Buccal Gingiva Research Articles

The niche-specialist and age-related oral microbial ecosystem: crosstalk with host immune cells in homeostasis.

Although characterization of the baseline oral microbiota has been discussed, the current literature seems insufficient to draw a definitive conclusion on the interactions between the microbes themselves or with the host. This study focuses on the spatial and temporal characteristics of the oral microbial ecosystem in a mouse model and its crosstalk with host immune cells in homeostasis. The V3V4 regions of the 16S rRNA gene of 20 samples from four niches (tongue, buccal mucosa, keratinized gingiva and hard palate) and 10 samples from two life stages (adult and old) were analysed. Flow cytometry (FCM) was used to investigate the resident immune cells. The niche-specialist and age-related communities, characterized based on the microbiota structure, interspecies communications, microbial functions and interactions with immune cells, were addressed. The phylum Firmicutes was the major component in the oral community. The microbial community profiles at the genus level showed that the relative abundances of the genera Bacteroides , Lactobacillus and Porphyromonas were enriched in the gingiva. The abundance of the genera Streptococcus , Faecalibaculum and Veillonella was increased in palatal samples, while the abundance of Neisseria and Bradyrhizobium was enriched in buccal samples. The genera Corynebacterium , Stenotrophomonas, Streptococcus and Fusobacterium were proportionally enriched in old samples, while Prevotella and Lacobacillus were enriched in adult samples. Network analysis showed that the genus Lactobacillus performed as a central node in the buccal module, while in the gingiva module, the central nodes were Nesterenkonia and Hydrogenophilus . FCM showed that the proportion of Th1 cells in the tongue samples (38.18 % [27.03–49.34 %]) (mean [range]) was the highest. The proportion of γδT cells in the buccal mucosa (25.82 % [22.1–29.54 %]) and gingiva (20.42 % [18.31–22.53 %]) samples was higher (P<0.01) than those in the palate (14.18 % [11.69–16.67 %]) and tongue (9.38 % [5.38–13.37 %] samples. The proportion of Th2 (31.3 % [16.16–46.44 %]), Th17 (27.06 % [15.76–38.36 %]) and Treg (29.74 % [15.71–43.77 %]) cells in the old samples was higher than that in the adult samples (P<0.01). Further analysis of the interplays between the microbiomes and immune cells indicated that Th1 cells in the adult group, nd Th2, Th17 and Treg cells in the old group were the main immune factors strongly associated with the oral microbiota. For example, Th2, Th17 and Treg cells showed a significantly positive correlation with age-related microorganisms such as Sphingomonas , Streptococcus and Acinetobacter , while Th1 cells showed a negative correlation. Another positive correlation occurred between Th1 cells and several commensal microbiomes such as Lactobacillus , Jeotgalicoccus and Sporosarcina . Th2, Th17 and Treg cells showed the opposite trend. Together, our findings identify the niche-specialist and age-related characteristics of the oral microbial ecosystem and the potential associations between the microbiomes and the mucosal immune cells, providing critical insights into mucosal microbiology.

Sociodemographic and clinical profile of 49 patients with oral lichen planus: a 10-year retrospective study

Considering a few epidemiologic studies which describes clinic and pathologic features and prevalence of oral lichen planus (OLP) in Brazil as well as the importance of such studies in order of health care services plans and to verify changes along the years, the present study aimed to evaluate the sociodemographic and clinical profile of 49 participants diagnosed with OLP during a period of ten years. For the sample selection, the clinical and histopathological criteria for the diagnosis of OLP proposed by the American Academy of Oral and Maxillofacial Pathology were used, except for the criterion “absence of epithelial dysplasia”. Most individuals were female (75.5%; p = 0.0005). White individuals were significantly older than the black individuals (67.7 vs 49.2 years; p = 0.001). Lesions affecting multiple bilateral/symmetric sites were more common than lesions in a single bilateral/symmetric site (77.6%; p = 0.0001). The most commonly affected sites were buccal mucosa (85.7%), tongue (65.3%), gingiva (42.9%), and lips (32.7%). Most lesions were white (reticular pattern was found in 93.9% and plaque in 75.5% of cases). Plaque pattern was more common in older individuals (p = 0.006). During the different moments of evaluations some individuals did not meet the American Academy of Oral and Maxillofacial Pathology criteria due to the absence of oral lesions with multifocal symmetric distribution. Therefore, in a first consultation, if the patient does not present multifocal symmetric distributed lesions, the diagnosis of OLP cannot be excluded and the patient should be followed-up.

