# Bone Tissue Bioengineering for Craniofacial and Dental Applications: Association of Deciduous Dental Pulp Stem Cells to Carbonated Hydroxyapatite

## TL;DR

This study shows that combining deciduous dental pulp stem cells with carbonated hydroxyapatite improves bone regeneration in rats, offering a promising alternative to traditional bone grafts.

## Contribution

The novel contribution is demonstrating enhanced bone regeneration using DDPSCs and cHA in a critical-size defect model.

## Key findings

- At 90 days, DDPSC + cHA significantly increased bone formation compared to acellular cHA.
- DDPSC-treated defects showed complete scaffold resorption, while cHA scaffolds had residual material.
- The DDPSC + cHA group had significantly less connective tissue at 90 days.

## Abstract

Autogenous grafts remain the gold standard for repairing extensive maxillofacial bone defects, but their associated morbidity motivates the search for alternative strategies in tissue bioengineering. Deciduous dental pulp stem cells (DDPSCs) represent a promising cell source due to their accessibility, multipotency, and osteogenic potential, while nanostructured carbonated hydroxyapatite (cHA) microspheres exhibit biochemical similarity to bone mineral and favorable bioabsorption. This study investigated the osteogenic response induced by the association of DDPSCs with cHA in a rat calvaria critical-size defect model. DDPSCs were expanded, seeded onto cHA microspheres, and characterized in vitro prior to bilateral implantation in 12 Wistar rats, with each animal receiving cHA + DDPSC on the right defect and acellular cHA on the left. After 60 and 90 days, histological and histomorphometric analyses revealed new bone formation in both groups, predominantly from the defect margins toward the center. At 60 days, no significant difference in newly formed bone was observed between groups (p = 0.249). At 90 days, the DDPSC + cHA group demonstrated significantly greater bone formation compared with acellular cHA (median 40.70 vs. 11.10 histomorphometric points; p = 0.028) and significant reduction in connective tissue (p = 0.028). Complete scaffold resorption was observed in all DDPSC-treated defects at 90 days, whereas residual biomaterial persisted in the cHA group (p = 0.015), indicating progressive cHA resorption over time. These findings suggest that combining DDPSCs with cHA enhances bone regeneration and that this synthetic, bioabsorbable scaffold represents a promising strategy for future applications in bone tissue engineering.