Antimicrobial Effects of AH26 Sealer/Antibiotic Combinations Against Enterococcus Faecalis

INTRODUCTION: The purpose of this in vitro study was to evaluate the antimicrobial effects of two antibiotics added to AH26 sealer against Enterococcus faecalis (EF). MATERIALS AND METHODS: The antimicrobial effects of two antibiotic (amoxicillin and doxycycline) that were added separately to AH26 sealer was evaluated by using the agar diffusion test and in vitro human root inoculation method. The freshly mixed sealers were placed in prepared wells inside agar plates inoculated with EF, and were incubated at 37°C. The zones of inhibition were measured at 24, 48, 72 hours and 7 days. Root specimens were prepared and obturated with lateral condensation technique. Samples were collected from infected root canals after 2 and 7 days of incubation and the number of colony-forming units (CFU) was determined. The data were analyzed using one-way and two-way ANOVA. RESULTS: The findings of this study revealed that sealer-antibiotic combination containing amoxicillin and doxycycline had a significant difference in the mean zones of inhibition when compared to AH26 sealer alone in all of the time periods (P<0.05). The minimum effective concentration against EF was one percent of sealer powder weight for both of amoxicillin and doxycyline. The mean log10 CFU in AH26-doxycyline combination group was significantly lower than other groups at 48 h incubation period (P<0.05). AH26-doxycycline combination group and AH26-Amoxicillin combination group killed bacteria (mean CFU=0) in the dentinal tubules at 7 days incubation period. CONCLUSION: In vitro root fillings carried out with gutta-percha and AH26-antibiotic combination were effective in killing EF in dentinal tubules

Evaluation of the doxycycline release from AH26 sealer-doxycycline combination: An ex vivo study

INTRODUCTION: The purpose of this ex vivo study was to determine the releasing characteristics and doxycycline dentinal diffusion of AH26 sealer-doxycycline combination from apical 3mm of tooth root and apical foramen.MATERIALS & METHODS: One-hundred and two recently extracted single-rooted human teeth were decoronated and prepared with #3 and #4 Gates-Glidden drills and rotary Mtwo files. Smear layer was removed; all surfaces except for apical 3mm of each root were sealed with two coats of nail polish. To quantify the release and diffusion of the doxycycline at different time intervals (30 min, 48 and 72 h) after root canal obturation, the samples were randomly divided into three groups (n=30; 0.5 h, 48 h, 72 h). To evaluate the release of doxycycline from AH26 sealer-doxycycline combination at six concentrations of antibiotic including 0.5%, 1%, 2%, 5%, 10% and 20%; each experimental group was divided into six equal subgroups (n=5). Root canals were filled with gutta-percha and AH26-doxycycline combinations and then were placed in vials containing 1.25mL of phosphate buffer saline solution (PBS). After 30 min, 48 and 72 h, the amount of doxycycline released from specimens into PBS were determined by measuring the absorbance values using UV spectrophotometry at λmax=350 nm. Data were analyzed using two-way ANOVA. RESULTS: The findings of this study revealed that AH26 sealer-doxycycline combination released variable measures of antibiotic at each time interval and in the various concentrations. At 30 min, no statistically significant differences were obtained between the results of subgroups, but at 48 and 72 h these differences were significant (P < 0.001). The results also showed that differences between 0.5 h, 48 h and 72 h were significant within subgroups (P < 0.01). CONCLUSION: Under the conditions of this ex vivo study, doxycycline can be released from AH26 sealer-antibiotic combination through 3mm of apical root and apical foramen at 30 min, 48 and 72 h after mixing the sealer with doxycycline at concentrations of 0.5% up to 20%.

