Effect Of Different Surface Modification On Resin Composite Bonding To Bio-HPP

As a kind of prosthetic material,Bio-HPP is grayish pigmentation and low translucency.Therefore,the outer surface should be modified by veneering resin.It is difficult to achieve adequate bond strength to composite resin materials owing to its low surface energy and resistance to surface modification by different chemical treatments.Currently,many scholars come up with different surface modifications,such as sand blasting、acid corrosion,to improve the surface adhesion properties of various materials.In this study,a new method of surface modification of Bio-HPP was proposed and the effects of different surface treatments such as acid etching and sandblasting were evaluated to provide reference for clinical application.Objective The surface modification of Bio-HPP was carried out by different surface treatments,such as sandblasting and acid etching,and the bonding strength of the samples was measured and the mechanism of surface modification of Bio-HPP by different kinds of conditions were studied.Materials and methods 1、The prepared samples were randomly divided into 5 groups,21 specimens in each group(20 specimens and 1 used for XPS analysis),respectively: A(Untreated group),B(Sandblasting group),C(Piranha acid group),D(98% sulfuric acid group),E(98% sulfuric acid heating group).2、Effect of different surface modification on the surface roughness is compared via the surface roughness measurement.The changes of the ultrastructure of the surface is compared via SEM by means of observing surface morphology of specimens.XPS is used to analyze the specimens coping with different surface modification.3、The specimens were bonded with resin(Visio.link/Crea.lign),LED light solid,placed at room temperature 30 min,and then putting it in 37℃ water 24 h.4、Adhesion samples in the hot and cold circulation box,hot and cold cycle 5000 times,and then testing sample shear strength by universal test machine.5、The fracture surface was photographed and classified by stereo microscope,and SEM was used to observe the representative fracture mode.6、Single factor analysis of variance,linear correlation and regression analysis were carried out by SPSS17.0 software.Results 1.After different surface modification for samples,roughness measurement results : A(Untreated group)0.073 um,B(Sandblasting group)1.485 um,C(Piranha acid group)0.103 um,D(98% sulfuric acid group)0.716 um,E(98% sulfuric acid heating group)1.108 um,and we can see that the roughness between the groups of A(Untreated group)and C(Piranha acid group)has no statistical difference(P﹥0.05),and B(Sandblasting group),D(98% sulfuric acid group),E(98% sulfuric acid heating group)have statistical difference(P﹤0.05).2.The analyzed results of samples with XPS showed that absorption peak of C1 s has no difference between groups of untreated、sandblasting、piranha acid、98% sulfuric acid heating,however,absorption peak of C1s291.8e V’s π-π* was disappeared and an additional O-C = O contribution is showing up at 289 e V in group of 98% sulfuric acid.3.Surface morphology of specimens via SEM shows that there are obvious changes between untreated group and treated group,such as Al2O3 embedded in the sandblasting group(B),piranha acid(C)mesh less and scattered,98% concentrated sulfuric acid group(D)fiber mesh evenly distributed,98% concentrated sulfuric acid heating group(E)the fibers appear thinner,elongated and discontinuous.4.The shear bond strength results: A(Untreated group)0MPa,B(Sandblasting group)8.334 MPa,C(Piranha acid group)2.913 MPa,D(98% sulfuric acid group)18.504 MPa,E(98% sulfuric acid heating group)14.036 MPa,and we can see that: D(98% sulfuric acid group)> E(98% sulfuric acid heating group)> B(Sandblasting group)> C(Piranha acid group)> A(Untreated group),and there was statistical difference between the groups(P<0.05).The fracture surface was observed by stereo microscope,D(98% sulfuric acid group),E(98% sulfuric acid heating group)were mix failure;B(Sandblasting group),C(Piranha acid group),A(Untreated group)were mainly for interface failure.5.There is a certain correlation between roughness and shear strength,but not linear correlation.Conclusion 1.Concentrated sulfuric acid is an effective method to improve the bonding strength between Bio-HPP and resin.2.98% concentrated sulfuric acid group can open chemical bond’s π-π of peek,exposed more functional groups,improving the bonding strength.3.The bonding properties of Bio-HPP are related to roughness,rough surface structure and chemical bond 4.80℃ concentrated sulfuric acid failed to expose more functional groups to the surface of Bio-HPP.