Oral Mucosal Sites Research Articles

Clinico-pathological specificities of gingival carcinoma among 32 patients with oral cancer: a cross sectional retrospective and observational study

BackgroundThe study aimed to examine the prevalence of gingival cancers compared to other oral mucosal sites, analyze patient profiles, and identify risk factors.Materials and MethodsA retrospective monocentric study was conducted at the Department of Oral Medicine of Bretonneau Hospital in Paris, France. 32 patients diagnosed with oral mucosal cancer were included. Data extracted from electronic medical records encompassed patient demographics, cancer type, lesion location, and tobacco/alcohol use.Results46.9% were diagnosed with gingival cancer. Patients with gingival cancer had a mean age of 74.2 years old, higher than the mean age of 63.9 years old for those with non-gingival cancer. Men accounted for 60% of cases in the gingival cancer group. Squamous cell carcinoma was the predominant cancer type observed in both gingival and non-gingival cancers. Notably, 26.7% of gingival cancer patients used both alcohol and tobacco, all of them male. Among non-gingival cancer patients, 23.5% used both substances, with both sexes represented.ConclusionThis study provides insights into the higher prevalence of oral squamous cell carcinoma among men with risk factors and highlights characteristics of gingival squamous cell carcinoma. Effective management strategies should include comprehensive clinical assessments to ensure early detection and intervention for improved outcomes.

Geographic Stomatitis with Multiple Areas Involvement of Oral Cavity: A Case Report and Review of Literatures

Background: Geographic stomatitis is an uncommon migratory benign lesion of oral mucosa with unknown etiology. It can affect all the areas of the oral mucosa, but the dorsum and lateral borders of the tongue are the most commonly involved areas called geographic tongue. The clinical appearance of this condition is the oval or circular erythematous areas with irregular elevated keratotic borders. These characteristic features of geographic stomatitis are diagnostic for all clinicians when appearing on the dorsum of the tongue, despite other affected areas of oral mucosa that can confuse clinicians. This condition may be associated with some diseases such as psoriasis, Reiter’s syndrome, and atopic conditions, so the clinicians should rule out these diseases and diagnose the geographic stomatitis. Case Report: A 17-year-old male attended to our department for a routine dentistry checkup. During the intraoral examination, we found multiple erythematous areas surrounded by a thin white border on different surfaces of his oral cavity. His extraoral examinations were completely normal. Conclusion: Due to the rarity of this lesion on the other sites of oral mucosa rather than dorsum and lateral borders of the tongue such as labial mucosa, buccal mucosa, the floor of the mouth, ventral surface of the tongue, and palate, it is necessary to report, study and evaluate each case of this condition that clinicopathologic findings have confirmed this diagnosis, to treat and advice these patients on the best approach. [GMJ.2021;10:e2071]

Full-body skin examination in screening for cutaneous malignancy: a focus on concealed sites and the practices of Australian dermatologists.

Full-body skin examination (FSE) is a vital practice in the diagnosis of cutaneous malignancy. Precisely how FSE should be conducted with respect to concealed site inclusion remains poorly elucidated. To establish the approach of Australian dermatologists to concealed site examination (CSE). A cross-sectional study was performed consisting of an online self-administered 11-question survey delivered to fellows of the Australasian College of Dermatologists. There were 237 respondents. Anogenitalia was the least often examined concealed site (4.6%), and 59.9, 32.9, and 14.3% reported always examining the scalp, breasts, and oral mucosa, respectively. Patient concern was the most frequently cited factor prompting examination, while many cited low incidence of pathology and limited chaperone availability as the main barriers to routine examination of these sites. Most Australian dermatologists do not routinely examine breasts, oral mucosal, or anogenital sites as part of an FSE. Emphasis should be made on identifying individual patient risk factors and education regarding self-examination of sensitive sites. Aconsensus approach to the conduct of the FSE, including concealed sites, is needed to better delineate clinician responsibilities and address medicolegal implications.

Clotrimazole-Loaded Borneol-Based In Situ Forming Gel as Oral Sprays for Oropharyngeal Candidiasis Therapy.

