Microbial contamination of "as received" and "clinic exposed" orthodontic materials

Our objective was to determine whether components of fixed orthodontic appliances as received from the manufacturers and after exposure to the clinical environment are free from microbial contamination before clinical use. A pilot molecular microbiologic laboratory study was undertaken at a dental hospital in the United Kingdom.

A range of orthodontic materials "as received" from the manufacturers and materials "exposed" to the clinical environment were studied for bacterial contamination. After growth on blood-rich media, cultured bacteria were identified by 16S rDNA polymerase chain reaction amplification and sequence phylogeny.

Bacteria were isolated from "as received" bands, archwires, and impression trays, but the level of contamination was low (0.5 × 10(1) to 1.825 × 10(2) CFU/mL(-1)). Various bacterial species were isolated from "clinic exposed" bands, archwires, impression trays, coil springs, and elastomeric modules, but the level of contamination was low (0.5 × 10(1) to 8.0 × 10(1) CFU/mL(-1)). The most commonly identified bacterial species was Staphylococcus epidermidis, followed by Kocuria, Moraxella, and Micrococcus species.

New materials "as received" from the manufacturers and those exposed to the clinical environment are not free from bacterial contamination before use in patients, but this contamination is low considering the potential for aerosol and operator contamination and could be considered insignificant. Further studies would be required to determine the level of risk that this poses.