Evaluation of Antibacterial Efficacy of Two Commercially Available Probiotics as Intracanal Medicament against Enterococcus faecalis: An In Vitro Study.

AIM: This study was performed to evaluate the antibacterial efficacy of two commercially available probiotics (BIFILAC and VSL 3) as intracanal medicament against Enterococcus faecalis in endodontic therapy. MATERIALS AND METHODS: Microorganisms from commercially available probiotics (BIFILAC and VSL 3) were extracted via the manufacturer's recommendations and mixed by weight. About 30 microliters were then placed on sterile discs. The pathogenic test organism was E. faecalis set to a 1 McFarland standard challenge. A two-probiotic disc template on blood agar plates was inoculated with E. faecalis and incubated at 37°C for 48 hours and 1 week respectively. Phase-1 of the study was conducted by a disc diffusion assay test to evaluate zones of inhibition (ZOI) in millimeters (mm). Phase-2 was conducted by mixing 9 mL of 30% poloxamer 407 and MRS broth in a test tube, together with the two probiotic mixtures and E. faecalis, set at a 2 McFarland standard. Serial dilutions up to 108 were done and the mixture was placed inside root canals and incubated at 37ºC for 36 hours and evaluated for colony-forming unit (CFU)/mL counts. RESULTS: The results of phase-1 showed that probiotics Lactobacillus rhamnosus and Bifidobacterium species are effective in fighting against E. faecalis with the acceptable zone of inhibition. The results of phase-2 showed that both the probiotics are effective against E. faecalis with a reduction in the number of CFU after probiotic usage. CONCLUSION: Commercially available probiotics can be used effectively as an intracanal medicament to fight against E. faecalis, Poloxamer 407 is a promising vehicle for delivering probiotics inside the root canal system. Further in vitro and in vivo studies are needed to determine the full potential of "Bacteriotherapy" with an application of probiotics. CLINICAL SIGNIFICANCE: If probiotics are proved to be an effective intracanal medicament against E.faecalis they can be used as an alternative to calcium hydroxide as intracanal medicament with no side effects to the host.

Comparative Assessment of Qmix as Endodontic Irrigant on Reversal of Bond Strength in Teeth Subjected to Irradiation: An Scanning Electron Microscope Study.

AIM: The aim of this current study was to compare and evaluate the reversal efficacy of Qmix and chitosan-based irrigation materials quantitatively through the assessment of the push-out bond strength of bioceramic sealer employing universal testing machine and to qualitatively analyze the sealer/dentin interface by scanning electron microscope (SEM) in the teeth subjected to fractioned radiation. MATERIALS AND METHODS: Ninety single-rooted straight human maxillary central incisors were randomly divided into six groups (n = 15) where in three groups comprise Chitosan, Qmix, and EDTA/sodium hypochlorite which were not exposed to irradiation while other three groups were challenged with irradiation protocols. Root canals were prepared with ProTaper universal system and all the samples were irrigated according to the final irrigation protocols and obturated with bioceramic sealers. Dentin slices were prepared with 1 mm thickness from each root third for the estimation of bond strength of sealers to dentin. Qualitative assessment of the sealer-dentin interface was done by scanning electron microscopy. Bond strength data were scrutinized by independent t-test and failure modes using the Chi-square test. RESULTS: Significantly lower bond strength (p <0.05) was recorded after irradiation compared with nonirradiated group. To quantify the results irrigation protocols, Qmix had highest bond strength followed by chitosan and EDTA/sodium hypochlorite group irrespective of irradiation status. Bond strength values reduced after irradiation in all root thirds irrespective of the irrigation materials. Scanning electron microscope images revealed traces of repair process for Qmix-based irrigation materials than the chitosan-based materials for both irradiated and nonirradiated specimens. CONCLUSION: All the irrigation materials employed in this study had good bond strength. The specimen irrigated with Qmix had comparatively higher bond strength than the chitosan-based materials. The teeth subjected to irradiation challenge were associated with a decrease in the push-out bond strength of sealers to intraradicular dentin with formation of more gaps and fewer tags at the sealer/dentin interface. CLINICAL SIGNIFICANCE: Selection of ideal irrigation protocols still remains a challenge for the clinical practitioners, and this study explored the utilization of novel materials used for irrigation, especially in the teeth subjected to radiation.

