Oral Mucosa Research Articles

Permanent intramural stenting with polyethylene catheter to resolve parotid salivary duct stenosis secondary to sialolithiasis

SummarySialolithiasis is an uncommon condition of the salivary gland in the horse, primarily affecting the parotid salivary duct. Clinical signs may include salivary stasis within the gland and potential progression to sialadenitis, facial draining tract or a permanent fistula. A 19‐year‐old Warmblood gelding was referred with septic sialadenitis of the right parotid gland. A 4 cm sialolith was detected radiographically and removed surgically. Although surgery was uneventful and patency of the salivary duct was assessed intraoperatively, mild accumulation of saliva within the gland was noted 1 day later. A stenosis caudal to where the sialolith was lodged was diagnosed through contrast radiography. Balloon dilatation of the stenosis was attempted unsatisfactorily, and a polyethylene catheter was placed and sutured to the oral mucosa to maintain the parotid emptying. A week later, the oral portion of the catheter was chewed by the horse, preventing catheter removal without surgery. Subsequently, ultrasonographic and radiographic re‐evaluations were performed routinely to assess the patency of the catheter or complications associated with long‐term placement. After 1 year, no salivary stasis in the gland or complications were observed. This is the first description of successful long‐term indwelling catheter placement to resolve stenosis of the salivary duct. This procedure may offer a simple, economical and safe option compared to more complicated or invasive techniques previously described in horses, with excellent functional and cosmetic results.

Capecitabine-induced Hand-foot Syndrome with Hyperpigmentation on Oral Mucosa and Nails: A Rare Entity

Capecitabine-induced Hand-foot Syndrome with Hyperpigmentation on Oral Mucosa and Nails: A Rare Entity

Optimization of Mucoadhesive Oral Films Containing Olive Leaf Extract and Microencapsulated Thyme Essential Oil With Potential Antimicrobial Activity.

In this study, developing mucoadhesive oral films with optimized olive leaf extract (OLE) and microencapsulated thyme essential oil (TEO) contents was aimed to create a novel oral delivery system with desirable film properties as well as enhanced bioactivities. For this, TEO-containing sodium alginate/okra gum microcapsules were first fabricated at optimized electrospray conditions, where optimization was performed for three parameters, which are the flow rate of the emulsion solution, the potential difference, and the distance between the nozzle of the sample container and the collector plate, through three-level centered Box-Behnken design. Prior to the inclusion of the OLE in custom-designed mucoadhesive films, polymeric components of the films were also optimized through a separate multi-variable, three-level Box-Behnken experimental design by which the effect of mixing ratios of Carbopol 934, hydroxypropyl methylcellulose and polyethylene glycol on viscosity, solution pH, film pH, disintegration time, thickness, and weight were elaboratively investigated. The resulting films, containing OLE and microencapsulated TEO, obtained through solvent casting were characterized for pH, viscosity, mass uniformity and thickness, dispersion, tensile strength, folding endurance, contact angle, invitro mucoadhesion time, and exvivo mucoadhesion force. Results showed that the film had good tensile strength, swelling capacity, compatibility with oral mucosa, and flexibility. It also demonstrated desirable stability and adhesion ability. Regarding bioactivity, the film was found to have desirable antioxidant capacity and it was non-toxic to fibroblast cells when diluted to certain concentration. Moreover, antiviral studies indicated reductions of 32.39% and 54.29% against Poliovirus Type 1 and Murine Norovirus, respectively, while preliminary antibacterial tests showed no significant reduction in certain bacteria within 1 min, but a logarithmic reduction in Staphylococcus aureus was observed. Despite favorable mucoadhesion properties and physical attributes, further investigation is needed to enhance the antimicrobial effectiveness of the films for their potential utilization in drug delivery systems.

Evaluation of gum odina/carbopol composite mucoadhesive hydrogel on pharmaceutical performance: Focusing on potential periodontal treatment.

