Can We Consider Vital Pulp Therapy Without Pulp Volume Loss?

Objectives: Vital pulp therapy implies pulp dressing with a biocompatible material which leads to a protective tertiary dentin secretion. Currently, this dentin is secreted at the expense of the pulp volume. However, maintaining the pulp volume is pivotal to avoid additional tissue loss in case of secondary caries. The objective of this work was to develop a collagen-based biomaterial with a controlled release of Complement bioactive C5a to induce both regenerating the missing pulp and a site-specific stem cell recruitment.
Methods: C5a was encapsulated in Poly Lactic-co-Glycolic Acid microspheres using the water in oil emulsion method. The microspheres were then loaded into in the upper phase of bi-phasic collagen (1,5%) sponges. C5a release from the sponges was quantified by ELISA for 30 days. The toxicity was evaluated on pulp cells using the MTT test and on the dental pulp using the entire tooth culture model. The effect of C5a released from the biomaterial on dental pulp stem cell (DPSC) migration was investigated using Boyden Chambers. A specifically designed 3D printed device was used to investigate the sponge colonization by the pulp cells.
Results: After a burst at day 1, C5a was continuously released until 30 days. The microspheres-containing collagen sponges showed no toxicity to pulp cells and the entire tooth culture histology showed a healthy pulp in contact with the collagen sponges. C5a release form the collagen sponges increased DPSC recruitment. Also, pulp cells migrated into the 3D-specifically printed device and were found inside the collagen sponges migrating towards the C5a-containing phase.
Conclusions: This new material allowed pulp cell colonization and guiding DPSC recruitment following a C5a release which has been previously shown to induce DPSC differentiation. These results show that the new material holds promise of a potential use both for dentine and pulp regeneration without pulp volume loss.