The same study also found that both dermal exposure to EDTA in most cosmetic formulations and inhalation exposure to EDTA in aerosolised cosmetic formulations would produce exposure levels below those seen to be toxic in oral dosing studies. Synthesis
The compound was first described in 1935 by Ferdinand Münz, who prepared the compound from ethylenediamine and chloroacetic acid. Today, EDTA is mainly synthesised from ethylenediamine (1,2-diaminoethane), formaldehyde, and sodium cyanide. This route yields the tetrasodium EDTA, which is converted in a subsequent step into the acid forms:

H2NCH2CH2NH2  +  4 CH2O  +  4 NaCN  +  4 H2O   →  (NaO2CCH2)2NCH2CH2N(CH2CO2Na)2  +  4 NH3(NaO2CCH2)2NCH2CH2N(CH2CO2Na)2  +  4 HCl  →  (HO2CCH2)2NCH2CH2N(CH2CO2H)2  +  4 NaClThis process is used to produce about 80,000 tonnes of EDTA each year. Impurities cogenerated by this route include glycine and nitrilotriacetic acid; they arise from reactions of the ammonia coproduct. Nomenclature
To describe EDTA and its various protonated forms, chemists distinguish between EDTA4−, the conjugate base that is the ligand, and H4EDTA, the precursor to that ligand. At very low pH (very acidic conditions) the fully protonated H6EDTA2+ form predominates, whereas at very high pH or very basic condition, the fully deprotonated EDTA4− form is prevalent. In this article, the term EDTA is used to mean H4−xEDTAx−, whereas in its complexes EDTA4− stands for the tetraanion ligand. Coordination chemistry principles
In coordination chemistry, EDTA4− is a member of the aminopolycarboxylic acid family of ligands.
Hypercementosis is an idiopathic, non-neoplastic condition characterized by the excessive buildup of normal cementum (calcified tissue) on the roots of one or more teeth. A thicker layer of cementum can give the tooth an enlarged appearance, which mainly occurs at the apex or apices of the tooth. Signs and symptoms
It is experienced as an uncomfortable sensation in the tooth, followed by an aching pain.It may be shown on radiographs as a radiopaque (or lighter) mass at each root apex. Cause
Can be caused by many things. A way to remember the causes is "PIG ON TAP"Local factors- 

Occlusal Trauma
Trauma
Non-functional tooth
Unopposed tooth (and impacted teeth, embedded teeth, teeth without antagonists)Systemic factors-

Idiopathic
Pituitary Gigantism
Pagets Disease
Acromegaly
Periapical granuloma
Arthritis
Calcinosis
Rheumatic feverIt may be one of the complications of Pagets disease of bone in the form of generalized hypercementosis. It may also be a compensatory mechanism in response to attrition to increase occlusal tooth height. Complications
Such deposits form bulbous enlargements on the roots and may interfere with extractions, especially if adjacent teeth become fused (concrescence). It may also result in pulpal necrosis by blocking blood supply via the apical foramen. References


== External links ==