Antimicrobial buccal hydrogel made of polymers have gained tremendous utilisation in biomedical field. Dual drug loaded, porous materials are important areas of research for medical and pharmaceutical industries. In this regard, a series of hydrogels (F1, F2, F3) were prepared with gum odina and carbopol 940 in aqueous solution with calcium chloride as the cross linker and glycerol as plasticizer by ionotropic gelation method. The buccal hydrogel was evaluated for thermal stability (TGA/DSC) revealing them to be thermally stable. The SEM and AFM studies of the optimized formulation (F2) exhibits cracks and porous structure. It also depicted good injectability and self-healing. The XRD result displayed amorphous nature of the formulation (F2) making them soluble in buccal fluids. The chemical nature and interactions were analysed by FTIR study. The release profile portrayed controlled release patterns for amoxicillin trihydrate and fluconazole. Appreciable mucoadhesion time (6±0.7h) and strength (12.03±0.45g) was observed in case of F2. The optimized formulation F2 displayed good antifungal and antibacterial properties. Thus, it is concluded that the hydrogel formed were mucoadhesive and highly potent to carry drug molecules for controlled release in the buccal mucosa to treat several periodontal infections.

Improved Efficacy of a Predictive Model for Swallowing-Induced Breakthrough Pain Based on a Redefined Delineation Method in Locally Advanced Nasopharyngeal Carcinoma.

The objective of this study was to explore the performance of a predictive model for swallowing-induced breakthrough pain established using a redefined delineation method based on the common occurrence sites of radiation-induced oral mucositis (RIOM) in locally advanced nasopharyngeal carcinoma (NPC). A total of 208 patients with locally advanced NPC were included in the study cohort, and the test cohort consisted of 88 patients. The oral mucosa structure was contoured using oral cavity contour (OCC), mucosal surface contour (MSC), and oral-pharyngeal mucosa (OPM) methods, and relevant dosimetric parameters were collected. Assessment of the severity of RIOM was made with the National Cancer Institute's Common Terminology Criteria for Adverse Events, version 4.0. The random forest classification method was chosen to establish and validate the predictive models based on 3 contouring methods. The area under the curve of the OPM-based model was higher than that of the OCC- and MSC-based models in both the validation cohort and the test cohort (0.800, 0.739, and 0.750; 0.670, 0.605, and 0.609, respectively). Better predictive performance could also be observed under the OPM method than the OCC and MSC methods in terms of accuracy. The OPM-based model showed high specificity (greater than 90%) in both the validation cohort and the test cohort. According to the mean decrease in the Gini index, the maximum dose was the most important predictor of severe oral mucositis in the OPM-based model. We redefined a delineation method for oral mucosa structure based on the common occurrence sites of RIOM in locally advanced NPC. The model for swallowing-induced breakthrough pain constructed based on this method demonstrated good predictive performance. New parameters were found as predictors of severe swallowing-induced breakthrough pain in locally advanced NPC.

Evaluation of Preclinical Efficacy of Curcumin-Loaded Bicosome Systems in Amelioration of Oral Mucositis

Background/Objectives: Oral mucositis (OM) is a common and debilitating side effect of cancer therapy, characterized by ulceration or inflammation of the oral mucosa. This study evaluates the preclinical efficacy of curcumin-loaded bicosome systems (cur-BS) in mitigating chemotherapy-induced OM in mice. Methods: BS were prepared using a combination of 1,2-di-palmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC), α-tocopherol, and curcumin, encapsulated within liposomal vesicles. Three formulations with different curcumin concentrations (180, 540, and 900 μM) were characterized by particle size, polydispersity index (PDI), encapsulation efficiency (EE), appearance, and morphology. The formulation with the highest concentration (cur-BS 5×) was selected for ex vivo permeability studies, release profile analysis, and in vitro anti-inflammatory efficacy. OM was induced in mice using 5-fluorouracil (5-FU) and acetic acid. Cur-BS 5× was compared to the commercial product Dentoxol®. Results: The results showed that cur-BS 5× provided sustained release through a mechanism involving both diffusion and matrix relaxation, enhancing curcumin retention in deeper skin layers. Treatment with cur-BS 5× downregulated the expression of inflammatory markers (IL-1β and TNF-α). Macroscopic assessments demonstrated that both cur-BS 5× and Dentoxol® reduced OM severity, with the greatest improvement observed between days 6 and 9. By day 24, OM scores were 1.25 ± 0.5 for cur-BS 5× and 1.0 ± 0.0 for Dentoxol®, indicating effectiveness in both treatments. However, histological analysis revealed superior tissue recovery with cur-BS 5×, showing better epithelial structure and reduced inflammation. Cur-BS 5×-treated mice also exhibited greater weight recovery and higher survival rates compared to the Dentoxol® group. Conclusions: These findings suggest that cur-BS 5× may enhance OM treatment, offering outcomes comparable to or better than those of Dentoxol®.

