The effect of two rotary and two reciprocating NiTi systems on postoperative pain after root canal retreatment on single-rooted incisor teeth: A randomized controlled trial.

AIM: This randomized clinical trial aimed to assess the effect of two rotary (ProTaper Retreatment + ProTaper Gold and Hyflex EDM) and two reciprocating (Reciproc Blue and WaveOne Gold) NiTi systems on postoperative pain after root canal retreatment on single-rooted incisor teeth. METHODOLOGY: One hundred and eighty patients scheduled for root canal retreatment were randomly assigned to one of the four groups according to the NiTi system (ProTaper Retreatment + ProTaper Gold, Hyflex EDM, Reciproc Blue or WaveOne Gold) used for the removal of root canal fillings and further canal preparation. The working length was determined to be 1 mm shorter than the '0.0' mark of the apex locator. Root canals were filled with gutta-percha and an epoxy resin-based root canal sealer using a lateral compaction technique. The teeth were restored using a resin composite material. A single operator performed the retreatments in a single visit. The incidence and intensity of postoperative pain were rated on a numeric rating scale by patients 24, 48 and 72 h after retreatment. The number of analgesic tablets (400 mg Ibuprofen) taken by patients was also recorded. Data were analysed using the Mann-Whitney U, Wilcoxon and chi-square tests. RESULTS: For the intensity of postoperative pain, the difference between the four groups was not significantly different (p > .05). No significant difference was found between the groups in terms of analgesic medication intake (p > .05). CONCLUSIONS: The rotary and reciprocating NiTi systems tested in this study were associated with similar intensity of postoperative pain and intake of analgesics following root canal retreatment on single-rooted incisor teeth completed in one visit.

Evaluation of Time-Dependent Temperature Changes during Different Interdental Stripping Procedures by Thermal Imaging: An In Vitro Study.

PURPOSE: To investigate the temperature changes in pulp chamber of incisor and canine teeth during different stripping procedures with thermal imaging. MATERIALS AND METHODS: Intact and freshly extracted human permanent 40 maxillary lateral incisor, 40 mandibular canine and 40 mandibular incisor teeth were selected for this study. Diamond bur, tungsten carbide bur and perforated diamond-coated disc were used for interdental stripping in high and low speed handpieces by air and water cooling. Temperature changes and cooling time of the tooth groups were recorded by a thermal imaging system. Paired t test and one-way analysis of variance (ANOVA) tests were performed for intragroup and intergroup comparisons of temperature changes and cooling time values. RESULTS: Stripping procedures created a statistically significant temperature rise in all study groups (p < 0.05). For maxillary lateral incisors and mandibular incisors, the greatest temperature rise was calculated during stripping with tungsten bur and perforated disk under air cooling (p < 0.001), while no statistically significant difference was found between the temperature rise values of mandibular canine teeth during different stripping procedures (p = 0.053). The lowest temperature rise and cooling time values among all tooth groups were observed during stripping with diamond bur under water cooling and the longest cooling time values were detected during stripping with perforated disc under air cooling (maxillary incisor; p < 0.001, mandibular incisor; p < 0.05, mandibular canine; p < 0.05). CONCLUSION: For all tooth groups, stripping with diamond bur in a high speed handpiece under water cooling produced the lowest temperature rise in the pulp chamber and the shortest cooling time values among different stripping procedures.

Effects of High-Energy Curing Lights on Time-Dependent Temperature Changes of Pulp Space During Orthodontic Bonding.

OBJECTIVE: The purpose of this study was to assess the temperature changes and cooling times during orthodontic bonding by a light-emitting diode (LED) and plasma arc lights (PAC) in different time and power modes with thermal imaging. METHODS: A total of 100 human permanent upper first premolar teeth were included in the study. Five groups were conducted, 20 teeth each, and different energy outputs of curing lights were used for adhesive polymerization with different exposure times. The temperature changes in the pulp space and cooldown times were measured by a thermal imaging system. A paired t-test, analysis of variance (ANOVA), and Student-Newman-Keuls multiple comparison tests were used for data analysis. RESULTS: A statistically significant temperature rise was detected with all curing lights (p<0.05). The greatest temperature changes were observed in the LED standard mode with 10 seconds of exposure time (6.66±1.98°C) and LED extra power mode with 6 seconds of exposure time (6.50±1.64°C) among groups, while using PAC for 3 seconds created the smallest temperature increase (1.81±0.99°C). An application of the LED extra power mode for 6 seconds exhibited the longest cooldown time (205.91±47.48 seconds), and the shortest cooldown time was detected as 71.30±43.15 seconds with the PAC 3-second application. CONCLUSIONS: LED lights with an increased exposure time induced significant temperature rises, while no PAC light group exceeded the critical threshold value. The exposure time is more important than the energy output level of the light-curing system on temperature increments of the pulp chamber.

