Lactobacillus plantarum lipoteichoic acid disrupts mature Enterococcus faecalis biofilm.

Apical periodontitis is caused by biofilm-mediated root canal infection. Early phase oral bacterial biofilms are inhibited by Lactobacillus plantarum lipoteichoic acid (Lp.LTA). However, mature biofilms that develop over 3 weeks are more resistant to traditional endodontic medicaments. Therefore, this study examined the effectiveness of Lp.LTA on disrupting mature Enterococcus faecalis biofilms, and on enhancing the effects of endodontic medicaments. LTA was purified from L. plantarum through butanol extraction followed by hydrophobic and ion-exchange chromatography. E. faecalis biofilms were formed over 3 weeks on glass bottom dishes and in dentin blocks obtained from human single-rooted premolars. These mature biofilms were treated with or without Lp.LTA for 1 h, followed by additional treatment with either chlorhexidine digluconate (CHX), calcium hydroxide (CH), or triple antibiotics for 24 h. Biofilms on glass were live/dead stained and quantified by ZEN through confocal laser microscopy. Bio-films in dentin were fixed, sputter coated and analyzed by ImageJ with scanning electron microscopy. Preformed E. faecalis mature biofilms on the culture dishes were dose-dependently disrupted by Lp.LTA. Lp.LTA potentiated the effects of CHX or CH on the disruption of mature biofilm. Interestingly, CHX-induced disruption of preformed E. faecalis mature biofilms was synergistically enhanced only when pre-treated with Lp.LTA. Furthermore, in the dentin block model, Lp.LTA alone reduced E. faecalis mature biofilm and pre-treatment with Lp.LTA promoted the anti-biofilm activity of CHX. Lp.LTA could be an anti-biofilm or supplementary agent that can be effective for E. faecalis-biofilm-induced diseases.

Antimicrobial Efficacy of a Novel Antibiotic-Eluting Injectable Platelet-Rich Fibrin Scaffold against a Dual-Species Biofilm in an Infected Immature Root Canal Model.

BACKGROUND AND AIMS: This study was aimed at evaluating the antibacterial property of an injectable platelet-rich fibrin (I-PRF) scaffold containing triple antibiotic mixture against an Actinomyces naeslundii (A. naeslundii) and Enterococcus faecalis (E. faecalis) biofilm in an infected immature root canal model. METHODS: A dual-species biofilm was inoculated inside the root canals via a series of centrifugal cycles. The samples were allocated to three experimental groups (i.e., G1: triple antibiotic mixture, G2: I-PRF containing triple antibiotic mixture, and G3: antibiotic-free I-PRF scaffold) and two control groups (G4: seven-day biofilm untreated and G5: bacteria-free untreated). RESULTS: Bacterial gene quantification change and the overall reduction of live bacteria were evaluated. The highest antibacterial activity against A. naeslundii belonged to G2. However, G1 and G2 had similar antibacterial property against E. faecalis (p value = 0.814). In general, experimental groups revealed higher levels of antibacterial activity against E. faecalis than against A. naeslundii (p value < 0.001). Notably, G2 could dramatically decrease the number of live bacteria up to near 92%. CONCLUSIONS: The current study provides insight into the antibacterial property of an antibiotic-eluting I-PRF scaffold against a dual-species biofilm colonized inside the root canal. The fabricated scaffold contains not only the antibiotics but also the growth factors, which favor the regeneration.

Polyamines and microbiota in bicuspid and tricuspid aortic valve aortopathy.

