Immune and microbial cellular interactions with contemporary and alternative resin-based dental restorative materials.

OBJECTIVES

To compare a non-ester methacrylate-alternative dental resin (ER) with conventional ester-based methacrylate resin (MAR) in terms of (i) susceptibility to degradation by human neutrophils (hN), (ii) influence on hN pro-inflammatory phenotypes, and (iii) modulation of Streptococcus mutans (SM) virulence-gene expression.

METHODS

The ER was formulated with in-house synthesized biostable monomers 3BE and 3TE (50/50 wt%), and MAR with contemporary monomers bisphenol A-glycidyl methacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) (50/50 wt%). Cured resin and constituent monomers were incubated with hN, where biodegradation by-products were quantified by LC-MS, and hN activation using established pro-inflammatory CD markers and flow cytometry. SM biofilms were grown on ER and MAR surfaces in continuous-flow and batch cultures at neutral (pH 7.1) and cariogenic (pH 5.5) conditions, where the virulence of SM biofilms was interpreted by the relative expression of established virulence genes (gftB, gbpB, nlmA, vicK, smu.118c) quantified by qPCR.

RESULTS

Cured MAR specimens and constituent monomers degraded significantly more than ER and constituent monomers in the presence of hN (p < 0.05). hN CD-marker expression did not differ among groups. Under cariogenic, continuous-flow conditions, SM biofilms on MAR up-regulated nlmA and smu.118c relative to ER (p < 0.05). In batch cultures, MAR surfaces induced significant up-regulation of nlmA (both pH 7.1 and 5.5), smu.118c (pH 5.5) and gbpB (pH 5.5), while gtfB was down-regulated at both pH values, compared with ER surfaces.

CONCLUSIONS

The ER demonstrated enhanced biostability against hN-mediated degradation while enabling a low inflammatory state for immune cells, and the potential for favourable interactions with a key cariogenic bacterium SM.

CLINICAL SIGNIFICANCE: These findings support the ER's potential as a more durable and biocompatible alternative to conventional methacrylate-based materials for dental restorations.