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Biology Articles » Anatomy & Physiology » Anatomy, Human » Ameloblasts – makers of the tooth enamel

Ameloblasts – makers of the tooth enamel

Ameloblasts – Makers of the Tooth Enamel

   
Tooth (molar) showing the enamel

Image source: Wikipedia

Our bones are hard and strong and tough. Some of the long bones, like the femur, separated from a dead person’s skeleton, can be used as a club to hit hard in defense or for offence. Though they are strong, the bones are not the hardest part in our body. There is something even harder than the bones.

The enamel of the tooth is the hardest and the most mineralized part of our body. It contains just about four percent water and cementing material; all the rest of the matter in it is the hard calcium mineral. A thin layer of the enamel protects the crown of each tooth naturally against the forces of grinding and chewing.

The tooth enamel is translucent, that is semitransparent, and gives the tooth qualities of a gem--opal. With advancing age the surface texture gets lost making the tooth appear dull. Enamel may get stained due to smoking, drinking cups of strong coffee or drinking red wine. If the enamel on your teeth is thin, then the layer underneath, called the dentin which has a yellowish or brownish hue may start to show through the enamel. This one reason why we should not use a harsh tooth brush or use abrasive tooth paste which may gradually wear out the enamel.

The teeth enamel formation takes place in a group of cells called the enamel organ, with the help of ameloblasts. Derivatives if these cells called prismatic cells form proteins such as – amelogenin, ameloblastin or amelin, enamelin and tuftelin. In the soft enamel protein matrix are deposited minerals like calcium and phosphate in a process known as biomineralization. Laying down the soft, pliable protein matrix is the secretory stage and takes place fist. It is followed by the maturation stage, in which enamel rods or prisms are laid in a specific manner and enamel mineralization is completed.

A one and half month old baby has front teeth, the central incisors with teeth enamel completely mineralized. The incisors on sides, the canine teeth and the molars progressively later complete mineralization. By the age of one year even the second molar teeth show complete mineralization. If one takes a cross-section of a crown of tooth, one finds brownish lines called striae of Retzius that look like concentric rings similar to the annual rings on a tree. Interestingly as the interval between two successive brown striae of Retzius in the enamel is of about seven to ten days some chronobiologists designated the interval as a bioweek. At one time these lines were thought to be produced because of air but now are believed to be the hypomineralized bands .

Written by Narayan Dattatray Wadadekar
Source: Suite101, August 21, 2005

 

 


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