[A Case of Maxillary Gingival Carcinoma Possibly Caused by Chronic Inflammation Related to Oral Candidiasis].

Oral candidiasis infection is generally treated with antifungal agents. However, it often requires long-term treatment, and epithelial dysplasia may persist even after the infection has been resolved depending on the case. Malignant transformation has been reported in long-term cases involving chronic inflammation, and surgical excision should be performed as the treatment of choice when the treatment period is prolonged. This report describes a case of maxillary gingival carcinoma caused by chronic inflammation related to oral candidiasis. The patient was an 85-year-old man who was admitted to our hospital with maxillary gingival pain. Cytology and biopsy revealed oral candidiasis and squamous cell carcinoma(cT1N0M0, Stage Ⅰ). He underwent partial maxillectomy. Post-operative recovery was uneventful, and there was no sign of recurrence or metastasis at the 1-year follow-up.

[Clinicopathological Study of the Resected Oral Leukoplakia Cases].

Oral leukoplakia is the most common premalignant or potentially malignant lesion in the oral mucosa. This retrospective study examined 67 lesions from 62 patients with clinical diagnoses of oral leukoplakia who underwent surgical excision in our department from 2015 to 2017. The patients comprised 22 men and 40 women. The most common location of the lesion was the lower gingiva, followed by the tongue, upper gingiva, buccal mucosa, palate, and lip. The most common clinical type was the white-spotted, followed by erythroleukoplakia, hillock, and verrucous types. Histopathologically, 16 lesions were oral intraepithelial neoplasia, whereas five were squamous cell carcinoma. The data identified several characteristics of oral leukoplakia that predict a high risk of malignant transformation and require aggressive surgical resection.

Oral Mucosa Could Be an Infectious Target of SARS-CoV-2.

The World Health Organization reported that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission is caused by respiratory droplets and aerosols from the oral cavity of infected patients. The angiotensin-converting enzyme 2 (ACE2) is considered the host functional protein for SARS-CoV-2 infection. In this article, we first revealed that the positive proportion of ACE2 expression in gingival cells collected from the gingival sulcus was increased to the same level as the tongue. Our data demonstrate that cells in the gingival sulcus may be a new entry point for the SARS-CoV-2 virus via a high expression of ACE2. In addition, we first evaluated the expression of ACE2 in various sites of the oral cavity with noninvasive, convenient liquid-based cytology. The liquid-based cytology evaluation of oral tissue may provide a novel preventive medical avenue against COVID-19.

Comparison of the Bone Regenerative Capacity of Three-Dimensional Uncalcined and Unsintered Hydroxyapatite/Poly-d/l-Lactide and Beta-Tricalcium Phosphate Used as Bone Graft Substitutes.

This study compared the in vivo applicability of three-dimensional uncalcined and unsintered hydroxyapatite/poly-d/l-lactide (3D-HA/PDLLA) with beta-tricalcium phosphate (ß-TCP). 3D-HA/PDLLA is a newly developed bioactive, osteoconductive, bioresorbable bone regenerative composite. We performed critical-defect surgery on the mandible body of rats; the defects were filled with one of two bone graft substitutes. After a 4-week follow-up period, the mandibular specimens were examined using hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC) staining and micro-computed tomography (micro-CT). The H&E staining showed an increase in newly formed bone in both groups from week 1 to 4. The difference in the Runx2 IHC optical density (OD) scores of 3D-HA/PDLLA and ß-TCP was not statistically significant (p > 0.05); however, the osteocalcin IHC OD scores of the groups differed significantly (p < 0.05). Micro-CT demonstrated a similar trabecular thickness, trabecular spacing, and bone volume per total volume in the two groups (p > 0.05), indicating that bone formation in the two groups was nearly the same from a macro-perspective of bone regeneration. These results demonstrated that a different bone regeneration pattern and earlier osteoblast differentiation occurred in 3D-HA/PDLLA compared with ß-TCP. In conclusion, our study demonstrates that 3D-HA/PDLLA is feasible for clinical application as a new bioactive, osteoconductive/bioresorbable bone graft substitute for maxillofacial surgery.

