Time-course of pain and salivary opiorphin release in response to oral capsaicin differ in burning mouth syndrome patients, temporomandibular disorders patients and control subjects

OBJECTIVES

Opiorphin is an analgesic peptide released by salivary glands and capsaicin an agonist of TRPV1 receptors eliciting burning sensations. The primary objective of this study was to assess opiorphin release after stimulation of the tongue by capsaicin (STC). The secondary objectives were to compare opiorphin release after STC in 3 groups of subjects [healthy (CTRL), Burning Mouth Syndrome (BMS), painful Temporomandibular disorders (TMDp)] and pain evoked by STC in these 3 groups.

MATERIALS AND METHODS

Salivary opiorphin was assessed with high-performance liquid chromatography at 3 different time points (baseline, after 5 min and 20 min of STC). Pain was self-reported on a (0-10) numeric rating scale.

RESULTS

Three groups (N = 16) of adults were recruited at the Clinical Hospital Centre and School of Dental Medicine in Zagreb. Opiorphin levels were higher (1) in TMDp compared to CTRL in 1st (2.23 ± 1.72 pg/ul vs. 0.67 ± 0.44 pg/ul, p = 0.002) and 3rd sampling (2.44 ± 2.01 pg/ul vs. 0.74 ± 0.52 pg/ul, p = 0.020) and (2) within BMS group at 3rd sampling vs. baseline (p < 0.025). Pain scores were higher in BMS compared to TMDp (p < 0.025) and CTRL (p < 0.025).

CONCLUSION

This study evidenced (1) a differential basal amount of opiorphin in two pain conditions and control subjects (2) a differential kinetic of release of opiorphin after STC in CTRL, BMS and TMDp (3) a differential pain perception after STC in BMS and TMDp vs. CTRL, which can provide a readout for animal models.

CLINICAL RELEVANCE

The specific regulation of opiorphin release in patients with orofacial painful conditions provides valuable insights for clinicians and researchers in physiology and pathology and encourages further research in this area.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04694274. Registered on 01/05/2021.

Pain sensitivity and quality of life of patients with burning mouth syndrome: a preliminary study in a Chinese population

BACKGROUND

Burning mouth syndrome (BMS) is an oral-facial pain disorder involving the central and peripheral nervous systems, but the evidence for altered pain sensitivity remains inconclusive. The aim of this study was to investigate pain sensitivity and oral health-related quality of life (OHRQoL) in patients with BMS and to assess the relationship between them.

METHODS

Fifty Chinese patients with BMS (57.82 ± 11.2 years) and fifty age- and gender-matched healthy subjects (55.64 ± 10.1 years) participated in the study. The Pain Sensitivity Questionnaire (PSQ) was used to assess participants' pain sensitivity. The Oral Health Impact Profile (OHIP-14) was used to evaluate participants' OHRQoL.

RESULTS

The PSQ total score (p = 0.009), the PSQ minor score (p = 0.003) and the OHIP-14 score (p<0.05) of patients with BMS were significantly higher than those of the healthy subjects. Simple linear regression showed that the PSQ minor score was significantly associated with the OHIP-14 score in patients with BMS (β = 0.338, p = 0.016).

CONCLUSION

Patients with BMS have higher pain sensitivity than healthy subjects. Reducing pain sensitivity might help to improve the quality of life of patients with BMS.

The social context of burning mouth syndrome: an exploratory pilot study of stigma, discrimination, and pain

BACKGROUND

The social context of burning mouth syndrome (BMS) has received little attention in the scientific literature. However, social psychological theory and insights from those with lived experiences suggest that people living with BMS experience compounding effects of stigma related to their pain, diagnosis (or lack thereof), and intersectional identities.

OBJECTIVE

Our aim is to provide initial evidence and to motivate new directions for research on BMS. Here, we present the results of an exploratory pilot study (n = 16) of women living with BMS in the United States.

METHODS

Participants completed self-report measures of stigma, discrimination, and pain, as well as laboratory assessments of pain through quantitative sensory testing.

