IADR Abstract Archives
Determining Growth of Streptococcus Mutans on Thermoplastic Orthodontic Aligners
Objectives: Streptococcus mutans has a key role in developing caries and is one of the early colonizers of in plaque biofilm formation. The purpose of this project was to test the growth and ability of S.mutans biofilm adhesion on thermoplastic orthodontic clear aligners. This in vitro study assessed S.mutans biofilm formation on clear aligners and quantifiable colony forming units (CFUs) on the aligners. Therefore, the preliminary goal of this project was to determine the dilution factor of S.mutans in Brain Heart Infusion (BHI) broth to obtain quantifiable colonies. The secondary goal was to see whether the aligners were sterile.
Methods: Stock solution was prepared by reconstituting S.mutans. The ideal solution was found by using serial dilutions of BHI broth (Research Products International, 5.5mL) with stock solution (ATCC 25175, 0.5mL) to achieve 12-fold dilutions. Ten dilutions were prepared and incubated and plated on sheep blood agar plates (Thermo Scientific Blood Agar, 37°C, 24-48h) to see if there were an acceptable CFUs (less than 300 CFUs). In order to determine the sterility of the aligners, the packaged pouch of the aligners was opened and carefully massaged to directly submerge them into BHI broth (200mL) and incubated (37°C, 24-48h). These plated samples were sent to a laboratory (Charles River Research Animal Diagnostic Services) and used the Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) test to identify the organisms.
Results: The ideal serial dilution of S.mutans was determined to be 1x127, with 82 CFUs. The qualitative observations suggested bacterial growth. The Charles River Research Animal Diagnostic Services identified the microorganisms to be of the Bacillus genus, possibly one of the following: B.altitudinis, B.pumilus, or B.safensis. The aligners were then treated with ultraviolet (UV) light overnight to examine if it would affect its growth. The qualitative results supported the idea that the Bacillus organism was resistant to UV.
Conclusions: The results of the ideal serial dilution suggest a factor for the colonies that grew on the aligners suggesting that the aligners do not come completely sterilized and that S.mutans does bind to the aligners.
Methods: Stock solution was prepared by reconstituting S.mutans. The ideal solution was found by using serial dilutions of BHI broth (Research Products International, 5.5mL) with stock solution (ATCC 25175, 0.5mL) to achieve 12-fold dilutions. Ten dilutions were prepared and incubated and plated on sheep blood agar plates (Thermo Scientific Blood Agar, 37°C, 24-48h) to see if there were an acceptable CFUs (less than 300 CFUs). In order to determine the sterility of the aligners, the packaged pouch of the aligners was opened and carefully massaged to directly submerge them into BHI broth (200mL) and incubated (37°C, 24-48h). These plated samples were sent to a laboratory (Charles River Research Animal Diagnostic Services) and used the Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) test to identify the organisms.
Results: The ideal serial dilution of S.mutans was determined to be 1x127, with 82 CFUs. The qualitative observations suggested bacterial growth. The Charles River Research Animal Diagnostic Services identified the microorganisms to be of the Bacillus genus, possibly one of the following: B.altitudinis, B.pumilus, or B.safensis. The aligners were then treated with ultraviolet (UV) light overnight to examine if it would affect its growth. The qualitative results supported the idea that the Bacillus organism was resistant to UV.
Conclusions: The results of the ideal serial dilution suggest a factor for the colonies that grew on the aligners suggesting that the aligners do not come completely sterilized and that S.mutans does bind to the aligners.
