Microbiota Association and Profiling of Gingival Sulci and Root Canals of Teeth with Primary or Secondary/Persistent Endodontic Infections.

INTRODUCTION: Microbiota associated with primary endodontic infection (PEI) and secondary/persistent endodontic infection (SPEI) must be characterized to elucidate pathogenesis in apical periodontitis and bacterial biomarkers identified for diagnostic and therapeutic applications. METHODS: This study analyzed the microbial community profiles of root canals and gingival sulci (sulcus-E) for teeth with PEI (n = 10) or SPEI (n = 10), using the Illumina MiSeq platform. Bacterial samples from gingival sulci (sulcus-C) of healthy contralateral teeth served as controls. RESULTS: There were 15 phyla, 177 genera, and 340 species identified. The number and diversity of bacteria in root canals did not differ significantly between PEI and SPEI. Proteobacteria, Firmicutes, Fusobacteria, Bacteroidetes, and Actinobacteria were the dominant phyla in both groups. At the genus level, Lancefieldella, Bifidobacterium, Stomatobaculum, and Schaalia were enriched in root canals with SPEI. Of significance, Lancefieldella was observed in both root canals and sulcus-E of teeth with SPEI. At the species level, Neisseria macacae, Streptococcus gordonii, Bifidobacterium dentium, Stomatobaculum longum, and Schaalia odontolytica were increased significantly in root canals with SPEI compared to PEI. Oribacterium species, Streptococcus salivarius, Lancefieldella parvula, Prevotella denticola, and Oribacterium asaccharolyticum were more abundant in sulcus-E of teeth with SPEI compared to PEI. CONCLUSIONS: There were distinctive and differing predominant bacterial species associated with the root canals and gingival sulci between teeth with PEI and SPEI. Specific bacteria identified in sulcus-E and root canals of teeth with SPEI could serve as noninvasive diagnostic biomarkers for detecting SPEI.

An In Vitro Evaluation of the Antimicrobial Efficacy of a Novel Irrigant Using Next-Generation Sequencing.

INTRODUCTION: To evaluate the antimicrobial activity of Triton irrigation versus 4% sodium hypochlorite (NaOCl) utilizing a direct contact test and an extracted tooth model. METHODS: In the first experiment, a direct contact test was conducted to compare bacterial DNA removal and microbial diversity changes following irrigation with 4% NaOCl or Triton. Hydroxyapatite and dentin discs were inoculated with subgingival human-derived dental plaque for 2 weeks utilizing the Center for Disease Control biofilm reactor and subsequently challenged with the root canal irrigants for 5 minutes. In the second experiment, teeth contaminated with a multispecies biofilm (n = 24) were assigned into two treatment groups, NaOCl or Triton irrigation. Samples were obtained for quantitative real-time polymerase chain reaction and next-generation sequencing analysis before and after instrumentation. The Shannon and Chao1 indices were used to measure alpha diversity. The Bray-Curtis dissimilarity and ANOSIM was used to measure beta diversity. Differences in abundances of genera were evaluated using Kruskal-Wallis test with Bonferroni corrections. RESULTS: The direct contact test revealed no significant differences in the bacterial load based on 16S rRNA gene molecules/µL, reads, or differences in the Shannon index among groups. In the extracted tooth model, a bacterial load reduction of log10 3.08 ± 0.69 and 2.76 ± 0.91 were found for NaOCl and Triton, respectively (P = .348). Next-generation sequencing showed fewer reads, lower Chao1, and beta diversity values when pretreatment and post-treatment samples were assessed in both experimental groups (P < .0001). The Kruskal-Wallis analysis found that 17 genera of bacteria were over-represented in minimal values in the Triton post-treatment group, 14 of these genera represented less than 1% of the microbial community. CONCLUSIONS: Both irrigants had limited antimicrobial activity in the direct contact test. When used in conjunction with mechanical instrumentation both irrigants were able to reduce the bacterial DNA load and diversity in comparison with pretreatment communities. The NaOCl irrigation, followed by ethylenediaminetetraacetic acid flush, was more effective in decreasing DNA counts from low-abundance organisms.

