A New Centrifugation Method for the Improvement of Platelet-rich Fibrin Products: A Preliminary Study.

Introduction: Nowadays, there are many articles about Platelet Rich Plasma/Platelet Rich Fibrin families. A novel platelet-rich product called titanium prepared platelet-rich fibrin (T-PRF) has stronger and thicker fibrin than that of the classic glass tube prepared platelet-rich fibrin. Strong fibrin structure is important to extend the time for resorption of fibrin in-vivo, and increase the release time of growth factors. Objective: In this preliminary study of a new centrifugation method, we aimed to change the direction of fibrin formation during the platelet aggregation, and make T-PRF much denser and more resistant. According to our hypothesis, it can make it possible to use in guided bone, and guided tissue regeneration more successfully. Methods: Blood samples of 10 healthy male volunteers were collected, and four 10ml blood samples, one for each of four groups, were transferred to a Ti tube from each volunteer. The first group was centrifuged for a 20-minute period clockwise (T-PRF group), and the other groups were centrifuged for a total of 20 minutes with two-minute (2min MT-PRF group), five-minute (5 min MT-PRF group), and ten-minute (10min MT-PRF group) periods clockwise and counter-clockwise. Results: By hematoxylin and eosin stain, the 10min MT-PRF group showed a better-organized network with continuous integrity compared to the other groups. With the immunofluorescent staining, fibrin seemed thicker and better organized in the 10 min MT-PRF group. SEM examination showed more complex and denser fibrin clusters in the 10 min MT-PRF group than the other groups. Conclusion: This pilot study defines 10 min MT-PRF as a new autogenous product with superior fibrin network. Our results showed that, fibrin formation was made more organised and denser with 2-way direction centrifugation.

Periodontal & systemic bone changes in rats with experimental lathyrism.

BACKGROUND & OBJECTIVE: It is not clear how lathyrism affects the systemic bone metabolism. We therefore undertook a study to observe periodontal and systemic bone changes by performing radiological, metabolic, and bone densitometric evaluations in rats with experimental lathyrism. METHODS: A total of 30 rats were used. Experimental lathyrism was induced by once daily subcutaneous administration of beta-aminopropionitrile (beta-APN), at a dose of 5 mg beta-APN/0.4 ml per 100 g of body weight for 40 days. After 40 days, vertebral bone mineral density was analyzed by means of dual energy X-ray absorbtiometry in both groups. Blood was drawn by cardiac puncture and the animals were decapitated. Serum calcium levels were measured. Right mandibles were removed and radiographs were obtained. Alveolar bone level was determined in the radiographs. RESULTS: In all lathyritic rats, alveolar bone level was pathologically decreased with visible resorption. Vertebral bone mineral density values of lathyritic rats did not differ significantly from those of the control group. Compared to controls, there was a statistically significant decrease in serum calcium levels in the lathyritic group (P<0.001). INTERPRETATION & CONCLUSION: Significant alveolar bone resorption without alterations in vertebral bone mineral density indicated that lathyrogen administration for 40 days presumably has not caused systemic demineralization. This model could be used for studying the role of local and systemic agents on periodontal alveolar bone resorption.

Determination of systemically & locally induced periodontal defects in rats.

BACKGROUND & OBJECTIVE: The role of lathyrogens on bone metabolism is unclear, therefore we undertook this study to observe periodontal and systemic alterations in experimental lathyrism in rat and compare these changes to that observed in the locally induced periodontitis group. METHODS: A total of 45 male Wistar rats were equally divided in the lathyritic group (group 1), ligature-induced periodontitis group (group 2), and healthy controls (group 3). Experimental lathyrism was induced by once daily subcutaneous administration of beta-aminoproprionitrile (beta-APN), at a dose of 5 mg/0.4 ml per 100 g of body weight for 40 days. Ligature-induced periodontitis was created by tying silk ligatures on the necks of mandibular molars. After 40 days, blood samples were obtained and the animals were decapitated. Radiographic observations, extraction tests, histologic evaluations were performed, and serum ALP activity and gingival tissue IL-1beta levels were measured. RESULTS: Significant alveolar bone resorption around the mandibular molar teeth (P<0.001); lower extraction force levels (P<0.001); higher numbers of lymphocytes and macrophages (P<0.01) (both in connective tissue and epithelium at the dentogingival junction); decreased ALP activity (P<0.001); and increased gingival tissue IL-1beta levels (P<0.001) were observed in groups 1 and 2, compared to those in group 3. ALP activity was higher in group 1 than in group 2 rats (P<0.05). INTERPRETATION & CONCLUSION: Similar radiographical and histopathological findings and comparable increases in gingival tissue IL-1beta levels both in groups 1 and 2 showed that in addition to resorption of alveolar bone, chronic inflammation of periodontium also occurred both in the lathyritic rats as well as in ligature-induced periodontitis group rats.