Ozgur Er

Solubility of root canal sealers with different organic solvents

OBJECTIVE The aim of this study was to assess the solubility of the new root canal sealer Epiphany and to compare it with 2 conventional sealers against 2 organic solvents commonly used in retreatment. STUDY DESIGN Standardized cylindric glass molds 5 mm wide and 2 mm high were filled with freshly mixed root canal sealers AH Plus, Ketac-Endo, and Epiphany. Samples were stored at 37 degrees C for 2 weeks. Each sample was immersed in chloroform or eucalyptus oil for 2 min, 5 min, and 10 min. The mean percentage loss of weight was determined for each material in each solvent and for each immersion period. RESULTS There were no significant differences at 2 and 5 min (P > .05) for all tested sealers in all immersed solvents. AH Plus and Epiphany sealers showed significantly higher solubilities (P < .05) in chloroform than in eucalyptus oil. Epiphany was the most soluble root canal sealer in both the solvents. Ketac-Endo was the least soluble sealer in both chloroform and eucalyptus oil at all exposure times (P < .05). CONCLUSION The root canal sealers Epiphany and AH Plus dissolved to some extent and more than Ketac-Endo, using either eucalyptus oil or chloroform as the solvent.

Can intracoronally bleached teeth be bonded safely

INTRODUCTION Our objective was to determine the effects of intracoronal bleaching on the shear bond strength and failure side location of metallic brackets at 2 times (bleaching immediately before bonding and 30 days before bonding). METHODS Sixty freshly extracted mandibular incisors were randomly divided into 3 groups; each group contained 20 teeth. After finishing canal preparation and root canal filling, the root fillings were removed to a level 2 mm apical to the cementoenamel junction. Glass ionomer base (Vitrabond, 3 M Dental Products, St Paul, Minn) was placed approximately 2-mm thick. Bleaching agent (Whiteness Perfect, FGM Dental Products, Joinville, Brazil) was placed into the rest of the cavity for 4 days at 2 times. Shear bond strength of these brackets was measured in megapascals. The adhesive remnant index (ARI) scores were determined after the brackets failed. Data were analyzed with analysis of variance (ANOVA), Tukey, and chi-square tests. RESULTS The bond strengths of the group with no bleaching (mean, 20.25 +/- 7.06 MPa) were significantly higher (P >0.001) than those of the group that had bleaching immediately before bonding (mean, 4.85 +/- 3.22 MPa) and the group that had bleaching 30 days before bonding (mean, 8.70 +/- 4.93 MPa). The results of the chi-square comparisons indicated significant differences among the 3 groups. In the group with no bleaching, there was a higher frequency of ARI scores of 2 to 4, indicating cohesive failures in the resin. In the other 2 groups, the failures were mostly adhesive at the resin-enamel interface (ARI scores of 4 and 5). CONCLUSIONS Intracoronal bleaching with carbamide peroxide adversely affected the shear bond strength and changed the site of failure during debonding when bonding was done immediately or 30 days after bleaching.

Radiographic Assessment of the Technical Quality and Periapical Health of Root-Filled Teeth Performed by General Practitioners in a Turkish Subpopulation

Aim. The aim of this study was to evaluate by means of radiographs the technical quality of root fillings performed by dental practitioners. Methods and Material. Standardized periapical radiographs were made on 484 patients who received endodontic treatment in private practice. A total of 831 endodontically treated teeth with 1448 roots were evaluated for technical quality of the root canal filling and the periapical status of the teeth. Also, the apical status of each root-filled tooth was assessed according to the length, density, and taper of root fillings, and the presence of apical transportation, broken root instruments, and overfilled sealer or gutta-percha material was recorded for each root canal. Results. Of the endodontically treated teeth 26.6% had healthy periapical tissues, while technically good endodontic treatment constituted 12.8%. Based on the treatment success, there was no significant difference between the tooth groups. Statistical analysis of the data did not demonstrate statistically significant differences between the various parameters that were evaluated (P < 0.05). Conclusions. Technical quality of root fillings in a population who received treatment in private practice was poor and was consistent with a low prevalence of apical health. The probable reasons for this failure are multifactorial and may be improved if the operators improve their skills with continuing postgraduate education programs.