RESULTS

Results indicate a high prevalence of internalized BMS stigma, experience of BMS-related discrimination from clinicians, and gender stigma consciousness in this population. Moreover, results provide initial evidence that these experiences are related to pain outcomes. The most robust pattern of findings is that internalized BMS stigma was related to greater clinical pain severity, interference, intensity, and unpleasantness.

CONCLUSION

Given the prevalence and pain-relevance of intersectional stigma and discrimination identified in this pilot study, lived experience and social context should be incorporated into future research on BMS.

Salivary biomarkers in burning mouth syndrome: A systematic review and meta-analysis

The objective of this systematic review was to evaluate which salivary biomarkers are altered in patients with burning mouth syndrome (BMS) compared to a control group (CG). A comprehensive literature search was conducted in four databases. Case-control studies evaluating salivary biomarkers in BMS patients were included. Risk of bias was assessed using the Newcastle-Ottawa tool. RevMan was used for meta-analysis. Seventeen studies were selected. The included studies collected 54 different biomarkers. Of these biomarkers, only three (cortisol, α-amylase, and dehydroepiandrosterone) were analyzed in three or more studies. Dehydroepiandrosterone obtained contradictory results among the studies. However, cortisol and α-amylase levels were found to be higher in BMS patients. Cortisol was the only biomarker which could be included for meta-analysis. Cortisol levels were significantly higher in the BMS group compared to the CG (Mean Difference = 0.39; 95% CI [0.14-0.65]; p = 0.003). In conclusion, different studies investigated salivary biomarkers in patients with BMS compared to a CG, with controversial results. Meta-analysis, confirmed by trial-sequential analysis, showed how cortisol levels were significantly higher in BMS. Cortisol emerges as an interesting salivary biomarker in BMS, but future properly designed studies are needed to evaluate its role in diagnosis and/or response to treatment.

Salivary metabolome indicates a shift in tyrosine metabolism in patients with burning mouth syndrome: a prospective case-control study

ABSTRACT

The pathophysiology of primary burning mouth syndrome (BMS) remains controversial. Targeted analyses or "omics" approach of saliva provide diagnostic or pathophysiological biomarkers. This pilot study's primary objective was to explore the pathophysiology of BMS through a comparative analysis of the salivary metabolome among 26 BMS female cases and 25 age- and sex-matched control subjects. Secondary objectives included comparative analyses of inflammatory cytokines, neuroinflammatory markers, and steroid hormones among cases and control subjects, and among BMS patients according to their clinical characteristics. Salivary metabolome, neuroinflammatory markers, cytokines, and steroids were, respectively, analysed by liquid chromatography coupled with mass spectrometry, ELISA and protease activity assay, and multiparametric Luminex method. Among the 166 detected metabolites, univariate analysis did not find any discriminant metabolite between groups. Supervised multivariate analysis divided patients into 2 groups with an accuracy of 60% but did not allow significant discrimination (permutation test, P = 0.35). Among the metabolites contributing to the model, 3 belonging to the tyrosine pathway ( l -dopa, l -tyrosine, and tyramine) were involved in the discrimination between cases and control subjects, and among BMS patients according to their levels of pain. Among the detectable molecules, levels of cytokines, steroid hormones, and neuroinflammatory markers did not differ between cases and control subjects and were not associated with characteristics of BMS patients. These results do not support the involvement of steroid hormones, inflammatory cytokines, or inflammatory neurogenic mediators in the pathophysiology of pain in BMS, whereas the observed shift in tyrosine metabolism may indicate an adaptative response to chronic pain or an impaired dopaminergic transmission.

Sexual desire, mood disorders and sleep disturbances in female BMS patients: A controlled study

BACKGROUND

Burning mouth syndrome is a chronic orofacial pain with intraoral burning and other oral dysaesthetic symptoms that significantly affects the quality of life. The aim of this study is to evaluate the sexual desire in women with BMS and to investigate the possible related factors.

METHODS

A case-control study was performed. BMS patients were enrolled according to the International Classification of OroFacial Pain criteria. Demographic variables were collected. We evaluated pain with the Numeric Rating Scale (NRS), Visual Analogue Scale (VAS) and Total Pain Rating Index (T-PRI), anxiety and depression using the Hospital Anxiety and Depression Scale (HADS-A e HADS-D), sleep disturbances with Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS), and sexual desire using Sexual Desire Inventory (SDI).

