An updated review on pathophysiology and management of burning mouth syndrome with endocrinological, psychological and neuropathic perspectives

Comprehensive analysis of the oral microbiota and metabolome change in patients of burning mouth syndrome with psychiatric symptoms

Background

Burning mouth syndrome (BMS) is a chronic idiopathic facial pain with intraoral burning or dysesthesia. BMS patients regularly suffer from anxiety/depression, and the association of psychiatric symptoms with BMS has received considerable attention in recent years. The aims of this study were to investigate the potential interplay between psychiatric symptoms and BMS.

Methods

Using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC/MS) to evaluate the oral microbiota and saliva metabolism of 40 BMS patients [including 29 BMS patients with depression or anxiety symptoms (DBMS)] and 40 age matched healthy control (HC).

Results

The oral microbiota composition in BMS exhibited no significant differences from HC, although DBMS manifested decreased α-diversity relative to HC. Noteworthy was the discernible elevation in the abundance of proinflammatory microorganisms within the oral microbiome of individuals with DBMS. Parallel findings in LC/MS analyses revealed discernible disparities in metabolites between DBMS and HC groups. Principal differential metabolites were notably enriched in amino acid metabolism and lipid metabolism, exhibiting associations with infectious and immunological diseases. Furthermore, the integrated analysis underscores a definitive association between the oral microbiome and metabolism in DBMS.

Conclusions

This study suggests possible future modalities for better understanding the pathogenesis and personalized treatment plans of BMS.

The roles of 5-HT in orofacial pain

OBJECTIVES

Acute and chronic orofacial pain are very common and remain a vexing health problem that has a negative effect on the quality of life. Serotonin (5-HydroxyTryptamine, 5-HT) is a kind of monoamine neurotransmitter that is involved in many physiological and pathological processes. However, its role in orofacial pain remains inconclusive. Therefore, this review aims to summarize the recent advances in understanding the effect exerted by 5-HT on the modulation of orofacial pain.

SUBJECTS AND METHODS

An extensive search was conducted on PubMed and Web of Science for pertinent studies focusing on the effects of 5-HT on the modulation of orofacial pain.

RESULTS

In this review, we concisely review how 5-HT mediates orofacial pain, how 5-HT is regulated and how we can translate these findings into clinical applications for the prevention and/or treatment of orofacial pain.

CONCLUSIONS

5-HT plays a key role in the modulation of orofacial pain, implying that 5-HT modulators may serve as effective treatment for orofacial pain. However, further research on the precise mechanisms underlying the modulation of orofacial pain is still warranted.

White and Gray Matter Abnormality in Burning Mouth Syndrome Evaluated with Diffusion Tensor Imaging and Neurite Orientation Dispersion and Density Imaging

PURPOSE

Burning mouth syndrome (BMS) is defined by a burning sensation or pain in the tongue or other oral sites despite the presence of normal mucosa on inspection. Both psychiatric and neuroimaging investigations have examined BMS; however, there have been no analyses using the neurite orientation dispersion and density imaging (NODDI) model, which provides detailed information of intra- and extracellular microstructures. Therefore, we performed voxel-wise analyses using both NODDI and diffusion tensor imaging (DTI) models and compared the results to better comprehend the pathology of BMS.

METHODS

Fourteen patients with BMS and 11 age- and sex-matched healthy control subjects were prospectively scanned using a 3T-MRI machine using 2-shell diffusion imaging. Diffusion tensor metrics (fractional anisotropy [FA], mean diffusivity [MD], axial diffusivity [AD], and radial diffusivity [RD]) and neurite orientation and dispersion index metrics (intracellular volume fraction [ICVF], isotropic volume fraction [ISO], and orientation dispersion index [ODI]) were retrieved from diffusion MRI data. These data were analyzed using tract-based spatial statistics (TBSS) and gray matter-based spatial statistics (GBSS).

RESULTS

TBSS analysis showed that patients with BMS had significantly higher FA and ICVF and lower MD and RD than the healthy control subjects (family-wise error [FWE] corrected P < 0.05). Changes in ICVF, MD, and RD were observed in widespread white matter areas. Fairly small areas with different FA were included. GBSS analysis showed that patients with BMS had significantly higher ISO and lower MD and RD than the healthy control subjects (FWE-corrected P < 0.05), mainly limited to the amygdala.

CONCLUSION

The increased ICVF in the BMS group may represent myelination and/or astrocytic hypertrophy, and microstructural changes in the amygdala in GBSS analysis indicate the emotional-affective profile of BMS.

Clinical and epidemiological profile of burning mouth syndrome patients following the International Headache Society classification: a systematic review and meta-analysis

OBJECTIVE

This systematic review aimed to determine the clinical and epidemiologic profile of patients with burning mouth syndrome (BMS) following the current classification of the International Headache Society (IHS)-the International Classification of Headache Disorders (ICHD-3) and the International Classification of Orofacial Pain (ICOP).

STUDY DESIGN

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist and involved a comprehensive search on PubMed, Scopus, EMBASE, Web of Science, LILACS, and the gray literature.

RESULTS

Of the 4,252 studies identified, 41 were included. In general, there were no differences between the clinical and epidemiologic profiles of patients with BMS classified based on ICHD-3 or ICOP. Studies were pooled in meta-analyses and showed a significant prevalence of female patients between the sixth and seventh decade of life. The burning sensation and the tongue were the most prevalent descriptors and affected location. Significant associations were demonstrated between BMS and anxiety (P = .0006), depression (P = .004), and poor oral hygiene (P = .00001).

CONCLUSIONS

Under the existing contemporary classification systems, patients with BMS were found to be mostly females in the sixth and seventh decade of life with a burning sensation on the tongue. Experiencing depression and anxiety was a commonly existing comorbidity.

Age differences in pain sensitivity and effect of topical lidocaine on the tongue in healthy female subjects

PURPOSE

To assess the sensitivity and the effect of topical lidocaine on the tongue by quantitative sensory testing, comparing healthy middle-aged female subjects with healthy young female subjects.

METHODS

Sixteen healthy female subjects including eight in their fifties and eight in their twenties participated. They participated in two sessions at a 2-week interval in randomized order: lidocaine (experimental session) or placebo gel (placebo session) was applied on the tongue tip for 5min. The following parameters were taken on the tongue tip before and after application of the gel in each session: tactile detection threshold (TDT), filament-prick pain detection threshold (FPT), and numerical rating scale (NRS).