Does dental x-ray cause oral keratosis?

Introduction and Aim: Ionizing radiation in dental imaging technology may cause cytotoxicity by means of changing the buccal mucosa cells and gingiva maturation pattern. Alteration of maturation pattern was often accompanied by increasing anucleated cells number that indicates keratosis. This study aimed to evaluate whether superficial keratosis also occurred after exposure to dental X-ray radiation. Methods: The study samples consisted of 40 participants and were divided into two groups: exposed (patients who came in for taking analog/digital panoramic radiography or cone beam CT) and controlled (no radiography examinations). Each group contained ten individuals. Exfoliative cytology smears have been taken from the gingival and buccal mucosa before (or on day 0 for the control group) and 10 days post-exposure. The Papanicolaou approach was used to stain the cells. The anucleated cells in each glass slide have been then counted. Results: No significant differences (p &gt; 0.05) were observed in anucleated cell numbers between days 0 and 10 in both the controlled and exposed groups. The anucleated cell numbers also confirmed no significant difference between the gingiva and buccal mucosa. Conclusion: Analog/digital panoramic radiography and CBCT exposure do not cause increases in anucleated cell numbers, so keratosis may not occur in patients exposed to dental X-ray radiation.

Significance of Oral Cavity Biopsy in the Diagnosis of Extranodal NK/T-cell Lymphoma, Nasal Type: A Case Report

<h3>Introduction</h3> Extranodal NK/T-cell lymphoma, nasal type (ENKTL) is a rare, but highly aggressive entity. It occurs most commonly in Asia and native populations of Mexico and Central and South America. This case report details the clinical course of a patient who initially presented for work-up of pancytopenia, and was ultimately found to have a diagnosis of Extranodal NK/T-cell Lymphoma. The patient underwent biopsies of multiple sites including the bone marrow, lymph node, tonsil, and buccal gingiva, with the latter biopsy giving the most definitive, unequivocal result. <h3>Clinical Presentation</h3> A 38 year old Asian male presented to the emergency department for pancytopenia and fevers after he was previously found to be anemic with low hemoglobin levels. His physical examination was notable for right tonsillar enlargement with exudate, a white mass on the right palate, sinusitis, and lymphadenopathy. A bone marrow biopsy was performed and diagnosed as EBV lymphoproliferative disorder with T/cytotoxic cell proliferation, and the differential diagnosis included a T/NK cell neoplasm. Subsequent biopsies of a cervical lymph node and the right tonsil were performed with the lymph node being diagnosed as idiopathic multicentric Castleman's disease; EBV-positive, HHV8-negative. As treatment, the patient was started on siltuximab. The necrotic mass on the palate continued to worsen, extending to the maxillary anterior buccal gingiva. Fortunately, after some time, the patient was referred to oral surgery and a biopsy of the right buccal gingiva was performed, revealing the final diagnosis of ENKTL. The patient was diagnosed with stage IV disease, received treatment with the SMILE regimen, underwent a stem cell transplant, and was overall stable 17 months post-transplant. <h3>Conclusion</h3> This case highlights the importance of thorough oral examinations and timely sampling of any lesions present, as these practices can aid in arriving at an accurate diagnosis.

