In a healthy tooth, the visible part is the enamel, akin to a glaze, covering the underlying dentin. The dentin surrounds the pulp, while the dental cementum and periodontium encase the root up to the tooth’s neck.

Figure 1. A tooth in cross-section.

 

What is the main component of our teeth?

A) calcium phosphate hydroxylapatite, Ca₅(PO₄)₃(OH)

B) calcium fluorophosphate, Ca₅(PO₄)₃F

C) chlorapatite, Ca₅(PO₄)₃Cl

D) carbonate fluorapatite, Ca₅(PO₄,CO₃OH)₃F

E) montmorillonite, (Na,Ca)_0.33(Al,Mg)₂(Si₄O₁₀)(OH)₂·nH₂O