Positive effect of platelet rich fibrin on osseointegration.

BACKGROUND: Leukocyte-platelet rich fibrin (L-PRF) is a second generation platelet concentrate clinically used to accelerate tissue healing and bone regeneration. Achieving reduced implant osseointegration time could provide immediate or early loading of implants. The aim of this study was to evaluate the L-PRF-induced osseointegration and bone-implant contact (BIC) in an experimental animal model. MATERIAL AND METHODS: Twelve 4-month-old New Zealand white rabbits were used. Following general anesthesia, 3-5 mL of blood was obtained from the central artery in rabbit ear and L-PRF was prepared. Two implant cavities (5 mm long and 3 mm in diameter) were created in each tibia with a total of four cavities in each animal. Two of these cavities were selected and covered with PRF (test group). The remaining L-PRF was used to soak the implants placed into the L-PRF covered sockets. Other cavities were left as controls. In total, 48 implants were placed. Animals were sacrificed after two, three, or four weeks. Histological samples were obtained and peri-implant tissues were histomorphometrically evaluated for bone-to-implant contact and new bone formation. RESULTS: Histomorphometric analyses of the defects revealed that the L-PRF was detectable up to the second week. Application of L-PRF increased the rate and amount of new bone formation in the experimental group compared to the control group. Bone-to-implant contact was enhanced when the surface was pre-wetted with L-PRF (p<0.01). CONCLUSIONS: The results of this study demonstrated that L-PRF application may increases amount and rate of new bone formation during the early healing period and provides a faster osseointegration around implants.

Cigarette smoking and apoptosis.

BACKGROUND: Epithelial cell hyperplasia and significant increase in thickness of the overlying orthokeratin layer are characteristic findings noted in the oral cavity of subjects who smoke. Increased proliferation of epithelial cells or defective apoptosis may play a role in the development of epithelial hyperplasia. Thus we analyzed soluble Fas and nuclear matrix protein (NMP) levels in the saliva of smokers (N = 13) and non-smokers (N = 14) to assess apoptosis. METHODS: Ten ml of unstimulated saliva samples was obtained from 14 non-smoker and 13 smoker subjects with the spitting method. These samples were analyzed by using an immunoassay kit to detect soluble human APO-1/Fas and cell death detection enzyme-linked immunosorbent assay (ELISA) kit based on nuclear matrix protein 41/7 qualification. RESULTS: The mean soluble Fas levels were 153.8 +/- 290 pg/ml and 315.4 +/- 490 pg/ml and NMP levels were 21.81 +/- 10.70 U/ml and 30.31 +/- 19.86 U/ml, respectively, in smokers and nonsmokers. The difference between NMP levels of smoker and non-smoker groups was statistically significant (P = 0.05). CONCLUSION: The results of the present study suggest that smoking may induce anti-apoptotic mechanism in the oral cavity.

Chitosan film enriched with an antioxidant agent, taurine, in fenestration defects.

A natural polysaccharide, chitosan (poly-N-acetyl glucosaminoglycan), which is a nontoxic and bioabsorbable polymer, has been shown to have hemostatic and antibacterial effects. An amino acid, taurine, is considered to be beneficial for regulating the inflammation process. The purpose of this study was to investigate the synergistic effects of taurine and chitosan in the experimental defects at the vestibular bone of maxillary canine teeth in six dogs. Chitosan films were prepared as delivery system with or without taurine and placed in the randomly chosen defects. Biopsies were performed on the postoperative seventh day and routine histological procedures were performed for light and electron microscopic evaluations. For each group, 30 different microscopic areas were examined and the numbers of macrophages and neutrophils in these areas were counted. The mean numbers of both macrophages and neutrophils were found statistically different between the chitosan film incorporated with taurine and free chitosan groups (p < 0.0001 p > 0.05). In addition to the increase in cell counts in both groups, the cytological alterations were more obvious in the chitosan film group incorporated with taurine. Accordingly, taurine appears to enhance the acceleration effect of chitosan on wound healing at early periods. This effect could be considered beneficial in tissue repair in destructive diseases like periodontitis.