The coronavirus disease 2019 (COVID-19) has seen a violent and fast spread worldwide. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a predominantly respiratory transmission through droplets and aerosol with serious implications for dental settings. This article is based on recent research, guidelines issued by relevant authorities, as well as on the authors’ experience acquired through their involvement in setting up an emergency dental care hub in Cluj-Napoca, Romania, during the COVID-19 lockdown. The present article aims to provide a brief description of COVID-19 implications in dental office and to recommend preventive protocols for dental practitioners to ensure a safe and healthful workplace. The recommendations for infection control presented in this article address the specific risks of exposure to SARS-CoV-2. The article provides a special customized guideline covering patient triage and entrance into the dental practice, personnel protection, dental treatment, and after-treatment management. The implementation of strict preventive measures has been found to be efficient in the prevention of SARS-CoV-2 contamination because no infections have been reported among our staff or patients. COVID-19 is a major emergency worldwide marked by a rapid evolution and warranting a need for further assessment of the implications of COVID-19 outbreak in dental practice.

Early Copper Age pottery sherds discovered in a cave within the crystalline dolomites of the Southern Carpathians (Romania) were investigated by polarized light optical microscopy (OM), X-ray powder diffraction (XRPD) and electron microprobe analysis (EMPA) to obtain information on the pottery production in the Copper Age in the territory of present-day Romania. Microscopically, the clayey matrix of the ceramic body is highly birefringent or consists of low-birefringent and isotropic parts mixed together, containing fragments of quartz, muscovite, alkali feldspar, plagioclase, biotite, chlorite, heavy minerals and metamorphic and magmatic rocks, as well as an opaque material. The EMPA data revealed an Fe-rich illite-like matrix and helped to identify the mineral nature of the inclusions. Local pottery production in bonfires or surface clamps is envisaged. Miocene illitic clays may have been used as raw materials, mixed with a small amount of sandy temper. The thermal changes revealed by OM, the modification of the XRPD peaks and the EMPA data suggest firing temperatures of between 800 and 850°C.

Resin composite materials that are used to restore tooth cervical lesions associated with gingival recessions can hamper healing after root coverage surgeries. This study evaluates the in vitro cytotoxic effect of five resin composites (two commercial and three experimental) on oral mesenchymal stem cells (MSCs) and the persistence of stemness properties in high passage MSCs. Sorption and solubility tests were made for all materials. MSCs were isolated from re-entry palatal and periodontal granulation tissues and were characterized and cultured on composite discs. Cytotoxicity of the materials was evaluated by the Alamar Blue viability test, by Paul Karl Horan (PKH) labeling, and by immunocytochemical staining for actin. Water and saliva sorption and solubility data revealed that two of the experimental materials behaved comparable with the marketed resin composites. The Alamar Blue viability test shows that both cell lines grew well on composite discs that seemed to induce no apparent toxic effects. No signs of disruption of cytoskeleton organization was seen. Experimental resin composites can be recommended for further investigation for obtaining approval for use. The standard minimal criteria were fulfilled for high passage MSCs. Palatal tissue regains its regenerative properties in terms of MSC presence in the re-entry area after 6 months of healing.

The aim of the present study was to isolate human mesenchymal stem cells (MSCs) from palatal connective and periodontal granulation tissues and to comparatively evaluate their properties. MSCs were isolated using the explant culture method. Adherence to plastic, specific antigen makeup, multipotent differentiation potential, functionality, and ultrastructural characteristics were investigated. The frequency of colony-forming unit fibroblasts for palatal-derived mesenchymal stem cells (pMSCs) was significantly higher than that of granulation tissue-derived mesenchymal stem cells (gtMSCs). A significantly higher population doubling time and lower migration potential were recorded for gtMSCs than for pMSCs. Both cell lines were positive for CD105, CD73, CD90, CD44, and CD49f, and negative for CD34, CD45, and HLA-DR, but the level of expression was different. MSCs from both sources were relatively uniform in their ultrastructure. Generally, both cell lines possessed a large, irregular-shaped euchromatic nucleus, and cytoplasm rich in mitochondria, lysosomes, and endoplasmic reticulum. The periphery of the plasma membrane displayed many small filopodia. MSCs from both cell lines were successfully differentiated into osteogenic, adiopogenic, and chondrogenic lineages. Both healthy and diseased tissues may be considered as valuable sources of MSCs for regenerative medicine owing to the high acceptance and fewer complications during harvesting.

The aim of the present research was to trace CD34+ stromal fibroblastic cells (CD34+ SFCs) in the palatal connective tissue harvested for muco-gingival surgical procedures and in granulation tissues from periodontal pockets using immunohistochemical and transmission electron microscopy. Immunohistochemical analysis targeted the presence of three antigens: CD31, α-smooth muscle actin (α-SMA), and CD34. In the palate, CD31 staining revealed a colored inner ring of the vessels representing the endothelium, α-SMA+ was located in the medial layer of the vasculature, and CD34 was intensely expressed by endothelial cells and artery adventitial cells (considered to be CD34+ SFCs). Granulation tissue showed the same pattern for CD31+ and α-SMA, but a different staining pattern for CD34. Ultrastructural examination of the palatal tissue highlighted perivascular cells with fibroblast-like characteristics and pericytes in close spatial relationship to endothelial cells. The ultrastructural evaluation of granulation tissue sections confirmed the presence of neovasculature and the inflammatory nature of this tissue. The present study traced the presence of CD34+ SFCs and of pericytes in the palatal connective tissue thus highlighting once more its intrinsic regenerative capabilities. The clinical and systemic factors triggering mobilization and influencing the fate of local CD34+SCFs and other progenitors are issues to be further investigated.

The aim of this study was to analyze whether the mesenchymal stromal cells (MSCs) isolated from palatal tissue grafts harvested in order to cover gingival recessions have the basic characteristics of stem cells. The palatal tissue cells were processed using a special culture medium that stimulated the development of only undifferentiated cellular lines. Cells at passage 4 were evaluated by flow cytometry to examine the expression of specific surface markers and were tested for multilineage differentiation capacity. These cells collected at passage 4 were also investigated for the capacity to cluster into embryoid body aggregates. Palatal MSCs displayed positive staining for the mesenchymal markers CD29, CD73, CD105, CD 49e, and CD44, but did not express hematopoietic markers CD34/45. The palatal MSCs successfully differentiated into osteogenic, adipogenic, and chondrogenic lineages. When seeded in special conditions, palatal MSCs propagated into unattached spheres resembling embryoid body aggregates consisting both of differentiated and undifferentiated cells as revealed at the ultrastructural evaluation. It is concluded that the isolated palatal MSCs fulfilled the basic criteria defining the stem cells. This new source of stem cells characterized here for the first time opens new perspectives on possible applications in basic research and in regenerative medicine.