الفهرس 
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Abstract
Summary and Conclusions
The purpose of this study was to compare the antimicrobial effect
of acidic media (gluconic acid and citric acid) and alkaline media
(calcium hydroxide) against Enterococcus faecalis and Candida albicans.
Suspensions of Enterococcus faecalis and Candida albicans were
adjusted to approximately 0.5 McFarland standards. This study consisted
of two parts:
Part I: agar diffusion method, agar plates were swabbed with the
prepared microbial suspensions using sterile swabs. Four sterile filter
paper discs were applied to each plate. Then the tested medicaments and
saline were pipetted onto the paper discs. The plates were maintained at
room temperature for 2- hours and were incubated at 37 ºC for 24- hours.
Then, the diameters of inhibition zones were recorded in millimeters
using transparent ruler for data analysis. The test was repeated for each
material 6-time with each of Enterococcus faecalis and Candida albicans.
Part II: eighty extracted single rooted human teeth were included in
the study. Root lengths were standardized. The root canals were
instrumented using Protaper Universal rotary system to F5. A 2.5%
sodium hypochlorite was used for irrigation in conjunction with 17%
EDTA. The root surfaces were coated with varnish and root apices were
sealed with resin. Each root was placed separately inside Eppenorf tube.
After proper sterilization, paper points were used to confirm sterilization.
The canals were contaminated with the prepared suspensions containing
either Enterococcus faecalis or Candida albicans. The contaminated
roots were incubated for 7- days at 37 ºC. On the fourth day; replenishing
of the microbial suspensions was done, then the tubes were closed again
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until 7- days were completed. After 7- days; 20-μl of Mueller Hinton
broth (MHB) was added to confirm contamination using sterile paper
points. Then the root canals were irrigated with saline and were dried
using sterile paper points. The root canals were divided according to
microorganism contamination. Group I: Enterococcus faecalis, Group II:
Candida albicans. Each group was divided into 4 equal subgroups
according to the tested material. Subgroup A: 10% calcium hydroxide,
subgroup B: 10% citric acid, subgroup C: 5% gluconic acid, subgroup D:
saline (control). The roots were incubated at 37 ºC for 7- days. After the
7- days, the tubes were opened and the medicaments were removed.
Postoperative paper point samples were obtained and plated on agar
plates. The plates were incubated at 37°C for 24-48 hour. The number of
colony forming units of Enterococcus faecalis and Candida albicans
were counted for data analysis and confirmed by Gram stain with light
microscope.
The results of part I of this study showed that for Enterococcus
faecalis, citric acid had the highest statistically significant mean
inhibition zone diameter. This was followed by calcium hydroxide, then
gluconic acid then saline. For Candida albicans, there was no statistically
significant difference between calcium hydroxide and citric acid; both
showed the highest statistically significant mean Candida albicans
inhibition zone diameters. While, both gluconic acid and saline showed
the lowest statistically significant mean Candida albicans inhibition zone
diameters.
The results of part II of this study showed that for both
Enterococcus faecalis and Candida albicans, there was no statistical
significant difference between calcium hydroxide, citric acid and
gluconic acid. While saline showed the statistically significantly lowest
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mean % reduction in Enterococcus faecalis and Candida albicans counts
compared to other groups.
Conclusions:
Within the limitation of this study, it can be concluded that
different intra-canal irrigants and medicaments used in this study exerted
different antimicrobial effect against Enterococcus faecalis and Candida
albicans as follows:
1- A 5% gluconic acid has better antimicrobial effect than 10%
citric acid against Candida albicans.
2- A 10% citric acid is more effective against Enterococcus
faecalis than 5% gluconic acid.
3- A 10% calcium hydroxide is more effective against both
microorganisms.