Candida albicans (C. albicans), along with other pathogenic microorganisms, is the most commonly isolated root canal fungus in endodontic practice [1–3]. These pathogens are able to colonize dentinal tubules at a depth of 150 mcm and form biolayers (biofilms) even in relatively clean and sealed root canals and is resistant endodontic treatments [4, 5].
In recent years, new combinations of medicinal substances have been developed and proposed for clinical use aimed at eliminating pathogenic yeast fungi in the root and dentinal tubules.
With regard to intratubular pathogens Enterococcus faecalis, Klebsiella pneumoniae and Candida albicans, laboratory data revealed a rather high antibacterial activity of a combination of 2% chlorhexidine and silver nanoparticles (AgNP)[6, 7].
Many researchers note that the inclusion of antimycotic substances such as ketoconazole and fluconazole in the composition of root filling materials enhances the antimicrobial effect without changing their physical properties [8, 9]. Experimental clinical trials using substances based on medicinal plants also have great prospects. In root canals ,QmiX and guava leaf extract, mixtures of extracts of guava leaves and apple cashew [10], a mixture of methanol extract of Azadirachta indica (Neem), Mimusops elengi (Bakul) and chlohexidine [11], has a pronounced inhibitory effect on these microorganisms.
The inclusion of antimycotic drugs and probiotics in the composition of the root paste is a fairly promising direction in antibacterial endodontic therapy[13–15].
Based on this, the purpose of the study was to evaluate some of the physicochemical properties of therapeutic pastes for temporary filling of root canals based on zinc oxide with eugenol and antimycotic additives (nystatin, fluconazole, "Narine" - Lactobacillus acidophilus Er-2 strain 317). /402).
Materials and methods
The physicochemical properties of a healing paste based on zinc oxide with eugenol and antimycotic additives (nystatin, fluconazole and "Narine" - Lactobacillus acidophilus Er-2 strain 317/402) were studied for temporary filling of roots canals
"Narine" (Lactobacillus acidophilus n.v. Strain Er2 317/402) was chosen as a probiotic considering its properties to suppress opportunistic microorganisms. Probiotic-"Narine"(based on a monoculture of lactic acid bacteria Lactobacillus acidophilus) is produced from natural pasteurized skimmed cow's milk by fermentation. "Narine" normalizes intestinal microbial biocyanosis, restores the anaerobic flora of bifidobacilli and lactobacilli, inhibits the growth of opportunistic microorganisms, as well as the production of lectolin, lactocylacticin, lactobacilli [16, 17].
Methods of experiments are identical to those of described in SOST P51094* (ISO 3107-88) and SAUS (State–All-Union-Standard)/Р 51744 − 2001**(corresponds to the international standards ISO 9917-91 and ISO 9917-2-98).
In this case, we used the following compositions and preparations nystatin - ZnO2 (2:4), fluconazole + ZnO2 (2:4), lactobacillus acidophilicus + ZnO2 (2:4), lactobacillus acidophilicus + eugenol + ZnO2 (1:1:4), nystatin + eugenol + ZnO2 (1:1:4), fluconazole + eugenol + ZnO2 (1:1:4).
The following physical-chemical properties of the mentioned combinations of pastes are investigated:
Definition of the pure time of hardening.
The experiment was carried out according to [**], on the base of visual estimation of the degree of lowering the flat-tip needle onto the surface of the sample. The metallic form, thermostated by temperature 23 ± 10C was put on aluminum foil and filled it with mixed paste up to the upper surface of the form. In 5 minutes after mixing the form filled with paste was put on a metallic block (not less than 8x75x100 mm in size) together with the aluminum foil and thermostated by 37 ± 10C. In 180 minutes after finishing mixing the indenter’s needle was carefully lowered vertically onto the surface of the sample and left in this position for 5 s. In the experiments was used a 200 ± 5 g in mass indenter with a flat-tip cylindrical needle at the top. The butt of the needle is flat and perpendicular to the longitudinal axis of the needle, the diameter of the needle is 1.0 ± 0.1 mm and the length – 5 mm.
When defining the pure time of hardening the observations were carried out starting with submerging the needle 60 minutes before the rough time of the paste hardening with the interval of 30 minutes. The time was fixed as a pure time of hardening from the moment of mixing the past until the disappearance of the imprint of the needle on the paste surface. The experiment was repeated on the three samples and the pure time of hardening was correspondingly (Table 1).
Table 1
Pure time of paste hardening with antimycotic components.
Sample№ | Variant, antimycotic supplement | Hardeningtimeof the sample, min. | Puretimeof hardening, min. |
1 | Narine | 450 | 480 |
2 | 450 |
3 | 480 |
4 | Nistatin | 390 | 390 |
5 | 390 |
6 | 390 |
7 | Fluconazole | 630 | 660 |
8 | 600 |
9 | 660 |
Definition of the surface structure of the hardened paste.
With the help of the electronic microscope DS-300 (Telsa-Chekh Republic) we investigated the surface structure of the studied combination of healing temporary root pastes.
Disintegration definition (solubility in distilled water and in isotonic solution).
The experiments were conducted according to [*], on the base of gravimetric dimensions of the sample mass. The samples were made with the help of forms composed of enlarged rings made of stainless steel of 1.5 mm in height and 20 mm in internal diameter, placed in a pattern or fixing plate (Fig. 1). Two samples were made for each of the parallel experiments on all the three variants of pastes. The form was located on a polyethylene or acetylene-cellulose pellicle under which was a glass plate. A suspended wire was inserted through the opening of the enlarged ring (error ± 0.001g) so as not less than 10mm was on the ring. The ring was a bit plentifully filled with paste. It was covered with the other glass plate putting under its polyethylene or acenthyle cellulose pellicle and pressed the plates firmly. In 3 minutes after the beginning of mixing the form was placed into the thermostat (37 ± 10C) with the plates. Taking into consideration the samples’ hardening time for each paste (see Table 1), the plates with the samples were taken out of the thermostat, the filling disc together with the wire was carefully separated from the covering ring. Two samples were put into a bottle with a wide neck. Not less than 50ml distilled water (or isotonic solution) was immediately poured into the bottle. After closing the cover firmly, the bottle was put into the thermostat for 24 hours by temperature 37 ± 10C. The disc was taken out, the surface of the sample was washed with a little amount of distilled water and dried with filter paper. Then the sample was put into exicator for 24 hours. The mass weighing was repeated until obtaining the permanent mass with error ± 0.001 g. Disintegration (solubility) – D was defined by formula (in % by mass) D=(m1-m2) x100/m1 Where m1- sample mass, g; m2- final mass,g .
Definition of acidity degree (pH).
The following powder mixtures for pastes (weight ratio) were prepared: zinc oxide – 2.5 part and antimycotic component − 1.0 part. pH suspensions of the powder mixture were defined with the help of pocket electronic pH-meter “CHECKER” HI 98103 (producer – HANNA). The device was chipped beforehand with buffer solution with ph-7.01. Water suspensions of the powder mixtures were prepared with different content of a dried substance. For this were prepared three samples for each experimented supplement Weights were added into 5ml distilled water correspondingly: 0.1 g (sample1), 0.3 g (sample2) and 0.5g (sample 3) ± 0.01 of the mixture, shook up, maintained the suspension for 1–2 minutes and measured.