Nilüfer Bölükbaşı

The Use of Platelet-Rich Fibrin in Combination With Biphasic Calcium Phosphate in the Treatment of Bone Defects: A Histologic and Histomorphometric Study

Background Platelet-rich fibrin (PRF) is a leukocyte and platelet concentrate containing many growth factors. Its potential for hard tissue augmentation as a sole grafting material or in combination with other grafting materials has been investigated in many studies. Objective The aim of this histologic study was to evaluate the efficacy of PRF mixed with biphasic calcium phosphate (BCP) on bone regeneration in surgically created bone defects. Methods Defects 5 mm in diameter were created in both tibias of 6 sheep. The defects were left empty or grafted with BCP, PRF, or BCP+PRF. Animals were killed at 10, 20, and 40 days. The specimens underwent histologic and histomorphometric analysis. Results None of the groups displayed any signs of necrosis. Inflammation was observed in all groups at 10 days; 2 specimens of PRF+BCP and all empty defects showed inflammatory cell infiltration at 20 days. During the 40-day evaluation period, the PRF+BCP group showed the highest ratios of new bone. The other 3 groups showed statistically similar results. In the BCP and PRF+BCP groups, the residual graft ratios were decreased at consecutive time intervals. The difference between the 2 groups was not statistically significant during follow-up. Conclusions The current study revealed a histomorphometric increase in bone formation with the addition of PRF to BCP in surgically created defects in sheep tibia.

Bacteremia following dental implant surgery: Preliminary results

Objectives: The aims of this study were to investigate the incidence of bacteremia, bacteriology and antibiotic susceptibility against to causative bacteria associated with dental implant installation. Study Design: 30 generally healthy patients were enrolled in this study. Blood samples were collected at baseline and at 30 minutes after dental implant installation and 24 hours after dental implant surgery. Blood samples were cultured in a BACTEC system. The isolated bacteria were identified using conventional methods. Antimicrobial sensitivity tests were performed by disc diffusion. Results: No bacteria were isolated at the baseline and 24 hours after surgery, whereas the prevalence of bacteremia at 30 minutes after dental implant installation was 23%. The isolated bacteria species were Staphylococcus epidermidis, Eubacterium spp., Corynebacterium spp. and Streptococcus viridans. The Staphylococcus epidermidis, which was isolated in three patients, was found to be resistant to penicillin which is first choice of many clinicians. Conclusion: Our findings suggest that installation of dental implants can produce bacteremia. Within the limitations of this study, it can be speculated that the resistance of antibiotics may compromise the routine prophylaxis against infective endocarditis. Therefore use of blood cultures and antibiograms may be suggested in risky patients. The outcome of the present study should be verified using a larger patient group with varying conditions. Key words: Dental implant, bacteremia, infective endocarditis, antibiotic prophylaxis.

Relative Contributions of Surface Roughness and Crystalline Structure to the Biocompatibility of Titanium Nitride and Titanium Oxide Coatings Deposited by PVD and TPS Coatings

This study was conducted to characterize titanium (Ti) metal surfaces modified by polishing, coating with titanium nitride, coating with titanium oxide, sandblasting with alumina (Al2O3) particles and coating with titanium oxide, coating with titanium plasma spray (TPS); and to evaluate the effect of surface roughness and crystalline structure on adhesion of human fetal osteoblast cells (CRL-11372) in vitro after 24 hours. Surface topography and roughness were examined by scanning electron microscopy (SEM) and a noncontacting optical profilometer, respectively. The crystalline structures of the coatings were characterized by X-ray diffraction (XRD). CRL-11372 cells were incubated at these surfaces for 24 h and were evaluated for their mean total cell counts and cell viabilities. Cell morphologies were examined qualitatively by SEM images. Glass discs served as control group (CG) for the cell culture experiments. Surfaces at the Group TPS had the highest and values. Highest mean total cell counts were found for the CG. SC (sandblasted and TiO2 coated) surfaces had shown sparsely oriented CRL-11372 cells while other surfaces and CG showed confluency. Surfaces displayed diverse crystalline structures. Crystalline structures led to different cellular adhesion responses among the groups regardless of the surface roughness values.

