| Tooth defects caused by caries,trauma,and abnormal tooth development are common and frequent diseases in oral clinics.With the increase in the degree of tooth defect,the restoration methods changed from filling treatment,inlay restoration,and then full crown restoration.When the remaining crown tissue continued to decrease and could not provide direct retainer and support for the whole crown,and the root of tooth condition was good,the post-core crown became the main restoration method.The service life of the post-core crown varies greatly,and the failure of post and core crown repair mainly includes two forms: post-core detachment or root fracture.The metal and ceramic post-core materials used at present with good mechanical strength and were not easy to break,but they were easy to cause root fracture due to their large elastic modulus.The prefabricated fiber post material with a small elastic modulus broke ahead of the root when the bite force was large,which could better protect the root.However,the prefabricated fiber post had a high requirement on the residual amount of the teeth and had poor cohesion with the root canal dentin,which was prone to debonding.Because of the above clinical problems,this job intended to develop a new composite polymer material for personalized post-core fabrication.Polyether ether ketone（PEEK）had excellent biocompatibility,good mechanical properties,high-temperature resistance,chemical stability,polishing,wear resistance,the low affinity of plaque,X-ray transmission,magnetic resonance compatibility,and other characteristics.The elastic modulus of PEEK material was lower than that of metal and ceramic materials and close to the human skeleton.It had excellent machinability and can be adjusted by material blending,surface modification,and other methods to meet the clinical requirements of various prostheses.This job intended to design and prepare to PEEK with different contents of Glass Fiber（GF）,the composites were tested for mechanical properties,biological safety,and bonding properties.It intended to develop new polymer composite materials for oral post-core,to broaden the oral clinical application of PEEK material.Objective:The purpose of this job is to design and develop a new type of PEEK composites so that it has the basic properties of oral post-core material.Methods:1、 PEEK-GF composite materials with different contents of glass fiber（0%,30%,40%,and 50%）were prepared by extrusion injection,and they were named PEEK group,PEEK-GF30 group,PEEK-GF40 group,and PEEK-GF50 group respectively.The mechanical properties such as bending modulus,bending strength,Vickers hardness,and compression strength were tested.Then the section morphology was observed by scanning electron microscopy（SEM）.2、 In vitro CCK-8 was used to detect the cytotoxicity of the composites,and the cell morphology was observed under a microscope.DAPI staining was used to observe the cell growth on the surface of the composites.3、 PEEK-GF50 composites with different surface treatment,respectively are no treatment group,sandblasting group,plasma group,sandblasting and plasma group.The bonding shear strength（SBS）of each group before and after the cycle was tested,the failure mode was observed,and the contact angle after different treatments was tested.The surface morphology of different treatments was observed by scanning electron microscope（SEM）.Results:1、The mechanical properties of PEEK composites improved with the increase of GF contents.In the PEEK-GF50 group,the elastic modulus reached 17.4± 0.49 GPa,which was very close to dentin（18.6 GPa）,and the bending strength was 350± 2.88 MPa,and the Vickers hardness was 47.62± 4.54 HV.The compressive strength was264± 18.01 MPa;SEM analysis showed that the glass fiber was well combined with the PEEK matrix.2、CCK-8 results showed that the composites in each group had good biosafety,and the cell morphology was normal under the microscope.DAPI staining showed no significant difference in the number of cells on the composites compared with the control group.3、 After sandblasting and plasma pretreatment,PEEK-GF50 achieved the highest SBS（16.02±1.73 MPa）,which could still reach（11.7±0.56 MPa）after 5000 thermal cycles The contact angle of this group was the smallest,39.2 ± 5.9 °;There was significant statistical difference compared with other groups（P<0.01）.Scanning electron microscopy showed that many protrusions were formed on the surface,which was rougher than that in the untreated group.Conclusion:By analyzing the experimental results,it can be concluded that the PEEK-GF50 composites formed by extrusion and injection molding had mechanical properties similar to dentin,good biosafety,and shearing bonding strength that can meet clinical requirements.So it was a new type of oral post-core material with good application prospects. |
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