Anatomical and histological studies of the alimentary canal of adult maize leaf weevil,Tanymecusdilaticollis Gyllenhal, 1834 (Coleoptera: Curculionidae)

In this study, ananatomical and histological study was conducted on the alimentary canal of Tanymecusdilaticollis (Coleoptera: Curculionidae), which is an economic polyphagous pest species, to study the relationship between the structure of the alimentary canal and the feeding habit. Therefore, the structure of the alimentary canal of T. dilaticollis was examined using light and electron microscopies. Results have shown that the alimentary canal in T. dilaticollis is consisted of three separate regions as foregut, midgut, and hindgut structurally between the mouth and the anus, which pass from head, thorax, and abdomen. The foregut consists of pharynx, esophagus, crop and proventriculus and in the crop part, expansion is seen compared to other foregut parts. Midgut of T. dilaticollis is the largest part of digestion system. The anterior region of midgut is twofolds wider than the posterior region. The posterior midgut extends tubularly and it is connected to eightgastric caeca. The hindgut of T. dilaticollis consists of fourparts as pylorus, ileum, colon, and rectum. Well‐developed muscle layers are found near the rectum and genital chamber. These results contribute to further studies on the ecology and biological control agents of Coleoptera and to provide a broad comparison of alimentary canal of Coleoptera species.     

Micro‐Computed Tomography and Scanning Electron Microscopy Comparisons of Two Nickel–Titanium Rotary Root Canal Instruments Used With Reciprocating Motion

The single‐file root canal instrumentation technique using reciprocating motion has been gaining concern. Therefore, the purpose of this study was to compare the shaping ability of single ProTaper F2 file and WaveOne Primary file when they were used in the curved root canal with reciprocation motion and to investigate the durability of the file after use with a scanning electron microscopy (SEM). Changes in structure model index (SMI), root canal volume, curvature, surface area, and degree of transportation were measured from the cross‐sectional images of the prepared canals using the micro‐CT system with an isotropic resolution of 16 μm. Results showed that there were no differences in the changes of root canal volume, surface area, and SMI between the two file groups after the preparation (p > 0.05). The ProTaper group showed a curvature straightening value of 25.45 ± 12.51%, while the WaveOne group showed 27.30 ± 10.91%, and there was no statistically significant difference (p > 0.05). The transportation values between the two groups showed no significant differences (p > 0.05). SEM revealed that 60% of ProTaper files showed initiation of microcracks on the surface while those were detected on the only one WaveOne file. The single‐file technique using either WaveOne Primary or ProTaper F2 can be safely used under each reciprocating motion without creating an increased apical transportation in curved canals. However, the metallurgic property resists cyclic fatigue was more favorable with WaveOne under the scanning evaluation. SCANNING 35: 112‐118, 2013. © 2012 Wiley Periodicals, Inc.     

Computed microtomography evaluation of calcium hydroxide‐based root canal dressing removal from oval root canals by different methods of irrigation

The aim of this study was to evaluate the capacity of conventional irrigation, passive ultrasonic irrigation (PUI), and Easy Clean for removing calcium hydroxide‐based root canal dressing from oval root canals. Thirty mandibular uniradicular incisors with oval canals were used, and subjected to chemical–mechanical preparation with Reciproc R40 instruments. The main canal was filled with a paste based on Ca(OH)₂ P.A., iodoform and propylene glycol in the ratio of 3:1:1. The teeth were stored in 100% humidity at a temperature of 37°C for 14 days. Afterwards, the teeth were divided into three groups (n = 10) according to the method of irrigation used (conventional irrigation, PUI, and Easy Clean). The specimens were analyzed by computed microtomography at three time intervals: before placing the root canal dressing, with the root canal dressing in place, and after application of the irrigation methods for removing it. The data were submitted to Kruskal–Wallis and Dunn tests for analyzing the canal as a whole, and Friedman and Dunn for analyzing the root thirds. The results showed that conventional irrigation was less efficient for removing the root canal dressing in comparison with the methods that agitated the irrigant solution (p < .05). When the root canal was analyzed as a whole, Easy Clean, and PUI were similar (p > .05). In analysis of the thirds, Easy Clean was more efficient than conventional irrigation in all the thirds, while PUI showed this behavior only in the cervical third (p < .05). The authors concluded that in oval canals, none of the irrigation methods were capable of removing all the root canal dressing, however, the methods that agitated the irrigant solution were more efficient than conventional irrigation.     

