Rheological characterization of human dental pulp tissue

Dental pulp tissue, once infected, demonstrates limited self-healing capacity, and root canal procedure remains as the best option to remedy this clinical problem. Unfortunately, this procedure requires removal of native pulp tissue, and filling the canal with a polymer. This results with a devascularized and devitalized tooth with no nerves, potentially leading to a brittle structure. Regenerative engineering, by definition, may be able to solve this problem, however, there is a lack of knowledge for the selection of appropriate biomaterials. Availability of material properties as well as biological properties of native tissues are critical for biomaterial design and synthesis for regenerative engineering purpases. Until recently, selection of biomaterials and biomolecule carriers for dental pulp regeneration has been done randomly or based on experience mainly due to the absence of benchmark data for dental pulp tissue. This study, therefore, for the first time, characterizes the linear viscoelastic material functions under oscillatory shear and compression as well as compressive properties of human dental pulp tissues harvested from wisdom teeth. The results revealed a gel-like behavior of the pulp tissue over the frequency range of 0.1–100 rps. Human dental pulp tissue possessed storage modulus (G') values changing between 2000-7000Pa, and loss modulus (G") values of around 1000Pa on average. Uniaxial compression tests generated peak normal stress and compressive modulus values of 39.1±20.4 kPa and 5.5±2.8 kPa, respectively. Taken collectively, the linear viscoelastic and uniaxial compressive properties of the human dental pulp tissue reported here should enable the better tailoring of biomaterials or biomolecule carriers to be employed in dental pulp regeneration.