RESULTS

An increase of both TDT and FPT and a decrease of NRS were found after lidocaine application in both middle-aged and young female subjects. In the elder females, an increase of TDT, FPT, and NRS was also found after placebo gel application. However, the changes were not statistically significant, except for FPT in middle-aged subjects.

CONCLUSION

The reactions found after lidocaine application in middle-aged female subjects could be due to habituation as well as to the post-application effect of placebo gel. Placebo-induced changes appeared more pronounced in the elder females.

Case report: Neuropathic pain versus undesirable behavior in a Dachshund after hemilaminectomy surgery for an intervertebral disc extrusion

A 5.5 years-old male Dachshund was presented for evaluation because of undesirable behavior including barking, biting, sucking and licking the right-side flank, ventrally and slightly caudally to the level of the surgical incision 7 days after hemilaminectomy for a right-sided L1-2 intervertebral disc extrusion. The dog was being treated with oral gabapentin 10 mg/kg q8h. Repeat clinical examination on three occasions after post-operative discharge did not reveal any signs of hyperesthesia or neurological deficits and the behavior was not observed in the clinic during consultations. During a separate day of hospital admittance with the aim of evaluating for the presence or absence of the behavior, the dog also did not exhibit the behavior. Oral paracetamol 12 mg/kg q8h was added to medical treatment. When the dog was discharged and returned home, the behavior was immediately seen again. When the owners implemented verbal punishment, the behavior immediately ceased. The owner verbally corrected the dogs' behavior for two excitative days. Upon telephone consultation 3 days later, the owner reported that they only had observed three recurrences of the behavior that immediately ceased following verbal correction and did not recur thereafter. Oral analgesic medication was tapered and discontinued. No recurrence of the behavior was noticed during the next 2 months. The authors postulated the dog possibly expressed signs of neuropathic pain in the post-operative period, or that the behavior was of a "compulsive disorder-like" nature as it only occurred when the dog was at home and in the presence of the owner. The eventual outcome and result of verbal corrections implemented by the owner seem to support the latter. In conclusion, compulsive-like undesirable behavior should be considered a differential diagnosis in dogs in the post-operative period of procedures possibly associated with the development or expression of signs of neuropathic pain.

Case report: Remission of chronic low back pain and oral dysesthesia comorbid with attention deficit/hyperactivity disorder by treatment with atomoxetine and pramipexole

Introduction

Oral dysesthesia is a disease characterized by pain and/or abnormal sensations in the oral region, without any organic abnormality. Its symptoms include pain, and it is considered to be a disorder associated with idiopathic oral-facial pain. It is also known that idiopathic oral-facial pain tends to coexist with chronic musculoskeletal pain, including low back pain, even before its onset. Such coexisting idiopathic pain conditions are also called chronic overlapping pain conditions (COPCs). In general, COPCs are often refractory to treatment. Recently, it has been reported that attention deficit hyperactivity disorder (ADHD) is associated with many COPCs, such as pain in the facial and lower back regions and so on. However, there are no reports of (1) ADHD as a comorbidity with oral dysesthesia (OD) or (2) of the therapeutic effects of ADHD medications or dopamine agonists on low back pain and OD or an (3) evaluation of cerebral blood flow over time after treatment with these medications for OD and low back pain.

Case Presentation

In this study, we report the case of an 80-year-old man with OD and chronic low back pain that persisted for more than 25 years. His OD and chronic back pain were refractory to standard treatment, prevented him from continuing work, and tended to be exacerbated by conflicts in his relationship with his son. In recent years, ADHD has often been found to be comorbid with chronic pain, and ADHD medications have been reported to improve chronic pain as well. The patient was confirmed to have undiagnosed ADHD and was treated with the ADHD medication atomoxetine and dopamine agonist pramipexole, which dramatically improved his OD, chronic back pain, and cognitive function. Furthermore, along the course of treatment, there was improvement in cerebral blood flow in his prefrontal cortex, which was thought to reflect improved function in the region. Consequently, he was able to resume work and improve his family relationships.

Conclusion

Therefore, in the cases of ODs and COPCs, screening for ADHD and, if ADHD is diagnosed, ADHD medications or dopamine agonists may be considered.

Wearable and Invisible Sensor Design for Eye-Motion Monitoring Based on Ferrofluid and Electromagnetic Sensing Technologies

For many human body diseases, treatments in the early stages are more efficient and safer than those in the later stages; therefore, detecting the early symptoms of a disease is crucial. One of the most significant early indicators for diseases is bio-mechanical motion. This paper provides a unique way of monitoring bio-mechanical eye motion based on electromagnetic sensing technology and a ferro-magnetic material, ferrofluid. The proposed monitoring method has the advantages of being inexpensive, non-invasive, sensor-invisible and extremely effective. Most of the medical devices are cumbersome and bulky, which makes them hard to apply for daily monitoring. However, the proposed eye-motion monitoring method is designed based on ferrofluid eye make-up and invisible sensors embedded inside the frame of glasses such that the system is wearable for daily monitoring. In addition, it has no influence on the appearance of the patient, which is beneficial for the mental health of some patients who do not want to attract public attention during treatment. The sensor responses are modelled using finite element simulation models, and wearable sensor systems are created. The designed frame of the glasses is manufactured based on 3-D printing technology. Experiments are conducted to monitor eye bio-mechanical motions, such as the frequency of eye blinking. Both the quick blinking behaviour with an overall frequency of around 1.1 Hz and the slow blinking behaviour with an overall frequency of around 0.4 Hz can be observed through experimentation. Simulations and measurements results show that the proposed sensor design can be employed for bio-mechanical eye-motion monitoring. In addition, the proposed system has the advantages of invisible sensor set-up and will not affect the appearance of the patient, which is not only convenient for the daily life of the patient but also beneficial for mental health.

