cosmetic dentistry_ beauty & science International

I 17 industry report _ CLEARFIL SE BOND I cosmeticdentistry 3_2011 andtheplacedresincompositepasteafterlightirradi- ationfortenseconds. Another important feature of CLEARFIL SE BOND is that the acidity of the primer is optimised to allow simultaneoustreatmentofbothenamelanddentine layers.Itisabletoetchtheenamelcavitywallenough to ensure good bonding, while not damaging the collagen structure of the dentine cavity wall ex- cessively. Additionally, the primer remains diffused throughout the dentine tissue after treatment, since there is no rinsing away with water. Therefore, the collagennetworkstructureinthedentinecavitywall prevents the structure from collapsing, and thus al- lows excellent penetration of the bond component throughout the supported dentine structure. The primer reverts to a neutral pH during treatment and demineralisation. The primer and bond are able to produce a strong and stable bonding layer with ex- cellent dentinal sealing, which could contribute to much-reduced sensitivity. Up until now, it was believed that self-etching primers were unsuitable for performing veneer restorationsondiscolouredteethwithalargeenamel surfaceareainthecavityowingtothelowetchingef- fect of most primers. It has also been reported that marginalbrownlinesappearedalongenamelmargins when the existing self-etching primers were used to perform adhesive restorations. However, Kuraray has overcome this problem with other self-etching primersbyenhancingandimprovingthemixturerate ofMDPandotheragentsinCLEARFILSEBOND. _Adhesion of CLEARFIL SE BOND The tensile bond strength of CLEARFIL SE BOND to tooth tissue was determined using extracted bovine teeth from the jaws of cattle freshly slaughtered on the morning of the test day and kept frozen until theafternoon.Becausethedentalpulpshadnotbeen removed, the adhesion tests were conducted under toughconditions. The adhesion area was regulated at 3 mm in diam- eterandthetensilestress(cross-headspeed)wassetat 1mmperminute.CLEARFILAP-Xresinpastewasused as a restorative resin and 10 minutes after bonding, the bonded assemblies were stored in 37°C tap water. The tensile bond strength of CLEARFIL SE BOND was higherthan20MPatobothbovineenamelanddentine. The thermo-cycling test of 4,000 cycles (4~60°C) produced similar results in both the enamel and den- tine. Since the resin is able to bond to enamel and dentine tissues at comparable strengths, the present systemcouldbeanidealbondingsystem,anditsbond strengthisoneofthehighestamongsttheresinbond- ing systems currently available. Additionally, since resins generally adhere to human teeth much more strongly than to bovine teeth, this would be true of CLEARFILSEBONDtoo. Fig. 4_FE-SEM (argon ion beam etched surface; x 20,000) of the resin–enamel interface. The upper half is the set bonding agent loaded with micro-filler particles and the lower half is the enamel layer. The fine etching pattern of the superficial enamel layer is very clear. Fig. 5_FE-SEM (argon ion beam etched surface; x 10,000) of the resin–intact dentine interface. The upper half is the set bonding agent and the lower half is the dentine layer. The junction between the resin and dentine was very tight through the hybrid layer of 1 µm in thickness. Fig. 6_FE-SEM (argon ion beam etched surface; x 20,000) of the resin–intact dentine interface. When subjected to the argon ion beam etching, the hybrid layer was clearly demonstrated. Fig. 7_SEM (hypochlorite treatment following phosphoric acid treatment; x 5,000) of the resin–intact dentine interface. The resin tags penetrated the dentinal tubules and penetrated lateral branches are presented. This demonstrates that the CLEARFIL SE BOND primer has a good treatment effect. Fig. 6 Fig. 7 Fig. 4 Fig. 5