Subcutaneous Tissue Responses to Three Endodontic Irrigants: A Comparative Study

Introduction: This study aimed to compare the subcutaneous tissue responses to MTAD (mixture of a tetracycline isomer, an acid, and a detergent), 17% EDTA, and 2.6% NaOCl. Materials and Methods: Thirty-six Wistar albino rats were used for this study.  Test solutions were injected subcutaneously into predetermined areas on the animal dorsum. The rats were then randomly divided into three groups of twelve each and sacrificed at 2 hours, 2 days, and 2 weeks. The severity of inflammation induced by each irrigant at different time intervals was assessed histologically. The data were analyzed using Kruskal-Wallis and Friedman tests. Results: The difference in severity of inflammatory reactions induced by tested irrigants at the different time intervals was statically significant (P<0.05). There was no significant difference between the severity of inflammation induced by MTAD and 2.6% NaOCl at the various time intervals (P>0.05). Subcutaneous tissue responses to MTAD were not different from those observed in 17% EDTA specimens at 2-hour and 2-day intervals (P>0.05). Conclusion: Under the conditions of this study, MTAD has the same toxicity as 2.6% NaOCl

Effect of Blood Exposure on Push-Out Bond Strength of Four Calcium Silicate Based Cements

Introduction: The purpose of this study was to compare the push-out bond strength of white ProRoot Mineral Trioxide Aggregate (MTA), Biodentine, calcium-enriched mixture (CEM) cement and Endosequence Root Repair Material (ERRM) putty after exposure to blood. Methods and Materials: A total of 96 root dentin slices with a standardized thickness of 1.00±0.05 mm and standardized canal spaces were randomly divided into 4 main experimental groups (n=24) according to the calcium silicate based cement (CSC) used: white ProRoot MTA, CEM Cement, ERRM Putty and Biodentine. Specimens were exposed to whole fresh human blood and then subdivided into two subgroups depending on the exposure time (24 or 72 h). Push-out bond strength was measured using a universal testing machine. Failure modes were examined under a light microscope under ×10 magnification. Data were analyzed using the two-way ANOVA test. Results: Biodentine exhibited the highest values regardless of the exposure time. The lowest push-out strength values were seen in white ProRoot MTA and CEM cement in both post exposure times. After exposure to blood, the push-out bond strength of all materials increased over time. This increase was only statistically significant in white ProRoot MTA and ERRM specimens. The dominant failure mode in all CSCs was the adhesive mode. Conclusion: Biodentine showed the highest values of push-out bond strength and may be better options for situations encountering higher dislocation forces in a short time after cement application.Keywords: Biodentine; Blood; Calcium-Enriched Mixture Cement; Endosequence Root Repair Material; Mineral Trioxide Aggregat

Comparative Scanning Electron Microscopic Study of the Marginal Adaptation of Four Root-End Filling Materials in Presence and Absence of Blood

Objectives: The aim of this study was to evaluate marginal adaptation of mineral trioxide aggregate (MTA), calcium enriched mixture (CEM) cement, Biodentine and BioAggregate in presence of normal saline and human blood. Materials and Methods: In this in-vitro experimental study, 80 extracted single-rooted human teeth were instrumented and filled with gutta-percha. After resect- ing the root-end, apical cavity preparation was done and the teeth were randomly divided into 4 groups (N=20)(a total of 8 subgroups). Root-end filling materials were placed in 3mm root-end cavities prepared ultrasonically. Half the specimens in each group were exposed to normal saline and the other half to fresh whole human blood. After 4 days, epoxy resin replicas of the apical portion of samples were fabricated and scanning electron microscopy (SEM) analysis was performed to find gaps in the adaptation of the root-end filling materials at their interface with dentin. The Kruskal-Wallis and Mann-Whitney tests were used for statistical analysis of data with P<0.05 as the limit of significance. Results: There were no significant differences in marginal adaptation of the 8 tested groups (P>0.05). Conclusion: Based on the results, blood contamination does not affect the mar- ginal adaptation of MTA, CEM cement, Biodentine or BioAggregate

Effect of acidic environment on dislocation resistance of endosequence root repair material and mineral trioxide aggregate.

