A Novel Dental Sealant Containing Dimethylaminohexadecyl Methacrylate Suppresses the Cariogenic Pathogenicity of Streptococcus mutans Biofilms.

Maria Salem Ibrahim,Ahmed S Ibrahim,Thomas W Oates,Mary Anne S Melo,Nancy J Lin,Franklin R Tay,Hockin H K Xu,Michael D Weir,Abdulrahman A Balhaddad

doi:10.3390/ijms20143491

Abstract

Cariogenic oral biofilms are strongly linked to dental caries around dental sealants. Quaternary ammonium monomers copolymerized with dental resin systems have been increasingly explored for modulation of biofilm growth. Here, we investigated the effect of dimethylaminohexadecyl methacrylate (DMAHDM) on the cariogenic pathogenicity of Streptococcus mutans (S. mutans) biofilms. DMAHDM at 5 mass% was incorporated into a parental formulation containing 20 mass% nanoparticles of amorphous calcium phosphate (NACP). S. mutans biofilms were grown on the formulations, and biofilm inhibition and virulence properties were assessed. The tolerances to acid stress and hydrogen peroxide stress were also evaluated. Our findings suggest that incorporating 5% DMAHDM into 20% NACP-containing sealants (1) imparts a detrimental biological effect on S. mutans by reducing colony-forming unit counts, metabolic activity and exopolysaccharide synthesis; and (2) reduces overall acid production and tolerance to oxygen stress, two major virulence factors of this microorganism. These results provide a perspective on the value of integrating bioactive restorative materials with traditional caries management approaches in clinical practice. Contact-killing strategies via dental materials aiming to prevent or at least reduce high numbers of cariogenic bacteria may be a promising approach to decrease caries in patients at high risk.

Highlights

Dental caries is a biofilm-triggered oral disease with an international pandemic distribution, primarily affecting school-age children [1]
While this study focused on the ability of sealant formulations with 5% dimethylaminohexadecyl methacrylate (DMAHDM) and 20% nanoparticles of amorphous calcium phosphate (NACP) to alter the virulence-related traits of S. mutans, further research on the underlying mechanisms of bacterial/quaternary ammonium interactions is needed to optimize materials and achieve desired outcomes of improved oral health
S. mutans relies on its virulence-related traits to change oral plaque biofilms and promote the development and increase the severity of carious lesions in children

Summary

Introduction

Dental caries is a biofilm-triggered oral disease with an international pandemic distribution, primarily affecting school-age children [1]. The World Health Organization reports that dental caries is the most common oral condition included in the Global Burden of Disease Study [2]. In efforts toward pediatric caries prevention, dental sealants were introduced for application on the occlusal surface. The sealants act as a physical barrier for microorganisms at the pits and fissures of the teeth. Evidence-based clinical recommendations, stated by the American Dental Association and the American Academy of Pediatric Dentistry, support sealants as a practical approach in preventing and arresting pit-and-fissure occlusal caries lesions [4]. Sealants are a widely used preventive approach against occlusal carious lesions, the failure rate is high. Longitudinal data [5,6] show reasons for failure related to bacterial colonization underneath the sealed fissures with the progressive demineralization and development of cavitation

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