Endodontic Microsurgery Outcomes over 10 Years and Associated Prognostic Factors: A Retrospective Cohort Study.

INTRODUCTION: This retrospective cohort study aimed to evaluate long-term healing outcomes (10-17.5 years) after contemporary endodontic microsurgery (EMS) and identify the associated prognostic factors. METHODS: Clinical and radiographic data of an EMS cohort (2006-2013) from the electronic database of the dental hospital were reviewed retrospectively by 2 independent examiners to determine their survival and healing outcomes, and potential prognostic factors were analyzed by Cox proportional hazards regression and logistic regression (α = 0.05). RESULTS: Through strict inclusion and exclusion criteria and 721 EMS-treated teeth in the cohort, 309 (42.9%) were included (male = 35.0%; female = 65.0%; age = 45.83 ± 15.53 years) with a mean final follow-up of 152.26 ± 26.37 months (range, 120-211 months; median = 148 months). Clinical and radiographic assessments found an 80.5% 10-year survival rate with 63.4% of success. Collectively, tooth type, tooth mobility, preoperative lesion size, clinical crown-to-root ratio, and crown restorations at follow-up were significantly associated with long-term success and survival over 10 years. CONCLUSIONS: The preoperative status and condition of the tooth including its alveolar bone support and adequate full-crown restorations may be relevant prognostic determinants of success and survival after EMS over time.

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

AIM: To 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. METHODOLOGY: Twenty-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. RESULTS: Quantitative 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). CONCLUSION: Quantitative 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.

Present status and future directions of intracanal medicaments.

Two fundamental goals of endodontic treatment are to prevent or treat apical periodontitis. From a predictive perspective, several variables can affect the outcome of root canal treatment. Some of these variables depend on intraoperative factors, which include irrigation technique, size of the apical preparation, use of intracanal medicaments or the number of appointments necessary to complete the treatment. However, the outcome may also be affected by host and microbial factors. The intensity of periradicular bone loss or tissue damage, the presence of preoperative pain and associated conditions such as mechanical allodynia and central sensitization, the anatomical complexity of the apical portion of the canal, and the virulence and longevity of the bacterial infection can all have a profound influence on the outcome. Furthermore, numerous medical conditions have been reported to decrease the capability of the immune system to heal the periapical tissues. It is the clinician's responsibility to analyse these variables and incorporate them into the disinfection strategy to maximize the chances of healing. This narrative review will focus on the present status of intracanal medicaments, the clinical indications for their use and future directions for research.

A novel approach in assessment of coronal leakage of intraorifice barriers: a saliva leakage and micro-computed tomographic evaluation.

The efficacy of amalgam, Fuji-Plus, Geristore, and mineral trioxide aggregate (MTA) as intraorifice barriers was compared in a simulated saliva leakage model. Fifty teeth were divided into 4 experimental (n = 10 each) and 2 control groups (n = 5 each). Two millimeters of the materials was placed as intraorifice barriers and brought into contact with human saliva in a coronal reservoir. Bacterial leakage into the apical reservoir was assessed daily for 3 months. Geristore barriers leaked significantly more often (5/10) than Fuji-Plus (0/10, P < .05) at 60 days. The first Fuji-Plus sample leaked after 70 days; after 90 days, 3 (Fuji-Plus), 4 (MTA, amalgam), and 6 (Geristore) samples leaked. There were no significant differences between the experimental groups at that time point. Three-dimensional gap volumes in the barrier-dentin interface and the porosity of the barrier materials were compared by using micro-computed tomography (microCT). A measurable gap was evident in only 1 specimen with an MTA barrier. MTA was significantly less porous than Fuji-Plus and Geristore (P < or = .05), whereas amalgam was too radiopaque to allow microCT measurements. In conclusion, Fuji-Plus might be an effective intraorifice barrier (up to 70 days in vitro), but all 4 materials showed leakage in some specimens at 90 days.