Journal of Oral & Facial Pain and Headache, 01/2017

Painful posttraumatic trigeminal neuropathy (PPTTN) is a chronic condition that is difficult to endure and has a poorly understood pathophysiology. Treatment options are limited and often unsatisfactory due to insufficient efficacy and significant adverse effects. Botulinum toxin type A (BTX-A), initially used in the management of pathologically sustained or twisting muscular contractions, has recently been advocated for treatment of neuropathic pain. Its action is not limited to the blockage of acetylcholine release at the neuromuscular junction, but also includes inhibition of exocytosis of other neurotransmitters by interfering with the SNARE complexes of synaptic membranes. When injected into the painful location, the toxin can be taken up by peripheral terminals of nociceptive afferent nerve fibers, and this action suppresses peripheral and central release of algogenic neurotransmitters such as glutamate or substance P, thus promoting analgesia. Several randomized controlled trials in humans have provided emerging evidence for the therapeutic use of BTX-A in neuropathic pain states, including trigeminal neuralgia. This evidence, in addition to its good safety profile and long-lasting effect, suggests that BTX-A could be a potential novel treatment for PPTTN. Parole chiave: botulinum toxin, neuropathic pain, review, treatment, trigeminal

Aims: To address the two following questions: (1) What kind of somatosensory abnormalities may be characterized in patients receiving dental implants (IMP), in ongoing inflammatory dental pulpitis (IP) patients, and in neuropathic pain (atypical odontalgia [AO]) patients? and (2) What sort of sensory and neural changes may result from dental implant placement surgery and pulpectomy? Methods: A total of 60 subjects were divided into three groups: the IMP (n = 20), IP (n = 20), and AO groups (n = 20). Quantitative sensory testing (QST) was performed preoperatively (baseline) for all three groups and postoperatively at 1 month and 3 months after dental implant placement or pulpectomy (in the IMP group and IP group, respectively). Statistical analyses were completed with one-way and two-way analysis of variance and z score transformations (α = 5%). Results: The main findings of this study indicated that: (1) Elevations in mechanical detection threshold (MDT) and in current perception threshold (CPT) related to C-fiber activation, indicating a loss of function, were found at baseline in IP patients; (2) Somatosensory abnormalities such as allodynia, reduced MDT and mechanical pain threshold (MPT), and impaired pain modulation were found in AO patients; (3) No somatosensory alterations after implant placement were found in the IMP group; and (4) Somatosensory alterations in the form of reduction in the CPT related to C-fiber activation were reported 3 months after pulpectomy in the IP group. Conclusion: This study showed that somatosensory abnormalities were evident in AO and IP patients, and somatosensory alterations were seen in IP patients even 3 months after pulpectomy. However, no somatosensory alterations were seen after implant placement. Parole chiave: dental implants, dental pulp diseases, neuropathic pain, somatic pain, somatosensory disorders

Aims: To evaluate the prevalence of temporomandibular disorder (TMD) symptoms and their associations with alcohol consumption and smoking habits among young Finnish adults. Methods: The total sample consisted of 8,678 conscripts (8,530 men and 148 women, response rate 62.8%). Data on TMD symptoms, health behavior, and background/demographic factors were acquired by using a questionnaire. Self-reported facial pain and symptoms of TMD were used as outcome variables. The frequency of smoking and consumption of alcohol and snuff were used as explanatory variables. Chi-square tests, as expressed by odds ratios (OR) and 95% confidence intervals (95% CI), were used as statistical methods in the analysis. Statistical significance was determined at P .05. Results: The prevalence of different self-reported, at least occasional TMD symptoms varied between 5.8% (difficulty in jaw opening) and 27.8% (temporomandibular joint [TMJ] clicking) in the male population, with higher prevalences for all symptoms in the female population except for TMJ clicking. Smoking was significantly associated with TMD symptoms, except TMJ clicking. Consumption of alcohol at least once a week was associated significantly with facial pain, TMJ pain, TMJ pain at jaw rest, TMJ pain on jaw movement, and TMJ clicking. Use of snuff was associated significantly with facial pain. Conclusion: Daily smoking and increased frequency of alcohol consumption are associated with TMD symptoms among young Finnish adults. Dentists should be prepared to influence alcohol and tobacco consumption among young males to improve their health and quality of life. Parole chiave: alcohol, prevalence, smoking, temporomandibular disorders