Oral candidiasis encompasses fungal infections of the tongue and other oral mucosal sites with fungal overgrowth and its invasion of superficial oral tissues. Borneol was assessed in this research as the matrix-forming agent of clotrimazole-loaded in situ forming gel (ISG) comprising clove oil as the co-active agent and N-methyl pyrrolidone (NMP) as a solvent. Their physicochemical properties, including pH, density, viscosity, surface tension, contact angle, water tolerance, gel formation, and drug release/permeation, were determined. Their antimicrobial activities were tested using agar cup diffusion. The pH values of clotrimazole-loaded borneol-based ISGs were in the range of 5.59-6.61, which are close to the pH of 6.8 of saliva. Increasing the borneol content in the formulation slightly decreased the density, surface tension, water tolerance, and spray angle but increased the viscosity and gel formation. The borneol matrix formation from NMP removal promoted a significantly (p < 0.05) higher contact angle of the borneol-loaded ISGs on agarose gel and porcine buccal mucosa than those of all borneol-free solutions. Clotrimazole-loaded ISG containing 40% borneol demonstrated appropriate physicochemical properties and rapid gel formation at microscopic and macroscopic levels. In addition, it prolonged drug release with a maximum flux of 370 µg·cm-2 at 2 days. The borneol matrix generated from this ISG obsentively controlled the drug penetration through the porcine buccal membrane. Most clotrimazole amounts still remained in formulation at the donor part and then the buccal membrane and receiving medium, repectively. Therefore, the borneol matrix extended the drug release and penetration through the buccal membrane efficiently. Some accumulated clotrimazole in tissue should exhibit its potential antifugal activity against microbes invading the host tissue. The other predominant drug release into the saliva of the oral cavity should influence the pathogen of oropharyngeal candidiasis. Clotrimazole-loaded ISG demonstrated efficacious inhibition of growth against S. aureus, E. coli, C. albicans, C. krusei, C. Lusitaniae, and C. tropicalis. Consequently, the clotrimazole-loaded ISG exhibited great potential as a drug delivery system for oropharyngeal candidiasis treatment by localized spraying.

Geographic Stomatitis with Multiple Areas Involvement of Oral Cavity: A Case Report and Review of Literatures.

Background:Geographic stomatitis is an uncommon migratory benign lesion of oral mucosa with unknown etiology. It can affect all the areas of the oral mucosa, but the dorsum and lateral borders of the tongue are the most commonly involved areas called geographic tongue. The clinical appearance of this condition is the oval or circular erythematous areas with irregular elevated keratotic borders. These characteristic features of geographic stomatitis are diagnostic for all clinicians when appearing on the dorsum of the tongue, despite other affected areas of oral mucosa that can confuse clinicians. This condition may be associated with some diseases such as psoriasis, Reiter’s syndrome, and atopic conditions, so the clinicians should rule out these diseases and diagnose the geographic stomatitis.Case Report:A 17-year-old male attended to our department for a routine dentistry checkup. During the intraoral examination, we found multiple erythematous areas surrounded by a thin white border on different surfaces of his oral cavity. His extraoral examinations were completely normal.Conclusion:Due to the rarity of this lesion on the other sites of oral mucosa rather than dorsum and lateral borders of the tongue such as labial mucosa, buccal mucosa, the floor of the mouth, ventral surface of the tongue, and palate, it is necessary to report, study and evaluate each case of this condition that clinicopathologic findings have confirmed this diagnosis, to treat and advice these patients on the best approach.

Oral candidiasis and the risk factors: a serial case reports

Oral candidiasis (OC) is also referred as ‘thrush’ is caused by the infections of the tongue and other oral mucosal sites and characterized by fungal overgrowth and invasion of superficial tissues. The main causative agent of 95% OC cases is Candida albicans. The prevalence of fungal oral infection was increased due to the increasing use of antibiotic and immunodeficiency condition. However, many factors have been suggested as risk factors for oral colonization. These predisposing factors are divided into local and systemic factors. We present two cases of patient with oral candidiasis that have admitted at Wangaya Regional Hospital, Denpasar, Bali, Indonesia with different precipitating factors in order to remind health provider that oral candidiasis does not only occur in people living with HIV/AIDS (PLWHA).

