Effects Of The Application Modes Of Self-etching Silane Primer On The Bonding Strength Between Domestic Dental Glass Ceramics And Resin Cement

Objective:To investigate the effects of application modes(time and temperature)of self-etching silane primer which named Monobond Etch&Prime(MBEP)on the short-time and long-time bonding strength between ceramics and resin cement.The results will provide laboratory basis for clinical application of MBEP and domestic dental glass ceramics(UP.CAD)Methods:The study was divided into three parts.Part one:To investigate the effects of different application time of MBEP on the short-time bonding strength between ceramics and resin cement.The standard specimens were divided into six experimental groups(n=8).One group was set as control group.As for the other five groups,MBEP was applicated on the surface of specimens according to the following procedure:after rubbed for 20s,the specimens were rested for 0s/40S/80s/120s/160s separately for sufficient reaction.The Shear bonding strength(SBS)was tested and the fracture modes were observed.Besides,Surface morphology observation,fourier transform infrared spectroscopy(FTIR)and three-point bending strength test were carried out to study the influence of different application time on the bonding strength and mechanical properties of UP.CAD.Part two:To investigate the effects of application temperature of MBEP on the short-time bonding strength between ceramics and resin cement.The standard specimens were cut into three experimental groups(n=8).MBEP was applicated on the surface of specimens according to the following procedure:after rubbed for 20s,the specimens were rested in an air circulation oven for 120s in which the temperature remains at 20/60/100℃ separately.The Shear bonding strength(SBS)was tested and the fracture modes were observed.Also,FTIR was carried out to analyse the amount of Si-O-Si bond.Part three:To investigate the effects of thermal cycling on the long-time bonding strength between ceramics and resin cement.The specimens were randomly divided into two experimental groups(n=16).In one experimental group,MBEP was applied according to the procedure:after rubbed for 20s and rested to react for 120s at a 60℃ temperature;In the other group,hydrofluoric acid(HF)and silane coupling agent(Monobond N,MBN)were used on the surface of specimens according to following steps:After etched with 4.5%HF for 30 seconds,MBN was coated on the surface and exposed to 60℃ hot air for 60 seconds.And then each group is divided into two subgroups,one subgroup for immediate SBS test and the other subgroup for long-time SBS after 12000 times thermal cycling.Results:1.When MBEP remains for further 120s after rubbed for 20s,the maximum SBS(16.72±4.79MPa)was observed.When the rest time was longer than 120s,the SBS began to decrease,but the decrease was not obvious(P>0.05).The results of scanning electron microscopy(SEM)showed that the dissolution caused by MBEP on the surface of specimens was confined in the glass matrix,and there was no obvious exposure of lithium disilicate crystal.FTIR showed that the amount of Si-O-Si bond ordered from large to small was 40s>80s>120s>160s>0s.The results of three-point bending strength showed that the measured three-point bending strength in this study was 328.86±52.59MPa,and when the rest time was between 0s to 160s.The three-point bending strength of specimens after surface treatment with MBEP decreased gradually,but there was no statistical significance(P>0.05).2.When the rest time was exposed to 60℃ hot air,the measured SBS reaches the maximum(16.59±1.59MPa).FTIR shows that when the application temperature was 60℃,the amount of Si-O-Si bond on the surface of specimen was the highest,followed by 100℃,and the lowest at 20℃.3.There was no significant difference on the SBS between the HF-MBN group and the MBEP group(P>0.05).However,SBS decreased significantly both in MBEP group and HF-MBN group(P<0.05).Conclusion:1.Under the same experimental conditions,the best application modes of MBEP on the UP.CAD is rubbed for 20s and remains for further 120s.The exposure to 60℃ hot air will obtain increased bonding performance on the basis of normal room temperature(20℃);2.Both the traditional surface treatment method(HF-MBN group)and the new simplified surface treatment method(MBEP group)can achieve reliable and similar bonding effect between ceramics and resin cement;however,the thermal cycling significantly decreased the SBS between ceramics and cement resin both in MBEP group and HF-MBN group.