Physiology of the tongue with emphasis on taste transduction

The tongue is a complex multifunctional organ that interacts and senses both interoceptively and exteroceptively. Although it is easily visible to almost all of us, it is relatively understudied and what is in the literature is often contradictory or is not comprehensively reported. The tongue is both a motor and a sensory organ: motor in that it is required for speech and mastication, and sensory in that it receives information to be relayed to the central nervous system pertaining to the safety and quality of the contents of the oral cavity. Additionally, the tongue and its taste apparatus form part of an innate immune surveillance system. For example, loss or alteration in taste perception can be an early indication of infection as became evident during the present global SARS-CoV-2 pandemic. Here, we particularly emphasize the latest updates in the mechanisms of taste perception, taste bud formation and adult taste bud renewal, and the presence and effects of hormones on taste perception, review the understudied lingual immune system with specific reference to SARS-CoV-2, discuss nascent work on tongue microbiome, as well as address the effect of systemic disease on tongue structure and function, especially in relation to taste.

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.

Role of dairy proteins in the reduction of capsaicin-induced oral burning pain

Capsaicin-induced burning sensation in the oral mucosa can be relieved by skimmed and whole milk. The mechanism behind this effect, however, is unknown. This study aimed to asses the role of milk proteins in reducing capsaicin-induced oral burning sensation. 24 healthy participants were included in this single-blinded cross-over study consisting of four sessions. In each sessions, mucosal burning sensation was evoked by having the participants dip their tongues in a cup containing 0.1% capsaicin gel for a total of 8 min. The perceived levels of unpleasantness and burning intensity were scored on two different numerical rating scales. After capsaicin exposure, the participants rinsed their mouth for 10 s with a different solution in each session (3.5% casein, 3.5% whey, 3.5% lactose (non-protein control) and skimmed milk (active/positive control)). Mechanical (64, 128 and 256 mN pinprick) and thermal (5, 40, 45 and 50 ̊C) sensitivity of the tongue was measured using semi-quantative sensory testing at baseline, immediately after capsaicin exposure and when the scores for unpleasantness and burning intensity reached the minimum value of 0. Thermographic images of the tongue were taken at the same time-points. Overall, no statistically significant difference in unpleasantness and burning intensity was found between the four sessions (P ≥ 0.070). Explorative pair-wise comparisons, however, showed slight short-term reduction in unpleasantness and burning intensity when comparing the casein solution with the lactose solution (P ≤ 0.020). Scores for burning intensity and unpleasantness varied over time (P ≤ 0.001). Statistically significant changes in heat and mechanical sensitivity was observed between time-points (P < 0.001) but not sessions (P ≥ 0.410). An increased sensitivity towards heat and a decreased sensitivity towards mechanical stimuli was observed after capsaicin exposure compared with baseline (P < 0.001). Similarly, changes in thermographic temperature of the tongue was observed between time-points (P < 0.001), but not sessions (P ≥ 0.827). An increased maximum, minimum and average temperature of the tongue was observed immediately after capsaicin exposure compared with baseline (P < 0.001). In conclusion, short-term rinsing with room temperature milk proteins did not robustly alter capsaicin-induced oral burning sensation, unpleasantness, somatosensory changes or tongue temperature compared with control. Further studies exploring the effects of increased rinsing time and concentrations are needed in the future.

Diagnosis and treatment of intractable idiopathic orofacial pain with attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) has been reported to be associated with primary chronic pain syndromes, such as fibromyalgia, migraine, and chronic low back pain. Although idiopathic orofacial pain (IOP) is classified as burning mouth syndrome or persistent idiopathic facial or dentoalveolar pain and as a primary chronic pain, the association between IOP and ADHD has not been investigated. This retrospective cohort study investigated the severity of ADHD symptoms measured using the ADHD scale and the effects of treatment using ADHD drugs and the dopamine system stabilizer aripiprazole. The participants were 25 consecutive patients with refractory IOP referred to a psychiatrist and diagnosed with coexisting ADHD according to the Diagnostic and Statistical Manual of Mental Disorders-5. The ADHD scale scores were higher in patients with intractable IOP than those in the general population. Pharmacotherapy used in this study led to clinically significant improvements in pain, anxiety/depression, and pain catastrophizing. Intractable IOP and ADHD were shown to be associated. In the future, screening and pharmacotherapy for ADHD should be considered in the treatment of intractable IOP.

Burning Mouth Syndrome

Burning mouth syndrome (BMS) is a rare chronic neuropathic pain condition characterized by recurring burning pain or dysesthesia in the absence of any local or systemic causes of symptoms. The exact pathophysiology of BMS is unknown, but recent research suggests a medley of neuropathic, endocrinological, and psychosocial elements. This article presents a case history and reviews the epidemiology, diagnostic criteria, clinical features, diagnostic investigations, pathophysiology, and management of BMS.

Offset analgesia is increased intra-orally

BACKGROUND

Offset analgesia (OA) is commonly used to quantify endogenous pain inhibition. However, the potential role of afferent inputs and the subsequent peripheral factors from different body areas on the underlying mechanisms are still unclear.

OBJECTIVES

The aim of this cross-sectional study was to compare the magnitude of OA in four different body areas representing a) glabrous and non-glabrous skin, b) trigeminal and extra-trigeminal areas, and c) intra- and extra-oral tissue.

METHODS

OA was assessed at the oral mucosa of the lower lip, at the skin of the cheek, the forearm and the palm of the hand in 32 healthy and pain-free participants. OA testing included two trials: (1) a constant trial (30 seconds of constant heat stimulation at an individualized temperature of Pain₅₀ (pain intensity of 50 out of 100)), and (2) an offset trial (10 seconds of individualized Pain₅₀ , followed by 5 seconds at Pain₅₀ +1°C and 15 seconds at Pain₅₀ ). Participants continuously rated their pain during each trial with a computerized visual analog scale.

RESULTS

A significant OA response was recorded at the oral mucosa (p<0.001, d=1.24), the cheek (p<0.001, d=0.84) and the forearm (p<0.001, d=1.04), but not at the palm (p=0.19, d=0.24). Significant differences were shown for OA recorded at the cheek versus the mucosa (p=0.02), and between palm and mucosa (p=0.007), but not between the remaining areas (p>0.05).

CONCLUSION

This study suggests that intra-oral endogenous pain inhibition assessed with OA is enhanced and supports the role of peripheral mechanisms contributing to the OA response.

The use of self-report questionnaires in an analysis of the multidimensional aspects of pain and a correlation with the psychological profile and quality of life in patients with Burning Mouth Syndrome: a case control study

Background

The symptomatology in Burning Mouth Syndrome (BMS) is complex and it should be considered in accordance with a biopsychosocial model.

