SEOUL, South Korea: According to the American Association of Orthodontists , more than five million people seek orthodontic treatments each year in the US and Canada alone. Therapy includes fixed orthodontic appliances and aligners, whose materials are prone to bacterial contamination. However, researchers from Yonsei and Kyung Hee universities in Seoul have now reported that they have developed a film that reduces bacterial growth on dental appliances. Bacteria frequently build up on clear aligners or retainers, which also suffer from poor abrasion resistance.

The researchers set out to develop a simple and affordable coating to combat this issue. They drew inspiration from super-hydrophilic antibacterial coatings on other medical devices in order to see if they could develop something similar for plastic appliances in the oral environment.The researchers layered films on a polymer sheet modified with glycol (PETG).

This layered film created a super-hydrophilic surface that prevented bacteria from adhering, resulting in a 75 per cent reduction in bacterial growth between coated PETG and the bare material. The coated plastic was also stronger and more durable, even when tested with artificial saliva and various acidic solutions.

The study, titled “A polysaccharide-based antibacterial coating with improved durability for clear overlay appliances”, was published online in ACS Applied Materials and Interfaces on 4 May 2018 ahead of inclusion in an issue.