Faecalis In Root Canals Research Articles

Evaluation of Presence of Enterococcus faecalis in Root Canals of Deciduous Molars with Necrotic Pulp by Agar Culture and Polymerase Chain Reaction.

To assess the presence of Enterococcus faecalis in root canals of deciduous molars with necrotic pulp by agar culture and polymerase chain reaction (PCR) assay. This is an experimental study, where a total of 120 endodontic samples were taken from deciduous molars with necrotic pulps. The presence of Enterococcus faecalis was assessed by culture, using Enterococcus confirmatory agar, and by PCR assay. Statistical analysis of the results was performed using McNemar's test. The presence of Enterococcus faecalis was detected in 20 samples (16.67% of total) by microbial culture and in 45 samples (37.5% of total) by PCR assay, with a statistically significant difference between the two methods (p < 0.001). Microbial culture and PCR both detect Enterococcus faecalis, with the latter detecting an additional 25 positive samples. In this study, PCR assay was significantly more sensitive than agar culture method in detecting the presence of Enterococcus faecalis in root canals of deciduous molars with necrotic pulp, that is, 37.5% of all samples. Importance of presence of Enterococcus faecalis in necrotic pulps of deciduous teeth, as it is primarily responsible for failure of endodontic treatment, thus helping clinicians to advocate the use of local drug delivery in primary teeth endodontics and also aids clinicians in choosing the most effective intracanal medication. Nalawade TM, Bhat KG, Kale AD, et al. Evaluation of Presence of Enterococcus faecalis in Root Canals of Deciduous Molars with Necrotic Pulp by Agar Culture and Polymerase Chain Reaction. Int J Clin Pediatr Dent 2023;16(6):816-819.

In vitro effects of Er: YAG laser-activated photodynamic therapy on Enterococcus faecalis in root canal treatment

ObjectivePhotodynamic therapy (PDT) plays an important role for root canal disinfection. Nevertheless, the effect of photosensitizers penetrating dentin tubules is limited, which ultimately impedes the disinfection effect of PDT. The study implements an Er: YAG laser to activate methylene blue, the photosensitizer, to determine the bactericidal impact of PDT on Enterococcus faecalis in vitro root canals. MethodsWe obtained 53 single root canal teeth with intact roots, standardized the root to 9 mm. The root canals were prepared using ProTaper rotary files. Subsequently, the teeth were sterilized, and Enterococcus faecalis was cultured for 3 weeks in vitro using brain heart infusion (BHI). The model of Enterococcus faecalis root canal infection of teeth was constructed by observing Enterococcus faecalis through electron microscope scanning. The teeth were randomly allocated to five treatment groups (n = 10): control, NaOCl, NaOCl + Er: YAG, PDT, and PDT + Er: YAG. Following treatment, the number of colony forming units (CFU)/ml was assessed for each group. Statistical analysis was conducted using one-way ANOVA, with post-hoc analysis using Tukey's test for multiple comparisons. ResultsThe colony counts in the remaining groups were significantly lower compared to the control group (P<0.001). Using PDT alone had the least impact on reducing colonies, while using PDT and Er: YAG laser together resulted in a significant reduction in colony counts (P<0.001). There was no significant difference in colony counts reduction between the NaOCl + Er: YAG group and the PDT + Er: YAG group (P = 1.000). ConclusionsThe combination of Er: YAG laser and PDT significantly enhanced the bactericidal efficacy of PDT against Enterococcus faecalis in root canals. It had a similar impact on eliminating Enterococcus faecalis when compared to the effect of using Er: YAG laser and NaOCl.

The presence of Enterococcus faecalis in saliva as a risk factor for endodontic infection.

