What the study is

Elbaram, Sami and Al-Sultani, from Dijlah University, Al-Hikma University College and Al-Qadisiyah University in Iraq, published “Comparative regenerative effects of human dental pulp and periodontal ligament stem cells delivered on collagen-hydroxyapatite scaffolds in rabbit dental defects: An in vivo study” in Babcock University Medical Journal (2026;9(3):379-388, doi:10.38029/babcockuniv.med.j…v9i3.1848, open access, published 30 September 2026). The design: 24 white rabbits, 7 to 12 months old, allocated by lottery to four groups of six. Group I received collagen-hydroxyapatite scaffolds seeded with human dental pulp stem cells (DPSCs), Group II the same scaffold seeded with human periodontal ligament stem cells (PDLSCs), Group III the cell-free scaffold, and Group IV an empty defect. Both cell types came from extracted orthodontic premolars, were expanded in culture, and were seeded at 1 times 10^6 cells per scaffold. Animals were sacrificed at 8 weeks. The protocol was approved by the Research Ethics Committee of Dijlah University (Approval No. 17, 19 January 2025). Histology, immunohistochemistry and micro-CT readouts were, the authors state, scored by investigators blinded to group allocation.

What was measured

Cell identity was checked by flow cytometry. The reported numbers cover the DPSCs only: CD73 98.2 plus or minus 1.5%, CD90 96.7 plus or minus 2.1%, CD105 94.3 plus or minus 3.2%, with CD34 at 0.8 plus or minus 0.3% and CD45 at 0.5 plus or minus 0.2%, a standard mesenchymal profile. The PDLSCs are described as positive for CD73, CD90 and CD105 and negative for CD34 and CD45, but no percentages appear anywhere for them. Regeneration was read three ways: hematoxylin and eosin histology, immunohistochemistry for dentin sialophosphoprotein (DSPP, an odontogenic marker) and vascular endothelial growth factor (VEGF, an angiogenic marker) with H-score quantification, and micro-computed tomography for bone volume fraction (BV/TV) in the defect. Statistics were one-way ANOVA with Tukey post-hoc testing at p less than 0.05, after Shapiro-Wilk and Levene checks. The authors state that no a priori power calculation was performed; the n of six per group was chosen by reference to comparable studies and the 3Rs principle.

What was found

Two quantitative results carry the paper. First, DSPP H-scores in the DPSC group were 245.6 plus or minus 32.1, versus 78.3 plus or minus 18.5 for scaffold-only and 42.1 plus or minus 12.3 for empty defects (p less than 0.001). Second, micro-CT bone volume in the PDLSC group was 34.2 plus or minus 5.1%, versus 18.7 plus or minus 4.3% for scaffold-only and 12.1 plus or minus 3.8% for empty defects (p less than 0.05). Histology matched the markers: DPSC defects showed organized pulp-like connective tissue, vascular structures and odontoblast-like cells lining dentinal walls, while PDLSC defects showed periodontal ligament-like fiber organization, new cementum and more alveolar bone. VEGF is a headline claim with no number behind it: the Results describe it as “more abundant” in the DPSC group around newly formed vessels, and no H-score, group value or p-value for VEGF appears in the paper.

The gap in the comparison

The title promises a comparison of the two cell types, and the Abstract and Conclusion state that the scaffolds showed “tissue-specific” improvement in pulp and periodontal regeneration “respectively.” The data do not contain that comparison. The DSPP analysis covers the DPSC, scaffold-only and empty groups but never reports a DSPP value for the PDLSC group. The BV/TV analysis covers the PDLSC, scaffold-only and empty groups but never reports a BV/TV value for the DPSC group. Each cell type was measured against controls on a different endpoint, and no statistic in the paper pits DPSC against PDLSC on anything. The “tissue-specificity” conclusion is a qualitative pattern read from two separate single-endpoint results, not a tested difference. Two independent audits of the full text agree on this point and on every number above.

Boundary and what it changes

This is one center’s 8-week rabbit xenograft, n of 6 per group, with human cells in immunocompetent rabbits and no assessment of the xenogeneic immune response the authors themselves flag as a risk; no functional testing, no neural markers, no pulp vitality measurement, one cell dose and one scaffold composition, and no power calculation behind the n. The regenerated tissue is pulp-like and periodontal-like on histology, not demonstrated function. Editorial control is also part of the record: a literal placeholder, “[cite 2-3 relevant papers],” survives in the published Methods section, and the mechanistic discussion of DNA methylation, BMP-Smad and EZH2 cites no data from this study. The strongest honest claim is narrow: in this rabbit model, adding DPSCs or PDLSCs to a collagen-hydroxyapatite scaffold beat an acellular scaffold on two different structural endpoints at 8 weeks. For the pulp and dentin repair program that is a small confirmatory datapoint in a long line of similar preclinical results, and the field assessment at /field/ does not change on it. The study’s own closing sentence, calling for quantitative, longer-term studies before clinical application, is the right frame, and this site adopts it.

Provenance: grounded in the full open-access text of Elbaram et al. (2026), Babcock Univ. Med. J. 9(3):379-388, doi:10.38029/babcockuniv.med.j…v9i3.1848, retrieved from the publisher’s PDF. See /method/.