The Behavior Of New Hydrophilic Composite Bone Cements For Immediate Loading Of Dental Implant

Background and objectiveDental implant osseointegration finding known as the turning point of dental implant with immediate loading, in recent years due to shorten treatment time, aesthetics, and solve the problems such as anxiety, more and more attention. Implant loading success the most important precondition is the initial stability, has a good primary stability has laid a good foundation for the future progressive weight-bearing. According to traditional theory considering the volume and density of bone tissue, the width and length of the implant, usually require implants in3-6months after the implant function. The initial stability is one of the main causes of implant failure, overload other failure causes include infection, bone loss and biological mechanics. For the problem of early judgment will help to reduce the failure of implant, to alleviate the suffering of patients.Although the establishment of good primary stability of implant placed in when he was concerned, but it also has many other primary factors influencing implant. Therefore, from the beginning of bone absorption of preservation of peri-implant tissue is very important. However, the experimental study and clinical observation of the many problems still exist. Especially the immediate loading, bone tissue around the implant stability and maturity of the initial success is crucial to the long-term planting.This study adopts hydrophilic bone cement for the repair of bone defect between implant and bone tissue, improve the stability of the early planting material body, has obtained the good implant stability and higher implant maximum rotary torque. As everyone knows, bone cement as traditional materials a department of orthopedics and orthopaedics, long in the clinical application to hip replacement or centrum forming operation, get a good and long-term clinical efficacy, clinical in immediate implant often encountered in larger bone defects, implants of bone cement, hydrophilic after transformation can effectively filling the bone defect area, its high hydrophilic ability can be cross-linked structure between bone cement and bone tissue increased, the most important is the use of this implant can obtain very good primary stability, with larger rotation torque, provide a good foundation for the implant with immediate loading.In the first part of the experiment we will hydrophilic functional monomer was introduced to the traditional bone cement materials, to reconstruct the traditional bone cement material mechanical strength and hydrophilicity. hope to improve the traditional bone cement material hydrophilicity and high modulus of elasticity, and then use the MC3T3-E1cells were detected to observe the influence of characteristics of bone cement material of bone cells, and compared with each other.In the second part test we used fresh porcine mandibular premolars extraction area, teeth, bone cement of different groups into the socket, and inserted into the implant prefabricated, clean up excess bone cement material, wait for the bone cement is completely cured, use the special torque test instrument to measure the spin out the maximum torque of planting body required values. To obtain good experimental results, select a group of bone cement in the hydrophilic bone cement, adding the biodegradable material, poly lactic acid, through the preparation of5mm diameter circular bone defects in the rat skull, the bone cement filling bone defects respectively, were observed in the bone crosslinking. Hope to build long-term stability of the hydrophilic bone cement, is conducive to the dental implant long-term sustained loading, continue to produce preliminary exploration of crosslinking structure.Research methodsIn the first part of the experiment we use hydrophilic functional monomer acrylic acid, methyl methacrylate, divided into four groups:liquid1, methyl methacrylate monomer (MMA);2, methyl methacrylate monomer addition of20%(volume ratio) of2-hydroxyethyl methacrylate (HEMA); group3:methyl methacrylate the addition of20%acrylic acid monomer (AA); group4:methyl methacrylate monomer with10%hydroxyethyl methacrylate and acrylic acid (HEMA+AA)10%. Powder is spherical methyl methacrylate, diameter5um, average molecular weight of350000. Self purification two benzoyl peroxide prepared (BPO) and N, N-two methyl aniline (DMPT) constitute a redox system. The use of Teflon mold production standard work groups is needed specimen. Attenuated total reflection Fourier transform infrared spectroscopy to understand the changes of chemical bonds in the polymer materials, contact angle measuring instrument detection modified hydrophilic ability and wettability of bone cement. The specimen surface cultured osteoblast-like cells in bone cement with different composition (MC3T3-E1). For detection of cell adhesion and proliferation activity in bone cement surface with CCK-8kits; Luo Danming-phalloidin staining detection cell spreading and vitality.The second part of the experiment, four experimental groups have been used for immediate loading of dental implants, in the. The collection of fresh pig mandible, clear and soft tissue, using "minimally invasive" means premolar extraction area of the tooth socket, in filling bone cement, while inserting dental implants prefabricated, clean up excess bone cement, waiting for the torque testing instrument of bone cement is completely solidified using a dedicated, test spin out the maximum torque of planting body desired value. In order to build a sustainable, novel degradation can control the type of cement, selection of experimental group two bone cement on the basis of the above experiment (group20%HEMA), adding the biodegradable material, poly lactic acid. For the repair of bone defects of rats by skull5mm diameter circular bone defect area, further observation of bone crosslink formation, and record the results.The resultsThe three group of bone cement adding hydrophilic functional monomer by contact angle measurement system (OCA20) detection, has surface hydrophilicity improved, including20%acrylic acid (AA) surface hydrophilic group is the best, significantly better than the other three groups of bone cement.In the mechanical strength test, the hydrophilic into monomers makes traditional elastic modulus of acrylic bone cement has been reduced, this change is conducive to the implant and bone and cancellous bone is established between the elastic stress buffer zone, reduce the bite resultant stress generated in the implants, and caused bone resorption.Cytological test results show, a hydrophilic functional group did not change the traditional acrylic bone cement effects on bone cells, its security has not changed, further improvement of bone cement material beneficial effect on bone cells in the later test.By adjusting the torque testing can be informed, hydrophilic acrylic bone cement can greatly increase the primary stability of the implants, and obtain good rotation torque, the dental implant with immediate loading possible, further observation after loading effect in the future.