The influence of cervical finish line and type of cement on microleakage

The fixed dentures are commonly used in the daily practice to restore and preserve the hard dental tissues. The appropriate marginal fit of these restorations is required in all the cases, but the appearance of marginal deficiencies is inevitable at the tooth-restoration interface. The different luting agents used at the cementation of the fixed restorations pretended to seal the gap at the restoration margins and avoid the infiltration of the fluids from the oral cavity followed by microbial invasion into the dental structures. [1]
The inappropriate use of these luting agents in vital teeth results inflammation and necrosis of the pulp, which affects the longevity of the restorations. [1, 2] The microleakage is detected by clinical signs of the chronic dental hypersensitivity and color changes of the abutment at the restoration margins. [3 The water-based cements with a high degree of solubility in the oral cavity, used in the past, served only to “fill” the space between the restoration and the abutment. The two-component, powder-liquid systems, were traditionally used to fill the gaps between the tooth and restoration. However, due to their high solubility in the oral fluids, the sealing capacity of these cements depends on the precision of the marginal fit. [4] Numerous studies demonstrated that 100-500 μm is the acceptable gap at the tooth-restoration interface regarding the protection against microleakage. [5-7]
Besides the improvement of the technological processes, different cements with adequate sealing capacity had been developed in order to minimalize the marginal discrepancies. The glass ionomer cements are effective, due to their ability to continuously release fluoride ions and also the resin cements through their ability to establish chemical bonds with dental tissues. [4, 8]
The most important features of an ideal cement are biocompatibility, sealing capability and caries prevention. Microbial infiltration may be the most critical factor influencing the long-term success of a fixed prosthetic restoration. [3]
The aim of this study was to measure the rate of microleakage between tooth and restoration according to the type of finish line and luting agent.