Study on Optical Property of4Kinds of All-ceramic Core Materials
|Keywords||Dental materials Core porcelain Transmittance Translucency Background color|
Modern dental ceramics break through the bottle of low-strength andhigh-fragility of traditional ceramics,and they have widely applied in prostheticsfield.An increasing number of demand for the simulatability of prosthesis,theaesthetic effect of dental all-ceramic materials have gradually become the researchhotspot.Good translucency and vivid color are the important index for evaluatingthe quality of all-ceramic prosthesis.Bilayered composite structure is widelyadopted by dental all-ceramic restorations,which consist of core material withhigh-strength being as supporter and veneering porcelain for restoring the shapeand color of natural tooth.Being better translucency,veneering porcelain couldpreferably simulate the aesthetic effect of natural tooth,While good transparencyof core material would make prosthesis more vivid and texture.Owing to havingdifferent crystal content and crystal property,all-ceramic core materials appearsignificantly different translucency. Therefore,good translucency of core materialis an essential factor for prosthesis to reappear natural tooth’s color and a criticalconsideration in the selection of materials.Besids,because of its translucency, thefinal aesthetic effect of all-ceramic prosthesis easily affected by backgroundcolor,and it would vary according to different post-core materials.This studyanalyse the optical property of4kinds of all-ceramic core materials,includingdetermination spectral transmittance,determination translucency before and afterveneering porcelain,and discuss the influence of different post-core materials onthe color of all-ceramic materials. Results show as follows:1.At clinically recommended thickness,the spectral transmittance of4kinds ofall-ceramic core materials are IPS e.max6.113%～6.750%, Lava Zirconia1.604%～2.135%,Zenostar1.578%～2.117%and upceraZirconia0.995%～ 1.265%.Their relative translucency have significant difference,which are adecreasing order, IPS e.max Press＞Lava Zirconia＞Zenostar＞upceraZirconia.2.After veneered(veneering porcelain being at clinically recommendedthickness),the relative translucency of4kinds of all-ceramic core materials aresignificantly different.The order of relative translucency from high to lowis,Vitadur Alpha dentin(as control)＞IPS e.max Press＞LavaZirconia＞Zenostar＞upceraZirconia.IPS e.max Press with good optical effect may be preferable forrestoring higher translucent anterior tooth;Lava Zirconia and Zenostar withcertain translucency are fit for discolored tooth and fluorotic teeth;As forrelatively opaque posterior tooth, upcera Zirconia may be advisable.3.Before veneered, IPS e.max Press have the highest relative translucency, andthey obviously are influenced by background materials;Lava Zirconia andZenostar are moderately obvious,and gold pole-core materials are available forthem;there is no influnence of background on upcera Zirconia.4.After veneered, the influence of background on IPS e.max are the mostobvious,so it is fit for adopting non-metal postcores;Lava Zirconia and Zenostarhave both high strength and certain translucency,postcore could be chosenaccording to clinical demand.Upcera Zirconia have the lowest translucency andgood shading effect,and there is no influence of background on it.