Browsing by Subject "DAP"

Now showing 1 - 4 of 4
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    The ability of new intracanal medicaments to prevent the formation of multi-species biofilm on radicular dentin
    (2017) Jacobs, Jordon C.; Spolnik, Kenneth J.; Ehrlich, Ygal; Gregory, Richard L.; Yassen, Ghaeth; Bringas, Josef
    The residual antibacterial effects of antimicrobials used in endodontic regeneration against biofilm bacteria obtained from immature and mature teeth Jordon C. Jacobs DDS, Richard L Gregory PhD, Ygal Ehrlich DMD, Kenneth Spolnik DDS, MS, Josef S. Bringas DMD, DDS, MS, and Ghaeth Yassen BDS, MSD, PhD We explored the residual antibacterial properties of dentin pretreated with low concentrations of double antibiotic paste (DAP) against biofilm bacteria obtained from different clinical sources. Dentin blocks were sterilized and randomized into 4 treatment groups and 2 control groups (n=20). Blocks from treatment groups were pretreated with DAP (1 or 5 mg/ml) loaded into methylcellulose, calcium hydroxide (Ca(OH)2), or methylcellulose paste. After one week, the treatment pastes were removed and all blocks were immersed in PBS. The dentin blocks from treatment groups and one of the control groups were then inoculated with bacterial isolates obtained from immature or mature teeth with pulpal necrosis(n=10). The remaining control group received no bacteria and was used as a sterile control. Blocks were then incubated anaerobically for 3 weeks. Biofilm disruption assays were conducted for all samples. Two-way ANOVA and pair-wise comparisons were used for statistical analyses. The residual antibacterial effect of dentin pretreated with 5 mg/ml of DAP was significantly higher than all other groups regardless of the source of biofilm. Dentin pretreated with 1 mg/ml of DAP demonstrated significantly higher residual antibacterial effects in comparison to dentin pretreated with placebo paste and Ca(OH)2 only in bacterial isolates obtained from mature teeth with pulpal necrosis. Dentin pretreated with Ca(OH)2 did not demonstrate any residual antibacterial effects. Dentin pretreated with 1 or 5 mg/ml of DAP demonstrated significantly better residual antibacterial effects against biofilm bacteria obtained from mature teeth with pulpal necrosis in comparison to bacterial isolates obtained from immature teeth with pulpal necrosis.
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    The antibacterial effect of new intracanal medicaments against established mutlispecies biofilm
    (2017) Troxel, Alex; Spolnik, Kenneth J.; Gregory, Richard; Ehrlich, Ygal; Bringas, Josef; Zunt, Susan L.; Yassen, Ghaeth
    We investigated the antibacterial effect of low concentrations of double antibiotic paste (DAP) loaded into a methylcellulose system against bacterial biofilms obtained from mature and immature teeth with necrotic pulps. Standardized radicular dentin specimens were randomly divided into six experimental groups (n = 20). Group 1: 5mg/mL DAP treatment. Group 2: 1mg/mL DAP treatment. Group 3: Calcium hydroxide (Ca(OH)2) treatment. Group 4: Methylcellulose. Group 5: No treatment. Group 6: No bacteria or treatment. Clinical bacterial isolates were obtained from mature and immature teeth with necrotic pulps indicated for endodontic regeneration or routine endodontic treatment, respectively. Specimens in each group were inoculated with either bacterial isolates (n = 10) and incubated anaerobically for 3 weeks. Specimens were then treated for one week with the assigned group treatment. Treatments were rinsed with sterile saline and biofilms were detached and spiral plated using biofilm disruption assays. Wilcoxon Rank Sum tests followed by pair-wise comparisons were used for statistical analyses. Treatment of infected dentin with 1 mg/ml of DAP, 5 mg/mL of DAP, and Ca(OH)2 demonstrated significant and substantial antibiofilm effects in comparison to untreated control groups or groups treated with placebo paste. Furthermore, 1 mg/mL of DAP caused complete eradication of biofilm obtained from mature tooth with necrotic pulp. However, the same concentration was not able to completely eradicate biofilm obtained from the immature tooth with necrotic pulp. Low concentrations of DAP (1-5 mg/mL) loaded into a biocompatible methylcellulose system demonstrated significant antibacterial effects against biofilm obtained from both mature and immature teeth with necrotic pulps.
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    The effects of concentration and treatment time on the residual antibacterial properties of DAP
    (2016) Jenks, Daniel Brent; Spolnik, Kenneth J.; Bringas, Josef; Gregory, Richard L.; Yassen, Ghaeth H.; Ehrlich, Ygal; Warner, Ned A.