SYNCHRONICITY OF ORAL LICHEN PLANUS AND MUCOEPIDERMOID CARCINOMA OF MINOR SALIVARY GLAND. CASE REPORT

Background Oral lichen planus is a disease of unknown origin, although its etiology associated with immune disorders is favored. It is difficult to control and has distinctive clinical characteristics that mainly affect vestibular mucosa among other oral mucosa sites. On the other hand, mucoepidermoid carcinoma is the most common malignant neoplasm of minor salivary glands, appearing mainly on the palate. In labial mucosa it can appear as nodules of slow growth, asymptomatic and with blue coloration. A case is reported where both entities are diagnosed in the same patient. Case Presentation A 53-year-old female patient presented with reticular lesions and white plaques with erosive areas distributed in almost all oral mucosa and vermilion borders, with 1 year of evolution that has worsened over time without diminishing over various treatments. On examination, a mobile firm nodule, 1.0 cm in diameter, was distinguished in the submucosal aspect of the lower left labial mucosa. Upon interrogation, the patient was referred for a surgical procedure a year and a half ago without obtaining a histopathologic diagnosis. Biopsies were indicated in both processes. Oral lichen planus and CM of the labial lesion were corroborated by microscopy. Treatment with topical steroids and monitoring of the surgical site of labial mucosa was indicated. After 1-year follow-up, there was control of oral lichen planus and no recurrence of CM. Conclusions The importance of extra- and intraoral examination is based on the various clinical diagnoses found in patients because they can be unique and multiple, with the latter independent or dependent on each other with better treatment and prognosis opportunities.

Patterns of oral mucositis in advanced oral squamous cell carcinoma patients managed with prophylactic photobiomodulation therapy-insights for future protocol development.

To characterize oral sites affected by radiation-induced oral mucositis (OM) and related clinical outcomes in oral cancer patients subjected to prophylactic photobiomodulation therapy (PBMT). This study included advanced oral squamous cell carcinoma (OSCC) patients treated with prophylactic PBMT for OM. The site distribution of OM, OM grading (CTCAE NCI, Version 4.0, 2010), OM-related pain (VAS), analgesic protocol (WHO Analgesic Ladder), and use of enteral nutrition were evaluated weekly during treatment. Data analysis was performed using descriptive statistics expressed as median values and percentages. A total of 145 OSCC patients were included. OM most frequently affected the lateral border of the tongue (44.1%), buccal mucosa (37.2%), and labial mucosa (33.8%). Keratinized oral mucosa sites, including the tongue dorsum (6.21%), retromolar trigone (8.3%), and hard palate (2.76%), were less frequently affected. Peak OM scores were observed at weeks 5, 6, and 7, with severe OM (NCI grades 3 and 4) rates of 11%, 20%, and 25%, respectively. The cumulative occurrence of severe OM was 23%, which developed as early as week 3 and as late as week 7. The highest mean value of OM-related pain (2.7) was observed at the sixth week, and 13.8% of the patients required feeding support. This study showed, compared with studies that did not provide PBMT, reduced severity of mucositis, reduced pain and analgesic use, and reduced tube feeding in patients treated with PBMT. OM involving keratinized and non-keratinized surfaces should be included in the prophylactic PBMT to reduce severe OM in future studies.

The microbiome and rheumatoid arthritis.

Rheumatoid Arthritis (RA) is a severe, chronic autoimmune disease that affects 1% of the world's population. Familial risk contributes 50% of the risk of seropositive RA, with strongest risks seen in first-degree relatives. Smoking increases the risk of developing anti-citrullinated peptide antibody (ACPA)+ RA, particularly in individuals with high-risk RA-susceptibility alleles. Other contributory environmental risks including particulate exposure, periodontal disease, bronchiectasis, diet, obesity and the oral contraceptive impact respiratory, oral, intestinal and genital tract mucosal sites. Furthermore, the first signs of autoimmunity may appear at mucosal sites e.g. sputum ACPA-IgA and IgG. While oral and faecal dysbiosis are well described, there is no consistent single bacterial species that appears to drive RA. Animal and human data suggest a model in which multiple environmental influences impact mucosal immune function through the host genetics through enhanced mucosal permeability and the traffic of pro-inflammatory PAMPs and the amplification of autoimmune responses. In some cases, autoimmunity may be driven by cross-reactivity, or mimicry, to pathogen-specific antigens, particularly where the host immune system fails to support their rapid control and elimination.

Interobserver and intraobserver variability affecting the assessment of loss of autofluorescence of oral mucosal lesions.

