Microarc oxidation (MAO) has become a promising technique for the surface modification of implants. Therefore, the aims of this study were to further quantitatively and qualitatively evaluate the osteointegration abilities of MAO-treated and smooth surface (SF) implants in vivo and to investigate the areas in which the superiority of MAO-treated implants are displayed. In a rabbit model, a comprehensive histomorphological, osteogenic, mineralizational, and integrative assessment was performed using light microscopy, fluorescence microscopy, confocal laser scanning microscopy, and radiographic analyses. Compared with the SF groups, the MAO-treated groups exhibited more active contact osteogenesis, as well as distant osteogenesis, under fluorescence examination, the mineral apposition rate was found to be greater for all of the MAO-treated implants, and the osteointegration index (OI) value was greater in the MAO-treated groups at different times. In conclusion, the calcium-rich amorphous layer created by MAO provided a better environment for osteointegration, with more active contact osteogenesis, a more rapid mineral apposition rate and greater OI values.
Animals ; Bone-Implant Interface ; physiology ; Dental Implantation, Endosseous ; methods ; Dental Implants ; Femur ; surgery ; Implants, Experimental ; Materials Testing ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Models, Animal ; Osseointegration ; physiology ; Oxidation-Reduction ; Rabbits ; Spectrometry, X-Ray Emission ; Surface Properties ; Titanium

Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium (Ti), titanium-zirconium (TiZr) alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.
Acid Etching, Dental ; methods ; Alloys ; chemistry ; Bacterial Adhesion ; physiology ; Bacteriological Techniques ; Biofilms ; Cell Adhesion ; physiology ; Cell Culture Techniques ; Cell Line, Tumor ; Cell Movement ; physiology ; Ceramics ; chemistry ; Coculture Techniques ; Dental Alloys ; chemistry ; Dental Etching ; methods ; Dental Implants ; microbiology ; Dental Materials ; chemistry ; Dental Polishing ; methods ; Humans ; Osseointegration ; physiology ; Osteoblasts ; physiology ; Porphyromonas gingivalis ; physiology ; Prevotella intermedia ; physiology ; Surface Properties ; Titanium ; chemistry ; Yttrium ; chemistry ; Zirconium ; chemistry

Animals ; Biomechanical Phenomena ; Bone Density ; Dental Alloys ; chemistry ; Dental Implants ; Dental Prosthesis Design ; Dental Restoration Failure ; Esthetics, Dental ; Humans ; Osseointegration ; physiology ; Torque ; Zirconium ; chemistry

This paper is aimed to assess the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2) and bone marrow stromal cell (BMSCs) composited tricalcium phosphate (TCP) in a rat model of posterolateral lumbar intertransverse process fusion. Rat BMSCs were cultured in vitro. Twenty SD rats underwent single-level bilateral intertransverse process spine arthrodesis at L4 and L5. These rats were assigned to two groups according to the graft materials. They received: 10 of the total were treated with the BMSCs with rhBMP-2 and tricalcium phosphate (TCP) as the experimental group, and the other 10 with TCP treatment alone as the control group. All the animals were killed at 4 weeks after surgery and the spine fusion results were assessed by gross inspection, manual palpation, radiography and histology. The fusion rate, the tensile strength and stiffness of the solidly fused levels in the experimental group were statistically higher than that of the controlled group (P < 0.05). These results showed that the spinal fusion could be improved mechanically when rhBMP-2 and BMSCs were added into the TCP.
Animals ; Bone Morphogenetic Protein 2 ; therapeutic use ; Calcium Phosphates ; therapeutic use ; Cells, Cultured ; Combined Modality Therapy ; Female ; Lumbar Vertebrae ; surgery ; Male ; Mesenchymal Stem Cell Transplantation ; methods ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Osseointegration ; physiology ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; therapeutic use ; Spinal Fusion ; methods ; Transforming Growth Factor beta ; therapeutic use

Strontium added into porous hydroxyaptite ceramics has the functions of improving its osseointegration, decreasing its dissolution rate and improving the bone density. Strontium-containing hydroxyaptite (Sr-HA) ceramics has been used as bone replacement and scaffold to treat the osteoporosis and bone default in clinic, but the mechanism of interfacial tissue response caused by the trace element Sr in Sr-HA ceramics still remains to be further studied. Four types of Sr-HA ceramic samples with different contents of Sr were prepared by microwave plasma sintering for testing the response of the soft tissue implanted in dog muscles in our laboratory. The contents of Sr element in the samples are 0 mol%, 1 mol%, 5 mol%, and 7 mol%, respectively. The samples were implanted in the muscle of the dogs for 4 weeks, 8 weeks and 12 weeks, respectively. The histological observations at the end of each period showed that the irritant ranking increased with the content of Sr in Sr-HA ceramics at the end of 12 weeks, and there were rich bone tissue in Sr-HA ceramic samples with 5 mol% Sr element. The overdose of element Sr is harmful to soft tissues. When the content of Sr in Sr-HA ceramic was below 5 mol%, the soft tissue response was very slight and the new bones were induced to grow well.
Animals ; Bone Substitutes ; chemical synthesis ; Ceramics ; chemical synthesis ; chemistry ; Dogs ; Durapatite ; chemical synthesis ; chemistry ; Female ; Male ; Muscle, Skeletal ; surgery ; Osseointegration ; physiology ; Porosity ; Prostheses and Implants ; Strontium ; chemistry ; Tissue Engineering

Micromotion and fretting damages at the dental implant/bone interface are neglected for the limitation of check methods, but it is particularly important for the initial success of osseointegration and the life time of dental implant. This review article describes the scientific documentation of micromotion and fretting damages on the dental implant/bone interface. The fretting amplitude is less than 30 µm in vitro and the damage in the interface is acceptable. While in vivo, the micromotion's effect is the combination of damage in tissue level and the real biological reaction.
Biomechanical Phenomena ; Bone and Bones ; anatomy & histology ; physiology ; Dental Implants ; Humans ; Mechanical Phenomena ; Movement ; Osseointegration ; physiology ; Stress, Mechanical ; Surface Properties

OBJECTIVETo assess the osseointegration capability of hydroxyapatite-coated porous titanium with bone morphogenetic protein-2 (BMP-2) and hyaluronic acid to repair defects in the distal femur metaphysis in rabbits.

