In situ antibiofilm effect of glass-ionomer cement containing dimethylaminododecyl methacrylate

Objective: The aim of this study was to investigate antibiofilm effects of a recently developed glass ionomer cement (GIC) containing dimethylaminododecyl methacrylate (DMADDM) under oral conditions.

Methods: Biofilms were allowed to form in situ on GIC specimens (n=216) which contained DMADDM (1.1wt.% or 2.2wt.%). Samples without DMADDM served as control (n=108). GIC specimens were fixed on custom made splints and exposed to the oral cavity in six healthy volunteers for 24, 48 and 72h, respectively. Biofilm viability and coverage were analyzed by fluorescence microscopy (FM) and evaluated by red/green ratios and an established scoring system. Bacterial morphology and biofilm accumulation were determined by scanning electron microscopy (SEM). Additionally, material properties as surface charge density of quaternary ammonium groups, surface roughness and DMADDM release were recorded.

Results: FM results showed a higher ratio (24h: 0%: 0.5, 1.1%: 1.2, 2.2%: 2.5) of red/green fluorescence on GIC samples containing DMADDM. Biofilm coverage and viability scores were significantly reduced (24h: q1/median/q3 for: 0%: 3/4/5, 1.1%: 2/3/3, 2.2%: 1/2/2) on DMADDM containing samples compared to controls after 24h as well as 48 and 72h in situ (p<0.05). While surface charge density of quaternary ammonium groups and DMADDM release increased with the DMADDM concentration, surface roughness was lowest on specimens containing 2.2wt.% DMADDM.

Significance: An in situ dental biofilm model was used to evaluate the novel GIC containing DMADDM. This material strongly inhibited biofilms in situ and is promising to prevent bacterial colonization on the surface of restorations.