Objectives

To evaluate the multidimensional aspects of pain with a complete battery of tests and to analyse its relationship with potential predictors such as mood disorders, sleep and quality of life.

Methods

Forty patients with BMS versus an equal number of age and sex‐matched healthy controls were enrolled. The VAS, SF‐MPQ, BPI, PD‐Q, BDI‐II, STAI, PSQI, ESS, SF‐36 and OHIP‐14 were administered.

Results

The scores of the VAS, SF‐MPQ, BPI, PD‐Q, BDI‐II, STAI, PSQI, SF‐36 and OHIP‐14 were statistically significantly higher in the BMS patients than the controls (p < .001**). A strongly linear correlation between pain (VAS, SF‐MPQ, BPI and PD‐Q) and disease onset (STAI, BDI‐II, PSQI and sub‐items of SF‐36 and OHIP‐14) was found. In the multiple regression analysis, the contributions of the BDI‐II and OHIP‐14 were found to be statistically significant with the SF‐MPQ, PD‐Q and BPI in terms of severity and interference, while the contributions of the STAI and sleep were found to be statistically significant with the SF‐MPQ and BPI in terms of severity and interference, respectively.

Conclusions

Pain tests are differently correlated with mood and quality of life. Therefore, a complete analysis of the patient requires several tools to better understand the multidimensional aspects of pain in BMS.

Relationship between subjective taste sensations and taste strip test in patients with taste disorders with and without burning mouth syndrome

Background/purpose

Both subjective and objective evaluations are required to assess taste function. Evaluation of taste function has important clinical significances in patients with burning mouth syndrome (BMS) due to pain-taste interactions. The purpose of this study was to investigate the relationship between subjective and objective taste evaluations in patients with taste disorders based on the presence of BMS.

Materials and methods

Fifty–one patients with taste disturbances were included. The patients completed questionnaires on subjective taste sensations. The taste strip test was performed to examine objective taste function. The patients were divided into two groups: subjects with BMS (n = 24, 3 males and 21 females) and without BMS (n = 27, 8 males and 19 females).

Results

Significant differences were not observed in age, age distribution, and gender distribution between the groups. There were no significant differences in self-reported taste abilities based on the presence of BMS. However, the taste strip test showed higher correct answer rates for bitterness (P = 0.027) in the patients with BMS. In addition, a significant difference (P = 0.034) was observed in the distribution of objective types of taste disorders between the groups. A significant correlation between the subjective and objective evaluation results was observed only in patients with BMS.

Conclusion

In patients with taste disorders, patients with BMS had significant correlations between subjective and objective evaluations and different distributions in the types of taste disorders compared with those without BMS. The presence or absence of BMS should be evaluated in the diagnosis and management of taste disorders.

Efficacy of photobiomodulation in reducing pain and improving the quality of life in patients with idiopathic burning mouth syndrome. A systematic review and meta-analysis

Burning mouth syndrome is a chronic condition, which is characterised by a burning sensation or pain in the mucosa of the oral cavity. Treatment options include antidepressants, antipsychotics, anticonvulsants, analgesics, hormone replacement therapies and more recently photobiomodulation. This study aims to perform a systematic review with meta-analysis in order to determine the effect of photobiomodulation on pain relief and the oral health-related quality of life associated with this condition. A bibliographical search of the Pubmed, Embase, Web of Science and Scopus databases was conducted. Only randomised clinical trials were included. Pain and quality of life were calculated as mean difference and pooled at different treatment points (baseline = T0 and final time point = Tf) and laser modality. From a total of 103 records, 7 articles were retrieved for inclusion. PBM group had a greater decrease in pain than control group at Tf with a mean difference =  − 2.536 (IC 95% − 3.662 to − 1.410; I² = 85.33%, p < 0.001). An improvement in oral health-related quality of life was observed in both groups, although this was more significant in the photobiomodulation group mean difference =  − 5.148 (IC 95% − 8.576 to − 1.719; I² = 84.91%, p = 0.003). For the red laser, a greater improvement than infrared was observed, in pain, mean difference =  − 2.498 (IC 95% − 3.942 to − 1.053; I² = 79.93%, p < 0.001), and in quality of life, mean difference =  − 8.144 (IC 95% − 12.082 to − 4.206; I² = 64.22%, p = 0.027). Photobiomodulation, in particular, red laser protocols, resulted in improvement in pain and in quality of life of burning mouth syndrome patients.

A systematic review of treatment for patients with burning mouth syndrome

BACKGROUND

Burning mouth syndrome is a chronic idiopathic intractable intraoral dysaesthesia that remains a challenge to clinicians due to its poorly understood pathogenesis and inconsistent response to various treatments.

AIM

This review aimed to study the short- (≤3 months) and long-term (>3 months) effectiveness and sustainable benefit of different burning mouth syndrome treatment strategies and the associated side effects.

MATERIALS AND METHODS

Randomised controlled trials of burning mouth syndrome treatment compared with placebo or other interventions with a minimum follow up of 2 months were searched from the PubMed, Embase and Cochrane database (published to July 2020).

RESULTS

Twenty-two studies were selected based on the inclusion and exclusion criteria and analysed. Nine categories of burning mouth syndrome treatment were identified: Anticonvulsant and antidepressant agents, phytomedicine and alpha lipoic acid supplements, low-level laser therapy, saliva substitute, transcranial magnetic stimulation, and cognitive behaviour therapy. Cognitive behaviour therapy, topical capsaicin and clonazepam, and laser therapy demonstrated favourable outcome in both short- and long-term assessment. Phytomedicines reported a short-term benefit in pain score reduction. The pooled effect of alpha lipoic acid (ALA) pain score improvement was low, but its positive effects increased in long term assessment.

CONCLUSION

A more significant volume in terms of sample size, multi-centres, and multi-arm comparison of therapeutic agents with placebo and longitudinal follow-up studies is recommended to establish a standardised burning mouth syndrome treatment protocol. Further studies are required to assess the analgesic benefits of topical clonazepam and capsaicin, alternative medicines with neurodegenerative prevention capability and psychology support in treating burning mouth syndrome and reducing systemic adverse drug reactions.Registration International Prospective Register of Systematic Reviews (PROSPERO):Protocol ID - CRD42020160892.

