Primer containing dimethylaminododecyl methacrylate kills bacteria impregnated in human dentin blocks.

Sheng Lin-Gibson,Chen Chen,Michael D Weir,Xue-Dong Zhou,Hockin Hk Xu,Lei Cheng,Nancy J Lin

doi:10.1038/ijos.2016.43

Abstract

Antibacterial dimethylaminododecyl methacrylate (DMADDM) was recently synthesized. The objectives of this study were to: (1) investigate antibacterial activity of DMADDM-containing primer on Streptococcus mutans impregnated into dentin blocks for the first time, and (2) compare the antibacterial efficacy of DMADDM with a previous quaternary ammonium dimethacrylate (QADM). Scotchbond Multi-Purpose (SBMP) bonding agent was used. DMADDM and QADM were mixed into SBMP primer. Six primers were tested: SBMP control primer P, P+2.5% DMADDM, P+5% DMADDM, P+7.5% DMADDM, P+10% DMADDM, and P+10% QADM. S. mutans were impregnated into human dentin blocks, and each primer was applied to dentin to test its ability to kill bacteria in dentinal tubules. Bacteria in dentin were collected via a sonication method, and the colony-forming units (CFU) and inhibition zones were measured. The bacterial inhibition zone of P+10% DMADDM was 10 times that of control primer (P<0.05). CFU in dentin with P+10% DMADDM was reduced by three orders of magnitude, compared with control. DMADDM had a much stronger antibacterial effect than QADM, and antibacterial efficacy increased with increasing DMADDM concentration. Dentin shear bond strengths were similar among all groups (P>0.1). In conclusion, antibacterial DMADDM-containing primer was validated to kill bacteria inside dentin blocks, possessing a much stronger antibacterial potency than the previous QADM. DMADDM-containing bonding agent was effective in eradicating bacteria in dentin, and its efficacy was directly proportional to DMADDM mass fraction. Therefore, DMADDM may be promising for use in bonding agents as well as in other restorative and preventive materials to inhibit bacteria.

Highlights

Dental caries is the destruction of dental hard tissues caused by acidic products from bacterial fermentation of dietary carbohydrates.[1,2]Approximately 200 million tooth cavity restorations were performed annually in the United States, costing about $40 billion per year.[3]
The results showed that adding dimethylaminododecyl methacrylate (DMADDM) and quaternary ammonium dimethacrylate (QADM) into the primer did not adversely affect the dentin bond strength (P40.1)
This study showed that antibacterial primer containing DMADDM was much more effective than QADM in killing bacteria impregnated into dentin blocks

Summary

Introduction

Dental caries is the destruction of dental hard tissues caused by acidic products from bacterial fermentation of dietary carbohydrates.[1,2]Approximately 200 million tooth cavity restorations were performed annually in the United States, costing about $40 billion per year.[3]. The chemical, physical, and mechanical properties of composites have been improved significantly.[4,5,6,7,8,9,10,11] about half of all restorations fail in less than 10 years, with secondary caries as one of the primary reasons.[12,13,14,15] it would be highly desirable to improve the materials to reduce secondary caries and restoration failure.[11,12,13,14,15]

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Discussion

Conclusion