Andre Mickel

Antimicrobial activity of endodontic sealers on Enterococcus faecalis.

Enterococcus faecalis has been shown to be highly resistant once established in the root canal system and may play an important role in endodontic failures. The purpose of this study was to evaluate the antimicrobial activity of four root canal sealers on E. faecalis. Seventeen blood-agar plates were inoculated with E. faecalis using the Lawn technique. Five discs were placed on each plate, four with sealers--Sealapex, Roth 811, Kerr EWT, and AH-Plus--and an ampicillin disc as the control. The plates were incubated at 37 degrees C. The zones of inhibition were measured at 24 and 48 h. Analysis using a one-way ANOVA and Tukey test showed a statistically significance difference (p < 0.05) between all four groups of sealers. Roth 811 showed the largest zone of inhibition (1.1 mm), followed by Sealapex (0.8 mm) and Kerr EWT (0.5 mm), whereas AH-Plus had no antimicrobial activity. There was no difference in the zones of inhibition between the 24- and 48-h time periods.

Effectiveness of Selected Materials Against Enterococcus faecalis: Part 3. The Antibacterial Effect of Calcium Hydroxide and Chlorhexidine on Enterococcus faecalis

It has been found that Enterococcus faecalis is most commonly isolated in failed endodontic treatment. Irrigation with chlorhexidine gluconate has been suggested based on its antimicrobial effect and substantivity. Calcium hydroxide also is an effective antimicrobial agent because of its high alkalinity. The purpose of this study was to test the individual and combined effect of calcium hydroxide and chlorhexidine against E. faecalis. The agar-diffusion test was performed on Mueller-Hinton plates. Paper disks were impregnated with: (a) CaOH powder with sterile water; (b) Pulpdent; (c) 0.12% Peridex; (d) CaOH powder with Peridex; and (e) Pulpdent with Peridex. Ampicillin served as a control. The plates were incubated at 37 degrees C for 72 h. Peridex showed significantly larger zones of inhibition compared with CaOH. No statistically significant difference was found between Peridex and the combination of CaOH and Peridex.

Genetic Predisposition to Persistent Apical Periodontitis

INTRODUCTION The proinflammatory cytokine interleukin (IL)-1 is a key regulator of host responses to microbial infection and a major modulator of extracellular matrix catabolism and bone resorption. Allele2 of IL-1β is associated with a four-fold increase in IL-1β production. The aim of this case-control study was to evaluate the gene polymorphism of IL-1β in the pathogenesis of endodontic failure. We hypothesized that the gene polymorphism (allele2 of IL-1β) would influence host response and enhance inflammatory reactions predisposing to persistent apical periodontitis (PAP). MATERIALS AND METHODS Subjects with at least 1 year of follow-up after root canal therapy (RCT) were recalled. Inclusion and exclusion criteria were applied, and 34 subjects with signs/symptoms of PAP with otherwise acceptable RCT were included. Sixty-one controls showed healing with acceptable RCT. Genomic DNA from buccal mucosa was amplified by polymerase chain reaction followed by restriction fragment length polymorphism to distinguish the alleles of IL-1β gene polymorphism. RESULTS A significant difference in the distribution of the polymorphic genotype among cases (70.6%) and controls (24.6%) (P < .001, Pearson χ(2)) was shown. CONCLUSIONS These findings suggest that specific genetic markers associated with increased IL-1β production may contribute to increased susceptibility to PAP.

Molecular Analysis of Persistent Periradicular Lesions and Root Ends Reveals a Diverse Microbial Profile

INTRODUCTION The microbial etiology of periradicular lesions is recognized; however, the bacterial profile of these lesions is not well elucidated. The purpose of this study was to determine the frequency of bacterial colonization in these lesions and to characterize the bacterial community present in root ends and periradicular lesions. METHODS Thirty-four adult patients who presented for apicoectomy of persistent periradicular lesions after endodontic therapy were selected for the study and samples of periradicular tissue and resected root ends collected. Total bacterial levels were estimated for 34 paired periradicular lesions and root ends using real-time polymerase chain reaction with universal bacterial primers. Sixteen pairs of these samples were analyzed using ribosomal 16S cloning and sequencing for bacterial identification. RESULTS Bacteria were detected more consistently and at higher levels in root ends. Periradicular lesions exhibited a diverse microbial profile with many uncultivated phylotypes. Enterococcus faecalis and Burkholderia cepacia predominated in both samples. Campylobacter gracilis and Streptococcus gordonii were associated with root ends, whereas Atopobium rimae, Peptostreptococcus micros, Streptococcus genomospecies C8, Dialister sp E2_20 E1, and Eubacterium strain A35MT were associated with periradicular lesions. CONCLUSIONS Persistent periradicular lesions are polymicrobial infections with many as-yet-uncultivated and unknown bacterial species. The bacterial load and microbial profile of root ends is significantly different from the soft-tissue lesion, indicating the presence of diverse bacterial populations in these tissues.