Potential differences in somatosensory function during premenopause and early and late postmenopause in patients with burning mouth syndrome: An observational case-control study

Background/purpose

Burning mouth syndrome (BMS) is a chronic condition presenting as intraoral burning or dysesthesia, with a high preponderance in menopausal women. This study aimed to examine the association between somatosensory dysfunction and BMS in premenopausal, early postmenopausal, and late postmenopausal patients, using a standardized Quantitative Sensory Testing (QST) protocol, and to determine the predictive value of thermal or mechanical perception by QST for detecting BMS.

Materials and methods

An observational case–control study was performed with 36 female participants with BMS (12 premenopausal, 10 early postmenopausal, and 14 late postmenopausal) and 42 age- and sex-matched healthy volunteers (21 premenopausal, 10 early postmenopausal, and 11 late postmenopausal). Neurophysiological tests were used to evaluate somatosensory dysfunction at the tongue.

Results

Z-score in the late postmenopausal BMS group revealed a gain of function for the cold pain threshold and heat pain threshold (Z = 2.08 and 3.38, respectively). In the multiple regression analysis with the Visual Analog Scale as the dependent variable, the vibration detection threshold predicted the severity of burning mouth sensation in the premenopausal group.

Conclusion

Late postmenopausal patients with BMS showed an increased response of the tongue to noxious thermal stimuli. This supports the theory that changes in sex hormones may affect trigeminal somatosensory function, particularly during the late postmenopausal stage in patients with BMS.

Estrogen-dependent regulation of transient receptor potential vanilloid 1 (TRPV1) and P2X purinoceptor 3 (P2X3): Implication in burning mouth syndrome

Sex differences in the nervous system have gained recent academic interest. While the prominent differences are observed in mood and anxiety disorders, growing number of evidences also suggest sex difference in pain perception. This review focuses on estrogen as the key molecule underlying such difference, because estrogen plays many functions in the nervous system, including modulation of transient receptor potential vanilloid 1 (TRPV1) and P2X purinoceptor 3 (P2X3), two important nociceptive receptors. Estrogen was shown in various studies to up-regulate TRPV1 expression through two distinct pathways, resulting in pro-nociceptive effect. However, estrogen alleviated pain in other studies, by down-regulating nerve growth factor (NGF)-activated pathways and TRPV1. Estrogen may also attenuate nociception by inhibiting P2X3 receptors and ATP-signaling. Understanding the mechanism underlying the pro- and anti-nociceptive effect of estrogen might be crucial to understand pathophysiology of the burning mouth syndrome (BMS), a common chronic orofacial pain disorder in menopausal women. The involvement of TRPV1 is strongly suspected because of burning sensation. Reduced estrogen level of the BMS patient might have caused increased activity of P2X3 receptors. Interestingly, the increased expression of TRPV1 and P2X3 in oral mucosa of BMS patients was reported. The combinational impact of differential modulation of TRPV1/P2X3 during menopause might be an important contributing factor of etiology of BMS. Understanding the estrogen-dependent regulation of nociceptive receptors may provide a valuable insight toward the peripheral mechanism of sex-difference in pain perception.

[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.

Evaluation of serum neuron specific enolase levels among patients with primary and secondary burning mouth syndrome

INTRODUCTION

Burning mouth syndrome is a painful condition of the oral cavity with ambiguous pathogenesis and diagnosis. Neuron-specific enolase is increased in several conditions including peripheral neuropathy of diabetes, ophthalmopathies, spinal cord injuries and tumors. Evidence on association of burning mouth syndrome and neuron-specific enolase is limited.

AIM

This study aims to evaluate neuron-specific enolase levels in primary and secondary burning mouth syndrome patients and compare the levels of neuron-specific enolase with associated conditions in secondary burning mouth syndrome.

METHODS

One hundred and twenty-eight patients of more than 18 years of age with no gender predilection and having clinical symptoms of burning mouth syndrome and 135 healthy subjects were included. All the patients fulfilled Scala's criteria for the diagnosis of burning mouth syndrome, including "primary" (idiopathic) and "secondary" (resulting from identified precipitating factors) burning mouth syndrome patients. Blood samples were obtained from burning mouth syndrome patients. Serum neuron-specific enolase was evaluated using enzyme-linked immunosorbent assay. To compare means and standard deviations, among primary and secondary burning mouth syndrome, data was analysed with analysis of variance and multiple comparisons test.

RESULTS

The mean age of the study participants for burning mouth syndrome and healthy subjects was 53.30 and 51.6 years, respectively. Amongst the secondary burning mouth syndrome group, 32 (25%) of the patients had menopause, 15 (11.7%) had diabetes, eight (6.2%) of the patients had nutritional deficiency, seven (5.4%) had combined diabetes, menopause, and depression, six (4.6%) had combined diabetes and depression, four (3.1%) were diagnosed with Sjögren's syndrome. A minor percentage of 2.3% (three) had gastroesophageal reflux disease, while the remaining three (2.3%) patients in the secondary burning mouth syndrome group were on anti-depressants. There was a statistically significant increase in the levels of neuron-specific enolase in primary burning mouth syndrome as compared to the secondary burning mouth syndrome and healthy groups. Among the subgroups of secondary burning mouth syndrome, diabetic individuals showed a significant increase in neuron-specific enolase level when compared with other conditions in the secondary burning mouth syndrome patients.Discussion and conclusion: The raised serum neuron-specific enolase levels in patients suffering from primary burning mouth syndrome highlight a possible neuropathic mechanism. It was also increased in the sub-group of secondary burning mouth syndrome patients having diabetes. Although it cannot be ascertained whether the deranged values in the diabetic group were due to burning mouth syndrome or due to diabetes, the raised quantity of neuron-specific enolase in the primary burning mouth syndrome group is a reliable diagnostic indicator. Future studies on the assessment of neuron-specific enolase levels as a diagnostic tool for onset and management of primary and secondary burning mouth syndrome are recommended.

Psychophysical evaluation of somatosensory function in oro-facial pain: achievements and challenges

AIM

This critical review describes key methodological aspects for a successful oro-facial psychophysical evaluation of the somatosensory system and highlights the diagnostic value of somatosensory assessment and management perspectives based on somatosensory profiling.

METHODS

This topical review was based on a non-systematic search for studies about somatosensory evaluation in oro-facial pain in PubMed and Embase.