Clinical microscopic analysis of protaper retreatment system efficacy considering root canal thirds using three endodontic sealers

To evaluate the efficacy of ProTaper Universal rotary retreatment system and the influence of sealer type on the presence of filling debris in the reinstrumented canals viewed in an operative clinical microscope. Forty‐five palatal root canals of first molars were filled with gutta‐percha and one of the following sealers: G1, EndoFill; G2, AH Plus; G3, Sealapex. The canals were then reinstrumented with ProTaper Universal rotary system. Roots were longitudinally sectioned and examined under an operative clinical microscope (10×), and the amount of filling debris on canal walls was analyzed using the AutoCAD 2004 software. A single operator used a specific software tool to outline the canal area and the filling debris area in each third (cervical, middle, and apical), as well as the total canal area. Data were analyzed by Kruskal‐Wallis test and Tukey test at P < 0.05. Sealapex demonstrated significant differences in the average of filling debris area/canal among the 3 thirds. This group revealed that apical third showed more debris than the both cervical and middle third (P < 0.0001). Endofill presented significantly more filling debris than Sealapex in the cervical third (P < 0.05). In the middle (P = 0.12) and apical third (P = 0.10), there were no differences amongst groups. Debris was left in all canal thirds, regardless of the retreatment technique. The greatest differences between techniques and sealers were found in the cervical third. Microsc. Res. Tech. 75:1233–1236, 2012. © 2012 Wiley Periodicals, Inc.     

Efficacy of different final irrigant activation protocols on smear layer removal by EDTA and citric acid

The aim of this study was to evaluate the influence of different activation protocols for chelating agents used after chemo‐mechanical preparation (CMP), for smear layer (SL) removal. Forty‐five single‐rooted human premolars with straight canals and fully formed apex were selected. The specimens were randomly divided into three groups depending on the chelating agent used for smear layer removal: distilled water (DW, control group); 17% ethylenediaminetetraacetic acid (EDTA); and 10% citric acid (CA). Each group was further divided into three subgroups according to the activation protocol used: no‐activation (NA), manual dynamic activation (MDA), or sonic activation (SA). After CMP, all specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy (SEM). Two calibrated evaluators attributed scores to each specimen. The differences between activation protocols were analyzed with Kruskal‐Wallis and Mann‐Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. When chelating agents were activated, either by MDA or SA, it was obtained the best cleaning results with no significant difference between EDTA and CA (P > 0.05). Sonic activation showed the best results when root canal thirds were analyzed, in comparison to MDA and NA groups (P < 0.05). The activation of chelating agents, independent of the protocol used, benefits smear layer removal from root canals. Microsc. Res. Tech. 76:364–369, 2013. © 2013 Wiley Periodicals, Inc.     

Comparison between the use of thermoplasticized gutta‐percha and a polydimethyl siloxane‐based material in filling internal resorptive cavities using spiral computed tomography

To evaluate the fill of internal resorption cavities obturated with thermoplasticized gutta‐percha and GuttaFlow2 using CT scan. Twenty human maxillary anterior teeth were selected and root canals were prepared using ProTaper system to size F3. Irrigation was performed with 5 ml of 2.5% sodium hypochlorite (NaOCl) and 5 ml of 17% ethylenediaminetetraacetic acid (EDTA). Each root was then sectioned horizontally into two halves and semicircular cavities were prepared around the periphery of the root canal opening of each root half, using a round bur. Both the root halves were then fixed using cyanoacrylate glue. All the specimens were subjected to preoperative CT scan analysis to determine the volume of internal cavities. The samples were then randomly divided into two groups. In Group 1, the specimens were obturated with thermoplasticized gutta‐percha (E&Q system) and specimens in Group 2 were obturated using GuttaFlow2. All specimens were then subjected to postoperative CT scan analysis. The volume of voids in internal resorptive cavities were calculated, which was then used to estimate the amount of gutta‐percha filled. There was no significant difference in volume of internal resorptive cavities between thermoplasticized gutta‐percha and GuttaFlow2 groups before obturation (p = 0.466). However, after obturation there was a significant difference between both the groups, in which GuttaFlow2 demonstrated better fill (p = .014). Thermoplasticized gutta‐percha filled 81% of internal resorptive cavity while GuttaFlow2 filled 91%, respectively. GuttaFlow2 showed better fill than thermoplasticized gutta‐percha in the filling of internal resorptive cavities.     

