Edmond L. Truelove

Gender differences in pain modulation by diffuse noxious inhibitory controls: a systematic review.

&NA; Over the last decade, extensive research has demonstrated sex differences in pain perception and modulation. Several factors have been proposed to account for the differences observed between men and women, including pain modulation through diffuse noxious inhibitory controls (DNIC). Studies investigating sex differences in DNIC have shown mixed results, with some reporting decreased DNIC effect in women compared with men, while others found no difference in DNIC between the sexes. Additional studies have investigated DNIC in both sexes without focusing on sex differences. This systematic review aimed to answer the following question: “In humans of reproductive age without chronic pain, are women more likely than men to have decreased Diffuse Noxious Inhibitory Controls?” Relevant studies were identified by computerized searches of Pubmed/Medline, Embase, Biosis, Web of Science, PsycInfo and Cochrane (from January 1980 through February 2009). The search was limited to human studies with no language restriction. The initial search identified 718 titles and abstracts. Seventeen studies were included in the final stage and data regarding age and gender of participants, methodology and outcome measurements were extracted and analyzed. The majority of studies using pain report as the outcome found significantly more efficient DNIC in males than females (mean female/male ratio = 0.54). Studies evaluating pain thresholds and nociceptive flexion reflex indicated the opposite when simply averaged across studies; however, weighted analyses of threshold found more efficient DNIC in males. Gender differences in DNIC effect depend on both the experimental methodology and the modes of measurement of the effect.

Clinical Science Age-dependent Decreases in Human Submandibular Gland Flow Rates as Measured Under Resting and Post-stimulation Conditions

Submandibular saliva samples were obtained with a new collection device, under resting and post-stimulation conditions, from 28 healthy individuals between 70 and 91 years of age, and from 30 healthy individuals between 18 and 39 years of age. The salivary flow rates were significantly decreased in the aged group compared with the control group. The mean resting and post-stimulation flow rates for the aged group averaged 22% and 39%, respectively, of control values.

The roles of beliefs, catastrophizing, and coping in the functioning of patients with temporomandibular disorders

&NA; Pain‐related beliefs, catastrophizing, and coping have been shown to be associated with measures of physical and psychosocial functioning among patients with chronic musculoskeletal and rheumatologic pain. However, little is known about the relative importance of these process variables in the functioning of patients with temporomandibular disorders (TMD). To address this gap in the literature, self‐report measures of pain, beliefs, catastrophizing, coping, pain‐related activity interference, jaw activity limitations, and depression, as well as an objective measure of jaw opening impairment, were obtained from 118 patients at a TMD specialty clinic. Controlling for age, gender, and pain intensity, significant associations were found between (1) pain beliefs and activity interference, depression, and non‐masticatory jaw activity limitations, (2) catastrophizing and activity interference, depression, and non‐masticatory jaw activity limitations, and (3) coping and activity interference and depression. Controlling for age, gender, pain intensity, and the other process variables, significant associations were found between (1) beliefs and activity interference and depression, and (2) catastrophizing and depression. No process variable was associated significantly with the objective measure of jaw impairment. The results suggest that for patients with moderate or high levels of TMD pain and dysfunction, beliefs about pain play an important role in physical and psychosocial functioning.

Brief group cognitive-behavioral intervention for temporomandibular disorders

&NA; Temporomandibular disorders (TMD) are currently viewed as an interrelated set of clinical conditions presenting with signs and symptoms in masticatory and related muscles of the head and neck, and the soft tissue and bony components of the temporomandibular joint. Epidemiologie and clinical studies of TMD confirm its status as a chronic pain problem. In this report we present results from a randomized clinical trial which compared, at 3‐ and 12‐month follow‐ups, the effects of usual TMD treatment on TMD pain and related physical and psychological variables with the effects of a cognitive‐behavioral (CB) intervention delivered to small groups of patients before usual TMD treatment began. The purpose of this study was to determine whether a minimal CB intervention followed by dental TMD treatment enhanced the effects of usual clinical dental treatment. A second purpose of the study was to determine whether patients classified as high in somatization and psychosocial dysfunction would respond less favorably to this minimal intervention than would those low in somatization and dysfunction. Patients who participated in the CB intervention followed by usual treatment showed greater long‐term decreases in reported pain level and pain interference in daily activities than did patients who received only usual treatment. The benefits of CB intervention were not seen when the CB and UT groups were compared at 3‐month follow‐up. During the 3–12‐month follow‐up interval, however, the UT group maintained essentially the same level of improvement in characteristic pain while the CB group continued to improve, as hypothesized. During this same follow‐up interval, the CB group also showed a strong trend toward continued improvement in pain interference. Such effects were not observed for depression, somatization, or clinical measures of jaw range of motion. Additionally, as hypothesized, dysfunctional chronic pain patients did not appear to benefit from the brief CB intervention. Intent to treat analyses were also performed to assess generalizability of the results.

