Recently, porous titanium granules (PTGs) have been indicated for the preservation of the dimensions of post-extraction sockets, as a filler in sinus lift procedures and for the treatment of peri-implant and periodontal defects, based on the osteoconductivity and dimensional stability of the titanium granules. However, there is a lack of information regarding the use of this material in larger defects and in conjunction with membranes. The objective of this study is to test the behavior of PTGs used to fill critical size defects in rabbit tibiae, with and without membranes. Critical defects were created in both tibiae of rabbits, divided randomly into three groups: Group A (defect filled with PTG), Group B (defect filled with PTG+collagen membrane) and a control group (empty defect). After six weeks, histomorphometric analysis was performed. The results showed more defect closures at the cortical area (87.37%±2.2%) and more bone formation at the marrow area (57.6%±1.3%) in Group B, in comparison with the other groups (P<0.05); the use of membranes improved the material stability expressed as more percentages of the original material when membranes were used (P<0.05). Finally, inflammatory reactions were observed when the granules were not protected by membranes. In spite of the limitations of this animal study, it may be concluded that PTG particles are osteoconductive and allow bone growth. The PTG particles must be covered by a membrane, especially when grafting larger defects, in order to control particle migration, promote clot stabilization and separate the PTG graft from undesired soft tissue cells.
Animals ; Male ; Membranes, Artificial ; Rabbits ; Tibia ; abnormalities ; Titanium ; chemistry

Aged ; Biological Monitoring ; Female ; Femur/chemistry* ; Humans ; Knee Joint/chemistry* ; Male ; Meniscus/chemistry* ; Metals/analysis* ; Middle Aged ; Tibia/chemistry*

OBJECTIVETo evaluate the effects a lithium chloride-doped calcium phosphate cement (Li/CPC) on promoting tibial defect repair in rats.

METHODSTwenty 6-month-old female SD rats randomized into Li/CPC (n=10) and CPC control (n=10) groups. Surgery was performed to create bone defects at the bilateral tibia, which were filled with either of the cement. Five rats from each group were sacrificed at 1 and 2 months after the surgery for micro-CT examination and HE staining of the tibia.

RESULTSMicro-CT showed better repair of bone defects in Li/CPC group, which had a significantly higher new bone volume fraction (BV/TV) and a lower trabecular separation/spacing (Tb.Sp) than the control group (P<0.05). HE staining showed an earlier appearance of fiber and osteoid callus in Li/CPC group than CPC control group. The number and quality of bone healing was significantly higher in Li/CPC group than in CPC group.

CONCLUSIONLi/CPC possessed better osteoinductivity and can significantly promote bone defect repair in rats.

Animals ; Bone Cements ; chemistry ; Calcium Phosphates ; chemistry ; Female ; Lithium ; chemistry ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tibia ; pathology

OBJECTIVETo study orientation remodeling without stress in bone harvest chamber.

METHODSThe bone harvest chamber (BHC) methodology is adopted in this study. Five female Japanese white rabbits were allowed unrestricted activity. The bone harvest chamber was a cylindrical Ti implant body with a transverse 1 mm wide canal for bone ingrowths. Retrieval of the contents of the canal was allowed with minimal disturbance to the surrounding bone or outer cylinder. After bone harvest chambers were implanted into the tibia of rabbits for 8 weeks, the chambers were considered to be osseointegrated with the bone. After harvested, the tissue were fixed and decalcified, then embedded in paraffin. Each rabbit was put into surgical operation 4 times for 4 stages: vacant for the first time; the tissue were cut into longitudinal sections at the second and third stages; harvesting tissues were cut into transverse sections at the fourth stage. Directional analysis: the standard deviation of the orientation of cell nucleus in each section was used as statistics, the difference between longitudinal section and transverse section were analyzed.

RESULTSOf the tissue into bone harvest chamber, directionality of cells arranged was more significantly on longitudinal section than on transverse section and there was statistical ignificecne.

CONCLUSIONUnder the no-stress circumstance of BHC bone remodeling showed directivity. Stress is not the direct leading signal about bone reconstitution. The structure of BHC might be related to orientation remodeling, which suggests that the relationship between orientation and stress is mediated by blood vessel. The effect of stress may be to affect vessel distributing in some orietation.

