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Stem cells are present in many tissues, such as dental pulp. Stem cells can be easily isolated from dental pulp because third molars are often removed from patients. Stem cells could be separated from the tissue derived heterogeneous cell population. There are two main methods to separate a cell type from the other ones: the fluorescence activated cell sorting (FACS) and the magnetic activated cell sorting (MACS). The aim of this study was to compare these methods' effect on cell surviving and population growth after sorting on dental pulp cells. The anti-STRO-1 antibody was used as primary antibody to specifically label stem cells. Two secondary antibodies were used: magnetic or fluorescent labelled. We sorted the cells by MACS or by FACS or by combination of both (MACS-FACS). Our results show that the effectivity of MACS and FACS sorting are comparable while of MACS-FACS was significantly higher (MACS 79.53 ± 5.78%, FACS 88.27 ± 3.70%, MACS-FACS 98.43 ± 0.67%). The cell surviving and the post-sorting population growth, on the contrary, are very different. The cell population is growing on first week after MACS but after FACS did not. Moreover, after MACS-FACS, on first week the cell number of population decreased. Taken together, our results suggest to use MACS instead of FACS, at least in case of sorting dental pulp stem cells with anti-STRO-1 antibody.

Salivary gland hypofunction, which may occur in head and neck cancers following therapeutic irradiation or in Sjogren's syndrome, drastically impair the patient's quality of life. Conventional treatments do not provide a satisfactory solution to the problem, therefore it is becoming increasingly urgent to develop completely new management approaches in particular, the challenge of restoring the function of acini. Many biologically based interventions studied, thus "reprogramming" with gene therapy of survivor ducts or regeneration potential of progenitor cells in the salivary gland. Our research group has been working on several models, which have shown that by using appropriate media containing extracellular proteins (e.g. BME, basal membrane extract) can be achieved acinar differentiation. A significant proportion of in vitro models of salivary gland are submandibular of origin, which however is different from the development and function of parotid. Our research group aimed to model the potential treatment options for salivary gland hypofunction, the carrier or bioactive molecules directed differentiation, as well as the potential of gene therapy on rat parotid-derived cell line (Par-C10). In our experiments, we have studied the morphological changes of Par-C10 cells cultured on permeable polyester membrane, or in three-dimensional cultures, using varying concentrations of BME. In addition, we have tested the use of recombinant adenovirus vectors that could modify Par-C10 cells and make them useful in gene therapy models. Our data suggest that Par-C10 cell line is suitable for modelling parotid gland tissue organization and may also serve as a useful gene therapy model system.

Evidence has been accumulating for the presence of stem cells in dental tissues. The authors' studies aimed to produce primary culture from human dental pulp. Furthermore, they wanted to identify clonogenic cells with progenitor properties in these cultures, and to characterize their proliferative capacity. The dental pulp was isolated from surgically removed wisdom teeth. The extracellular matrix was enzymatically degraded to obtain isolated cells for culturing. Identification of STRO-1 mesenchymal stem cell marker was achieved by immunocytochemistry. Osteogenic differentiation was detected by the application of Alizarin Red. The proliferative activity of the cell cultures in response to serum, EGF and BMP2 was estimated by MTT assay. The authors' most important finding is the successful establishment of stable primary cell culture from human dental pulp tissue. The cultures can be passaged multiple times and they contain clonogenic, STRO-1 immunopositive cells. Their mineralization capacity was shown by mineralized deposits as a result of induction by suitable medium. The presence of serum increased, while both EGF and BMP2 concentration-dependently decreased the cell proliferation in the cultures. The authors' model provides the foundation for studies of the proliferation and differentiation of dental pulp cells at molecular level, and opens a new direction towards the biological regeneration of dental tissues.

