Residual Bacteriome after Chemomechanical Preparation of Root Canals in Primary and Secondary Infections

BackgroundMicroorganisms colonizing the apical root canal system are conceivably the ones directly involved with the causation and maintenance of apical periodontitis.ObjectivesThis article systematically reviews the reports on the microbiome occurring exclusively at the apical root canal of teeth with primary and posttreatment apical periodontitis.MethodsThe electronic databases PubMed, Embase, Web of Science, Science Direct, and Proquest were searched up to August 2023. Clinical studies using culture and molecular microbiology methods to identify the microbial taxa present exclusively in the apical root canal segment of infected teeth with apical periodontitis were included. Studies were critically assessed using the Joanna Briggs Institute Critical Prevalence Assessment Checklist.ResultsFrom 2277 articles initially detected, 52 were selected for full reading and 21 were eventually included in this review. Of these, molecular methods were used in 19 and culture in 2 studies. Ten studies evaluated primary infections, 8 evaluated posttreatment infections, and 3 included both. Cryopulverization of the apical root specimens was conducted in 11 studies. All studies evaluated the prevalence and diversity of bacteria, and only one also reported on fungi. Overall, the most frequent/abundant bacterial taxa found in the apical canal of primary infections were Pseudoramibacter alactolyticus, Olsenella uli, Fusobacterium species, Streptococcus species, Porphyromonas endodontalis, Prevotella species, Actinomyces species, Parvimonas micra, Treponema denticola, Synergistetes species, and an as‐yet uncharacterized taxon. In posttreatment infections, the most prevalent/abundant bacterial taxa included species of Streptococcus, Enterococcus, Fusobacterium, Actinomyces, Pseudoramibacter, Pseudomonas, and Propionibacterium. At the phylum level, Firmicutes was the most represented. The average apical bacterial load ranged from 105 to 106 in primary infections and from 103 to 104 in posttreatment infections.DiscussionMicrobial diversity in the apical part of the root canal system was examined encompassing data from both primary and posttreatment infections. Heterogeneity amongst the studies, especially in sample collection and microbial identification methods, is an important limitation that prevented a meta‐analysis.ConclusionsThere is a pronounced bacterial diversity in the infected apical canal, with a high interindividual variability. Different microbiome compositions at the species/genus level are observed according to the infection type.RegistrationPROSPERO CRD42021275886.

Section: Discussionsupporting

confidence: 91%

Apical root canal microbiome associated with primary and posttreatment apical periodontitis: A systematic review

Siqueira,

Silva,

Romeiro

et al. 2024

“…First, most clinical Illumina MiSeq studies have been focused on characterizing qualitatively the bacterial community profile present in endodontic infections (Gomes et al, 2015;Ordinola-Zapata et al, 2023;Pérez-Carrasco et al, 2023;Rôças et al, 2015). However, to date, few clinical Illumina MiSeq studies have explored CMP's effect on the bacteriome present in PEI (de Castro Kruly et al, 2022;Fouad et al, 2022;İriboz et al, 2018;Zahran et al, 2022). Recently, de Castro Kruly et al ( 2022 İriboz et al, 2018;Zahran et al, 2022), we sequenced the 16S rRNA gene in the V3-V4 region.…”

Section: Discussionmentioning

confidence: 99%

Impact of root canal disinfection on the bacteriome present in primary endodontic infection: A next generation sequencing study

