Study On Microleakage Of Self-adhesive Flowable Composites In Pit And Fissure Sealing Therapy

Objective To evaluate the microleakage of Constic,a novel self-adhesive flow composites,which used as pit and fissure sealant in vitro.Compare the sealing ability with another type of self-adhesive flow composites(Dyad Flow)and Clinpro Sealant which commonly used in clinic practice.Explore the effect of acid etching on its sealing performance and provide experimental evidence for clinical application.Methods Fifty maxillary premolars extracted due to orthodontic demand were selected according to the inclusion criteria and were fully cleaned.The high-speed 1/4-ball drill with a diameter of 0.5 mm was used to establish pit and fissure model on these teeth.According to the type of sealing agent used and the application method,these teeth were divided into five groups.Group A: Constic alone;Group B: Dyad Flow alone;Group C: acid etching + Constic;Group D: acid etching + Dyad Flow;Group E: acid etching+Clinpro Sealant(control).Procedure for simulating oral environment were taken after the sample filling is completed.All samples were soaked in artificial saliva at 37°C for 7 days.Then rinse thoroughly,and soak in water baths of 5°C and 55°C 30 s respectively for hot and cold cycles,1 minute for one cycle,and totally 500 cycles were performed.After dried,root tips were sealed with melted wax,and 2 layers nail polish were smeared on the area 1 mm outside of the material edge.After dried,the sample was placed in 1% methylene blue solution and soaked for 72 hours at room temperature.Wash the surface and dry it naturally.At the three equal points,cut the crown into three parts along the buccallingual direction.The dye leakage was observed under the microscope and scored by 2 examiners who had passed the consistency test.The scoring criteria are: 0=no dye penetration;1=dye penetration depth less than 1/2 of the interface length between sealant and tooth;2=dye penetration depth exceeds 1/2 of the interface length,between sealant and tooth,but not reach the bottom of groove;3=dye penetrate into the bottom of the groove.Data was recorded and analyzed statistically.Kruskal-Wallis rank sum test was used to compare the total scores of the leakage grades in five groups.And Nemenyi method was used to compare the different between each two groups.Confidence level was set at 0.05.Results 1.There are different degrees of dye infiltration under endodontic microscope investigation between the sealant and the enamel interface in each group of samples;2.The microleakage value of A-E groups have significant difference detected by Kruskal-Wallis H test(P<0.05);3.The score of group E is significantly better than group A,B and D(P<0.05);4.There is no statistical difference between group C and group E(P> 0.05);5.There is no statistical difference between group A and B,group C and D.(P>0.05).6.There is no statistical difference between group A and C,group B and D.(P>0.05)Conclusions 1.The margin microleakage of the three pit and fissure sealing materials was observed,which not meet the demand of optimal magin sealing ability 2.Clinpro Sealant and Constic has the lowest level of margin microleakge when applicated with acid etching which indicated that Constic can obtain equivalent margin sealing ability of Clinpro Sealant when combined with acid-etching during pit and fissure sealing.3.When applicated alone or in combination with acid etching,Constic and Clinpro Sealant shows comparable level of microleakge,which suggested that these two type of self-adhesive composite has the similar margin sealing ability.4.Under our experiment condition,the effect of acid-etching on the microleakage of the Constic and Dyad Flow during pit and fissure sealing has not been observed.