Polyamines are small aliphatic cationic molecules synthesized via a highly regulated pathway and involved in general molecular and cellular phenomena. Both mammalian cells and microorganisms synthesize polyamines, and both sources may contribute to the presence of polyamines in the circulation. The dominant location for microorganisms within the body is the gut. Accordingly, the gut microbiota probably synthesizes most of the polyamines in the circulation in addition to those produced by the mammalian host cells. Polyamines are mandatory for cellular growth and proliferation. Established evidence suggests that the polyamine spermidine prolongs lifespan and improves cardiovascular health in animal models and humans through both local mechanisms, involving improved cardiomyocyte function, and systemic mechanisms, including increased NO bioavailability and reduced systemic inflammation. Higher levels of polyamines have been detected in non-dilated aorta of patients affected by bicuspid aortic valve congenital malformation, an aortopathy associated with an increased risk for thoracic ascending aorta aneurysm. In this review, we discuss metabolism of polyamines and their potential effects on vascular smooth muscle and endothelial cell function in vascular pathology of the thoracic ascending aorta associated with bicuspid or tricuspid aortic valve.

Reverse rotary instrumentation in the apical third of the root canal system: An scanning electron microscope analysis.

AIMS: The aim of the present study was to evaluate the efficacy of reverse rotary instrumentation in disinfection of the root canal at the apical third and qualitative confirmatory analysis using the scanning electron microscope (SEM). SUBJECTS AND METHODS: Sixty single-rooted mandibular premolars were instrumented up to Protaper rotary file size F2 and contaminated with a known species of Enterococcus faecalis (ATCC 29212). The samples were then divided into three groups; Group 1: Experimental group-irrigation by agitation of 1% NaOCl with reverse rotary instrumentation; Group 2: Negative control-no irrigation; and Group 3 positive control-irrigation with 1% NaOCl using a 30-gauge needle. The colony forming units of all the groups were checked. SEM analysis of the samples was focused on the apical third to confirm the absence of E. faecalis biofilms. The data obtained were statistically analyzed by the Fisher's exact test and Pearson's Chi-square test. RESULTS: Group I and III showed significant reduction in the growth of E. faecalis (P ≤ 0.001). SEM confirmed dense bacterial colonies in the Group II consistent with biofilm formation and reduction in bacterial colonies in Group I and II. CONCLUSION: Agitation with reverse rotary instrumentation in the apical third of the root canal along with 1% sodium hypochlorite proved effective in disinfection of the apical third of the root canal, which was further confirmed by scanning electron microscopic analysis. Hence, it can be used as an adjunct during rotary instrumentation in efficient cleansing of the root canal system in the apical third of the root canal system.

The evaluation of the transport medium for extracted premolars prior to cryopreservation: an in vitro study.

Autotransplantation is a versatile technique for the replacement of a missing tooth and cryopreservation can expand its scope. The aim of this in vitro study is to compare the antimicrobial effect of different transport protocols on procured teeth prior to cryopreservation. Streptococcus oralis biofilms were grown on ten sterile premolars, incubated for 48 h and subjected to the following transport procedures: an untreated (contaminated) control group, a group rinsed with phosphate buffered saline (PBS), a group transported in PBS, a group transported in Dulbecco's Modified Eagle's medium (DMEM) supplemented with fetal calf serum (FCS), and a group transported in DMEM supplemented with FCS and antibiotics (AB). The effect of cryopreservation as such, as well as the combination with a transport medium (DMEM + FCS + AB) on the contamination was also tested. The surviving bacteria were harvested, and determined by plate counting. There was no significant reduction in contamination after rinsing the tooth, after transport in PBS or after transport in DMEM with FCS. Significant reductions were observed for transport in DMEM with AB when compared to the control group (p = 0.003). Cryopreservation as such reduced the biofilm significantly (p < 0.001). No cumulative effect could be found when transport in DMEM + FCS + AB was followed by cryopreservation. Within the limitations of this laboratory set-up, DMEM + FCS + AB was the most effective transport medium in S. oralis biofilm elimination. It could not be concluded that rinsing of the tooth gives an additional reduction. Cryopreservation as such decontaminated the teeth more effectively than any tested transport procedure.

The evaluation of the transport medium for extracted premolars prior to cryopreservation: a systematic literature review.

