"Burning tongue" and "burning tip": the diagnostic challenge of the burning mouth syndrome

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.

Evaluation of peripheral nerve fibers and mast cells in burning mouth syndrome

Emerging evidence has revealed a cross-talk in the etiopathogenesis of burning mouth syndrome (BMS) related to peripheral nerve fibers (NF) and neuropeptides secreted by mast cells. Here, we investigated the S-100+ density and PGP 9.5+ integrity of peripheral NF and the tryptase+ mast cell density in the oral mucosa of BMS patients and healthy individuals. A total of 23 oral mucosa specimens (12 BMS and 11 controls) were evaluated. The clinical diagnosis of BMS was based on a careful examination, excluding other local and systemic causes. Samples were taken from an incisional biopsy of the tongue mucosa of individuals with symptomatic BMS, while the margins of the non-neoplastic tongue biopsy served as controls of healthy individuals. Immunohistochemistry was performed to determine the density/mm2 of S-100+, PGP 9.5+ peripheral NF, and tryptase+ mast cells. Similar densities of S-100+, PGP 9.5+ peripheral NF, and tryptase+ mast cells were found in cases of BMS, with a median value of 3.70, 0.70, and 29.24/mm2, respectively, and in the control group, with a median value of 2.60, 0.80, and 26.01/mm2, respectively (p > 0.05). Moreover, the relationship between S100+ and PGP 9.5+ peripheral NF was the same in both groups (p = 0.70). This study demonstrated that there were no alterations in the density and integrity of peripheral NF in the tongue of symptomatic BMS patients. However, the sensitization of peripheral NF in this disease may not depend on mast cell density.

The Utility of Capsicum annuum L. in Internal Medicine and In Dentistry: A Comprehensive Review

Capsaicin is a chili peppers extract, genus Capsicum, commonly used as a food spice. Since ancient times, Capsaicin has been used as a "homeopathic remedy" for treating a wild range of pathological conditions but without any scientific knowledge about its action. Several studies have demonstrated its potentiality in cardiovascular, nephrological, nutritional, and other medical fields. Capsaicin exerts its actions thanks to the bond with transient receptor potential vanilloid subtype 1 (TRPV1). TRPV1 is a nociceptive receptor, and its activation starts with a neurosensitive impulse, responsible for a burning pain sensation. However, constant local application of Capsaicin desensitized neuronal cells and leads to relief from neuropathic pain. In this review, we analyze the potential adjuvant role of Capsaicin in the treatment of different pathological conditions either in internal medicine or dentistry. Moreover, we present our experience in five patients affected by oro-facial pain consequent to post-traumatic trigeminal neuropathy, not responsive to any remedy, and successfully treated with topical application of Capsaicin. The topical application of Capsaicin is safe, effective, and quite tolerated by patients. For these reasons, in addition to the already-proven beneficial actions in the internal field, it represents a promising method for the treatment of neuropathic oral diseases.

Meine Zunge brennt! – Glossodynie/orofaziales Schmerzsyndrom

Die Glossodynie, die besser als orofaziales Schmerzsyndrom oder Burning-Mouth-Syndrom bezeichnet wird, stellt eine therapeutische Crux dar, da eine eindeutige Ätiopathogenese bisher nicht bekannt ist. Neuere Studien weisen auf einen Zusammenhang mit neuropathischen Veränderungen hin, außerdem sind Hinweise auf Komorbiditäten mit Depression, Angst und Karzinophobie evident. Diese sind zum Teil auch Folge der Erkrankung und nicht unbedingt als ursächlich anzusehen. Da eine vielfältige Differenzialdiagnostik durch klinische Untersuchungen ausgeschlossen werden sollte, ist die Glossodynie eine diagnostische Herausforderung. In Betracht kommen neben Lichen planus, Leukoplakien, Pemphigus vulgaris und Aphthen auch internistische Erkrankungen wie Diabetes oder Anämien oder Vitaminmangel und hormonelle Einflüsse bei den überwiegend älteren und überwiegend weiblichen Patienten. Metaanalysen über durchgeführte Therapiestudien zeigen einen niedrigen Evidenzgrad der vorhandenen randomisierten kontrollierten Studien (RCTs). Nach der Literatur werden v. a. Psychotherapie und Antidepressiva zur Behandlung vorgeschlagen. Alpha-Liponsäure als Nahrungsergänzung zeigt eine kurzfristige Besserung, und auch Low-Level-Lasertherapie scheint gewisse Effekte hervorzubringen.

