Irreversible hydrocolloids: a comparison of antimicrobial efficacy.

The surface antimicrobial efficacy of four irreversible hydrocolloid materials against two common oral bacteria, Lactobacillus and Streptococcus mutans, was evaluated. Twelve reversible hydrocolloid (agar) plates for each bacteria were used. Five wells, 1 cm in diameter by 5 ml in depth, were punched into each plate that contained a known concentration of bacteria. An equal-sized but different type of irreversible hydrocolloid plug was placed into each of four wells. The fifth (center) well contained chlorhexidine (Peridex) as a positive control agent. Results indicated that the irreversible hydrocolloids Coe Hydrophilic Gel (CHG) with chlorhexidine and Jeltrate Plus with quaternary ammonium were both as effective as the positive control agent in reducing surface growth of the bacteria studied. The use of antimicrobial irreversible hydrocolloids thus may aid in reducing operatory to laboratory cross-contamination.