Root Canal Samples Research Articles

Immediate clinical and microbiological evaluation of the effectiveness of 0.5% versus 3% sodium hypochlorite in root canal treatment: A quasi-randomized controlled trial.

To test the hypothesis that in the daily routine of a specialist clinic in endodontics that irrigation during root canal preparation with 3.0% NaOCl will result in fewer postoperative samples with cultivable bacteria than irrigation with 0.5% buffered NaOCl but, at the same time, will not result in a higher frequency of postoperative pain nor swelling. Two hundred ninety-eight patients were enrolled in the study and were randomly assigned into two groups - 0.5% NaOCl and 3% NaOCl. All endodontic diagnoses were included. Root canal treatment was performed, and bacterial sampling was carried out prior to root filling. The patients were requested to complete a form regarding pain and swelling seven days postoperatively. Fisher's exact test, Mann-Whitney U-test, Mantel-Haenszel chi-squared and the chi-squared test with a significance level of P<0.05 were used for statistical analysis. Multivariable logistic regression was used to adjust for confounders. In the 0.5% NaOCl group, 18 (13.4%) of the root canal samples were positive; in the 3% NaOCl group, the corresponding number was 24 (18.6%). The mean difference of -5.2% (95% CI: -14.8 to 4.4) was not significant (P=0.33). In the 0.5% NaOCl group, 57 (53.8%) patients reported some pain; in the 3% group, the corresponding number was 56 (53.3%). The mean difference of 0.4 (95% CI: -14.0 to 14.8) was not significant (P=1.0). In the 0.5% NaOCl group, 5 (5.1%) patients reported swelling; in the 3% NaOCl group, the corresponding number was 18 (17.8%). The mean difference was 12.7 (95% CI: 3.1-22.4), which was significant (P=0.0084). The difference in the concentration of NaOCl (0.5% vs 3%) had no significant impact on the number of positive cultures and did not influence either the frequency or the magnitude of postoperative pain. A significantly higher incidence of postoperative swelling was recorded for patients who received a greater concentration of NaOCl(3%).

Clinical Quantitative Antibacterial Potency of Garlic-Lemon Against Sodium Hypochlorite in Infected Root Canals: A Double-blinded, Randomized, Controlled Clinical Trial.

ABSTRACTIntroduction:Sodium hypochlorite for endodontic treatment has been shown to exhibit significant antimicrobial properties, with adverse effects such as sodium hypochlorite accidents. Natural irrigants have shown significant antimicrobial action and the added advantage of being biocompatible. This study proposes an alternative intracanal irrigant made from Garlic-Lemon (Ga-Li) extract.Aim:To evaluate the antimicrobial action of 1.8% Garlic-Lemon (Ga-Li) mixture in contrast to 3% sodium hypochlorite in a tooth diagnosed with asymptomatic apical periodontitis.Materials and Methods:Thirty patients were randomly allocated into two groups: Group A, 3% sodium hypochlorite and Group B, 1.8% Garlic-Lemon. Single- or multirooted teeth root canals were instrumented and prepared by using ProTaper Gold. Root canal samples were taken both pre- and postinstrumentation. These samples were subjected to DNA extraction, amplification, and quantification by using a real-time polymerase chain reaction (qPCR).Results:Samples before preparation (S1) were tested positive for microbial presence, with mean numbers of 7.0 ×107 and 12.4 ×107 bacterial cells for the sodium hypochlorite and Garlic-Lemon groups, respectively. Postpreparation (S2), in sodium hypochlorite and Garlic-Lemon groups, bacterial counts were still present with mean counts seen at 27.4 ×105 and 7.7 ×105 bacterial cells, respectively. Intergroup comparison resulted in a statistically insignificant difference (P > 0.05).Conclusion:Garlic-Lemon has shown microbial load reduction that is as effective as sodium hypochlorite, with the highest mean bacterial reduction percentage. The results of the present randomized, controlled clinical trial suggest that Garlic-Lemon is a potential new alternative as an endodontic irrigant.

