Browsing by Subject "Root canal"

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    Antimicrobial Effects of Novel Triple Antibiotic Paste-Mimic Scaffolds on Actinomyces naeslundii Biofilm
    (Elsevier, 2015-08) Albuquerque, Maria T.P.; Ryan, Stuart J.; Münchow, Eliseu A.; Kamocka, Maria M.; Gregory, Richard L.; Valera, Marcia C.; Bottino, Marco C.; Department of Medicine, IU School of Medicine
    INTRODUCTION: Actinomyces naeslundii has been recovered from traumatized permanent teeth diagnosed with necrotic pulps. In this work, a triple antibiotic paste (TAP)-mimic scaffold is proposed as a drug-delivery strategy to eliminate A. naeslundii dentin biofilm. METHODS: Metronidazole, ciprofloxacin, and minocycline were added to a polydioxanone (PDS) polymer solution and spun into fibrous scaffolds. Fiber morphology, mechanical properties, and drug release were investigated by using scanning electron microscopy, microtensile testing, and high-performance liquid chromatography, respectively. Human dentin specimens (4 × 4 × 1 mm(3), n = 4/group) were inoculated with A. naeslundii (ATCC 43146) for 7 days for biofilm formation. The infected dentin specimens were exposed to TAP-mimic scaffolds, TAP solution (positive control), and pure PDS (drug-free scaffold). Dentin infected (7-day biofilm) specimens were used for comparison (negative control). Confocal laser scanning microscopy was done to determine bacterial viability. RESULTS: Scaffolds displayed a submicron mean fiber diameter (PDS = 689 ± 312 nm and TAP-mimic = 718 ± 125 nm). Overall, TAP-mimic scaffolds showed significantly (P ≤ .040) lower mechanical properties than PDS. Within the first 24 hours, a burst release for all drugs was seen. A sustained maintenance of metronidazole and ciprofloxacin was observed over 4 weeks, but not for minocycline. Confocal laser scanning microscopy demonstrated complete elimination of all viable bacteria exposed to the TAP solution. Meanwhile, TAP-mimic scaffolds led to a significant (P < .05) reduction in the percentage of viable bacteria compared with the negative control and PDS. CONCLUSIONS: Our findings suggest that TAP-mimic scaffolds hold significant potential in the eradication/elimination of bacterial biofilm, a critical step in regenerative endodontics.
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    Antimicrobial Efficacy of Triple Antibiotic-Eluting Polymer Nanofibers against Multispecies Biofilm
    (Elsevier, 2017-09) Albuquerque, Maria T.P.; Nagata, Juliana; Bottino, Marco C.; Biomedical Sciences and Comprehensive Care, School of Dentistry
    The elimination of microbial flora in cases of immature permanent teeth with necrotic pulp is both key and a challenging goal for the long-term success of regenerative therapy. Recent research has focused on the development of cell-friendly intracanal drug delivery systems. This in vitro study aimed to investigate the antimicrobial action of 3-dimensional (3D) tubular-shaped triple antibiotic-eluting nanofibrous constructs against a multispecies biofilm on human dentin. Polydioxanone polymer solutions, antibiotic-free or incorporated with metronidazole, ciprofloxacin, and minocycline, were electrospun into 3D tubular-shaped constructs. A multispecies biofilm consisting of Actinomyces naeslundii, Streptococcus sanguinis, and Enterococcus faecalis was forced inside the dentinal tubules via centrifugation in a dentin slice in vitro model. The infected specimens were exposed to 2 experimental groups (ie, 3D tubular-shaped triple antibiotic-eluting constructs and triple antibiotic paste [TAP]) and 2 control groups (7-day biofilm untreated and antibiotic-free 3D tubular-shaped constructs). Biofilm elimination was quantitatively analyzed with confocal laser scanning microscopy. Confocal laser scanning microscopic (CLSM) analysis showed a dense population of viable (green) bacteria adhered to dentin and penetrated into the dentinal tubules. Upon 3D tubular-shaped triple antibiotic-eluting nanofibrous construct exposure, nearly complete elimination of viable bacteria on the dentin surface and inside the dentinal tubules was shown in the CLSM images, which was similar (P < .05) to the bacterial death promoted by the TAP group but significantly greater when compared with both the antibiotic-free 3D tubular-shaped constructs and the control (saline). The proposed 3D tubular-shaped antibiotic-eluting construct showed pronounced antimicrobial effects against the multispecies biofilm tested and therefore holds significant clinical potential as a disinfection strategy before regenerative endodontics.