A Comparison of the Cytotoxicity and Proinflammatory Cytokine Production of EndoSequence Root Repair Material and ProRoot Mineral Trioxide Aggregate in Human Osteoblast Cell Culture Using Reverse-Transcriptase Polymerase Chain Reaction

INTRODUCTION The purpose of this study was to compare the cytotoxicity and cytokine expression profiles of EndoSequence Root Repair Material (ERRM; Brasseler, Savannah, GA) putty, ERRM flowable, and ProRoot mineral trioxide aggregate (MTA; Dentsply Tulsa Dental, Johnson City, TN) using osteoblast cells (MG-63). METHODS Four millimeters in diameter of each material was placed in the center of a 6-well culture plate, and a 2-mL suspension (10(5) cells/mL) of human osteoblasts was seeded in each well. Photomicrograph images were used to evaluate cytotoxicity as evidenced by the lack of osteoblast cell growth in relation to the materials with AH-26 (Dentsply Tulsa Dental) as the positive control. In addition, reverse-transcriptase polymerase chain reaction (RT-PCR) was used to evaluate the expression of interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α (TNF-α). Cytokine expression of MG-63 cells upon lipopolysaccharide treatment was used as controls. RT-PCR results were normalized by the expression of the housekeeping gene β-actin and were used to measure cytokine expression. Statistical analysis was performed using analysis of variance. RESULTS Results showed that ERRM putty and MTA exhibited minimal levels of cytotoxicity; however, ERRM was slightly more cytotoxic although not statistically significant. The expression of IL-1β, IL-6, and IL-8 was detected in all samples with minimal TNF-α expression. CONCLUSIONS We concluded that ERRM and MTA showed similar cytotoxicity and cytokine expressions.

Growth inhibition of Streptococcus anginosus (milleri) by three calcium hydroxide sealers and one zinc oxide-eugenol sealer.

The inhibition of growth of Streptococcus anginosus (milleri) by three calcium hydroxide sealers--calciobiotic root canal sealer (Hygienic Corporation, Akron, OH), Sealapex (Kerr Division, Sybron Corporation, Romulus, MI), and Apexit (Vivadent, USA, Amherst, NY)--was compared with a zinc oxide-eugenol sealer: Roth (Roth International, Chicago, IL). Sixteen brain heart infusion agar plates were inoculated with S. anginosus. Each plate was divided into five separate areas. In each area, a 0.1 ml droplet of a given sealer was placed such that each plate had five areas with the same sealer. There were four plates (for each of the four sealers) for a total of 20 observation areas to evaluate each sealer. The plates were incubated at 37 degrees C in a 5% CO2 atmosphere. After varying periods of incubation, the zones of inhibition of bacterial growth were observed and measured. Roth sealer had a statistically significant larger mean zone of inhibition than the calcium hydroxide sealers. However, all of the sealers exhibited clinically relevant antimicrobial activity. It is likely that the eugenol in the Roth sealer is responsible for its greater antimicrobial activity.

Effectiveness of Stannous Fluoride and Calcium Hydroxide Against Enterococcus faecalis

The objective of this study was to evaluate the antimicrobial activity of stannous fluoride, calcium hydroxide, or the two in combination against Enterococcus faecalis. Fifteen Mueller-Hinton agar plates were used to conduct a disc diffusion susceptibility test. The plates were inoculated with E. faecalis. The groups tested were: (a) stannous fluoride (Stanimax); (b) calcium hydroxide; and (c) a combination of stannous fluoride and calcium hydroxide. Three filter paper discs, each soaked with one of the groups, were placed along with an antibiotic control (ampicillin) on each agar plate. The plates were then incubated at 37 degrees C. The zones of inhibition were measured at 24 and 48 h. One-way ANOVA revealed a statistically significant difference (p < 0.05) between the three groups. Stannous fluoride displayed the widest zone (1.7 mm), followed by the combination of stannous fluoride and calcium hydroxide (1.1 mm), whereas calcium hydroxide by itself displayed a minimal zone of inhibition (0.05 mm).