Metagenomic investigation of bacteria associated with dental lesions: a cross-sectional study

Background Dental caries is considered as one of the most significant global health problem over the world. Dental caries initiates from bacterial shifts within the supragingival biofilm, then a polymicrobial biofilm is formed on the surface of tooth, and finally various bacterial species aggregate in a complex-organized manner. The exploiting variability in 16S rRNA gene sequence has been considered as a cost-efficient high-throughput characterization approach in human oral microbiome investigations. The aim of this study is to characterize bacterial species associated with superficial dental biofilm, underlying carious dentine and root caries lesion by16S rRNA gene-based metagenomic analysis. Material and Methods Herein, the bacterial communities in carious dentin lesion, biofilm and root canal samples of 30 subjects (aged 4–76 years) admitted to a clinic in Tehran during 2017 were investigated using a culture independent approach. Total genomic DNA of each tissue was subjected to metagenomic identification of bacteria using a nested PCR assay and 16S rRNA library construction method. Results 31 samples collected from 30 consenting patients (29 samples from 29 patients ant two biofilm samples from one patient). Bioinformatics analyses of a-800bp sequences of the second step of Nested-PCR revealed presence of 156 bacterial isolates in carious (n=45), biofilm (n=81) and root canal (n=30) specimens. Prevotella spp., Lactobacillus vaginalis, and streptococcus spp. showed higher prevalence in carious dentin, root and biofilm samples, respectively. Conclusions Exploring the dental microbiota and comparing them in health or diseased conditions is critical step in the determination of human general health. The method applied in this study could identify bacteria related to the three dental lesions. However, due to lack of data for comparison in Genbank or because of the sequence similarity lower than 98% for most identified bacteria, the use of more powerful approaches like NGS platforms or typing of multiple loci (MLST) in future studies is recommended. Key words:Bacterial composition, dental caries, dental biofilm, oral microbiome.

Distribution of Rothia species in root canals in a Japanese population

Rothia species are components of the normal oral microflora, which have been recognized as emerging opportunistic pathogens in immune compromised hosts. This study was performed to investigate the distribution of Rothia species in infected root canals. The correlations of clinical findings with the presence of Rothia species were also evaluated. A total of 200 root canal samples, including 92 primary infections and 108 secondary infections, were collected from 200 Japanese patients. Polymerase chain reaction (PCR) targeting the 16S rRNA gene was performed to detect three Rothia species, i.e., Rothia mucilaginosa, Rothia aeria, and Rothia dentocariosa. The detection frequencies of R. mucilaginosa, R. aeria, and R. dentocariosa were 49/200 (24.5%), 95/200 (47.5%), and 55/200 (27.5%), respectively. There were no significant differences in the detection frequencies between primary and secondary endodontic infections. The detection frequency of R. mucilaginosa in cases with gingival swelling was 42.9%, and there were significantly more cases positive than negative for this species (P = 0.042). The presence of R. aeria also showed correlations with radiolucency around the root apex (P = 0.001) and pain on percussion (P = 0.044). Quantitative real-time PCR revealed that the relative abundance of R. mucilaginosa in total bacterial counts ranged from 0.04% to 91.8%. These results indicated that Rothia species colonize root canals at relatively high frequency, and that root canals are potential reservoirs of these pathogens. The results also suggest that Rothia species are involved in the pathogenesis of apical periodontitis.

Prevalence of Candida albicans in primary endodontic infections associated with a higher frequency of apical periodontitis in type two diabetes mellitus patients

