In vitro investigation of the effect of substrate type and plasma treatment onthe surface coating with periodontal ECM and Streptococcus mutans biofilmformation

Background and Objective: In order to study microbial biofilms, it is important to form a suitablebiofilm in laboratory conditions. Therefore, the type of substrate and its surface characteristics, such assurface free energy, morphology, and hydrophilicity, are the most important factors that must beconsidered for cell attachment and substrate coverage. Currently, plasma treatment is known as one of thesuitable methods to change and improve the surface characteristics of the polymer substrate, with nodamage to its entirety. Plasma can improve the adhesion of the coating by creating different polarfunctional groups on the surface of the polymer substrate and increasing its wettability and hydrophilicproperties. Therefore, the aim of this study is to investigate the effect of plasma treatment and the type ofpolymethyl methacrylate and glass substrate on the amount of coverage with sheep periodontal ECM andthe formation of Streptococcus mutans biofilm.Methods: In this research, polymethyl methacrylate and glass plates were used as substrates. Thenatmospheric air plasma treatment was applied at a distance of ۳ mm from the polymer surface for ۲۰seconds. In the following, its effect on the coverage of two substrates with extracellular matrix preparedfrom sheep periodontal was studied and compared with the Aniline Blue colorimetric method. Thecoating of the surfaces was created by evaporation of the extracellular matrix suspension using a vacuumoven on the desired surfaces. The tryptic broth culture medium was enriched with half percentage of yeastextract for the growth and biofilm formation of Streptococcus mutans bacteria was used. The amount ofbiofilm formed on the test surfaces after incubation for ۴۸ hours at ۳۷°C was measured using acolorimetric method based on light absorption at ۵۷۰ nm.Results: The results showed that the treatment with plasma had a significant effect on the increase of theamount of the attached periodontal extracellular matrix on both polymethyl methacrylate and glasssurfaces. Also, the treatment with plasma indicated a high effect on the amount of formed biofilm on thecoated surfaces which has been received plasma treatment at first. However, plasma treatment did nothave any significant effect on improving the bacteria adhesion to uncoated surfaces, in any type ofsubstrates, and also it alone did not help the development of biofilm formation.Conclusion: According to the obtained findings, it can be stated that treatment with plasma under thementioned conditions can have a positive effect on increasing the amount of surface coverage with theextracellular matrix of the periodontal and help the formation and development of Streptococcus mutansbiofilm under laboratory conditions.

Keywords:

Streptococcus mutans , Dental biofilm , Plasma treatment , Protein coating , Polymethylmethacrylate surface