Malignant Transformation of Oral Lichen Planus: A Case Report and Review of Literature

Oral lichen planus (OLP) is a relatively common inflammatory mucocutaneous disease with unknown etiology. The disease affects 0.5 to 2% of the general population with a predilection for females and middle-aged adults. It commonly presents as bilateral symmetrical lesions on the buccal mucosa, dorsal tongue, and gingiva. The two most common subtypes are reticular and erosive forms. According to Gonzales-Moles, the overall malignant transformation rate is 1.1%, with the reported range of 0% to 12.5%. Here, we present a case of OLP transformed into oral squamous cell carcinoma (OSCC). Case: A 58-year-old woman presented with a 19-year history of leukoplakia on the dorsal and ventral tongue and a 9-year history of painful and eroded gums. In 2002, she had a diagnosis of lichen planus with low-grade dysplasia on biopsy. An incisional biopsy of the lesions from the right mandibular buccal gingiva and right dorsal tongue was performed in 2010. The diagnosis was OLP of gingiva and benign verrucous keratosis of the dorsal tongue. The oral lesions were treated and regularly followed up for 2.5 years, and the patient was lost to follow-up for seven years. In 2019, she presented with biopsy-proven invasive poorly differentiated OSCC of the right mandibular gingiva. She underwent a right marginal mandibulectomy, right selective neck dissection, local flap, and teeth extraction. On an 8-month-follow-up, the patient developed a palpable nodule at the base of the right neck, and a level 1 neck node biopsy was positive for metastatic SCC. She had modified radical neck dissection and right mandibular vestibuloplasty. The patient is currently undergoing radiation therapy. The severity and progression of this case highlight the malignant potential of lichen planus and the importance of careful follow-up.

Oral Focal Mucinosis, an uncommon entity: Report of three cases

<h3>Introduction</h3> Oral focal mucinosis (OFM) is a rare soft tissue lesion of unknown etiology and it is considered the oral counterpart of cutaneous focal mucinosis or cutaneous myxoid cyst. The pathogenesis of OFM may be explained by fibroblast overproduction of hyaluronic acid. Clinically, it appears as painless swelling of the same color as the surrounding mucosa. The gingiva is the most common site and the diagnosis is established only by histopathological and immunohistological examination. <h3>Materials and Methods</h3> We present three cases of gingival oral focal mucinosis. Case 1: 40 year-old womatn with painless and slow-growing swelling of two years of evolution at buccal mandibular gingiva, between lateral incisor and canine. The lesion measured 2 cm. and exhibited the same color as the overlying mucosa; there was not radiographic involvement. Case 2: 48 year-old female with a hard palatal swelling. The lesion was sessile, firm, and not color change Case 3: 36 year-old male with a painless and same color as the normal mucosa gingival swelling. The lesion was between central and lateral right incisors, it was sessil and measured 1.5 cm Results In the three cases excisional biopsy was performed and histopathologically they shown the proliferation of elongated and mucinous material in a myxoid matrix. This myxoid stroma was surrounded by collagenous fibrous connective tissue and covered with squamous epithelium. Histochemical staining with Alcian blue was positive in the mucinous areas Conclusions These three cases are significant clinically as well as histopathologically. The lesions clinically mimic an ossifying peripheral fibroma or a fibroma. Thus, the histopathological and histochemical findings with special stains, such as Alcian blue, are determinant to establish the diagnosis of these conditions. Treatment is the complete surgical excision and its recurrence is not reported.

Oral metastasis of pleural sarcomatoid mesothelioma, a rare aggressive variant of mesothelioma and a diagnostic challenge