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.

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.

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.

Classification of root canal microorganisms using electronic-nose and discriminant analysis

BackgroundRoot canal treatment is a debridement process which disrupts and removes entire microorganisms from the root canal system. Identification of microorganisms may help clinicians decide on treatment alternatives such as using different irrigants, intracanal medicaments and antibiotics. However, the difficulty in cultivation and the complexity in isolation of predominant anaerobic microorganisms make clinicians resort to empirical medical treatments. For this reason, identification of microorganisms is not a routinely used procedure in root canal treatment. In this study, we aimed at classifying 7 different standard microorganism strains which are frequently seen in root canal infections, using odor data collected using an electronic nose instrument.MethodOur microorganism odor data set consisted of 5 repeated samples from 7 different classes at 4 concentration levels. For each concentration, 35 samples were classified using 3 different discriminant analysis methods. In order to determine an optimal setting for using electronic-nose in such an application, we have tried 3 different approaches in evaluating sensor responses. Moreover, we have used 3 different sensor baseline values in normalizing sensor responses. Since the number of sensors is relatively large compared to sample size, we have also investigated the influence of two different dimension reduction methods on classification performance.ResultsWe have found that quadratic type dicriminant analysis outperforms other varieties of this method. We have also observed that classification performance decreases as the concentration decreases. Among different baseline values used for pre-processing the sensor responses, the model where the minimum values of sensor readings in the sample were accepted as the baseline yields better classification performance. Corresponding to this optimal choice of baseline value, we have noted that among different sensor response model and feature reduction method combinations, the difference model with standard deviation based dimension reduction or normalized fractional difference model with principal component analysis based dimension reduction results in the best overall performance across different concentrations.ConclusionOur results reveal that the electronic nose technology is a promising and convenient alternative for classifying microorganisms that cause root canal infections. With our comprehensive approach, we have also determined optimal settings to obtain higher classification performance using this technology and discriminant analysis.

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.

Farklı post boylarının ve farklı siman kullanımının kron ile restore edilmiş dişlerin kırılma dayanımına etkisi

Farkli post boylarinin ve farkli siman kullaniminin kron ile restore edilmis dislerin kirilma dayanimina etkisi Amac: Bu calismanin amaci post-kor ve kronla restore edilmis dislerde farkli simantasyon materyallerinin ve post uzunluklarinin kirilma direncine etkisini degerlendirmektir. Gerec ve Yontemler: Benzer boylara sahip 40 mandibular premolar disin kronlari uzaklastirildi. Kanal tedavileri yapildiktan sonra disler akrilik bloklara gomuldu. Ornekler ilk olarak ikiye ayrildi. 10 mm ve 5 mm derinliklerinde sirkuler post bosluklari, sirasiyla #0.5 ve #2 kodlu uretici frezleri ile hazirlandi. Post (D.T. Light-Post) simantasyonu asamasinda, her post grubundaki 10 ornek kendinden adezivli rezin siman (Rely X) ile simante edildi. Diger 10 ornek kendinden asitli kompozit siman (Clearfill Esthetic Cement) ile simante edildi (n=10). Tum ornekler kompozit korlar ile restore edildi ve toplamda yaklasik 5°’lik konverjans acisiyla 6 mm boyunda (1 mm ferrule dahil) prepare edildi. Sonra, tum disler tam metal kronlarla, cam iyonomer simanla simante edilerek restore edildi. Termal dongu ile yorma sonrasi, tum orneklere kirilma dayanimi testi (0,5 mm/min) uygulandi. Data iki yonlu varyans analizi kullanilarak analiz edildi (α=0.05). Bulgular: Farkli tip siman kullanimi restore edilmis dislerin kirilma dayanimini etkilemezken (p=0.209), 10 mm derinlikte post yerlesimi 5 mm derinlikte yerlesime gore daha yuksek kirilma dayanimi gostermistir (p<0.001).Sonuc: Calismanin limitasyonlari dahilinde, hangi tip simanin kullanildigina bakilmaksizin, post boslugunun daha derin acilmasi post-kor destekli kron restorasyonlu dislerin kirilma dayanimini artirmaktadir.

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.