Animals ; Biomechanical Phenomena ; Cell Culture Techniques ; instrumentation ; methods ; Cells, Cultured ; Female ; Osteocytes ; chemistry ; cytology ; Rabbits ; Tibia ; chemistry ; cytology

By the bioactivity technology of Low-Temperature Preparation of Anatase and Rutile Layers on porous Titanium Substrates, CPTi(Commercially pure titanium Phi4.0 mm x 20 mm) was processed and treated as experiment specimens while CPTi was treated as control specimens. Experiment specimens and control specimens were implanted into the holes (4.0 mm in diameter) in rabbit's right and left tibias respectively. After implantation for predetermined periods of 4,8,12, 16 weeks, the specimens were taken out with bone tissues, and were examined by a press-out tester to evaluate the shearing force between the implant and the bone tissue. It is found that the shearing force between the experiment specimen and the bone is more significantly higher than that between the control specimen and the bone, and the bonding time is shorter, the stabilization time is faster. This study has laid down a good foundation for the titanium metal's innovative applications in clinical orthopaedics.
Animals ; Bone Substitutes ; chemistry ; Bone and Bones ; Cold Temperature ; Crystallization ; Materials Testing ; Orthopedic Fixation Devices ; Prostheses and Implants ; Rabbits ; Tibia ; Titanium ; chemistry

OBJECTIVETo compare the surface apposition and the bone response at early period of implantation in two differently treated implants.

METHODSThe implants were subject to double acid-etched-H2O2/HCl-heat treatment and double acid-etching treatment, and then randomly implanted into the tibia of rabbits. After 2, 4, 8 weeks of follow up, the bone specimens containing implants were prepared and examined by a field emission SEM and EDX.

RESULTA layer rich with calcium and phosphorus was clearly demonstrated on the implants surface of both groups after 2 weeks of implantation, but it was mostly disappeared after 4 weeks. There were large amounts of osteoblasts cells on double acid-etched-H2O2/HCl-heat treated implants surface indicating the initiation of osteogenesis. After 8 weeks of implantation some new bones were attached on the implants surface in both groups, more bones attached were shown on double acid-etched- H2O2/HCl-heat treated implants surface.

CONCLUSIONA calcium and phosphorus-rich layer was formed on the implants surface of both groups at early period of implantation.

Animals ; Dental Implantation ; Dental Implants ; Dental Materials ; chemistry ; Dental Prosthesis Design ; Hydrogen Peroxide ; chemistry ; Osseointegration ; physiology ; Osteogenesis ; physiology ; Rabbits ; Surface Properties ; Tibia ; surgery ; ultrastructure ; Titanium ; chemistry

BACKGROUNDBone grafting is commonly used to repair bone defects. As the porosity of the graft scaffold increases, bone formation increases, but the strength decreases. Early attempts to engineer materials were not able to resolve this problem. In recent years, nanomaterials have demonstrated the unique ability to improve the material strength and toughness while stimulating new bone formation. In our previous studies, we synthesized a nano-scale material by reinforcing a porous β-tricalcium phosphate (β-TCP) ceramic scaffold with Na2O-MgO-P2O5-CaO bioglass (β-TCP/BG). However, the in vivo effects of the β-TCP/BG scaffold on bone repair remain unknown.

METHODSWe investigated the efficacy of β-TCP/BG scaffolds compared to autografts in a canine tibiofibula defect model. The tibiofibula defects were created in the right legs of 12 dogs, which were randomly assigned to either the scaffold group or the autograft group (six dogs per group). Radiographic evaluation was performed at 0, 4, 8, and 12 weeks post-surgery. The involved tibias were extracted at 12 weeks and were tested to failure via a three-point bending. After the biomechanical analysis, specimens were subsequently processed for scanning electron microscopy analysis and histological evaluations.

RESULTSRadiographic evaluation at 12 weeks post-operation revealed many newly formed osseous calluses and bony unions in both groups. Both the maximum force and break force in the scaffold group (n = 6) were comparable to those in the autograft group (n = 6, P > 0.05), suggesting that the tissue-engineered bone repair achieved similar biomechanical properties to autograft bone repair. At 12 weeks post-operation, obvious new bone and blood vessel formations were observed in the artificial bone of the experimental group.

CONCLUSIONSThe results demonstrated that new bone formation and high bone strength were achieved in the β-TCP/BG scaffold group, and suggested that the β-TCP/BG scaffold could be used as a synthetic alternative to autografts for the repair of bone defects.