<h3>Introduction</h3> Malignant mesothelioma is a rare neoplasm that most commonly develops after exposure to asbestos and arises from the serosal cells of the pleura or rarely peritoneum. Various histological subtypes have been recog- nized: epithelioid, sarcomatoid, biphasic-epithelioid, and biphasic-sarcomatoid, with the sarcomatoid variant being a less common, but more aggressive variant. Numerous genetic alterations have been identified in the development and progression of malignant mesothelioma, most notably mutations in tumor suppressor genes, <i>neurofibromatosis type 2 (NF2), BRCA1-associated protein-1 (BAP1),</i>and <i>cyclin-dependent kinase inhibitor 2A/alternative reading frame (CDKN2A/ARF)</i>. Mesothelioma metastasis to the oral cavity is infrequent, with only nineteen cases reported in the literature. Soft tissue involvement of the oral cavity has been reported in the tongue, followed by the mandibu- lar gingiva, and alveolar mucosa. Prognosis for malignant mesothelioma is poor as it is typically unresponsive to conventional chemotherapeutic agents. New targeted therapies are currently in ongoing clinical trials. <h3>Case Findings</h3> An 81-year-old male, undergoing treatment for malignant pleural mesothelioma and with a history of asbestos exposure, presented for evaluation of a raised, necrotic mass on the left posterior mandibular buccal and lingual gingiva. Panoramic radiograph revealed extensive bone loss. The histopathology was that of a sarco- matoid neoplasm. Immunohistochemistry demonstrated positive staining for WT1, cyclin D1, and P53, supporting the diagnosis of metastatic malignant mesothelioma, sarcomatoid variant. Other stains that help to define mesothe- lioma such as CK5/6, calretinin, and D2-40 were negative. Despite equivocal immunostaining results, the diagnosis was further supported by comprehensive genomic analysis with identification of mutated <i>NF2</i>and <i>BAP1</i>tumor sup- pressor genes. <h3>Conclusion</h3> The diagnosis of malignant pleural mesothelioma relies on morphology supplemented with immuno- histochemistry. The diagnosis is challenging, especially so for the sarcomatoid variant, with immunohistochemical staining profiles often being inconsistent. The current case demonstrates the utility of comprehensive genomic analysis in firmly establishing the diagnosis.

Evaluating the Preemptive Analgesic Effect of Photo-biomodulation Therapy on Pain Perception During Local Anesthesia Injection in Children: A Split-mouth Triple-blind Randomized Controlled Clinical Trial.

To evaluate the impact of photobiomodulation therapy (PBMT) on injection pain perception and compare it with a topical oral anesthetic gel. A total of 30 patients of 6 to 9years-old seeking pulpotomy treatment of maxillary secondary primary molars of both sides were considered for this split-mouth triple-blind randomized clinical trial. On one side of the maxilla, the low-level laser (diode laser, 808 nm, 250 mW; 16.25 J; 32.5 J cm-2 ) was irradiated upon the buccal gingiva of the tooth, while a Benzocaine 20% topical anesthetic gel was applied on the other side. A gel with the same taste (strawberry) was applied for the placebo. The Wong-Baker Faces Pain Rating Scale was used to evaluate the injection pain and postoperation pain at two timestamps, 1 h and 24 h after treatment. Patients' heart rate was also evaluated. Paired t, Wilcoxon signed-rank test, McNemar and Friedman tests were used for statistical analyses. Results demonstrated that PBMT could significantly decrease the injection pain perception and heart rate alternations compared to the topical anesthetic gels (P = 0.000). However, no significant differences were documented between the two methods concerning the 1-h (P = 0.26) and 24-h (P = 1.00) postoperation pain. PBMT can be an effective nonpharmacological technique for controlling injection pain.

Double bridle wire technique: A better alternative for mandibular fracture stabilization.

The first documented evidence of splinting teeth to stabilize mandibular fractures dates back to the Greco–Roman period. Bridle wires then, were made of gold/linen threads.[1] The original technique as described by Hippocrates involved placement of a single wire around the teeth adjacent to the fracture, which is followed till date. The technique is a temporary ' first aid' measure aimed at stabilizing the fracture ends by passing a circumdental pre-stretched 26 gauge wire around the necks of one or two teeth on either side of the fracture. Maintaining manual reduction at the alveolus level, the wire ends are twisted and tightened in a clockwise manner to attain stability. This helps alleviate pain due to fracture movement, gives support and protects from further soft tissue damage and muscle cramping.[2] It helps assist in open reduction and internal fixation (ORIF) of mandible fractures by holding the fracture in a reduced position during fixation.[3] Clinically, loosening of the single bridle wires is often noted and can lead to errors in fixation or patient discomfort due to fracture mobility. A double bridle wire technique can provide better stability and maintenance in the reduced position for mandibular fractures. Similar to a single circumdental wire, two wires are passed around one or two teeth adjacent to the fracture site. The operator while maintaining reduction with one hand, tightens one of the wires by pulling it to one direction away from fracture end (similar to a single wire technique). Subsequently, he pulls and tightens the other wire in the opposite direction, again away from the fracture site. Both the wires are equally tightened to maintain minimum force on the fracture site. After equal tightening of both the bridle/tie wires, the twisted ends are cut and turned clockwise to form a small loop so that the buccal gingiva is not damaged [Figures 1 and 2].Figure 1: Fracture before reductionFigure 2: Fracture stabilized with double bridle wiresIn single mandibular fractures this technique can help reinforce stability of the reduction and can sometimes eliminate the need for arch bars. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Gingival plasma cell granuloma: The importance of histological analysis