The assessment of loss of tissue autofluorescence (LAF) has been proposed as an adjunct to comprehensive oral examination to enhance the detection of mucosal lesions harbouring dysplasia or carcinoma. The assessment of LAF is not based on completely objectified parameters therefore intraobserver and interobserver variability cannot be neglected alongside the issue of correct interpretation of LAF. The present study evaluated intraobserver and interobserver variability in the clinical assessment of LAF as performed by oral medicine practitioners (OMPs) or general dental practitioners (GDPs). Couples of clinical pictures, acquired under white incandescent dental operatory light and during the assessment of LAF performed by VELscope were retrieved. Four OMPs and eight GDPs were asked to assess the pictures and to score the LAF. Kappa statistics allowed the assessment of intra- and inter-observer related variability. Pictures of 109 lesions representative of all oral mucosal sites and clinical appearances were selected. OMPs had a better intraobserver agreement than GDPs (substantial versus moderate). The moderate (k = 0.506) interobserver agreement observed among both OMPs and GDPs in a 2-score model (positive versus negative), lowered down to poor values only among GDPs when a 3-score or 4-score model (including uncertain judgements) was applied. A good agreement (k>0.8) was never observed and the present results are similar to previously reported data about conventional oral examination. Irrespective of the diagnostic accuracy, the assessment of AF seems not to be able to improve observer-related variability in the clinical assessment of oral mucosal lesions.

The underestimated problem of oral Candida colonization-An observational pilot study in one nursing home.

ObjectivesOlder people are at increased risk of intraoral yeast colonization. In this observational case series, we assessed Candida colonization among nine nursing home residents to investigate possible correlations with their individual characteristics, general health parameters, and oral care. We also described the effect of professional dental cleaning (PDC) including prosthesis cleaning on colonization cases.Materials and methodsGeneral clinical and oral health was assessed in nine residents, and samples were taken from six oral mucosa sites or prosthetic surfaces. PDC was performed to achieve macroscopically clean results, and residents were re‐examined 2 weeks later.ResultsWe found that six residents were intraorally colonized with Candida albicans; four also had Candida glabrata. Prostheses were particularly infected. Dementia, multimorbidity, and presence of prostheses reduced oral hygiene ability; requiring assistance for oral hygiene care was a risk indicator for Candida colonization. PDC reduced C. albicans (at the expense of increased C. glabrata) but was not optimal for maintaining Candida reduction.ConclusionIn this pilot study, Candida colonization is prevalent among nursing home residents, especially those with cognitive impairment, multimorbidity, or reduced oral hygiene capacity. Potential negative effects on general health necessitate diagnostic and therapeutic guidelines. PDC alone did not maintain the reduction in Candida colonization; additional methods for daily oral care are necessary.

Microbiomic differences at cancer-prone oral mucosa sites with marijuana usage

Marijuana smoke contains cannabinoids, immunosuppressants, and a mixture of potentially-mutagenic chemicals. In addition to systemic disease, it is thought to contribute to oral disease, such as tooth loss, tissue changes in the gums and throat, and possibly oral pharyngeal cancer. We used a cross-sectional study of 20 marijuana users and 19 control non-users, to determine if chronic inhalation-based exposure to marijuana was associated with a distinct oral microbiota at the two most common sites of head and neck squamous cell carcinoma (HNSCC), the lateral border of the tongue and the oral pharynx. At the tongue site, genera earlier shown to be enriched on HNSCC mucosa, Capnocytophaga, Fusobacterium, and Porphyromonas, were at low levels in marijuana users, while Rothia, which is found at depressed levels on HNSCC mucosa, was high. At the oral pharynx site, differences in bacteria were distinct, with higher levels of Selenomonas and lower levels of Streptococcus which is what is seen in HNSCC. No evidence was seen for a contribution of marijuana product contaminating bacteria to these differences. This study revealed differences in the surface oral mucosal microbiota with frequent smoking of marijuana.

Effects of menthol-flavored substances at the cellular level on oral mucosal sites

The purpose of this study was to determine the effects of menthol-flavored substances at the cellular level in different mucosal sites of the oral cavity and to compare the cellular changes between individuals without the habit of chewing menthol-flavored substances and individuals with the habit. This was an experimental cytology study including a total of 500 individuals belonging to the age group of 18-45 years based on the inclusion or exclusion criteria. The selected participants were divided into two groups of 250 participants each, based on participants not having the habit of chewing menthol-flavored substances (Group I) and participants having the habit of chewing menthol-flavored substances (Group II). Cytological smears were taken by gently scraping the mucosal surfaces in different sites of the oral mucosa using a wooden spatula and stained with Papanicolaou, analyzed under microscope for any cellular changes. The results were tabulated and statistically analyzed using Chi-square test and Fisher's exact test. P < 0.05 was considered statistically significant. Micronuclei seen in all the participants belonging to group with the habit of chewing menthol-flavored substances with a P < 0.001 which was considered highly significant. Alteration in the nuclear-cytoplasmic ratio was also seen P = 0.001, which showed significant at 1% significance level. Participants with habit of chewing menthol-flavored substances showed the presence of micronuclei and slight alteration in the nuclear-cytoplasmic ratio, which could be directly related to genotoxicity and cell damage.

