Objectives: The purpose of the present study is to measure and monitor the levels of potential pro- inflammatory cytokine interleukin-1beta (IL-1β) Tumor necrosis factor-alpha (TNF-α) in Peri-implant crevicular fluid (PICF) for the level of activity of inflammatory processes during the various stages of implant delivery system.
Materials and Methods: A total of 12 dental implants were placed in nine partially edentulous patients (mean age of 60 years). External Branemark implants with anodic oxidized surface were installed and submerged in all the patients. The healing abutments were delivered at the second surgery and they were removed more than three times till the final prosthesis delivery. At different time points during the treatment, peri-implant cervicular fluid (PICF) was collected and pro-inflammatory cytokine (IL-1β and TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). The clinical indices were also recorded at every time point.
Results: The pro-inflammatory cytokine levels were different during different time points. Increased level of IL-1β levels during various stages of implant delivery. All the implants were Osseo integrated.
Conclusion: The findings of the present study indicated that level of IL-1beta, may be an important biomarker in addition to clinical findings in measuring the health condition of the peri-implant tissues.
The present study evaluated the influence of two different placement orientations of biomaterials on apatite deposition behaviors during immersion in simulated body fluid (SBF). Titanium (Ti) and thin carbonate-containing hydroxyapatite coated Ti (CA/Ti) were used as biomaterials, and Hank's balanced salt solution was employed as an SBF. Ti and CA/Ti disks were placed either horizontally or vertically. For the horizontal placement, the disks were placed directly on the bottom of the container. For the vertical placement, the disks were hung from a nylon wire. The medium and container were replaced every day. After immersion for 3, 7, and 14 days, the surface appearances of the horizontal or vertical sides of the Ti and CA/Ti disks were observed using a scanning electron microscope. Ti disks showed apatite deposition after 3 days of immersion with the horizontal placement, but few disks showed this with the vertical placement. The Ti surface of the horizontal side was completely covered with deposited apatite. Even after 7 and 14 days, the whole Ti surface of the vertical disk was not completely covered with deposited apatite. For CA/Ti, apatite deposition was clearly recognized after 3 days of immersion on the surfaces of not only the horizontal placement but also the vertical placement. Piled up apatite globules were observed on the horizontal surface, but no distinct piled up globules were observed on the vertical surface after 7 and 14 days of immersion. In conclusion, it revealed that apatite deposition and apatite crystal growth were influenced by the placement orientation of sample disks in SBF immersion experiments.
Platelet-rich fibrin (PRF) includes various growth factors, and it has been reported to stimulate hard and soft tissue healing. However, there have been very few articles discussing its histological features. In the present report, we observed core samples harvested from human maxilla bone augmented with artificial bone combined with PRF for sinus floor augmentation. The patient underwent sinus floor augmentation using artificial bone combined with PRF. When the second implant surgery was performed, cylindrical bone core samples were harvested from the augmented area. Samples were prepared using the non-decalcifying fresh-frozen section technique and were observed with a microscope. Histologically, we observed soft and hard tissue throughout the region observed. In the hard tissue area, new bone formation around the artificial bone particles and new bone invading the artificial bone were observed. The core sample harvested from maxilla augmented by artificial bone combined with PRF showed histologically active new bone formation.
It has been reported that plasma rich in growth factors (PRGF) is effective in clinical application, but the biological and histological details are still unknown. The purpose of this study was to examine a microstructure of PRGF by SEM. Venous blood was sampled from healthy volunteers and randomly divided the subjects into two groups, a blood clot group and a PRGF group. And the latter divided into three groups; a 0.5 mL layer placed above a buffy coat was set as Fraction 3 (F3), the 0.5 mL layer above F3 was Fraction 2 (F2), and the layer above F2 was the remaining blood serum component of Fraction 1 (F1). PRGF group hemocytes other than thrombocytes were not observed, and the surface of thrombocytes were smooth. In addition, platelet aggregation was not observed. PRGF group showed thin fibers densely arranged and a dense fibrin network and the pore size of the meshwork was smaller than platelets. This microstructure shows that PRGF is easy to entangle among the mesh of the fibrin network even without formation of platelet aggregates and it plays a role as a scaffold.
In the present study, bone regeneration using gelatin/calcium phosphate (CaP) paste with different degradation rates of gelatin was evaluated after implantation into the cortical bone of rabbit tibiae with a bone healing process. Three types of gelatin: gelatin SL (smaller size and low degree of cross-linking), gelatin LL (larger size and low degree of cross-linking), and gelatin LH (larger size and higher degree of cross-linking) were prepared. A powder mixture of each gelatin and CaP was mixed with a liquid. The mixed paste was filled into cortical bone defects of rabbit tibia. As a control, CaP paste without gelatin was used. After 12 weeks of implantation, bone response was evaluated by preparing non-decalcified thin sections. In the control, new bone formation was recognized but much amount of remaining CaP particles was clearly observed inside the newly formed bone besides in the bone defect area. For gelatin SL/CaP and LL/CaP, more than half of the space of the bone defect was filled with new bone. Degradation residues of gelatin were recognized in the bone marrow side of the bone defect and small amounts of CaP particles were remained in the gelatin residue. For gelatin LL/CaP, new bone formation was also observed, but residual gelatin degradation was not clearly identified, and greater amounts of remaining CaP particles was recognized. In conclusion, it revealed that present gelatin/CaP pastes promoted new bone formation. The present gelatin/CaP paste should be useful as a bone regenerative material.
