Long-term cryopreservation of dental stem cells.

Cryopreservation is a procedure of a long-term storage of cells and/or tissues at a temperature that prevents cell divisions and metabolic processes. Due to ability to self-renewal and differentiation into more specialised cells, stem cells may be helpful in repairing of other damaged organs or tissues. Cryopreservation allows the frozen genetic material to maintain its biological properties for a long time. Therefore, there is a real chance for some samples to be used in the future therapy of the pathological conditions that at present remain incurable because of the current state of knowledge. The purpose of this review is to describe the modern methods of extraction, preservation, and storage of dental stem cells at low temperatures in particular procedure of collecting and transporting tissues intended for freezing, precise characteristics of stem cells of dentary origin and methods of their isolation using Enzymatic Digestion and Spontaneous Outgrowth. In the paper are also presented technical details of the protocols of rapid rate freezing, controlled rate milling and freezing in a magnetic field (magnetic freezing) which provides precise information about procedures of thawing cells and unfavourable effect of negative temperature on the biological properties of stem cells. Dental tissues may constitute a rich source of stem cells. The inexpensive, simple and quick procedure of their extraction is minimally invasive and does not pose a threat to the donor's organism. Transferring autologous cells within the same organism does not present a potential risk of transplant rejection and thereof does not raise ethical controversies. Laboratory procedures including cell preparation, its characteristics and genetic features, basics on the process of freezing, thawing, as well as quality control essentials have been also outlined.

Oral complaints in patients with acute myeloid leukemia treated with allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Acute myeloid leukemia belongs to proliferative diseases of the hematopoietic system. It is currently the leading indication for allogeneic hematopoietic stem cell transplantation. This study was designed to determine the most common subjective oral mucosa complaints in patients with acute myeloid leukemia after allogeneic hematopoietic cell transplantation, in relation to the type of conditioning used. MATERIAL AND METHODS: Eighty patients diagnosed with acute myeloid leukemia were assigned to two groups depending on the intensity of the conditioning regimen before transplantation: myeloablative and reduced-intensity chemotherapy. The oral symptoms were evaluated based on an authorial questionnaire designed for this analysis. The following oral mucosa subjective complaints were included: pain, paraesthesia, burning mouth sensation, taste disorders, excessive salivation, halitosis, and dryness of the oral mucosa. RESULTS: The most commonly reported subjective oral complaint in the examined patients was xerostomia, which was found in 92% of patients during the second visit, followed by spontaneous pain in the mouth (55%), burning (36%), and dysgeusia (20%). It occurred significantly more frequently in patients who underwent myeloablative conditioning. Moreover, it was observed that the frequency of complaints increased considerably after the transplantation, reaching a peak intensity during the second week following the procedure. CONCLUSIONS: Oral complaints significantly decrease the patients' quality of life during the transplantation and may lead to premature termination of the treatment. As the number of transplantations in patients with acute myeloid leukemia increases, further investigations of oral complaints and symptoms induced by the disease itself and by the therapeutic approaches are required.

The effects of titanium topography and chemical composition on human osteoblast cell.

The objective of this study was to evaluate and compare titanium surfaces: machined (MA); sintered ceramic-blasted (HAS); sintered ceramic-blasted and acid-etched (HAS DE) and to determine the effects of surface topography, roughness and chemical composition on human osteoblast cell reaction. Titanium surface samples were analyzed with respect to surface chemical composition, topography, and roughness. The effects of material surface characteristics on osteoblasts was examined by analyzing osteoblast morphology, viability and differentiation. Osteoblasts cultured on these materials had attached, spread and proliferated on every sample. The viability of osteoblasts cultured on HAS and HAS DE samples increased more intensively in time comparing to MA sample. The viability of osteoblast cultured on HAS samples increased more intensively in the early phases of culture while for cells cultured on HAS DE the cells viability increased later in time. Alkaline phosphate activity was the highest for the cells cultured on HAS sample and statistically higher than for the MA sample. The least activity occurred on the smooth MA sample along with the rougher HAS DE samples. All the examined samples were found to be biocompatible, as indicated by cell attachment, proliferation, and differentiation. Titanium surfaces modification improved the dynamics of osteoblast viability increase. Osteoblast differentiation was found to be affected by the etching procedure and presence of Ca and P on the surface.

Oral health status and dental treatment needs of psoriatic patients with different therapy regimes.