Aims: To measure the prevalence of temporomandibular disorder (TMD) pain and examine its association with gender and other factors in an adult population in southern Sweden. Methods: In 2006, a questionnaire was sent to randomly selected individuals (n = 10,000) aged 20 to 89 years. Two specific questions were used to screen individuals with TMD pain, and an additional 16 questions were analyzed regarding the subjects' relation to TMD pain. The chi-squared test was used to compare the distribution of categorical variables, and factors possibly related to TMD pain were analyzed by using logistic regression models with a likelihood-ratio test. Results: The response rate was 63%. The prevalence of TMD pain (once a week or more) was 11.0% (95% confidence interval [CI]: 10.2% to 11.8%). Women reported experiencing TMD pain more frequently than men. Further, the prevalence of TMD pain increased significantly in adults 50 years of age. Those with TMD pain reported headaches much more frequently than those without TMD pain, and individuals with TMD pain self-reported poorer general health than those without it. Individuals with TMD pain also had higher scores on the oral health impact profile (OHIP-14). Moreover, the TMD pain group was three times more likely to have had a dentist or hygienist comment on their tooth wear than the non-TMD pain group. Conclusion: The prevalence of TMD pain in the adult population in southern Sweden was 11%. Factors related to TMD pain were female gender, age 50 years, headaches, self-reported poor general health, high scores on the OHIP-14, and tooth wear. Age was the only factor that showed a significant difference between genders for TMD pain. Parole chiave: adults, pain, prevalence, related factors, temporomandibular joint disorders

Aims: To investigate patients' experiences of therapeutic jaw exercises for treating masticatory myofascial pain. Methods: A total of 10 patients were selected for the interview study. All patients had received treatment with jaw exercises at a specialist clinic. Semi-structured interviews were conducted in a nonclinical environment according to an interview guide with 10 domains. The interviews were transcribed and translated into English. Systematic text condensation (STC) was used to arrange and analyze the text material. Results: In the systematic process of analyzing the qualitative data, four main themes were identified: "Patient Adherence," "Symptoms," "Treatment Effect," and "Participation." Most informants were initially skeptical of the jaw exercises due to their simplicity. Later on, the simplicity of the exercises and the fact that they did not need more advanced treatment were valued most by a majority of patients. Some informants suspected serious disease behind their symptoms. Treatment effects on pain and physical impairment were reported. To do the jaw exercises in conjunction with an already established routine seemed important to enhance adherence. Trust in the caregiver and being able to remedy their pain by themselves were also important to the informants. Conclusion: Jaw exercises are a useful treatment valued by patients due to their simplicity and effectiveness. However, before the treatment, patients should be informed about the cause of the symptoms, and any skepticism should be addressed. Results from this qualitative study cannot be generalized, but the study design and the selected population allow the results to be transferable to similar contexts. Parole chiave: dentistry, jaw exercises, physical treatment, systematic text condensation, temporomandibular disorders