Evaluation of an innovative oral brush for potential applications using liquid based cytology.

The present study was conducted to assess the applicability of liquid-based cytology (LBC) using an innovative oral brush, Orcellex. Fifty healthy volunteers were recruited. From each subject, four samples were collected using "Orcellex" from apparently normal oral mucosal sites. A plastic spatula was also used to obtain an additional sample. Data on the tolerability and acceptability of the Orcellex were collected from the subjects, together with assessments of the adequacy of LBC slide preparations for cellularity, preparation quality, and the types of cells observed. The Orcellex brush was well accepted by the volunteers, who reported relatively little pain. Orcellex brush LBC preparations were of good quality in terms of cell morphology and staining, with a clean background. Only two smears (2/200; 1%) were found to be inadequate due to low cellularity. All of the plastic spatula LBC preparations were inadequate. Representative cells from all layers of the different oral epithelia examined were documented. Oral liquid-based cytology using the Orcellex brush may have considerable potential for early detection of oral cancer and precancer.

Hypermethylated ZNF582 and PAX1 genes in oral scrapings collected from cancer-adjacent normal oral mucosal sites are associated with aggressive progression and poor prognosis of oral cancer

ObjectiveThis study assessed whether hypermethylated ZNF582 and PAX1 genes in oral scrapings are correlated with the progression and prognosis of oral squamous cell carcinoma (OSCC). Materials and methodsMethylation levels of ZNF582 and PAX1 genes in oral scrapings, collected from the cancer and adjacent normal oral mucosal sites of 80 OSCC patients before surgical cancer excision, were quantified using real-time methylation-specific PCR after bisulfite conversion. ResultsBoth the mean methylation (M)-indices of ZNF582 and PAX1 genes in oral scrapings were significantly higher at the cancer sites than at the adjacent normal oral mucosal sites (both P < .001). In the oral scrapings collected from the adjacent normal oral mucosal sites, the higher M-index of methylated ZNF582 (ZNF582m) was significantly correlated with a more advanced clinical stage (P = .04). Moreover, the higher M-index of methylated PAX1 (PAX1m) was significantly related to larger tumor size (P = .046). When the 80 OSCC patients were classified based on gene methylation tests, using the oral scrapings collected from the adjacent normal oral mucosal sites, we found a significantly shorter 3-year overall survival in ZNF582m-positive, PAX1m-positive, and ZNF582m/PAX1m-positive OSCC patients than in ZNF582m-negative (P = .02), PAX1m-negative (P = .04), and ZNF582m/PAX1m-negative OSCC patients (P = .02), respectively. Multivariate Cox regression analyses identified ZNF582m and ZNF582m/PAX1m as independent unfavorable prognostic factors. ConclusionHypermethylated ZNF582 and PAX1 genes in the oral scrapings collected from adjacent normal oral mucosal sites rather than cancer sites are associated with aggressive progression and poor prognosis of OSCC.

Physiological oral melanin pigmentation in a South African sample: A clinical study.

Physiological oral melanin pigmentation is genetically determined, more frequently affecting people with darker skin. It can involve any oral mucosal site, but predominantly the gingiva. The aim of the present study was to determine the prevalence and to characterize the clinical features of physiological oral melanin pigmentation in a South African population sample. A trainee in the discipline of periodontology and oral medicine interviewed all participants and examined the oral soft tissues. The diagnosis of physiological oral melanin pigmentation was based on clinical findings and on the history reported by the patient. A predetermined list of exclusion criteria was applied. The study population comprised 430 participants, of whom 319 (74%) were black, 55 (13%) Indian, 54 (12.5%) white, and two (0.5%) were mixed race. A total of 182 participants were diagnosed with physiological oral melanin pigmentation. The overall prevalence of physiological oral melanin pigmentation in the ethnically-mixed study population was 42%: 54% of blacks were affected, 16% of Indians, and 21% of whites. The female (101): male (81) ratio was 1.2:1; the gingiva was the site most frequently affected (73%). The total number of oral mucosal sites with physiological oral melanin pigmentation in the study population was 263; 68% of participants had one, 22% had two, 7% had three, and 3% had four sites affected. There was no significant association between the number of sites affected and sex or age. In this study of a South African population sample, the prevalence of physiological oral melanin pigmentation was higher in blacks than in Indians or whites, and the gingiva was the oral mucosal site most frequently affected.