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    Bactericidal Efficacy of EdgePRO Er,Cr:YSGG Laser-Activated Irrigation Against a Mature Endodontic Multispecies Biofilm Using an in vitro Infected Tooth Model
    (2024) Patterson, Samuel B.; Spolnik, Kenneth J.; Gregory, Richard; Ehrlich, Ygal; Movila, Alexandru
    Introduction: Treatment goals of non-surgical root canal therapy (nsRCT) include the removal of all organic tissue material, bacterial biofilm and their by-products, and debris materials, in order to disinfect the canal system to a level compatible with healing and to further prevent infection. Standard chemo-mechanical protocols have several well-documented shortcomings and subsequent areas for improvement regarding their disinfection abilities. In recent years, emerging laser technology and its application in root canal therapy has been gaining popularity as a safe and promising tool for advancing endodontic treatment. The newest FDA-approved laser for endodontic application is the EdgePRO Erbium,Chromium-doped:Yttrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) infrared laser operating at a 2780 nm wavelength. Previous in vitro studies using Er,Cr:YSGG lasers have demonstrated their ability to enhanced canal debridement, cleaning, smear layer removal, and bacterial disinfection. Additionally, a few in vivo trails have been completed using this laser type as an adjunct in RCT procedures, which have yielded safe and highly successful results in the clinical setting. However, research specifically using the EdgePro device as well as a standardized protocol for optimal clinical usage of the laser is lacking. Objectives: The aim of this study was to evaluate the bactericidal and biofilm dissolution effects of laser-activated irrigation using the EdgePro laser against a mature multispecies biofilm in an infected tooth model and to assess the potential increased disinfection and cleaning ability compared to a standard needle irrigation protocol. Materials and Methods: Single rooted teeth (n=36) were decoronated to a standardized length of 16mm. The root canals were endodontically prepared using a standard irrigation, hand-filing, and rotary protocol to a final size of ISO 25.06 while maintaining a fully patent apical foramen. An irrigation solution reservoir was created in the coronal 4 mm of the canal space. Sterile specimens were inoculated with multispecies bacterial sample containing E. faecalis. The mixed bacteria was grown anaerobically for 10 days to form a mature biofilm using a previously established protocol. The teeth were divided into a negative control group (saline rinse, n=12), positive control group (standard needle irrigation – SNI, n=12), and an experimental group (laser-assisted treatment protocol, n=12). The positive control and experimental laser groups utilized the same irrigation solutions of 2 mL 17% EDTA followed by 5 mL 3% NaOCl using a standard 27-gauge side-vented irrigation needle placed as far apically as possible without binding. The experimental group underwent additional laser activation using laser tip #2 (350 m diameter) and settings of: 15 mJ, 0.75 W, 50 Hz, 0% air, and 0% water spray (Mid-Root Solutions 1 preset). The laser tip was inserted halfway into the irrigation filled canals (8 mm from orifice and apex) and fired upon withdrawal at a speed of 0.8 mm/sec, which comprised a single lasing cycle of 10 seconds. Three lasing cycles were completed with EDTA first followed by NaOCl, for a total of six lasing cycles with 60 seconds of irradiation time per tooth. A final rinse of sterile saline was used in all tooth samples prior to bacterial sample collection via Versa-brushes and sterile paper points. The samples were transferred to a laboratory setting where they underwent ultrasonic agitation, serial dilution, spiral plating on blood-agar, and two days of anaerobic incubation for assessment of bacterial growth. Colony forming units (CFUs/mL) were counted as a means of quantitative analysis. Results: The negative control group yielded the highest level of bacterial growth with an average of 934,771 CFUs/mL. The positive control group displayed a statistically significant lower amount of bacterial growth with an average of 4,698 CFUs/mL and yielded 1 sample with no bacterial growth. The experimental laser group had statistically significant lower bacterial growth present compared to both the positive and negative control groups and produced all negative bacterial samples with none of the 12 agar plates demonstrating CFU growth and averaged 0 CFUs/mL.. Conclusion: Within the scope of this study, laser-activated irrigation (LAI) using the EdgePro Er,Cr:YSGG laser was capable of producing no detectable bacterial samples in an in vitro infected tooth model. EdgePro LAI displayed statistically significant superior cleaning and disinfection of infected canal space compared to teeth treated with standard needle irrigation alone. The EdgePro laser system indeed shows promise as an adjunctive tool in clinical root canal treatment procedures. Further investigation is warranted using similar protocols in teeth with more complicated anatomy and with supplemental methods for analyzing bactericidal potential.
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    Dental pulp stem cell responses to novel antibiotic-containing scaffolds for regenerative endodontics
    (Wiley, 2015-12) Kamocki, K.; Nör, J. E.; Bottino, M. C.; Department of Restorative Dentistry, IU School of Dentistry
    AIM: To evaluate both the drug-release profile and the effects on human dental pulp stem cells' (hDPSC) proliferation and viability of novel bi-mix antibiotic-containing scaffolds intended for use as a drug delivery system for root canal disinfection prior to regenerative endodontics. METHODOLOGY: Polydioxanone (PDS)-based fibrous scaffolds containing both metronidazole (MET) and ciprofloxacin (CIP) at selected ratios were synthesized via electrospinning. Fibre diameter was evaluated based on scanning electron microscopy (SEM) images. Pure PDS scaffolds and a saturated CIP/MET solution (i.e. 50 mg of each antibiotic in 1 mL) (hereafter referred to as DAP) served as both negative (nontoxic) and positive (toxic) controls, respectively. High-performance liquid chromatography (HPLC) was performed to investigate the amount of drug(s) released from the scaffolds. WST-1(®) proliferation assay was used to evaluate the effect of the scaffolds on cell proliferation. LIVE/DEAD(®) assay was used to qualitatively assess cell viability. Data obtained from drug release and proliferation assays were statistically analysed at the 5% significance level. RESULTS: A burst release of CIP and MET was noted within the first 24 h, followed by a sustained maintenance of the drug(s) concentration for 14 days. A concentration-dependent trend was noticed upon hDPSCs' exposure to all CIP-containing scaffolds, where increasing the CIP concentration resulted in reduced cell proliferation (P < 0.05) and viability. In groups exposed to pure MET or pure PDS scaffolds, no changes in proliferation were observed. CONCLUSIONS: Synthesized antibiotic-containing scaffolds had significantly lower effects on hDPSCs proliferation when compared to the saturated CIP/MET solution (DAP).