Role of Photobiomodulation Therapy in Neurological Primary Burning Mouth Syndrome. A Systematic Review and Meta-Analysis of Human Randomised Controlled Clinical Trials

Mitochondrial homeostasis is crucial for energy production and neuronal survival in neurological primary burning mouth syndrome (npBMS). Photobiomodulation therapy (PBMT) has been utilised in npBMS management, however, its role of intervention remains controversial. The aim of this systematic review and meta-analysis of CRD 42020198921 PROSPERO registration reference was to oversee and determine the efficacy of PBMT in patients with npBMS, identifying the gaps and bridge them by proposing recommendations for future studies purposes. PRISMA guidelines and Cochrane Collaboration recommendations followed. Various search engines employed to analyse a total of 351 studies of which 12 were included. A wide range of utilised PBM wavelengths was between 635-980 nm and the power output ranged between 30 mW and 4000 mW. A high risk of bias (RoB) was noted in 7 out of 12 included studies (58.3%), as results of qualitative analysis. Meta-analysis findings of 4 out of 12 studies showed statistically significant intergroup differences (SSID) for visual analogue scale (VAS) values (MD = -1.47; 95% CI = -2.40 to -0.53; Z = 3.07 (p = 0.002) whereas meta-analysis on 5 out of 12 studies revealed SSID for anxiety/depression and quality of life (MD = -1.47; 95% CI = -2.40 to -0.53; Z = 3.07 (p = 0.002), favouring PBMT group to the control treatment strategies. Despite the inconsistency and diversity in PBM parameters (wavelength, power, light source, spot size, emission mode, energy per point, total energy) and treatment protocols (exposure time, number of sessions, time interval between sessions, treatment duration)-majority of the included studies showed positive PBM results. The high RoB and meta-analytical heterogeneity in the eligible studies warrant the necessity to perform well-designed and robust RCTs after acknowledging the drawbacks of the available scientific literature and addressing our suggested recommendations highlighted in our review.

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.

Neuropathic and Psychogenic Components of Burning Mouth Syndrome: A Systematic Review

The pathophysiology of primary burning mouth syndrome (BMS) has been extensively debated but is poorly understood despite a large number of hypotheses attempting to explain its etiopathogenic mechanisms. The aim of the present work was to systematically review papers that could provide arguments in favour of the neuropathic and psychogenic components of primary BMS for a better understanding of the disease. This systematic review (SR) was registered in PROSPERO (CRD42021224160). The search was limited to articles in English or French from 1990 to 01 December 2020. A total of 113 articles were considered for data extraction. We divided them into four subgroups: pharmacological and nonpharmacological management studies (n = 23); neurophysiological studies (n = 35); biohistopathological studies (n = 25); and questionnaire-based studies (n = 30). Several of these studies have shown neuropathic involvement at various levels of the neuraxis in BMS with the contribution of quantitative sensory testing (QST), functional brain imaging, and biohistopathological or pharmacologic studies. On the other hand, the role of psychological factors in BMS has also been the focus of several studies and has shown a link with psychiatric disorders such as anxiety and/or depression symptoms. Depending on the patient, the neuropathic and psychogenic components may exist simultaneously, with a preponderance of one or the other, or exist individually. These two components cannot be dissociated to define BMS. Consequently, BMS may be considered nociplastic pain.

