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Browsing by Author "Yassen, Ghaeth"
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Item 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, JosefThe 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.Item 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, GhaethWe 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.Item The antibacterial effects of radiopaque double antibiotic pastes against clinical bacterial isolates from mature and immature teeth with necrotic pulps(2018) Ibrahim, Carolin Francis; Spolnik, Kenneth J.; Ehrlich, Ygal; Gregory, Richard L.; Zunt, Susan; Bringas, Josef; Yassen, GhaethLow concentrations (1-10mg/mL) of double antibiotic paste (DAP) have demonstrated antibacterial properties in regenerative endodontics. The aim of this study was to evaluate if DAP made radiopaque (RoDAP) with barium sulfate has antibacterial effects against bacterial isolates from a mature and immature tooth with necrotic pulp. Clinical bacterial isolates were obtained from the canals of mature and immature teeth with necrotic pulps during root canal therapy or a regenerative procedure, respectively. Bacterial isolates were grown anaerobically for three weeks on 4x4mm dentin specimens prepared from extracted human teeth (n=48 per biofilm type). The dentin specimens were allocated into six groups and treated as follows: 1mg/mL RoDAP, 10mg/mL RoDAP, calcium hydroxide (UltraCal), placebo (barium sulfate in methylcellulose), no treatment, and no bacteria or treatment (sterile control). After one week of treatment the biofilm was detached and biofilm disruption assays were conducted to determine the bacterial numbers (CFUs/mL). The data was analyzed using Wilcoxon Rank Sum tests followed by pairwise comparisons. 1 and 10 mg/mL RoDAP as well as calcium hydroxide demonstrated significant antibacterial effects against the tested bacterial isolates. The placebo paste did not demonstrate any significant antibacterial effects. No significant difference in antibacterial effects was found against isolates from both mature and immature teeth regardless of the type of treatment. Both 1 and 10 mg/mL RoDAP demonstrated significant antibacterial effects against bacterial isolates from mature and immature teeth with necrotic pulps. RoDAP can be beneficial clinically since its adequate placement within the canal system can be confirmed radiographically.Item The antibacterial stability of a new radiopaque double antibiotic paste(2018-06) Epkey, Kathryn Eileen; Spolnik, Kenneth J.; Ehrlich, Ygal; Gregory, Richard L.; Zunt, Susan; Bringas, Josef; Yassen, GhaethWe evaluated the antibacterial stability (shelf life) of a new radiopaque double antibiotic paste (RoDAP) loaded in a methylcellulose system with 30% w/v barium sulfate against biofilm collected from an immature tooth with necrotic pulp. Uniform radicular dentin specimens were infected with bacterial biofilm obtained from an immature tooth with a necrotic pulp and incubated anaerobically for three weeks. These samples were randomly divided into 6 experimental groups (n=7) and treated for 1 week at three time points of aged radiopaque DAP: 0 months, 3 months, and 6 months. Group 1: 1mg/mL RoDAP treatment. Group 2: 10 mg/mL RoDAP treatment. Group 3: Calcium hydroxide (Ca(OH)2) treatment. Group 4: Methylcellulose with barium sulfate. Group 5: No treatment. Group 6: No bacteria or treatment. The samples were rinsed with sterile saline to detach biofilms and then spiral plated using a biofilm disruption assay. Statistical analyses were performed using Wilcoxon rank-sum tests and Wilcoxon signed rank tests with fixed effects for treatment, time, and the treatment-by-time interaction. Treatment of infected dentin with 1 mg/mL RoDAP, 10 mg/mL RoDAP, and Ca(OH)2 demonstrated significant and substantial antibiofilm effects in comparison to untreated control groups or groups treated with placebo paste after 0, 3, and 6 months of aging. Calcium hydroxide, however, showed slightly less antibiofilm activity after 6 months of aging when compared to 0 months and 3 months of aging. This difference was statistically significant (p > 0.05). In conclusion, both concentrations of RoDAP maintained full antibacterial efficacy after 6 months of aging, while calcium hydroxide lost some antibacterial activity after a shelf life of 6 months.Item Effect of low concentrations of antibiotic intracanal medicaments on crown discoloration and push-out bond strength(2018-07-12) Yaghmoor, Rayan Bahjat M.; Platt, Jeffrey A; Yassen, Ghaeth; Spolnik, Kenneth J.; Chu, Tien Min GabrielIntroduction: Some intracanal medicaments used in regenerative endodontics may compromise the bond strength of root cements and lead to tooth discoloration. Objectives: To evaluate the effects of 1) low concentrations of TAP and DAP (1 mg/mL) on push-out bond strength of various root cements, and 2) low concentrations of TAP and DAP (1 mg/mL and 10 mg/mL) on crown discoloration. Materials and Methods: Single rooted human teeth (n = 144) were horizontally decoronated and instrumented according to standardized protocol. The samples were randomized into six experimental groups (Ca(OH)2, 1000 mg/mL TAP and DAP, 1 mg/mL TAP and DAP, and no medicament control group. After four weeks, the medicaments were removed and each group was divided into three subgroups to receive MTA cement, Biodentine cement, or Endosequence Bioceramic putty cement for two weeks. Then, two root cylinders were obtained from each root and push-out bond strength testing was performed. For the crown discoloration experiment, 160 crowns were obtained from intact human molars and randomized into experimental groups as described earlier with the addition of two groups (10 mg/mL TAP and DAP). The pulp chambers in half of the samples from each group were coated with an adhesive bonding agent before receiving the assigned intracanal medicament. Color changes (ΔE) were detected by spectrophotometer at 1 day, 1 week, and 4 weeks after application, as well as after thermocycling. Results: In the push-out bond strength experiment, 1 mg/mL DAP generally demonstrated significantly higher bond strength of root cements compared with the other treatment groups. For the crown discoloration experiment, when an adhesive bonding agent was used prior to (10 mg/mL or 1000 mg/mL) TAP, the crowns had significantly less discoloration than those without adhesive. DAP 10 mg/mL had the least significant color change at all time points regardless of whether adhesive was used. Conclusion: 1) 1 mg/mL DAP and Ca(OH)2 did not have significant negative effect on the bond strength of calcium-silicate-based cement to radicular dentin. 2) 1 mg/mL and 10 mg/mL of DAP and Ca(OH)2 had significantly less effect on the color change of the human tooth crown than all intracanal medicaments used in this study.