Prior to cryopreservation, a tooth is transported from a contaminated oral environment to the tooth bank. Our objective was to identify all studies reporting or investigating a transport protocol prior to the cryopreservation of teeth, in terms of decontamination of the subjects. The systematic literature search (1970-2017) was based on MEDLINE via PubMed, Web of Science and the Cochrane Library. The reference lists of the included studies and the Science Citation Index were used for hand searching (snowballing). Only studies reporting the transport conditions of the transplant were included. Language restrictions for English, Dutch or French were applied. The search led to 14 eligible studies. Almost all studies were laboratory studies, so the methodological quality of evidence was low. The majority of the included studies was performed by only five different research groups and the number of subjects varied between 1 and 120 teeth. In general, the teeth were stored in a tissue culture medium supplemented with fetal calf serum and/or different combinations of antibiotics and/or antimycotics. The teeth were transported cooled (4 °C) or at room temperature, for a period of time not exceeding 24 h. Only three studies reported the irrigation of the teeth with phosphate buffered saline prior to the transport. The optimisation of the decontamination during transport was investigated in three studies (from 1971, 1980 and 1982). It was concluded that the literature on this topic is scarce, and the decontamination protocol for teeth, prior to cryopreservation has not been validated recently.

A colourimetric evaluation of the effect of bacterial contamination on teeth stained with blood in vitro: Evaluation of the efficacy of two different bleaching regimes.

BACKGROUND: Tooth discolouration could occur due to bacterial contamination in traumatized teeth. Hydrogen peroxide is the commonly used bleaching agent. However, due to concerns over safety, alternative bleaching regimes such as sodium perborate (S) and thiourea-hydrogen peroxide (T) have been investigated. METHODS: Apices resected and pulp extirpated 99 premolars were divided into two groups. Group 1 and 2 was injected with blood and blood/bacteria, stored anaerobically for 35 days. The two groups were treated by bleaching with water, S or T. Teeth were rebleached after 7 days. Colourimetric evaluation was assessed using digital imaging, CasMatch standardization and CIE L*a*b colour system preoperatively, 35 days of staining and 7 and 14 of bleaching. A linear mixed model with fixed effects of time, group and bleach was used to examine colour difference. RESULTS: Blood-stained teeth were significantly redder and darker on day 35 compared with blood/bacteria-stained teeth. After bleaching, blood-stained teeth retained significant redness compared with blood/bacteria-stained teeth using either S or T. T produced a significantly whiter shade in both the groups after 14 days. CONCLUSIONS: Blood-stained teeth were significantly darker and red compared with blood/bacteria-stained teeth. T bleaching regime was more effective than S.

Tooth bleaching with low-temperature plasma lowers surface roughness and Streptococcus mutans adhesion.

AIM: To evaluate the structural-morphological changes in enamel surface roughness and Streptococcus mutans adhesion after tooth bleaching using plasma in combination with a low concentration of 15% carbamide peroxide (CP). METHODOLOGY: Sixty pairs of premolars were randomly assigned to the treatment groups (n = 30; buccal surface, groups 1A/2A) or controls (n = 30; palatal surface, Groups 1B/2B). Group 1A received a low concentration of 15% CP and low-temperature plasma. Premolars in group 1B were placed in phosphate-buffered saline and served as controls. The buccal surface of Groups 2A was subjected to 15% CP alone, whilst the palatal surface was subsequently immersed in PBS (group 2B). After bleaching, all teeth were soaked for 1 h in artificial saliva at 37 °C. Subsequently, teeth were placed in brain-heart infusion with S. mutans at 37 °C for 24 h. The assessment of the structural-morphological changes was carried out using a biofilm assay, scanning electron microscopy and atomic force microscopy. Statistical analysis of the data was performed with the SPSS (SPSS Inc., Version 18.0, Chicago, IL, USA). The Student's t-test was used to determine whether there was a significant difference in the structural-morphological effects with and without plasma. RESULTS: Significantly less S. mutans adhesion was observed in group 1A compared with the other groups (P < 0.05). Moreover, the surface roughness was significantly greater in group 2A compared with the other groups (P < 0.05). CONCLUSIONS: The application of plasma did not result in any structural-morphological and topographic changes in the enamel. The combined bleaching method using plasma and a low concentration of 15% CP was less destructive, particularly with respect to tooth surface changes.