The aim of the present study was to investigate and correlate the prevalence of Enterococcus faecalis in saliva and in root canals with different pulpal and periapical conditions. Sixty-seven patients were divided into five groups based on pulpaland periapical tissue status: healthy vital teeth (HVT, n=7), healthy treated teeth without lesion (HTT, n=9), irreversible pulpitis (IP, n=13), necrosis (N, n=18), and post-treatment apical periodontitis (PTAP, n=20). Saliva, rubber dam, sterilitycontrol and pre-treatment root canal samples were collected and microbiologically processed by culture method. The phylogenetic relationship of E. faecalis isolates collected from root canals and saliva were investigated by whole genome sequencing. Fisher's exact test was used to correlate the presence of E. faecalis in root canals or saliva with clinical and/or radiographic findings. Linear/logistic regression analyses were performed to establish the relationship between the presence of E. faecalis in root canals, saliva, and the status of periapical tissues. E. faecalis was found in 18 root canal and saliva samples. E. faecalis root canal isolates were recovered with the highest frequency from post-treatment apical periodontitis. The occurrence of E. faecalis in saliva was strongly associated with its detection in the root canals (P < 0.001). The pretreatment presence of E. faecalis in root canals was associated with significantly higher odds of having periapical lesions (OR=11.03; 95% CI, 1.27-95.70; p < 0.05). Saliva and root canal isolates from the same patient were highly correlated at the phylogenetic level (Jaccard index >0.95). This pilot study confirms the role of E. faecalis in developing peri-radicular lesions in secondary endodontic infections and suggests that saliva could be the main source of infection. Further studies are needed to investigate the exact origin of this bacteria and its true role in the pathogenesis of secondary/persistent endodontic infections.

In vitro antibacterial effects of photodynamic therapy against Enterococcus faecalis in root canals of deciduous teeth

ObjectiveThis study aimed at evaluating the in vitro antibacterial efficacy of photodynamic therapy (PDT) on planktonic E. faecalis and its biofilm in the root canal of infected deciduous teeth.MethodsForty root canals of maxillary deciduous anterior teeth were enlarged up to #35 K-file and inoculated with E. faecalis for 21 days. The root canals were randomly assigned into four groups (n = 10): The normal saline group (control), 1% NaClO group, PDT group, and the 1% NaClO + PDT group. Paper point samples were obtained at baseline (S1) and after treatment (S2). The colony-forming units (CFU) were counted, and the bacterial growth rate calculated. From each subgroup, 5 samples were randomly selected after treatment and a scanning laser confocal microscope (CLSM) used to determine the distribution of dead / living bacteria on the biofilm surface of each subgroup. A scanning electron microscope (SEM) was used to observe bacterial morphologies in the root canal walls of the remaining 5 samples in each subgroup. The Kruskal–Wallis test and Dunn test with boferroni adjustment were used to analyze the effect of the different treatment techniques on the E. faecalis in root canals.ResultsCompared to the saline group, PDT significantly reduced bacterial counts in the root canal (p < 0.05). The CFU counts were lowest (p < 0.05) in the 1% NaClO and in 1% NaClO + PDT groups. The rate of bacterial death on the surface of the biofilm in the PDT group was significantly increased after treatment (p < 0.05), and the rate of bacterial death was highest in 1%NaClO group and 1%NaClO + PDT group (p < 0.05).ConclusionPDT has an antibacterial activity against E. faecalis in the root canal of deciduous teeth. Its activity against planktonic E. faecalis is better than the activity on the intact biofilm. The antibacterial activity of PDT on E. faecalis in root canals of deciduous teeth is lower compared to that of 1% NaClO.

Comparative effects of SWEEPS technique and antimicrobial photodynamic therapy by using curcumin and nano-curcumin on Enterococcus faecalis biofilm in root canal treatment

ObjectivesThis study aimed to compare the antimicrobial effects of the shock wave enhanced emission photoacoustic streaming (SWEEPS) technique and Antimicrobial photodynamic therapy (aPDT) with curcumin and nano-curcumin photosensitizers on Enterococcus faecalis (E. faecalis) biofilm in root canals of extracted teeth. Materials and methodsThis experimental study was conducted on extracted single-rooted human teeth. The teeth were decoronated at the cementoenamel junction, the root canals were instrumented with BioRace system, and their apices were sealed. Smear layer was removed, and the teeth were autoclave-sterilized. E. faecalis strains were cultured in sterile brain heart infusion (BHI) and a bacterial suspension with 0.5 McFarland standard concentration was prepared. The root canals were inoculated with the bacterial suspension and incubated at 37 °C for 4 weeks. The teeth were then divided into 12 groups (curcumin, nano-curcumin, curcumin + LED, nano-curcumin + LED, curcumin + SWEEPS, nano-curcumin + SWEEPS, curcumin + LED + SWEEPS, nano-curcumin + LED + SWEEPS, SWEEPS, positive control and negative control). The number of colony forming units (CFUs) was counted and analyzed by one-way ANOVA and Tukey's test. ResultsA significant difference was noted in colony count among the groups (P<0.001). LED alone had the lowest and nano-curcumin + LED + SWEEPS had the highest root canal cleaning efficacy. SWEEPS along with curcumin, nano-curcumin, and LED significantly decreased the bacterial count compared with other groups (P<0.05). ConclusionApplication of the SWEEPS technique with curcumin and nano-curcumin as photosensitizer activated by LED in aPDT improved the reduction of E. faecalis in root canals.