To identify the prevalence of C. albicans in primary endodontic infections of type two diabetes mellitus (T2DM) patients and compare their clinical and radiographical characteristics with a non-diabetic control group, establishing the possible relationship between primary endodontic infection, T2DM, and C. albicans, since diabetes mellitus (DM), influences the development, course, and response to the treatment of apical periodontitis, but the presence of Candida albicans (C. albicans) has not been considered before. A total of 120 patients were selected and divided into two groups: 60 T2DM diagnosed patients and 60 non-diabetic controls. A clinical examination and radiographic analysis were performed to establish a periapical index score (PAI). Root canal samples were taken. Deoxyribonucleic acid (DNA) was extracted, and specific primers were used to identify C. albicans by polymerase chain reaction (PCR). A twofold increase in the prevalence of C. albicans in T2DM patients was observed in contrast to control patients (p = 0.0251). Sixty-five percent of T2DM patients with positive C. albicans scored a ≥ 3 PAI, while only 27% of the patients without C. albicans had a ≥ 3 PAI score (p = 0.0065). Long-term DM patients presented C. albicans more frequently (p < 0.0001). In this study, long-term T2DM patients carried C. albicans in their root canals more frequently when having a primary endodontic infection. Furthermore, this C. albicans presence seems to be related to a higher frequency of apical periodontitis.

Microbiota of periodontal pockets and root canals in induced experimental periodontal disease in dogs.

To investigate the relationship between the microbiota of periodontal pockets (PP) and root canals (RC) in dogs submitted to experimental periodontal disease (ExPD). ExPD was induced by combining cotton and wire ligatures. After 125days, microbiological samples were collected from PP and RC. Strains isolated from 19 teeth were submitted to DNA extraction, 16S rRNA gene amplification and gene sequencing. Pearson's χ2 - and Fisher's exact tests and McNemar's test were used when appropriate. The number of species in PP was greater than in RC, with prevalence of obligate anaerobes and Gram-negative bacteria. In the PP predominated Fusobacterium necrophorum, Porphyromonas gingivalis, Prevotella loescheii, Campylobacter gracilis and Veillonella parvula. In the RC samples, 9 had microbial growth, with predominance of the following genera: Staphylococcus, Streptococcus and Neisseria. Eight genera were common to both sites in the same tooth. PP presented a greater number of species than the RC. No significant difference was observed in the species found in PP and RC in the same tooth. Microbial composition of the RC could be modulated by the presence of periodontal disease, especially in cases of severe periodontal destruction. RC microbiota was less complex and diverse than the PP.

Correlation Between Volume of Root Canal, Cultivable Bacteria, Bacterial Complexes and Endotoxins in Primary Infection.

This clinical study was conducted to correlate the levels of endotoxins and culturable bacteria found in primary endodontic infection (PEI) with the volume of root canal determined by using Cone Beam Computed Tomography (CBCT); and to evaluate the bacterial diversity correlating with clinical features. Twenty patients with PEI were selected and clinical features were recorded. The volume (mm3) of root canal was determined by CBCT analysis. Root canal samples were analyzed by using kinetic LAL-assay test to determine the levels of endotoxins and anaerobic technique to determine the bacterial count (CFU/mL). DNA was extracted from all samples to determine bacterial diversity and quantified by using Checkerboard-DNA-DNA- Hybridization. Culturable bacteria and endotoxins were detected in 100% of the root canal samples. Linear regression analysis revealed a correlation between root canal volume and presence of anaerobic bacteria (p<0.05). Positive correlations were found between bacteria species and presence of different clinical features (p<0.05). After grouping the bacteria species into bacterial complexes, positive associations were found between green, orange and red complexes with presence of sinus tract (p<0.05). This clinical study revealed that larger root canals hold higher levels of culturable bacteria in PEI. Thus, the interaction of different virulent bacteria species in complexes seems to play an important role in the development of clinical features.

PCR-based detection of three anaerobic bacteria associated with endodontic-periodontic lesions in type-2 diabetic and nondiabetic subjects.