Localization of Lesions in Autoimmune Blistering Diseases Is Independent of Site-Specific Target Antigen Expression

Autoimmune blistering diseases (AIBDs) involve autoantibodies targeting proteins in the epidermal/epithelial desmosome (pemphigus) or basement membrane zone (pemphigoid). Despite widespread antigen distribution, lesions exhibit a scattered involvement pattern. This study maps the frequency/severity of AIBD lesions on various body parts and investigates whether differential antigen expression contributes to specific predilection sites. We analyzed affected sites presenting blisters/erosions, erythematous/urticarial lesions, and mucosal lesions in bullous pemphigoid (BP-cohort 1, n = 65; BP-cohort 2, n = 119), pemphigus vulgaris (PV, n = 67), and pemphigus foliaceus (PF, n = 20) patients. To assess antigen expression, we conducted indirect immunofluorescence (IF) staining of 11 AIBD antigens from 13 anatomical sites of 10 body donors without AIBD. In BP, blisters/erosions and erythematous/urticarial lesions predominantly affected arms and legs, while PV/PF patients exhibited frequent involvement of buccal mucosa and back, respectively. IF staining identified significant regional differences in BP180, BP230, and integrin β4 expression, although these variations did not correlate with a higher lesion frequency/severity. Other antigens showed consistent expression across all regions. Our findings suggest that predilection sites for BP and PV/PF are largely unaffected by regional variations in antigen expression but may be influenced by factors like microbiota, mechanical stress, sunlight exposure, local immunity, or genetics.

Effect of Biomechanical Properties of Perioral Soft Tissues on Lip Response to Simulated Protraction of Upper Front Teeth.

Proclination of front teeth in orthodontics and oral rehabilitation may influence lip protrusion and the overall facial profile. We hypothesized that the degree of profile changes is determined by the biomechanical properties of the lips. (1) to investigate the upper lip changes induced by a simulated protraction of upper front teeth; and (2) to assess the relationship between biomechanical properties of the lips and their response to tooth protraction. Thirty-four participants were recruited at the Faculty of Dentistry, University of Otago, New Zealand. Simulated protraction of upper front teeth was achieved by placing a customised stent covering the buccal surface of the maxillary upper incisors and canines, along with the corresponding buccal mucosa and gingiva. Stereophotogrammetry was used to assess lip changes in three dimensions. Biomechanical properties of the lips, including muscle tone, stiffness and elasticity, were measured using a non-invasive digital palpation device. During the simulated protraction of upper front teeth, the upper lip advanced approximately 50% of the stent thickness, with a considerable inter-individual variation in lip displacement. Soft tissue responses were correlated with the biomechanical properties of the lips with significant correlation coefficients ranging from 0.38 to 0.40. Higher lip tone was associated with increased lip displacement, while greater lip elasticity resulted in reduced lip displacement. Multivariate analyses indicated that upper lip displacement was associated with biomechanical properties and ethnicity, but not with age, sex and body mass index. The response of the lips to protraction of front teeth varies largely between individuals and can be partly explained by variations in the biomechanical properties of perioral muscles.

Sebaceous carcinoma of the intraoral origin: a literature review

Abstract Sebaceous carcinoma (SC) is an aggressive cancer arising from sebaceous glands, rarely occurring in the oral cavity (IOSC). With 21 documented cases, it typically affects the buccal and labial mucosa, tongue, and palate. The cause remains unclear, but Fordyce granules, sebaceous structures in oral mucosa, may play a role in malignancy. IOSC often presents as a painless lump, leading to delayed diagnosis and increased risks of recurrence and metastasis. Early detection and treatment are crucial. Wide local excision (WLE) is the primary treatment, while radiotherapy (RT) is an option for patients unfit for surgery, unwilling to undergo it, or requiring palliative care for advanced cases. RT may also be used pre- or postoperatively to reduce recurrence risks. Cryotherapy and chemotherapy are not standard treatments for IOSC. Regular follow-up is essential for long-term management and to monitor for potential recurrence. The current review provides an updated overview of IOSC, focusing on its clinical presentation, risk factors, pathogenesis, diagnostic approaches, treatment strategies, and prognosis, aims to emphasize the importance of early intervention and a multidisciplinary approach to optimize outcomes.