Antimicrobial efficacy of photosensitized nanoparticles, diode laser, conventional, and sonic irrigation systems against enterococcus faecalis in root canals – An in vitro study

Aim: This study aims to evaluate and compare the antimicrobial effect of Photosensitized Nanoparticles, Diode Laser (DL), and Conventional and Sonic Irrigation Systems against Enterococcus faecalis in root canals – An in vitro Study.Materials and Methods: The root canals of 104 extracted human single-rooted teeth were prepared, and E. faecalis was incubated in the root canals for 1 week. The teeth were randomly divided into four experimental groups and one control group (n = 20): No treatment was done, sodium hypochloride (NaOCl) group (n = 20): Canals irrigated with5 ml of 2.5% NaOCl for 60 s, NaOCl and Endoactivator group (n = 20): Canals irrigated with 5 ml of 2.5% NaOCl for 60 s followed by activation of NaOCl with Endoactivator for 30 s, NaOCl and 910 nm DL group (n = 20): (1 W 5 times for 5 s) canals irrigation with5 ml of 2.5% NaOCl for 60 s followed by Photodynamic Therapy (PDT) with 910 nm DL, silver nanoparticles (AgNPs)/Indocyanine green (ICG)/DL group (n = 20): DL modified PDT with 5 min of irrigation with 5 mL AgNPs (100 ppm)/ICG/910 nm DL (200 mW, 30 s). A reduction in colony count was assessed by counting colony-forming units by Digital Colony Counter.Results: Significant reductions were noted in E. faecalis colony counts in all groups (P < 0.05). The greatest reduction in colony count (99.93%) was noted in the NaOCl and DL group followed by NaOCl and Endoactivator group; however, the differences in this respect between the AN/ICG/DL group and NaOCl group were not significant (P > 0.05).Conclusions: NaOCl and 910 nm DL were more successful in reducing the number of E. faecalis colony counts followed by NaOCl and Endoactivator group but it can also be concluded that PDT with ICG, an 910 nm DL, and AgNPs has the potential to be used as an adjunct for disinfection of the root canal system.

A Comparison of One Shape and ProTaper Next Rotary Systems for Elimination of Enterococcus Faecalis from Root Canal: Microbiological and SEM Evaluation

Incomplete removal of micro- organisms from infected root canals is a common cause of failed endodontic treatment. The difficulty in eradication of Enterococcus faecalis from root canals plays an essential role in pathogenesis of persistent pulpal and periradicular infections. The aim of the present study was to compare the reduction of Enterococcus faecalis in root canals by mechanical instrumentation using two rotary systems (One Shape and ProTaper Next) and Hand K-file instrumentation by using microbiological and Scanning Electron Microscopy (SEM) evaluation. Fifty one freshly extracted mandibular premolars with a single root were collected. After pre-instrumentation sampling, they were divided into three groups, Group A, Group B and Group C in which biomechanical preparation was done using Hand K-File, OneShape and Protaper Next respectively. Reduction in pre- instrumentation and post- instrumentation values of Enterococcus faecalis were analysed using microbiological and SEM evaluation. Statistical analysis by paired ‘t’ test and p value showed that there was highly statistical significant difference in CFU count reduction between the pre-instrumentation and post-instrumentation values in all the groups (p&lt;0.001). Statistical analysis by Kruskal-Wallis Test and Mann-Whitney Test showed that at 1mm and 3mm level, Group A (Hand K-File) scored significantly higher value followed by Group B (OneShape Apical) and Group C (ProTaper Next). The most effective instrumentation technique in eliminating Enterococcus faecalis from the root canal was ProTaper Next system in comparison to OneShape Apical and Hand K-File.