Aim:The aim of this study is to clinically isolate and detect three anaerobic bacteria associated with endodontic-periodontal lesions in type-2 diabetic and nondiabetic patients using polymerase chain reaction (PCR).Materials and Methods:Sixty patients presenting endodontic-periodontal lesions were divided into two groups. Thirty patients with type-2 diabetics (Group 1) and 30 nondiabetic patients (Group 2) were evaluated for the presence of three anaerobic bacteria. Clinical examinations, periapical radiographs, and microbiological sampling from the canal system and periodontal pockets were performed. Qualitative evaluation of bacteria was performed using a multiplex PCR for Porphyromonas gingivalis and Prevotella intermedia. Statistical analysis was performed using Pearson's Chi-square test and Fischer's exact test.Results:Enterococcus faecalis (73.3%) was the predominant bacteria isolated from the root canal in type 2 diabetic patients, followed by P. gingivalis (70%) and P. intermedia (36%) compared to 53.3%, 43.3%, and 23.3%, respectively, among nondiabetic patients. P. gingivalis (73.3%) was the predominant bacteria isolated from periodontal pockets in type II diabetic patients followed by P. intermedia 50% and E. faecalis 30% compared to 36.6%, 33.3%, and 30%, respectively, among nondiabetics. P. gingivalis was detected in the root canal and periodontal pocket in almost similar numbers (70% and 73%), respectively, among type-2 diabetics.Conclusion:Detection of P. gingivalis, P. intermedia, and E. faecalis in both root canal and periodontal pocket samples confirm a viable pathway for the spread of infection through dual sites. Since in the present study, P. gingivalis was found to be present in similar numbers in dual sites among type 2 diabetic patients, importance should be given in treating such anaerobic bacteria in immune-compromised patients.

Root canal preparation using micro-computed tomography analysis: a literature review.

This literature review has critically analyzed the published research related to the biomechanical preparation of root canals with three-dimensional analysis using micro-computed tomography (micro-CT). In December 2017, six databases (PubMed, Cochrane, Web of Science, Embase, Scopus, and Science Direct) were accessed using keywords to find articles including the use of the micro-CT analysis in biomechanical root canal preparation. There were 60 full articles that were selected, which were screened and read by two authors. The research that was reviewed and analyzed included root canal anatomy and sample selection, changes in canal shape and untouched canal areas, canal transportation and centering ability, and kinematics (motion). Of the studies selected, 49.18% discussed anatomical characteristics, with 54.1% of these studies describing mesial roots of mandibular molars with moderate curvature. Only 35% used a stratified distribution based on root canal system morphology and quantitative data obtained by micro-CT. The analysis of canal transportation and centering ability showed that transport values in the apical third exceeded the critical limit of 0.3 mm in mesial roots of mandibular molars with moderate curvature, especially in the groups in which a reciprocating system was used. In relation to kinematics, 91.70% of the reviewed studies evaluated continuous rotating instruments, followed by reciprocating rotation (38.33%), vibratory (15%), and the adaptive kinematics, which was in only 8.33%. The reciprocating kinematics was associated with higher canal decentralization and transportation indexes, as well as a greater capacity for dentin removal and debris accumulation. This literature review showed that the anatomy, the type of design and kinematics of instruments, and the experimental design are factors that directly influence the quality of biomechanical preparation of root canals analyzed in a qualitative and quantitative manner by micro-CT.

Root Microbiota in Primary and Secondary Apical Periodontitis.

Apical periodontitis is an inflammatory disease of the dental periradicular tissues triggered by bacteria colonizing necrotic root canals. Primary apical periodontitis results from the microbial colonization of necrotic pulp tissues. Secondary apical periodontitis results from a persistent infection of incorrectly treated root canals. The aim of this study was to characterize the microbiota present in primary and secondary intraradicular infections associated with apical periodontitis using 16S rRNA gene amplicon sequencing. Teeth exhibiting apical periodontitis with or without root canal treatment were extracted after informed consent. From each tooth, the intraradicular content as well as a dentin sample (control) were collected and subjected to DNA extraction. PCR amplicons of the V3–V4 region of the bacterial 16S rRNA gene were pooled and sequenced (2 × 300) on an Illumina MiSeq instrument. The bioinformatics analysis pipeline included quality filtering, merging of forward and reverse reads, clustering of reads into operational taxonomic units (OTUs), removal of putative contaminant OTUs and assigning taxonomy. The most prevalent and abundant OTU in both dentin and root canal samples was assigned to anaerobic bacterium Fusobacterium nucleatum. Multivariate analysis showed clustering of microbiota by sample type (dentin vs. intraradicular content) and, in root canals, by pathology (primary vs. secondary infection). The proportions of Enterococcus faecalis and F. nucleatum were, respectively, higher and lower when comparing secondary to primary infected root canals. Co-occurrence network analysis provided evidence of microbial interactions specific to the infection type. The identification of bacterial taxa differentially abundant in primary and secondary intraradicular infections may provide the basis for targeted therapeutic approaches aimed at reducing the incidence of apical periodontitis.