Non-length-dependent small fiber neuropathy: Not a matter of stockings and gloves

The clinical spectrum of small fiber neuropathy (SFN) encompasses manifestations related to the involvement of thinly myelinated A-delta and unmyelinated C fibers, including not only the classical distal phenotype, but also a non-length-dependent (NLD) presentation that can be patchy, asymmetrical, upper limb-predominant, or diffuse. This narrative review is focused on NLD-SFN. The diagnosis of NLD-SFN can be problematic, due to its varied and often atypical presentation, and diagnostic criteria developed for distal SFN are not suitable for NLD-SFN. The topographic pattern of NLD-SFN is likely related to ganglionopathy restricted to the small neurons of dorsal root ganglia. It is often associated with systemic diseases, but about half the time is idiopathic. In comparison with distal SFN, immune-mediated diseases are more common than dysmetabolic conditions. Treatment is usually based on the management of neuropathic pain. Disease-modifying therapy, including immunotherapy, may be effective in patients with identified causes. Future research on NLD-SFN is expected to further clarify the interconnected aspects of phenotypic characterization, diagnostic criteria, and pathophysiology.

Acute and Chronic Pain from Facial Skin and Oral Mucosa: Unique Neurobiology and Challenging Treatment

The oral cavity is a portal into the digestive system, which exhibits unique sensory properties. Like facial skin, the oral mucosa needs to be exquisitely sensitive and selective, in order to detect harmful toxins versus edible food. Chemosensation and somatosensation by multiple receptors, including transient receptor potential channels, are well-developed to meet these needs. In contrast to facial skin, however, the oral mucosa rarely exhibits itch responses. Like the gut, the oral cavity performs mechanical and chemical digestion. Therefore, the oral mucosa needs to be insensitive, to some degree, in order to endure noxious irritation. Persistent pain from the oral mucosa is often due to ulcers, involving both tissue injury and infection. Trigeminal nerve injury and trigeminal neuralgia produce intractable pain in the orofacial skin and the oral mucosa, through mechanisms distinct from those seen in the spinal area, which is particularly difficult to predict or treat. The diagnosis and treatment of idiopathic chronic pain, such as atypical odontalgia (idiopathic painful trigeminal neuropathy or post-traumatic trigeminal neuropathy) and burning mouth syndrome, remain especially challenging. The central integration of gustatory inputs might modulate chronic oral and facial pain. A lack of pain in chronic inflammation inside the oral cavity, such as chronic periodontitis, involves the specialized functioning of oral bacteria. A more detailed understanding of the unique neurobiology of pain from the orofacial skin and the oral mucosa should help us develop novel methods for better treating persistent orofacial pain.

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.

Psycho-stomatodynia

Introduction:Burning mouth syndrome is an enigmatic condition whose etiopathogenic origin remains largely unknown and whose treatment remains unsatisfactory. It is often considered to be of “psychosomatic” origin, and this etiology is frequently reported in the French medical literature.Corpus:This narrative review examines the arguments supporting this point of view, in its historical, clinical, and therapeutic aspects, in order to shed light on the patientʼs point of view.Conclusion:The etiopathogenic uncertainty does not let us give the patient an erroneous conception of the affliction.

Is it Sjögren's syndrome or burning mouth syndrome? Distinct pathoses with similar oral symptoms

Sjögren's syndrome (SS) and burning mouth syndrome (BMS) typically occur in postmenopausal women. Although these conditions have significantly different etiopathogeneses, patients with SS or BMS often present with analogous oral complaints. The similarities between the two conditions have led to considerable confusion on the part of medical and dental practitioners, and those with BMS or SS often wait years to receive a diagnosis. Therefore, it is imperative for clinicians to understand the characteristic subjective and objective features of each disease and how these can be used to distinguish them. This review will discuss the proposed etiology, clinical manifestations, histopathology, diagnostic criteria, and patient management of SS and BMS. We also identify key differences between the two pathoses that aid in establishing the correct diagnosis. Recognition of the defining features of each condition will lead to reduced time to diagnosis and improved patient management for these poorly understood conditions.

Interventions for treating burning mouth syndrome

BACKGROUND

Burning mouth syndrome (BMS) is a term used for oral mucosal pain (burning pain or discomfort in the tongue, lips or entire oral cavity) without identifiable cause. General population prevalence varies from 0.1% to 3.9%. Many BMS patients indicate anxiety, depression, personality disorders and impaired quality of life (QoL). This review updates the previous versions published in 2000 and 2005.

