• Xu, Hockin H. K.
• Oates, Thomas W.
• Alsahafi, Rashed
• Weir, Michael D.
• Wang, Xiaohong
• Alhussein, A.
• Filemban, Hanan
• Mitwalli, Heba
• Hack, Gary D.
• Sun, Jirun

Abstract

<jats:p>Objectives: Current dental resins exhibit polymerization shrinkage causing microleakage, which has the potential to cause recurrent caries. Our objectives were to create and characterize low-shrinkage-stress (LSS) composites with dimethylaminododecyl methacrylate (DMADDM) as an antibacterial agent to combat recurrent caries. Methods: Triethylene glycol divinylbenzyl ether and urethane dimethacrylate were used to reduce shrinkage stress. DMADDM was incorporated at different mass fractions (0%, 1.5%, 3%, and 5%). Flexural strength, elastic modulus, degree of conversion, polymerization stress, and antimicrobial activity were assessed. Results: The composite with 5% DMADDM demonstrated higher flexural strength than the commercial group (p &lt; 0.05). The addition of DMADDM in BisGMA-TEGDMA resin and LSS resin achieved clinically acceptable degrees of conversion. However, LSS composites exhibited much lower polymerization shrinkage stress than BisGMA-TEGDMA composite groups (p &lt; 0.05). The addition of 3% and 5% DMADDM showed a 6-log reduction in Streptococcus mutans (S. mutans) biofilm CFUs compared to commercial control (p &lt; 0.001). Biofilm biomass and lactic acid were also substantially decreased via DMADDM (p &lt; 0.05). Conclusions: The novel LSS dental composite containing 3% DMADDM demonstrated potent antibacterial action against S. mutans biofilms and much lower polymerization shrinkage-stress, while maintaining excellent mechanical characteristics. The new composite is promising for dental applications to prevent secondary caries and increase restoration longevity.</jats:p>

Topics

• impedance spectroscopy
• strength
• composite
• flexural strength
• resin
• laser sintering