Aims: To assess the association between chronic tension-type headache coexistent with chronic temporomandibular disorder (TMD) pain and severe limitations in physical and emotional functioning. Methods: Sample size estimation was used to determine that this case-control study should include 126 subjects. Subjects suffering from chronic TMD who were aged between 18 and 68 were recruited in routine clinical practice. Of the 126 included subjects, 63 had TMD pain associated with chronic tension-type headache (cases) and 63 had TMD pain without a history of tension-type headache (controls). Clinical diagnosis of TMD was made according to the Research Diagnostic Criteria for TMD (RDC/TMD) Axis I criteria, and clinical diagnosis of headache was made according to the International Classification of Headache (ICHD-II). RDC/TMD Axis II criteria were applied to record the scores from the Graded Chronic Pain Scale (GCPS) and the Symptoms Checklist-90-Revised Depression (SCL-DEP) and Somatization (SCL-SOM) scales. A logistic regression analysis was used to assess the relationship between TMD pain with chronic tension-type headache and high levels of depression and somatization severity as scored on the SCLDEP and SCL-SOM scales, respectively, and high pain-related disability (GCPS grade III or IV). Data were adjusted to take into account age, gender, time since TMD pain onset, chronic TMD pain intensity, and characteristic pain intensity. Results: The presence of chronic tension-type headache was significantly associated with severe SCL-DEP (odds ratio [OR] = 7.2; P .001), severe SCLSOM (OR = 13.8; P .001), and high pain-related disability (OR = 9.7; P .001). Conclusion: This study provides evidence of associations between the clinical diagnosis of chronic tension-type headache coexistent with chronic TMD pain and key aspects of physical and emotional functioning reflected in severe depression, severe somatization, and high pain-related disability. Parole chiave: depression, pain-related disability, somatization, temporomandibular disorders, tension-type headache

Aims: To conduct a pilot trial to test the feasibility of a guided self-help intervention for chronic orofacial pain. Methods: A pilot randomized controlled trial was conducted to compare the intervention with usual treatment. A total of 37 patients with chronic orofacial pain were randomized into either the intervention group (n = 19) or the usual treatment (control) group (n = 18). Validated outcome measures were used to measure the potential effectiveness of the intervention over a number of domains: physical and mental functioning (Short Form 36 [SF-36]); anxiety and depression (Hospital Anxiety and Depression Scale [HADS]); pain intensity and interference with life (Brief Pain Inventory [BPI]); disability (Manchester Orofacial Pain Disability Scale [MOPDS]); and illness behavior (Revised Illness Perceptions Questionnaire [IPQr]). Bootstrap confidence intervals were computed for the treatment effect (ES) posttreatment and at 3 months follow-up and adjusted for baseline values of the outcome measure by using analysis of covariance. Results: At posttreatment and the 3-month follow-up, 11 participants in the intervention group and 7 in the control group failed to complete outcome measures. The intervention was acceptable and could be feasibly delivered face to face or over the telephone. Although the pilot trial was not powered to draw conclusions about the effectiveness, it showed significant (P .05) effects of the intervention on physical and mental functioning and treatment control. Conclusion: The self-help intervention was acceptable to patients and allowed them to better understand and self-manage chronic orofacial pain. It showed potential effectiveness on outcome domains related to functioning and illness perception. Further research is needed to understand the cost effectiveness of the intervention for chronic orofacial pain. Parole chiave: behavioral, chronic orofacial pain, pilot trial, self-help intervention

