Finite element evaluation of dentin stress changes following different endodontic surgical approaches.

The aim was to compare the effect of different endodontic surgical treatments on the stress distributions in dentin of a simulated first mandibular molar tooth using the finite element analysis method. Three surgical endodontic procedures (apical resection, root amputation, and hemisection) were simulated in a first mandibular molar. Biodentine or mineral-trioxide-aggregate was used to repair the surgery site in apical resection and root amputation models; the remaining root canal spaces were filled with gutta-percha. Access cavities were restored using resin composite. In hemisection model, root canal was filled with gutta-percha, and coronal restoration was finished with a monolithic zirconia crown. A sound tooth model was created as a control model. An oblique force of 300 N angled at 45° to the occlusal plane was simulated. Maximum von Mises stresses were evaluated in dentin near the surgery regions and the entire tooth. Apical resection/Biodentine and apical resection/mineral-trioxide-aggregate models generated maximum von Mises stresses of 39.001 MPa and 39.106 MPa, respectively. The recorded maximum von Mises stresses in root amputation models were 66.491 MPa for root amputation/Biodentine and 73.063 MPa for root amputation/mineral-trioxide-aggregate models. The highest maximum von Mises stress value among all models was observed in the hemisection model, measuring 138.87 MPa. Hemisection induced the highest von Mises stresses in dentin, followed by root amputation and apical resection. In apical resection, Biodentine and mineral-trioxide-aggregate did not show a significant difference in stress distribution. Biodentine in root amputation may lead to lower stresses compared to mineral-trioxide-aggregate.

Rational design of EDTA-incorporated nanoflowers as novel and effective endodontic disinfection against biofilms.

The ethylenediaminetetradiacetic acid (EDTA) is one of the most commonly used irrigation solutions. Although EDTA has a very low antimicrobial property, it is used to remove inorganic part of smear layer in areas of root canal system. Herein, we developed EDTA-incorporated nanoflowers (EDTA NFs), for the first time, as novel and effective irrigation solution with quite high antimicrobial property to provide complete disinfection in root canal system. We both systematically elucidated the formation of the EDTA NFs with various techniques, and their catalytic and antimicrobial activities in the presence of hydrogen peroxide (H2O2) were documented through intrinsic EDTA property and peroxidase-like activities.

Comparison of the effect of different glide path files on amount of apically extruded debris in curved root canals.

It is essential to create a glide path before root canal preparation with nickel-titanium rotary files to avoid file breakage and preserve the original canal structure. The aim of this study was to compare the amount of apically extruded debris after using different glide path files. A total of 96 first mandibular molars with curved mesial roots were randomly divided into six groups (n = 16) which are K-files, Proglider, R-Pilot, TruNatomy Glider, WaveOne Gold Glider and group without a glide path. Apically extruded debris was measured after glide path and canal preparation. The highest amount of debris was found in the control group without a glide path and using a glide path file caused less debris and significant differences were observed between R-Pilot, TruNatomy Glider, ProGlider, WaveOne Gold Glider and K-file groups. It may be recommended to create a glide path before root canal shaping to reduce the amount of extrusion debris from the apical. Especially in curved and narrow root canals, it is recommended to use an R-Pilot file before root canal shaping in order to reduce the amount of apically extruded debris.

Amplicon-based next-generation sequencing for comparative analysis of root canal microbiome of teeth with primary and persistent/secondary endodontic infections.