OBJECTIVES

To determine the effectiveness and safety of any intervention versus placebo for symptom relief and changes in QoL, taste, and feeling of dryness in people with BMS.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 31 December 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 11) in the Cochrane Library (searched 31 December 2015), MEDLINE Ovid (1946 to 31 December 2015), and Embase Ovid (1980 to 31 December 2015). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. We placed no restrictions on the language or date of publication when searching the electronic databases SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing any treatment against placebo in people with BMS. The primary outcomes were symptom relief (pain/burning) and change in QoL. Secondary outcomes included change in taste, feeling of dryness, and adverse effects.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Outcome data were analysed as short-term (up to three months) or long-term (three to six months).

MAIN RESULTS

We included 23 RCTs (1121 analysed participants; 83% female). Interventions were categorised as: antidepressants and antipsychotics, anticonvulsants, benzodiazepines, cholinergics, dietary supplements, electromagnetic radiation, physical barriers, psychological therapies, and topical treatments.Only one RCT was assessed at low risk of bias overall, four RCTs' risk of bias was unclear, and 18 studies were at high risk of bias. Overall quality of the evidence for effectiveness was very low for all interventions and all outcomes.Twenty-one RCTs assessed short-term symptom relief. There is very low-quality evidence of benefit from electromagnetic radiation (one RCT, 58 participants), topical benzodiazepines (two RCTs, 111 participants), physical barriers (one RCT, 50 participants), and anticonvulsants (one RCT, 100 participants). We found insufficient/contradictory evidence regarding the effectiveness of antidepressants, cholinergics, systemic benzodiazepines, dietary supplements or topical treatments. No RCT assessing psychological therapies evaluated short-term symptom relief.Four studies assessed long-term symptom relief. There is very low-quality evidence of a benefit from psychological therapies (one RCT, 30 participants), capsaicin oral rinse (topical treatment) (one RCT, 18 participants), and topical benzodiazepines (one RCT, 66 participants). We found no evidence of a difference for dietary supplements or lactoperoxidase oral rinse. No studies assessing antidepressants, anticonvulsants, cholinergics, electromagnetic radiation or physical barriers evaluated long-term symptom relief.Short-term change in QoL was assessed by seven studies (none long-term).The quality of evidence was very low. A benefit was found for electromagnetic radiation (one RCT, 58 participants), however findings were inconclusive for antidepressants, benzodiazepines, dietary supplements and physical barriers.Secondary outcomes (change in taste and feeling of dryness) were only assessed short-term, and the findings for both were also inconclusive.With regard to adverse effects, there is very low-quality evidence that antidepressants increase dizziness and drowsiness (one RCT, 37 participants), and that alpha lipoic acid increased headache (two RCTs, 118 participants) and gastrointestinal complaints (3 RCTs, 138 participants). We found insufficient/contradictory evidence regarding adverse events for anticonvulsants or benzodiazepines. Adverse events were poorly reported or unreported for cholinergics, electromagnetic radiation, and psychological therapies. No adverse events occurred from physical barriers or topical therapy use.

AUTHORS' CONCLUSIONS

Given BMS' potentially disabling nature, the need to identify effective modes of treatment for sufferers is vital. Due to the limited number of clinical trials at low risk of bias, there is insufficient evidence to support or refute the use of any interventions in managing BMS. Further clinical trials, with improved methodology and standardised outcome sets are required in order to establish which treatments are effective. Future studies are encouraged to assess the role of treatments used in other neuropathic pain conditions and psychological therapies in the treatment of BMS.

Peripheral nervous system involvement in primary burning mouth syndrome--results of a pilot study

OBJECTIVE

The pathophysiology of primary burning mouth syndrome (BMS) has remained enigmatic, but recent studies suggest pathology within the nervous system at multiple levels. This study aimed to investigate in detail the contribution of either focal or generalized alterations within the peripheral nervous system (PNS) in the etiopathogenesis of BMS.