In vitro cytotoxicity (irritant potency) of toothpaste ingredients.

This study aimed to determine the cytotoxicity (irritant potency) of toothpaste ingredients, of which some had known to have sensitizing properties. From the wide variety of toothpaste ingredients, Xylitol, Propylene glycol (PEG), Sodium metaphosphate (SMP), Lemon, Peppermint, Fluoride, Cinnamon, and Triclosan and Sodium dodecyl sulphate (SDS) have been selected for evaluation of their cytotoxic properties. Reconstructed human gingiva (RHG) were topically exposed to toothpaste ingredients at different concentrations. The compound concentration resulting in 50% cell death (EC50) and 10% cell death (EC10) was determined by the MTT assay. Detrimental effects in tissue histology were observed by hematoxylin & eosin staining of tissue sections followed by microscopy. While Xylitol, PEG, and SMP did not appear to affect cell viability or tissue histology, the concentrations of Lemon, Peppermint, Cinnamon and SDS present in toothpastes exceeded the EC50 value and resulted in clear detrimental effects in tissue histology, indicating that they could harm the oral mucosa. Triclosan and Fluoride concentrations in the tested toothpastes exceeded the EC10 value but remained below the EC50 value with no clear detrimental effects in tissue histology. Manufacturers are encouraged to comply with higher standards of quality and safety for toothpaste.

A Decadal Bibliometric Analysis on the Therapeutic Strategies in Oral Lichen Planus.

Oral Lichen Planus (OLP) is a common chronic inflammatory autoimmune illness that mostly affects the oral mucosa but may also affect other mucous membrane. It has higher prevalence in female patients of fourth to sixth decade of life with reticular being the commonest clinical variant. Clinical assessment, patient history, biopsy findings, and immunofluorescence were used to diagnose OLP. This study aimed to assess research publication trends in therapeutic strategies in the treatment of OLP, examining publication growth, country and institution contributions, and collaborative networks. Using the Dimensions and Lens.org databases with Boolean operators combined the keywords a total of 40,046 peer-reviewed international publications were initially assessed. The article was selected from 2014 to December 2023. Through rigorous application of inclusion and exclusion criteria using an advanced search, a subset of 134 papers emerged to meet the high relevance standards. This subset, constituting a representative sample, was selected for in-depth bibliometric analysis. The result shows a clear upward trend in the number of publications, with a notable increase in 2018. After 2018, there is decrease in the number of publications, but it has an upward trend, reaching a peak of 215 in 2022. Chaitanya Nallan CSK leads the list of authors with four publications and a respectable total citation count of 12. Cairo University is the leading institution in this data set, with the 8 number of publications and 11 citations. The analysis revealed that at the top of the list is the "Egyptian Dental Journal" from Egypt, with six publications, four citations, and a link strength of two. In the second position is "BMC Oral Health" from the United Kingdom, with five publications, one citation, and a link strength of three. This study offers valuable insights for future research, clinical practice, and policy decisions.

Characterization of Buccal Mucosa as Barrier for Drug Absorption; A Mechanistic Study via Solvent Uptake and Model Drug Permeation Studies

Characterization of Buccal Mucosa as Barrier for Drug Absorption; A Mechanistic Study via Solvent Uptake and Model Drug Permeation Studies

Efficacy and potentiality of vitamins and micronutrients oral sprays supplementation (review)