OBJECTIVES: To compare the root canal microbiome profiles of primary and persistent/secondary infections using high-throughput sequencing with the help of a reliable bioinformatics algorithm. MATERIALS AND METHODS: Root canal samples of 10 teeth in the primary endodontic infection (PEI) group and 10 teeth in the persistent/secondary endodontic infection (SEI) group were included resulting in a total of 20 samples. After DNA extraction from the samples, sequencing was performed on the Illumina MiSeq platform. Pair-end Illumina reads were imported to QIIME 2; amplicon sequence variants (ASVs) generated by DADA2 were mapped to GreenGenes database. Weighted UniFrac distances were calculated and principal coordinates analysis (PCoA) was used to compare beta diversity patterns. The multiple response permutation procedure (MRPP), the analysis of similarities (ANOSIM), and permutational multivariate analysis of variance (adonis) were conducted for testing group differences. Linear discriminant analysis effect size (LEfSe) analysis was utilized to identify differentially abundant taxa between the groups. The linear discriminant analysis (LDA) score threshold was set to 4.0. RESULTS: Within the Gram-negative facultative anaerobic Gammaproteobacteria class outgroup, two orders (Pasteurellales, Vibrionales) and two families (Pasteurellaceae, Vibrionaceae) were significantly more abundant in the PEI group, whereas Gram-positive bacteria, Actinomycetales order, and Gram-positive anaerobic taxa, one genus (Olsenella) and one species (Olsenella uli), were identified as significantly more abundant in the SEI group. CONCLUSIONS: A few taxa were differentially abundant within either the PEI or SEI group. CLINICAL RELEVANCE: Reliable bioinformatic tools are needed to define microbial profiles of endodontic infections. Based on a limited number of samples, no distinct variation was determined between the bacterial diversity of initial and recurrent endodontic infections.

Evaluation of ultrasonography as a diagnostic tool in the management of periapical cysts and granulomas: A clinical study.

Purpose: The aim of this study was, firstly, to determine the concordance of ultrasonographic and histopathological diagnoses in patients in whom apical resection was already indicated. Secondly, this study aimed to determine whether lesions were periapical granulomas or cysts, and to compare them after root canal treatment using ultrasonography and periapical radiographs. Materials and Methods: In the first stage of the study, ultrasonographic and histopathologic diagnoses of 10 lesions were compared. Secondly, the periapical radiographs and ultrasonographic images of 44 lesions were measured. The presence of internal vascularity was determined by ultrasonographic color and power Doppler modes. Follow-up examinations of healing after root canal treatment were performed using ultrasonography and periapical radiographs, and these modalities were compared. Results: In the periapical granuloma and cyst groups, the measurement values decreased for all variables. There was no significant difference in the dimensional changes of lesions between the 2 groups, and ultrasonography and periapical radiographs were compatible. The pre-diagnoses were compared with histopathological diagnoses and were found to be compatible. Conclusion: The ultrasonographic color and power Doppler techniques could be an effective method for diagnosing periapical lesions as cysts or granulomas. After root canal treatment of granulomas and cysts, the dimensional shrinkage and healing patterns appear to be similar. Ultrasonography and periapical radiographs were consistent in terms of dimensional comparisons, and ultrasonography may be an alternative method for follow-up of the healing of periapical lesions.

Evaluation of Stress Distributions in Mandibular Molar Teeth with Different Iatrogenic Root Perforations Repaired with Biodentine or Mineral Trioxide Aggregate: A Finite Element Analysis Study.

INTRODUCTION: In this study, finite element analysis was used to evaluate the stress distributions in simulated mandibular molar teeth with various iatrogenic root perforation types after reparation with Biodentine (Septodont, Saint-Maur-des-Fossés, France) or mineral trioxide aggregate (MTA). METHODS: An extracted human mandibular molar tooth was scanned using a micro-computed tomographic device, and a 3-dimensional solid model was created. Then, 3 different iatrogenic perforation types (furcation perforation [FP], strip perforation [SP], and post drill perforation [PDP]) and 2 different repair materials (MTA and Biodentine [BD]) were simulated on the model. In addition, a sound tooth (ST) model (control) and a model left unrepaired for each type of perforation were created; then, access cavities were restored using resin composite, except for the sound tooth model. Consequently, a total of 10 experimental models were designed. An oblique force of 300 N angled at 45° to the occlusal plane was simulated. Evaluations of von Mises stress were performed in the perforated regions. RESULTS: Maximum von Mises stress values were 7.76 MPa for ST/corresponding to the FP region, 8.48 MPa for ST/corresponding to the SP region, 14.20 MPa for ST/corresponding to the PDP region, 10.89 MPa for FP /MTA, 7.65 MPa for FP/BD, 14.67 MPa for FP/unrepaired, 15.92 MPa for SP/MTA, 15.82 MPa for SP/BD, 21.95 MPa for SP/unrepaired, 10.20 MPa for PDP/MTA, 9.17 MPa for PDP/BD, and 17.86 MPa for PDP/unrepaired. CONCLUSIONS: The results of this finite element analysis indicated that BD models showed lower maximum von Mises stress values than the MTA models, and SPs exposed higher stress concentrations in root perforation regions than FPs and PDPs. The use of MTA and BD may reduce the risk of potentially harmful stress in root perforation regions.