Development of endodontic sealers containing antimicrobial-loaded polymer particles with long-term antibacterial effects

ObjectiveThe objective of this study is to prepare new dental resins with a long-lasting antimicrobial activity. Specifically, this study evaluates an approach for controlling infection in root canals using sealers containing polyhydroxyethyl methacrylate trimethylolpropane trimethacrylate (polyHEMA/TMPT) particles loaded with cetylpyridinium chloride (CPC). In addition, the physical properties of sealers containing CPC-loaded polyHEMA/TMPT particles (CLP) are determined. MethodsPolyHEMA/TMPT particles with 10 (10%-CLP) and 25wt.% CPC (25%-CLP) with different particle sizes were fabricated and incorporated in HEMA-based sealers. CPC-release profiles were evaluated over 14 days of immersion in water, followed by 14 days of storage and 14 days of water immersion. The antibacterial activity of these sealers against Enterococcus faecalis in dentinal tubules was assessed using a root-canal-infection model. Their sealing abilities were evaluated by fluid filtration and physical properties were tested according to the ISO 6876 standard. The long-term antibacterial activity of the cured sealer containing 25%-CLP (∼21μm particle diameter) was re-assessed after 1 year of storage. ResultsAfter 28 days of immersion, 25%-CLP exhibited a higher and sustained CPC release unlike 10%-CLP. Residual bacteria in root dentinal tubules were eradicated by obturation with 25%-CLP-containing sealers. The incorporation of 25%-CLP (∼21μm) had no adverse effects on the sealing ability and physical properties of the sealer and resulted in long-term antibacterial activity. SignificanceThe incorporation of CPC-loaded particles in HEMA resins yielded endodontic sealers with long-term bactericidal activity against E. faecalis in root canals. These sealers can potentially be used to prevent recurrent apical periodontitis.

Photodynamic therapy associated final irrigation in root canals of the primary teeth.

The aim of this study was to analyze, in vitro, the reduction of Enterococcus faecalis in root canals of primary teeth after final irrigation and photodynamic therapy (PDT) use. Twenty primary molars were contaminated with Enterococcus faecalis. The teeth were randomly distributed into four groups according to the irrigation solutions and PDT use: G1 (Saline solution and no PDT use), G2 (17 % EDTA and no PDT use), G3 (Saline solution and PDT use) and G4 (17 % EDTA and PDT use). For PDT, 0.005 % toluidine blue was chosen as the photosensitizer, which was inserted in the canals with sterile paper cones. Bacterial counts were performed with a BHI test in blood agar plate, where bacteria were collected inside the canal for 30 s using sterile paper cones. The collection took place before and after the irrigation and PDT protocols. The samples were diluted, spread onto a blood agar plate and then incubated at 37 °C for 24 h. There was a reduction of the microbiota from the irrigation solutions before and after the final irrigation for all groups. It was observed a statistically significant reduction (p < 0,05) when PDT was used (97.6 % at the saline solution and 89.8 % at the 17 % EDTA) when compared to the groups with no PDT use. Our data demonstrated that PDT, according to the parameters used, increased the disinfection performance of the solutions tested in the root canals of primary teeth.

Comparative evaluation of photoactivated disinfection and sonic irrigation as an adjunct to conventional irrigation on Enterococcus faecalis in root canals: An in vitro study

