Microscopic movement of fluids or contaminants across a barrier or between chambers that cannot be observed without magnification.
The microscopic seepage of oral fluids between the interface of the tooth and a dental restoration. Microleakage may lead to sensitivity or discoloration of the tooth. Caused by discrepancies between the coefficient of thermal expansion of the tooth structure and the restorative material, microleakage is an inherent weakness of many restorative materials, although it is minimal with glass ionomer and polycarboxylate cements.