Ex Vivo Evaluation of the Accuracy of 3 Electronic Apex Locators in Different Environments: A Micro-Computed Tomography Study.

OBJECTIVE: The aim of this study was to compare the accuracy of three electronic apex locators (EALs) (Propex Pixi, Mini Root ZX, Raypex 5) in determining working length (WL) under different environments (existence of blood-pulp/sodium hypochlorite in root canal space) using micro-computed tomography (micro-CT) measurements. METHODS: Twenty-five single-rooted human teeth that were scheduled for extraction were selected for the study. Measurements were performed with the Propex Pixi, Mini Root ZX, Raypex 5 in vivo conditions in the presence of NaOCl irrigant solution or blood-pulp tissue. After that the teeth were extracted and scanned using micro-CT. The measurements of WL obtained with the different EALs in different environments were statistically compared. Significance was set at P<0.05. RESULTS: There were no significant differences among the WL measurements performed with EALs or micro CT groups under different clinical enviroments. All EALs tested gave reliable results in respect to apical constriction. CONCLUSION: The accuracy of the tested EALs is not affected by pulp tissues and blood or NaOCl.

Effect of Sterilization on Bond Strength and Mechanical Properties of Fiber Posts.

PURPOSE: To determine the effects of two different sterilization methods on the pull-out bond strength, flexural strength, and elastic modulus of glass-fiber posts. MATERIALS AND METHODS: A total of 69 glass-fiber posts were used. The posts were divided into three groups according to applied sterilization method: 1) control, 2) ethylene oxide gas (EOG), and 3) autoclave. The microstructure of three posts from each group was evaluated by SEM and energy-dispersive X-ray spectroscopy (EDS). Thirty glass-fiber posts were used to evaluate pull-out bond strength. The three-point bending test was performed to analyze the flexural strength on another 30 glass-fiber posts. Failure modes were categorized microscopically after the pull-out test. After the three-point bending test, micromorphology at the bending area was examined using SEM. RESULTS: One-way ANOVA indicated no statistically significant differences among the group means in terms of bond strength (p > 0.05), flexural strength (p > 0.05), or elastic modulus (p > 0.05). EDS revealed that the weight percentage of surface oxygen atoms in the EOG- and autoclave-sterilization groups were significantly higher. SEM images were similar. CONCLUSION: The results of this study show that glass-fiber posts can be sterilized either by autoclave or EOG when necessary, without any negative effect on bond strength, flexural strength, or elastic modulus.

Stress distributions in internal resorption cavities restored with different materials at different root levels: A finite element analysis study.

The aim of this study was to evaluate the stresses within simulated roots with internal resorption cavities at the apical, middle and coronal root levels, after obturation with gutta-percha and/or MTA utilising finite element analysis (FEA). Mandibular premolar teeth with internal resorption cavities at different root levels were modelled. Models were restored with gutta-percha and/or MTA. An oblique force of 300 N was applied and stress evaluations were carried out. In the MTA-filled resorption models, the stresses were distributed more homogeneously than the gutta-percha filled models, and the stress concentrations were lower in the remaining dentinal tissues. If the whole root is considered, the fully gutta-percha-filled models generated the highest stress values. Differences between the fully MTA-filled models and hybrid techniques were present only in the apical resorption models. Both the MTA and combination of MTA and gutta-percha can be suggested for use in clinical practice, in cases of internal root resorption cavity obturation.

The effects of different desensitizer agents on shear bond strength of orthodontic brackets after home bleaching: an in vitro study.