Evaluation of epoxy resin sealer after three root canal filling techniques by confocal laser scanning microscopy

The aim of this study was to evaluate the penetration of endodontic sealer into the dentin tubules, the integrity of the sealer layer perimeter, and the sealer area at the apical third after different filling techniques by confocal laser scanning microscopy (CLSM). Forty‐five mandibular premolars were mechanically prepared with ProTaper files, until F5 file. Thereafter, they were filled with an epoxy‐resin sealer (AH Plus) mixed with Rhodamine B dye (0.1% proportion) and allocated in three groups: Group 1, single master cone; Group 2, cold lateral compaction; and Group 3, Thermafil. For confocal laser scanning microscopy analysis, the specimens were transversely sectioned at 4 mm from the apex. The images at ×10 and ×40 were analyzed by Imagetool 3.0 software. Significant differences were not found among the three experimental groups according the dentin‐impregnate area by the sealer (P = 0.68) and between the sealer and root canal perimeter (P = 0.18). However, root canal filling techniques were significantly different when apical sealer areas were compared (P = 0.001). Thermafil group showed smaller sealer areas (8.09%) while cold lateral compaction and gutta‐percha master cone showed similar areas (17.37 and 21.18%, respectively). The dentin‐impregnated area was not dependent on the root canal filling technique. Single master cone, cold lateral condensation and Thermafil techniques presented integrity of the sealer perimeter close to 100% and Thermafil resulted in a significantly thinner sealer layer. Microsc. Res. Tech. 75:1277–1280, 2012. © 2012 Wiley Periodicals, Inc.     

Efficacy of ethylene‐diamine‐tetra‐acetic acid associated with chlorhexidine on intracanal medication removal: A scanning electron microscopy study

The aim of this study was to evaluate the effectiveness of 17% ethylene‐diamine‐tetra‐acetic acid (EDTA) used alone or associated with 2% chlorhexidine gel (CHX) on intracanal medications (ICM) removal. Sixty single‐rooted human teeth with fully formed apex were selected. The cervical and middle thirds of each canal were prepared with Gates Glidden drills and rotary files. The apical third was shaped with hand files. The specimens were randomly divided into two groups depending on the ICM used after instrumentation: calcium hydroxide Ca(OH)₂+CHX or Ca(OH)₂+sterile saline (SS). After seven days, each group was divided into subgroups according to the protocol used for ICM removal: instrumentation and irrigation either with EDTA, CHX+EDTA, or SS (control groups). All specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy. Two calibrated evaluators attributed scores to each specimen. The differences between the protocols for ICM removal were analyzed with Kruskal‐Wallis and Mann‐Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between the score of debris obtained in each root canal third. Remains of Ca(OH)₂ were found in all specimens independently of the protocol and ICM used (P > 0.05). Seventeen percent EDTA showed the best results in removing ICM when used alone (P < 0.05), particularly in those associated with CHX. It was concluded that the chelating agent 17% EDTA significantly improved the removal of ICM when used alone. Furthermore, the type of the vehicle associated with Ca(OH)₂ also plays a role in the ICM removal. Microsc. Res. Tech. 77:735–739, 2014. © 2014 Wiley Periodicals, Inc.     

Residues of different gel formulations on dentinal walls: A SEM/EDS analysis

The aim of this study was to evaluate the presence of residues of sodium hypochlorite gel, chlorhexidine gel, and EDTA gel on dentinal walls after canal preparation through chemical SEM‐ elemental chemical microanalysis (EDS) analysis. Forty‐eight single‐rooted teeth were selected. They had their crowns sectioned and were instrumented with a reciprocating system. The canals were irrigated with 5 mL of saline solution during root canal preparation. After instrumentation, the root canals were irrigated with 3 mL 17% EDTA followed by 1 min of ultrasonic passive activation (3× 20 sec) to remove the smear layer, and then irrigated with 3 mL of saline solution. The specimens were randomized into three groups (n = 12) according to the chemical substance that filled the root canal for 30 min: GI: 5.5% sodium hypochlorite gel; GII: 2% chlorhexidine gel; GIII: 24% EDTA gel; Negative control group: no substance was used. Then, the root canals were irrigated with 6 mL of saline solution followed by 1 min of ultrasonic passive activation (3× 20 sec). After ultrasonic activation, the canals were irrigated with 2 mL saline. The roots were sectioned, and the percentage of each chemical element present in the samples was analyzed through chemical SEM‐EDS microanalysis. All experimental groups showed a significantly higher percentage of chemical elements (Na and/or Cl) than the control group (P < 0.03). This in vitro study has shown that, regardless of chemical solutions used even after the final irrigation protocol, chemical residues of different substances remained attached to the root canal walls. Microsc. Res. Tech. 78:495–499, 2015. © 2015 Wiley Periodicals, Inc.     

