Search

Background: Guided bone regeneration (GBR) involves collecting bone autografts with high bio-quality and efficiency. The current non-irrigated low-speed drilling has been limited for broader application in bone autograft harvest due to its low efficiency, inability to conduct buccal cortical perforation, and dependence on simultaneous implant placement. Increasing the drilling speed helps improve the efficiency but may incur thermal-mechanical bone damage. Most studies have addressed thermal reactions during bone drilling on non-vital models, which is irrelevant to clinical scenarios. Little has been known about bone's in vivo thermal profiles under non-irrigated higher-speed drilling and its influences on the resulting bone chips. Aim: A novel technique for bone harvest and cortical perforation via in-situ non-irrigated higher-speed drilling was proposed and investigated for the first time. Methods: The third mandible premolars of eight beagles were extracted and healed for three months. Sixteen partial edentulous sites (left and right) were randomized into four groups for bone autograft harvest without irrigation: chisel, 50 rpm drilling, 500 rpm drilling, and 1000 rpm drilling. Bone chips were harvested on the buccal plates of the missing tooth. An infrared camera and an implantable thermocouple collaboratively monitored in vivo real-time bone temperature at the drilling sites. In vitro performances of cells from bone chips, including cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, mRNA transcriptional level of osteogenic genes and heat shock protein 70 (HSP-70), and HSP-70 expression at the protein level were also studied. Results: 500 rpm produced mild local hyperthermia with a 2–6 °C temperature rise both on the cortical surface and inside the cortical bone. It also held comparable or enhanced cell performances such as cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, and osteogenic genes expression. Conclusions: In-situ non-irrigated higher-speed drilling at 500 rpm using a screw drill is versatile, efficient, and thermal friendly and improves the bio-quality of bone chips. Our novel technique holds clinical translational potential in GBR application. [ABSTRACT FROM AUTHOR]

In the case of instrumental spine fusion with the achieved biomechanical rigidity of the operated segment, the use of plateletrich fibrin to stimulate osteogenesis is promising. Objective: to study the possibility of lumbar spine fusion under conditions of platelet-rich fibrin usage in the experiment. Methods: fusion modeling was made in 42 mature male Californian rabbits, which were divided into 6 groups of 7 individuals in each group In the 1st group we did not use g rafts (control g roup); in the 2nd group we used bone autografts; in the 3rd -- b one autografts with platelet-rich fibrin; in the 4th -- allografts from iliac crest; in the 5th -- a llografts f rom i liac c rest c ombined with platelet-rich fibrin; in the 6th -- platelet-rich fibrin. Methods: roentgenological, morphological, statistical. Results: false positive fusion was revealed on X-rays in the 1st group in 28.6% of cases, in the group 6th -- in 7.1%, false negative -- in the 2nd and t he 3rd groups -- equal in 7.1%. In the control group 1st spine fusion was not found. In all other groups we have found the callous formation with different amount of bone, cartilage and connective tissue. In these groups on radiographs, the optical density of the newly formed bone exceeded the same parameters of the cancellous bone of the adjacent vertebral bodies. Conclusions: the greatest osteogenic properties were found in the case of a combination of bone autografts with platelet-rich fibrin: the highest incidence of fusion (71.4%) was recorded, in which the predominantly mature bone tissue was formed. Regardless of the type of the graft (auto- or allo-), platelet-rich fibrin increased its reparative capabilities, providing a higher frequency of bone marrow formation based on the results of radiography a nd h istology. [ABSTRACT FROM AUTHOR]