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BACKGROUND: Platelet-rich fibrin (PRF) is used to prepare "sticky bone" by combining it with bone-graft material. The present study investigated the ability of different bone grafts to absorb growth factors from the PRF and release them over time. METHODS: Human blood was collected from 10 healthy volunteers for liquid PRF preparation. Bovine bone, allograft (mineralized and demineralized), and synthetic bone were each mixed with the PRF to prepare a sticky bone. All sticky bone samples were incubated for up to 4 days and the absorption and release pattern kinetics of two selective growth factors within the PRF (Platelet-Derived Growth Factor and bone morphogenetic protein 2) were quantified with immunofluorescence staining and ELISA. RESULTS: All the tested bone graft materials adsorbed the examined growth factors from the PRF. ß-TCP showed the highest adsorption levels, followed by the xenograft, and the allografts showed the lowest adsorption levels. Furthermore, PDGF showed a fast release pattern from the grafts, whereas BMP2 was released at a later stage. Similar to the adsorption pattern, the ß-TCP and xenograft were better able to sustain the release of the PRF growth factors from the graft than the allografts. CONCLUSIONS: The adsorption of PDGF and BMP2 differ between graft materials, with superior results for ßTCP, followed by xenograft and lastly the allograft materials.

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OBJECTIVE: To investigate the incorporation of the antifibrinolytic agent tranexamic acid (TA) during platelet-rich fibrin (PRF) formation to produce a robust fibrin agent with procoagulation properties. STUDY DESIGN: Blood from healthy volunteers was collected. Into 3 tubes, TA was immediately added in 1-mL, 0.4-mL, and 0.2-mL volumes, and the fourth tube was without additions. After PRF preparation, the clots were weighed in their raw (clot) and membrane forms. PRF physical properties were analyzed using a universal testing system (Instron). Protein and TA levels in the PRF were analyzed using a bicinchoninic acid assay and a ferric chloride assay, respectively. RESULTS: The addition of TA to PRF led to a robust weight compared with sham control. PRF weight was greater in females in all tested groups. The addition of TA also led to greater resilience to tears, especially at 1-mL TA addition to the blood. Furthermore, TA addition led to a greater value of total protein within the PRF and entrapment of TA in the PRF. CONCLUSIONS: Addition of TA to a PRF preparation leads to robust PRF with greater protein levels and the amalgamation of TA into the PRF. Such an agent may enhance the beneficial properties of PRF and attribute procoagulation properties to it.

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PURPOSE: To evaluate the knowledge, opinions, and behaviours of physicians in the field of internal medicine and gynecology regarding periodontal disease and its systemic implications. METHODS: A questionnaire was distributed by hand and via e-mail to internists and gynecologists working in hospitals and community clinics. The questionnaires included items regarding personal and professional status, subject-related characteristics, dental history and knowledge in periodontal medicine. All completed questionnaires were reviewed and analysed according to discipline and personal experience. Statistical differences were tested using the chi-squared analysis. RESULTS: A total of 97 questionnaires were reviewed and included 56 internists and 41 gynecologists. The mean age was 39.7 years (range 29-82) and the percentage of females was 54%. Overall, general knowledge regarding periodontitis differed significantly between internists and gynecologists (80% vs 32% correct answers per group, respectively). Nearly 60% of responders (both internists and gynecologists) knew the correct cause of periodontal disease. Although half of the responders had personal experience in the field of periodontology, this experience was not noticeable regarding their knowledge in periodontal medicine. The majority of responders (58%) agreed that there is a need for more periodontal education in general medicine. CONCLUSIONS: The present study indicates a clear lack of knowledge of both internists and gynecologists regarding periodontitis and its systemic complications. Personal periodontal experience did not change the degree of familiarity with periodontal medicine.

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OBJECTIVE: To determine the effect of blue light on cultured splenocyte viability and secretion of cytokines involved in the regulation of immune responses in the inflammatory process. BACKGROUND DATA: Previous studies showed that red light has various effects on lymphocyte proliferation and production of cytokines. MATERIALS AND METHODS: Cultured mouse splenocytes were exposed to visible light (wavelengths, 450-490 nm) using 2-108 J/cm(2), with and without scavengers of reactive oxygen species (ROS). One half of the samples were stimulated by the heat-killed periopathogenic bacterium Porphyromonas gingivalis. Following incubation for 48 h, the levels of the cytokines interleukin-10 (IL-10), tumor necrosis factor alpha (TNFα), and interferon gamma (IFNγ) were analyzed, and the viability of the cells was tested using the XTT assay. The total oxidant-scavenging capacity of the nonexposed and exposed splenocytes to light was determined by a chemiluminescence assay, and the temperature of the cell culture medium was measured after light exposure. RESULTS: Exposure to blue light at fluences of 27-108 J/cm(2) caused a decrease in splenocyte viability. Lower fluences increased the secretion of cytokine IL-10, which was abolished by ROS scavengers. Exposure to light had no effect on the secretion of cytokines TNFα and IFNγ. Following exposure to light, more ROS were detected and the temperature measured did not exceed 30.7°C. CONCLUSIONS: Blue light had a stimulatory effect on cell secretion of IL-10, mediated by ROS. Therefore, an increase in IL-10 might be a potential method for modulating the inflammatory processes of local disorders, such as periodontitis and arthritis.

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PURPOSE: The aim of this study was to measure the increase in temperature in dental implants during the intake of hot beverages in vivo. MATERIALS AND METHODS: Eight successfully osseointegrated implants in 7 subjects were examined. Each subject was asked to drink the same volume of hot beverage. While drinking, temperature changes were recorded via 3 embedded thermocouples placed (i) in the implant's internal space, (ii) at the implant-abutment interface, and (iii) at the abutment. All thermocouples were linked to a computer and analyzed with appropriate software. RESULTS: The maximum temperatures were 47.3 degrees C at the abutment, 45.6 degrees C at the implant's internal space, and 44.6 degrees C at the implant-abutment interface. A linear correlation was found between the temperatures measured (i) at the implant abutment and in the implant's internal space, and (ii) at the abutment and at the abutment-implant interface. CONCLUSIONS: Further clinical studies are required to determine whether the habitual consumption of hot food and beverages may be considered a risk factor in the success of implant-supported prostheses.

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