Sinus Augmentation With Platelet-Rich Fibrin in Combination With Bovine Bone Graft Versus Bovine Bone Graft in Combination With Collagen Membrane

The purpose of this study was to compare the efficacy between the use of bovine bone graft material and platelet-rich fibrin (PRF) mixture (test group) and bovine bone graft material and collagen membrane combination (control group) in 2-stage maxillary sinus augmentation. According to specific inclusion/exclusion criteria, patients treated between 2008 and 2012 were selected. Panoramic radiographs were used for radiologic assessments. To evaluate the relationship between sinus-graft height and each implant, the bone level (BL) was divided by implant length (IL). To evaluate the change in the height of grafted sinus, the grafted sinus floor above the lowest part of the original sinus height (GSH) was divided by the original sinus height (OSH). Samples taken during implant surgery were used for histologic and histomorphometric analyses. Twenty-five patients, 32 augmentation surgeries, and 66 one-stage implants were included in the study. No implant loss or complication was observed in either group. There were no statistical differences according to new bone formation (P = .61) and biomaterial remnant (P = .87). During the evaluation period, the test group showed statistically less change in the BL/IL ratio (P = .022). The difference of GSH/OSH ratio was found to be insignificant between groups (P = .093). It was observed that the grafted sinus covering the implant apex and sinus floor was above the original sinus height in both groups. It may be concluded from this study that both combinations can be successfully used for sinus augmentation. Further studies evaluating different graft materials and PRF combinations in the early phases of healing would be beneficial.

Topical single-dose vascular endothelial growth factor has no effect on soft tissue healing

Background: Vascular endothelial growth factor (VEGF) production in dermal wounds has been evaluated for evidence that it plays a probable role in wound healing. Events such as increased vascular permeability and concentration of inflammatory cells on the site of injury, produced by VEGF, were linked to tissue repair. Aim: The present study aimed to evaluate the effects of single-dose topical administration of VEGF on wound healing. Materials and Methods: A total of 30 male Wistar albino rats weighing 250-280 g were used in this study. In addition, 2-cm-long skin incisions were created over bilaterally exposed skin of the tibia region in each rat. VEGF plasmid 2 μg was administered locally into the right side wound bed of each animal. No other procedure besides skin closure was administered on the left side. To determine histologic assessments, skin samples were obtained from six anesthetized rats at each interval (4, 8, 12, 16 and 30 days) through excisional biopsy. The tissues were fixed in 10% neutral-buffered formalin for 1 week and then embedded in paraffin wax. Transverse sections of the embedded tissue 5-7 μm thick were stained with hematoxylin and eosin (H and E). Results: There was no significant difference regarding necrosis, epithelialization, inflammation, fibroblast activity, ulcerative formation, or hemorrhage between experimental and control groups. No statistically significant difference was found between the groups regarding granulation tissue formation and epidermal thickness. Conclusion: The administration method and dosage of VEGF is a major factor in terms of its effectiveness. The results of the present study did not evaluate the effectiveness of single-dose 2 μg topical administration of VEGF; however, various doses of VEGF plasmid should be tested in future studies in order to provide beneficial effects from topical administration of VEGF.

Effects of Surface Modifications with Oxalic Acid Etching and Sandblasting on Surface Topography and Biocompatibility of cpTi Surfaces

ABSTRACT The objective of this study was to evaluate the topographical effects of titanium surfaces created by sandblasting and oxalic acid etching on the adhesion of human fetal osteoblast cells (CRL-11372) in vitro after 24 hours. Osteoblast cells were cultured on polished titanium (Ti) discs (Control Group), alumina (Al2O2) particle blasted and oxalic acid etched (20 min) Ti discs, oxalic acid etched polished Ti discs for 20 min, and oxalic acid etched Ti discs for 60 min. The topographies and roughness of the modified surfaces were assessed. Cell count, cell viability and morphologic differences between cells adhering to the modified surfaces were evaluated. The results showed that all surfaces, independent of surface roughness, favored cell adhesion with similar cell viabilities to that of the positive control group cells after 24 h. The highest Ra (average roughness) value was found for sandblasted and oxalic acid etched surfaces as 4.54 μm. Acid etching with 10 % oxalic acid after sandblasting did not eliminate residual alumina particles. Surface modification processes ended up with similar mean total cell counts with each other, even exhibiting no differences from the positive control group in terms of their cell viabilities. Oxalic acid etching and sandblasting surface treatments represented in our study increased the surface roughness values and allowed adhesion of the CRL-11372 cells after 24 h of incubation.