Lipids in Enamel and Dentin: Involvement in Mineralization
In mineralized dental tissues, lipids are minor components of the extracellular matrix. About 66 percent of lipids are extracted from the mineralized enamel or dentin, and 33 per cent is removed after demineralization. Lipid composition suggests that the first extract is associated with biological membranes whereas the second extract obtained after demineralization is linked to the mineral phase. Histochemical staining was for a long period of time limited to Sudan black, but the conclusions were that this method identified proteins rather than true lipids. Two other methods (malachite green and iodoplatinate) allowed to identified lipids and phospholipids on sections of dental mineralized tissue. A series of drug-induced lipidosis were unable to provide any conclusive answer regarding the role that lipids may play in the mineralization of dental tissues. Fatty acid deprived diet and zinc-deficient food intake, or using pharmacological drugs such as chloroquine or suramin, inducing lipidosis, displayed cell alterations, but did not provide a clear-cut explanation on the lipid implication in mineralization. Similar results were obtained investigating the Fabry mice, and/or Krabbe disease, that displayed genetic lipidosis. Gene encoding the neutral sphingomyelin phosphodiesterase 2 enzyme (Smpd3) deficiency lead to a complete loss of enzymatic activity and subsequently to a lipid deficit (fragilitas ossiumfro/fro mice). This mutation provide evidence that lipids (and/or phospholipids) play a crucial role in dental and bone mineralization, but despite all the progress which were made, the actual mechanisms need still to be elucidated.
Keywords: Phospholipids, Sudan black, malachite green, iodoplatinate, gene mutation of sphingomyelin phosphodiesterase (SMPD3), fro/fro mice, enamel, dentin, bone.
Citation: Goldberg M. “Lipids in Enamel and Dentin: Involvement in Mineralization”. SVOA Dentistry 2:2 (2021) pages 82-90.
