whiplash-associated disorders (WAD) pain. Methods: A systematic literature search of the PubMed, Cochrane Library, and Bandolier databases was conducted from January 1966 through October 2012. The systematic search identified 125 articles. After an initial screening of abstracts, 45 articles were reviewed in full text. Two investigators evaluated the methodological quality of each identified study. Results: Eight studies on prevalence/incidence of TMD pain in WAD and four studies on interventions in TMD pain and WAD met the inclusion criteria. The reported median prevalence of TMD pain after whiplash trauma was 23% (range 2.4% to 52%) and the incidence ranged from 4% to 34%. For healthy controls, the reported median prevalence was 3% (range 2.5% to 8%) and the incidence ranged from 4.7% to 7%. For patients with a combination of TMD pain and WAD, treatment modalities conventionally used for TMD, such as jaw exercises and occlusal splints, had less of an effect (median improvement rate of 48%, range 13% to 68%) compared to TMD patients without a whiplash injury (75%, range 51% to 91%). Conclusion: There is some evidence that prevalence and incidence of TMD pain is increased after whiplash trauma. The poorer treatment outcome suggests that TMD pain after whiplash trauma has a different pathophysiology compared to TMD pain localized to the facial region. Keywords: jaw, neck, systematic review, temporomandibular disorders, whiplash injuries

Aims: To assess possible differences between care seekers and non-care seekers with temporomandibular disorder (TMD) pain complaints, by using semi-structured interviews. Methods: Semi-structured interviews were held with 16 subjects who had TMD- pain complaints: 8 care seekers and 8 non-care seekers, matched for age, sex, pain intensity, and fear of movement. Subjects were selected from a previously held survey study, with their consent. The interviews were audiotaped, transcribed verbatim, and analyzed according to qualitative content analysis. Results: From the analysis, seven themes differentiating care seekers from non-care seekers were identified: catastrophizing, pain management, assertiveness, critical attitude towards health care, confidence in medical care, recognition, and adequate referral. Conclusion: Aspects upon which care seekers differed from non-care seekers were mainly person-related characteristics. Next to these characteristics, it appeared that inadequate referrals may play a role in care seeking. The use of semi-structured interviews may further improve insights into processes that determine care seeking among people with TMD pain complaints. Keywords: care seeking, health care practitioners, qualitative research, semi-structured interviews, temporo-disorder pain

Aims: To test the validity of the use of the Douleur Neuropathique en 4 Questions (DN4) questionnaire for burning mouth sydrome (BMS) patients, and to differentiate patients by measuring the time course of the pain in BMS patients over a period of 7 days with a visual analog scale (VAS). Methods: Patients completed the DN4 questionnaire and a VAS every hour for 7 days. The data were expressed as mean ± SEM. Correlations were searched using the Spearman correlation test with a significance level at P .05. Results: Data were fully analyzed for the 22 patients (21 females, 1 male, mean [± SEM] age 62.7 ± 2.3 years) for the DN4 and 17 patients for the VAS. DN4 scores ranged from 2 to 7 (mean score: 3.9 ± 0.3), and 59% of the patients had a DN4 score >= 4. Burning was found in all the patients, followed by pricking pain (pins and needles) and allodynia (pain on brushing) (both 68%), tingling (45%), numbness (32%), itching (27%), and electrical discharges (23%). Monitoring the hourly time-course of the pain led to the identification of two groups with intermittent or constant pain. In the latter, averaging the VAS for 7 days enabled plotting a curve, the slope of which could be calculated. The range of the slopes was 0.00 to 0.59, and a regular increase of pain during the day was seen for the majority of the patients. Conclusion: The findings support the use of DN4 as a tool for screening BMS and reinforce the view that BMS is a clinical manifestation of a neuropathic disease. The methodology of this study can be used for a better description of the patients and the identification of subgroups. Keywords: burning mouth syndrome, DN4, pain, visual analog scale

Aims: To investigate in a randomized, double-blinded, placebocontrolled, crossover study the effect of a single dose of the nonselective ß-adrenergic receptor antagonist propranolol (40 mg) on hypertonic saline (HS)-evoked masseter muscle pain and autonomic activity during rest and during a mental arithmetic task (Paced Auditory Serial Addition Task, PASAT). Methods: Sixteen healthy women participated in two sessions in which propranolol or placebo was administered orally prior to two 5-minute infusions (30 minutes apart) of HS in the masseter muscle. The second HS infusion was combined with PASAT. HS-evoked pain intensity was scored on a numeric rating scale (NRS, 0 to 10). Heart rate variability and hemodynamic measures were recorded noninvasively (Task Force Monitor). Data were analyzed with repeated measurements analysis of variance (ANOVA). Results: Propranolol did not reduce NRS pain scores compared with placebo but did induce significant autonomic changes with reduced heart rate and increased heart rate variability (standard deviations of all normal RR intervals; root mean square successive differences; low-frequency power; high-frequency power; and total power) independent of the mental task. Conclusion: A single dose of propranolol had no effect on acute HS-evoked pain levels during rest or during mental arousal. However, it influenced the tone of the autonomic nervous system, possibly reflecting an anxiolytic effect. Keywords: autonomic nervous system, experimental muscle pain, mental arithmetic task, propranolol, trigeminal nociceptio

