In vitro susceptibility of oral Candida albicans strains to different pH levels and calcium hydroxide saturated aqueous solution

Abstract

Candida albicans is present in the oral cavity and in the whole digestive tract of humans and other animals, being frequently related to endodontic treatment failure. The present study determined the incidence of C. albicans in the oral cavity and the susceptibility of isolates to different pH values and saturated calcium hydroxide aqueous solution at pH 12.5. Sixty-five patients attending the Endodontic Clinic at the Sagrado Coração University participated in the study. The collected samples were cultivated in selective media for C. albicans and the isolates were tested in terms of resistance to both alkaline pH and saturated aqueous solution of calcium hydroxide. In relation to time variables, yeast viability was assessed by the Sabouraud's agar culture and fluorescein diacetate and ethidium bromide fluorescent staining method. Results from the different pHs and experimental times, including those from different techniques measuring fungal viability, were compared using the chi-square and Fisher's exact tests (α=0.05). The yeasts became completely inviable after 48 h of contact with the calcium hydroxide solution. On the other hand, when exposed to the alkaline culture broth, the yeasts were found to be viable at pHs 9.5 and 10.5 for up to 7 days. In conclusion, C. albicans can only be completely inhibited by direct contact with saturated calcium hydroxide aqueous solution after 48 h of exposure.

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

“…Similar results were reported by Weckwerth et al, who studied the susceptibility of 30 strains of oral C. albicans isolated from clinical specimens [74]. A decline in Candida growth was observed at 6, 12, and 24 h, with full inhibition of growth after 48 h of direct contact with an aqueous CH solution [74]. However, it seems evident that the resistance of C. albicans to CH in vivo is higher because the microorganisms are able to invade dentinal tubules and remain protected from the action of alkaline endodontic medications because of the buffering effect of dentin [66,75,76].…”

“…Only 6 of 16 strains survived after 3 h but were killed after 6 h of incubation [ 73 ]. Similar results were reported by Weckwerth et al, who studied the susceptibility of 30 strains of oral C. albicans isolated from clinical specimens [ 74 ]. A decline in Candida growth was observed at 6, 12, and 24 h, with full inhibition of growth after 48 h of direct contact with an aqueous CH solution [ 74 ].…”

Effects of probiotic bacteria on Candida presence and IgA anti-Candida in the oral cavity of elderly

“…The identification of analyses showed that C. albicans was the most prevalent species before and after the probiotic use. Its predominance in the oral cavity has been demonstrated (6,12,13). Several non-albicans species were also isolated, a phenomenon identified in long-term antibiotic users, immunossupressed and chronic pathologies patients (14)(15)(16).…”

Candida albicans, from endodontic point of view

“…Also, probiotic organisms of Lactobacillus and Bifidobacterium species are suggested to be effective in preventing the growth of E. faecalis and C. albicans in vitro [43] . This microorganism can only be completely inhibited by direct contact with a saturated aqueous calcium hydroxide solution after 48 hours of exposure [44] . The antibacterial photodynamic therapy and calcium hydroxide therapy showed the same antimicrobial efficacy on E. faecalis and C. albicans [45] .…”