METHODSPorous titanium implants were made by sintering titanium powder at high temperature, which were coated with hydroxyapatite by alkali and heat treatment and with BMP-2 combined with bone regeneration materials. And hyaluronic acid was further used as delivery system to prolong the effect of BMP-2. The implants were inserted into the metaphysis of the distal femur of rabbits. The animals were killed at 6, 12 and 24 weeks to accomplish histological and biomechanical analyses.

RESULTSAccording to the result of histological analysis, the osseointegration in BMP-2 group was better than that of the HA-coated porous titanium group. In push-out test, all the samples had bigger shear stress as time passed by. There was statistical difference between the two groups in 6 and 12 weeks but not in 24 weeks.

CONCLUSIONHydroxyapatite-coated porous titanium with BMP-2 and hyaluronic acid has a good effect in repairing defects of distal femur in rabbits, which is a fine biotechnology for future clinical application.

Animals ; Biomechanical Phenomena ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; pharmacology ; Coated Materials, Biocompatible ; Durapatite ; Femur ; surgery ; Hyaluronic Acid ; pharmacology ; Osseointegration ; physiology ; Porosity ; Prostheses and Implants ; Rabbits ; Titanium ; Transforming Growth Factor beta ; pharmacology

Using the CT data, we have constructed the finite element models of human femur distally amputated at high-position, middle-position and low-position, along with distally osseointegrated implant under the maximal load during a normal walking cycle. Results of finite element analysis revealed: the maximal stress of implant is produced near the exit of the amputated limb, where the fatigue breakpoint caused by cyclic stress would take place. With the ascending of truncated position, the peri-implant interfacial stress of bone increases. There is severe stress-shielding at the bone-implant interface, and there is concentration of stress at the end of implant and at the 3/4 point of femur, which would lead to bone loss and bone resorption and would shorten the longevity of implant. The results also showed that the curvature of natural bone has notable effect on the stress distribution, which should not be neglected. These data may provide reliable reference for the design and research of osseointegarted artificial limb.
Artificial Limbs ; Computer Simulation ; Femur ; physiology ; Finite Element Analysis ; Humans ; Imaging, Three-Dimensional ; Models, Biological ; Osseointegration ; physiology ; Prosthesis Design ; Stress, Mechanical

OBJECTIVETo evaluate the stability of mini-screw implant during different healing periods in the unloaded conditions.

METHODSSixty titanium mini-screws were used in this study. A total of 10 New Zealand white rabbits were randomly divided into 5 groups according to different healing periods. The stability was evaluated biomechanically at different time points. One-way ANOVA and correlation analyses were used.

RESULTS(1) After 4 weeks and 8 weeks of healing, maximal pull-out loads were (179.68 +/- 24.65) N and (212.06 +/- 42.51) N, respectively. The maximal torques were (0.47 +/- 0.13) N.m and (0.61 +/- 0.16) N.m, respectively. (2) Significant difference in maximal torque was found between 4 week and 8 week healing groups. (3) Both reverse torque and pull-out load significantly correlated with healing time.

CONCLUSIONSFourth-week is a critical time point in the progress of osseointegration. Within 8 weeks of healing process, the stability of implant was significantly correlated with healing time.

Animals ; Bone Screws ; Dental Implantation, Endosseous ; Dental Implants ; Dental Stress Analysis ; Male ; Orthodontic Anchorage Procedures ; Osseointegration ; physiology ; Rabbits ; Stress, Mechanical ; Time Factors ; Titanium ; Torque ; Wound Healing ; physiology

OBJECTIVETo evaluate the combination of surgical grade calcium sulfate hemihydrate (SGCS) and platelet-rich plasma (PRP) for alveolar ridge preservation prior to implant placement.

METHODSChanges of bone quantity and quality in extraction sites following the SGCS/PRP and SGCS implantations were investigated by spiral computer tomography scan, bone scintigraphy, radiographic, histological and histomorphometric examinations.

RESULTSThe placement of SGCS/PRP reduced the resorption of the alveolar ridge. It also promoted bone metabolism and bone-to-implant contact. The addition of PRP to SGCS achieved the enhancement of the bone metabolism only at the early healing phase.

CONCLUSIONSIn this animal experiment, SGCS/PRP may be used as fresh extraction sockets graft for alveolar ridge preservation prior to implant placement.

Alveolar Bone Loss ; prevention & control ; Alveolar Process ; pathology ; surgery ; Animals ; Bone Substitutes ; therapeutic use ; Calcium Sulfate ; therapeutic use ; Dental Implants ; Dogs ; Male ; Mandible ; pathology ; surgery ; Osseointegration ; physiology ; Osteogenesis ; physiology ; Platelet-Rich Plasma ; Radiopharmaceuticals ; Tomography, X-Ray Computed