The aim of this study was to compare the effect of an acidic environment on dislocation resistance (push-out bond strength) of EndoSequence Root Repair Material (ERRM putty and ERRM paste), a new bioceramic-based material, to that of mineral tri-oxide aggregate (MTA).One-hundred twenty root dentin slices with standardized canal spaces were divided into 6 groups (n = 20 each) and filled with tooth-colored ProRoot MTA (groups 1 and 2), ERRM putty (groups 3 and 4), or ERRM paste (groups 5 and 6). The specimens of groups 1, 3, and 5 were exposed to phosphate buffered saline (PBS) solution (pH=7.4) and those of groups 2, 4, and 6 were exposed to butyric acid (pH= 4.4). The specimens were then incubated for 4 days at 37°C. The push-out bond strength was then measured using a universal testing machine. Failure modes after the push-out test were examined under a light microscope at ×40 magnification. The data for dislocation resistance were analyzed using the t-test and one-way analysis of variance.In PBS environment (pH=7.4), there were no significant differences among materials (P=0.30); but the mean push-out bond strength of ERRM putty was significantly higher than that of other materials in an acidic environment (

The Effect of Two Post-Space Preparation Techniques on the Seal of Resilon and Gutta-Percha Obturation Materials

INTRODUCTION: The aim of this study was to compare the effect of post space preparation with Gates Glidden drills or hand files on the sealing ability of gutta-percha or Resilon obturation materials. MATERIALS AND METHODS: One-hundred and four single-rooted human teeth were instrumented and divided into four experimental groups (n=21 each) and two groups of positive and negative control (n=10). Forty-two roots of experimental groups were obturated with gutta-percha and Dorifill sealer; and 42 roots with Resilon/Epiphany self-etch using lateral compaction technique. Each gutta-percha or Resilon group was divided into two subgroups (n=21) and post-space prepared with either Gates Glidden drills or hand files and chloroform. After post space preparation, 5 mm of apical gutta-percha or Resilon was left intact. The whole system was sterilized with gamma-rays. Saliva leakage was tested using a split-chamber model. Specimens were monitored every 24 hours for 30 days. The data were analyzed using log-rank test and Cox regression analysis. RESULTS: There were no significant differences between the sealing ability of gutta-percha and Resilon. Furthermore, no significant difference was found between two different methods of post space preparation (P>0.05). CONCLUSION: Under the limitations of this ex vivo study, there were no significant differences between the sealing ability of Resilon and gutta-percha after post space preparation using Gates Glidden drills or hand files with the aid of chloroform

The Effect of Two Post-Space Preparation Techniques on the Seal of Resilon and Gutta-Percha Obturation Materials

INTRODUCTION: The aim of this study was to compare the effect of post space preparation with Gates Glidden drills or hand files on the sealing ability of gutta-percha or Resilon obturation materials. MATERIALS AND METHODS: One-hundred and four single-rooted human teeth were instrumented and divided into four experimental groups (n=21 each) and two groups of positive and negative control (n=10). Forty-two roots of experimental groups were obturated with gutta-percha and Dorifill sealer; and 42 roots with Resilon/Epiphany self-etch using lateral compaction technique. Each gutta-percha or Resilon group was divided into two subgroups (n=21) and post-space prepared with either Gates Glidden drills or hand files and chloroform. After post space preparation, 5 mm of apical gutta-percha or Resilon was left intact. The whole system was sterilized with gamma-rays. Saliva leakage was tested using a split-chamber model. Specimens were monitored every 24 hours for 30 days. The data were analyzed using log-rank test and Cox regression analysis. RESULTS: There were no significant differences between the sealing ability of gutta-percha and Resilon. Furthermore, no significant difference was found between two different methods of post space preparation (P&gt;0.05). CONCLUSION: Under the limitations of this ex vivo study, there were no significant differences between the sealing ability of Resilon and gutta-percha after post space preparation using Gates Glidden drills or hand files with the aid of chloroform