Aims: To assess the effects of intra-alveolar application of chlorhexidine gel on the incidence of alveolar osteitis (dry socket) and the severity of postsurgical pain. Methods: A total of 160 impacted mandibular third molars were extracted in 80 patients enrolled in this trial. In each subject, a socket was randomly selected and packed to the crest of the alveolar ridge with a gelatin sponge dressing saturated in 0.2% chlorhexidine gel. The contralateral socket was packed with a dry dressing as the placebo. None of the included patients took antibiotics or analgesics. The occurrence of dry socket and patients' pain levels were assessed at the first and third postoperative days. The data were analyzed using Spearman correlation coefficient, McNemar, Wilcoxon, and chi-square tests. Results: Chlorhexidine gel significantly reduced dry socket incidence from 32.6% to 11.3% (P = .001 [McNemar and chi-square], absolute risk reduction = 21.2%, relative risk reduction = 65.4%, odds ratio = 0.263, relative risk = 0.345). It also significantly relieved postoperative pain on both sides in all the patients (P = .001 [Wilcoxon]) and also in the 54 subjects who did not develop dry socket (P = .001 [Wilcoxon]). Conclusions: Besides decreasing the incidence of dry socket, chlorhexidine gel can reduce postsurgical pain in patients with and without dry socket. Keywords: alveolar osteitis, chlorhexidine, dry socket, impacted teeth, postoperative pain, third molars, tooth extraction

Aims: To investigate thermal thresholds of selected orofacial sites, determine if there is a relationship between thermal thresholds at each site, and analyze the influence of two different baseline temperatures on thermal thresholds at the tongue tip. Methods: Thirty healthy men (mean age, 26 years) participated. Cold detection (CDT), warm detection (WDT), cold pain (CPT), and heat pain (HPT) thresholds were measured bilaterally at five orofacial sites (mentum, lower lip, cheek, forehead, and tongue tip). Relations between thermal thresholds at each test site were assessed. Thermal sensitivity of the tongue tip was compared at two different baseline temperatures (32˚C and 36˚C). One-way ANOVA, Turkey post-hoc test, paired t test and Pearson's correlation were used for statistical analyses. Results: There was a significant difference for CDT, WDT, and HPT between test sites (ANOVA, P .001) but no significant difference for CPT (P = .634). Subjects sensitive to cooling were sensitive to warming at the mentum (r = 0.379), tongue tip (r = 0.610), and cheek (r = 0.431) but not at the other test sites. There was a strong negative correlation between CPT and HPT at all test sites. There was no significant difference for CDT and WDT at the baseline temperature of 36˚C (paired t test, P =.660), but there was a significant difference at the baseline temperature of 32˚C (P .001). There were no significant differences between CPTs at the two different baseline temperatures (P =.773), while a significant difference existed between HPTs (P = .034). Conclusion: Thermal thresholds varied between the orofacial test sites, and baseline temperature affected thermal sensitivity of the tongue. Subjects who were relatively sensitive to cold tended to be more sensitive to heat. Keywords: baseline temperature, orofacial, quantitative sensory testing, thermal thresholds, trigeminal site

Aims: To translate the Pictorial Representation of Illness and Self Measure (PRISM) instrument from German to Portuguese (Brazilian) and adapt it to the Brazilian cultural context, and then assess its reliability and validity in orofacial pain patients. Methods: The PRISM was translated to Portuguese then back-translated to German. The translated PRISM was evaluated by a multidisciplinary committee and administered as a pre-test to 30 Portuguese-speaking orofacial pain patients. Psychometric properties were obtained after testing 116 orofacial pain patients. Validity was obtained through correlation analyses of scores obtained from PRISM and other psychometric tests, including the Numerical Pain Scale (NPS), Insomnia Severity Index (ISI), and Hospital Anxiety and Depression Scale (HAD). Results: The adapted instrument showed high levels of reliability, proven by means of the test-retest procedure, and calculation of the Intraclass Correlation Coefficient (ICC = 0.991). Significant correlations were found between PRISM and the other tests. Correlation with NPS was moderate (-0.42), whereas correlations with ISI (-0.24), HAD-anxiety (-0.25), and HAD-depression (-0.22) were weak. Conclusion: The cross-cultural adaptation process of PRISM was successful and the adapted version offers reliable and valid psychometric properties in the Brazilian context. Keywords: cultural adaptation, orofacial pain, Pictorial r epresentation of i llness and Self Measure, P ri SM, reliability, suffering, validation studies