| Along with the development of the resin restorative materials and human aestheticrequirements，light cure composite resin in the clinical application are used more and morewidely. Composite resin curing process caused by polymerization reaction leads to acontraction which contributes to edge leakage and secondary caries. Multi-layer techniquecan make composite resin for the restoration of the minimum contraction and maximumdegree of polymerization and ensure the margin seal and bonding strength. However, lightcure composite resin will form a layer after each exposure, which is on its surface and has acertain thickness. This sticky and not well cured layer is known as oxygen inhibitedlayer(OIL). The traditional opinion towards OIL is: the existence of OIL for composite resininterlayer bonding is indispensable, the resin on both sides of interface can diffuse throughthe OIL, at the same time, there are copolymerization, thus lead to increasing of the bondingstrength. The current attitudes towards the relationship between OIL and bonding strengthare not consistent, mainly have three viewpoints:(1) OIL is indispensable and increases thebonding strength;(2) the existence of OIL reduce the composite resin bonding strength;(3)the existence of OIL has no significant effect on bonding strength. Researches on OIL focuson the thickness of OIL,the degradation of photoinitators and the degree of convertion, therelationship between OIL and the bonding strength. For the relationship between OIL andthe bonding strength, researches are made by simulating in-vitro resin model established bymuti-layer technique, contrasting shear bond strength, microtensile strength and the tensilestress with/without OIL. Due to the rubber isolation technology is not yet widely used inclinical,during the application of dental clinical doctors for restoration of compositeresin,saliva contamination is inevitable. At present, researches on OIL and the interlayerbonding of fresh cured resin surface after saliva contamination and re-treatment is rare, Thisexperiment focus on SEM observation of the oxygen-inhibited layer and the interlayerbonding of fresh cured resin surface after saliva contamination and re-treatment,aim to find agood method for rebuilding the interlayer bonding by observing the influence of differentsurface treatment on OIL and interlayer bonding. This material of this experiment is Japan Tokuyama ESTELITE∑QUICK light curecomposite resin.The model simulates fresh cured resin surface of saliva contamination invitro.Respectively, the resin surface is saliva contaminated, etched,coating adhesive.Samplesare caught SEM photograph of the single-layer superficial surface,fracture surface andfracture surface with incremental layer. Compare SEM morphological performance, theinfluence of different condition on OIL and interlayer bonding is variant.Finally results are found as follows:(1)In the process of composite resin filling, theintegrity and contamination-free of the interlaminar OIL lead to the best combination of theresin layers.(2)Coating adhesive after saliva contamination/etching the surface areconducive to the resumption of the interlayer bonding,from the morphological, coatingadhesive after saliva contamination is more conducive to the resumption of the interlayerbonding.(3)Saliva contamination, etching cause vary degrees of damage of the OIL, both ofwhich cause the seal between layers decreased, and not conducive to the resumption of theinterlayer bonding.The experiment focuses on the influence of contamination and re-treatments on OILand interlayer bonding of fresh cured resin surface.We discuss the effects of themorphological range, for deeper research on the bonding strength, bond strength test will betaken, This experiment lays a good foundation for the subsequent research. |
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