Disinfection of dentinal tubules with 2% Chlorhexidine gel, Calcium hydroxide and herbal intracanal medicaments against Enterococcus faecalis: An in-vitro study.

AIM: This in vitro study was conducted to evaluate the disinfection of dentinal tubules using 2% Chlorhexidine gel, Honey, Aloe vera gel, Curcuma longa, Propolis gel and Calcium hydroxide against Enterococcus faecalis. MATERIALS AND METHOD: Two hundred and ten human mandibular first premolars were infected with Enterococcus faecalis for 21 days. Samples were divided into 7 groups. Group I- Saline (negative control), Group II- 2% Chlorhexidine gel(CHX), Group III- honey, Group IV- Aloe vera gel, Group V- 20% Curcuma longa gel, Group VI- Propolis gel and Group VII -Calcium hydroxide (CH). At the end of 1, 3 and 5 days, the antimicrobial efficacy of medicaments against E.faecalis was assessed at the depths of 200µm and 400µm. RESULTS: 2% Chlorhexidine gel was most effective followed by Propolis and Curcuma longa. CONCLUSION: 2% Chlorhexidine gel gave the best results. Among the herbal extracts Propolis and Curcuma longa hold a promising future but to implement their use as sole intracanal medicaments clinically, further in vivo and long term studies are warranted.

Effectiveness of photodynamic therapy associated with irrigants over two biofilm models.

BACKGROUND: This study aimed to evaluate the antibacterial effect and the biofilm disruption promoted by antimicrobial photodynamic therapy (aPDT) associated with sodium hypochlorite (NaOCl) and chlorexidine (CHX) over monospecies and multispecies biofilms. METHODS: In monospecies model, forty-six premolars were inoculated with Enterococcus faecalis for 21days and divided into three groups: saline, CHX and NaOCl. After irrigation, aPDT was performed. Samples were collected at baseline (S1) and after irrigation (S2) and aPDT (S3). Colony-forming unit (CFU) counts were performed. In multispecies model, sixty bovine dentin blocks were infected intraorally for 72h and divided into six groups: saline, saline/aPDT, CHX, CHX/aPDT, NaOCl and NaOCl/aPDT. The percentage and the biovolume of live cells and the total biovolume were assessed using confocal laser scanning microscopy. RESULTS: CHX and NaOCl showed the lowest CFU counts (P<0.05). aPDT reduced the bacterial counts in saline (S2-S3; P<0.05). The lowest amount of live cells was observed in CHX, CHX/aPDT, NaOCl and NaOCl/aPDT. aPDT did not reduce the total biovolume (P>0.05). CONCLUSION: aPDT associated with saline reduced the bacterial load in root canals infected with E. faecalis. aPDT did not reduce the total biovolume in situ; however, the irrigant was decisive to disrupt multispecies biofilms.

Influence of Smear Layer on the Antimicrobial Activity of a Sodium Hypochlorite/Etidronic Acid Irrigating Solution in Infected Dentin.

INTRODUCTION: The aim of this study was to evaluate the influence of the smear layer on the antimicrobial activity of a 2.5% sodium hypochlorite (NaOCl)/9% etidronic acid (HEBP) irrigating solution against bacteria growing inside dentin tubules. METHODS: Dentin tubules were infected with Enterococcus faecalis by centrifugation. After 5 days of incubation, the smear layer had formed in half of the samples, which were then treated with 2.5% NaOCl either alone or combined with 9% HEBP for 3 minutes. The percentage of dead cells in infected dentinal tubules was measured using confocal laser scanning microscopy and the live/dead technique. The smear layer on the surface of the root canal wall was also observed by scanning electron microscopy. Results of the percentage of dead cells were compared using parametric tests after subjecting data to the normalized Anscombe transformation. The level of significance was P < .05. RESULTS: In the absence of the smear layer, 2.5% NaOCl alone and combined with 9% HEBP showed high antimicrobial activity without significant differences between the 2. The smear layer reduced the antimicrobial activity of 2.5% NaOCl significantly, whereas the solution with HEBP was not affected. No dentin tubules free of the smear layer were obtained in the 2.5% NaOCl group. In the case of 2.5% NaOCl/9% HEBP, 95.40% ± 3.63% of dentin tubules were cleaned. CONCLUSIONS: The presence of the smear layer reduced the antimicrobial activity of 2.5% NaOCl. The combination of 2.5% NaOCl/9% HEBP exerted antimicrobial activity that was not reduced by the smear layer.

