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Introduction: Calcium hydroxide (Ca(OH) 2 ) is the material of choice for pulp therapy. However, Ca(OH) 2 has drawbacks such as toxicity, poor sealing, and tunnel defect formation. Alternative materials have been developed to provide more biocompatible materials with better dentin formation ability. The objective of this study was to evaluate the effect of composites containing gelatin (G), chitosan (CH), tetraethyl orthosilicate (TEOS), and Ca(OH) 2 , namely G-CH-TEOS-Ca (OH) 2 (Extended data) on inflammation of the dental pulp (expression of COX-2, PGP 9.5, TNF-α, and neutrophil number)., Materials and Methods: A total of 16 Wistar rat models of acute pulp injury were prepared and divided into two groups, treatment and control, 8 with each. In the treatment group, we applied a pulp-capping material using G-CH-TEOS-Ca (OH) 2 and Ca(OH) 2 . On the 1 st and 3 rd days, rats were sacrificed. Tissue samples from 4 rats in each group were processed for histological preparation. COX-2, PGP 9.5, and TNF-α were observed using immunohistochemical (IHC) staining, and neutrophil numbers were observed using hematoxylin-eosin staining. Image analysis of COX-2, PGP 9.5, and TNF-α expression was performed using ImageJ software., Results: The results showed a decrease in COX-2 expression, but not significantly while PGP 9.5 and TNF-α expression were significantly higher than those in the control group. Neutrophil numbers were lower in the treatment group than in the control group, but the difference was not statistically significant., Conclusion: The G-CH-TEOS-Ca (OH) 2 composite material may have potential as an exposed pulp medicament by reducing inflammation (COX-2 expression and number of neutrophils) and increasing the regeneration factor (TNF-α expression) and nerve (PGP 9.5 expression)., Competing Interests: No competing interests were disclosed., (Copyright: © 2025 Ghadah Abdulrahman Aq et al.)

A series of photoreactive polymers containing poly(N,N-dimethylacrylamide) and 2-hydroxy-(4-methacryloyloxybenzophenone), P(DMAA-n%MABP-OH), was explored to modify sheet-formed carbonated hydroxyapatite/gelatin (CHA/gelatin) scaffold. Under UV-light illumination, the benzophenones react with any C–H bonds in their vicinity through a C,H-insertion mechanism, enabling PDMAA-based hydrogel formation that is covalently attached to the gelatin. NMR spectroscopy confirmed the chemical structure of P(DMAA-n%MABP-OH) polymers with aimed n = 1, 5, 10, while GPC determined their molecular masses. The benzophenone reactivity under UV-light illumination for 0–240 min. was demonstrated using UV-Vis spectroscopy at 240–400 nm. After immobilization of P(DMAA-n%MABP-OH) onto the CHA/gelatin scaffold, typical FTIR vibration bands of both compounds could be detected on the spectra of the modified scaffolds. SEM images showed that the scaffold is highly porous with approximately 100 µm thickness. P(DMAA-n%MABP-OH) addition led to 2–3 times increase in thickness and 15–19% mass addition. Furthermore, it was shown that chemical (degradation and Ca2+ release profile), physical (4−7 swelling index), mechanical (0.06−0.17 MPa wet tensile strength and 0.2−0.8 MPa elastic modulus), and biological (cell adhesion) properties of the scaffold could be tailored by varying the photocrosslinker content. Cytotoxicity test showed that all studied CHA/gelatin-based scaffolds were nontoxic (>80% cell viability). [ABSTRACT FROM AUTHOR]