Dentine and Pulp

Dentine may be studied in both ground sections (where the mineral is retained and the section is unstained) and demineralised sections (where the mineral is removed and the section is stained) whereas pulp can only satisfactorily be studied in demineralised sections .

A characteristic feature of dentine is the presence of channels running through it from the pulp to the outer dentine surface – these are called dentinal tubules. These tubules contain fluid and a long process from the cells responsible for forming and maintaining the dentine – the odontoblasts. The tubules are not straight. They follow an overall ‘S’ shaped path called the ‘primary curvature’. Superimposed on this ‘long wavelength’ curvature are much more frequent, small wave-like deviations called the secondary curvature. The tubules may also be branched, particularly evident at the amelo-dentinal junction immediately under the enamel in the tooth crown.

There are three slides available to study the various aspects of dentine and pulp structure and one slide demonstrating the reactionary structures in dentine resulting from an overlying enamel caries lesion. Three ground sections and one demineralised and stained. Slide 1 is a ground section where the tooth is sectioned in a transverse plane through the enamel and dentine (this is the same section available to view structures in enamel). On this slide there are examples of interglobular dentine, tubule branching and secondary curvatures of the tubules. Slide 2 is also a ground section but in the longitudinal plane where primary and secondary tubule curvatures, tubule branching, secondary dentine, dead tracts, the granular layer of Tomes and the hyaline layer are evident. Slide 3 is a demineralised and stained transverse section through a root showing dentine, the pulp/dentine interface and the pulp. Slide 4 is a longitudinal ground section of a tooth showing sclerotic and reparative dentine and dead tracts.