Thermal imaging of the pulp during residual adhesive removal.

OBJECTIVE: The aim of this study was to evaluate the temperature changes of the pulpal area during different adhesive clean-up procedures. MATERIALS AND METHODS: A total of 80 freshly extracted adult maxillary premolar teeth were divided into four groups. Adhesive clean-up was performed with 6- and 12-fluted tungsten carbide burs (TCB) using low- and high-speed handpieces with air or water cooling after bracket debonding. The temperature changes and cool down times were evaluated with a thermal camera. Paired t test, analysis of variance (ANOVA), and Student-Newman-Keuls multiple comparison analysis were used for statistical analysis of the data. RESULTS: All experimental groups, except the water cooling group, showed a significant temperature rise (p < 0.001) after residual adhesive removal. Only the 6-fluted TCB group with air cooling using a high-speed handpiece exceeded the critical 5.5 °C threshold value (5.91 ± 0.89 °C); this group also exhibited the longest cool down time to initial temperature (71.95 ± 13.68 s). The smallest temperature rise (0.48 ± 0.90 °C) and shortest cooling time value (11.90 ± 5.3 s) were measured in the 6-fluted TCB group with water cooling using a high-speed handpiece. CONCLUSION: Appropriate cooling procedures and fine tungsten carbide burs should be used during the removal of remnant adhesives after bracket debonding in order to prevent adverse pulpal reactions.

Fracture resistance of teeth with oval canal morphology restored using oval and circular posts.

The study aimed to evaluate the effects of different post morphologies and placement lengths on the fracture resistance of teeth with oval canal morphology that had been restored with crowns. Extracted mandibular premolars with similar dimensions were decoronated. After the root canal treatment, the teeth were mounted on acrylic blocks. Samples were randomly divided into four groups (n = 10 each). In groups C-10 and C-5, 10-mm- and 5-mm-long circular post spaces were created. In groups O-10 and O-5, 10-mm- and 5-mm-long oval post spaces were ultrasonically created. After post cementation, all specimens were restored with composite cores and prepared at height of 6 mm. Thereafter, all teeth were restored with crowns. After thermocycling, all specimens underwent fracture resistance testing. Oval posts and placement at 10-mm depth showed higher fracture resistance than circular posts and placement at 5-mm depth (P < 0.001). Increased post length and use of oval posts enhanced the fracture strength of teeth with oval canal morphology. Based on the results of this study, although the fracture resistance of teeth restored with crowns was enhanced by deep fiber post placement, the use of oval fiber post is recommended in cases where deep placement is impossible. (J Oral Sci 58, 339-345, 2016).

Evaluation of Apically Extruded Debris from Curved Root Canal Filling Removal Using 5 Nickel-Titanium Systems.

INTRODUCTION: This study evaluated the amount of apically extruded debris in the retreatment of curved root canals using different nickel-titanium (NiTi) systems: the ProTaper Universal Retreatment (Dentsply Maillefer, Ballaigues, Switzerland), Mtwo Retreatment (VDW, Munich, Germany), D-Race Retreatment (FKG Dentaire, La Chaux-de-Fonds, Switzerland), R-Endo Retreatment (Micro-Mega, Besançon, France), and Reciproc (VDW) systems. METHODS: One hundred human mandibular premolars with curved root canals were prepared with the Reciproc #25 .08 NiTi system filled with AH Plus Jet (Dentsply DeTrey, Konstanz, Germany) sealer and gutta-percha and divided into 5 groups (n = 20). The canal filling was removed with the ProTaper, Mtwo, D-Race, and R-Endo retreatment systems and Reciproc instruments. Final preparation was done with the Reciproc #40 .06 NiTi system. Extruded debris was collected in preweighed Eppendorf tubes. The times required for retreatment were recorded. RESULTS: Reciproc produced significantly (P < .001) more debris than the other systems. ProTaper R and Mtwo R produced significantly (P < .001) more debris than D-Race and R-Endo. The Reciproc group required significantly (P < .001) less preparation time than the other groups. CONCLUSIONS: In the retreatment of curved root canals, the Reciproc system extruded significantly more debris than the rotary retreatment NiTi systems. In addition, the ProTaper and Mtwo retreatment systems extruded significantly more debris than the R-Endo and D-Race systems. The Reciproc system was significantly faster than the rotary retreatment systems.

