Calcium ions (Ca2+)

Calcium ions are the primary inorganic constituent of human dentin, predominantly organized within the hydroxyapatite crystal lattice [1]. In clinical endodontics, these ions are the specific target for chelating agents used to manage the smear layer—a tenacious film of organic and inorganic debris, including bacteria, created during the mechanical instrumentation of root canals [2]. The presence of calcium ions within this layer and the underlying dentin walls allows for the application of chemical irrigants that bind and sequester the ions, effectively softening the dentin and dissolving the inorganic components of the smear layer [3]. This process is vital for opening dentinal tubules, which facilitates the deep penetration of antimicrobial agents and ensures a superior seal with obturation materials [4]. While essential for successful root canal disinfection, the targeting of calcium ions must be carefully controlled to prevent over-demineralization, which can compromise the structural integrity and fracture resistance of the tooth [5]. Sources: [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4504022/; [2] https://pubmed.ncbi.nlm.nih.gov/12616911/; [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144047/; [4] https://pubmed.ncbi.nlm.nih.gov/11307922/; [5] https://www.sciencedirect.com/topics/medicine-and-dentistry/smear-layer.

Other names

Calcium ions in dentin and smear layerDentinal calciumHydroxyapatite calciumInorganic component of the smear layer

Chelation of divalent cations to facilitate the demineralization of hydroxyapatite and the subsequent removal of the inorganic smear layer debris.