Objective: The aim of the in vitro study was to compare the antibacterial efficacy of photoactivated disinfection (PAD), sonic irrigation as an adjunct to conventional irrigation against Enterococcus faecalis in vitro.Materials and Methods: A total of 75 extracted teeth were selected and prepared followed by inoculation with strains of E. faecalis, and a preirrigation sample was collected using sterile paper points. These teeth were then divided randomly into three groups for irrigation: Group I (Conventional irrigation), Group II (PAD), and Group III (EndoActivator) followed by postirrigation sample collection using the sterile paper points. The samples were swabbed on blood agar plates and incubated followed by the calculation of colony-forming units (CFU's).Results: The results were statistically analyzed using the SPSS software version 18.0. On comparing the mean values among the groups, the reduction in the number of CFU's after the treatment protocol was highly significant for all groups (P < 0.001). With the preirrigation sample, there is a statistically significant difference in the values of Group I and Group II (P = 0.047). However, in case of postirrigation samples, there is nonsignificant difference between Group II and Group III.Conclusion: PAD using 940 nm diode laser and methylene blue and endoactivator were more effective than sodium hypochlorite (NaOCl) in reducing E. faecalis counts.

Comparison of effectiveness of Reciproc, Wave One, Protaper, and One Shape rotary instruments in reduction of bacterial load in root canals

Aim: To compare the effectiveness of Reciproc, Wave One, Protaper, and One Shape rotary instruments in reduction of E. faecalis in root canals. Methodology: In this in-vitro study, after initial stages of canal enlargement and irrigation, a suspension containing Entrococcus faecalis was inoculated into the root canals of 84 extracted single-canal premolars. The samples (apart from 2 positive and 2 negative controls) were randomly assigned into 4 groups according to rotary instruments used: Reciproc, Wave One, One Shape, Protaper. Each group was then subdivided to 2 groups based on irrigating solutions of normal saline and NaOCl. After instrumentation, the root canals were filled with brain-heart infusion (BHI) broth. Finally bacterial colony forming units (CFU) were counted. Results: Reduction in number of bacterial colonies before and after instrumentation and irrigation was not significantly different in different rotary instrument systems (P=0.128, F=1.955). However, NaOCl was more effective in reduction of bacterial load compared to normal saline (P<0.001, F=15.528). Conclusions: All rotary instruments used in the study are effective in reduction of the bacterial load.

Correction to: Antibacterial efficacy of 810nm diode laser on the biofilm formation by Enteroccocus faecalis in root canals: an in-vitro study

Correction to: Antibacterial efficacy of 810nm diode laser on the biofilm formation by Enteroccocus faecalis in root canals: an in-vitro study

Antibacterial efficacy of 810-nm diode laser on the biofilm formation by Enterococcus faecalis in root canals: an in vitro study

This study aimed to evaluate the antibacterial efficacy of 810-nm diode laser on the root canals infected with Enterococcus faecalis biofilm-like structure by using comparable and safe parameters. The root canals of 52 extracted human single-rooted teeth were prepared, 4 teeth allocated as negative control and 48 teeth inoculated with E. faecalis for 3 weeks. The teeth were then randomly divided into the following 4 experimental groups: Group NaOCl (n = 12), 17% EDTA + 5.25% NaOCl + saline; Group DL1 (n = 12), 17% EDTA + 1 W diode laser + saline; Group DL2 (n = 12), 17% EDTA + 1.5 W diode laser + saline; Group S (n = 12), Saline. Samples were obtained from dentin chips before and after the interventions. A reduction in colony count was assessed by counting the colony-forming units. Compared to the control group, significant reductions were noted in E. faecalis colony counts in all groups (p .05). The greatest reduction in colony count (98.9%) was noted in the Group NaOCl. The difference in this respect between the Group DL2 and Group S (p .05). Our results demonstrated two different parameters of 810-nm diode laser showing the significant antibacterial effect on E. faecalis biofilm but it was not as effective as NaOCl irrigation.

The effect of a chemomechanical protocol to eliminate microorganisms from pulpectomized primary teeth: three case reports.

Introduction: Description of the bacterial community before and after chemomechanical preparation (CP) with the removal of a smear layer (SL) in pulpectomized primary teeth has been little reported. Objective: These case reports describe the presence of total microorganisms and Enterococcus faecalis in root canals of primary incisors before and after CP with SL removal. Case Reports: Microbiological samples were collected from the root canals of three children (3.66±0.58 years old) with necrosis (n=2) and irreversible pulpal inflammation (n=1) in maxillary primary incisors. After teeth isolation with a rubber dam and antisepsis of the operative field, the sample collections were performed with sterile absorbent paper cones before and after the CP, which included irrigation with 2.5% sodium hypochlorite followed by 6% citric acid to remove the SL. The collected samples were analysed immediately at the end of the clinical procedures. The plates were incubated anaerobically for 48 hours at 37°C. The results were expressed as colony forming units (CFU)/mL. Results: Two of the three teeth showed total microorganisms before the CP. One incisor had no microorganisms in the initial collection. No CFU was counted in the samples collected after CP. Moreover, E. faecalis was not observed any time, either before or after the CP. Conclusions: E. faecalis was not detected in any sample, yet two of the three root canals had microorganisms before CP. In cases where microorganisms were initially found, 100% elimination was observed after the applied protocol.