Effect of gaseous ozone and light-activated disinfection on the surface hardness of resin-based root canal sealers.

Although root canal instruments remove most of the content from the main root canal space, disinfection or irrigation plays an indispensable role in all areas of the root canal system, especially in parts that are inaccessible by instruments. The originality of this study was to investigate the effect of two novel disinfection techniques on the surface hardness of resin-based endodontic sealers using atomic force microscopy (AFM). Forty extracted single-rooted maxillary central human teeth were prepared and divided into four groups according to treatment methods. The first group was irrigated with saline and served as a control, other groups irrigated with sodium hypochlorite (NaClO); gaseous ozone; and light-activated disinfection (LAD). The groups were divided into two subgroups, according to the obturation method used: subgroup A: gutta-percha and AH plus; and subgroup B: EndoREZ/resin-coated cones. After obturation, atomic force microscopy (AFM) measurement was performed to analyze the surface hardness of the sealers. There was a significant difference between group 1A and group 3A (p < 0.05). Group 3B had the highest surface hardness values that were statistically different (p < 0.05). When disregarding the sealers, the ozone possessed statistically higher surface hardness values than the other groups in all root thirds (p < 0.05). The use of ozone and LAD may alter the surface hardness of resin-based sealers. The use of AFM can be considered an alternative hardness test techonology for sealing material.

Effect of Delayed Bonding and Antioxidant Application on the Bond Strength to Enamel after Internal Bleaching.

PURPOSE: This study evaluated the effect of delayed bonding and antioxidant application (AA, 10% sodium ascorbate) after internal bleaching (35% carbamide peroxide) on the shear bond strength of an adhesive cement to enamel. MATERIALS AND METHODS: Eighty-four human maxillary central incisors were endodontically treated. The control group remained unbleached with no AA. Experimental groups were all internally bleached. The buccal enamel was finished and polished with metallographic paper to a refinement of #600, in order to obtain a 5-mm(2) flat bonding area. An adhesive cement (Clearfil Esthetic) was placed into a plastic tube with internal diameter of 3 mm and a 3-mm height and cured on the enamel. Bonding occurred either immediately after bleaching (group Im), a 7-day delay (group 7), or a 14-day delay (group 14), and half the specimens were treated with antioxidant application (groups Im-AA, 7-AA, and 14-AA). Shear bond strength testing was performed on a universal testing machine, and data were analyzed with ANOVA and Fisher test (5%). RESULTS: Delaying of bonding is a useful factor for enhancing shear bond strength (p < 0.05), whereas AA only enhanced shear bond strength after 7 days delayed bleaching (p < 0.05). The highest bond strength was noted in groups 7-AA (20.51 ± 4.5 MPa), 14 (19.82 ± 4.6), 14-AA (20.27 ± 4.4), and control (20.51 ± 5.1), which were not significantly different from each other. CONCLUSIONS: After internal bleaching, adhesive cementation to enamel is recommended only when delayed 14 days, or delayed 7 days with sodium ascorbate application.

Do the Sealer Solvents Used Affect Apically Extruded Debris in Retreatment?

INTRODUCTION: We evaluated apically extruded debris in the retreatment of root canals filled with different root canal sealers and gutta-percha using different solvents. METHODS: Ninety human mandibular central and lateral teeth were prepared using the Reciproc #25 .08 nickel-titanium system (VDW GmbH, Munich, Germany) and were divided randomly into 6 groups. In groups 1, 2, and 3, root canals were filled with epoxy resin-based sealer and gutta-percha, and in groups 4, 5, and 6, root canals were filled with zinc oxide-eugenol-based sealer and gutta-percha. Each tooth was placed in a glass vial experimental apparatus. All root canal fillings were removed with the ProTaper Retreatment nickel-titanium system (Dentsply Maillefer, Ballaigues, Switzerland). During the retreatment procedure, in group 1, Resosolv (Pierre Rolland, Merignac, France) was used; in group 4, Endosolv E (Septodont, Paris, France) was used; and in groups 2 and 5, Guttasolv (Septodont) was used as the solvent. In the control groups (groups 3 and 6), no solvent was used. Reciproc #40 .06 was used for the final preparation. The times required for retreatments were recorded. RESULTS: The weight of the extruded debris and the time required for retreatment were decreased significantly in the groups in which a solvent that was intended specifically for the root canal sealer was used (groups 1 and 4). In the Guttasolv groups (groups 2 and 5), the amount of apically extruded debris and the time required decreased for both root canal sealers. CONCLUSIONS: The amount of apically extruded debris and the duration of retreatment were reduced by the use of a solvent specific to the sealer compared with a gutta-percha solvent or no solvent.

