A novel methacrylate derivative polymer that resists bacterial cell-mediated biodegradation

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Dental materials require resistance to biodegradation, particularly from oral bacteria like Streptococcus mutans.
• Existing methacrylate-based polymers, such as ethylene glycol dimethacrylate (EGDMA), can degrade over time, compromising mechanical integrity.
• The placement of ester linkages within the polymer structure may influence susceptibility to bacterial hydrolysis.

Purpose of the Study:

• To synthesize and evaluate a novel ethylene glycol ethyl methacrylate (EGEMA) with external ester linkages.
• To compare the biodegradation resistance and mechanical properties of EGEMA against EGDMA when exposed to Streptococcus mutans.
• To investigate the impact of ester linkage position (external vs. internal) on polymer stability in a biological environment.

Main Methods:

• EGEMA and EGDMA polymer discs were synthesized using photopolymerization.
• Discs were incubated with Streptococcus mutans in Todd Hewitt Yeast + Glucose media for up to 9 weeks.
• Physical and mechanical properties, including degree of conversion, diametral tensile stress (DTS), hardness, surface wettability, material loss, fracture toughness, and water sorption, were assessed.

Main Results:

• EGEMA exhibited significantly higher diametral tensile stress (DTS) retention and lower material loss after 9 weeks of S. mutans exposure compared to EGDMA.
• EGEMA showed less surface degradation, cracking, and reduced water sorption than EGDMA.
• While EGDMA had higher initial hardness, EGEMA demonstrated superior stability and resistance to bacterial degradation, attributed to its external ester linkage design.

Conclusions:

• The novel EGEMA polymer with external ester linkages offers enhanced resistance to biodegradation by Streptococcus mutans.
• External ester linkage placement in methacrylate polymers provides a significant advantage in maintaining physical and mechanical properties under bacterial challenge.
• EGEMA represents a promising candidate for dental restorative materials requiring improved durability and resistance to oral environments.