Antimicrobial Efficacy of Four Calcium Hydroxide Formulations and Chlorhexidine Gel using Agar Diffusion Model
P Ravishanker, C Subba Rao
agar diffusion test, calcium hydroxide, chlorhexidine, e. faecalis
P Ravishanker, C Subba Rao. Antimicrobial Efficacy of Four Calcium Hydroxide Formulations and Chlorhexidine Gel using Agar Diffusion Model. The Internet Journal of Dental Science. 2008 Volume 8 Number 1.
The main aim of endodontic treatment is to eliminate microorganisms and their byproducts from the root canal system as well as to prevent re-infection. Though cleaning and shaping plays an important role, it is not capable of thoroughly eliminating microorganisms, particularly anaerobic bacteria 1 . Occasionally, treatment-resistant species, especially facultative anaerobe
Investigators have noted that bacteria in instrumented, unfilled canals can multiply and reach their pretreatment numbers in 2 to 4 days. Hence, it is generally believed that residual microorganisms can further be reduced by dressing the canal with a medicament between successive treatment sessions 2, 3 . Calcium hydroxide (Ca(OH)2) is commonly used for this purpose; however, specific microbes, such as
Chlorhexidine (CHX) has a wide-spectrum antimicrobial activity against gram-positive and gram-negative microorganisms, bacterial spores, lipophilic viruses and yeasts 7 . As a root canal irrigant and intracanal medicament, CHX has an antibacterial efficacy comparable to that of sodium hypochlorite (NaOCl) 8, 9 . In addition, it is also effective against strains resistant to Calcium hydroxide 10 .
The aim of the present
Materials and Methods
Agar diffusion test
Group I - 99.9% Ca(OH)2 powder(Calcium hydroxide extra pure, DPI, India) mixed with saline – 1gram/ml
Group II - 99.9% Ca(OH)2 powder(Calcium hydroxide extra pure, DPI, India) with 1% chlorhexidine solution – 1gram/ml
Group III (Vitapex, Neodental International Inc, Japan)) - 30% Ca(OH)2 paste with 22.4% silicon base
Group IV (Apexcal, Ivoclar Vivadent, Liechtenstein) - 25% Ca(OH)2 in a mixture of water glycerin, polyethylene glycol and other supplementary agents.
Group V (Hexigel, ICPA, India) - 1% Chlorhexidine Gel
A sample from each group was placed in the outer five wells. A total of six such inoculated agar plates with medicaments were prepared.
The agar plates were incubated at 37 o C for 24 hrs in an incubator. The diameters of bacterial inhibition zones around each well were measured and recorded (Fig. 1).
The 5mm well widths were subtracted from the measurements, which were then divided by a factor of 2 to obtain the average zones of inhibition on one side of the wells.
Statistical analysis using One- way ANOVA followed by using multiple Tukey HSD method revealed significant difference (P<0.05) between the groups (Table 1).
1% chlorhexidine gel showed significant inhibition of bacterial growth compared with other medicaments. Vitapex showed least inhibition of bacterial growth. No significant difference was found between Ca(OH)2 combined with saline, Calcium hydroxide combined with 1% chlorhexidine solution and Apexcal.
Apexcal with 25% Ca(OH)2 showed no significant difference between 99.9% Calcium hydroxide mixed with saline and 1% chlorhexidine solution. Safavi and Nakayama (2000) stated that thick preparations of Ca(OH)2 should have the same ionic concentration as thin preparations of Calcium hydroxide. There may be other factors for antibacterial effect as vehicle for mixing and consistency of the mix. Calcium hydroxide mixed with 1% chlorhexidine has the same antimicrobial effect as when mixed with saline. Chlorhexidine has a positive charge and Calcium hydroxide has a negative charge. Therefore, the pH effect of Calcium hydroxide is possibly decreased when mixed with chlorhexidine. The same interaction could have decreased the effectiveness of chlorhexidine in this formulation.
Our study showed that CHX had good efficacy against
Under the conditions of the study, 1% Chlorhexidine Gluconate gel showed better antibacterial efficacy against