Comparison of clinical and magnetic resonance imaging diagnoses in patients with disk displacement in the temporomandibular joint

OBJECTIVE The purpose of this study was to validate the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) for the diagnostic subgroup of disk displacement with reduction, with magnetic resonance imaging used as a gold standard. STUDY DESIGN The diagnoses from the clinical examination of 78 joints in 39 patients, each with disk displacement with reduction in at least one TMJ, were compared with magnetic resonance imaging diagnoses. The readers of the magnetic resonance images were blinded to the clinical diagnoses. The data analysis included kappa statistics and calculation of predictive values. RESULTS The predictive value of the RDC/TMD for disk displacement with reduction was 0.65. For disk displacement alone-the movement of the disk on opening not being considered-the predictive value was 0.92. The diagnostic agreement between RDC/TMD and magnetic resonance imaging diagnoses for all joints examined was 53.8%. Most of the disagreement was due to false negative clinical diagnoses for asymptomatic joints. CONCLUSIONS A positive RDC/TMD examination is predictive for internal derangement but not reliable with regard to the type of disk displacement; such examination is therefore of limited value in determining the true disk position and its functional movements.

Effects of specific antibodies on the interaction between the fungus Candida albicans and human oral mucosa

Host-parasite interactions were studied in four groups: non-infected controls; infected carriers of Candida albicans without evidence of candidiasis; subjects with acute candidiasis; and subjects with chronic candidiasis. Specific anti-candida antibodies were demonstrated in saliva from subjects of all four groups; the titres reflected the degree of antigenic stimulation, being significantly higher in candidiasis than in controls or infected carriers. The adherence of C. albicans to buccal epithelial cells was not significantly different in a given saliva, regardless of whether the assay was carried out with autologous C. albicans and epithelial cells or with a stock strain in a standardized assay. Therefore, the standard assay was used to study the effects of specific salivary antibodies on adherence. A significant inverse correlation was found between salivary IgA anti-candida antibodies and the adherence of C. albicans to buccal epithelial cells, suggesting that IgA antibodies can inhibit adherence of candida to the oral mucosa. In some instances, removal of antibodies led to a significant increase in adherence; however, often this was not the case, indicating that some but not all of the antibodies present were capable of inhibiting the adherence of C. albicans to epithelial cells.

Differences in salivary flow rates in elderly subjects using xerostomatic medications

Stimulated whole salivary flow rate (SWSFR) was measured in a group of elderly subjects who were examined for the use of xerostomia-inducing medications. SWSFR was significantly reduced in elderly subjects using one of these medications when compared with control subjects (0.94 vs 1.52 ml/min). Increasing use of up to four different xerostomia-inducing medications did not result in additional significant reduction of stimulated salivary flow rate. Psychotropic and diuretic agents were the most commonly used xerostomatic medications, and these were almost equally potent in reducing mean flow rate (0.79 vs 0.84 ml/min). The use of potentially xerostomatic medications did not affect decayed, missing, or filled surface scores or unstimulated whole saliva pH values. A weak, statistically significant, positive correlation (r = 0.39, p less than 0.01) was found between subject age and salivary flow rate in this population of elderly subjects, and this suggests that SWSRF is influenced more by factors such as medication than by aging.