RESULTS

A total of 50 BMS women and 50 healthy controls were enrolled. Compared with the controls, the BMS patients showed higher scores in the NRS (7,81 ± 1,71 vs. 0,14 ± 0.40; p < 0.0001), TPR-I (10,50 ± 4,86 vs. 0,36 ± 1,06; p < 0.0001), HADS-A (11,86 ± 2,85 vs. 3,90 ± 2,81; p < 0.0001), HADS-D (8,04 ± 3,18 vs. 1,42 ± 1,86; p < 0.0001) and PSQI (9,04 ± 2,62 vs. 4,64 ± 3,27; p < 0.0001). The mean SDI in the study group was significantly lower compared to healthy controls (32,36 ± 14,45 vs. 69,70 ± 19,94; p < 0.0001). No correlation was found between SDI and others items explored.

CONCLUSION

In line with previous studies, anxiety, depression and sleep disturbances are more common in BMS patients than in healthy population. This pilot study demonstrates for the first time an association between BMS and low sexual desire.

Association Between Anxiety and Descending Pain Modulation of Thermal Stimuli in Patients with Burning Mouth Syndrome: A Cross-Sectional Study

AIMS

To investigate the predictive power of depression and anxiety for conditioned pain modulation (CPM) and to examine the relationships of CPM at 40°C and CPM at 47°C with age, disease-related pain, pain duration, and psychosocial factors in burning mouth syndrome (BMS).

METHODS

A total of 22 patients with BMS and 22 healthy female controls participated in this study. Temporal summation was used as the test stimulus for CPM, and subsequent exposure either to a nonpainful (40°C) or a painful (47°C) Peltier thermode was used as the conditioning stimulus. CPM was calculated as the difference in pain perception following the conditioning stimulus. Psychosocial factors were examined using the Profile of Mood States (POMS) and the State-Trait Anxiety Inventory (STAI).

RESULTS

State anxiety and tension-anxiety scores were significantly higher for patients with BMS than for control participants. Multiple regression analyses showed that CPM47°C was affected by vigor, fatigue, confusion, and trait anxiety (adjusted R2 = 0.685, F = 5.147, P = .098). The corresponding analysis for CPM40°C showed that the model was not predictive for the following variables: disease-related pain, pain duration, or components of the POMS or STAI. A significant positive correlation was found between CPM47°C and trait anxiety, suggesting that trait anxiety negatively affected the endogenous pain modulation system.

CONCLUSION

Increases in trait anxiety reduced the CPM effect. These findings suggest that CPM impairments and increases in trait anxiety are involved in the development of BMS.

[Oral hygiene and microcirculation of the mucous membrane of the tongue and gums dynamics in patients with burning mouth syndrome as a result of the use of a toothbrush with a gold-zinc electroplating]

THE AIM OF THE STUDY

Was to assess the level of oral hygiene and microcirculation of the mucous membrane of the tongue and gums in patients with burning mouth syndrome (BMS) as a result of using a toothbrush with a gold-zinc electroplating.

MATERIALS AND METHOS

The study included 50 patients of both sexes aged 45-64 years with the diagnosis of BMS divided into two groups. In the main group, the complex of hygienic measures included the use of a toothbrush with a gold-zinc electroplating and a paste with the fluorine content of 1350 ppm. In the comparison group, a regular manual toothbrush and a paste with a fluoride content of 1350 ppm were used for oral hygiene. A control group consisted of 25 healthy people with the mean age of 44±4.5 years without clinical signs of BMS in the oral cavity and concomitant acute somatic pathologies.

RESULTS

Tongue mucosa microcirculation level in patients using the toothbrush with a gold-zinc electroplating was significantly higher than in the comparison group using conventional manual toothbrush. Oral hygiene level assessment showed statistically significant better brushing efficacy in patients using the toothbrush with a gold-zinc electroplating.