Evaluation of the resin cement thicknesses and push-out bond strengths of circular and oval fiber posts in oval-shapes canals.

PURPOSE: The aim of this study was to evaluate whether the push-out bond strength varies between oval and circular fiber posts, and to examine the effect on the resin cement thicknesses around the posts. MATERIALS AND METHODS: Eighteen mandibular premolar roots were separated into two groups for oval and circular fiber posts systems. Post spaces were prepared and fiber posts were luted to the post spaces. Roots were cut horizontally to produce 1-mm-thick specimens. Resin cement thicknesses were determined with a metallographic optical microscope and push-out tests were done. RESULTS: No significant differences were observed in terms of push-out bond strength between the oval and circular fiber posts (P>.05) The resin cement thicknesses of the oval posts were greater than those of the circular posts group in the coronal, middle and apical specimens (P<.05). CONCLUSION: In the light of these results, it can be stated that resin cement thickness does not affect the push-out bond strength.

The effect of residual calcium hydroxide on the accuracy of a contemporary electronic apex locator.

OBJECTIVE: The aim of this study was to evaluate the effect of residual calcium hydroxide [Ca(OH)2] on the accuracy of an electronic apex locator (EAL). MATERIALS AND METHODS: Working lengths (WLs) of 56 extracted maxillary incisors were determined initially by two different methods. The first method used the 'APEX' reading of the EAL as a reference point, 0.5 mm was subtracted and recorded as WL0. The second method used the '0.5' reading and the score was recorded as WL0.5 without subtraction. The roots were prepared to WL0 and divided randomly into three experimental groups (n = 16) (1 mm in group A, 2 mm in group B and 4 mm in group C) and a control (n = 8). Specimens in all experimental groups were filled with Ca(OH)2 paste. Following its removal, WLs were re-determined with the same methods. RESULTS: In group C, pre/post WLs were significantly different (p < 0.05). No significant difference was observed between the other experimental groups and the control group. CONCLUSION: Accuracy of EAL decreased proportionally with the amount of paste remaining at the ±0.5-mm tolerance level. Ca(OH)2 paste remnants may cause incorrect EAL readings.

Effects of physical and morphological properties of roots on fracture resistance.

OBJECTIVE: The aim of this study was to determine how physical and morphological properties affect the fracture resistance of roots, and which criteria are important for root specimen standardization in fracture resistance studies. MATERIALS AND METHODS: Seventy-five freshly extracted human canine teeth were selected. Crowns were sectioned from the cement-enamel junction and the root lengths were set at 16 mm. Then they were prepared up to ProTaper F3 file. Each root was numbered and data were obtained by measuring mesiodistal and buccolingual dimensions, volume, weight, and density. Tests for fracture strength were performed using an Instron Testing Machine (Instron Corp. MA, USA). The force was applied axially, angled at 45 degrees with a constant speed of 1 mm/min. For each sample, the force at the time of fracture was recorded in Newtons. Results were evaluated statistically using linear regression analysis. RESULTS: Volume and weight of the roots had more effect than mesiodistal or buccolingual dimensions on root fracture resistance. CONCLUSIONS: In root fracture resistance studies, volume or weight of the roots must be standardized when distributing roots to groups.

Efficacy of Two Irrigants Used with Self-Adjusting File System on Smear Layer: A Scanning Electron Microscopy Study.