Evaluation the Antimicrobial Efficacy of NaOCL-EDTA, MTAD and NaOCL-citric Acid Against Enterococcus faecalis in Root Canals of Primary Teeth (an in vitro study)

Evaluation the Antimicrobial Efficacy of NaOCL-EDTA, MTAD and NaOCL-citric Acid Against <i>Enterococcus faecalis</i> in Root Canals of Primary Teeth (an <i>in vitro</i> study)

An in vitro determination of antibacterial effect of silver nanoparticles gel as an intracanal medicament in combination with other medicaments against Enterococcus fecalis.

Aim:The main aim of the study is to compare the antibacterial effect of Silver nanoparticle gel alone and combination of silver nanoparticle gel with various medicaments.Materials and Methods:Intracanal dressings: Group 1 –Silver Nanocure gel, Group 2 - Silver Nanocure gel+ Cavisept gel(1:1),Group 3- Silver Nanocure gel+ Aveu-Cal gel(1:1) ,Group 4 – Silver Nanocure gel +Cavisept gel +Aveu-Cal gel(1:1:1) were taken on a culture plate inoculated with E.faecalis. Antibacterial activity was assessed using Agar diffusion test and results were noted as diameter of growth inhibition zone.Statistical Analysis:Student t –test was used to analyse results.Results:The diameter of combination of Silver nanocure gel+Cavisept +Aveu-Cal gel(1:1:1) was highest in comparison to other medicaments tested.Conclusion:Intracanal dressing with a combination of all the three {Silver nanocure gel+Cavisept +Aveu-Cal gel(1:1:1) } is the best treatment for elimination of highly resistant Enterococcus faecalis in root canals.

Bactericidal efficacy of three parameters of Nd:YAP laser irradiation against Enterococcus faecalis compared with NaOCl irrigation.

The success of endodontic treatment depends on the thorough removal of microorganisms from the root canal system. The search for new ways to eliminate the microorganisms is therefore justified. Nd:YAP is a laser that uses yttrium aluminum perovskite, doped with neodymium crystal, as active laser medium. We used the Nd:YAP laser in an in vitro experiment to evaluate the bactericidal effect of three parameters of Nd:YAP laser-activated irrigation on biofilms of Enterococcus faecalis in root canals. The canals of 45 extracted human single-root teeth were prepared on a #35 Mtwo instrument and contaminated with E. faecalis for 14days. Forty infected single-root teeth were then randomly divided into four groups according to the irrigation agitation protocols as follows: 5.25% sodium hypochlorite (NaOCl), Nd:YAP laser (180mJ) + NaOCl, Nd:YAP laser (280mJ) + NaOCl, and Nd:YAP laser (360mJ) + NaOCl. The remaining bacteria were counted immediately using the cell count method. Teeth were firstly spilt and one half examined by scanning electron microscopy (SEM). The other half involved examination of bacterial colonization in dentinal tubules using confocal laser scanning microscopy (CLSM). Nd:YAP laser (280mJ) + NaOCl and Nd:YAP laser (360mJ) + NaOCl completely removed the E. faecalis biofilms from the root canal walls and made it the cleanest among the treatment groups. Bacterial reductions in the treatment groups for dentinal tubules are presented in a descending order as follows: Nd:YAP laser (360mJ) (53.7%), Nd:YAP laser (280mJ) (51.5%) > Nd:YAP laser (180mJ) (45.3%) > 5.25% NaOCl (31.9%) > control (19.3%) (p < 0.05). Nd:YAP laser of 280mJ and 360mJ showed effective bactericidal effect in removing E. faecalis biofilm from the root canal walls and dentinal tubules.