Association between Systemic Diseases and Apical Periodontitis

INTRODUCTION To date, the relationships between systemic diseases and periapical microbial infection remain unknown. Thus the purpose of this systematic review was to evaluate the relationship between host modifying factors and their association with endodontic pathosis. METHODS Two reviewers independently conducted a comprehensive literature search. The MEDLINE, Embase, Cochrane, and PubMed databases were searched. In addition, the bibliographies of all relevant articles and textbooks were manually searched. There was no disagreement between the 2 reviewers. RESULTS Sixteen articles were identified and included. The overall quality of the studies and the risk of bias were rated to be moderate. Only 3 studies demonstrated a low level of bias. CONCLUSIONS The results of this review suggest that there may be a moderate risk and correlation between some systemic diseases and endodontic pathosis. More prospective and longitudinal research in this area is warranted to determine greater specificity in these possible interactions to potentially decrease or minimize the effects of systemic disease on the formation of apical periodontitis.

The effect of docosahexaenoic acid (DHA) on expression of IL-1ß, IL-6, IL-8, and TNF-α in normal and lipopolysaccharide (LPS)-stimulated macrophages.

OBJECTIVE Differentiated macrophages (MØ) are the resident tissue phagocytes and sentinel cells of the innate immune response. These cells are major constituents of periapical granulomas. Current studies indicate these activated cells as the source of bone-resorbing cytokines in the periapical granuloma. Periapical inflammation can be mediated by proinflammatory cytokines like interleukin 1ß (IL-1ß), tumor necrosis factor α (TNF-α), IL-6, and IL-8. Reducing the production of these cytokines may be beneficial for the treatment of periapical lesions. Oils rich in omega-3 fatty acids like docosahexaenoic acid (DHA) have been linked with anti-resorptive and bone-protective effects. The purpose of this investigation was to study the effect of DHA on the expression of these cytokines by normal and lipopolysaccharide (LPS)-treated MØ. We hypothesized that pretreatment of MØ with DHA decreases the expression of pro-inflammatory cytokines induced by LPS-treated MØ. METHOD AND MATERIALS THP-1 monocytes were cultured and differentiated into MØ. DHA was added to MØ in a dose-dependent manner. MØ samples were added to the following groups: Group 1, ethanol alone as a solvent control; Group 2, 10 µg/ml of DHA (D1); Group 3, 20 µg/ml of DHA (D2); Group 4, 10 µg/ml of DHA + LPS (DL1); Group 5, 20 µg/ml of DHA + LPS (DL2); Group 6, LPS alone. Reverse transcriptase-PCR (RT-PCR) followed by ImageJ analysis was used to measure cytokine expression. RESULTS The results show that IL-1ß and TNF-α levels for DL and DHA (basal) were significantly lower than the levels in LPS alone. IL-6 was increased in the DL groups. There was no significant change for IL-8. CONCLUSION DHA at higher concentrations may selectively decrease proinflammatory cytokine production of IL-1ß and TNF-α. More studies are needed to verify the anti-inflammatory therapeutic action of agents like DHA omega-3 fatty acids.

Association between Systemic Diseases and Endodontic Outcome: A Systematic Review

Introduction To date, the relationships between systemic diseases and endodontic treatment outcomes remain poorly studied. Thus, the purpose of this systematic review was to evaluate the relationship between host‐modifying factors and their association with endodontic outcomes. Methods Two reviewers independently conducted a comprehensive literature search. The MEDLINE, Embase, Cochrane, and PubMed databases were searched. In addition, the bibliographies and gray literature of all relevant articles and textbooks were manually searched. There was no disagreement between the 2 reviewers. Results Sixteen articles met the inclusion criteria with moderate to high risk of bias. There was no article with low risk of bias. Available scientific evidence remains inconclusive as to whether diabetes and/or cardiovascular disease(s) may be associated with endodontic outcomes. Human immunodeficiency virus and oral bisphosphonate did not appear to be associated with endodontic outcomes. Conclusions Although additional well‐designed longitudinal clinical studies are needed, the results of this systematic review suggest that some systemic diseases may be correlated with endodontic outcomes. HighlightsThe relationship between systemic diseases and endodontic outcome is unknown.HIV and oral bisphosphonate did not appear to be associated with endodontic outcomes.Cardiovascular disease and/or diabetes may be associated with the outcome.None of these studies can elucidate a cause‐and‐effect relationship.