Antimicrobial efficacy of 0.5% peracetic acid and EDTA with passive ultrasonic or manual agitation in an Enterococcus faecalis biofilm model

We compared the antimicrobial efficacy of EDTA and 0.5% peracetic acid (PAA), with manual agitation (MA) or passive ultrasonic irrigation (PUI) in an Enterococcus faecalis biofilm model. Fifty-five single-rooted human premolar teeth were chemo-mechanically prepared and inoculated with E. faecalis for biofilm formation. These were divided into five groups (n = 11): saline solution, PAA+MA, PAA+PUI, EDTA+MA and EDTA+PUI. Root canal sampling and scanning electron microscopy of the canal lumen and dentinal tubule areas at the different root thirds were performed. The images were ranked based on contamination level. Only the PAA groups presented with no bacterial growth, with the remaining groups not presenting significant differences among them. PAA+PUI presented with the highest median position rankings in every third and location, whereas EDTA+MA performed similarly to the saline control. No differences were found when comparing MA and PUI within the same solution, however, PUI was associated with lower contamination levels mean rankings.

Correlation between crestal alveolar bone loss with intracanal bacteria and apical lesion area in necrotic teeth

ObjectiveThis study aimed to analyze the correlation between crestal alveolar bone loss with the presence of some bacterial species in root canals and the apical lesion area of necrotic teeth. DesignData from 20 patients with diagnosis of pulp necrosis and acute apical abscesses, without active periodontal diseases, were evaluated. Patients with history of antibiotic usage three months prior to the study, with exposed pulp cavity, and with probing depth >3 mm were not included. The root size, the distance between the bone crest to the tooth apex in the mesial and distal surfaces, and the apical lesion area were measured from standard periapical radiographies by a calibrated examiner. Root canal samples were collected using sterilized paper points. In multirooted teeth, the largest root canal was sampled. Culture, microbial isolation and identification by phenotypic methods were performed. Spearman correlation and exact Fischer test were calculated between higher/lower existing bone crests, according to the median and the presence of specific bacteria. ResultsNo statistically significant differences were found between occurrence of pathogenic bacteria, such as Porphyromonas gingivalis, Porphyromonas endodontalis, and Prevotella intermedia, and groups with higher/lower degree of bone loss (p > 0.05). A negative significant correlation was found between Parvimonas micra and periodontal bone loss (p = 0.02). Additionally, no statistically significant association was found between crestal bone loss and the apical lesion area. ConclusionsIt was concluded that, in patients without active periodontitis, the presence of pathogenic bacteria in the root canal was not correlated with periodontal bone loss.

Detection of the antimicrobial resistance genes blaTEM-1, cfxA, tetQ, tetM, tetW and ermC in endodontic infections of a Mexican population.