The aim of the study was to investigate the dental treatment requirements and oral health status of psoriatic patients with different severities of the disease, managed by different methods, including biological therapies. METHODS: One hundred and twenty-seven patients diagnosed with psoriasis were enrolled in this study. All subjects completed a general medical history and a Dermatology Life Quality Index (DLQI) questionnaire. The severity of the disease was assessed using the Psoriasis Area and Severity Index (PASI) scale and a DLQI questionnaire. In order to evaluate the oral health status, the following techniques were used: Approximal Plaque Index (API), the Community Periodontal Index (CPI) and the Decayed, Missing and Filled Teeth (DMFT) index. RESULTS: Patients treated with biologicals presented a significantly lower mean CPI index and required no surgical interventions. Subjects managed with topical therapy had significantly more decayed teeth and higher treatment needs. Only 11.3% of patients did not require dental intervention. CONCLUSIONS: The study revealed a high need for dental interventions in patients with psoriasis. The type of treatment used may affect the oral health status of patients. However, further investigations are required to explain the significantly lower CPI value in the group treated with biologicals.

Laboratory and clinical evaluation of polymer materials reinforced by fibers used in dentistry.

OBJECTIVE: Fiber-reinforced composites (FRC) because of high strength and a low mass can be widely applied in many fields of dentistry. MATERIALS AND METHODS: The types of fibers commonly used in dentistry with the description of physicochemical properties of the reinforcing phase and polymer resin, are specified. The influence of the method of fiber positioning in the sample, their diameter, length and shape of fibers visible in cross-section on the strength of the FRC material, are underlined. The work also paid attention to the volume of the material that occurs as a result of the absorption of water from the oral environment and changes in bonding between matrix and fiber. RESULTS: The clinical procedures and a description of failures that may possibly happen in the oral cavity presented in the work, confirm that they allow fabrication of minimally invasive, lightweight, durable and biocompatible materials. At the moment, the only material group that can be used by direct technique to reach high load-bearing capacity restorations is FRC. CONCLUSIONS: Long-term treatment effectiveness makes FRCs an alternative to prosthetic restorations whose retention is obtained only as a result of mechanically interlocking to the abutment tooth. The use of FRCs in clinical dentistry is part of value-based medicine.

Cationic porphyrin-mediated photodynamic inactivation of Candida biofilms and the effect of miconazole.

The formation of biofilms by Candida and the increasing resistance of Candida species to antifungals contribute to the high recurrence rates of denture stomatitis. This increase has stimulated an interest in antimicrobial photodynamic therapy (aPDT) as an alternative treatment. We examined the photoactivity of the porphyrin-based photosensitizer, TMP-1363, against biofilms of C. albicans, C. glabrata, C. tropicalis and C. parapsilosis, and the effect of the combined use of miconazole and aPDT. Biofilms of three American Type Culture Collection (ATCC) strains and four clinical isolates developed on poly(methyl methacrylate) (PMMA) disks, were incubated with miconazole, followed by treatment with TMP-1363 for 30 min at 37°C. The plates were exposed to broadband visible light at a distance of 10 cm to the plate, for 30 min (irradiance at the surface of the plate: 32.5 mW/cm2). The metabolic activity of the biofilms was measured by the XTT assay. ATCC strains and C. glabrata 7531/06 were not sensitive to TMP-aPDT, whereas the metabolic activities of the remaining three clinical isolates were reduced to 64.2 ± 5.5% of controls. Miconazole at 25 µg/ml decreased the viability of all strains except the ATTCC strain C. albicans MYA274; however its combination with aPDT was effective against this strain, suggesting a synergistic interaction. Effects of miconazole and aPDT on C. albicans MYA 2732, C. albicans 6122/06 were additive. With C. tropicalis and C. parapsilosis, the combined treatment had a higher, but not entirely additive, cytotoxic effect. The combined use of miconazole and TMP-aPDT is advantageous in the treatment of biofilms of a number of Candida species and strains, but not all. The molecular basis of this differential response is not known.

Miconazole activity against Candida biofilms developed on acrylic discs.