Dentinal tubule penetration of endodontic sealers after nonthermal plasma treatment: A confocal laser scanning microscopy study

One of the factors affecting the success of endodontic treatment is to fill the root canal system hermetically. The aim of this in vitro study was to evaluate the effect of nonthermal plasma (NP) on dentinal tubule penetration of root canal sealers using confocal laser scanning microscopy. Forty mandibular premolar teeth were selected and the root canals were prepared with large‐Waveone‐Gold rotary‐files. Specimens were divided into four experimental groups according to sealer and NP treatment (n = 10). G1: AH‐Plus (AH) G2: nonthermal plasma application + AH‐Plus(AH‐P) G3: Endosequence‐BC(BC) G4: nonthermal plasma application + Endosequence‐BC(BC‐P). Cold lateral‐condensation technique was used for the obturation of root canals. The roots were sectioned horizontally and the sections were examined under confocal laser scanning microscopy. The maximum tubule penetration and percentage of penetration values were obtained from the microscopy images and were statistically analyzed with repeated measurements‐ANOVA and the Tukey (HSD) test (p < 0.05). The percentages of dentinal tubule penetration of the groups were not statistically different. The maximum tubule penetration of the AH‐P was statistically lower than that of the BC‐P (p < 0.05). Plasma application had no affect on the percentage of dentinal tubule penetration. Under the conditions of this in vitro Endosequence‐BC sealer showed higher maximum tubule penetration values than AH‐Plus after NP treatment. Percentage of dentinal tubule penetration values of experimental groups was similar.     

Cleaning capacity of octenidine as root canal irrigant: A scanning electron microscopy study

The aim of this study was to assess the cleaning capacity of the octenidine hydrochloride (OCT) used as root canal irrigant by scanning electron microscopy (SEM) analysis. Sixty human unirradicular extracted teeth were randomly distributed in 6 groups (n = 10) according to irrigant solutions which were used during root canal preparation: G1, 0.1% OCT; G2, 2% chlorhexidine (CHX); G3, 2.5% sodium hypochlorite (NaOCl); G4, OCT + 17% ethylenediaminetetraacetic acid (EDTA); G5, 2.5% NaOCl + 17% EDTA and G6, distilled water. All specimens were instrumented with ProTaper system up to F4. Teeth were sectioned and prepared for SEM. The smear layer was evaluated using a 5‐score system and the data were analyzed by Kruskal–Wallis and Dunn (α = 0.05). In all root canal thirds there was no significant difference between OCT, CHX, NaOCl, and water groups (p > .05), and these groups showed higher smear layer values than NaOCl + EDTA and OCT + EDTA groups (p < .05). There was no significant difference between NaOCl + EDTA and OCT + EDTA groups (p > .05). It was concluded that OCT used as a single root canal irrigant presented poor cleaning capacity and could be used in association with a final irrigation with EDTA to obtain smear layer removal.     

Morphological characterization of the oral cavity of the gilthead seabream (Sparus aurata) with emphasis on the teeth‐age adaptation

Gilthead sea bream with different age groups that collected from Seawater fisheries, Ismailia Governorate, Egypt, were examined by gross anatomy and scanning electron microscopy to assess the morphological characteristics of the oral cavity. Teeth patterns showed that the gilthead sea bream is adapted to the feeding pattern according to age development, as it modified from spiny form teeth in young fishes to obelisk‐like teeth and flat dome‐like teeth in growing fishes, with differentiation of teeth into three pairs of canine and conical teeth, that later differentiated to small and large flat teeth. With development, the apical pouch also showed morphological differentiation from curve‐like in small fishes to Y‐letter shape in medium‐sized fishes, which later grow to completely covering the lower jaw in grown adult fishes. Tongue papillae, on the other hand, showed some differentiation being smoother in growing fishes than adult ones. Consistent with development differentiation, the palatine region of young fishes appeared separated from the palate by deep palatine fissure, while that the same palatine region was continuous with the palate with a remnant of palatine fissure as shallow groove was noticed in grown big fishes. Taste buds were characterized in the oral cavity of small and large fishes however in large fishes; the taste buds were more prominent especially at the palate and palatine folds. These and other morphological features of the oral cavity and the feeding habits in small and large gilthead sea bream fishes were recorded. Microsc. Res. Tech. 79:227–236, 2016. © 2016 Wiley Periodicals, Inc.     