The aim of this study was to identify the prevalence of genes encoding resistance to three groups of antimicrobial agents in root canal samples from primary infection or post-treatment disease in Mexico. A total of 64 subjects requiring root canal treatment because of primary infection or post-treatment disease were enrolled in this cross-sectional analytical study. Root canal samples were obtained and DNA was isolated. Specific primers for six antimicrobial resistance genes (ARGs) and seven bacterial taxa (five genera and two species) were used. Student's t-test, χ2 test and Fisher's exact test were applied where appropriate to detect statistical differences. The blaTEM-1, ermC and tetM genes were found more frequently in the post-treatment disease group compared with the primary infection group. The occurrence of assessed bacteria was similar in both groups, except for Enterococcus spp. and Porphyromonas endodontalis, which were found at a significantly higher frequency in the post-treatment disease group. It was observed that the post-treatment disease group harboured more ARGs. The most frequent ARG was tetW, whereas tetQ and cfxA were not detected in any case. With respect to bacterial taxa, Fusobacterium spp. was present in 100% of samples, whereas Porphyromonas gingivalis was not observed in any of the samples. At least one ARG was detected in all cases; moreover, 32.8% of samples were positive for four ARGs, 54.7% for three ARGs, 9.4% for two ARGs and only 3.1% for one ARG. This indicates a high prevalence and diversity of ARGs in these root canal samples.

Prevotella strains and lactamic resistance gene distribution in different oral environments of children with pulp necrosis.

To determine the presence of Prevotella species, the cfxA/cfxA2, blaZ and blaTEM genes associated with resistance to lactamic agents in different oral niches of children with pulp necrosis. Children with pulp necrosis in primary teeth had samples of saliva, supragingival, pulp chamber and root canal biofilms collected and tested for Prevotella species (P.intermedia, P.nigrescens, P.tannerae) and for beta-lactam resistance genes (cfxA/cfxA2, blaZ and blaTEM). The presence of bacterial DNA was examined through PCR, with a specific primer directed to the 16S rRNA gene. Specific primers were used to detect the Prevotella species and beta-lactam resistance genes. The chi-square test was used to analyse associations between the presence of bacteria and clinical variables. The Cochran's Q test was used to assess whether the proportion of gene detection is the same between different sites. Thirty-two teeth were sampled from 27 patients with a mean age of 5.5years (±1.76). The total detection rate of Prevotella strains was 29.1%, 25%, 21.8% and 32.29% in saliva, supragingival, pulp chamber and root canal samples, respectively. P.nigrescens was the most commonly detected species in all oral niches. The previous use of antibiotics was associated with detection of P.nigrescens in saliva (P=0.03). Pain was associated with the presence of P.nigrescens (P=0.04) and P.tannerae (P= 0.01) in pulp chamber biofilm. blaTEM was detected in the four oral niches, being more frequent (23.8%) in supragingival biofilm (Cochran's Q test, P=0.04). The presence of P.intermedia in SB and PC was associated with the detection of blaTEM in saliva (P=0.04). The cfxA/cfxA2 and blaZ genes were not detected in any of the four oral niches. The oral cavity of children with pulp necrosis had a variable distribution of Prevotella strains in different niches. Saliva, supragingival biofilm, pulp chamber and root canals of primary teeth with necrotic pulps can harbour resistance genes to beta-lactams agents.

Presence of archaea and selected bacteria in infected root canal systems

Infections of the root canal have polymicrobial etiology. The main group of microflora in the infected pulp is bacteria. There is limited data that archaea may be present in infected pulp tissue. The aim of this study was to check the prevalence of archaea in necrotic root canal samples obtained from patients with primary or post-treatment infection. The prevalence of selected bacteria species (Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Synergistes sp.) in necrotic samples was evaluated as well. Sixty-four samples from root canal were collected for DNA and RNA extraction. A PCR assay based on the 16S rRNA gene was used to determine the presence of archaea and selected bacteria. Of the 64 samples, 6 were analyzed by semiquantitative reverse transcription PCR to estimate expression profiles of 16S rRNA, and another 9 were selected for direct sequencing. Archaea were detected in 48.4% samples. Statistical analysis indicated a negative association in coexistence between archaea and Treponema denticola (P < 0.05; Pearson's χ2 test). The main representative of the Archaea domain found in infected pulp tissue was Methanobrevibacter oralis. Archaea 16S rRNA gene expression was significantly lower than Synergistes sp., Porphyromonas gingivalis, and Tannerella forsythia (P < 0.05; Student's t test). Thus, it can be hypothesized that archaea may participate in the endodontic microbial community.