CONCLUSION

The use of a toothbrush with a gold-zinc electroplating contributes to the normalization of microcirculation in the mucous membrane of the tongue and gums and is recommended for inclusion in the complex of therapeutic measures in patients with BMS.

Multifactor analysis of patients with oral sensory complaints in a case-control study

BACKGROUND

There are an increasing number of patients with oral sensory complaints (OSCs) presenting to our dental clinic. For most dentists, it is difficult to distinguish burning mouth syndrome (BMS) from other oral mucosal diseases that may cause symptoms such as burning mouth. It is beneficial to effectively distinguish OSC patients to reduce misdiagnosis and eliminate burning symptoms as much as possible.

METHODS

Patients with oral burning sensations in the oral mucosal disease clinic were collected from the Peking University Hospital of Stomatology between September 1, 2014 and December 31, 2018. After excluding oral candidiasis, anemic stomatitis, dental material allergy, and other diseases from patients with oral sensory complaints, basic conditions such as gender, age, education level, job status, hyperglycemia, hypertension, hyperlipidemia, history of brain abnormalities, history of cervical spondylitis, history of thyroid disease, history of thyroid disease and insomnia were obtained. The BMS patients were compared with the control group. The t test and Chi-square test were used for statistical analysis to compare the clinical symptoms of these diseases and explore the risk factors for BMS.

RESULTS

In this case-control study, 395 patients (321 females and 74 males, mean age 55.26 ± 10.51 years) with oral sensory complaints and 391 healthy controls (281 females and 110 males, mean age 47.11 ± 13.10 years) were enrolled, among which, 8.4% (33/395) had oral candidiasis, 1.3% (5/395) had dental material allergy, 0.8% (3/395) had anemic stomatitis and 0.5% (2/395) had lichen planus. A total of 352 patients were eventually diagnosed with BMS. Anxiety and depression were more severe in BMS patients, as were the incidences of sleep disorders and brain abnormalities. Logistic regression analysis showed that age (odds ratio [OR] = 2.79, 95% confidence interval [CI]: 1.61-4.83, P < 0.001), total cholesterol level (OR = 2.92, 95% CI: 1.32-6.50, P = 0.009) and anxiety score (OR = 1.75, 95% CI: 1.01-2.77, P = 0.017) significantly increased the incidence of BMS. Patients with hyperglycemia (OR = 0.46, 95% CI: 0.23-0.89, P = 0.022), low body mass index (BMI: OR = 0.57, 95% CI: 0.34-0.93, P = 0.026) and low education level (OR = 3.43, 95% CI: 1.91-6.15, P < 0.001) were more likely to suffer from BMS.

CONCLUSIONS

Oral candidiasis, anemic stomatitis, and dental material allergy with burning symptoms should be excluded from patients with BMS. It is recommended to conduct a questionnaire survey (including anxiety and depression), blood cell analysis, and salivary fungus culture for all patients with an oral burning sensation. It is necessary to conduct a patch test on patients with oral burning sensations and metal restorations.

Taste and Pain Response in Burning Mouth Syndrome With and Without Geographic Tongue

AIMS

To assess the effect of geographic tongue (GT) on taste, salivary flow, and pain characteristics in burning mouth syndrome (BMS) to determine whether GT is a contributing factor to BMS and whether BMS and GT represent similar patient populations.

METHODS

A retrospective chart study was conducted. Patients with a diagnosis of BMS or BMS/GT were included. Data regarding smell testing, spatial taste-testing, salivary flow, oral pH, and subjective pain rating on a generalized labeled magnitude scale (gLMS) were collected.

RESULTS

No significant differences in age, gender, oral pH, smell, or pain were found between groups. Stimulated and unstimulated salivary flow were significantly lower in BMS/GT. Taste responses to all taste stimuli and to ethanol were significantly lower in BMS, with the exception of sour at the fungiform papillae.

CONCLUSION

BMS and BMS/GT present with similar clinical pain phenotype and demographics; however, taste was more intact in BMS/GT, suggesting that GT may be a contributing factor in the development of BMS through a mechanism that does not involve taste.

