The Marginal Integrity And Shear Bond Strength Of Different Enamel Surface Treatment Techniques On Pit And Fissure Sealant,an Vitro Study

Objective:Compare the difference in penetration depth,microleakage,microstructure and shear bond strength of different enamel surface treatment.Evaluate the sealing performance of Single bond universal adhesive and Beautisealant self-etching system to provide experimental basis for clinical application.Materials and methods: 40 extracted third permanent molars and 20 extracted premolars were randomly divided into 4 groups for the experiments.Group A: 37%phosphoric acid + Clinpro Sealant;Group B: Beauti Sealant Primer + Beautisealant Paste;Group C: 37% phosphoric acid + Beauti Sealant Paste;Group D: Single bond universal adhesive + Clinpro Sealant.(1)Dye penetration test40 extracted fresh third permanent molars were randomly divided into 4 groups each containing 10 teeth.Eight samples were randomly selected after the pit and fissure were sealed according to the grouping requirements.In the next step,eight teeth from each group were artificially aged in a thermocycling bath,between 5℃ and 55℃,for500 cycles with a transfer time of 10 s and a dwell time of 30 s.Each tooth’s crown was immersed in a 1% methylene blue stain solution for 24 h at 37℃.The crowns of each tooth were sectioned into two parts,from proximal to distal,with a low-speed rotating diamond blade.The extent to which the stain had penetrated the teeth was recorded using a stereomicroscope at 40 x magnification.(2)Scanning electron microscope testTwo teeth were randomly selected from each group of sealed teeth in the dye microleakage test for scanning electron microscopy(SEM).The overall combination of sealant and enamel surface was observed at 100× magnification.At 1000×magnification,the microstructure of the bonding interface between the sealant and enamel was observed and the microcrack width(μm)between the sealant and enamel was measured.(3)Shear bond strength testThe 20 premolars were randomly divided into four groups with 5 teeth in each group.A flat enamel bonding surface,larger than 3 mm in diameter,was polished onto the proximal or distal surface of the crown with an 800 mesh silicon carbide sandpaper.Cylindrical plastic molds(5 mm in height and 3 mm in diameter)were placed onto the flat treated enamel surface.Tacky wax was applied around the perimeter of the mold to prevent uncontrolled leakage of the sealant onto the enamel.According to the sample preparation method in the microleakage experiment,the sealant was put into the mold to make a sealant column with a diameter of 3mm and a height of 5mm,and the mold was removed after light curing.The shear bond strength of each group was tested by Electronic Universal Material Testing Machine.Results:(1)There was no statistical difference in penetration depth between the four groups(P>0.05).Fissure sealants on the teeth in Group D(Single Bond Universal Adhesive and Clinpro Sealant)showed significantly more microleakage and less internal sealing when compared with the teeth in the other three groups(P<0.05),however,there was no significant difference between the other three groups(P>0.05).(2)Scanning electron microscopy observation showed that there was no close connection between the sealant and the enamel at 100× magnification in group D.And the microcrack between the sealant and the enamel was about 2 μm at 1000×magnification.The width of the microcrack was visibly larger compared to the other three groups.In group B,the sealant was also fully penetrated into the bottom of the pit at 100× magnification.The width of the microcrack between the sealant and the enamel was about 1 μm at 1000× magnification.In the two groups of phosphoric acid etching,the enamel was fully combined with the sealant at 100× magnification,and the microcrack was both less than 1 μm.(3)Compared with the self-etching groups,the traditional acid etching groups had better shear bond strength.Compared with the phosphoric acid etching groups,the shear bond strength in group D was poor(P<0.05).However,the shear bond strength in group B was general,there was no significant difference compared with the phosphoric acid etching groups(P>0.05).Conclusion: The fissure sealing ability of the self-etching primer(Beauti Sealant Primer)compared to the conventional acid etching method was found to be equally effective at reducing microleakage.There was no difference in edge microleakage and SBS between the two methods.The use of the Beauti Sealant system is recommended.For uncooperative children,the new self-etching primer and fissure sealant(Beauti Sealant system)can reduce operation time and difficulty.Due to reduced SBS coupled with increased microleakage the use of the eighth generation Single Bond Universal Adhesive with Clinpro Sealant is not recommended.For cooperative children,after preparation of the teeth with conventional acid etching,the use of either Beauti Sealant Paste or Clinpro Sealant is recommended.When comparing the two products there was no difference in microleakage and SBS.