Comparison of Two Reciprocating and Anatomical Single File Techniques in Cleaning Oval Anatomies.

Introduction: The present study aimed to compare the capability of two single-file shaping systems in disinfecting and cleaning long oval root canals. Materials and Methods: Fifty single-rooted teeth were prepared, contaminated with Enterococcus faecalis and divided into two groups. Two samplings were obtained; S1 before chemo-mechanical preparation and S2 after the preparation. Depending on the group, chemo-mechanical preparation was performed with XP-endo Shaper (XPS) and Wave One Gold (WOG). Five teeth from each group were observed under scanning electron microscopy (1000×) to evaluate the cleanliness of root canals at 3, 6 and 9 mm from the apex. All probability (P-values) were two-tailed, statistical significance was set at 0.05 and analyses were conducted using SPSS statistical software. Results: A significant reduction in the colony forming units was observed from S1 to S2 in both tested groups. In S2, XPS group obtained significantly lower colony forming units (P<0.001). In the cleanliness study, XPS group resulted in significantly cleaner canals compared to WOG. Conclusions: Based on this in vitro study XPS system was more effective in disinfecting and cleaning long oval canals.

Rotary versus reciprocating shaping files in bacterial elimination from long oval canals.

A comparison of the abilities of rotary versus reciprocating files to eliminate viable Enterococcus faecalis populations from the long oval root canals of extracted human teeth. Fifty teeth were contaminated and randomly distributed into two groups (n = 25 each): BT-RaCe group and WaveOne group. Two microbial samples were obtained from each tooth before (S1) and after (S2) instrumentation. The CFUs from the S1 and S2 measurements were calculated and compared between the groups. Both groups showed significantly fewer CFUs in the S2 samples (P < 0.001). In the S2 intragroup comparison, BT-RaCe resulted in significantly fewer CFUs than WaveOne (P = 0.010). In the direct comparison between the rotary multiple file shaping system and the reciprocating single-file system, the multiple file system was more efficient at reducing the microbiological load of viable E. faecalis from long oval root canals.

Comparative analysis of SAF, Protaper Next and BT-Race in eliminating Enterococcus faecalis from long oval canals: An ex vivo study.

Comparison of the ability of newly designed rotary files to eliminate viable Enterococcus faecalis populations from long oval root canals of extracted human teeth to that of the self-adjusting file (SAF). One hundred caries-free, single-rooted, long oval teeth were contaminated with E. faecalis. The teeth were randomly distributed into four groups (n = 25) as follows: G.1, manual; G.2, SAF; G.3, ProTaper Next; and G.4, BT-Race. Two microbial samples were obtained from each tooth with sterile paper points, (s1) before and (s2) after instrumentation. The relative reduction in colony-forming units (CFUs) from s1 to s2 measurements was calculated and compared among the groups using parametric Kruskal-Wallis one-way anova on ranks and Dunn's method (a = 0.05). The results indicated a descending order of the groups with regard to efficacy as follows: BT-Race, Next, SAF and manual. The statistical analysis showed that the relative percentage reduction (RR) of CFUs was lower in the manual group than in the other groups, while the SAF group showed a significantly lower RR than the BT-Race group (P < 0.05). The efficacy in reduction of the microbiological load of viable E. faecalis from long oval root canals was different between the tested endodontic systems.

Interaction of dental pulp stem cells with Biodentine and MTA after exposure to different environments.