Effect of photodynamic therapy with two photosensitizers on Streptococcus mutants: In vitro study.

BACKGROUND AND OBJECTIVES: Streptococcus mutans (S. mutans) colonizes the oral cavity and causes dental caries and periodontal diseases. Considering the importance of the treatments that decrease pathogenic microorganisms, the aim of the present research was the assessment of the antimicrobial effect of Photodynamic Therapy (PDT) with Methylene Blue (MB) and Indocyanine Green (IG) photosensitizers on S. mutans. MATERIALS AND METHODS: In this In vitro experimental study, Sixty four caries-free first premolars were contaminated with 0.5 McFarland S.mutans suspension and were randomly assigned to 4 groups. The teeth in the first group were impregnated with 2% MB while the teeth in the second group were impregnated with 0.2% IG. The teeth in the first group were irradiated with continuous-wave 660nm dod laser with 40mw output power, energy density of 2.4J/cm2 and 100% duty cycle for 60s, while the teeth in the second group were irradiated with continuous -wave 810nm diode laser with 100mw out power, density energy of 6J/cm2 and 100% duty cycle for 60s in contact mode. In the third group, the teeth were suspended in 0.2% Chlorhexidine for 30s. The fourth group was considered as the control. The teeth were sampled before and after the interventions and the samples were incubated in Blood Agar for 24h. Afterwards, the number of S. mutans colonies were counted. Data were statistically analyzed by Kruskal-Wallis, Dunn's and Friedman tests. RESULTS: In the groups treated with a combination of MB and IG and laser irradiation and also in the Chlorhexidine group, the final number of S. mutans colonies equaled zero. In "MB and IG groups without laser irradiation", although the amount of microorganisms decreased, but the number of colonies did not reach zero. Pair comparisons by Dunn's test showed that there was a significant difference between "MB and IG groups without laser irradiation" and the other experimental groups p=0.03). CONCLUSION: PDT with MB and IG photosensitizers and also Chlorhexidine mouthwash, have the ability to completely eradicate S. mutans bacterial colonies.

Efficacy of 4 Irrigation Protocols in Killing Bacteria Colonized in Dentinal Tubules Examined by a Novel Confocal Laser Scanning Microscope Analysis.

INTRODUCTION: The aim of this study was to determine the efficiency of 4 irrigation systems in eliminating bacteria in root canals, particularly in dentinal tubules. METHODS: Roots of human teeth were prepared to 25/04, autoclaved, and inoculated with Enterococcus faecalis for 3 weeks. Canals were then disinfected by (1) standard needle irrigation, (2) sonically agitating with EndoActivator, (3) XP Endo finisher, or (4) erbium:yttrium aluminum garnet laser (PIPS) (15 roots/group). The bacterial reduction in the canal was determined by MTT assays. For measuring live versus dead bacteria in the dentinal tubules (4 teeth/group), teeth were split open and stained with LIVE/DEAD BackLight. Coronal, middle, and apical thirds of the canal dentin were scanned by using a confocal laser scanning microscope (CLSM) to determine the ratio of dead/total bacteria in the dentinal tubules at various depths. RESULTS: All 4 irrigation protocols significantly eliminated bacteria in the canal, ranging from 89.6% to 98.2% reduction (P < .001). XP Endo had the greatest bacterial reduction compared with other 3 techniques (P < .05). CLSM analysis showed that XP Endo had the highest level of dead bacteria in the coronal, middle, and apical segments at 50-µm depth. On the other hand, PIPS had the greatest bacterial killing efficiency at the 150-µm depth in all 3 root segments. CONCLUSIONS: XP Endo appears to be more efficient than other 3 techniques in disinfecting the main canal space and up to 50 µm deep into the dentinal tubules. PIPS appears to be most effective in killing the bacteria deep in the dentinal tubules.

