An in vitro evaluation of microleakage in class I preparations using 5th, 6th and 7th generation composite bonding...

The intent of this study was to evaluate microleakage of newer generations of dentinal bonding systems of Class I restorations filled with the same resin based composites. Eighty extracted human premolar and molar teeth were randomly assigned to four groups for bonding: the 5th generation bonding system (Optibond Solo), the 6th generation bonding system (Prompt-L-Pop) and the 7th generation bonding system (iBond), and a control group that was used with no dentinal bonding system. Cavities were prepared 3 mm in width, 2 mm in depth and 2 mm in length. Margins of the cavities were chamfered using a high-speed hand piece with water spray and a #1/2 round diamond bur. The cavities were restored with resin based composites after the application of the dentinal bonding systems according to the instructions of the manufacturer. Upon drying of the teeth, two coats of nail varnish were applied covering the surface of the tooth, excluding the tooth-restoration interface. Samples were thermocycled and immersed in methylene blue dye (0.05%). Each sample was sectioned with an Isomet and evaluated, for microleakage using light microscopy under a measuring microscope at 50x magnification Statitical significance was determined using the Chi-Square Test. Among the three dentinal adhesive systems used in this study the 5th generation outperformed both the 6th and 7th generation bonding systems.