Alquria,

Acharya,

Tordik

et al. 2024

AimTo investigate the bacteriome present in teeth with primary endodontic infection (PEI) and apical periodontitis (AP) and to determine quantitatively and qualitatively the impact of chemomechanical preparation (CMP) using 2.5% sodium hypochlorite NAOCl on the bacteriome found in PEI with AP using the Illumina MiSeq platform.MethodologyThirty‐six paired samples from 18 patients were successfully sequenced and analysed. Samples were collected at two sampling times: before (s1) and after (s2) CMP using 2.5% NaOCl. The DNA was extracted from s1 and s2 samples and quantified using quantitative PCR (qPCR). All 36 samples were sequenced using the Illumina MiSeq platform. Raw V3–V4 amplicon sequencing data were processed with the DADA2 pipeline to generate amplicon sequence variants (ASVs). Alpha diversity metrics representing abundance (Chao1) and diversity and evenness (Shannon, Simpson) were computed. The paired‐sample Wilcoxon's test was used to compare alpha diversity metrics and qPCR counts between s1 and s2. The PERMANOVA method (with 999 permutations) was applied to compare community composition between sample types (s1 versus s2) and between patient IDs. ALDEx2 (ANOVA‐like differential expression tool for high‐throughput sequencing data) to investigate differentially abundant taxa between s1 and s2. A paired‐sample Wilcoxon's test was used to compare alpha diversity metrics and qPCR counts between s1 and s2.ResultsThe qPCR counts were significantly higher in s1 compared to s2 (p = .0007). The Chao1 index indicated no difference in alpha diversity (p < .7019); whereas Shannon (p = .0056) and Simpson (p = .02685) indexes showed higher values in s2. The PERMANOVA test using Adonis2 showed a significant effect of sample time on community composition (R2 = .0630, p = .012). Patient ID also showed a significant effect on community composition (R2 = .6961, p = .001). At the genus level, Dialister, Mogibacterium, Prevotella, and Olsenella were differentially enriched at s1, while Actinomyces, Stenotrophomonas_unclassified, Enterococcus_unclassified, and Actinomyces_unclassified were differentially enriched in s2.ConclusionThe bacteriome present in teeth with PEI with AP is complex and diverse. CMP using 2.5% NaOCl showed a high quantitatively and qualitatively disinfectant impact on the bacteriome present in PEI with AP.

“…The present study investigated the microbial changes after the use of two irrigation protocols in the root canal system of extracted mandibular molars with history of pulp necrosis. To evaluate the microbial reduction, quantification PCR and next‐generation sequencing was performed (Gomes et al., 2015; de Castro Kruly et al., 2022). One advantage of using an ex vivo model is that the microbiome and root canal anatomical variations provided by this model potentially represents the microbial diversity and relative anatomical uncertainty that clinicians face in their daily practice.…”

Section: Discussionmentioning

confidence: 99%

The effect of ultrasonic and multisonic irrigation on root canal microbial communities: An ex vivo study

Park,

Ordinola‐Zapata,

Noblett

et al. 2023

AimTo analyse the effect of ultrasonic irrigant activation (UIA) and the GentleWave (GW) multisonic irrigation (GW) with minimal instrumentation on the root canal microbial diversity in an ex vivo model that used extracted molars with a history of pulp necrosis.MethodologyTwenty‐three mandibular molars were prepared ex vivo for collection of superficial (surface control), pre‐treatment and post‐treatment samples 24 h after extraction. Samples were divided into two groups: UIA using 6% NaOCl (n = 11) and GW group (n = 12). All samples were processed using quantitative real‐time polymerase chain reaction (qPCR) and 16S rRNA next‐generation sequencing to measure microbial diversity before and after the antimicrobial treatment. For qPCR, a t‐test (α = .05) was used to compare the log10 reduction. The Chao1 and Shannon indices evaluated alpha diversity. Differences in community composition (beta diversity) were evaluated by analysis of similarity (ANOSIM). Kruskal–Wallis test with Bonferroni corrections was performed to evaluate the differences in abundances genera in the samples.ResultsQuantitative real‐time polymerase chain reaction revealed an estimated 1.6 and 2.6 log10 reduction for UIA and GW groups respectively (p = .048). An average of 5 ± 4 and 3 ± 5 operational taxonomic units (OTUs) were found in surface's samples in the UIA and GW group respectively. These values were significantly lower (p < .001) compared to the number of preoperative OTUs in those groups (155 ± 79 and 187 ± 121). In assessing beta diversity, there were no significant differences found in pre‐treatment samples (R = .090, p = .070 ANOSIM with Bonferroni corrections). Also, no significant differences in community composition were observed in post‐treatment samples (R = −.05, p = .829). After treatment, there was a significant reduction of Eubacterium using conventional treatment with UIA and a significant reduction of Prevotella using minimal instrumentation with GW irrigation (p = .007 and p = .002 respectively).ConclusionQuantitative PCR analysis revealed a significant reduction in microbial load for GW group. Overall, diversity changes were similar between UIA and GW irrigation in this ex vivo model that used extracted teeth with a history of pulp necrosis. OTUs obtained from the surface sample were negligible and did not affect the statistical outcome of the study.