Recently, a number of recent reports have reported cases of bone marrow defect (BMD) in the mandible. Among the diseases seen by BMD in radiographs, focal osteoporotic bone marrow defect(FOBMD) is asymptomatic, which is discovered incidentally and localized radiolucency. Because it varies in size, shape, trabeculae and border definition, it needs to biopsy to differential diagnose other intraosseous lesions that show radiological bone marrow defects. This cases report discusses the pre-operation considerations in patients planning to implant the mandible and suspected to have FOBMD in radiographs. The following 4 cases in Dental Hospital of Wonkwang University were taken in panoramic and Cone beam computed tomography(CBCT). In all cases, there were radiolucent lesion diagnosed with FOBMD under radiologic differential diagnosis. In three of cases the implant were placed without treatment plan change and one case changed the treatment plan with removable partial denture. BMD is anatomical state that can affect primary stability of implant fixture. During implant placement, it can lead to unexpected results that fixture is fallen into BMD and the nerve may be damaged after implant fixture removal to cause hyperesthesia. Preoperative diagnosis of these lesions by differential diagnosis with panoramic and CBCT can prevent the complications by changing the treatment plan or paying attention to the manipulation during surgery.

Exosomes are Nano-sized lipid vesicles secreted from mammalian cells containing diverse cellular materials such as proteins, lipids, and nucleotides. Multiple lines of evidence indicate that in saliva, exosomes and their contents such as microRNAs (miRNAs) mediate numerous cellular responses upon delivery to recipient cells. The objective of this study was to characterize the different expression profile of exosomal miRNAs in saliva samples, periodically isolated from a single periodontitis patient. Unstimulated saliva was collected from a single patient over time periods for managing periodontitis. MicroRNAs extracted from each phase were investigated for the expression of exosomal miRNAs. Salivary exosomal miRNAs were analyzed using Affymetrix miRNA arrays and prediction of target genes and pathways for its different expression performed using DIANA-mirPath, a web-based, computational tool. Following the delivery of miRNA mimics (hsa-miR-4487, -4532, and -7108-5p) into human gingival fibroblasts, the expression of pro-inflammatory cytokines and activation of the MAPK pathway were evaluated through RT-PCR and western blotting. In each phase, 13 and 43 miRNAs were found to be differently expressed (|FC| ≥ 2). Among these, hsa-miR-4487 (|FC|=9.292005) and hasmiR- 4532 (|FC|=18.322697) were highly up-regulated in the clinically severe phase, whereas hsa-miR-7108-5p (|FC|= 12.20601) was strongly up-regulated in the clinically mild phase. In addition, the overexpression of miRNA mimics in human gingival fibroblasts resulted in a significant induction of IL-6 mRNA expression and p38 phosphorylation. The findings of this study established alterations in salivary exosomal miRNAs which are dependent on the severity of periodontitis and may act as potential candidates for the treatment of oral inflammatory diseases.

Retinoic acid plays an important role in the regulation of cell growth and differentiation. In our present study, we evaluated the effects of all-trans retinoic acid (RA) on cell proliferation and on the cell cycle regulation of human gingival fibroblasts (HGFs). Cell proliferation was assessed using the MTT assay. Cell cycle analysis was performed by flow cytometry, and cell cycle regulatory proteins were determined by western blot. Cell proliferation was increased in the presence of a 0.1 nM to 1μM RA dose range, and maximal growth stimulation was observed in cells exposed to 1 nM of RA. Exposure of HGFs to 1 nM of RA resulted in an augmented cell cycle progression. To elucidate the molecular mechanisms underlying cell cycle regulation by RA, we measured the intracellular levels of major cell cycle regulatory proteins. The levels of cyclin E and cyclin-dependent kinase (CDK) 2 were found to be increased in HGFs following 1 nM of RA treatment. However, the levels of cyclin D, CDK 4, and CDK 6 were unchanged under these conditions. Also after exposure to 1 nM of RA, the protein levels of p21 WAF1/CIP1 and p16 INK4A were decreased in HGFs compared with the control group, but the levels of p53 and pRb were similar between treated and untreated cells. These results suggest that RA increases cell proliferation and cell cycle progression in HGFs via increased cellular levels of cyclin E and CDK 2, and decreased cellular levels of p21 WAF1/CIP1 and p16 INK4A.