Coronal tooth discoloration induced by regenerative endodontic treatment using different scaffolds and intracanal coronal barriers: a 6-month ex vivo study

OBJECTIVE: The aim of this study was to evaluate discoloration of teeth undergoing regenerative endodontic procedures (REPs) using blood clot or platelet-rich fibrin (PRF) as the scaffolds and different calcium silicate-based materials as the intracanal coronal barriers in an ex vivo model. MATERIALS AND METHODS: Forty-eight bovine incisors were prepared and disinfected using 1 mg/mL double antibiotic paste (DAP). The specimens were then randomly divided into 2 groups (n = 24) according to the scaffolds (blood or PRF). After placement of scaffolds each group was divided into 2 subgroups (n = 12) according to the intracanal coronal barriers (ProRoot MTA or Biodentine). The pulp chamber walls were sealed with dentin bonding agent before placement of DAP and before placement of scaffolds. The color changes (∆E) were measured at different steps. The data were analyzed using 2-way analysis of variance. RESULTS: Coronal discoloration induced by DAP was not clinically perceptible (ΔE ≤ 3.3). Regarding the type of the scaffold, coronal discoloration was significantly higher in blood groups compared with PRF groups at the end of REP and after 1 month (p 0.05). Considering the type of intracanal coronal barrier, no significant difference existed between ProRoot MTA and Biodentine (p > 0.05). CONCLUSIONS: With sealing the dentinal tubules of pulp chamber with a dentin bonding agent and application of DAP as an intracanal medicament, coronal color change of the teeth following the use of PRF and blood sealed with either ProRoot MTA or Biodentine was not different at 6-month follow-up.

Surface microhardness of three thicknesses of mineral trioxide aggregate in different setting conditions

OBJECTIVES: This study aimed to compare the surface microhardness of mineral trioxide aggregate (MTA) samples having different thicknesses and exposed to human blood from one side and with or without a moist cotton pellet on the other side. MATERIALS AND METHODS: Ninety cylindrical molds with three heights of 2, 4, and 6 mm were fabricated. In group 1 (dry condition), molds with heights of 2, 4, and 6 mm (10 molds of each) were filled with ProRoot MTA (Dentsply Tulsa Dental), and the upper surface of the material was not exposed to any additional moisture. In groups 2 and 3, a distilled water- or phosphate-buffered saline (PBS)-moistened cotton pellet was placed on the upper side of MTA, respectively. The lower side of the molds in all the groups was in contact with human blood-wetted foams. After 4 day, the Vickers microhardness of the upper surface of MTA was measured. RESULTS: In the dry condition, the 4 and 6 mm-thick MTA samples showed significantly lower microhardness than the 2 mm-thick samples (p = 0.003 and p = 0.001, respectively). However, when a distilled water- or PBS-moistened cotton pellet was placed over the MTA, no significant difference was found between the surface microhardness of samples having the abovementioned three thicknesses of the material (p = 0.210 and p = 0.112, respectively). CONCLUSIONS: It could be concluded that a moist cotton pellet must be placed over the 4 to 6 mm-thick MTA for better hydration of the material. However, this might not be necessary when 2 mm-thick MTA is used.

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

Coronal microleakage in root canals obturated with lateral compaction, warm vertical compaction and GuttaFlow system

Root canal obturation seals the root canal system to prevent re-entry and/or growth of microorganisms. The provision of an appropriate restoration to coronally seal the access cavity affects the success of endodontic treatment. The purpose of this study was to evaluate the coronal microbial leakage in root canals that were either filled by lateral compaction, GuttaFlow or warm vertical compaction. In this ex vivo study, 80 single-rooted human extracted teeth were randomly divided into three experimental groups [n=20] and two positive and negative control groups [n=10]. The teeth in experimental groups were obturated with cold lateral compaction, GuttaFlow system or warm vertical compaction techniques. After sterilization of the whole system with gamma-ray, 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 and Kaplan-Meier survival analysis tests. There were no significant differences in impeding saliva leakage between the three experimental groups [P>0.05]. Under the conditions of this ex vivo study, it can be concluded that the sealing ability of cold lateral compaction, warm vertical compaction and GuttaFlow system was comparable