Oral candidiasis in the form of Candida-associated denture stomatitis (CaDS) is associated with Candida adhesion and biofilm formation on the fitting surface of poly (methyl methacrylate) (PMMA) dentures. Candida biofilms show considerable resistance to most conventional antifungal agents, a phenomenon that is considered a developmental-phase-specific event that may help explain the high recurrence rates associated with CaDS. The aim of this study was to examine the activity of miconazole towards in vitro-grown mature Candida biofilms formed on heat-cured PMMA discs as a standardized model. The effect of miconazole nitrate on Candida biofilms developed on acrylic discs was determined for C. albicans MYA-2732 (ATCC), C. glabrata MYA-275 (ATCC), and clinical isolates, C. albicans 6122/06, C. glabrata 7531/06, C. tropicalis 8122/06, and C. parapsilosis 11375/07. Candida biofilms were developed on heat-cured poly(methyl methacrylate) discs and treated with miconazole (0.5 - 96 µg/ml). The metabolic activity of the biofilms was measured by the XTT reduction assay. The minimum inhibitory concentrations (MICs) of miconazole against Candida species were determined by the microdilution method. The MICs for miconazole for the investigated strains ranged from 0.016-32 µg/ml. Treatment with miconazole resulted in a significant reduction of biofilm metabolic activity for all strains. The highest inhibition was observed at 96 µg/ml miconazole. In the case of C. glabrata MYA-275 and C. tropicalis 8122/06 this corresponded to 83.7% and 75.4% inhibition, respectively. The lowest reduction was observed for C. parapsilosis 11375/07-46.1%. For all Candida strains there was a strong correlation between MIC values and miconazole concentrations corresponding to a reduction of metabolic activity of the biofilm by 50%. Miconazole exhibits high antifungal activity against Candida biofilms developed on the surface of PMMA discs. The study provides support for the use of miconazole as an effective agent for the treatment of CaDS.

Influence of antifungal polyenes on the adhesion of Candida albicans and Candida glabrata to human epithelial cells in vitro.

Candidal adherence to mucosal surfaces is considered as the first step in the pathogenesis of oral candidiasis. We examined the effect of antifungal polyenes, amphotericin B, nystatin and natamycin, at sublethal and minimum inhibitory concentrations (MICs) on the adherence of Candida albicans and Candida glabrata to HeLa cervical carcinoma and HSC-3 oral squamous cell carcinoma cells. A total of six oral Candida isolates were used throughout the study. Two Candida strains, C. albicans (44990) and C. glabrata (MYA-275) were obtained from ATCC. Four Candida strains, C. albicans 19 and 24 and C. glabrata 15 and 21, were isolated from patients with documented Candida-associated denture stomatitis. Cells were either incubated with Candida in the presence of the drug, or pre-incubated with yeasts and exposed subsequently to the drug. In the drug-free controls, the mean number of C. albicans yeasts associated with HeLa cells obtained from all experiments (130.1+/-10.1 yeasts/mm(2)) was significantly greater than that for HSC-3 cells (114.7+/-10.1 yeasts/mm(2); P<0.025). For C. glabrata, the mean adherence to HeLa and HSC-3 cells was 84.4+/-5.5 and 84.4+/-3.3 yeasts/mm(2), respectively, and these values were not statistically different (P>0.4). Candidal adherence was significantly reduced when the tested polyenes were present during the "adherence phase". The obtained values were significantly different from the controls, except for the effect of nystatin at the MIC on the adherence of C. glabrata strain MYA-275 to HeLa cells (P<0.375). Amphotericin B had the highest effect against both Candida species, reducing adherence by approximately 50 and approximately 60%, at the MIC and sublethal concentrations, respectively. The susceptibility of cell-associated Candida to polyenes was decreased markedly and the treatment did not result in significant detachment of adherent yeasts. The reduction in adherence was between 2 and 10%, when compared to the drug-free controls. These findings suggest that sub-therapeutic levels of polyenes that are likely to persist in the oral cavity following topical treatment may modulate candidal colonization when present during the "adherence phase".

Non-insulin-dependent diabetes mellitus as a risk factor for denture stomatitis.

The prevalence of denture stomatitis as well as the frequency of isolation of Candida species and their density on the palatal mucosa have been compared in 70 acrylic denture-wearers suffering from non-insulin-dependent diabetes mellitus (NIDDM) versus 58 acrylic denture-wearers with normal glucose metabolism. The adherence of C. albicans to palatal epithelial cells in vitro was also assessed in both groups. The patients with NIDDM had a significantly higher prevalence of denture stomatitis compared with the controls. The frequency of Candida colonization was increased in diabetics, but not significantly. According to the imprint culture technique, the density of Candida species was significantly higher in patients with NIDDM compared with the controls. The adherence of C. albicans to palatal epithelial cells from patients with NIDDM showed a significant increase compared with that observed in cells collected from the controls. This study supports the view that NIDDM predisposes to Candida-associated denture stomatitis.