Multiplex polymerase chain reaction detection of selected bacterial species from symptomatic and asymptomatic non-vital teeth with primary endodontic infections.

The aim of the present study was to investigate the presence of selective anaerobic microorganisms in primary root canal infections of symptomatic and asymptomatic non-vital teeth with periapical pathosis using multiplex polymerase chain reaction. A total of 100 root canal samples (50 from symptomatic and 50 from asymptomatic teeth) were obtained from patients with primary endodontic infections. DNA extracted from the samples was amplified by using specific primers for the 16S rRNA gene of each bacterium, and semiquantification was done to analyze the prevalence of microorganisms and their correlation to clinical features. Treponema denticola (T.denticola) was present in 21 (42%) and 29 (58%) samples in the symptomatic and asymptomatic groups, respectively. Tannerella forsythia, Porphyromonas gingivalis (P.gingivalis), and Fusobacterium nucleatum (F.nucleatum) were significantly high (P<.05) in the symptomatic group, whereas Prevotella intermedia was significantly high (P<.05) in the asymptomatic group. The mean counts of T.denticola and F.nucleatum were significantly high (P<.05) in the symptomatic group. For symptoms, P.gingivalis, T.denticola, and F.nucleatum were significantly associated with clinical features. Significant differences exist in the bacterial composition between asymptomatic and symptomatic primary endodontic infections. As well as presence of pathogens, other factors, such as the phenotypic trait of bacteria and interactions among bacterial members, might play a determining role in the pathogenicity of primary endodontic infections.

Bacterial Reduction after Gutta-Percha Removal with Single vs. Multiple Instrument Systems.

Introduction:The aim of this study was to evaluate the effectiveness of a reciprocating single-instrument system (Reciproc-REC) compared with combined continuously rotating multiple-instrument systems [D-Race (DR) and BioRace (BR)] in reducing Enterococcus faecalis (E.f.) after gutta-percha removal. Methods and Materials:Forty-six extracted human maxillary incisors were prepared and contaminated with E.f. strain (ATCC 29212) for 30 days. The samples were obturated and randomly divided into two experimental groups for gutta-percha removal (n=23): a REC group (R50) and a DR/BR group (DR1, DR2 and BR6). A standardized irrigation with 0.9% saline solution was performed. Root canal samples were taken with paper points before (S1) and after (S2) the removal of gutta-percha to establish bacterial quantification by culture. The time required for gutta-percha removal was also recorded. Positive and negative control groups (n=6) were used to test bacterial viability and control asepsis, respectively. Data were analysed using t-Student and one-way ANOVA tests (5% margin of error). Results:The mean percentage of bacterial reduction was significantly higher in DR/BR group (84.2%) than in REC group (72.3%) (P<0.05). The mean time for obturation removal was 74.00 sec in REC group and 107.53 sec in DR/BR group (P<0.05). Conclusion: The combined continuously rotating multiple-instrument system was more effective in reducing bacteria after the removal of gutta-percha than the single-instrument system. None of the tested systems was able to completely eliminate root canal infection after gutta-percha removal. Thus, additional techniques should be considered.

Evaluation of Antimicrobial Efficacy of Triantibiotic Paste, Mixture of Calcium Hydroxide and Omeprazole and Carnosic Acid as Intracanal Medicament against E. faecalis