Evaluation of the mono instrument (Wave One) mechanical action on the bacterial load reduction: In vitro study of 32 permanent human teeth.

Context:Enterococcus faecalis is the most common bacteria found in infected root canals.Aim:The purpose of this study was to evaluate the effect of the mono instrument (wave-one®) on the reduction of E. faecalis in root canals.Materials and Methods:Thirty-two human monoroot teeth were used. After sterilization by autoclave, the teeth were infected by E. faecalis and incubated for 24 h. Each tooth underwent sampling before and after the root canal shaping. After serial dilution, samples were incubated, and colony-forming units were counted.Results:The mono instrument technique reduced infection by E. faecalis in root canals of 30 teeth. The mean bacterial load (log10) was 3.98 before treatment and 1.20 after treatment. The paired t-test showed a significant mean difference (log10) of the bacterial load before and after treatment (P < 0.0001).Conclusion:This study found that the mono instrument (Wave One®) significantly decreases bacterial load in root canals. However, the instrument alone is not enough to eradicate infections; thus, the use of a complementary antimicrobial is required.

Bactericidal effects and smear layer removal of Er:YAG-laser radiation against Enterococcus faecalis in root canals

To evaluate the cleaning ability of Er:YAG laser against Enterococcus faecalis in root canals. Methods: The single-rooted human teeth were sterilized and inoculated with Enterococcus faecalis and were randomly assigned into 2 groups. A group of teeth was irrigated with saline during root canal preparation while another group with NaClO. After mechanical preparation, the two groups were randomly divided into 3 subgroups according to the different treatments: Samples, laser radiation, and calcium hydroxide intracanal medication for 7 days. Bactericical effects were compared among groups. Root canal walls and dental tubules were observed under scanning electron microscope. Results: Er:YAG laser was the most efficient way for anti-bacteria among the groups (P<0.05), but there was no significant difference between the 2 laser groups (P>0.05). Meanwhile the smear laser was efficiently removed by laser compared with other treatments, and the laser could open the dentinal tubules. Conclusion: Er:YAG laser can be effectively used for root canal disinfection without NaClO and Ca(OH)2.

Determination of minimum instrumentation size for penetration of diode laser against Enterococcus faecalis in root canals using scanning electron microscope: An in vitro study

Aim: The aim of this study was to determine minimum instrumentation size for penetration of diode laser against Enterococcus faecalis in root canals using scanning electron microscope (SEM). Methodology: Fifty-five single-rooted human permanent maxillary anterior teeth were selected. The sterilized specimens were inoculated with 5 μl E. faecalis culture grown in diluted brain–heart infusion broth and incubated at 37°C for 4 weeks. After 4 weeks, 5 samples were selected as baseline group to evaluate the depth of penetration of E. faecalis . Remaining 50 samples were divided into 5 groups based on the apical enlargement size using ProTaper file system: Group 1 – canal preparation done till #F1 size file; Group 2 – canal preparation done till #F2 size file; Group 3– canal preparation done till #F3 size file; Group 4 – canal preparation done till #F4 size file; Group 5 – canal preparation done till #F5 size file. The canals were prepared and then irradiated with 940 nm diode laser at a power setting of 1.5W for 5 s. The procedure was repeated 4 times with intervals of 10 s between each one. All the samples were then transversely sectioned at 2 mm and 5 mm from the apex. Each section was then examined under a SEM to evaluate the depth of penetration of E. faecalis in the baseline group and depth of penetration of diode laser in the experimental groups. The results were analyzed using the two-way ANOVA and Tukey's multiple post hoc test. Results: Depth of penetration of laser was highest in Group 3 in apical third region and was statistically significant when compared to Group 1 and Group 2 in the middle and apical third regions. However, no statistically significant difference was noted between Group 3, Group 4, and Group 5. Conclusion: It can be concluded that the apical instrumentation to a size F3 using ProTaper file system along with irradiation using a diode laser showed a greater depth of penetration into dentin and thus reducing residual microorganisms. Furthermore, conserving as much tooth structure as possible, thereby increasing the predictability of success.