AbstractPlasma cell granuloma (PCG) is a mucosal condition characterised histologically by a dense aggregation of polyclonal plasma cells. There are limited reports in the literature of the condition affecting the oral mucosa and involvement of the gingival tissues is considered rare. The variable clinical presentation allows for a differential diagnosis of malignant conditions therefore awareness of the characteristics and distinctive histological features are important in avoiding misdiagnosis. We report a rare case of PCG presenting on the buccal gingivae of the posterior mandible, with concurrent mobility of the adjacent tooth, in a middle‐aged female. The clinical presentation of this lesion warranted urgent investigation, however, histological findings of a dense polyclonal plasma cell infiltrate revealed a benign PCG.

Oral lichenoid contact lesions related to dental metal allergy may resolve after allergen removal

Background/ purposeDistinguishing oral lichenoid contact lesions (OLCLs) from oral lichen planus (OLP) is challenging. This study aimed to identify clinicopathological findings to distinguish OLCLs from OLP, and to evaluate the effectiveness of removing metal allergens in the treatment of OLCLs. Materials and methodsThis study retrospectively evaluated 30 patients diagnosed with OLCLs, and 30 age- and sex-matched OLP patients. We also evaluated the effectiveness of removing dental metal containing positive metal allergen, confirmed by skin patch test and metal component analysis in patients with OLCLs. ResultsPalladium and gold were the most common patch test-positive metals observed in the oral cavity of patients with OLCLs. The patients with OLCLs were more likely to present with white type lesions in the buccal mucosa and gingiva than were the patients with OLP (p = 0.030, 0.009, respectively). Overall, 50.0% of patients with OLCLs failed to meet the histopathological diagnostic criteria of OLP. Twenty-three of 24 (95.8%) patients with OLCLs showed a complete or partial improvement after the removal of dental metal. ConclusionThe present findings suggest the importance of a skin patch test and metal component analysis to confirm suspected OLCLs related to dental metal allergy, as these lesions may improve with the removal of the allergy-inducing metal.

Radiographic evaluation of a cross-shaped incision technique for thick-gingiva and thin-gingiva patients treated with implant-supported fixed prosthesis

BackgroundTo evaluate a cross-shaped incision technique for thick-gingiva and thin-gingiva patients treated with implant-supported fixed prosthesis.MethodsTotal 55 patients receiving cross-shaped incision were assigned into thick-gingiva group (29 cases) and thin-gingiva group (26 cases). Follow-up was performed at 3 and 12-month after final restoration.ResultsMesial and distal papilla height was significantly greater in thick-gingiva group than thin-gingiva group at 3 and 12 months, while periodontal depth and crestal marginal bone level around implant had no significant difference between the two groups during follow-up. No case of recession of buccal marginal gingiva was observed in thick-gingiva group. However, the recession of marginal gingiva of buccal aspect of the crown was found in 5 patients (19.2%) with thin-gingiva.ConclusionsThe cross-shaped incision may be applied to reconstruct gingival papillae and avoid the gingival recession in patients with thick-gingiva phenotype.Trial registration This study was registered at ClinicalTrials.gov (registration number NCT04706078, date 12 January 2021, Retrospectively registered).

