Elastic Modulus of Bovine and Human Dentin at the Enamel-Dentin and Dentin Pulp Junctions: An In Vitro Experimental Study

Background: The use of bovine dentin in dental research has gained relevance due to its easy availability, lower structural
and compositional variability, and morphological similarity to human dentin. Purpose: To compare the elastic modulus of
human and bovine dentin at the dentinoenamel junction and the dentin-pulp junction. Methods: An in vitro experimental
study was conducted on 30 recently extracted human molars (20–30 years old) and 30 bovine incisors (2–3 years old). The
teeth were preserved in 2% chloramine T to maintain moisture. Thirty dentin bars were obtained: 15 from the dentinoenamel
junction and 15 from the dentin-pulp junction. Each bar measured 2 mm wide by 1.5 mm thick. The specimens were observed
under a stereomicroscope and measured with a digital caliper. The data were entered into the three-point bending test program
(Instron® universal testing machine) to calculate the elastic modulus. The test was performed using two instruments designed
for the setup: a sample holder and a load application pin (p = 0.05). Results: In human dentin, the elastic modulus was 8.89
GPa at the dentinoenamel junction and 6.7064 GPa at the dentin-pulp junction. In bovine dentin, it was 9.0078 GPa at the
dentinoenamel junction and 6.0388 GPa at the dentin-pulp junction. Conclusions: The elastic modulus values in human and
bovine dentin, both at the dentinoenamel junction and the dentin-pulp junction, do not suggest significant differences.
Keywords: biophysics; bovine dentin; dental biology; dentin biomechanics; dentinoenamel junction; dentin-pulp junction;
dentistry; elastic modulus; experimental research; human dentin