Mechanical instrumentation of root canals produces a smear layer that adversely affects the root canal seal. The aim of this study was to evaluate efficacy of MTAD and citric acid solutions used with self-adjusting file (SAF) system on smear layer. Twenty-three single-rooted human teeth were used for the study. Canals were instrumented manually up to a number 20 K file size. SAF was used to prepare the root canals. The following groups were studied: Group 1: MTAD + 5.25% NaOCl, Group 2: 20% citric acid + 5.25% NaOCl, and Group 3: Control (5.25% NaOCl). All roots were split longitudinally and subjected to scanning electron microscopy. The presence of smear layer in the coronal, middle, and apical thirds was evaluated using a five-score evaluation system. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis. In the coronal third, Group 2 exhibited the best results and was statistically different froms the other groups (P < 0.05). There was not a significant difference among the three thirds of groups according to in-group comparisons (P > 0.05). The solutions used in Group 1 and 2 could effectively remove smear layer in most of the specimens. However, citric acid was more effective than MTAD in the three thirds of the canal.

Stress distribution of oval and circular fiber posts in amandibular premolar: a three-dimensional finite element analysis.

PURPOSE: The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs). MATERIALS AND METHODS: A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of 45° to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts. RESULTS: FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups. CONCLUSION: Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the post-dentin interface.

In vitro fracture resistance of endodontically treated roots filled with a bonded filling material or different types of posts.

AIM: This study aimed to compare the fracture resistance of roots filled with a bonded material, fiber posts, or titanium post systems. METHODS: Canals in the first group were filled with AH Plus and gutta-percha cones, and roots in the second group were filled with Epiphany sealer and Resilon cones. The root fillings (60 roots) were removed up to 4 mm from the canal apex to obtain 10-mm-deep post spaces, and posts were cemented. The groups were as follows: AH Plus control group, Epiphany control group, AH Plus fiber post group, AH Plus titanium post group, Epiphany fiber post group, and Epiphany titanium post group. Fracture tests were performed by using an Instron testing machine. The force was applied at a 45° axial angle with a constant speed of 1 mm/min. For each sample, the force at which fracture occurred was recorded in units of newtons. Statistical analysis was carried out by using analysis of variance test. RESULTS: There was no statistically significant difference between all groups (P > .05). CONCLUSIONS: Titanium posts, fiber posts, and Epiphany root canal filling systems were found to have no reinforcing effect on endodontically treated roots.

Apical extrusion of debris using self-adjusting file, reciprocating single-file, and 2 rotary instrumentation systems.

INTRODUCTION: The purpose of this study was to evaluate the weight of debris extruded apically from teeth using different in vitro preparation techniques. METHODS: Sixty-eight extracted human mandibular premolars with single canals and similar lengths were instrumented using ProTaper F2 (25, .08; Dentsply Maillefer, Ballaigues, Switzerland), the Self-Adjusting File (1.5-mm diameter; Re-Dent Nova, Ra'anana, Israel), Revo-S SU (25, .06; MicroMega, Besancon, France), or Reciproc (R25; VDW GmbH, Munich Germany). Debris extruded during instrumentation were collected into preweighed Eppendorf tubes. The Eppendorf tubes were then stored in an incubator at 70°C for 5 days. The Eppendorf tubes were weighed to obtain the final weight of the Eppendorf tubes when the extruded debris were included. Three consecutive weights were obtained for each tube. RESULTS: There were no statistically significant differences among the groups (P = .218). The ProTaper group produced the highest mean extrusion value. The Reciproc produced less debris compared with all the other instruments (P > .05). CONCLUSIONS: All instrumentation techniques were associated with extruded debris.

Determination of the effect of Nd:YAG laser irradiation through dentinal tubules on several oral pathogens.

The effects of Nd:YAG laser irradiations at different power settings on several oral pathogens were evaluated. A total of 252 dentin samples were divided into seven groups consisting of 36 dentin specimens each. In each group, 9 of the 36 specimens were used as controls, thereby including a control in every group. The remaining 27 specimens were divided into three subgroups consisting of nine specimens according to different Nd:YAG laser settings (1.5, 1.8, and 2 W). Each group was inoculated on the nonpulpal side with one of the following microorganisms: Candida glabrata, Candida tropicalis, Candida krusei, Candida sake, Candida lusitaniae, Candida kefyr, and Rhodotorula mucilaginosa. The following irradiation procedure was used: the specimens were irradiated on the bacteria-free side (the side consisting of the pulpal wall) using contact mode under the constant scanning movement of the optical fiber at an angle of 10°. One lasing cycle consisted of four irradiation cycles of 10 s each, with 15-s intervals in between each irradiation cycle. The remainder of the controls and the lased specimens of each group were prepared for the microbiological investigation. After incubation for 24 h at 37 °C, the colonies were counted, and the total number of surviving microorganisms was statistically assessed. Microorganisms irradiated with Nd:YAG laser at power settings 2 W, 15 pps did not survive. Although there was a significant reduction of microorganisms at 1.5 and 1.8 W, when comparing Nd:YAG laser irradiation with the control group, sterilization did not occur.

