In-vivo evaluation of the contamination of Super Slick elastomeric rings by Streptococcus mutans in orthodontic patients

Abstract

Introduction: We investigated in vivo the contamination by Streptococcus mutans of Super Slick elastomeric rings (TP Orthodontics, LaPorte, Ind), manufactured with Metafasix technology (TP Orthodontics), using microbial culture and scanning electron microscopy (SEM).

Methods: Twenty patients undergoing fixed orthodontic appliance therapy were selected. Super Slick elastomeric rings (n = 160) were tied to brackets on the right maxillary premolars or molars and left mandibular premolars or molars. Conventional elastomeric rings (n = 160) were tied to brackets on the contralateral premolars or molars with the same split-mouth design. After a 15-day intraoral period, 75 elastomeric rings of each type were retrieved, submitted to microbiologic processing, and cultured in bacitracin sucrose broth-selective enrichment broth culture media. The number of S mutans colonies or biofilms on the surface of the electrometric rings was counted by using a stereomicroscope. Data were analyzed statistically with the Wilcoxon nonparametric test at the 5% significance level. Four representative rings of each type were chosen for SEM analysis.

Results: Statistical analysis by the Wilcoxon nonparametric test showed that the Super Slick elastomeric rings had statistically significant greater S mutans contamination than the conventional elastomeric rings (P <.0001). No formation of S mutans colonies or biofilms was observed in the elastomeric rings removed directly from their original packages. SEM micrographs showed fissures on the surface of Super Slick elastomeric rings. No fissures were found on conventional elastomeric rings. When the microbiologic culture was positive, S mutans bacterial biofilm was observed on both types of ligatures.

Conclusions: There was no clinical evidence that Super Slick elastomeric rings are effective in reducing bacterial biofilm formation on their surfaces, and a recommendation for their use in orthodontic therapy for that purpose is not justifiable.