The effects of dyadic combinations of endodontic medicaments on microbial growth inhibition

In recent years dyadic combinations of endodontic medicaments have been used increasingly in clinical pediatric dentistry with little regard to the possibility of pharmacological antagonism of the components. In this investigation, a microbial growth inhibition assay was used to determine changes in antimicrobial activity in dyadic mixtures of endodontic medicaments. The combinations assayed were Ledermix (corticosteroid-antibiotic) and Calyxl (calcium hydroxide), Ledermix and Kri (iodoform), Kri and Calyxl, and formocresol and eugenol. All these compounds have antibacterial activity when used individually. In the dyadic combinations assayed, results showed that adding calcium hydroxide to another antibiotic preparation has deleterious effects on growth inhibition, and combining any two antimicrobial medicaments produces no additive or synergistic effects. It is concluded that it may be clinically advantageous to use endodontic medicaments in the dyadic combinations shown in this investigation.