Comparative Assessment of Novel Collagen Cross-linking Agents on Push-out Bond Strength of Two Different Sealers: An In Vitro Study.

AIM: To assess the push-out bond strength and tubular penetration of resin-based and bioceramic sealers after employing two collagen cross-linking agents, namely, cashew nut shell liquid (CNSL) and epigallocatechin-3-gallate (EGCG) on sodium hypochlorite treated root canal dentin. MATERIALS AND METHODS: Fifty human permanent mandibular premolars selected were decoronated at CEJ, this was followed by cleaning and shaping protocols, root canals were enlarged up to 20 sizes with 6% taper and were randomly divided into the following 5 groups with 10 samples each based on the cross-linking agent and the sealer: • Group I: Irrigation with saline (control). • Group II: Irrigation with cashew nut shell liquid followed by bioceramic sealer obturation. • Group III: Irrigation with cashew nut shell liquid followed by resin-based sealer obturation. • Group IV: Irrigation with EGCG followed by bioceramic sealer obturation. • Group V: Irrigation with EGCG followed by resin-based sealer obturation. Five specimens in each group were evaluated for push-out bond strength with the universal testing machine while the remaining five specimens in each group were evaluated for depth of sealer penetration by a scanning electron microscope (SEM). The data was recorded, tabulated, and statistically analyzed. RESULTS: The push-out bond strength was found to be maximum in the apical region in all the five groups followed by the middle third and coronal region. The maximum push-out bond strength was seen in group II followed by groups III and IV, and least in group V. The mean depth of tubular penetration of sealers was found to be effective in the coronal portion followed by the middle third while the apical third region showed the least depth penetration of sealers into the tubules. The maximum penetration of sealers was revealed in group V followed by groups III and IV, and least in group II. CONCLUSION: Within the limitations of this study, it can be concluded that push-out bond strength was found to the maximum in specimens irrigated with cashew nut shell liquid and obturated with bioceramic sealer. The maximum push-out bond strength was seen in the apical third of all root canals followed by the middle and coronal region. The scanning microscopic analysis revealed maximum mean tubular penetration in the coronal portion followed by the middle third and apical third. A greater penetration was seen in specimens irrigated with EGCG and obturated with hybrid sealer. CLINICAL SIGNIFICANCE: Selection of sealers plays a pivotal role in the success of endodontic therapy. Leakage-related issues can compromise the bond strength enhancing the bond strength can be achieved through the addition of cross-linking agents.

Novel Management of Hypersensitive Dentin Using Propolis-based Herbal Desensitizing Agents: An In Vitro Scanning Electron Microscopic Study.

