The Study Of Attrition Property About Three Kinds Of Crown Restoration Materials With Enamel And Dentin

Background:With the development of the prosthodontic materials,the requirement of the materials is higher and higher.The attrition property of the material is a standard to judge whether the material is good or bad.Excessive attrition caused by materials on occlusal teeth may cause tooth sensitivity,occlusal disorder,temporomandibular joint disease and other problems.At present,zirconia all-ceramic,lithium disilicate ceramics and titanium are widely used in crown and inset repair.Therefore,it is necessary to consider the attrition of the above materials on enamel and dentin in clinical practice.In this experiment,the attrition properties of zirconia all-ceramic,lithium disilicate ceramics and titanium materials were compared using an in vitro experimental machine to compare the differences in the attrition properties of the three materials.Objective:The hardness of titanium restorative material of zirconia^ lithium disilicate ceramics and that of natural enamel dentin were compared and the volume loss between them and talc porcelain before and after attrition were calculated.Methods:Vertical universal friction and wear testing machine was used.The test group was zirconia all-ceramic,lithium disilicate ceramics and titanium,the control group was natural enamel and dentin.The experimental group and the control group were respectively installed in the upper fixture of the attrition machine.The talc specimens were installed in the lower part of the test machine,and the pressure loading attrition test was carried out in the artificial saliva environment.The volume loss of upper and lower specimens before and after wear is calculated.The attrition pattern of each specimen after the experiment was observed under SEM,vickers hardness tester was used to test the hardness of the above specimens.Results:1.Scanning electron microscopy results:the enamel and dentin surfaces were uneven,with obvious scratches and deep furrows.The surfaces of zirconia all-ceramic,lithium disilicate ceramics and titanium have relatively flat surfaces compared with enamel and dentin,all of which have scratch structures but are not obvious,and the structures of the three materials themselves are quite different from enamel and dentin.Among them,the attrition modes of enamel and dentin are mainly abrasive attrition,adhesive attrition and fatigue attrition,while zirconia all-ceramic,lithium disilicate ceramics and titanium are mainly abrasive attrition.2.Hardness test results:the specimen hardness values(MPa)from big to small respectively:zirconium oxide(992.14±8.74),lithium disilicate(388.37±5.25),titanium(243.26±4.65),enamel(352.14±3.72),and dentin(60.21±1.26),th e enamel similar to the lithium silicate hardness(P>0.05),and hardness are di fferent between groups,statistical differences(P<0.05).3.Volume loss(mm3):?the volume loss of dentin was the largest(10.245810.8469),which was statistically different from other groups(P<0.05).There was no significant difference between the volume loss of enamel(6.5426±0.4225)and lithium disilicate(6.7964±0.4638),titanium(6.3951±0.5365),and zirconia(1.2968±0.2654)(P<0.05).?the talc porcelain volume loss:dentin group(4.9784±0.8967)with other were statistical differences between groups(P<0.05),the enamel group(6.9863±0.6624)with lithium disilicate ceramic group(6.9092±0.5142),titanium(6.2413±0.5427)between the volume loss has no statistical significance(P>0.05),enamel and zirconium oxide group(9.6437±0.9431)between the volume loss has statistical differences(P<0.05).?analysis of the volume loss of specimens and talc porcelain:there were statistical differences between the volume loss of enamel,dentin,lithium disilicate and zirconia and the corresponding talc porcelain respectively(P<0.05),while there was no statistical difference between the volume loss of titanium and talc porcelain(P>0.05).Conclusion:1:Zirconia has the strongest attrition performance,which is easy to cause excessive attrition to enamel;The attrition property of lithium disilicate,titanium and enamel are similar,and it is not easy to cause excessive attrition to enamel.2:Zirconia,lithium disilicate,titanium are easy to cause excessive attrition to dentin.3:The attrition performance of the material is positively correlated with the hardness value.The higher the hardness is,the stronger the attrition performance will be.