INVESTIGATIIONT OF CONIC FLOW POINT IN ADHESIVE SYSTEMS BY USING HEPPLER CONSISTOMETER

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When restoring wedge-shaped tooth defects, the adhesive system, and in particular, its microhardness provided by an inorganic filler plays a significant role in withstanding the masticatory load. The conic flow point is a measure for the microhardness of spatially-stitched polymer matrices and depends on the nature, structure, density of the polymer chains. The purpose of this work is to compare the properties of analogues: the Conic Flow Point of 5th DC Adhesive NF Adhesive Systems (Dental Central) and the 7th Single Bond (3M ESPE) by using Heppler consistometer under laboratory conditions.
 The study was carried out on adhesive plates manufactured directly in the laboratory before testing. The samples were divided into two groups depending on the adhesive system used: 10 samples of 5 generations (DC Adhesive NF, Dental Center) and 10 samples of 7 generations (Single bond Universal 3M ESPE). To obtain specimens of adhesive systems of 3.0 ± 0.2 mm high, a metallic mould covered with silicone was used. On the back side of the mould we put a sheet of lavsan film, turned the mould upside-down, then put the adhesive into the mould and covered with lavsan film. Then this sample was irradiated with a photopolymerizer for 40 seconds. Without removing the film, the sample was turned over and its other side was irradiated for 40 seconds. Then we peel off the film and take out finished sample from the mould. Prior to testing, samples were kept in distilled water at a temperature of (37 ± 2) ºC for 24 hours.
 According to relevant literature data and research data reported by 3M ESPE and Dental Central firms, no studies for assessing conic flow point by using Heppler consistometer for 5th and 7th generation adhesives were carried put under laboratory conditions. Out test results have demonstrated the regularity that the harder an adhesive is, the higher values of the conical flow point. That is, the adhesive can withstand a load that is positive for retorting cervical defects.
 Thus, the restoration of wedge-shaped defects requires a competent and differentiated approach to the choice of adhesive system in order to obtain positive results and to avert spreading of pathological process that ensured the treatment efficacy. The use of 5th generation AD Adhesive NF promotes the formation of a complete hybrid layer, firm bonding between composite material, dentin and enamel, provides effective sealing at the edge of filling margins with dental tissues and their resistance due to adhesive ductility: all this guarantees the durability of the restorations performed.