Are pharmacological treatments for oro-facial pain effective?

Data sourcesElectronic searches of PubMed, the Cochrane Library, Embase, the National Health Service Economic Evaluation Database and HTA until March 2017. Also handsearched referenced in the original articles. Grey literature was not included.Study selectionRandomised controlled trials with more than ten participants with oro-facial pain duration of more than three months were sub grouped into: TMD-muscle pain (TMD-m), TMD-joint pain (TMD-j), burning mouth syndrome (BMS) and other oro-facial pain. Studies include any pharmacological treatment against another pharmacological, non-pharmacological treatment, placebo or no treatment. The primary outcome was change in pain intensity and the secondary outcome was the effect on quality of life.Data extraction and synthesisThree authors formed three review pairs that independently checked for inclusion. Four pairs of reviewers independently evaluated the risk of bias using the Swedish Agency for Health Technology Assessment and Assessment of Social Services tool. Two authors independently extracted data that were later assessed according to a modified GRADE system.ResultsForty-one studies, rated medium to low risk of bias, were included in qualitative analysis on patients with TMD-j pain (15 studies, n = 790), TMD-m pain (nine studies, n = 375), BMS (17 studies n = 868). For the TMD-j group five studies support NSAIDs and nine corticosteroid and hyaluronate injections. Eight of the nine TMD-m studies were included in a network meta-analysis (NMA), they support cyclobenzaprine, botulinum toxin injections and topical treatment with Ping-On ointment. Five of the 17 BMS studies included in a NMA support topical capsaicin and clonazepam. Of the remaining 12, five showed no effect while the remaining support alpha lipoic acid, gabapentin, clonazepam, amisulpride and SSRIs.ConclusionsBased on the results of the NMA the authors concluded that clonazepam and capsaicin are effective for BMS while cyclobenzaprine, a muscle relaxant, has a positive treatment effect on TMJ-m. Evidence from the narrative synthesis suggests NSAIDs, corticosteroid and hyaluronate injections are effective for TMD-j pain.

Not only limbs in atypical restless legs syndrome

Restless legs syndrome (RLS) typically affects the limbs, but the involvement of other body parts has also been reported. In this essay, we critically review all literature reports of atypical RLS cases with unusual localizations. Applying the updated diagnostic criteria of the International restless legs syndrome study group (IRLSSG), which also consider symptoms localized outside of the lower limbs, a few of these atypical cases reported in the previous literature resulted in a definitive diagnosis of RLS. We also discuss the relationship between RLS and burning mouth syndrome (BMS) or restless genital syndrome (RGS). We conclude clinical sleep specialists should be aware of unusual RLS localizations because they respond to the usual treatment for RLS. All the IRLSSG diagnostic criteria should be applied in every suspected case, in order to establish a correct diagnosis of this disabling but treatable condition.

Burning mouth and saliva

Stomatodynia is the complaint of burning, tickling or itching of the oral cavity, and can be associated with other oral and non-oral signs and symptoms. However, the oral mucosa often appears normal, with no apparent underlying organic cause to account for the symptomatology. The etiology is unknown, though evidence points to the participation of numerous local, systemic and psychological factors. Among the local factors, saliva may play an important role in the symptoms of burning mouth. Saliva possesses specific rheological properties as a result of its chemical, physical and biological characteristics - these properties being essential for maintaining balanced conditions within the oral cavity. Patients with burning mouth present evidence of changes in salivary composition and flow, as well as a probable alteration in the oral mucosal sensory perception related particularly to dry mouth and taste alterations. On the other hand, alterations in salivary composition appear to reflect on its viscosity and symptomatology of burning mouth. Saliva is a field open to much research related to burning mouth, and knowledge of its properties (e.g., viscosity) merits special attention in view of its apparent relationship to the symptoms of burning mouth. The present study describes our clinical experience with burning mouth, and discusses some of the aspects pointing to salivary alterations as one of the most important factors underlying stomatodynia.

[Burning mouth syndrome]

The burning mouth syndrome is a pathology characterized by burning oral mucoses. The etiological factors can be numerous. The Authors suggest a nosologic classification of this disease.