Recent studies have revealed the presence of postnatal stem cells in tissues of dental origin. Our objective was to establish a standardized in vitro model system to investigate periodontal regenerative procedures for potential clinical application. We aimed to prepare primary cell cultures from human periodontal ligament and to identify clonogenic progenitor cells. After scraping PDL tissue from extracted wisdom teeth, the extracellular matrix was enzymatically degraded to obtain isolated cells for culturing. The effect of FCS and Emdogain on cell viability of the cultures was estimated by MTT-assay. Cell populations expressing STRO-1 mesenchymal, c-kit embryonic and CD34 hematopoietic stem cell markers were identified by FACS-analysis. We successfully established primary cell cultures from the human PDL. The proliferation rate of the cultures was enhanced by the supplementation of the culture medium by serum or Emdogain. The PDL cultures contained cells capable of colony-formation, as well as cells with STRO-1, c-kit and CD-34 expression. The primary cultures were maintained through multiple passages. These findings present a novel opportunity to further investigate the differentiation and proliferation of PDL derived cells potentially capable of periodontal regeneration.

An increasing number of evidence supports the assumption that genetic factors have crucial role in the development of periodontitis and hypodontia. The strategic purpose of the authors is to identify the genetic background of these disorders and to map the gene polymorphisms involved in their development. As a first step of an experimental series, we aimed to set and optimize multiple individual gene polymorphism identification methods by the combination of polymerase chain reaction and restriction fragment length polymorphism analysis methods. We have successfully optimized eight single nucleotide polymorphism procedures that are potentially involved in periodontitis (IL-1 alpha -889, IL-1 beta -511, IL-1 beta +3954, IL-6 -174, IL-10 -1082, TLR-4 -299, TLR-4 -399, TNF-alpha -308), and another two that might be related to the appearance of hypodontia (PAX9 -1032, PAX9 -912). Besides the dominant allele, we also observed the presence of the rare allele in each polymorphism although at present we have a small sample number. These preliminary studies provide evidence for the feasibility of further investigations with large sample numbers comparing control and patient groups. These studies may lead to the development of new diagnostic strategies and provide novel tools for the early recognition of genetic predisposition and the primary control of the diseases. Furthermore, they project future therapeutic avenues for gene therapy in the cure and prevention of oral disorders.

The prevalence of gastro-esophageal reflux disease (GERD), as well as that of dental erosion (DE), increases steeply in the 21th century societies of Europe and North America. GERD is a multicausal disease, with genetic, anatomical and neurological insufficiencies in the background, complemented with behavioral factors. In GERD, as reflux occurs more often and lasts longer than physiologically, the result is esophagitis and supraesophageal manifestations. The acid, which might even reach the mouth, interacts with the material of the teeth and demineralization, a form of dental erosion takes place. Clinical studies have proved, that in patients suffering from GERD dental erosion takes place significantly more often than in patients who do not. It was also confirmed that in patients with idiopathic dental erosion GERD is significantly more frequent than in the "uneroded" population. These data suggest that in case of extended dental erosion the dentist should think of a - possibly not yet diagnosed - gastroenterological disease.

The experience of the past decade proves that tooth wear occurs in an increasing number of cases in general dental practice. Tooth wear may have physical (abrasion and attrition) and/or chemical (erosion) origin. The primary physical causes are inadequate dental hygienic activities, bad oral habits or occupational harm. As for dental erosion, it is accelerated by the highly erosive foods and drinks produced and sold in the past decades, and the number of cases is also boosted by the fact that bulimia, anorexia nervosa and gastro-oesophageal reflux disease prevalence have become more common. The most important defensive factor against tooth wear is saliva, which protects teeth from the effect of acids. Tertiary dentin formation plays an important role in the protection of the pulp. Ideally, destructive and protective factors are in balance. Both an increase in the destructive forces, and the insufficiency of defense factors result in the disturbance of the equilibrium. This results in tooth-wear, which means an irreversible loss of dental hard tissue. The rehabilitation of the lost tooth material is often very difficult, irrespectively of whether it is needed because of functional or esthetic causes. For that reason, the dentist should carry out primary and secondary dental care and prevention more often, i.e. dental recall is indispensable every 4-6 months.