Sinem Yeniyol

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.

The effect of drilling speed on early bone healing to oral implants

OBJECTIVE This study evaluated the effect of drilling speed on early bone healing in dog tibiae. STUDY DESIGN Thirty-six implants (4.0-mm diameter × 10-mm length) were placed in the proximal tibiae of 6 beagles with drilling speeds of 100, 500, and 1000 rpm, and insertion torque was recorded. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were evaluated. RESULTS Significant increase from 1 to 3 weeks was observed for all groups for BIC, whereas no significant differences between 1 and 3 weeks were detected for the 100- and 500-rpm groups for BAFO (P > .34 and P > .46, respectively). A significant difference from 1 to 3 weeks was observed for the 1000-rpm group (P < .03). The 100- and 500-rpm groups presented significantly higher BAFO than the 1000-rpm group at 1 week (P = .002). CONCLUSIONS Drilling speed is one of the decisive factors for early osseointegration, and overall, drilling at 1000 rpm seemed to yield the strongest biologic responses.

Antibacterial activity of As-annealed TiO2 nanotubes doped with Ag nanoparticles against periodontal pathogens

It is important to develop functional transmucosal implant surfaces that reduce the number of initially adhering bacteria and they need to be modified to improve the anti-bacterial performance. Commercially pure Ti sheets were anodized in an electrolyte containing ethylene glycol, distilled water and ammonium fluoride at room temperature to produce TiO2 nanotubes. These structures were then annealed at 450°C to transform them to anatase. As-annealed TiO2 nanotubes were then treated in an electrolyte containing 80.7 g/L NiSO4 ·7H2O, 41 g/L MgSO4 ·7H2O, 45 g/L H3BO3, and 1.44 g/L Ag2SO4 at 20°C by the application of 9 V AC voltage for doping them with silver. As-annealed TiO2 nanotubes and as-annealed Ag doped TiO2 nanotubes were evaluated by SEM, FESEM, and XRD. Antibacterial activity was assessed by determining the adherence of A. actinomycetemcomitans, T. forsythia, and C. rectus to the surface of the nanotubes. Bacterial morphology was examined using an SEM. As-annealed Ag doped TiO2 nanotubes revealed intense peak of Ag. Bacterial death against the as-annealed Ag doped TiO2 nanotubes were detected against A. actinomycetemcomitans, T. forsythia, and C. rectus indicating antibacterial efficacy.

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.

Production and Precipitation Hardening of Beta-Type Ti-35Nb-10Cu Alloy Foam for Implant Applications

In this study, beta-type Ti-35Nb-10Cu alloy foams were produced by powder metallurgy method for dental implant applications. 35% Nb was added to stabilize the beta-Ti phase with low Young’s modulus. Cu addition enhanced sinterability and gave precipitation hardening capacity to the alloy. Sintered specimens were precipitation hardened in order to enhance the mechanical properties. Electrochemical corrosion behavior of the specimens was examined by electrochemical impedance spectroscopy in artificial saliva. Electrochemical impedance spectroscopy results indicated that the oxide film on the surface of foam is a bi-layer structure consisting of outer porous layer and inner barrier layer. Impedance values of barrier layer were higher than porous layer. Corrosion resistance of specimens decreased at high fluoride concentrations and at low pH of artificial saliva. Corrosion resistance of alloys was slightly decreased with aging. Mechanical properties, microstructure, and surface roughness of the specimens were also examined.