Oral mucosal lesions: Association with the presence of antibodies to the human immunodeficiency virus

To assess the relationship between oral lesions and antibodies to the human immunodeficiency virus, oral examinations of 803 homosexual males were conducted at the time of serologic testing. Nineteen percent were HIV seropositive. Thirty percent of antibody-positive subjects had one or more oral lesion(s), as compared with 7% of antibody-negative subjects (p less than 0.001). The presence of oral lesions was significantly associated with HIV seropositivity: a subject was 5.7 times as likely to have serum antibodies if he had one or more oral lesions (95% confidence interval, 3.5 to 9.1; p less than 0.001). This significant association with HIV seropositivity was only partially explained by cigarette smoking (adjusted odds ratio 3.1; 1.4-6.8; less than 0.006). Specific conditions that were significantly associated with seropositivity included candidiasis, hairy leukoplakia, periodontal disease, and Kaposis sarcoma. Other diseases identified included acute necrotizing ulcerative gingivitis, mucocutaneous ulcerations, and oral warts. Oral findings may occur earlier in the natural history of infection than previously reported.

Age-related Salivary Flow Rate Changes in Controls and Patients with Oral Lichen Planus

Unstimulated whole saliva and stimulated whole, parotid, and labial minor gland saliva samples were collected from 25 patients with oral lichen planus and from 25 age- and sex-matched controls between the ages of 25 and 87 years. All subjects did not smoke or chew tobacco, had no serious illnesses, and were unmedicated. There were no significant differences in flow rates between the two groups. However, a significant age-related decrease in labial minor gland saliva flow rate was found in both the lichen planus group and the controls. Flow rates of unstimulated and stimulated whole saliva and stimulated parotid saliva were not related to age in either group.

Relationship between orthodontic treatment, condylar position, and internal derangement in the temporomandibular joint

The purpose of this study was to test the hypothesis that retraction of maxillary front teeth may lock the mandible in a posterior position, and to evaluate any relationship between condylar position and signs and symptoms of internal derangements in the temporomandibular joint. A total of 29 female patients treated for Angle Class II, Division 1 malocclusion with extraction of maxillary first premolars and 34 female patients treated for Angle Class I malocclusion without tooth extraction consented to participate in a radiographic and clinical follow-up examination. The mean ages of the patients were 16.9 (SD 3.0) and 16.6 (SD 2.6) years, and the mean times after treatment were 1.6 (SD 1.0) and 1.5 (SD 0.9) years, respectively. Condylar position was measured in percent anterior and posterior displacement from absolute concentricity on lateral, central, and medial tomographic sections of each joint. Mean condylar position was more posterior at right central (P < 0.05) and medial (P < 0.01) tomographic sections in patients treated with extraction. The difference was due to a higher frequency of anteriorly positioned condyles in the nonextraction cases. No intergroup differences in the sagittal occlusal slide from CR to CO and the number of patients with clicking were found. However, the condyles were located more posteriorly in all tomographic sections (P < 0.05 for lateral, P < 0.001 for central and medial) in patients with clicking than in those without.The purpose of this study was to test the hypothesis that retraction of maxillary front teeth may lock the mandible in a posterior position, and to evaluate any relationship between condylar position and signs and symptoms of internal derangements in the temporomandibular joint. A total of 29 female patients treated for Angle Class II, Division 1 malocclusion with extraction of maxillary first premolars and 34 female patients treated for Angle Class I malocclusion without tooth extraction consented to participate in a radiographic and clinical follow-up examination. The mean ages of the patients were 16.9 (SD 3.0) and 16.6 (SD 2.6) years, and the mean times after treatment were 1.6 (SD 1.0) and 1.5 (SD 0.9) years, respectively. Condylar position was measured in percent anterior and posterior displacement from absolute concentricity on lateral, central, and medial tomographic sections of each joint. Mean condylar position was more posterior at right central (P less than 0.05) and medial (P less than 0.01) tomographic sections in patients treated with extraction. The difference was due to a higher frequency of anteriorly positioned condyles in the nonextraction cases. No intergroup differences in the sagittal occlusal slide from CR to CO and the number of patients with clicking were found. However, the condyles were located more posteriorly in all tomographic sections (P less than 0.05 for lateral, P less than 0.001 for central and medial) in patients with clicking than in those without.