Fibrous epulis with ossification: a case report and review of the literature

INTRODUCTION: Fibrous epulis with ossifi cation is a type of gingival overgrowth that is occasionally encountered by dental practitioners. It should be managed carefully, with deep understanding of its exacerbating factors, to reduce the risk of gingival recession and recurrence. OBJECTIVE: To report the characteristics and management of a clinical case of fi brous epulis with ossifi cation, in the anterior maxillary region on a young female patient, and present a review of the literature. CASE REPORT: A 14-year-old healthy female patient was referred by her general dentist to the Periodontology clinic at the Faculty of Dentistry, University of Otago, Dunedin, New Zealand, for the treatment of a lesion on the buccal gingiva of her right maxillary lateral incisor. Th e lesion initially presented as an asymptomatic non-healing ulcer, which progressed into a pedunculated swelling over a time frame of eight weeks. Th e management of this lesion involved excisional biopsy using surgical scalpel and diode laser, followed by a strict follow-up protocol and oral hygiene reinforcement. CONCLUSION: Review of this patient showed uneventful healing, with minimal gingival recession and no signs of recurrence. Report from histology found that the lesion was consistent with fi brous epulis with ossifi cation. Th is case highlights on the importance of reviewing ulcerative lesions to ensure complete resolution or facilitate appropriate timely referral.

Biogeography of Bacterial Communities and Specialized Metabolism in Human Aerodigestive Tract Microbiomes.

ABSTRACTThe aerodigestive tract (ADT) is the primary portal through which pathogens and other invading microbes enter the body. As the direct interface with the environment, we hypothesize that the ADT microbiota possess biosynthetic gene clusters (BGCs) for antibiotics and other specialized metabolites to compete with both endogenous and exogenous microbes. From 1,214 bacterial genomes, representing 136 genera and 387 species that colonize the ADT, we identified 3,895 BGCs. To determine the distribution of BGCs and bacteria in different ADT sites, we aligned 1,424 metagenomes, from nine different ADT sites, onto the predicted BGCs. We show that alpha diversity varies across the ADT and that each site is associated with distinct bacterial communities and BGCs. We identify specific BGC families enriched in the buccal mucosa, external naris, gingiva, and tongue dorsum despite these sites harboring closely related bacteria. We reveal BGC enrichment patterns indicative of the ecology at each site. For instance, aryl polyene and resorcinol BGCs are enriched in the gingiva and tongue, which are colonized by many anaerobes. In addition, we find that streptococci colonizing the tongue and cheek possess different ribosomally synthesized and posttranslationally modified peptide BGCs. Finally, we highlight bacterial genera with BGCs but are underexplored for specialized metabolism and demonstrate the bioactivity of Actinomyces against other bacteria, including human pathogens. Together, our results demonstrate that specialized metabolism in the ADT is extensive and that by exploring these microbiomes further, we will better understand the ecology and biogeography of this system and identify new bioactive natural products.IMPORTANCE Bacteria produce specialized metabolites to compete with other microbes. Though the biological activities of many specialized metabolites have been determined, our understanding of their ecology is limited, particularly within the human microbiome. As the aerodigestive tract (ADT) faces the external environment, bacteria colonizing this tract must compete both among themselves and with invading microbes, including human pathogens. We analyzed the genomes of ADT bacteria to identify biosynthetic gene clusters (BGCs) for specialized metabolites. We found that the majority of ADT BGCs are uncharacterized and the metabolites they encode are unknown. We mapped the distribution of BGCs across the ADT and determined that each site is associated with its own distinct bacterial community and BGCs. By further characterizing these BGCs, we will inform our understanding of ecology and biogeography across the ADT, and we may uncover new specialized metabolites, including antibiotics.