Enhanced Bone Bonding to Nanotextured Implant Surfaces at a Short Healing Period : A Biomechanical Tensile Testing in the Rat Femur

Purpose:To compare the bone bonding capabilities of 2 different surface treatments at an early healing period. Titanium alloy (Ti6Al4V) custom-made rectangular plates (1.4 × 2.4 × 4 mm) were either dual acid etched (Ti6Al4V–DAE) or nanotextured proprietary processed Ti6Al4V–Ossean (intra-Lock International, Boca Raton, FL). Materials and Methods:Implants were placed in the distal femurs of 10 Wistar rats and were allowed to heal for 9 days. After euthanasia, the bone immediately proximal and distal to the implant was removed to test the bone bonding force with a universal testing machine. Ultrastructure of the bone/implant interface was assessed by scanning electron microscopy. Results:Ti6Al4V–NTB samples exhibited significantly greater bond strength than Ti6Al4V–DAE samples. Morphologically, the Ti6Al4V–Ossean surfaces presented intimate interaction with bone, whereas little interaction between the Ti6Al4V–DAE surface and bone was observed. Conclusion:The results of this study indicated a significant increase in bone bonding for the Ossean surface, which is suggested to be the outcome of the nanotexturing.

Photocatalytical Antibacterial Activity of Mixed-Phase TiO2 Nanocomposite Thin Films against Aggregatibacter actinomycetemcomitans.

Mixed-phase TiO2 nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). The topology was assessed by White Light Optical Profiling (WLOP) in the Vertical Scanning Interferometer (VSI) mode. Representative height descriptive parameters of roughness R a and R z were calculated. The photocatalytic activity of the resulting TiO2 films was evaluated by the photodegradation of Rhodamine B (RhB) dye solution. The antibacterial ability of the photocatalyst was examined by  Aggregatibacter actinomycetemcomitans suspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phase TiO2 thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively. Craters (2–5 µm) and protruding hills (10–50 µm) on Ti substrates were produced after electrochemical anodization with higher R a and R z surface roughness values. Anatase/rutile mixed-phase TiO2 thin films showed 26% photocatalytic decolorization toward RhB dye solution. The number of colonizing bacteria on anatase/rutile mixed-phase TiO2 thin films was decreased significantly in vitro. The photocatalyst was effective against A. actinomycetemcomitans colonization.

Characterisation of corrosion properties of Ti–Nb–Cu alloy foam by electrochemical impedance spectroscopy method

In the present study, highly porous Ti–Nb–Cu alloy foams were produced by a powder metallurgy method for biomedical implant (hard tissue) applications. Nb was added in order to stabilize the beta-Ti phase. Cu addition enhanced sinterability and reduced the sintering temperature of the alloy. Electrochemical corrosion behaviour of the Ti–Nb–Cu alloy specimens was examined by the electrochemical impedance spectroscopy method in an artificial saliva environment. Effects of porosity of the foam, Cu content of the alloy, pH and fluoride content of the artificial saliva solution on the electrochemical corrosion properties of the specimens were investigated. Mechanical properties of the specimens were also studied by compression tests.

Full Mouth Oral Rehabilitation by Maxillary Implant Supported Hybrid Denture Employing a Fiber Reinforced Material Instead of Conventional PMMA.

Many people have life-long problems with their dentures, such as difficulties with speaking and eating, loose denture, and sore mouth syndrome. The evolution of dental implant supported prosthesis gives these patients normal healthy life for their functional and esthetic advantages. This case report presents the fabrication of maxillary implant supported hybrid prosthesis by using Nanofilled Composite (NFC) material in teeth construction to rehabilitate a complete denture wearer patient.

Alkaline phosphatase levels of murine pre-osteoblastic cells on anodized and annealed titanium surfaces

Purpose This study aimed to evaluate the initial adhesion morphology and alkaline phosphatase (ALP) activity of murine pre-osteoblastic MC3T3-E1 cells cultured on anatase/rutile mixed-phase TiO2 thin films with photocatalytical activity with previously confirmed antibacterial properties. Materials and methods Anatase/rutile mixed-phase TiO2 thin films fabricated by anodization and annealing of cpTi were used to culture MC3T3-E1 cells to evaluate the initial cellular adhesion morphology and ALP activity in vitro. Results Compared with MC3T3-E1 cells cultured on cpTi substrates and the control group, cells cultured on anatase/rutile mixed-phase TiO2 thin films exhibited similar ALP levels after cell culture day 9. Conclusion Anodizing and annealing processes fabricate multifunctional surfaces on cpTi with improved osteogenic properties for implants.