Bone Regeneration Potential of Uncalcined and Unsintered Hydroxyapatite/Poly l-lactide Bioactive/Osteoconductive Sheet Used for Maxillofacial Reconstructive Surgery: An In Vivo Study.

Uncalcined and unsintered hydroxyapatite/poly l-lactide (u-HA/PLLA) material has osteoconductive characteristics and is available for use as a maxillofacial osteosynthetic reconstruction device. However, its bone regeneration ability in the maxillofacial region has not been fully investigated. This study is the first to assess the bone regenerative potential of osteoconductive u-HA/PLLA material when it is used for repairing maxillofacial bone defects. A total of 21 Sprague-Dawley male rats were divided into three groups-the u-HA/PLLA, PLLA, or sham control groups. A critical size defect of 4 mm was created in the mandible of each rat. Then, the defect was covered with either a u-HA/PLLA or PLLA sheet on the buccal side. The rats in each group were sacrificed at 2, 4, or 8 weeks. The rats' mandibles were sampled for histological analysis with hematoxylin and eosin staining, histomorphometry, and immunohistochemistry with Runx2 and osteocalcin (OCN) antibody. The amount of newly formed bone in the u-HA/PLLA group was significantly higher than that of the PLLA group. The expression of Runx2 and OCN in the u-HA/PLLA group was also significantly higher. These results demonstrate that the u-HA/PLLA material has excellent bone regenerative ability and confirm its applicability as a reconstructive device in maxillofacial surgery.

Efficacy of Bacterial Cellulose as a Carrier of BMP-2 for Bone Regeneration in a Rabbit Frontal Sinus Model.

If the alveolar bone height of patients requiring dental implants in the maxillary molar region is inadequate, it is difficult to achieve satisfactory outcomes using existing bone graft materials. We previously reported the possible utility of bacterial cellulose (BC) as a new dental treatment material. BC has a high absorptive capacity, good mechanical strength, and good volume retention. BC loaded with bone morphogenetic protein-2 (BMP-2) might allow effective alveolar bone augmentation. We created critical frontal bone defect models in 12 male Japanese white rabbits and divided them into four groups: sham; BC (BC grafting only); BMP-2 (treated with BMP-2 solution only); and BC+BMP-2 (grafted with BC loaded with BMP-2). Newly formed bone volume was calculated via hematoxylin-eosin staining evaluation. The proliferating cell nuclear antigen and osteocalcin levels were determined by the immunohistochemical staining analysis. All measured indices of the BC+BMP-2 group were significantly superior to those of the other groups (all p < 0.05). BC maintained the graft space and released BMP-2 in a sustained manner, promoting optimal bone formation. The BC+BMP-2 combination enhanced bone regeneration and shows promise as a useful means of clinical pre-dental implant bone augmentation in the maxillary sinus.

Application of a Bioactive/Bioresorbable Three-Dimensional Porous Uncalcined and Unsintered Hydroxyapatite/Poly-D/L-lactide Composite with Human Mesenchymal Stem Cells for Bone Regeneration in Maxillofacial Surgery: A Pilot Animal Study.

A novel three-dimensional (3D) porous uncalcined and unsintered hydroxyapatite/poly-d/l-lactide (3D-HA/PDLLA) composite demonstrated superior biocompatibility, osteoconductivity, biodegradability, and plasticity, thereby enabling complex maxillofacial defect reconstruction. Mesenchymal stem cells (MSCs)-a type of adult stem cell-have a multipotent ability to differentiate into chondrocytes, adipocytes, and osteocytes. In a previous study, we found that CD90 (Thy-1, cluster of differentiation 90) and CD271 (low-affinity nerve growth factor receptor) double-positive cell populations from human bone marrow had high proliferative ability and differentiation capacity in vitro. In the present study, we investigated the utility of bone regeneration therapy using implantation of 3D-HA/PDLLA loaded with human MSCs (hMSCs) in mandibular critical defect rats. Microcomputed tomography (Micro-CT) indicated that implantation of a 3D-HA/PDLLA-hMSC composite scaffold improved the ability to achieve bone regeneration compared with 3D-HA/PDLLA alone. Compared to the sufficient blood supply in the mandibular defection superior side, a lack of blood supply in the inferior side caused delayed healing. The use of Villanueva Goldner staining (VG staining) revealed the gradual progression of the nucleated cells and new bone from the scaffold border into the central pores, indicating that 3D-HA/PDLLA loaded with hMSCs had good osteoconductivity and an adequate blood supply. These results further demonstrated that the 3D-HA/PDLLA-hMSC composite scaffold was an effective bone regenerative method for maxillofacial boney defect reconstruction.