A Comparison of Apical Bacterial Extrusion in Manual, ProTaper Rotary, and One Shape Rotary Instrumentation Techniques.

INTRODUCTION: Apical extrusion of irrigants and debris is an inherent limitation associated with cleaning and shaping of root canals and has been studied extensively because of its clinical relevance as a cause of flare-ups. Many factors affect the amount of extruded intracanal materials. The purpose of this study was to assess the bacterial extrusion by using manual, multiple-file continuous rotary system (ProTaper) and single-file continuous rotary system (One Shape). METHODS: Forty-two human mandibular premolars were inoculated with Enterococcus faecalis by using a bacterial extrusion model. The teeth were divided into 3 experimental groups (n = 12) and 1 control group (n = 6). The root canals of experimental groups were instrumented according to the manufacturers' instructions by using manual technique, ProTaper rotary system, or One Shape rotary system. Sterilized saline was used as an irrigant, and bacterial extrusion was quantified as colony-forming units/milliliter. The results obtained were statistically analyzed by using one-way analysis of variance for intergroup comparison and post hoc Tukey test for pair-wise comparison. The level for accepting statistical significance was set at P < .05. RESULTS: All the instrumentation techniques resulted in bacterial extrusion, with manual step-back technique exhibiting significantly more bacterial extrusion than the engine-driven systems. Of the 2 engine-driven systems, ProTaper rotary extruded significantly more bacteria than One Shape rotary system (P < .05). CONCLUSIONS: The engine-driven nickel-titanium systems were associated with less apical extrusion. The instrument design may play a role in amount of extrusion.

Antibacterial activity of chlorhexidine after final irrigation with ethanol: CLSM and culture-based method analysis.

This study investigated the effect of 95% ethanol on the antibacterial properties of 2% chlorexidine (CHX) over monospecies biofilm (Enterococcus faecalis) through a culture-based method, and over multispecies biofilm using confocal laser scanning microscopy (CLSM). For monospecies model, E. faecalis biofilm was induced in 40 root canals. The irrigation procedures were: S-saline solution; S/CHX-saline solution + CHX; E-ethanol; and E/CHX-ethanol + CHX. Microbial sampling was performed at three periods: before (S1), immediately after (S2), and 72 h after the final flush (S3). For multispecies biofilm model, 28 sterilized bovine dentin blocks were fixed on a removable orthodontic device to allow intraoral biofilm development. Seven samples were used in each group. Statistical analysis was carried out by using the Kruskal-Wallis test and Dunn's test for multiple comparisons. There was a significant reduction in CFUs count immediately after the final flush (S2) in all experimental groups (P < 0.05). However, only S/CHX, E and E/CHX groups had CFU counts close to zero, without differences among them (P > 0.05). After 72h (S3), the S/CHX and E/CHX groups had CFU counts near zero (P > 0.05). The CFU count increased in S3 for S and E groups (P < 0.05). CLSM showed that the percentages of remaining live cells were similar in S/CHX, E, and E/CHX groups (P > 0.05). The S group had the highest percentage of live cells (P < 0.05). The 95% ethanol did not interfere in the antibacterial properties of 2% CHX over mono- and multispecies biofilms.

Bioactivity Studies of ß-Lactam Derived Polycyclic Fused Pyrroli-Dine/Pyrrolizidine Derivatives in Dentistry: In Vitro, In Vivo and In Silico Studies.