Animals ; Autografts ; Bone Substitutes ; chemistry ; Ceramics ; Dogs ; Female ; Fibula ; injuries ; surgery ; Hydroxyapatites ; chemistry ; Tibia ; injuries ; surgery ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry

PURPOSE: The aim of this study was to investigate the combined effects of physical and chemical surface factors on in vivo bone responses by comparing chemically modified hydrophilic sandblasted, large-grit, acid-etched (modSLA) and anodically oxidized hydrophobic implant surfaces. METHODS: Five modSLA implants and five anodized implants were inserted into the tibiae of five New Zealand white rabbits (one implant for each tibia). The characteristics of each surface were determined using field emission scanning electron microscopy, energy dispersive spectroscopy, and confocal laser scanning microscopy before the installation. The experimental animals were sacrificed after 1 week of healing and histologic slides were prepared from the implant-tibial bone blocks removed from the animals. Histomorphometric analyses were performed on the light microscopic images, and bone-to-implant contact (BIC) and bone area (BA) ratios were measured. Nonparametric comparison tests were applied to find any significant differences (P<0.05) between the modSLA and anodized surfaces. RESULTS: The roughness of the anodized surface was 1.22 +/- 0.17 microm in Sa, which was within the optimal range of 1.0-2.0 microm for a bone response. The modSLA surface was significantly rougher at 2.53 +/- 0.07 microm in Sa. However, the modSLA implant had significantly higher BIC than the anodized implant (P=0.02). Furthermore, BA ratios did not significantly differ between the two implants, although the anodized implant had a higher mean value of BA (P>0.05). CONCLUSIONS: Within the limitations of this study, the hydrophilicity of the modSLA surface may have a stronger effect on in vivo bone healing than optimal surface roughness and surface chemistry of the anodized surface.
Animal Experimentation ; Animals ; Chemistry ; Dental Implants ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Osseointegration ; Rabbits ; Spectrum Analysis ; Tibia ; Titanium*

OBJECTIVETo investigate the mechanical characteristics of new anatomic plate of distal tibia from view of biomechanics.

METHODSTwelve fresh adult moist ankle specimens were randomly divided into four block groups (every group had 3 specimens), 3 tibial specimens as a normal control (normal group N), 9 specimens were resulted in unstable distal tibial Pilon fracture. Using steel plate fixation with a new anatomic distal tibial plate (group A), reconstruction plate (group B), clover plate (group C). Group B and group C as control group to test the remote axial compressive strength, remote axial stiffness, reversing biomechanical properties, contacted characteristics of the tibial astragaloid articular surface.

RESULTSThe remote axial compressive strength, remote axial stiffness, reversing biomechanical properties, contacted characteristics of tibial astragaloid articular surface the in distal tibial Pilon fracture instability of group A were near normal group N (P>0.05). Group A was best than group B and C (P<0.05).

CONCLUSIONThe new anatomic plate of distal tibia was relatively strong, which can reach effective and stable fixation for unstable distal tibial Pilon fracture.

Biomechanical Phenomena ; Bone Plates ; Fracture Fixation, Internal ; Humans ; In Vitro Techniques ; Tibia ; chemistry ; injuries ; surgery ; Tibial Fractures ; surgery

OBJECTIVETo explore the role of preoperative calcaneal traction in the treatment of Rüedi-Allgöwer II and III Pilon fracture.

METHODSFrom March 2005 to March 2010, 56 patients with Rüedi-Allgöwer II and III Pilon fracture were treated by calcaneal traction internal fixation on the second phase. There were 42 males and 14 females with an average age of 34.6 years old (ranged 18 to 68). Clinical outcomes were assessed according to Tormette Pilon and tibia fracture standard.

RESULTSAll patients were followed up from 9 to 36 months with an average of 18 months. All fracture obtained bone healing, the time ranged from 4.5 to 8.2 months with a mean of 6.2 months. No deep infection, breakage of internal fixation and other complications occurred. According to Tornetta evaluation criteria,35 cases got excellent results, 18 cases good,and 3 cases fair.

CONCLUSIONPreoperative calcaneal traction as a temporary fixing measure can provide a good environment for successful operation, and is an essential foundation for recovering functional, painless, load, movable joint.

Adolescent ; Adult ; Aged ; Calcaneus ; chemistry ; surgery ; Female ; Fracture Fixation, Internal ; Humans ; Male ; Middle Aged ; Preoperative Period ; Tibia ; chemistry ; surgery ; Tibial Fractures ; surgery ; Traction ; Young Adult