The Effects of Cyclosporine and Tacrolimus on Gingiva and Alveolar Bone of Rats

Objective: Cyclosporine A (CsA) and tacrolimus (Tac) are immunosuppressive drugs which is frequently used in organ transplantation. CsA can cause various side effects including gingival overgrowth (GO) and osteopenia. Tac has similar side effects to CsA but with different incidences. The aim of the present study was to evaluate and compare the effects of CsA and Tac on GO and alveolar bone resorption in rats.&#x0D; Methods: Sixty mature male rats were randomly and equally allocated into six groups, as follows: Control-I, Control-II, CsA-I, CsA-II, Tac-I and Tac-II. The Control-I and Control-II groups received, subcutaneously, 1 ml/kg 0.9% NaCl, while the CsA-I and CsA-II groups received 10 mg/kg CsA daily, and the Tac-I and Tac-II groups 1.5 mg/kg Tac daily. The Control-I, CsA-I and Tac-I groups were sacrificed on the 16th day and other groups on the 31st day. Histological and histomorphometric analysis of the buccal gingiva and tartrate-resistant acid phosphatase (TRAP) enzyme histochemistry of the alveolar bone were performed in the right mandibular segment of each animal. &#x0D; Results: GO was significantly greater in the groups administered CsA compared to the other groups (P0.05). CsA caused a significant increase in TRAP positivity (P0.05). &#x0D; Conclusions: Our results showed that Tac does not seem to cause GO and alveolar bone resorption. However, the deleterious side effects of Tac on the gingival tissues of rats may be time-related.

Microvascular Reactivity of Peri-implant Mucosa in Humans: Effect of Abutment Material.

The morphology and histology of the soft tissue around the implant are different from the periodontal tissue, but the difference in the regulation of blood flow is not known. The aim of the study was to compare the resting blood flow and the vasodilatation capacity of the gingiva between implants and teeth. Twenty-six healthy volunteers with single-tooth implants were involved. The implant-borne crown was retained on either a zirconia or titanium abutment. The vasodilatation capacity of the gingiva was assessed by a postocclusive reactive hyperemia test. Blood flow was measured by a laser speckle contrast imager at the buccal gingiva of the implant-borne crown and an analog natural tooth. No significant differences in baseline gingival blood flow were observed between the different abutments and the teeth in either region. The hyperemia after compression was significantly attenuated at the zirconia abutments in all regions during the entire investigation period (20 minutes) compared to the titanium abutments and the teeth. No differences were observed between titanium abutments and the teeth. The resting microcirculation seems to be the same at implants and teeth. However, the vascular reactivity might be disturbed at the zirconia, but not at the titanium, abutment.

Generation and Characterization of Murine Oral Mucosal Organoid Cultures.

The mucous lining covering the inside of our mouth, the oral mucosa, is a highly compartmentalized tissue and can be subdivided into the buccal mucosa, gingiva, lips, palate, and tongue. Its uppermost layer, the oral epithelium, is maintained by adult stem cells throughout life. Proliferation and differentiation of adult epithelial stem cells have been intensively studied using in vivo mouse models as well as two-dimensional (2D) feeder-cell based in vitro models. Complementary to these methods is organoid technology, where adult stem cells are embedded into an extracellular matrix (ECM)-rich hydrogel and provided with a culture medium containing a defined cocktail of growth factors. Under these conditions, adult stem cells proliferate and spontaneously form three-dimensional (3D) cell clusters, the so-called organoids. Organoid cultures were initially established from murine small intestinal epithelial stem cells. However, the method has since been adapted for other epithelial stem cell types. Here, we describe a protocol for the generation and characterization of murine oral mucosal organoid cultures. Primary epithelial cells are isolated from murine tongue tissue, embedded into an ECM hydrogel, and cultured in a medium containing: epidermal growth factor (EGF), R-spondin, and fibroblast growth factor (FGF) 10. Within 7 to 14 days of initial seeding, the resulting organoids can be passaged for further expansion and cryopreservation. We additionally present strategies for the characterization of established organoid cultures via 3D whole-mount imaging and gene-expression analysis. This protocol may serve as a tool to investigate oral epithelial stem cell behavior ex vivo in a reductionist manner.