Dental silver alloys, such as gold-silver-palladium and silver-tin alloys, are frequently used in dental practice. These alloys are examined for biological safety as medical equipment. However, their embryotoxicity in normal newborns has not been investigated. We have reported the embryotoxicity risks of alloys upon their corrosion in the oral cavity, which are different from those of their composition metals. In the present study, four types of silver alloys were examined for ES cell differentiation on their surfaces corroded with human or artificial saliva. In addition, the alloy surfaces were examined by physical scratching and further erosion in dilute hydrochloric or sulfuric acid, because the dental gold-silver-palladium alloy surfaces are resistant to natural corrosion. As a result, chemicals generated upon corrosion of the four kinds of dental silver alloys may have embryotoxicity risks, unlike those immediately after casting.
Bone defects are common in craniofacial surgery and orthopedics. Autogenous bone grafting involves a second surgery and is limited by availability of collectable bone. Therefore, bioabsorbable scaffolds with superior handling characteristics for surgical applications are required, which are replaceable by autologous tissue. We constructed collagen model polypeptides comprising a poly(PHG) made by polycondensation of Pro-Hyp-Gly and porous alpha-tricalcium phosphate (α-TCP) sponge as scaffold, by dehydrothermal crosslinking, and examined them on surgically formed canine mandibular bone defects. At 2 and 4 weeks post- implantation, bone volumetric densities (VD) for the poly(PHG)/α-TCP group were higher than those for poly(PHG) and no-implant groups. Difference in VD was insignificant among the three groups 8 weeks post-implantation. Histological evaluation 4 weeks post-implantation revealed degraded poly(PHG) and newly formed bone on the α-TCP particle surfaces. At 8 weeks post-implantation, continuous cortical bone formation with Haversian structure was observed in both implant groups. Therefore, this composite can be applied in bone defect treatment.
When performing mandibular reconstructive surgery, differences between the curve of the mandible and straight bone graft often affect the suiting of the mandible reconstruction plate, making the suiting of the bone graft to the mandible difficult. Poor plate-to-bone suitability affects postoperative mastication, leading to a marked decrease in the postoperative quality of life. In response to this problem, we used 3-dimensional models of the donor bone and mandible to reproduce the shape of the reconstructed mandible before surgery. Based on this model, we then used surgical measures, such as creating a surgical guide plate, to reproduce the curvature of the mandibular reconstruction plate and mandibular position and occlusion. Of thirteen patients who underwent mandibular reconstruction using this method at our hospital, evaluation was possible for ten patients. These patients underwent evaluation of functions, including masticatory performance and occlusal force. Results showed that masticatory function was maintained at a high level using this method, indicating a good bone suitability.
High-frequency electromagnetic wave stimulation induces proliferation and differentiation of osteoblasts. The aim of the study is to histopathologically evaluate the effects of high-frequency electromagnetic waves on bone formation.
Bone defects with a diameter of 4.8 mm were created on the left and right sides of the calvarias of Wistar rats. The active electrode was placed in the left defect and high-frequency electromagnetic stimulus was applied for 1 s and repeated five times. This was performed twice a week for 2 weeks. The right defects were not stimulated (control group). After 8 weeks, histological specimens were prepared by hematoxylin and eosin (HE) staining, and the rate of bone formation was measured.
The rate of bone formation was significantly larger in the experimental group than in the control group. These results indicate that high-frequency electromagnetic wave stimulation enhances bone formation in rat calvarial defects.
The purpose of this study was to evaluate the effects of aging on bone formation induced by Bone Morphogenetic Protein-2 (BMP-2) using low-intensity pulsed ultrasound (LIPUS)in 12-week-old (12w group) and 70-week-old (70w group) Wistar rats.
The experimental sites (palatal subperiosteal sites) were divided into three sites as follows: BMP site, BMP-2 was implanted; LI-BMP site, LIPUS treatment was performed every three days after implantation of BMP-2; and Control site, neither implantation of BMP-2 nor LIPUS treatment was done.
At 3 weeks after surgery, thickness of new bone (TNB) was significantly higher in both the BMP and LI-BMP sites than in the Control site (P<0.05). TNB of every site in the 12w group was significantly higher than that of the same experimental site in the 70w group (P<0.05). Newly formed bone was almost integrated with original bone at the LI-BMP site.
These results suggest that LIPUS enhances the maturation of bone formation induced by BMP-2 even in senescent rats, although the volume of bone decreased with aging.