First quantitative data on the carious enamel pore volume infiltrated by a foreign liquid

  Enamel birefringence was explored to derive the first absolute quantitative data on the carious enamel pore volume infiltrated by a foreign liquid. Previous studies reported measurements of the amount of foreign liquid infiltrated in the carious enamel pores (Darling et al., Arch Oral Biol, 5:251-73, 1961), but they were relative measurements and did no take into account the organic and water volumes found in the pore volume. Relative measurements mean that all component volumes were not actually measured experimentally; i.e., they did not describe values of the mineral, water, organic, and infiltrant volumes. For example, tt was not possible to say that the mineral volume was 80%, the water volume was 10%, the organic volume 5% and the infiltrate volume 5%. This was one of the important gaps in current knowledge.  
   Meira et al. (Arch Oral Biol, 2015, http://dx.doi.org/10.1016/j.archoralbio.2015.03.001) reported absolute values of the organic, firmly bound water, air, and infiltrant volumes in natural enamel caries. Two liquid infiltrants with penetration coefficients of 2300 cm/s and 3200 cm/s were tested. From 3% to 30% of the pore volume of the surface layer of carious enamel were infiltrated by the liquids.  Most of the pore volume was occupied by organic matter. This evidence indicates that remineralization is not expected to provide full recovery of the mineral lost in carious enamel, and that resin infiltration is not expected to fill the entire pore volume of carious enamel. Absolute data on the pore volumes might provide new insights on how to improve remineralization and resin infiltration of enamel caries lesions.
   Once the pore volume is known, the important research question is how much of it is available for remineralization/infiltration, and what pore component could be removed to improve remineralization/infiltration.