Oral Squamous Cell Carcinomas in Patient with Graft Versus-Host Disease Following Allogenic Bone Marrow Transplantation: A Case Report during Mutant COVID-19 Pandemic

Aplastic anaemia is a severe haematological disorder characterized by an inadequate number of hematopoietic stem cells, resulting in pancytopenia, formed by a hypocellular bone marrow. Disorders of this nature are widely treated with haematopoietic stem cell transplantation (HSCT). A potential chronic complication following (HSCT) is the growth of secondary malignancies. Notably, patients suffering from chronic graft versus host disease (cGvHD) secondary to HSCT have been shown to be more susceptible to oral squamous cell carcinoma (OSCC). Here, we present a rare case of a 30-year-old Libyan woman treated with HSCT for aplastic anaemia, with subsequent complications of cGvHD and OSCC after few months of HSCT. These carcinomatous lesions were detected in the buccal gingiva and retromolar pad area at the age of 31. The present case report emphasizes the connection between oral cGvHD and OSCC, and the potential appearance of OSCC after HSCT at any time of patient life. Thus, closer follow-up is mandatory for all patients treated with HSCT who developed cGvHD, and efficient cGvHD prevention and therapeutic approaches are needed.

NONSEMINOMATOUS GERM CELL TUMOR METASTATIC TO THE MAXILLA

<h3>Background</h3> Extragonodal germ cell tumors (GCTs) primarily affect the sacrococcygeal region. Head and neck GCT is rare and accounts for 3% of pediatric neoplasms. Only isolated cases of metastatic GCT have been reported. <h3>Objective</h3> To report a unique case of a metastatic nonseminomatous GCT of mixed phenotype with yolk sac tumor, embryonal carcinoma, and immature teratoma components. <h3>Clinical Findings</h3> A 13-year-old male patient presented with a rapidly enlarging, painless right maxillary tuberosity mass, present for 4 months. The tumor was on the buccal gingiva extending to the hard and soft palate posteriorly. Ipsilateral submandibular lymphadenopathy was evident. No pathology was noted on the panelipse and periapical radiographs. The clinical impression was that of a lymphoma or Kaposi sarcoma. <h3>Pathologic Findings</h3> The histology showed an extensively infiltrative high-grade malignancy composed of small, round, blue discohesive tumor cells demonstrating a solid growth pattern, with areas of adenocarcinoma and squamous differentiation with keratinization. Surface dysplasia was not present. Brisk mitotic activity was noted. Immunohistochemistry revealed positivity with for AE1/AE3, SALL4, Glyplican 3, and OCT3/4, confirming the diagnosis of a metastatic nonseminomatous GCT of mixed phenotype. <h3>Summary</h3> Benign teratomas are the most common childhood extragonodal tumors, followed by yolk sac tumors, which frequently arise in the ovaries and testis. Yolk sac tumors that frequently arise in the ovaries and testis have been reported but continue to be a rare extragonodal tumor and are difficult to diagnose. This report reviews germ cell tumors in the spectrum of metastatic disease to the oral cavity.

Distribution and determinants of submandibular gland involvement in oral cavity squamous cell carcinoma

IntroductionThough the submandibular gland (SMG) is routinely sacrificed for several reasons during neck dissection in patients undergoing curative surgery for oral cavity cancers, it might be an innocent bystander and should be considered for preservation. This study aimed to identify the incidence, different patterns of invasion, and risk factors of SMG involvement in oral cavity squamous cell carcinoma (SCC). MethodsThis was a retrospective study of the patients who underwent upfront curative surgery for a biopsy-proven oral cavity SCC. A consistent protocol-based treatment strategy was followed during the study period. Data about clinical profile including demographics, clinical and histology details, and treatment profile were extracted and analysed. ResultsA total of 303 patients underwent unilateral and bilateral neck dissections contributing 79.2% (n = 240) and 20.8% (n = 63) of patients respectively. The common primary sites were buccal mucosa (n = 129, 42.5%), tongue (n = 100, 33.0%) and alveolar gingiva (n = 52, 17.2%). A total of four SMGs showed tumor involvement resulting in a prevalence of 1.09% per neck dissection (n = 366) and 1.32% per patient (n = 303). Of these four cases of SMG involvement, one patient with alveolar cancer had direct tumor invasion while the other three (alveolar cancer – two, tongue cancer – one) patients had neck node metastasis. ConclusionThe present study confirms a very low incidence of SMG involvement in patients with oral cavity cancer who undergo neck dissection. It is often observed in patients with high neck node burden (≥N2 disease and the presence of extracapsular spread) or direct invasion by the primary tumor.