Feasibility of a Three-Dimensional Porous Uncalcined and Unsintered Hydroxyapatite/poly-d/l-lactide Composite as a Regenerative Biomaterial in Maxillofacial Surgery.

This study evaluated the feasibility of a novel three-dimensional (3D) porous composite of uncalcined and unsintered hydroxyapatite (u-HA) and poly-d/l-lactide (PDLLA) (3D-HA/PDLLA) for the bony regenerative biomaterial in maxillofacial surgery, focusing on cellular activities and osteoconductivity properties in vitro and in vivo. In the in vitro study, we assessed the proliferation and ingrowth of preosteoblastic cells (MC3T3-E1 cells) in 3D-HA/PDLLA biomaterials using 3D cell culture, and the results indicated enhanced bioactive proliferation. After osteogenic differentiation of those cells on 3D-HA/PDLLA, the osteogenesis marker genes runt-related transcription factor-2 (Runx2), and Sp7 (Osterix) were upregulated. For the in vivo study, we evaluated the utility of 3D-HA/PDLLA biomaterials compared to the conventional bone substitute of beta-tricalcium phosphate (ß-TCP) in rats with critical mandibular bony defects. The implantation of 3D-HA/PDLLA biomaterials resulted in enhanced bone regeneration, by inducing high osteoconductivity as well as higher ß-TCP levels. Our study thus showed that the novel composite, 3D-HA/PDLLA, is an excellent bioactive/bioresorbable biomaterial for use as a cellular scaffold, both in vitro and in vivo, and has utility in bone regenerative therapy, such as for patients with irregular maxillofacial bone defects.

Expression of aquaporin 3 and 5 as a potential marker for distinguishing dry mouth from Sjögren's syndrome.

A study was performed to investigate whether expression of aquaporin (AQP) 3 and 5 has potential as a marker for distinguishing dry mouth from Sjögren's syndrome. Twenty-five patients underwent labial minor salivary gland biopsy (dry mouth, n = 9; Sjögren's syndrome, n = 16; control, n = 8). All patients were interviewed about their medical history and subjective oral symptoms, and intraoral examinations were conducted. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry were used to examine the expression and localization of AQP3 and 5. Significant differences in oral dryness, dry eye, medical history, and Saxon test results were revealed among the groups. However, there were no significant inter-group differences in expression of mRNA for AQP3 and 5. Immunohistochemical staining for AQP3 was localized mainly in the basolateral and part of the ductal cell membrane, and was barely evident in the apical membrane of acinar cells. AQP5 was localized to the basolateral and apical membrane and cytoplasm, but not the ductal cell membrane. Staining intensity for AQP3 in the apical membrane was significantly stronger in Sjögren's syndrome, and that for AQP5 was significantly weaker in dry mouth. Taken together, the present data suggest that expression of AQP3 and 5 may be a marker for distinguishing between patients with dry mouth and those with Sjögren's syndrome.

Applicability of preoperative nuclear morphometry to evaluating risk for cervical lymph node metastasis in oral squamous cell carcinoma.

