Chlorhexidine gluconate (CHX), as an anti plaque agent, is commonly used with a variety of products. In this study we, the investigators at Hadassah Medical Organization, intend to examine the efficacy of a single dip in CHX of provisional restoration prior to oral cementation. If the protocol is effective, we intend to calibrate it and recommend clinical use of the protocol. The examination of biofilm formation will be both with electron microscope and confocal scanning laser microscope.