The antimicrobial effects of zinc oxide-calcium hydroxide mixture fillers: determining the ideal mixture ratio

Abstract

Background and Objectives: Although zinc oxide (ZO)-calcium hydroxide (CaOH) mixtures have been successful regard- ing their absorption rate compatibility with dissolving primary teeth, no study has been conducted on the appropriate mixture ratio to obtain effective antibacterial properties. In this study, we compared antibacterial activity of CaOH-ZO pastes using different mixture ratios sagainst Enterococcus faecalis as an important bacterium in root canal treatment failure.
 Materials and Methods: Seven types of pastes were prepared in our laboratory. The first group included one gram of ZO+eu- genol, second group included one gram of CaOH+distilled water, third group included 0.5gram ZO+0.5gram CaOH+distilled water (1:1), forth group included 0.75gramCaOH+0.25gramZO+distilled water (3:1), the fifth group included 0.33gram of CaOH+0.66gram of ZO+distilled water (1:2), the sixth group included 0.75gram of ZO+0.25 CaOH+distilled water (3:1), the seventh group included 0.66 gram CaOH+0.33 gram ZO+distilled water (2:1), and the final group included one gram of gelatin+distilled water (as the control group). These pastes were compared regarding their antibacterial effects against Enterococcus faecalis using agar diffusion and microdilution methods.
 Results: Except for the control group, all prepared pastes showed antibacterial properties. Order of minimum inhibitory concentration for pastes were as followed: CaOH-ZO (1:3)=CaOH-ZO (1:2)>CaOH-ZO (1:1)>CaOH-ZO (3:1)=CaOH-ZO (2:1)>CaOH=ZO-eugenol. Order of minimum bactericidal concentration, which shows a weaker bactericidal effect, accord- ing to type of paste, were as followed: CaOH-ZO (1:3)>CaOH-ZO mixture (1:2)>CaOH-ZO mixture (1:1)>CaOH-ZO mix- ture (3:1)=CaOH-ZO (2:1)>CaOH=ZO-eugenol. Only CaOH-ZO (1:3) and CaOH-ZO (1:2), showed significantly weaker MICs and MBCs (p < 0.001).
 Conclusion: Considering the limitations of an in-vitro study, in terms of anti-bacterial effects against Enterococcus faecalis, CaOH-ZO mixture (2:1) is equivalent to ZO-eugenol as the most commonly used material in polypectomy of primary teeth.

How Adding Chlorhexidine or Metallic Nanoparticles Affects the Antimicrobial Performance of Calcium Hydroxide Paste as an Intracanal Medication: An In Vitro Study

“…More recently, Meto et al reported a similar C. albicans MIC for copper mixed with CH (125 mg/L) [ 55 ]. Nozari et al reported that they did not observe any antimicrobial effect by zinc oxide on E. faecalis [ 56 ]. Conflicting results have also been reported with the same metals for other oral bacteria, including Streptococcus mutans [ 57 ].…”

Organic Eluates Derived from Intermediate Restorative Dental Materials

“…Barium found on ACTIVA TM and SDR™ surfaces is usually associated with the existence of the radiopacifiying filler agent BaO [65]. In terms of Vitrebond TM , the identified zinc has also been reported by other researchers [64], and its bacterial properties have also been studied comprehensively [66]. The large content of lanthanum for Ketac TM Bond can be attributed to its frequent incorporation in the powder constituents of glass-ionomer cements for an opaqueness increase against rays [67] and was also measured by other researchers [68].…”

Antibacterial Activity of Calcium Hydroxide and Zinc Oxide Combined with Several Solutions against Enterococcus faecalis Growth

“…21 According to Nozari et al, the combination of CaOH and ZnO, especially when associated with CHX, provides a powerful antimicrobial effect against E. faecalis during root canal treatments. 22 Evans et al discovered that E. faecalis becomes susceptible to the combination of CaOH and chlorhexidine when examining the mechanism of resistance to CaOH in bovine dentin. Because of its method of action, CHX takes just a short time to exert an antibacterial effect on E. faecalis.…”