Cryopreservation of human dental follicle tissue for use as a resource of autologous mesenchymal stem cells.

The main purpose of this study was to develop a cryopreservation method for human dental follicle tissue to maintain autologous stem cells as a resource. A modified cryoprotectant, consisting of 0.05 m glucose, 0.05 m sucrose and 1.5 m ethylene glycol in phosphate-buffered saline (PBS) was employed, with a slow-ramp freezing rate. We observed > 70% of cell survival rate after 3 months of tissue storage. Isolated and cultured human dental stem cells (hDSCs) from cryopreserved dental follicles expressed mesenchymal stem cell markers at a level similar to that of hDSCs from fresh tissue. They also successfully differentiated in vitro into the mesenchymal lineage, osteocytes, adipocytes and chondrocytes under specific inductions. Using immunohistochemistry, the early transcription factors OCT4, NANOG and SOX2 were moderately or weakly detected in the nucleus of both fresh and cryopreserved dental follicles. In addition, p63, CCND1, BCL2 and BAX protein expression levels were the same in both fresh and cryopreserved tissues. However, the positive-cell ratio and intensity of p53 protein was higher in cryopreserved tissues than in fresh tissues, indicating direct damage of the freeze-thawing process. Real-time PCR analysis of hDSCs at passage 2 from both fresh and cryopreserved dental follicles showed similar levels of mRNA for apoptosis- and transcription-related genes. Based on these results, a newly developed cryoprotectant, along with a slow ramp rate freezing procedure allows for long-term dental tissue preservation for later use as an autologous stem cell resource in regenerative cell therapy. Copyright © 2014 John Wiley & Sons, Ltd.

Co-development of pyogenic granuloma and capillary hemangioma on the alveolar ridge associated with a dental implant: a case report.

INTRODUCTION: The development of various benign oral mucosal lesions associated with dental implants, such as pyogenic granuloma or peripheral giant cell granuloma, has been rarely reported. However, the occurrence of vascular diseases, such as hemangioma, related to dental implants has not been explored in the literature. In this study, we report a case of co-development of pyogenic granuloma and capillary hemangioma on the alveolar ridge associated with a dental implant in a patient undergoing antithrombotic therapy. To the best of our knowledge, this is first case of hemangioma formation associated with a dental implant. CASE PRESENTATION: A 68-year-old Korean man was referred for intermittent bleeding and a dome-shaped overgrowing mass on his upper alveolar ridge. He underwent dental implantation 5 years ago, and was started on warfarin for cerebral infarction a year ago. He had experienced gum bleeding and gingival mass formation 6 months after warfarinization; then, his implant fixture was removed. However, his gingival mass has been gradually increasing. The gingival mass was surgically excised, and revealed the coexistence of pyogenic granuloma and capillary hemangioma in histological analysis of the specimen. The lesion has showed no recurrence for more than a year. CONCLUSIONS: Regarding immunostaining features, the endothelial cell markers, CD34 and CD31, and the mesenchymal cell marker, vimentin, were strongly detected, but cell proliferation marker, Ki-67, was negatively expressed in the endothelial cells of the hemangioma portion. However, in the pyogenic granuloma portion, CD34 was almost negatively detected, whereas vimentin and Ki-67 were highly detected in the fibroblast-like tumor cells. According to these heterogeneous characteristics of the lesion, the patient was diagnosed with coexistence of pyogenic granuloma and capillary hemangioma associated with the dental implant on the attached gingiva. We recommend that patients with dental implants who have chronic peri-implantitis under antithrombotic therapy should be closely followed to ensure early detection of oral mucosal abnormalities.

Expansile keratocystic odontogenic tumor in the maxilla: immunohistochemical studies and review of literature.

Keratocystic odontogenic tumors (KCOT) - previously termed odontogenic keratocysts (OKC) - are characterized by aggressive behavior and a high rate of recurrence. Histopathologically, the basal layer of KCOT shows a higher cell proliferation rate and increased expression of anti-apoptosis genes. Clinically, KCOT is frequently involved in the mandibular posterior region but is not common in the posterior maxilla. However, it should be noted that due to its expansive characteristics, KCOT involved near the maxillary sinus could easily expand to an enormous size and occupy the entire maxilla. To achieve total excision of these expanded cystic tumors in the maxilla, a more aggressive approach would be needed. In this report, we describe two cases of expansile KCOT involving the entire unilateral maxilla and maxillary sinus; they were completely excised using the Weber-Ferguson approach, showing no evidence of recurrence during the follow-up period of more than two years. In immunohistochemical analyses of the tumor specimens, p53 and p63 showed strong expression, and B-cell lymphoma 2 (BCL2) and MKI67 (Ki-67) showed moderate or weak expression, however, detection of BCL2-associated X protein (BAX) was almost negative. These data indicate that expansile KCOT possesses increased anti-apoptotic activity and cell proliferation rate but decreased apoptosis. These properties of KCOT may contribute to tumor enlargement, aggressive behavior, and high recurrence rate.