Quantitative evaluation of root canal surface roughness after filing with adaptive reciprocating and continuous rotary instruments

Obtaining clean and smooth root canal walls is the ideal clinical outcome of the cleaning and shaping stage in root canal treatment. This study compares the surface roughness of root canal surfaces instrumented with a NiTi filing system with either adaptive reciprocating (AR) or continuous rotation (CR). Root canal cleaning and shaping was carried out on the mesial canals of 24 extracted first molars roots with either AR or CR. Roots were split in half and the surface roughness of their canals was evaluated in 12 three dimensional roughness reconstructions using a scanning electron microscope. Rz (nm) values were calculated in three areas of each reconstruction and analyzed (α = 0.05). Mann‐Whitney tests showed that surface roughness was significantly higher overall in the AR group (Rz = 967 ± 250 nm) compared with the CR group (Rz = 739 ± 239 nm; p = 0.044). The roughness values generally increased from apical towards the coronal third in both groups. A less aggressive finishing file or a continuous rotary system to end the cleaning and shaping stage may be beneficial to reduce roughness of the root canal surface.     

Presence of voids after warm vertical compaction and single‐cone obturation in band‐shaped isthmuses using micro‐computed tomography: A phantom study

The present micro‐computed tomography (micro‐CT) study compared the presence of voids in the band‐shaped isthmuses obturated by warm vertical compaction (WVC) and single‐cone (SC) techniques. Twenty mesial roots from mandibular first molar teeth showing a band‐shaped isthmus were selected and assigned into two groups based on their preoperative anatomical dimensions (n = 10), according to the filling technique: WVC or SC. Post‐filling micro‐CT scanning was performed. The percentage volume of root canal filling materials and voids were calculated and data were analyzed using the Mann–Whitney U test with a significance level of 5 and 95% confidence interval. Mean percentage volumes of filling materials and voids were 86.88 ± 8.53 and 13.11 ± 8.53 for the WVC group, 84.39 ± 8.30 and 15.60 ± 8.30 for the SC group, respectively, with no significant difference between them (p > .05). Neither WVC nor SC produced void‐free root canal fillings in the band‐shaped isthmuses and both techniques resulted in a similar quality of root canal filling.     

Single wavelength micro-endoscopy in non-surgical vascular lesion diagnosis & characterization

Malignant and dysplastic epithelial lesions have often been reported to excite vascular responses by histopathological characterization. Little is reported concerning in vivo real‐time imaging of vascular patterns and flow in health or disease but the development of miniature imaging instrumentation has now allowed such developments. We describe the application of a selective wavelength (540 nm) epi‐illumination Hopkins pattern endoscopic imaging system to image vascular tissues and capillary blood flow in vivo. The contrast mechanism in such imaging was characterized, haemoglobin acting as a chromatic transmission filter despite endoscopy being a non‐invasive and therefore principally reflection mode imaging system. In vivo adrenergic vascular responses, capillary flow rate variations over time and variations in normal capillary architecture around the oral cavity were recorded; demonstrating that simple imaging systems can be used for non‐surgical diagnosis and characterization of vascular lesions, tumours and treatment responses.     

Peracetic acid as a single endodontic irrigant: effects on microhardness,roughness and erosion of root canal dentin

The aim was to assess the effects of 1% peracetic acid (PAA) as a single endodontic irrigant on microhardness, roughness, and erosion of root canal dentin, compared with 2.5% sodium hypochlorite (NaOCl) and with 2.5% NaOCl combined with 17% EDTA. Forty human, single‐rooted tooth hemisections were submitted to Knoop microhardness test, before and after the following irrigation protocols: PAA = 1% PAA; NaOCl = 2.5% NaOCl; NaOCl‐EDTA‐NaOCl = 2.5% NaOCl +17% EDTA +2.5% NaOCl; and SS = saline. Another 40 roots were instrumented, irrigated with the same protocols, and sectioned longitudinally. The roughness analysis was performed on the mesial section using a confocal laser scanning microscope, whereas erosion was analyzed on each third of the distal section, using a scanning electron microscope. The data were analyzed using ANOVA and Tukey post‐tests, and Kruskal‐Wallis and Dunn post‐tests (α = .05). The PAA and NaOCl‐EDTA‐NaOCl groups showed no significant differences (p > .05); both promoted reduction in microhardness and increase in roughness, compared with the NaOCl and SS groups (p < .05). NaOCl‐EDTA‐NaOCl promoted higher erosion in the cervical and middle thirds than the other groups (p < .05); there was no difference among PAA, NaOCl, and SS (p > .05). There was also no difference among the groups regarding the apical third (p > .05). PAA used as a single endodontic irrigant caused reduction in root canal dentin microhardness and increase in roughness in a similar way to NaOCl‐EDTA‐NaOCl; however, PAA caused less erosion than NaOCl‐EDTA‐NaOCl.     