Mandibular first and second molars with three mesial canals: a case series

Adequate cleaning, shaping and filling of the root canal system are mandatory for successful root canal treatment. Thorough knowledge of root canal morphology and unusual anatomy of the tooth is critical for the practitioner. The occurrence and location of the third mesial canal [Middle Mesial Canal] in mandibular first and second molars in relation to other two mesial canals that were treated in private practice were studied. In 27 clinical cases, the presence of a middle mesial canal was demonstrated. The third canal was located in the middle of the distance between the mesiobuccal and mesiolingual canals. This canal configuration was found in six second lower molars and twenty one first molars. Middle mesial canal in all of our cases joined to mesiobuccal or mesiolingual canals. None of the teeth consisted of three independent canals with three apical foramina. In conclusion, every attempt should be made to find and treat all root Canals of a tooth

Efficacy of three different methods in the retreatment of root canals filled with Resilon/Epiphany SE

The purpose of this study was to evaluate the efficacy of three methods in removal of Resilon/new Epiphany self-etch [SE] soft resin endodontic obturation system. Thirty extracted single rooted human teeth were prepared for endodontic treatment and obturated with Resilon/Epiphany SE. The roots were randomly divided into three groups; group 1 roots were retreated using Mtwo R/Mtwo files; group 2 were retreated using Mtwo R/Mtwo accompanied with chloroform; and group 3 were retreated using Mtwo R/Mtwo accompanied with Endosolv R. The cleanliness of canal walls was determined using scanning electron microscopy. Data were analyzed using ANOVA and LSD tests. Endosolv R combined with rotary files was more efficient in material removal compared to chloroform combined with rotary files and rotary files alone [P<0.05]. Also, chloroform combined with rotary file was more efficient than rotary file alone in removing filling material from the root canals. Significant difference was found within group 1 between the coronal third compared to the middle and apical thirds [P<0.05]. In group 2, there were more material remnants in the apical third [P<0.05]. In group 3, there was no significant difference between the three segments of the root canals [P>0.05]. All techniques left filling material remnants and debris on the root canal walls. Endosolv R combined with rotary files most effectively removed filling materials from the root canals, especially in the apical third

Retreatment of a 6-canalled mandibular first molar with four mesial canals: a case report

Successful root canal treatment requires adequate knowledge regarding morphologic variations in root canal system of teeth. This report describes a six-canalled mandibular first molar with four mesial root canals requiring endodontic retreatment. The two additional canals in the mesial root were found during retreatment with the aid of illumination and magnification. In conclusion, the possibility of atypical morphology and additional canals should never be overlooked

In vitro comparison of the effectiveness of Chiorhexidine and two calcium hydroxide formulations on Enterococcus faecalis

The aim of this in vitro study was to compare the effectiveness of three intracanal medicaments in disinfecting the root canal and dentin of experimentally infected human teeth with Enterococcus faecalis [EF]. One hundred extracted human single-rooted teeth were used. After root canal preparation, teeth were mounted in epoxy resin. Following sterilization, the teeth were infected for 28 days with EF. Then root canals were filled with one of three different disinfectants: viscous 2% Chlorhexidine [CHX], calcium hydroxide paste [CH] or a mixture of CH and CHX [n=30 in each group]. Antimicrobial assessments were performed at 1, 3 and 7 days [n=10 in each time period]. Microbial samples were obtained from root canals before and after the experiment. Also dentin samples were examined. The data was analyzed using Two- Way ANOVA test. The findings showed that there was no difference between experimental groups at different time periods. The mixture of CH/CHX in 7 days was able to eliminate EF completely from root canal system. The most elimination of EF was from dentinal tubules. According to the results of this in vitro study, viscous 2% CHX, mixture of CH with distilled water and 2% CHX are all effective disinfectants