RESULTS

The recent progress regarding the psychophysical evaluation of somatosensory function was largely possible due to the development and application of valid, reliable and standardised psychophysical methods. Qualitative sensory testing may be useful as a screening tool to rule out relevant somatosensory abnormalities. Nevertheless, the patient should preferably be referred to a more comprehensive assessment with the quantitative sensory testing battery if confirmation of somatosensory abnormalities is necessary. Moreover, the identification of relevant somatosensory alterations in chronic pain disorders that do not fulfil the current criteria to be regarded as neuropathic has also increased the usefulness of somatosensory evaluation as a feasible method to better characterise the patients and perhaps elucidate some underpinnings of the so-called 'nociplastic' pain disorders. Finally, an additional benefit of oro-facial pain treatment based on somatosensory profiling still needs to be demonstrated and convincing evidence of somatosensory findings as predictors of treatment efficacy in chronic oro-facial pain awaits further studies.

CONCLUSION

Psychophysical evaluation of somatosensory function in oro-facial pain is still in its infancy but with a clear potential to continue to improve the assessment, diagnosis and management of oro-facial pain patients.

Evaluating the Suitability and Potential Efficiency of Cannabis sativa Oil for Patients with Primary Burning Mouth Syndrome: A Prospective, Open-Label, Single-Arm Pilot Study

OBJECTIVE

To evaluate the use of a Cannabis sativa oil in the management of patients diagnosed with primary burning mouth syndrome (BMS).

DESIGN

Prospective, open-label, single-arm pilot study.

SETTING

University hospital.

SUBJECTS

Seventeen patients with diagnosed BMS were included.

METHODS

Subjects were treated for 4 weeks with a full cannabis plant extract, which was prepared from standardized plant material (cannabis flos) in specialized pharmacies by means of Romano-Hazekamp extraction and was diluted in oil (1 g of cannabis in 10 g of olive oil). The primary outcome was the change in pain intensity (assessed by the visual analog scale, Present Pain Intensity scale, McGill Pain Questionnaire, and Oral Health Impact Profiles) at the end of the protocol and during the succeeding 24 weeks; the neuropathic pain was also investigated with a specific interview questionnaire (DN4-interview [Douleur Neuropathique en 4 Questions]). Levels of anxiety and depression were considered as secondary outcomes, together with reported adverse events due to the specified treatment.

RESULTS

Subjects showed a statistically significant improvement over time in terms of a clinical remission of the oral symptoms. Levels of anxiety and depression also changed statistically, displaying a favorable improvement. No serious reactions were detailed. None of the patients had to stop the treatment due to adverse events.

CONCLUSIONS

In this pilot evaluation, the C. sativa oil provided was effective and well tolerated in patients with primary BMS. Further bigger and properly defined randomized controlled trials, with different therapeutic approaches or placebo control, are needed, however.

Association Between Burning Mouth Syndrome and the Development of Depression, Anxiety, Dementia, and Parkinson Disease

Importance

Burning mouth syndrome is a chronic oral pain disorder that is characterized by a generalized or localized burning sensation without the presence of any specific mucosal lesions. It remains unclear, however, whether burning mouth syndrome is associated with the development of psychoneurological conditions among patients with the syndrome.

Objective

To evaluate the risk of developing psychoneurological conditions, including depression, anxiety, dementia, and Parkinson disease, in patients with burning mouth syndrome.

Design, Setting, and Participants

This retrospective population-based cohort study was conducted using a nationwide representative cohort sample from the Korean National Health Insurance Service-National Sample Cohort, which consists of data from approximately 1 million patients in South Korea. The study included 586 patients with burning mouth syndrome (patient group) and 1172 individuals without burning mouth syndrome (comparison group). The patient group included all patients who received inpatient and outpatient care for an initial diagnosis of burning mouth syndrome between January 1, 2002, and December 31, 2012. The comparison group was selected (2 individuals without burning mouth syndrome for each patient with burning mouth syndrome) using propensity score matching for sex, age, location of residence, household income level, and comorbidities. Data were collected and analyzed from January 1, 2002, to December 31, 2013.

Main Outcomes and Measures

Death and the incidence of psychopathological diseases. Affective disorder events that occurred among participants during the follow-up period were investigated using survival analysis, a log-rank test, and Cox proportional hazards regression models to estimate the incidence rates, survival rates, and hazard ratios, respectively, of participants who developed psychoneurological conditions.

Results

Of 1758 total participants, 1086 (61.8%) were female; 701 participants (39.9%) were younger than 45 years, 667 (37.9%) were aged 45 to 64 years, and 390 (22.2%) were older than 64 years. The overall incidence of depression and anxiety was higher in patients with burning mouth syndrome (n = 586; 30.8 incidents and 44.2 incidents per 1000 person-years, respectively) than in individuals without burning mouth syndrome (n = 1172; 11.7 incidents and 19.0 incidents per 1000 person-years, respectively). The results also indicated a similar incidence of dementia and Parkinson disease between the patient group (6.5 incidents and 2.5 incidents per 1000 person-years, respectively) and the comparison group (4.9 incidents and 1.7 incidents per 1000 person-years, respectively). After adjusting for sociodemographic factors (age, location of residence, household income level, and comorbidities), the adjusted hazard ratios for the development of depression and anxiety among patients with burning mouth syndrome were 2.77 (95% CI, 2.22-3.45) and 2.42 (95% CI, 2.02-2.90), respectively. However, no association was found between burning mouth syndrome and the risk of developing dementia and Parkinson disease.

Conclusions and Relevance

Results of this observational study suggest that burning mouth syndrome is associated with increases in the incidence of depression and anxiety but not in the incidence of dementia and Parkinson disease among patients with the syndrome. Clinicians should be aware of this association and be prepared to make referrals to appropriate mental health care professionals.

Catastrophising, pain self-efficacy and acceptance in patients with Burning Mouth Syndrome

BACKGROUND

Little is known about pain catastrophising, pain self-efficacy and chronic pain acceptance in burning mouth syndrome (BMS) and their effect on health-related quality of life (HRQoL) and symptoms of anxiety and depressive disorders.

OBJECTIVES

To describe pain catastrophising, pain self-efficacy and pain acceptance in BMS patients and explore associations with affective function and HRQoL.