The antibacterial activity of ß-lactam derived polycyclic fused pyrrolidine/pyrrolizidine derivatives synthesized by 1, 3-dipolar cycloaddition reaction was evaluated against microbes involved in dental infection. Fifteen compounds were screened; among them compound 3 showed efficient antibacterial activity in an ex vivo dentinal tubule model and in vivo mice infectious model. In silico docking studies showed greater affinity to penicillin binding protein. Cell damage was observed under Scanning Electron Microscopy (SEM) which was further proved by Confocal Laser Scanning Microscope (CLSM) and quantified using Flow Cytometry by PI up-take. Compound 3 treated E. faecalis showed ROS generation and loss of membrane integrity was quantified by flow cytometry. Compound 3 was also found to be active against resistant E. faecalis strains isolated from failed root canal treatment cases. Further, compound 3 was found to be hemocompatible, not cytotoxic to normal mammalian NIH 3T3 cells and non mutagenic. It was concluded that ß-lactam compound 3 exhibited promising antibacterial activity against E. faecalis involved in root canal infections and the mechanism of action was deciphered. The results of this research can be further implicated in the development of potent antibacterial medicaments with applications in dentistry.

Apical extrusion of Enterococcus faecalis using three different rotary instrumentation techniques: an in vitro study.

AIMS: To compare the apical extrusion of Enterococcus faecalis after instrumentation with three different Ni-Ti rotary instruments- An in vitro study. SETTINGS AND DESIGN: In vitro study Methods and Material: Forty freshly extracted mandibular premolars were mounted in bacteria collection apparatus and root canals were contaminated with a suspension of Enterococcus faecalis. The contaminated teeth were divided into 4 groups of 10 teeth each according to rotary system used for instrumentation: Group1: Hyflex files, Group 2: GTX files, Group 3: Protaper files and Group 4: control group (no instrumentation). Bacteria extruded after preparations were collected into vials and microbiological samples were incubated in BHI broth for 24 hrs. The colony forming units were determined for each sample. STATISTICAL ANALYSIS USED: Statistical analysis was done using one way ANOVA followed by post hoc independent " t" test. RESULTS: GTX files extruded least amount of bacteria followed by Hyflex files. Maximum extrusion of E. faecalis was seen in rotary Protaper group. CONCLUSION: Least amount of extrusion was seen with GTX files followed by Hyflex files and then rotary Protaper system.

Efficacy of 3D conforming nickel titanium rotary instruments in eliminating canal wall bacteria from oval-shaped root canals.

OBJECTIVES: To evaluate the effectiveness of TRUShape® 3D Conforming Files, compared with Twisted Files, in reducing bacteria load from root canal walls, in the presence or absence of irrigant agitation. METHODS: Extracted human premolars with single oval-shaped canals were infected with Enterococcus faecalis. Teeth in Group I (N=10; NaOCl and QMix® 2in1 as respective initial and final irrigants) were subdivided into 4 subgroups: (A) TRUShape® instrumentation without irrigant activation; (B) TRUShape® instrumentation with sonic irrigant agitation; (C) Twisted Files without irrigant agitation; (D) Twisted Files with sonic irrigant agitation. To remove confounding factor (antimicrobial irrigants), teeth in Group II (N=10) were irrigated with sterile saline, using the same subgroup designations. Specimens before and after chemomechanical débridement were cultured for quantification of colony-forming units (CFUs). Data from each group were analyzed separately using two-factor ANOVA and Holm-Sidak multiple comparison (α=0.05). Canal wall bacteria were qualitatively examined using scanning electron microscopy (SEM) and light microscopy of Taylor-modified Brown and Brenn-stained demineralised sections. RESULTS: CFUs from subgroups in Group I were not significantly different (P=0.935). For Group II, both file type (P<0.001) and irrigant agitation (P<0.001) significantly affected log-reduction in CFU concentrations. The interaction of these two factors was not significant (P=0.601). Although SEM showed reduced canal wall bacteria, bacteria were present within dentinal tubules after rotary instrumentation, as revealed by light microscopy of longitudinal root sections. CONCLUSIONS: TRUShape® files removed significantly more canal wall bacteria than Twisted Files when used without an antibacterial irrigant; the latter is required to decontaminate dentinal tubules. CLINICAL SIGNIFICANCE: Root canal disinfection should not be focused only on a mechanistic approach. Rather, the rational choice of a rotary instrumentation system should be combined with the use of well-tested antimicrobial irrigants and delivery/agitation techniques to establish a clinically realistic chemomechanical débridement protocol.