Introduction. Modern pharmaceutical development enables to introduce into practice more than ever new active ingredients delivery systems and forms enhancing actives activity compared to traditional approach (methods). A nowadays pace of life often providing improper feeding and micronutrients intake imbalance leads to necessary administration of micronutrient additional doses in the form of different pharmacies. Over the last years vitamins and minor nutrient elements spray forms are becoming more attractive for introduction into pharmaceutical practice. These dosage forms are characterized by the production availability, usability, easy dosage and sufficiently high bioavailability for both normal patients and ones having gastrointestinal tract diseases and other problems connecting with the food consumption and digestion.Text. Drug delivery by oral mucosa attracts more attention due to its potential advantages compared to other methods. Until recently this administration way was considered mainly for topical application. However, in recent years number of developments connecting with oral cavity application as a portal for delivery of drugs active ingredients, vitamins and micronutrients into systemic blood has kept steadily growing. Diverse forms of oral drugs for sublingual and buccal administration have been developed by many scientific and clinical teams. Spray forms among them are of particular interest as the most economically viable and easy to use. Most of these developments deal with vitamins D and B12, which arises from the acutest problems of their deficiency among global population, on the one hand, and low bioavailability due to negative effects by dietary intake, gastrointestinal tract health condition and other factors, on the other hand. Other micronutrients such as thiamin, niacin, pyridoxin, ascorbic acid, coenzyme Q and iron are examined and launched into the market in an oral spray form for sublingual application.Conclusion. The current results of development and comparison study of micronutrients oral forms, in particular, randomized controlled trial data indicate a sublingual administration efficiency which either is similar to or exceeds traditional administration ways.

Significant risk factors for oral mucosa cancer in the Altai Krai population

Relevance. Squamous cell carcinoma of the head and neck, including oral and oropharyngeal cancer, ranks as the seventh most common cancer worldwide, contributing to over 660,000 new cases and 325,000 deaths annually. Understanding the interplay of adverse factors, their association with disease development, and the creation of mathematical risk prediction models can play a crucial role in enhancing screening efforts and advancing primary prevention of malignant neoplasms.Objective. This study aimed to identify significant risk factors for oral mucosa cancer in the Altai Krai population and to develop a mathematical model for disease risk assessment.Material and methods. The study included 184 patients diagnosed with oral mucosa cancer, along with a control group of 416 healthy volunteers with no history or current diagnosis of oncological diseases. A total of 39 potential risk factors were analyzed across all participants. Statistical analyses were conducted to identify region-specific risk factors for Altai Krai. Binary logistic regression and ROC analysis were used to construct the risk prediction model.Results. Comparative analysis between the patient group and the control group revealed differences in 19 of the 39 evaluated factors. However, the final risk prediction model identified five key factors significantly influencing disease development. Advanced age, smoking status, the number of cigarettes smoked, and alcohol consumption were found to substantially increase the risk of oral mucosa cancer, while engagement in intellectual work-related activities was associated with a reduced risk. The resulting formula demonstrated high predictive accuracy, with an Area Under the ROC Curve (AUC) of 0.91, a standard error of 0.024, and a 95% confidence interval of 0.856–0.955 (z-statistic: 17.50; significance level: P (area = 0.5) < 0.001). Both the sensitivity and specificity of the model were high.Conclusion. The developed risk assessment model shows great promise for helping screen and diagnose oral cancer in the Altai Krai population. This tool could give dentists and healthcare providers a simple, practical way to identify individuals at risk early by using well-established risk factors.

The impact of vapes and electronic cigarettes on the oral mucosa: a literature review

Relevance. Over the past few years, electronic cigarettes have gained popularity as an alternative means of nicotine consumption. In Russia, the number of individuals using vapes has reached 4.2 million. According to studies by Russian addiction specialists, 8.5% of adolescents aged 13–15 in Russia use electronic cigarettes, with prevalence rates of 10.3% among boys and 6.8% among girls. The oral tissues, particularly the mucosa, are the first point of contact with electronic cigarettes, directly exposed to the adverse effects of vape liquid components.Objective. To investigate the effects of vapes on oral health, with a particular focus on the oral mucosa and associated structures.Materials and methods. A total of 37 sources were selected for analysis, including 16 articles from the eLibrary database, 5 from CyberLeninka, and 4 from databases such as Wiley, Taylor & Francis Online, and ScienceDirect. The search was conducted using the query "the impact of vapes on the oral mucosa" and keywords such as "electronic cigarette", "vapes," "oral health," "oral mucosa", and "smoking," in both Russian and English. Preference was given to materials published between 2014 and 2023 that directly addressed the topic, described conducted studies, and provided conclusions. Additionally, a manual search was performed within the reference lists of relevant articles to identify suitable publications.Results. A review of the literature revealed that electronic cigarettes adversely affect oral health, causing irritation of the mucosa and periodontium, salivary gland disorders, demineralization of dental hard tissues, and alterations in the pH of oral fluids.Conclusion. The impact of vapes on oral health remains insufficiently studied. Further experiments and long-term analyses are necessary to more accurately assess the effects of vape chemical components on oral tissues.