    Introduction: Regenerative endodontic procedures are used to treat immature teeth with pulpal necrosis in order to control infection, enable continued root development and enhance formation of a pulp like tissue in the canal. Canal disinfection is an integral part the regenerative endodontic process. Double antibiotic paste (DAP; i.e., equal parts of ciprofloxacin and metronidazole) has been successfully used for canal disinfection in regenerative endodontics. A comparison of the residual antibacterial effect of dentin treated with various dilutions of DAP pastes on biofilm formation has not yet been investigated thoroughly. Objectives: The aims of this in-vitro study were to investigate how concentration and time of treatment affect the residual antibacterial properties of DAP in preventing E. faecalis biofilm formation on human dentin. Materials and Methods: Extracted human teeth were used to obtain 4x4mm radicular dentin specimens. Each specimen was pretreated for 1 or 4 weeks with the 77 clinically used concentration of DAP (500 mg/mL), low concentrations of DAP (1, 5 or 50 mg/mL) loaded into a methylcellulose system, calcium hydroxide (Ca(OH)2), or placebo paste. After treatment, samples were rinsed and placed in sterile phosphate buffered saline (PBS) for three weeks. Samples were then inoculated with cultured E. faecalis and incubated in anaerobic conditions for three weeks to allow mature biofilm formation. The dentin samples were rinsed and biofilms detached. The detached biofilm cells were then diluted and spirally plated for enumeration on blood agar plates. The plates were then incubated for 24 h and the number of CFUs/mL was determined using an automated colony counter. Data was analyzed using Fisher’s Exact and Wilcoxon rank sum tests were used for statistical comparisons (α=0.05). Results: Dentin pretreatment for 4 weeks with 5, 50 or 500 mg/mL of DAP demonstrated significantly higher residual antibacterial effects and complete eradication of E. faecalis biofilms in comparison to a 1 week pretreatment with similar concentrations. However, dentin pretreated with 1 mg/mL of DAP or Ca(OH)2 did not provide a substantial residual antibacterial effect regardless of the application time. Conclusion: Dentin treated with 500, 50, or 5 mg/mL of DAP for 4 weeks was able to completely prevent the colonization of bacterial biofilm. Four-week treatment of dentin with DAP offers superior residual antibacterial effect in comparison to a one-week treatment. Intracanal application of DAP for 4 weeks during endodontic regeneration may offer an extended residual antibacterial effect.
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    The Effects of Nano-Hydroxyapatite in a Double Antibiotic Paste-Loaded Methycellulose Carrier on Dental Pulp Stem Cells
    (2019) Everhart, Adam R.; Spolnik, Kenneth J.; Bruzzaniti, Angela; Bringas, Josef S.; Ehrlich, Ygal; Gregory, Richard L.
    The effects of hydroxyapatite in a DAP-loaded MC carrier on dental pulp stem cells Introduction: Regenerative endodontic procedures (REP) require disinfection techniques to eliminate bacteria from the infected immature root canal system and promote new growth of the pulp-dentin complex. Double antibiotic paste (DAP), a mixture of ciprofloxacin and metronidazole, has shown efficacy in doing so while minimizing cytotoxicity on dental pulp stem cells (DPSC). Stem cells, scaffolding, and growth factors are necessary in the maturation, proliferation, and differentiation of mesenchymal stem cells into the root canal system. Nano-hydroxyapatite (n-HA) has a history of biocompatibility and, in addition, has shown promising effects as a tissue bioengineering material. Objective: The aim of this in vitro study was to investigate the proliferation and mineralization of DPSC in the presence of 1% DAP and methylcellulose (MC) with varying concentrations of nano-hydroxyapatite. Materials and Methods: DPSC were plated in 24-well plates containing culture media. The next day, semi-permeable 0.1 mm Transwell chambers were inserted into the wells to separate the reservoirs for medicaments. Treatment paste composed of methylcellulose containing 1% DAP with either 0.25%, 0.50%, or 1.0% nano-hydroxyapatite was added along with culture media. Methylcellulose alone and calcium hydroxide (Ultracal) were used as control groups. After 3 days, cells were evaluated for cytotoxic effects using an MTS proliferation assay (n = 10, in triplicate). DPSCs were also cultured with these medicaments for 7 days in osteogenic media and evaluated for alkaline phosphatase (ALP) activity and mineralization activity (n = 13, in triplicate). Comparisons between groups for differences in mineralization, BSA, and ALP activity were performed using analysis of variance (ANOVA), with different variances allowed for each group and a random effect included in the model to account for correlation within each of the three trials. A simulation-based model was used to adjust for multiple comparisons. Results: Addition of n-HA treatment groups increased mineralization significantly greater than calcium hydroxide, with MC alone and MC+DAP+0.5% HA providing the greatest effect. Regarding ALP, all HA concentrations performed significantly greater than MC and DAP concentrations. Proliferation demonstrated similar metabolic activity in all experimental groups with few comparisons significant. Conclusion: The challenge in REPs is to maintain survival, and preferably promote the proliferation and development of DPSCs into the pulp-dentin complex with a consistent treatment outcome. The combination of DAP with hydroxyapatite may allow for both disinfection and improved mineralization and cellular differentiation. This contribution has shown significant ability to increase stem cell differentiation into an osteogenic lineage as well as calcium deposition, indicating end goal results of regenerative procedures.