AIM: The objective of this in vitro study was to assess the efficacy of novel propolis-based varnish against the two conventional varnishes on quantitative and qualitative assessments of occlusion of dentin tubules and resistance to erosive and abrasive wears employing scanning electron microscope (SEM). METHODS: Thirty human premolars free from caries extracted due to orthodontic reasons were included in the study. Experimental group was done based on treatment received and divided into three groups. Group A: ClinProXT Varnish (n = 10), Group B: MI Varnish (n = 10), and Group C: Propolis Varnish (n = 10) were applied. Teeth were cleaned and decoronation of crown was done with dentin disks. Dentin specimens of dimension 4 × 4 × 2 mm were prepared and subjected to finishing and polishing. The sample specimens were submersed in EDTA solution for a period of five minutes to open up the dentinal tubules. This was followed by treatment with varnishes and subjection to acidic-abrasive challenge. The specimens were analyzed with an image analyzer connected to SEM for the verification of the number of opened dentin tubules. The parameter assessed in SEM includes size, topography and surface characteristics of dentinal tubule were assessed. The obliteration potential of dentinal tubules was assessed with SEM images. Additionally, the dentin surface loss and resistance to acidic and abrasive wear were also evaluated with SEM. Data were analyzed with two-way analysis of variance (ANOVA) with post hoc Tukey's test. RESULTS: MI Varnish caused higher obliteration of dentin tubules followed by ClinproXT Varnish. Propolis Varnish showed the least obliteration of dentinal tubules among tested experimental groups. After acidic-abrasive challenge, Propolis Varnish was found to be more efficient with less material loss among the experimental groups tested. There was an insignificant difference among the MI Varnish and ClinProXT Varnish groups. CONCLUSION: Simulation of hypersensitive lesions mimicking the clinical scenario was a challenging task in this in vitro study. All varnishes tested in the study had good efficacy in the management of dentin hypersensitivity (DH). Propolis-based varnish had good resistance to material loss after subjection to acidic-abrasive challenge among the tested materials. The casein phosphopeptide (CPP)-amorphous calcium phosphate (ACP)-based MI Varnish had good efficacy to obliterate the dentinal tubules among the tested materials. It was prudent to select the varnishes with good long-term efficacy to survive in the clinical scenario which still remains a challenging task for the clinicians. CLINICAL SIGNIFICANCE: The stability of the varnish plays a vital role in maintenance of its long-term efficacy. The chemical nature along with the ability of the material to interact with the substrate plays a major role in management of DH.

Comparison of Cyclic Fatigue Resistance of Novel TruNatomy Files with Conventional Endodontic Files: An In Vitro SEM Study.

AIM AND OBJECTIVE: To compare and analyze the cyclic fatigue resistance of novel TruNatomy files against the conventionally used rotary files and reciprocating files in a simulated canal system with curvatures in the middle, apical portions root, and S-shaped canal employing scanning electron microscopy. MATERIALS AND METHODS: Endodontic files tested in the study include ProTaper, HyFlex EDM, Reciproc blue, and TruNatomy files operated in a simulated root canal system. A total of 96 files were employed in this study. They were categorized into four groups. Group 1 employed 24 TruNatomy files, group 2 employed 24 ProTaper gold files, group 3 employed 24 HyFlex EDM files, and group 4 employed 24 Reciproc blue files. All the groups employed eight files each under three subgroups namely A, B, and C representing middle, apical, and double curvatures, respectively. Artificial grooves were incorporated in the stainless steel blocks having three different curvatures. All the file systems were operated with a torque-controlled electric motor. The files were engaged in the artificial canal until the occurrence of fracture. The time required for the fracture was noted. Length of fractured tip was measured using the digital Vernier caliper. The number of cycles of failure (NCF) was calculated. The fractured parts were subjected to scanning electron microscope to analyze the mode of fracture. RESULTS: TruNatomy files had the highest mean NCF values of 588.01 in middle curvature, 1,321 in apical curvature, and 642.5 in S-shaped curvature HyFlex EDM and Reciproc blue file system exhibited comparable cyclic fatigue resistance among them. ProTaper gold file system exhibited least mean NCF values of 158.13 in the middle, 196.5 in the apical curvature, and 116.88 in the S-shaped canal system. Middle portion fractured first than the apical curvature. The mean length of fractured segments was found to be insignificant among the experimental study groups tested. CONCLUSION: All the file systems employed in the study had good cyclic fatigue resistance while TruNatomy files had the highest cyclic fatigue resistance while HyFlex EDM and Reciproc blue had comparable fatigue resistance. ProTaper gold file system had the least fatigue resistance at different radius of curvature in the simulated canal system in the apical and middle portions and S-shaped root canal. CLINICAL SIGNIFICANCE: The selection of file systems in cleaning and shaping protocols is an enigma to the endodontics. This in vitro study explored the selection protocols for the execution of root canal preparation. Heat treatment of nickel-titanium (NiTi) endodontic files had improved the cyclic fatigue résistance significantly enhancing the clinical life of file systems.

