Biocompatibility and acid resistance of preformed crowns in children

Abstract Objectives: To investigate the in vitro biocompatibility of human gingival fibroblasts (HGFs) with PPC, and resistance to acid exposure at levels that simulate the oral environment. Materials and Methods: This laboratory study investigated primary HGFs viability, metabolic activity, cytotoxicity, and apoptotic events on preformed metal crown (PMC) discs, composite resin (CR)-coated wells, and monolithic ZR fragments at 24, 48, and 72 h using the ApoTox-Glo Triplex assay. The PPCs were also immersed in 0.1% lactic acid, 0.2% phosphoric acid, or 10% citric acid for 7 days at 37 o C to reproduce conditions associated with dietary intake or gastric reflux. Samples were then subject to inductively coupled plasma optical emission spectrometry (ICP-OES) to quantitate the release of ions. Results: The viability of HGFs on stainless steel and CR significantly declined at 48 and 72 h, representing potential cytotoxicity (p < 0.05). Cytotoxicity of HGFs was also higher for stainless steel and ZR compared to control (p < 0.05). PMCs and ZR crowns gave minimal ion release. Meanwhile, significant quantities of metallic ions, including copper (Cu), iron (Fe), nickel (Ni), and zinc (Zn), were present in eluates from veneered-preformed metal crowns (V-PMCs). Conclusions: As PPCs can be exposed to highly acidic environments for many years, thus the release of metallic ions from V-PMCs should form the further investigated in future studies Clinical Relevance: The study showed that paediatric restorative materials are mildly cytotoxic to HGFs depending on the oral environment.