Tooth enamel as an archive of early life experiences

Structure of tooth enamel

Perikymata 

A human tooth crown captured using the Alicona 3D InfiniteFocus imaging microscope.

Perikymata are a series of wavelike ridges and troughs on the enamel surface, formed by the incremental growth in enamel. 

The number and spacing of perikymata can provide information about

• crown formation times 
• underlying developmental processes
• childhood growth disruptions

Enamel hypoplasias 

Enamel hypoplasias are defects in the enamel structure caused by a disturbance in the normal process of enamel matrix production. 

Linear enamel hypoplasias are defined as an increased spacing between perikymata. 

We can create a timeline of growth disruption during an individuals childhood by following the sequence of these enamel defects across successively forming teeth that overlap in their developmental schedules. 

Alicona 3D InfiniteFocus imaging microscope

We are using the Alicona 3D InfiniteFocus imaging microscope to 

• identify perikymata 
• quantify normal and abnormal variation in spacing patterns

Individual perikyma grooves are identified on a profile from a virtual reconstruction of the enamel surface 

Direct distances between successive pairs of perikyma grooves are then calculated from coordinate data.

Chemical composition of tooth enamel

The chemical composition of subsurface enamel reflects 

• dietary intake
• other environmental exposures 

during the period of enamel formation. 

This information can be used to address a range of questions relating to 

• changes in diet 
• seasonal migration
• lifetime migration

Analysis of successively forming teeth can be used to

•  track dietary transitions during the first few years of life
•  including the transition from placental nutrition to suckling 
•  the first intake of solid foods

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) 

We use laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to undertake in situ analysis of discrete samples of enamel and dentine ablated from dental thin sections.