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.

The effect of platelet-rich fibrin on implant stability.

PURPOSE: Achieving accelerated implant osseointegration could make immediate or early loading of implants more predictable. Platelet-rich fibrin (PRF) is frequently used to accelerate soft and hard tissue healing. The activated platelets in PRF release growth factors, resulting in cellular proliferation, collagen synthesis, and osteoid production. The aim of this study was to compare the stability of dental implants inserted in a one-stage surgical protocol with or without PRF application. MATERIALS AND METHODS: Twenty healthy patients with adequate alveolar bone and two or more adjacent missing teeth extracted at least 6 months previously were included in this study. A minimum of two tapered implants (Ankylos, Dentsply/Friadent) were placed in each patient. After surgical preparation of the implant sockets, PRF that had been prepared preoperatively was placed randomly into one of the sockets (PRF+). The acellular plasma portion of PRF was used to wet the implant placed into the PRF-coated socket. Resonance frequency measurements were made after implant placement and at 1 week and 1 month postoperatively. RESULTS: Mean implant stability quotients (ISQs) of the PRF+ implants was 69.3 ± 10.5, and mean ISQs for the PRF- implants was 64.5 ± 12.2 at the end of the first week. The mean ISQs at 4 weeks postoperatively were 77.1 ± 7.1 for the PRF+ group and 70.5 ± 7.7 for the PRF- group. CONCLUSION: In this study, PRF application increased implant stability during the early healing period, as evidenced by higher ISQ values. Simple application of this material seems to provide faster osseointegration.

Combined use of alveolar distraction osteogenesis and segmental osteotomy in anterior vertical ridge augmentation.

INTRODUCTION: Vertical defects of the anterioral veolar ridge are challenging cases in implant dentistry. Various techniques, such as onlay bone grafting, segmental osteotomy (SO) oral veolar distraction osteogenesis (ADO), have been suggested to manage those situations. ADO has an advantage of being capable of enhancing both hard and soft tissue simultaneously. PRESENTATION OF CASE: One of the possible complications of ADO is rotation ortilting the transport segment (TS). In this report, we present a 30-year old woman who had a severe anterior vertical deficiency. ADO was started to manage the case, but advancement of the TS lagged on the left side and the segment rotated. A SO was planned and the lagged side was corrected. Two years after the surgery, hard and soft tissue gains were found to be preserved. DISCUSSION: Vertical alveolar bone deficiencies are challenging cases for dental implantology. Alveolar DO promotes soft tissue along with hard tissue, and the bone regeneration process and shows lower infection rates and greater stability over the long term. However, the technique has some disadvantages and can lead to complications, such as breaking of the distraction device, nerve injury or paresthesia, fracture of transport bone, hematoma, wound dehiscence, severe bleeding, and even jaw fractures. Deviation of the TS from the distraction path is another undesired situation. The rigidity of the device, the width of the mucosa, the volume of the transport and anchor segments, and the amount of augmentation can affect vector deviation. CONCLUSION: We suggest that SO can be used in similar cases in which TS could not be distracted on a straight vector line.

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.

In vitro/in vivo studies on a buccal bioadhesive tablet formulation of carbamazepine.

A buccoadhesive controlled-release system for delivery of carbamazepine (CBZ) was prepared by compression of hydroxypropyl methylcellulose (HPMC) and carbomer, incorporating a penetration enhancer, sodium glycodeoxycholate (GDC). The release behaviour of systems containing CBZ and various amounts of the two polymers with and without GDC was found to be non-Fickian. Formation of an interpolymer complex between HPMC and carbomer was confirmed in acidic medium by turbidity, viscosity and FT-IR measurements. Addition of the drug to the buccoadhesive formulation reduced the adhesion force significantly (p < 0.1). GDC did not have any effect on bioadhesion. Permeability of bovine buccal mucosa to CBZ was determined using Ussing diffusion chambers [1]. In vivo interaction between the tablet and tissue was examined histologically as well as by scoring mucosal irritation. Histological changes observed in the buccal epithelium after 4 h contact with the tablets containing GDC recovered completely within 24 h after removal. No measurable plasma level of CBZ was obtained either in the absence or presence of GDC.

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.