Aims: To use a randomized, blinded, crossover design to evaluate the possible heterotopic effects of experimental periodontal ligament pain on adjacent gingival somatosensory sensitivity. Methods: A total of 12 healthy volunteers (8 female, 4 male; mean age ± standard error in means (SEM): 28 ± 1 years) participated in two randomized experimental quantitative sensory testing (QST) sessions, one in which capsaicin (experimental) was injected into the periodontal ligament and one in which isotonic saline (control) was injected. A total of 13 standardized QST measures were obtained on the buccal attached gingiva of a maxillary central incisor before, immediately after, and 30 minutes after injection of 30 μL of 5% capsaicin or isotonic saline into the periodontal ligament of the same incisor. The injection-evoked pain was evaluated on a 0-10 numeric rating scale (NRS). QST data were analyzed with two-way repeated measurement analysis of variance. Results: Capsaicin injected into the periodontal ligament evoked moderate levels of pain (mean peak NRS ± SEM: capsaicin: 5.5 ± .7; control: 0.6 ± 0.5 [P .001]). Capsaicin injected into the periodontal ligament significantly modulated gingival somatosensory sensitivity: increased sensitivity to warmth and painful heat stimuli occurred immediately and 30 minutes after the injection (P .025), whereas decreased sensitivity to both tactile and painful mechanical stimuli (P .011) occurred immediately after the injection and to painful mechanical stimuli only after 30 minutes (P = .016). No somatosensory changes were detected following the injection of isotonic saline (P > .050). Conclusion: Capsaicin injected into the periodontal ligament caused gain of heterotopic somatosensory sensitivity toward warmth and painful heat stimuli as well as reduction in mechanical sensitivity of the gingiva adjacent to the injected tooth. These findings may have implications for interpretation of somatosensory functions in patients with chronic intraoral pain, where gingival somatosensory profiles similar to those detected after capsaicin injection in the present study may be interpreted as signs of nerve damage. Parole chiave: capsaicin, intraoral QST, pain mechanisms, periodontal ligament, somatosensory

Aims: To investigate pain sensitivity by using quantitative sensory testing in older women with and without cervicogenic headache. Methods: A total of 18 older women (mean age ± standard deviation [SD] 64.28 ± 3.21 years) with cervicogenic headache and 17 healthy controls (65.18 ± 3.89 years) participated in the study. Pain thresholds (pressure, heat, and cold) and suprathreshold heat pain ratings (at 45°C, 47°C, and 49°C) were measured over the temporalis muscle, upper cervical spine, and tibialis anterior muscle. Analysis of variance was used to determine differences in pain outcomes between groups. Results: Compared to the control group, cold pain threshold in the cervicogenic headache patients was significantly decreased in the upper cervical region (P = .04) but not over the temporalis and tibialis anterior muscles (P > .05). There were no significant between-group differences in pressure pain threshold, heat pain threshold, or suprathreshold heat pain ratings at any sites (P > .05). Conclusion: Older women with cervicogenic headache have localized pain sensitivity to cold stimuli, suggesting peripheral mechanisms underlie the hyperalgesia. Parole chiave: cervicogenic headache, elderly, pain sensitivity, pain thresholds, suprathresholds

Aims: To test whether manipulation of mechanical pain sensitivity (MPS) of the masseter muscle is reflected in quantitative measures of entropy. Methods: In a randomized, single-blinded, placebo-controlled design, 20 healthy volunteers had glutamate, lidocaine, and isotonic saline injected into the masseter muscle. Self-assessed pain intensity on a numeric rating scale (NRS) was evaluated up to 10 minutes following the injection, and MPS was evaluated after application (at 5 minutes and 30 minutes) of three different forces (0.5 kg, 1 kg, and 2 kg) to 15 different sites of the masseter muscle. Finally, the entropy and center of gravity (COG) of the pain sensitivity scores were calculated. Analysis of variance was used to test differences in means of tested outcomes and Tukey post hoc tests were used to adjust for multiple comparisons. Results: The main findings were: (1) Compared with both lidocaine and isotonic saline, glutamate injections caused an increase in peak, duration, and area under the NRS pain curve (P .01); (2) A pressure of 2 kg caused the highest NRS pain scores (P .03) and entropy values (P .02); (3) Glutamate injections caused increases in entropy values when assessed with 0.5 kg and 1.0 kg but not with 2.0 kg of pressure; and (4) COG coordinates revealed differences between the x coordinates for time (P .01) and time and force for the y coordinates (P .01). Conclusion: These results suggest that manipulation of MPS of the masseter muscle with painful glutamate injections can increase the diversity of MPS, which is reflected in entropy measures. Entropy allows quantification of the diversity of MPS, which may be important in clinical assessment of pain states such as myofascial temporomandibular disorders. Parole chiave: entropy, mechanical sensitization, musculoskeletal pain, pain assessment, palpation