Periapical inflammation subsequent to coronal inoculation of dog teeth root filled with resilon/epiphany in 1 or 2 treatment sessions with chlorhexidine medication.

INTRODUCTION: Therapeutic methods that inhibit microbial ingress into filled root canals are desirable. This in vivo study assessed the inhibition of periapical inflammation subsequent to coronal inoculation in canals medicated with 2% chlorhexidine gel and filled with Resilon/Epiphany (Pentron Clinical Technologies, Wallingford, CT). METHODS: Six Beagle dogs each had 10 two-rooted premolars treated. In group 1 (n = 36 roots), 1 root/tooth had the canal conditioned with Primer Epiphany, filled with Epiphany sealer and Resilon core in 1 session, and coronally sealed with PhotacFil. In group 2 (n = 36 roots), the second root/tooth had the canal medicated with 2% chlorhexidine gel for 1 week and then filled and coronally sealed as in group 1. After 3 weeks, canals were exposed to the oral environment for 7 days, inoculated with isologous plaque, and coronally sealed. Negative controls treated as groups 1 and 2 remained sealed. Positive controls had canals unfilled and exposed. Seven months after inoculation, dogs were euthanized; jaw blocks processed for histologic examination; and periapical inflammation (PI) recorded as none, mild, or severe. RESULTS: In groups 1 and 2, severe PI occurred in 5 of 65 roots (8%) and mild PI in 18 of 65 roots (28%) with a significantly higher (P = .031) PI incidence in group 2 than in group 1. Negative controls had only mild PI in 9 of 29 roots (31%). Roots medicated with 2% chlorhexidine gel had mild PI significantly more (P = .009) than roots filled in 1 session (more than 2-fold). CONCLUSIONS: Intracanal medication with 2% chlorhexidine gel and root filling with Resilon/Epiphany did not effectively inhibit apical periodontitis subsequent to coronal inoculation.

Antibacterial action of Chlorhexidine/thymol containing varnishes in vitro and in vivo.

OBJECTIVES: The antibacterial activity of two different formulations of a chlorhexidine/thymol varnish should be elucidated in vitro and in vivo. METHODS: The agar diffusion assay with Cervitec(®) and CervitecPlus(®) and three reference strains each of streptococci, lactobacilli, actinomyces and periodontal pathogens was performed. In a split-mouth study, 40 volunteers applied the test (CervitecPlus(®), solvent water and ethanol) and control (Cervitec(®), solvent ethyl acetate) varnish at buccal recessions of premolar teeth at baseline as well as after two, four and seven days. Supra- and subgingival plaques were collected 2 weeks before baseline and at the screening appointments. Supragingival plaque was analysed for mutans streptococci and lactobacilli and subgingival samples for Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis and Porphyromonas intermedia. Friedman/Wilcoxon tests and U-test were used for statistical analysis (P < 0.05). RESULTS: Most reference strains were susceptible with inhibition zones (mm) as follows: Cervitec(®)/CervitecPlus(®) streptococci 27 ± 1.7/21.3 ± 2.5, lactobacilli 26 ± 9.2/23.7 ± 4.9, actinomyces 36.3 ± 6.6/27.3 ± 1.5, periodontal pathogens 18.7 ± 7.6/18 ± 1.7. Both varnishes reduced significantly the counts of mutans streptococci and lactobacilli in the patients. However, no significant differences were found between test and control sides at any time. The total counts of periodontal pathogens were low. A tendency to higher counts of A. actinomycetemcomitans at the control side could be shown; the test side did not harbour significantly higher counts. CONCLUSION: Both varnishes may influence the plaque formation and reduce mutans streptococci in supragingival plaque.