Infrared thermographic comparison of temperature increases on the root surface during dowel space preparations using circular versus oval fiber dowel systems.

PURPOSE: The purpose was to evaluate temperature increases during dowel space preparations with oval and circular fiber dowel systems. MATERIALS AND METHODS: This study included 42 single-rooted human mandibular premolars. Roots were scanned with cone-beam computerized tomography (CBCT) to determine the ovoid root canal morphology. Root canals were treated with Ni-Ti rotary instruments and obturated. A second CBCT was taken to determine the thinnest dentin thickness of each root. Roots were randomly divided into two groups (n = 21) according to the fiber dowel system used: group 1, circular fiber dowel system (D.T. Light-Post); group 2, oval fiber dowel system (Ellipson Post). Dowel spaces were prepared using a circular fiber dowel drill and a diamond-coated ultrasonic tip with an oval section under water cooling until 9 mm dowel spaces were obtained. Temperature changes were recorded from the thinnest root surfaces using a FLIR E60 thermal imaging camera. RESULTS: Temperature increases were significantly greater with the circular fiber dowel system than with the oval fiber dowel system (p < 0.05). CONCLUSIONS: Although both dowel systems generated high temperature increases on root surfaces, the relatively lower temperature increase associated with the use of oval fiber dowels in ovoid canals makes it preferable to the use of circular fiber dowels.

Effects of dissolving solutions on the accuracy of an electronic apex locator-integrated endodontic handpiece.

The effects of three dissolving agents on the accuracy of an electronic apex locator- (EAL-) integrated endodontic handpiece during retreatment procedures were evaluated. The true lengths (TLs) of 56 extracted incisor teeth were determined visually. Twenty teeth were filled with gutta-percha and a resin-based sealer (group A), 20 with gutta-percha and a zinc oxide/eugenol-based sealer (group B), and 16 roots were used as the control group (group C). All roots were prepared to TL. Guttasolv, Resosolv, and Endosolv E were used as the dissolving solutions. Two evaluations of the handpiece were performed: the apical accuracy during the auto reverse function (ARL) and the apex locator function (EL) alone. The ARL function of the handpiece gave acceptable results. There were significant differences between the EL mode measurements and the TL (P < 0.05). In these comparisons, Tri Auto ZX EL mode measurements were significantly shorter than those of the TL.

In vitro antimicrobial activity of propolis, BioPure MTAD, sodium hypochlorite, and chlorhexidine on Enterococcus faecalis and Candida albicans.

OBJECTIVE: To evaluate the antimicrobial effect by measuring the minimum inhibitory concentration MIC and minimum bactericidal concentration MBC of propolis, BioPure MTAD, 5% sodium hypochlorite (NaOCl), and 2% chlorhexidine CHX on Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans) in vitro. METHODS: This study was performed in the Faculty of Dentistry and Pharmacy at Erciyes University, Kayseri, Turkey from February to April 2010. Ethanol extract of propolis (EEP) was prepared from propolis collected from Kayseri, Turkey, and proper media for microorganisms were prepared using sterile broth medium to give final concentrations between 0.002-2.4 mg/ml for propolis, 0.000125-0.512 mg/ml for CHX, and 1:2-1:4096 dilutions for NaOCl and BioPure MTAD. Using the macrobroth dilution method, MIC, and MBC values of irrigants on the growth of E. faecalis and C. albicans were determined. RESULTS: Propolis and other irrigants were found to be effective on C. albicans and E. faecalis. Propolis and NaOCl were more effective in lower concentrations on C. albicans than on E. faecalis. In contrast, CHX and MTAD were more effective in lower concentrations on E. faecalis than on C. albicans. CONCLUSION: Propolis showed antimicrobial activity against E. faecalis and C. albicans. It appears that propolis is an effective intracanal irrigant in eradicating E. faecalis and C. albicans.