Evaluation of 4 different bone graft substitutes and autogenous bone grafting in root-end resection osteotomies after retrograde root-filling with Intermediate Restorative Material(IRM):An experimental study in dogs

Purpose: To investigate the periapical tissue response after root end filling with intermediate restorative material (IRM) and filling of the root-end resection bone defects with autogenous bone or a bone graft substitute in comparison to empty controls. Materials and Methods: Vital roots of the second, third and fourth mandibular premolars in six healthy mongrel dogs were apectomized. The root canals were prepared and sealed with IRM following a standardized surgical procedure. The resection bone defects were either filled with autogenous bone (PB) or one of the bone graft substitutes;CERAMENTTM|BONE VOID FILLER, ChronOS?, TigranTM PTG, Easygraft? CLASSIC or left empty. After 120 days the animals were sacrificed and the specimens were analyzed radiologically and histologically. Kruskal-Wallis and Mann-Whitney tests were performed for statistical evaluation. Results: 34 sections were analyzed histologically. The evaluation revealed a variation in the outcome amongst the tested options, regarding reestablishment of the periapical bone healing and inflammatory infiltration in the sections. According to the tested variables, there was no statistical significant difference between the materials when comparing all groups as a whole. When comparing individual materials to each other there was statistical differences among some of the tested materials. Conclusion: The healing outcome after periapical surgery of a five-wall resection defect could not be increased by infill with autogenous bone or bone graft substitutes. The most important factor for the healing outcome in periapical surgery is the quality of the root-end sealing. The healing outcome after some of the tested bone substitutes, might be improved by longer healing time.

A comparative study of autogenous, allograft and artificial bone substitutes on bone regeneration and immunotoxicity in rat femur defect model

Repair and reconstruction of large bone defect were often difficult,and bone substitute materials,including autogenous bone,allogenic bone and artificial bone,were common treatment strategies.The key to elucidate the clinical effect of these bone repair materials was to study their osteogenic capacity and immunotoxicological compatibility.In this paper,the mechanical properties,micro-CT imaging analysis,digital image analysis and histological slice analysis of the three bone grafts were investigated and compared after different time points of implantation in rat femur defect model.Autogenous bone and biphasic calcium phosphate particular artificial bone containing 61.4% HA and 38.6%β-tricalcium phosphate with 61.64%porosity and 0.8617±0.0068 g/cm^(3) den-sity(d≤2 mm)had similar and strong bone repair ability,but autogenous bone implant materials caused greater secondary damage to experimental animals;allogenic bone exhibited poor bone defect repair ability.At the early stage of implantation,the immunological indexes such as Immunoglobulin G,Immunoglobulin M concentration and CD4 cells'population of allogenic bone significantly increased in compared with those of autologous bone and artificial bone.Although the repair process of artificial bone was relatively inefficient than autologous bone graft,the low immunotoxicological indexes and acceptable therapeutic effects endowed it as an excellent alter-native material to solve the problems with insufficient source and secondary trauma of autogenous bone.

Clinical observation of mineralized collagen bone grafting after curettage of benign bone tumors

Curettage of benign bone tumor is a common cause for bone defect.For such bone defect repair,autogenous bone,allogeneic bone and traditional artificial bone graft substitutes have many disadvantages.In recent years,a biomimetic mineralized collagen(MC)with similar composition and microstructures to the natural bone matrix was developed and used for treating various bone defects.In this work,a retrospective study analyzed clinical outcomes of patients treated with curettage of benign bone tumors and bone grafting with MC,in comparison to another group treated with the same surgical method and autogenous bone.Lane-Sandhu X-ray score of the autogenous bone group was superior to the MC group at 1 month after the operation,but the two groups had no statistical difference at 6 and 12 months.The MC group was better in Musculoskeletal Tumor Society scoring at 1 and 6 months after the operation,and the two groups had no statistical difference at 12 month.Therefore,the MC performed not as good as autogenous bone in early stage of bone healing but achieved comparable outcomes in long-term follow-ups.Moreover,the MC has advantages in function recovery and avoided potential complications induced by harvesting autogenous bone.

Effect of morselized bones on binding of the canine hydroxyapatite-coated femoral stem

Background Non-cement femoral stems are recognized in clinical use, but there are still some problems. The aim of this research was to make non-cement femoral stems to be press-fit with the medullary cavity. Methods Twenty-four healthy adult mongrel dogs were randomly divided into experimental and control groups. In the right hip joint, an artificial femoral bone replacement surgery was conducted. For the experimental group, the replacement surgery of hydroxyapatite （HA）-coated femoral stems was done, while autogeneous morselized bone was implanted into the medullary cavity. For the control group, morselized bone was not implanted. At postoperative 1, 3, 6 months, a test for interfacial shear characteristics was conducted in the MTS810 Tester. The comparison between the two groups＇ bone-prostheses in shear strength for their interface from shearing destruction was made. A histological observation to check prosthesis-bone interface contact ratios and bone growth was carried out. Results For the experimental group, shear strength was 0.317 MPa in 1 month, 1.447 MPa in 3 months, and 1.621 MPa in 6 months. For the control group, shear strength was 0.195 MPa in 1 month, 1.023 MPa in 3 months, and 1.483 MPa in 6 months. The difference was statistically significant. Stereomicroscope-based observation showed that the number of trabecular bones in the experimental group was larger than that of the control group, and bone growth of the former group was better than that of the latter group. Inverted microscopic observation showed that the binding degree between the prosthesis and trabecular bone of the experimental group was higher than that of the control group. Comparatively, the experimental group＇s trabecular bone had more stromal cells. Conclusions The morselized bones can effectively improve the biological bonding strength and bone-contact ratios in the short term for the HA-coated femoral stem and accelerate the bonding process. The use of morselized autogenous bones played a good role in bone in-growth of the femoral bone stem surface.