Effect of Colonization of Microorganisms on Orthodontic Bonding Materials: An SEM Study

Abstract

Demineralization on the tooth surface around orthodontic brackets occurs, with microorganisms being the principal causative factors. This in - vitro study was conducted to evaluate and compare growth of Streptococcus mutans, Staphylococcus aureus and Pseudomonas on three orthodontic bonding materials and the changes in surface characteristics of the bonding materials.

120 standardised pellets were divided into 2 groups as Control group (30 pellets) and Study group (90 pellets), which were subdlvided into 3 control subgroups and 9 study subgroups of 10 pellets each. The pellets were weighed and inoculated with respective bacteria, the culture media being artificial saliva and nutrient broth. Control group was not inoculated with any bacteria. The sample was incubated at 37° C for 7 days. Study was carried out under, total aseptic conditions. The pellets were re-weighed after the growth of bacteria and weight differential percentage was calculated. Intergroup comparisons were done using t-test. The surface was examined under scanning electron microscope (SEM) to see for the surface changes.

Streptococcus mutans showed maximum growth on all the bonding materials tested, while Pseudomonas showed the least growth. Rely-A-Bond showed the least growth of all the bacteria except for the Staphylococci which showed least growth oil Cure-On-Touch. SEM pictures revealed the greatest surface damage was on the Enlight material, mainly caused by Streptococcus mutans.

The orthodontic bonding adhesive should be chosen cautiously ta avoid dental caries and in-between-treatment bracket failures.