S. mutans gene-modification and antibacterial resin composite as dual strategy to suppress biofilm acid production and inhibit caries

Hong Chen; Bin Zhang; Michael D Weir; Negar Homayounfar; Guadalupe Garcia Fay; Frederico Martinho; Lei Lei; Yuxing Bai; Tao Hu; Hockin H K Xu

doi:10.1016/j.jdent.2020.103278

S. mutans gene-modification and antibacterial resin composite as dual strategy to suppress biofilm acid production and inhibit caries

J Dent. 2020 Feb:93:103278. doi: 10.1016/j.jdent.2020.103278. Epub 2020 Jan 13.

Authors

Affiliations

¹ State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China; Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA.
² State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
³ Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA.
⁴ School of Stomatology, Capital Medical University, Beijing, China. Electronic address: byuxing@263.net.
⁵ State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China. Electronic address: hutao@scu.edu.cn.
⁶ Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA; Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA. Electronic address: hxu@umaryland.edu.

PMID: 31945398
DOI: 10.1016/j.jdent.2020.103278

Abstract

Objective: Composite restorations are increasingly popular, but recurrent caries is a main reason for composite restoration failures. The objectives of this study were to investigate a dual strategy of combining rnc gene-deletion for Streptococcus mutans (S. mutans) with antibacterial dimethylaminohexadecyl methacrylate (DMAHDM) composite, and determine the effects of rnc gene-deletion alone, DMAHDM composite alone, and rnc-deletion plus DMAHDM composite, on biofilm growth and lactic acid production.

Methods: Parent S. mutans (UA159, ATCC 700610) and rnc-deleted S. mutans were used. DMAHDM was incorporated into a composite at mass fractions of 0%, 1.5%, and 3%. Gene expressions for biofilm formation and drug resistance were analyzed using quantitative real-time polymerase chain reaction (qRT-PCR). Biofilms were grown on composite surfaces for 2 days. Live/dead, biomass, polysaccharide, metabolic activity (MTT), colony-forming units (CFU) and lactic acid production of biofilms were evaluated.

Results: Compared to the parent S. mutans, the rnc-deletion technique yielded significantly less biofilm biomass, polysaccharides, metabolic activity, CFU, and lactic acid for biofilms grown on control composite (p < 0.05). With no gene modification, the biofilm CFU was decreased by 5-6 logs at 3% DMAHDM, when compared to control composite group. The dual strategy of combining rnc-deletion with 3% DMAHDM composite achieved the strongest biofilm-inhibition, with the greatest reduction in CFU by 8 logs. The combination of rnc-deletion with 3% DMAHDM composite decreased the biofilm lactic acid production by 95% (p < 0.05).

Conclusions: The dual strategy of rnc-deletion plus DMAHDM composite produced synergistic effects and achieved the strongest biofilm-inhibition. This method has great potential to inhibit dental caries and is promising to reduce secondary caries and protect tooth structures.

Keywords: Acid production; Biofilm growth; Dental composite; Dimethylaminohexadecyl methacrylate; Recurrent caries; rnc gene modification.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Bacterial Agents*
Biofilms*
Composite Resins
Dental Caries*
Humans
Methacrylates
Resins, Synthetic*
Streptococcus mutans / genetics*

Substances

Anti-Bacterial Agents
Composite Resins
Methacrylates
Resins, Synthetic