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    An in-vitro comparison of bacterial microleakage of gutta-percha and the Guttacore cross-linked gutta-percha core obturator
    (2013) Edds, Abigail C.; Spolnik, Kenneth Jacob, 1950-; Gregory, Richard L.; Vail, Mychel Macapagal, 1969-; Legan, Joseph J.; Zunt, Susan L., 1951-; Ehrlich, Ygal
    Root canal therapy requires three important steps accomplished in concert to achieve long-term success: canal shaping, disinfection, and obturation. Traditionally gutta-percha has been used with sealer in a cold lateral condensation technique. Schilder introduced the concept of warm vertical compaction of gutta-percha in 1967 to attempt to obturate more canal irregularities. Johnson presented the use of stainless steel files with thermally plasticized gutta-percha in 1978, and later the metal carrier was changed to plastic and named Thermafil. Thermafil has shortcomings in that it does not always fulfill Grossman’s obturation material properties, such as apical extent of the material (extrusion) and ease of retreatment. A new obturation material by Dentsply Tulsa, the GuttaCore cross-linked gutta-percha core obturator, has been introduced that replaces the plastic core with a cross-linked gutta-percha core. The manufacturer states removal of the obturation material and 89 core is fast and easy. To date, no microleakage studies have been done to test this newer obturation material. Methods used to study microleakage have included the use of dyes, radioisotopes, electrochemicals, fluid filtration, and microorganisms. A microbial leakage model has been constructed using a modified two-chamber apparatus as described by Torabinejad et al. and has been used successfully. Green fluorescent protein (GFP) from the jellyfish Aequorea victoria is useful as a bacterial label because the fluorescent marker can be exhibited in the bacterial host without having to use stains. A plasmid that encodes for a copy of the green fluorescent variant gene was transferred into the E. faecalis. The marker glows green under a standard fluorescence microscope and has been used successfully to evaluate microleakage. The purpose of this investigation was to evaluate the sealing ability of a new obturation material, GuttaCore, to determine if there will be a significant decrease in microleakage of AH Plus with GuttaCore obturator versus AH Plus with gutta-percha. Sixty-two human, single-rooted premolars extracted for periodontal considerations were accessed and instrumented for non-surgical root canal therapy. Hand and rotary instrumentation was accomplished to MAF size 40.04, and irrigation was accomplished with 6.0-percent NaOCl and 17-percent EDTA with use of EndoActivator. Teeth were randomly assigned to two experimental groups of 27 teeth each. Group I (conventional method) teeth were obturated with gutta-percha and AH Plus sealer using warm vertical condensation, and Group II (test method) teeth were obturated with GuttaCore and AH Plus sealer. Two control groups containing four teeth each 90 served as positive and negative controls. The positive and negative control groups ensured that the microleakage model was working correctly. The teeth were evaluated for microbial microleakage of E. faecalis green fluorescent protein (GFP) construct using a dual chamber leakage model. If turbidity is observed in the lower chamber, it will indicate microleakage and an inadequate seal of the obturation method. The teeth were sectioned and viewed with a standard fluorescence microscope to determine the depth of microleakage utilizing the inherent fluorescence of the E. faecalis GFP construct. No microleakage was observed in the negative control groups. Microleakage was observed in both gutta-percha positive control groups and in one of the two GuttaCore positive control groups. One of 27 GuttaCore samples displayed turbidity, which occurred at day 14. None of the 26 gutta-percha samples displayed turbidity at any point. The 95-percent confidence intervals (CI) for the percentage of samples with turbidity were 0.1 percent to 19 percent for GuttaCore and 0.0 percent to 13.2 percent for gutta-percha using a Fisher’s Exact Test. The two groups did not have a significantly different percentage of samples with turbidity (p =1.00). No E. faecalis GFP was visualized under fluorescent microscopy in either the turbid GuttaCore sample or the gutta-percha positive control in the apical, middle or coronal thirds. Both samples that demonstrated microleakage had confirmation that the lower chamber broth contained E. faecalis GFP when cultured on blood agar plates. Within the limitations of this study, there was no significant decrease in microleakage between the GuttaCore obturator and warm vertical condensation with gutta-percha. Turbidity of the broth in samples that leaked was not associated with 91 noticeable bacteria when using fluorescent microscopy, which indicated that leakage may be the result of very few bacteria.