Comparative Evaluation of the Antioxidant Effects of Oregano on Bleached Enamel Using Energy-dispersive X-ray Spectroscopy Analysis: An In Vitro Study.

AIM AND OBJECTIVE: The aim of this study was to evaluate the efficacy of novel antioxidant oregano against conventional antioxidants sodium ascorbate and green tea through comparison of the baseline weight percentage (wt%) of minerals prior to bleaching with values after bleaching protocols and antioxidant application by employing energy-dispersive X-ray spectroscopy analysis (EDAX). MATERIALS AND METHODS: Thirty noncarious, freshly extracted human permanent maxillary incisors without any visible defects were selected as samples. They were divided into three groups (n = 10) based on the antioxidant treatment received as follows: group I-10% sodium ascorbate solution, group II-10% green tea solution, and group III-5% oregano solution. 35% hydrogen peroxide was employed for bleaching. The wt% of teeth was calculated at three time intervals. The initial wt% was calculated prior to the bleaching procedure. The second one was calculated after subjecting to bleaching protocols, and final one was calculated after antioxidant treatment using EDAX. RESULTS: There was a statistically significant decrease in the calcium/phosphorus ratio for the bleached samples in comparison with the sound enamel. There was a comparable and significant increase in the calcium/phosphorus ratio values after application of the antioxidant with insignificant difference among the antioxidants evaluated in the study. CONCLUSION: Treatment with antioxidants helped in the reversal of mineral loss, which occurred due to the bleaching procedure while the efficacy of 10% oregano on reversal of the calcium and phosphorus ratio was found to comparable to that of 10% sodium ascorbate and green tea. CLINICAL SIGNIFICANCE: Application of antioxidants after bleaching reduced the time delay in performing the adhesive procedures without compromising their clinical efficacy.

Comparative Evaluation of the Efficacy of Novel Root Canal Irrigation Techniques on Reduction of Enterococcus faecalis Count: An In Vitro Study.

AIM AND OBJECTIVE: To compare the effectiveness of three irrigation systems, namely, Endovac system, Max I probe, and Navitip FX, in reduction of Enterococcus faecalis population from the root canal using agar diffusion method. MATERIALS AND METHODS: Sixty extracted intact human permanent maxillary anterior teeth were selected for this study. In group I, root canals were irrigated using brush covered 30-gauge NaviTipFX. Ultradent in group II root canals was irrigated using brush covered 30-gauge Max-I-Probe Dentsply. In group III, root canals were irrigated using Endoactivator, Dentsply. In group IV, root canal was irrigated by using the Endovac system Sybronendo. The steps followed in the study include preparation of specimen, contamination of the samples followed by conduction of testing procedures with implementation of appropriate irrigation protocols, and sampling procedures. RESULTS: Data were subjected to statistical analysis to interpret the significant differences among various irrigation systems. One-way analysis of variance, Post hoc Tukey tests were used for statistical analysis in the present study. Among the experimental groups, group IV showed statistically significant difference in reduction of E. faecalis. There were no statistical differences between them in reduction of E. faecalis in group I and group II compared and represented in Tables 1 and 2. CONCLUSION: All four irrigation delivery systems have been found to be effective in the reduction of E. faecalis. Endovac showed comparable efficacy in reduction of colony-forming units to that of other delivery systems used in the study. The result has to be validated with in vivo studies and clinical trials of larger sample size. CLINICAL SIGNIFICANCE: Selection of appropriate irrigation system capable of disinfection of canal complexities in apical third with less adverse effects is essential for good clinical success of endodontic treatment.