METHODS

A cross-sectional study of 36 BMS patients (31 female) referred to an Orofacial Pain Clinic completed the Pain Catastrophizing Scale, the Pain Self-Efficacy Questionnaire and the Chronic Pain Acceptance Questionnaire-8 in addition to standardised self-reported questionnaires measuring mood and oral and generic HRQoL.

RESULTS

Pain catastrophising levels were markedly higher than (non-clinical) population norms, with 32.0% of patients reporting clinically relevant levels. Pain self-efficacy and chronic pain acceptance varied widely; 24.0% evidenced low confidence to cope with pain, and 53.8% reported low activity engagement and/or low pain willingness. Catastrophising showed moderate-to-strong associations with measures of anxiety (r = 0.63), depression (r = 0.80), and oral (r = 0.61) and generic HRQoL (rho=-0.84). Self-efficacy and acceptance were also closely related to levels of depression (r/rho=-0.83 to -0.73) and generic HRQoL (r/rho = 0.74 to 0.75). These associations were stronger than those between pain severity and affective function/HRQoL and persisted after controlling for pain severity.

CONCLUSIONS

A substantial proportion of BMS patients evidence maladaptive beliefs about personal effectiveness in managing pain, which is closely related to affective disorders and impaired HRQoL. As such, treatment approaches targeting catastrophising, pain self-efficacy and acceptance may prove beneficial in improving mood and quality of life in BMS patients.

Burning mouth syndrome: An update

Background:

Burning mouth syndrome (BMS) is a chronic and debilitating oral pain of the normal oral mucosa. It mainly affects women in their fifth to seventh decade. Its aetiopathogenesis remains unclear and is probably of multifactorial origin, with increasing evidence that BMS may be a neuropathic disorder. BMS is classified as an idiopathic (nociplastic) orofacial pain with or without somatosensory changes by International Classification of Orofacial Pain (ICOP 2020). The diagnosis of BMS, having excluded ‘oral burning mouth symptoms’, has evolved from basic intraoral exclusion screening to extensive clinical and laboratory investigations, which include the screening of comorbidities and other chronic pains and somatosensory testing. There is no standardised treatment in managing BMS, but a proposed combination of supportive and pharmacological treatment has been recommended.

Aim:

To review the current concepts of BMS definitions, classifications, aetiopathogenesis, diagnosis techniques, and evidence-based treatments in managing BMS patients.

Conclusion:

As BMS is a diagnosis by exclusion, thus a stratified approach is required for assessment of patients presenting BMS. A BMS diagnosis protocol is desired using a standardised screening to distinguish BMS from patient’s presenting with ‘oral burning symptoms’, and evaluation of comorbid chronic pain disorders or other medical comorbidities, which will include haematological, fungal, salivary flow, and qualitative sensory testing. Axis II and other additional quantitative sensory testing may further elucidate the causes of this condition. For future BMS prediction and prevention, will be based upon research on the relationship between other chronic pain disorders and familial history, environmental and genetic information.

Fight fire with fire: Neurobiology of capsaicin-induced analgesia for chronic pain

Capsaicin, the pungent ingredient in chili peppers, produces intense burning pain in humans. Capsaicin selectively activates the transient receptor potential vanilloid 1 (TRPV1), which is enriched in nociceptive primary afferents, and underpins the mechanism for capsaicin-induced burning pain. Paradoxically, capsaicin has long been used as an analgesic. The development of topical patches and injectable formulations containing capsaicin has led to application in clinical settings to treat chronic pain conditions, such as neuropathic pain and the potential to treat osteoarthritis. More detailed determination of the neurobiological mechanisms of capsaicin-induced analgesia should provide the logical rationale for capsaicin therapy and help to overcome the treatment's limitations, which include individual differences in treatment outcome and procedural discomfort. Low concentrations of capsaicin induce short-term defunctionalization of nociceptor terminals. This phenomenon is reversible within hours and, hence, likely does not account for the clinical benefit. By contrast, high concentrations of capsaicin lead to long-term defunctionalization mediated by the ablation of TRPV1-expressing afferent terminals, resulting in long-lasting analgesia persisting for several months. Recent studies have shown that capsaicin-induced Ca²⁺/calpain-mediated ablation of axonal terminals is necessary to produce long-lasting analgesia in a mouse model of neuropathic pain. In combination with calpain, axonal mitochondrial dysfunction and microtubule disorganization may also contribute to the longer-term effects of capsaicin. The analgesic effects subside over time in association with the regeneration of the ablated afferent terminals. Further determination of the neurobiological mechanisms of capsaicin-induced analgesia should lead to more efficacious non-opioidergic analgesic options with fewer adverse side effects.

Oral adverse effects: drug-induced tongue disorders

Objectives

Due to a worldwide increase in drug consumption, oral healthcare professionals are frequently confronted with patients using one or more drugs. A large number of drugs can be accompanied with adverse drug reactions in the orofacial region, amongst others of the tongue. This paper aims to give an overview of drugs that are known to be accompanied with tongue disorders.

Materials and methods

The national drug information database for Dutch pharmacists, composed of scientific drug information, guidelines and summaries of product characteristics, was analysed for drug‐induced tongue disorders. “MedDRA classification” and “Anatomical Therapeutic Chemical codes” were used to categorize the disorders.

Results

The database comprises of 1645 drugs of which 121 (7.4%) are documented to be accompanied with tongue disorders as an adverse effect. Drug‐induced tongue disorders are predominantly observed in the following drug categories: “nervous systems,” “anti‐infectives for systemic use” and “alimentary tract and metabolism”. The most common drug‐induced tongue disorders are glossitis, tongue oedema, tongue discoloration and burning tongue.

Conclusion

Healthcare professionals are frequently confronted with drugs that can cause tongue disorders. The overview of drugs reported in this article supports clinicians in their awareness, diagnosis and treatment of drug‐induced tongue disorders.

Vortioxetine versus other antidepressants in the treatment of burning mouth syndrome: An open-label randomized trial

OBJECTIVES

This randomized open-label trial compared the efficacy and tolerability of vortioxetine (15 mg/daily) with different antidepressants in the treatment of patients with burning mouth syndrome (BMS).

