Effect of dentin conditioners on biomarker release and microhardness of radicular dentin: an in vitro study

AIM: This study investigated the effects of various radicular dentin conditioning agents, maleic acid, citric acid, phosphoric acid, and EDTA, on dentin-derived biomarker release and radicular dentin microhardness for regenerative endodontic applications. MATERIALS AND METHODS: Sixty single-rooted teeth were processed into dentin cylinders and discs and randomly assigned to five groups (n = 12): 7% maleic acid, 10% citric acid, 37% phosphoric acid, 17% EDTA, and phosphate-buffered saline (PBS) as a negative control. Growth factor release (TGF-β, VEGF, BMP-2) was quantified using ELISA after 24 h incubation. Microhardness changes were evaluated in corresponding dentin cylinders sectioned longitudinally. RESULTS: Maleic acid produced the highest release of TGF-β, VEGF, and BMP-2 (p < 0.001), followed by EDTA, citric acid, and phosphoric acid in a biomarker-dependent hierarchy. Microhardness was significantly affected by the conditioning agent (p = 0.004), with EDTA and maleic acid reducing dentin hardness compared with the control, while citric acid and phosphoric acid showed no significant effect. No significant differences were observed among root thirds (p = 0.169). CONCLUSION: Dentin conditioning in regenerative endodontics involves a trade-off between biological activation and preservation of structural integrity. Stronger conditioning agents enhance growth factor release but may compromise dentin hardness. Among the tested agents, citric acid demonstrated the most balanced performance, combining effective biomarker release with minimal effects on dentin microhardness. In contrast, phosphoric acid preserved dentin structure but showed limited biological activity, making it less suitable when regenerative signaling is the primary objective. CLINICAL RELEVANCE: The selection of dentin conditioning agents should not be based solely on their biological signaling potential, as it directly influences the mechanical properties of radicular dentin and may impact regenerative outcomes.