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Keloid disease is a fibroproliferative dermal tumor with an unknown etiology that occurs after a skin injury in genetically susceptible individuals. Increased familial aggregation, a higher prevalence in certain races, parallelism in identical twins, and alteration in gene expression all favor a remarkable genetic contribution to keloid pathology. It seems that the environment triggers the disease in genetically susceptible individuals. Several genes have been implicated in the etiology of keloid disease, but no single gene mutation has thus far been found to be responsible. Therefore, a combination of methods such as association, gene-gene interaction, epigenetics, linkage, gene expression, and protein analysis should be applied to determine keloid etiology.

The aim of this article is to provide a brief insight regarding the recent studies and their recommendations related to the modifications to glass ionomer cement (GIC) powder in order to improve their properties. An electronic search of publications was made from the year 2000 to 2018. The databases included in the current study were EBSCOhost, PubMed, and ScienceDirect. The inclusion criteria for the current study include publication with abstract or full-text articles, original research, reviews or systematic reviews, in vitro, and in vivo studies that were written in English language. Among these only articles published in peer-reviewed journals were included. Articles published in other languages, with no available abstract and related to other nondentistry fields, were excluded. A detailed review of the recent materials used as a filler phase in GIC powder has revealed that not all modifications produce beneficial results. Recent work has demonstrated that modification of GIC powder with nano-particles has many beneficial effects on the properties of the material. This is due to the increase in surface area and surface energy, along with better particle distribution of the nano-particle. Therefore, more focus should be given on nano-particle having greater chemical affinity for GIC matrix as well as the tooth structure that will enhance the physicochemical properties of GIC.

Stem cells derived from human exfoliated deciduous teeth (SHED) represent a promising cell source for bone tissue regeneration. This study evaluated the effects of interleukin-17A (IL-17A) on the osteogenic differentiation of SHED. SHED were cultured in complete alpha minimum essential medium supplemented with osteoinducing reagents and treated with recombinant IL-17A. The cells were quantitatively analysed for proliferative activity by MTS assay, cell markers expression, and apoptotic activity by flow cytometry. For osteogenic differentiation, alkaline phosphatase (ALP) activity was quantified; mineralization assays were carried out using von Kossa and Alizarin red, and expression of osteogenic markers were analysed by real-time polymerase chain reaction and Western blot. The results showed that treatment with IL-17A increased proliferative activity in a dose-dependent manner, but reduced the expression of stem cell markers (c-Myc and Nanog) as the days progressed. IL-17A induced osteogenic differentiation in SHED as evidenced by high ALP activity, increased matrix mineralization, and upregulation of the mRNA expression of the osteogenic markers ALP, alpha 1 type 1 collagen (Col1A1), runt-related transcription factor 2 (RUNX2), osteopontin (OPN), osteocalcin (OCN), and osteoprotegerin (OPG) but downregulation of receptor activator of nuclear factor κB ligand (RANKL) as well as altering the OPG/RANKL ratio. Findings from our study indicate that IL-17A enhances proliferation and osteogenic differentiation of SHED by regulating OPG/RANKL mechanism thus suggests therapeutic potential of IL-17A in bone regeneration.

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Advancement in cell culture protocols, multidisciplinary research approach, and the need of clinical implication to reconstruct damaged or diseased tissues has led to the establishment of three-dimensional (3D) test systems for regeneration and repair. Regenerative therapies, including dental tissue engineering, have been pursued as a new prospect to repair and rebuild the diseased/lost oral tissues. Interactions between the different cell types, growth factors, and extracellular matrix components involved in angiogenesis are vital in the mechanisms of new vessel formation for tissue regeneration. In vitro pre-vascularization is one of the leading scopes in the tissue-engineering field. Vascularization strategies that are associated with co-culture systems have proved that there is communication between different cell types with mutual beneficial effects in vascularization and tissue regeneration in two-dimensional or 3D cultures. Endothelial cells with different cell populations, including osteoblasts, smooth muscle cells, and fibroblasts in a co-culture have shown their ability to advocate pre-vascularization. In this review, a co-culture perspective of human gingival fibroblasts and vascular endothelial cells is discussed with the main focus on vascularization and future perspective of this model in regeneration and repair.

White Portland cement (WPC) has generated research interests in the field of endodontics. This study compared between the properties of two formulations of white Portland cement (WPC) of different origin (Malaysia [MA] and Egypt [EG]). WPCs with and without calcium chloride dihydrate were prepared. Scanning electron microscope (SEM), energy dispersive X-ray micro-analysis, and X-ray diffraction were used for surface morphology evaluation, elemental, and phase analysis, respectively. After the preparation of optimized serial dilutions, the cytotoxicity was evaluated on human periodontal ligament fibroblasts (HPLFs) and dental pulp stem cells (DPSCs) using methyl-thiazol-diphenyltetrazolium assay after 24 and 72 h. Cell attachment properties were examined under SEM after 24 and 72 h. Results showed that the surface morphology and chemical composition of both formulations demonstrated detectable variations. The cytotoxicity evaluation showed different cellular responses of HPLFs compared to DSPCs. Both formulations favored the viability of HPLFs. However, the fast set formulations demonstrated severe cytotoxicity on DPSCs. Significant differences between EGWPC and MAWPC were identified (p < 0.05). The cell attachment properties were favorable; however, HPLFs attached and spread over the samples better than DPSCs. In conclusion, WPC of different origin may show differences in chemical and biological properties. The addition of CaCl2 ·2H2 O to WPC can affect its properties. Human cell types may react differently towards different formulations of WPCs. SCANNING 38:303-316, 2016. © 2015 Wiley Periodicals, Inc.

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