METHODS

One and hundred fifty BMS patients were randomized into five groups and treated with either vortioxetine, paroxetine (20 mg/daily), sertraline (50 mg/daily), escitalopram (10 mg/daily) or duloxetine (60 mg/daily). The Visual Analogue Scale (VAS), Total Pain Rating Index (T-PRI), Hamilton Rating Scales for Depression (HAM-D) and Anxiety (HAM-A), and Clinical Global Impression Improvement (CGI-I) and Efficacy scales (CGI-E) were performed at baseline and after 2, 4, 6, and 12 months of treatment. Any adverse events (AEs) were tabulated for each group. Descriptive statistics, including the Kruskal-Wallis non-parametric test and the Friedman non-parametric test for median comparisons between different times, were used.

RESULTS

All the antidepressants (AD) were associated with a significant decrease in the VAS, T-PRI, HAM-A, HAM-D, CGI-I, and CGI-E scores in the long-term (p < .001). However, the response rate of the vortioxetine group showed a significant reduction after six months. The medians, after 6 months, were as follows: VAS 0.0; T-PRI 2.0; HAM-A 7.0; HAM-D 7.0; CGI-I 1.0; and CGI-E 1.0 with a lower incidence of AEs (p < .019).

CONCLUSION

Vortioxetine was efficacious with a shorter latency of action and fewer AEs compared with other ADs.

Photobiomodulation Therapy in the Management of Burning Mouth Syndrome: Morphological Variations in the Capillary Bed

Burning mouth syndrome (BMS) is an idiopathic condition that manifests itself primarily with the onset of a burning sensation. The aim of this research was to perform photobiomodulation therapy (PBM) using a diode laser on the oral mucosa of BMS patients, followed by an objective evaluation of the morphological changes in the vascular bed underlying the mucosa using polarized light videocapillaroscopy. A group of 40 patients were included in the study. The patients were randomly divided into two groups (using simple randomization) as follows: 20 patients were assigned to the laser group and 20 patients were assigned to the placebo group. Each patient of the laser group received eight irradiations (with 4 Watt of power, wavelength 800 nm, energy 1200 Joules, irradiation time of 300 s, energy density 50 J/cm², 60 mW continuous wave laser, and irradiance 180 mW/cm²), twice a week, blinded to the type of irradiation administered, for four consecutive weeks. The patients in the placebo group underwent the same sessions as the other patients, the only difference was the non-emission of the laser. An initial check of the vascular bed was performed with a polarized light videocapillaroscope. This was followed by treatment with a therapeutic diode laser and a subsequent check with a videocapillaroscope. We observed that in the group of patients who underwent laser therapy, there was a lasting improvement in symptoms. The capillary oral bed of patients in the placebo group did not show any statistically significant difference (p > 0.05). In the laser group we observed the following: in the buccal mucosa the diameter of the capillary had a reduction of 3 μm; in the upper lip mucosa, there was a reduction of 3 μm; in the lower lip mucosa, there was a reduction of 3 μm; and in the dorsal lingual surface, there was a reduction of 2 μm. An increase in capillary length was also obtained in all irradiated regions in the laser group patients (p < 0.05). PBM induces microcirculatory changes that are still present over a long period of time, such as an improvement in the clinical picture. The improvement in the symptoms has been correlated to the reduction of the capillary diameter. The placebo effect only led to a temporary improvement in symptoms that were unrelated to changes in the microcirculatory pattern.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

This comprehensive review of the 2019 restorative dental literature is offered to inform busy dentists regarding remarkable publications and noteworthy progress made in the profession. Developed by the Scientific Investigation Committee of the American Academy of Restorative Dentistry, each author brings discipline-specific expertise to 1 of 8 sections of the report: (1) prosthodontics; (2) periodontics, alveolar bone, and peri-implant tissues; (3) implant dentistry; (4) dental materials and therapeutics; (5) occlusion and temporomandibular disorders; (6) sleep-related breathing disorders; (7) oral medicine and oral and maxillofacial surgery; and (8) dental caries and cariology. The report targets important information likely to influence day-to-day dental treatment decisions. Each review is not intended to stand alone but to update interested readers so that they may visit source material when greater detail is desired. As the profession moves toward evidence-based clinical decision-making, an incredible volume of potentially valuable dental literature continues to increase. It is the intention of this review and its authors to provide assistance in negotiating the extensive dental literature published in 2019. It is our hope that readers find this work useful in the clinical management of dental patients.

A perspective from experimental studies of burning mouth syndrome

Burning mouth syndrome (BMS) is one of the most frequently seen idiopathic pain conditions in a dental setting. Peri- and postmenopausal women are most frequently affected, and patients who experience BMS complain of persistent burning pain mainly at the tip and the bilateral border of the tongue. Recent studies have assessed whether BMS is a neuropathic pain condition, based on morphologic changes in biopsied tongue specimens, and whether there are abnormal pain responses in patients with this disease. Somatosensory studies have reported some abnormal findings in sensory and pain detection thresholds with inconsistency; however, the most distinct finding was exaggerated responses to painful stimuli. Imaging and electrophysiologic studies have suggested the possibility of dysregulation of the pain-modulating system in the central nervous system, which may explain the enhanced pain responses despite the lack of typical responses toward quantitative sensory tests. Basic studies have suggested the possible involvement of neuroprotective steroids, although the underlying mechanisms of this condition have not been elucidated. Experimental studies are looking for preferable supportive therapies for BMS patients despite the obscure pathogenesis.

Could methylene blue be used to manage burning mouth syndrome? A pilot case series

Objective: Burning mouth syndrome is a disabling condition of complex pathophysiology characterized by spontaneous pain felt in the oral mucosa in the absence of evident mucosal lesions which lacks efficient treatments to this day. The purpose of this study was to demonstrate the efficacy of methylene blue in the management of burning mouth syndrome. Methods: The study was conducted at the dental clinic of the Anta Diop University and Newtown dental clinic of Dakar, Senegal. A solution of methylene blue as a mouth-rinse (0.5%) was applied for 5 minutes in five patients satisfying the ICHD-3 diagnostic criteria for burning mouth syndrome. This procedure was repeated every 6 hours 3 times per 24h, during 7 days. Using numeric rating scale, pain severity was assessed as the mean pain felt during the last day of application. Results: After 7 days, the pain was significantly reduced by two-thirds and almost absent at 3 and 6 months follow-up. No secondary effects of the use of methylene blue were observed. Putative mechanisms of action and potential implications for treatment are discussed. Conclusion: Methylene blue is an old compound but a novel topical therapy that could prove beneficial in the management of burning mouth syndrome.