Clinical Epidemiological Study of Oral Pre-cancer and Cancer in a Tertiary/Referral Hospital

Abstract Aim: To study the prevalence of oral cancer in patients reported to the Department of Oral Medicine and Radiology, Tamil Nadu Government Dental College and Hospital. Materials and Methods: After selecting the patients with the clinical criteria the history of the habits, duration in months and frequency per day, duration of the symptoms, oral mucosal site involvement, lymph node involvement, associated with lesions were recorded in a structured proforma. Incisional biopsy under Local anaesthesia and histological examination was performed. The results obtained were analysed statistically. Results: 200 patients were diagnosed with oral cancer, 49% were male and 51% were females. In that 51(25%) were associated with premalignant lesions, 94 had only one habit, 74 had a combination of habits, 40% were histopathologically moderately differentiated followed by 33% poorly differentiated and 27% well differentiated. And patients with stage III (31%) and IV (43%) were reported predominantly than stage I (12%) and II (14%). Conclusion: Early diagnosis and intervention prevent the progression of oral cancer.

Crosstalk between Mind and Oral Cavity: An Insight into Pathogenesis, Classification, Presentation and Management of Oral Psychosomatic Disorders

In general, the conviction is that psychological factors are important in the development of all disease. Epidemiological surveys have revealed that there are different ways in which emotional stressful stimuli can act on oral mucosal target sites. Whether their role is in initiation, progression, aggravation or exacerbation of disease or in predisposition or reaction to a disease is still not clear. Based on available evidences, a need for the understanding of oral psychosomatic disturbances is felt. This review summarizes the underlying pathophysiology of bodily changes brought about by stress related psychosomatic mechanism and their role in further development of structural changes seen in association with oral cavity. An effort has also been made to realize the significant

Candida parapsilosis Sensu Stricto: A Common Colonizing in Oral Mucosa of Argentine Subjects

Candida parapsilosis is a complex made up of three species (Candida parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis) which differ genetically. In Argentina and worldwide, no data is available on the distribution and behavior of the complex in oral cavity niches, and there is little information on its epidemiology. Aim: To characterize Argentine isolates of the C. parapsilosis complex from different oral cavity sites and other ecological niches. Methodology: Retrospective, cross-sectional, descriptive study on a collection of isolates which were previously identified by conventional methods as parapsilosis complex, in order to distinguish the species by using end-point PCR with specific primers derived from a single sequence in the ITS1-5.8SrRNA-ITS2 region. Results: 95% of the isolates were identified as Cp. sensu stricto, which was recovered with higher probability from oral mucosa sites, under pathological conditions, and in presence of intraoral appliances. Seventy-four percent of the strains were recovered under conditions of immunocompetence, and 100% of the isolates had resistant phenotype to flucytosine. Conclusions: C. parapsilosis sensu stricto is a common species in different ecological niches. It is more likely to be recovered under conditions of immunocompetence. Dysbiosis of the mouth favors the growth of Cp. sensu stricto, which under these conditions may become a source for cross-transmission of more or less virulent strains by direct person-to-person contact, and a potential source of candidemia or invasive infections through hematogenous dissemination of strains with increased pathogenicity.

Evaluation of different pig oral mucosa sites as permeability barrier models for drug permeation studies

The objective of the present study was to investigate the influence of preparation and storage conditions on the histology and permeability of different parts of porcine oral mucosa used for in vitro studies of transbuccal formulations. Fresh and frozen (−20°C and −80°C, with or without cryoprotectant) epithelia of porcine palatal, gingival, dorsum of the tongue, and buccal mucosa were submitted for histological analyses to determine the effects of storage conditions on barrier integrity. Permeation of lidocaine hydrochloride (used as a hydrophilic model drug) across fresh and previously frozen oral epithelium was measured in order to evaluate the barrier function. Histological evaluation demonstrated that the oral epithelium was successfully separated from the connective tissue, except for gingival mucosa. After storage under different conditions, all tissues presented desquamation of superficial layers and spherical spaces induced by the freezing process. The permeability of lidocaine hydrochloride varied among the fresh oral mucosa and generally increased after freezing. In conclusion, fresh epithelium from the buccal and dorsum of the tongue mucosa should be used for in vitro studies investigating hydrophilic drug transport when these are the desired clinical application sites. However, when the palate is the target site, both fresh and frozen (for up to 4weeks, without addition of cryoprotectant) samples could be used. The addition of glycerol as a cryoprotectant should be avoided due to increased lidocaine hydrochloride permeability.