PURPOSE: The aim of this study was to test the null hypothesis that no difference exists between shear bond strength values of control and bleaching plus desensitizer applied groups. MATERIALS AND METHODS: A hundred freshly extracted human premolar teeth were randomly divided into five groups. Group I served as the control group with no bleaching application, while only bleaching was achieved in Group II. Desensitizer containing potassium nitrate-fluoride and casein phosphopeptide amorphous calcium phosphate were applied in Groups III and IV, after bleaching respectively. A bleaching agent containing amorphous calcium phosphate was used in Group V. Shear bond strength tests were carried out using a universal testing machine (Instron Corp., Norwood, MA, USA). Remnant adhesive on the teeth and brackets was examined to score the adhesive remnant index. Kruskal-Wallis and Chi-Square tests were used for statistical analysis of the data. RESULTS: Statistically significant differences were found among the groups for shear bond strength values (p<.001). The shear bond strength of Group III (8.0±2.2 MPa) was significantly lower than the other groups (p<.05). The highest shear bond strength values were found for Group I (13.6±3.7 MPa) and Group IV (12.8±4.0 MPa). No statistically significant difference was observed between Group II (10.0±2.7 MPa) and Group V (10.8±2.9 MPa). The differences between adhesive remnant index scores of the groups were not statistically significant. CONCLUSION: Casein phosphopeptide amorphous calcium phosphate gel application showed a similar shear bond strength value to the control group, while shear bond strength values decreased after using other desensitizers.

Effect of double antibiotic and calcium hydroxide pastes on dislodgement resistance of an epoxy resin-based and two calcium silicate-based root canal sealers.

OBJECTIVES: The purpose of the present study was to determine the dislodgement resistance of AH Plus, MTA Fillapex, and Total Fill BC sealer to root canal dentin walls following placement of calcium hydroxide (CH) or double antibiotic paste (DAP) medicaments. MATERIALS AND METHODS: Root canals of 90 single-rooted human mandibular premolar teeth were instrumented with Reciproc rotary instruments to a size R50. The teeth were randomly divided into two experimental groups: those receiving an intracanal medicament with either CH or DAP and a control group (n = 30). After 3 weeks, the medicaments were removed by irrigation with 5 mL of 2.5 % NaOCl, 5 mL 17 % EDTA, and 5 mL distilled water under sonic agitation. Each group was then subdivided into three subgroups (n = 10), and the canals were filled with either AH Plus, MTA Fillapex, or Total Fill BC sealer. After 1 week, a push-out test was applied to the specimens and the results were analyzed using one-way analysis of variance (ANOVA) and post hoc Tamhane's tests. RESULTS: Regardless of the type of intracanal medicament used, Total Fill BC Sealer and MTA Fillapex showed the highest and lowest bond strength, respectively (P < 0.05). The use or absence of medicaments did not significantly affect the dislodgment resistance of root canal fillings (P > 0.05). Prior CH placement improved dislodgement resistance of all sealers without statistical difference (P > 0.05). Adhesive failure between core and sealer was the most frequent failure mode. CONCLUSIONS: Prior application of CH or DAP did not significantly affect the adhesion of the AH Plus, MTA Fillapex, and Total Fill BC Sealers. CLINICAL RELEVANCE: There is a little information about the influence of antibiotic medicaments on the bond strength of root canal sealer. These findings suggest that the use of DAP does not affect the adhesion strength of AH Plus, MTA Fillapex, and Total Fill BC Sealers.

Evaluation of the Reliability of Cone-beam Computed Tomography Scanning and Electronic Apex Locator Measurements in Working Length Determination of Teeth with Large Periapical Lesions.