SUBJECTS AND METHODS

Intraepithelial nerve fiber density (IENFD) of tongue mucosa was assessed in 10 carefully characterized BMS, and the results were compared to 19 age- and gender-matched cadaver controls, 6 with lifetime diabetes. Extensive neurophysiologic and psychophysical examinations of the trigeminal system and distal extremities were performed to profile PNS function in BMS.

RESULTS

Patients with BMS had significantly fewer intraepithelial nerve fibers (0,27, s.e. 0,18 mm(-1); P = 0.0253) than non-diabetic controls (0,92, s.e. 0,15 mm(-1)). In the subepithelial space, the amount of nerve fibers did not differ between the groups. The majority (9/10) of patients with BMS showed neurophysiologic or psychophysical signs of a more generalized PNS dysfunction.

CONCLUSIONS

Our results in neurophysiologically optimally characterized BMS patients confirm that pure focal small fiber neuropathy of the oral mucosa has a role in the pathophysiology of primary BMS. Furthermore, BMS may be related to a more generalized, yet subclinical peripheral neuropathy.

Managing a patient with burning mouth syndrome

A 64-year-old woman presented with an increasing frequency of symptoms of heartburn and retrosternal pain over the last few months, and a constant and intense burning pain affecting her tongue tip, mouth and lips for the past 5 years. She found consuming hot drinks exacerbated the burning oral pain and chewing gum seemed to alleviate some of her symptoms. She thought these oral sensations were caused by frequently licking her finger tips to separate prints in her work in publishing. She had been previously diagnosed with gastro-oesophageal reflux disease (GORD), and her heartburn symptoms had been controlled until recently with lansoprazole 15 mg daily. Her past medical history included irritable bowel syndrome and depression, for which she had been treated with mebeverine and paroxetine for a number of years. She was a non-smoker and did not consume alcohol. Clinical examination was unremarkable with no oral lesions on examination. Her routine laboratory tests, including autoimmune serology, haematinics and thyroid function tests were all within normal limits. She underwent a gastroscopy, which revealed moderate reflux oesophagitis, and following commencing omeprazole 20 mg twice daily, her heartburn resolved. However, her oral burning symptoms were not affected and a diagnosis of burning mouth syndrome (BMS) was made. Following explanation and reassurance concerning the cause of her BMS symptoms, she chose not to receive treatment for this but to access cognitive behavioural therapy in the future if her symptoms worsened.

Morphological evaluation of tongue mucosa in burning mouth syndrome

OBJECTIVE

The aim of the present study was to perform a morphological evaluation by immunofluorescence of biomarkers of keratinocyte intercellular adhesion, and of differentiation in the tongue mucosa of burning mouth syndrome patients (BMS), compared with a control group.

DESIGN

A prospective blinded evaluation of tongue mucosal specimens processed for light microscopy was performed. Intercellular adhesion was evaluated by investigating the expression of desmoglein 1, desmoglein 3, and of occludin. Keratin 10 and keratin 14 (markers of epithelial differentiation) were also evaluated, as keratin 16 (marker for activated keratinocytes after epithelial injury). Apoptotic cascade was investigated by p53 and activated caspase-3 expression. The basal membrane integrity was analysed through laminin immunoreactivity.

RESULTS

In both groups, a preserved three-dimensional architecture of the tongue was observed. Desmoglein 1 and desmoglein 3 epithelial distributions were similar in the desmosomes of patients and control subjects. Again, keratin 10 immunoreactivity and distribution pattern of keratin 14 in the epithelial compartment was similar in both groups. In control samples, keratin 16 immunoreactivity was scant throughout the epithelium with a punctuate and scattered cytoplasmic labelling. In contrast, in all BMS patients keratinocyte cytoplasm was homogeneously labelled for keratin 16, with a more intense staining than controls. Furthermore, keratin 16 staining progressively decreased proceeding towards the most superficial epithelial layers.

CONCLUSIONS

The results of this study are consistent with and support the clinically normal features of oral mucosa in BMS, and suggest that keratin 16 may be involved in the cell mechanisms underlying the syndrome occurrence.