Paraneoplastic pemphigus involved oral mucosa only: a case report and literature review

Paraneoplastic pemphigus (PNP) is a rare and potentially fatal autoimmune disease that primarily affects the mucocutaneous tissues. Here we present the clinical features of a patient with the lichenoid variant of PNP involving the oral mucosa only. The patient exhibited clinical manifestations resembling both lichen planus and pemphigus, yet these lesions remained unresponsive to corticosteroid therapy. A chest computed tomography (CT) scan revealed Castleman disease. Following surgical removal of the tumor, the patient’s oral mucosa healed completely, with no recurrence observed in a 4-year follow-up period. These findings emphasize the importance of considering PNP as a potential diagnosis in patients with refractory oral erosions displaying lichen planus-like and pemphigus-like features, particularly when unresponsive to corticosteroid therapy. A thoracic-abdominal-pelvic CT scan is recommended to facilitate accurate diagnosis and appropriate treatment.

Mucoadhesive Drug Delivery System

Mucoadhesive drug delivery systems engage with the mucus layer on the mucosal epithelial surface, interacting with mucin molecules and prolonging the duration of the dosage form at the absorption site. Mucoadhesive drug delivery systems are components of controlled drug delivery systems as well as novel drug delivery systems. Administering drugs through the absorptive mucosa in various readily accessible body cavities such as ocularnasal, buccal, rectal, and vaginal mucosa presents notable benefits compared to peroral administration for systemic effects. Mucoadhesive drug delivery systems extend the duration the dosage form remains at the application or absorption site. They promote close interaction between the dosage form and the underlying absorption surface, thereby enhancing the drug's therapeutic effectiveness.

Bullous Lichen Planus Treated with Adalimumab: A Case Report

Introduction: Bullous lichen planus is a rare variant of lichen planus that is characterized by vesiculo-bullous lesions developing in the setting of pre-existing LP lesions with a burning and painful feeling. Bullous lichen planus treatment is difficult since so few examples of the condition have been documented in the literature. Case Presentation: A 46-year-old female, presented to our outpatient clinic with pruritic violaceous bullae involving lower extremities and oral mucosa for 8 years. After extensive investigations a diagnosis of bullous lichen planus was made and successfully treated with adalimumab after failure of other treatment options. Conclusion: Adalimumab may represent a promising, efficacious, and safe monotherapy option for the management of bullous lichen planus. The therapeutic value of this novel off-label use should be assessed in controlled clinical trials.

Para-Phenylenediamine-Induced Lichenoid Eruption With Involvement of the Oral Mucosa and Subsequent Contact Leukoderma.

Para-Phenylenediamine-Induced Lichenoid Eruption With Involvement of the Oral Mucosa and Subsequent Contact Leukoderma.

The Cell Cycle Regulatory Proteins p16, CDK4, and PTEN Are Unsuitable as Biomarkers in Oral Melanocytic Lesions.

Melanocytic neoplasms are rare in the oral cavity and represent a diagnostic challenge due to the overlap between benign and malignant lesions. However, their pathogenesis is not fully elucidated. The aim of this study was to evaluate the expression of the cell cycle-related proteins p16, CDK4, and PTEN in oral melanocytic nevi and melanomas. A total of 42 cases of melanocytic nevi and five cases of melanoma underwent immunohistochemical analysis. Cases were scored as 0, 1 (< 5% of positive cells), 2 (6%-50% of positive cells), and 3 (> 50% of positive cells). Statistical significance was set at p ≤ 0.05. Two cases of melanocytic nevi were totally negative for p16 and 95.2% of cases scored 1. For CDK4, 47.6% of the cases scored 2 and 52.4% scored 3. For PTEN, 97.6% of the cases scored 3 and only one case showed a score of 2. All melanoma cases were classified with a score of 2 for p16, and for CDK4 and PTEN, all cases exhibited a score of 3. PTEN and CDK4 were higher expressed when compared to p16 both in melanocytic nevi and melanomas (p < 0.001), and melanocytic nevi showed low expression of p16 when compared to melanomas (p < 0.0001). The findings suggest that these cell cycle-related proteins are not useful biomarkers in melanocytic lesions of the oral mucosa and support the apparent biological distinction between oral and cutaneous lesions.