Summary:
Microorganisms, usually from the dental caries, are the main
sources of diseases in dental pulp (root canals) and periapical
region. Facultative bacteria and fungi have been identified in
therapy resistant persistent endodontic infection. The objectives
of this study was to evaluate the antimicrobial efficacy of Mineral
Tri Oxide Aggregate (MTA) against therapy resistant endodontic
microorganisms. The efficacy of MTA was also compared with
that of calcium hydroxide. Six standard bacterial stains were
used: Staphylococcus aureus, Pseudomonas aeruginosa,
Escherichia coli, bacillus subtilis, Candida albicans and
Enterococcus faecalis. The agar diffusion method on Muller-
Hilton media was employed. The plates containing media were
inoculated with the specified bacterial suspensions. Two
standard holes were prepared on each microorganism inoculated
plate with a copper puncher and one hole was completely filled
with MTA & the other with Ca (OH)2 . The plates were then
kept at environmental temperature for one hour to ensure
prediffusion and then incubated at 37 0C for 24 hours. After 24
hours, the diameters of inhibition zones were measured. Tests
were replicated for thirty times for each sample and mean values
were taken. Zone of inhibition as measured for MTA and Ca
(OH)2 were statistically analyzed with Student’s t-Test and Post
Hoc Games Howell Test and were presented as mean ± SD to
compare of efficacy of MTA and calcium hydroxide on different
microorganisms. Both MTA and Ca(OH)2 were found to produce
zone of inhibition against Staphylococcus aureus (ATCC
25923), Pseudomonas aeruginosa (ATCC 27853), , Bacillus
subtilis (BTCC 17 ), and Candida albicans (BTCC 493). MTA
showed highest activity against S. aureus and lowest activity
against P. aeruginosa which was similar to the activity range of
Ca (OH) 2 against the mentioned organisms. But both of them
failed to produce any activity against E. coli and. E. faecalis.
MTA was found to produce a lower efficacy than Ca (OH) 2
while comparing the zone of inhibition between them and
statistically it was significant. Mineral Tri Oxide Aggregate
(MTA) showed antimicrobial efficacy against some therapy
resistant microorganisms but it did not show antimicrobial
efficacy against Escherichia coli and Enterococcus faecalis.
MTA was found to produce a lower antimicrobial efficacy than
Ca (OH)2.
Keywords: Mineral Tri Oxide Aggregate (MTA), Calcium
hydroxide, antimicrobial efficacy.
(J Banagladesh Coll Phys Surg 2015; 33: 140-145)