Luting agents comprise a broad category of materials used to attach and seal dental restorations and prosthesis to teeth. New luting agents, particularly with adhesive capability, are being introduced in an attempt to improve clinical success. The choice of luting agents is dependent on the clinical situation combined with the physical, biological, and handling properties of the luting agent. Several workers have reported that mechanical properties of encapsulated materials were inferior or equivalent to those of the hand-mixed materials. It was recognized that mechanical mixing may result in the incorporation of air porosity in the cements, leading to the weakening. If the porosity in dental luting cements is to be minimized, a better understanding of the nature and origin of such voids is necessary. In particular, information is required about the number, size and morphology of such pores, which will determine the extent of their likely adverse effects.This book will elaborate on the effect of mixing method on the percentage of porosity in selected luting cements