Compositional differences in multi-species biofilms formed on various orthodontic adhesives

Area of Science:

• Dental Materials Science
• Microbiology
• Biomaterials Engineering

Background:

• Orthodontic adhesives are crucial for bracket bonding.
• Understanding biofilm formation on these materials is vital for oral health.
• Different adhesive types possess varying surface properties that may influence bacterial adhesion.

Purpose of the Study:

• To investigate multi-species biofilm formation on composite, compomer, and resin-modified glass-ionomer cement (RMGI) with diverse surface characteristics.
• To correlate surface properties like roughness and free energy with bacterial adhesion patterns.

Main Methods:

• Multi-species biofilms (13 bacterial species) were cultivated on composite, compomer, and RMGI surfaces.
• Bacterial quantification (Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, total bacteria) was performed using real-time PCR at days 1 and 4.
• Surface roughness (SR), surface free energy (SFE), and surface texture were analyzed.

Main Results:

• RMGI exhibited higher adhesion for Streptococcus mutans, Streptococcus sobrinus, and Porphyromonas gingivalis compared to other adhesives.
• Total bacterial adhesion did not differ significantly among the tested adhesives.
• Surface roughness of RMGI was significantly higher than composite or compomer, correlating with increased adhesion of specific bacterial species.

Conclusions:

• The rougher surface topography of RMGI, characterized by micro-pores and flaws, is a primary factor promoting the adhesion of Streptococcus mutans, Streptococcus sobrinus, and Porphyromonas gingivalis.
• Surface roughness plays a more significant role than surface free energy in determining bacterial adhesion patterns on these orthodontic materials.