Elastic Modulus of Human Dental Enamel from Different Methods

Introduction

Human teeth consist generally of two different parts; the upper part (crown) is covered by dental enamel, followed by dentine and the pulp with blood vessels and nerves when going to the inner. The lower part (root) with its cementum is giving the stability to the tooth to stick fixed in the bone of the jaw. Dental enamel is the most highly mineralised and hardest biological tissue in human body (Dorozhkin, 2007). It is made of about 97% hydroxylapatite (HAP) - Ca5(PO4)3(OH), which is hexagonal (Space Group P63/m). The lattice parameters are a = b = 9.418 Å and c = 6.875 Å.

Teeth are a very important component in human body. With decayed teeth the quality of daily living, food intake and social interaction is very much reduced. Hence healthy teeth are essential needed for ingestion and their health plays also a high ranked role in social interaction. Applying normal medical care like oral hygiene or going to the dentist is not enough since even dental fillings themselves can harm the enamel of an opposite tooth hence by chewing the interaction of dental enamel and filling is not equivalent. In the worst case, the harder fillings can abrase the softer enamel. Hereby one can see the importance of knowing the mechanical properties (e.g., elastic modulus) of dental enamel and filling materials in detail.