INTRODUCTION: This study evaluates the endodontic working-length measurements in teeth with large periapical lesions and persistent intracanal exudate by using preexisting cone-beam computed tomography (CBCT). It compares the measurements with clinical root canal lengths determined by using 2 electronic apex locators. METHODS: All patients had undergone a CBCT scan independent of the present study and needed root canal treatment of at least 1 tooth visible in the field of view. Seventy-three teeth with single roots and canals were studied. An endodontist measured each root canal length with 2 different electronic apex locators. The measurements were repeated 3 times by using a digital caliper, and the mean was recorded. This mean was compared with the root canal length as measured on CBCT sections by an oral radiologist not involved in the endodontic treatment. The CBCT measurements were taken twice for analysis of intrarater reliability. The data were statistically analyzed. RESULTS: There were no significant measurement differences between the methods used (P > .05). CONCLUSIONS: In teeth with large periapical lesions and persistent intracanal exudate, measurement of the root canal length by using CBCT was as reliable as measurements that used apex locators.

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.

The effect of blood contamination on dislocation resistance of different endodontic reparative materials.

This study evaluated the retention characteristics of ProRoot mineral trioxide aggregate (MTA), RetroMTA, Supra MTA, and Biodentine biomaterials used to repair furcation perforations contaminated with blood. Furcal perforations measuring 1.3 mm in diameter and 2 mm in height were created in 96 mandibular first molar teeth, which were then randomly divided into the following two groups (n = 48): contaminated (+) or non-contaminated (-) with blood. The groups were subdivided into four groups (n = 12) according to the material used (ProRoot MTA, RetroMTA, Supra MTA, and Biodentine) to seal the perforations. The samples were allowed to set for 14 days and were then subjected to push-out testing. The results were analyzed using ANOVA, and the failure modes were examined using a surgical microscope. ProRoot MTA (+/-) and RetroMTA (+/-) exhibited superior bond strength values; in addition, there were no significant differences among these groups (P > 0.05). Biodentine (+) showed intermediate values that were sometimes statistically similar to the ProRoot MTA (+/-) and RetroMTA (+/-) groups (P > 0.05) and, at other times, the Biodentine (-) and Supra MTA (+/-) groups (P > 0.05). The lowest bond strength values were shown by the Biodentine (-) and Supra MTA groups (P > 0.05). "Adhesive failure mode" was the most frequently observed type for all tested materials. Blood contamination did not affect the dislocation resistance of materials.

The effects of different nickel-titanium instruments on dentinal microcrack formations during root canal preparation.

OBJECTIVE: The aim of the present study was to investigate the incidence of dentinal microcracks caused by different preparation techniques. MATERIALS AND METHODS: 120 extracted human mandibular incisor teeth were divided into five experimental groups and one control group (n = 20): Group 1: Hand preparation with balanced force technique up to #25 K-file. Group 2: Preparation with only ProTaper F2 instrument in a reciprocating movement. Group 3: Preparation with Reciproc R25 instrument in a reciprocating movement. Group 4: Preparation with ProTaper instruments up to F2 instrument. Group 5: Preparation with ProTaper Next instruments up to X2 instrument. No procedure was applied to control group. The roots were sectioned horizontally at 3, 6 and 9 mm from the apex and examined. Absence or presence of dentinal microcracks was noted. RESULTS: The Chi-square test was performed to compare the appearance of cracked roots between all groups. There were no significant differences among the groups (P > 0.05). CONCLUSIONS: In conclusion, except the hand file and control group, all experimental groups showed microcrack formations.

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.

Comparison of osteoconductive properties of three different ß-tricalcium phosphate graft materials: a pilot histomorphometric study in a pig model.

AIMS: The aim of this study was to compare the de novo bone formation ability and osteoconductive effects of three different ß-tricalcium phosphate (ß-TCP) graft materials. The micro-architectural parameters of the newly formed bone tissues were also compared among the different graft materials. MATERIAL AND METHODS: Eight male Swiss domestic pigs were used in the study. Five bony defects were made with a trephine bur. Three of the defects were filled with Cerasorb®, Kasios® and Poresorb®. The fourth defect was filled with an autogenous bone graft. The last defect remained empty. All subjects were sacrificed after 8 weeks. RESULTS: When compared to a negative control group, significant healing was observed in all the groups except the Cerasorb group. The osteoconductivity of the Poresorb group was better than that of the other groups (p < 0.05). The difference in the osteoconductivity of the Kasios and Cerasorb groups was statistically significant (p < 0.05). Comparison of the micro-architectural properties of newly formed bone tissues retrieved from the defects showed that those filled with Poresorb were the best. CONCLUSION: ß-TCP materials show different results in terms of the volume and characteristics of new bone formation, although they have a similar chemical structure.

