Mechanobiology of Dental Pulp

Session

AFM in Life Sciences

Authors

Ms Laura Whitehouse (1), Dr. Jing Kang (1), Dr. Thuy Do (1), Dr. Neil Thomson (1)

Affiliations

1. University of Leeds

Keywords

AFM, nanoindentation, force volume mapping, dental pulp stem cells, collagen, caries, confocal microscopy

Abstract text

Dental pulp inside teeth is a complex biological tissue which remains vital while the biomineralised enamel and dentine layers remain intact. The predominant protein structural component of the pulp is a network of type I collagen fibres, giving it hydrogel properties with a high aqueous content and low elastic stiffness (~100-150kPa).

When teeth are damaged or decayed, the pulp becomes inflamed, leading to intricate biological and mechanical tissue changes. Dental pulp stem cells (DPSCs) residing within the pulp become activated following biomechanical cues, leading to their migration towards the pulp/dentine interface. Upon differentiation into odontoblast cells at the site of injury, they deposit dentine in an attempt to repair the hard tissue barrier. DPSCs are known to undergo differentiation in response to biochemical cues but also respond to stimulation from their environment, including mechano-sensitisation and transduction.

We are investigating the mechanobiology of pulp, to correlate genotype changes to the phenotype response and any concomitant changes in mechanical properties. Pulps of sound and carious extracted human teeth have been investigated and compared using a multi-disciplinary approach. The elastic modulus distributions of pulp have been determined by nanoindentation mapping using AFM. The pulpal collagen structure has been investigated with confocal fluorescence microscopy, while differential gene expression is assessed using RNAseq analysis.

Our results show statistically significant differences between the mechanobiology of pulps from sound and carious teeth. We will present and discuss the correlations between changes in the gene expression, collagen fibrosis and the consequent mechanical response of the pulp.