OBJECTIVE:: The aim of the present study was to evaluate and compare the cytotoxic effects of Biodentine and MTA on dental pulp stem cells (DPSCs) and to assess cell viability and adherence after material exposure to an acidic environment. MATERIAL AND METHODS:: DPSCs were cultured either alone or in contact with either: Biodentine; MTA set for 1 hour; or MTA set for 24 hours. After 4 and 7 days, cell viability was measured using the MTT assay. Biodentine and MTA were also prepared and packed into standardized bovine dentin disks and divided into three groups according to the storage media (n=6/group): freshly mixed materials without storage medium (Group A); materials stored in saline (Group B); materials stored in citric acid buffered at pH 5.4 (Group C). After 24 hours, DPSCs were introduced in the wells and cell adherence, viability, and cellular morphology were observed via confocal microscopy after three days of culture. Cell viability was analyzed using repeated-measures analysis of variance test with Tukey's post hoc tests (α=0.05). RESULTS:: Biodentine expressed significantly higher cell viability compared with all other groups after 4 days, with no differences after 7 days. Notably, cell viability was significantly greater in 24-hour set MTA compared with 1-hour set MTA and control groups after 7 days. Material exposure to an acidic environment showed an increase in cell adherence and viability in both groups. CONCLUSIONS:: Biodentine induced a significantly accelerated cell proliferation compared with MTA. Setting of these materials in the presence of citric acid enhanced DPSC viability and adherence.

Interaction of dental pulp stem cells with Biodentine and MTA after exposure to different environments

ABSTRACT Objective: The aim of the present study was to evaluate and compare the cytotoxic effects of Biodentine and MTA on dental pulp stem cells (DPSCs) and to assess cell viability and adherence after material exposure to an acidic environment. Material and Methods: DPSCs were cultured either alone or in contact with either: Biodentine; MTA set for 1 hour; or MTA set for 24 hours. After 4 and 7 days, cell viability was measured using the MTT assay. Biodentine and MTA were also prepared and packed into standardized bovine dentin disks and divided into three groups according to the storage media (n=6/group): freshly mixed materials without storage medium (Group A); materials stored in saline (Group B); materials stored in citric acid buffered at pH 5.4 (Group C). After 24 hours, DPSCs were introduced in the wells and cell adherence, viability, and cellular morphology were observed via confocal microscopy after three days of culture. Cell viability was analyzed using repeated-measures analysis of variance test with Tukey's post hoc tests (α=0.05). Results: Biodentine expressed significantly higher cell viability compared with all other groups after 4 days, with no differences after 7 days. Notably, cell viability was significantly greater in 24-hour set MTA compared with 1-hour set MTA and control groups after 7 days. Material exposure to an acidic environment showed an increase in cell adherence and viability in both groups. Conclusions: Biodentine induced a significantly accelerated cell proliferation compared with MTA. Setting of these materials in the presence of citric acid enhanced DPSC viability and adherence.

Comparison of Bacterial Community Composition of Primary and Persistent Endodontic Infections Using Pyrosequencing.

INTRODUCTION: Elucidating the microbial ecology of endodontic infections (EIs) is a necessary step in developing effective intracanal antimicrobials. The aim of the present study was to investigate the bacterial composition of symptomatic and asymptomatic primary and persistent infections in a Greek population using high-throughput sequencing methods. METHODS: 16S amplicon pyrosequencing of 48 root canal bacterial samples was conducted, and sequencing data were analyzed using an oral microbiome-specific and a generic (Greengenes) database. Bacterial abundance and diversity were examined by EI type (primary or persistent), and statistical analysis was performed by using non-parametric and parametric tests accounting for clustered data. RESULTS: Bacteroidetes was the most abundant phylum in both infection groups. Significant, albeit weak associations of bacterial diversity were found, as measured by UniFrac distances with infection type (analyses of similarity, R = 0.087, P = .005) and symptoms (analyses of similarity, R = 0.055, P = .047). Persistent infections were significantly enriched for Proteobacteria and Tenericutes compared with primary ones; at the genus level, significant differences were noted for 14 taxa, including increased enrichment of persistent infections for Lactobacillus, Streptococcus, and Sphingomonas. More but less abundant phyla were identified using the Greengenes database; among those, Cyanobacteria (0.018%) and Acidobacteria (0.007%) were significantly enriched among persistent infections. Persistent infections showed higher phylogenetic diversity (PD) (asymptomatic: PD = 9.2, standard error [SE] = 1.3; symptomatic: PD = 8.2, SE = 0.7) compared with primary infections (asymptomatic: PD = 5.9, SE = 0.8; symptomatic: PD = 7.4, SE = 1.0). CONCLUSIONS: The present study revealed a high bacterial diversity of EI and suggests that persistent infections may have more diverse bacterial communities than primary infections.