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

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. One-hundred and two recently extracted single-rooted human teeth were decoronated and prepared with [number sign] 3 and [number sign] 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 lambda max=350 nm. Data were analyzed using two-way ANOVA. 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]. 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%

effect of two post-space preparation techniques on the seal of Resilon and gutta-percha obturation materials

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. 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. 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]. 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

Antimicrobial effects of AH26 sealer/antibiotic combinations against Enterococcus faecalis

The purpose of this in vitro study was to evaluate the antimicrobial effects of two antibiotics added to AH26 sealer against Enterococcus faecalis [EF]. The antimicrobial effects of two antibiotic [amoxicillin and doxycycline] that were added separately to AH[26] 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. 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 AH[26] 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 log[10] CFU in AH[26]-doxycyline combination group was significantly lower than other groups at 48 h incubation period [P<0.05]. AH[26]-doxycycline combination group and AH26-Amoxicillin combination group killed bacteria [mean CFU=0] in the dentinal tubules at 7 days incubation period. In vitro root fillings carried out with gutta-percha and AH26-antibiotic combination were effective in killing EF in dentinal tubules