Three-Dimensional Substrates for Exposure of Dental Pulp Cells to Bacteria or Lipopolysaccharide: A Systematic Review

This systematic review aimed to evaluate whether the use of 3D substrates improved cell behaviour compared to 2D substrates for the study of exposure between human dental pulp cells (HDPCs) and bacteria/lipopolysaccharides (LPS). Articles studying the interaction between HDPCs and bacteria/LPS in 3D substrates between January 2000 and May 2025 were included from 4 databases (MEDLINE, Scopus, Web of Science and Embase) following a registered protocol (Prospective Register of Systematic Reviews CRD42024512080) and as per Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Grey literature was searched in Google Scholar. Out of 2754 articles, 21 were eligible for full-text review, and finally, 10 articles were included. Cell viability was the primary outcome, whereas cell proliferation, expression of mineralisation, inflammatory markers and antimicrobial activity were the secondary outcomes. The Quality Assessment Tool for In Vitro Studies was used for quality assessment. Among the 10 included studies, only 1 study assessed cell-live bacteria interactions, while the remaining 9 examined cell-LPS exposure within 3D substrates. Cell viability was found to be consistently improved in the 3D substrates despite the LPS/bacteria challenge. Odontogenic differentiation and mineralization potential were consistently improved compared to 2D substrates. 3D substrates modified with antimicrobial, anti-inflammatory and bioactive molecules provided additional advantages. The integration of biomaterials, HDPCs and bacteria/LPS provides promising outcomes mimicking the pulp 3D microenvironment.