Introduction: Bacteria plays a principal role in the pathogenesis and progression of pulpal and periapical diseases. The chronic resistant bacterial existence in the root canals has a greater influence on the endodontic treatment outcome by the persistence of periapical tissues. Higher proportions of enterococci, ranging from 29 to 77% are found in filled root canals with the persistent periapical disease. Placement of an intracanal medicament can reduce the bacterial load. Materials and methods: Extracted and decoronated, 72 nos. single-rooted human teeth prepared to maintain the root length of 18 mm were selected for the study. After instrumentation, E. faecalis suspension was inoculated in each of the root canal and teeth were incubated at 37°C for 72 hours within the orbital incubator. Root canal samples were randomly divided into four groups. After placement of various medicaments (namely saline, triantibiotic paste, mixture of calcium hydroxide [Ca(OH)2] and omeprazole and carnosic acid) inside the canal, teeth were divided into three subgroups of five samples and incubated at 37°C under humid conditions for the time period of 24 hours, 48 hours and 7 days within Orbital incubator. Viable cell count assay was used to see the effect of these antimicrobials on E. faecalis biofilm. Results: Results were statistically evaluated using KruskalWallis one-way analysis of variance tests. A p-value <0.05 was considered significant Conclusion: Carnosic acid showed better antimicrobial properties compared to TAP, calcium hydroxide and omeprazole over the experimental period of time.

Odontoblast-like differentiation and mineral formation of pulpsphere derived cells on human root canal dentin in vitro

BackgroundThe revitalization or regeneration of the dental pulp is a preferable goal in current endodontic research. In this study, human dental pulp cell (DPC) spheres were applied to human root canal samples to evaluate their potential adoption for physiological tissue-like regeneration of the dental root canal by odontoblastic differentiation as well as cell-induced mineral formation.MethodsDPC were cultivated into three-dimensional cell spheres and seeded on human root canal specimens. The evaluation of sphere formation, tissue-like behavior and differentiation as well as mineral formation of the cells was carried out with the aid of optical light microscopy, immunohistochemical staining and scanning electron microscopy (SEM).ResultsSpheres and cells migrated out of the spheres showed an intense cell-cell- and cell-dentin-contact with the formation of extra cellular matrix. In addition, the ingrowth of cell processes into dentinal tubules and the interaction of cell processes with the tubule walls were detected by SEM-imaging. Immunohistochemical staining of the odontoblast specific matrix proteins, dentin matrix protein-1, and dentin sialoprotein revealed an odontoblast-like cell differentiation in contact with the dentin surface. This differentiation was confirmed by SEM-imaging of cells with an odontoblast specific phenotype and cell induced mineral formation.ConclusionsThe results of the present study reveal the high potential of pulp cells organized in spheres for dental tissue engineering. The odontoblast-like differentiation and the cell induced mineral formation display the possibility of a complete or partial “dentinal filling” of the root canal and the opportunity to combine this method with other current strategies.

Actinomyces radicidentis and Actinomyces haliotis, coccoid Actinomyces species isolated from the human oral cavity

There are few reports on the bacterial species Actinomyces radicidentis in the literature. In this study, putative A. radicidentis isolates were collected from 16 root canal samples from 601 examined patients. The isolates were examined by biochemical tests, 16S rRNA gene sequencing, Arbitrarily-primed (AP-) PCR, antibiotic susceptibility testing, and MALDI-TOF analyses. In parallel, two A. radicidentis reference strains and two putative A. radicidentis isolates from United Kingdom were tested. Sixteen of the 18 isolates were confirmed as A. radicidentis. The remaining two isolates, both of which were isolated from root canals (one from Sweden and the other from the UK), but were identified as Actinomyces haliotis by sequencing ∼ 1300 base pairs of the 16S rRNA-gene. This isolates had a divergent, but between them similar, AP-PCR pattern, and a common distribution of sequence signatures in the 16S rRNA gene, but were not identified by MALDI-TOF. A. haliotis is a close relative to A. radicidentis, hitherto only been described from a sea-snail. The identity of A. haliotis was confirmed by a phylogenetic tree based on 16S rRNA gene sequences with species specific sequences included, and by additional biochemical tests.The examined bacteria exhibited similar antibiotic susceptibility patterns when tested for 10 separate antibiotic classes with E-tests (bioMérieux). The MIC90 for β-lactams (benzylpenicillin and cefuroxime) and vancomycin was 0.5 mg/L, for colistin and ciprofloxacin 8 mg/mL and for the other antibiotic classes ≤ 25 mg/mL The isolation of A. haliotis from infected dental root canals cast doubt on the accepted opinion that all Actinomyces infections have an endogenous source.