Effects of zoledronic acid on physiologic bone remodeling of condylar part of TMJ: a radiologic and histomorphometric examination in rabbits.

OBJECTIVE: The purpose of the present study is to evaluate the effects of systemically administered zoledronic acid (ZA) on the physiological bone remodeling and the microarchitectural parameters of the condylar part of TMJ in a rabbit model. STUDY DESIGN: Thirty skeletally mature male New Zealand white rabbits were randomly divided into two groups. The experimental group was administered an intravenous, single dose of 0.1 mg/kg ZA diluted with 15 mL of saline in a 15-minute perfusion with an infusion pump. The control group was administered only saline infusion for 15 minutes. All rabbits were sacrificed on the 21st postoperative day. Radiodensitometric and histomorphometric examinations were performed on the harvested mandibular condyles. The data were analyzed statistically. RESULTS: Radiodensitometric findings showed that ZA treatment resulted in a significant increase in the mineralization of mandibular condyle. This result was supported by the histomorphometric findings. CONCLUSION: The present study has revealed that a temporary delay in the physiological bone remodeling using single dose of ZA increases bone mineral content and makes the microarchitecture of the mandibular condyle more compact. These effects may be regarded as base data and considered in numerous clinical situations including TMJ.

Outcomes of periradicular surgery of maxillary first molars using a vestibular approach: a prospective, clinical study with one year of follow-up.

PURPOSE: The aim of the present prospective, randomized, controlled, clinical study was to compare the outcomes of periradicular surgery of the maxillary first molar tooth using the vestibular approach between 2 preoperative radiologic evaluation methods: cone beam computed tomography (CBCT) and conventional radiography. PATIENTS AND METHODS: Periradicular surgery was applied to the maxillary first molar tooth in 40 patients. The patients were divided into 2 groups. The patients in group 1 underwent examination and preoperative planning with CBCT, and the patients in group 2 underwent examination and preoperative planning with conventional radiography. The outcomes of the treatment were evaluated radiographically and clinically, and the data were analyzed statistically. RESULTS: The mean operative time was significantly shorter in group 1 than in group 2. According to the radiographic and clinical healing criteria used in the present study, the healing of patients in group 1 was rated as a success in 35%, an improvement in 40%, and a failure in 25%. In the group 2 patients, healing was rated as a success in 42.1%, an improvement in 31.6%, and a failure in 26.3%. Sinus membrane elevation was performed in 92.3% of all patients. Sinus membrane perforation occurred in 20% of the patients in group 1 and 36.8% of the patients in group 2. CONCLUSIONS: Periradicular surgery of maxillary first molars using a vestibular approach is a viable treatment method with a low complication rate. Preoperative CBCT examination demonstrated positive contributions to the treatment outcomes.

Effects of calcium hydroxide and propolis intracanal medicaments on bond strength of resin-based endodontic sealer as assessed by push-out test.

The aim of this study was to investigate the effects of calcium hydroxide (Ca(OH)2) and propolis intracanal medicaments on bond strength of AH Plus to root dentin. After chemomechanical instrumentation using Revo-S rotary system, three groups of root canal specimens were prepared: 10 root canals were left untreated as controls (G1), 10 received Ca(OH)2 intracanal medicament (G2), and another 10 received propolis intracanal medicament (G3). Canals were obturated with AH Plus and gutta-percha. After bond strength evaluation using micro push-out test, data were analyzed using ANOVA and Tamhane's test (p=0.05). At coronal and middle thirds, there were no significant differences in bond strength among the three groups (p>0.05). At apical third, G3 was significantly superior to G2 (p<0.05) and G1 (p<0.05), but there was no significant difference between G2 and G1 (p>0.05). Therefore, when AH Plus was used as the sealer in endodontic treatments, its combined use with propolis as an intracanal medicament seemed to result in favorable sealer-dentin interfacial bond strength.