BACKGROUND: We previously reported the utility of preoperative nuclear morphometry for evaluating risk for cervical lymph node metastases in tongue squamous cell carcinoma. The risk for lymph node metastasis in oral squamous cell carcinoma, however, is known to differ depending on the anatomical site of the primary tumor, such as the tongue, gingiva, mouth floor, and buccal mucosa. In this study, we evaluated the applicability of this morphometric technique to evaluating the risk for cervical lymph node metastasis in oral squamous cell carcinoma. METHODS: A digital image system was used to measure the mean nuclear area, mean nuclear perimeter, nuclear circular rate, ratio of nuclear length to width (aspect ratio), and nuclear area coefficient of variation (NACV). Relationships between these parameters and nodal status were evaluated by t-test and logistic regression analysis. RESULTS: Eighty-eight cases of squamous cell carcinoma (52 of the tongue, 25 of the gingiva, 4 of the buccal mucosa, and 7 of the mouth floor) were included: 46 with positive node classification and 42 with negative node classification. Nuclear area and perimeter were significantly larger in node-positive cases than in node-negative cases; however, there were no significant differences in circular rate, aspect ratio, or NACV. We derived two risk models based on the results of multivariate analysis: Model 1, which identified age and mean nuclear area and Model 2, which identified age and mean nuclear perimeter. It should be noted that primary tumor site was not associated the pN-positive status. There were no significant differences in pathological nodal status by aspect ratio, NACV, or primary tumor site. CONCLUSION: Our method of preoperative nuclear morphometry may contribute valuable information to evaluations of the risk for lymph node metastasis in oral squamous cell carcinoma.

Applicability of bacterial cellulose as an alternative to paper points in endodontic treatment.

Dental root canal treatment is required when dental caries progress to infection of the dental pulp. A major goal of this treatment is to provide complete decontamination of the dental root canal system. However, the morphology of dental root canal systems is complex, and many human dental roots have inaccessible areas. In addition, dental reinfection is fairly common. In conventional treatment, a cotton pellet and paper point made from plant cellulose is used to dry and sterilize the dental root canal. Such sterilization requires a treatment material with high absorbency to remove any residue, the ability to improve the efficacy of intracanal medication and high biocompatibility. Bacterial cellulose (BC) is produced by certain strains of bacteria. In this study, we developed BC in a pointed form and evaluated its applicability as a novel material for dental canal treatment with regard to solution absorption, expansion, tensile strength, drug release and biocompatibility. We found that BC has excellent material and biological characteristics compared with conventional materials, such as paper points (plant cellulose). BC showed noticeably higher absorption and expansion than paper points, and maintained a high tensile strength even when wet. The cumulative release of a model drug was significantly greater from BC than from paper points, and BC showed greater compatibility than paper points. Taken together, BC has great potential for use in dental root canal treatment.

Stimulatory effect of hydrothermally synthesized biodegradable hydroxyapatite granules on osteogenesis and direct association with osteoclasts.

Calcium-deficient hydroxyapatite (HA) granules with a unique spherical shape were prepared using an applied hydrothermal method. Spherical stoichiometric HA granules were also prepared by normal sintering and both granules were used for implantation into rat tibiae to compare the biological responses to each implant. Twelve and 24 weeks after implantation, the volume of calcium-deficient HA granules was significantly less than that of stoichiometric HA granules, and the biodegradability of calcium-deficient HA granules was confirmed. The larger number of osteoclasts, larger osteoblast surface and larger bone volume in the implanted area of calcium-deficient HA than those of stoichiometric HA suggested that osteoclastic resorption of calcium-deficient HA affected osteogenesis in that area. To analyze the direct contribution of osteoclasts to osteogenesis, C2C12 multipotent myoblastic cells, which have the potential to differentiate into osteoblasts in the presence of bone morphogenetic protein 2, were cultured with supernatants of osteoclasts cultured on calcium-deficient HA, stoichiometric HA, beta-tricalcium phosphate disks or plastic dishes, or bone marrow macrophages cultured on plastic dishes. Supernatants of osteoclasts but not bone marrow macrophages stimulated the expression of Runx2 and osteocalcin in C2C12 cells in concert with bone morphogenetic protein 2. The expression of alkaline phosphatase was stimulated with supernatants of osteoclasts cultured on ceramic disks. These results suggested that osteoclasts produced certain soluble factors which stimulated osteoblastic differentiation and they were thought to be associated with the induction of a larger osteoblast surface and bone volume in the animals implanted with calcium-deficient HA granules.