Investigation of mineral content of root canal dentin after the application of various antibiotic paste using energy‐dispersive X‐ray detector

The purpose of this study was to evaluate mineral content of root canal dentin after treatment with different antibiotic pastes including the mixture of metronidazole, ciprofloxacin, doxycycline, cefaclor, amoxicillin, or minocycline. Fifty extracted maxillary canine teeth were randomly divided into five groups (n = 10 teeth for each group). Root canals were prepared Reciproc rotary files. Canals were irrigated using 5 ml 5% NaOCl and 1 ml 15% EDTA. Each tooth in all groups were longitudinally splitted into two pieces as a control and experimental samples. Each experimental group received following antibiotic paste; double antibiotic paste (DAP) and triple antibiotic paste with doxycycline (TAPd), TAP with cefaclor (TAPc), TAP with amoxicillin (TAPa), and TAP with minocycline (TAPm) for 21 days. The Ca, P, Mg, Ca, and K levels, and the Ca/P ratio was analyzed by a scanning electron microscope (SEM) equipped using a Bruker energy‐dispersive X‐Ray (EDX) detector. Data were analyzed with independent samples t‐test, one‐way anova, and Duncan tests. Ca and Ca/P ratio showed a statistically significant increase TAP with amoxicillin and cefaclor (p < .05). DAP, TAPd, and TAPm did not change the mineral levels (p > .05). TAPa and TAPc with increased the Ca level and Ca/P ratio of the root canal dentin which consequently positively influences the revascularization process.     

The effect of a root‐dentin pretreatment technique combining PIPS with MTAD aiming to improve the bond strength of glass fiber post

The aim of this study was to evaluate the combined effect of MTAD and photon‐induced photoacoustic streaming (PIPS) technique on the smear layer removal and the bond strength of glass fiber post. Fifty‐five human mandibular premolars were chosen. After root canal therapy and post space preparation, the teeth were equally divided to five groups according to the methods of root‐dentin pretreatment: G1: distilled water (control); G2: 2.5% NaOCl+17% EDTA; G3: MTAD; G4: PIPS; G5: MTAD+PIPS. One sample was randomly selected from each group, and scanning electron microscope (SEM) was used to observe the microscopic morphology of the coronal, middle and apical level of the root‐dentin. The remaining ten samples from each group were glued to glass fiber posts, and the bond strength was assessed by push‐out test. SEM evaluation showed that the most complete smear layer removal was found in MTAD + PIPS group, especially in coronal third. Push‐out test results exhibited that there was a statistically significant interaction between the experimental groups and root canal third (p < .0005). Significant differences could be found among five groups (p < .05): G5 > G4 > G3 > G2 > G1. G5 had the highest bond strength. In conclusion, post space pretreatments with MTAD or PIPS technique can significantly remove smear layer and improve the bond strength of glass fiber post, and combination of them works best.     

Analysis of adhesive interface in root canals irradiated by Er,Cr:YSGG laser after luting a fiber post

This study evaluated the effect of Er,Cr:YSGG laser on the root canal dentin after luting a fiber post. Twenty‐four bovine teeth roots were prepared using NiTi instruments and filled with Sealer 26 and gutta‐percha. Post spaces were prepared and roots were distributed according to dentin treatment (n = 8): 2.5%NaOCl (group control), Er,Cr:YSGG laser (1.5 W, 20 Hz, 20 s) (group test 1) or 2.5%NaOCl + Er,Cr:YSGG laser (group test 2). Fiber posts were luted using adhesive cement (Rely X U200, 3M) and roots were prepared to confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM). The morphology of interface, thickness of cement, and the gaps and tags were analyzed. Non‐parametrical data for thickness of cement were submitted to Friedman and Kruskall–Wallis tests (α = 0.05) and parametrical data for gaps to ANOVA (α = 0.05). CLSM of the cement thickness and gaps revealed no significant difference in surface treatment (NaOCl, Er,Cr:YSGG laser and NaOCl + Er,Cr:YSGG laser) (p > .05) and canal thirds (cervical, middle, and apical) (p > 0.05). SEM showed tags and a residual layer of cement adhered to dentin, mainly in laser‐irradiated specimens. The pretreatment of root canal with Er,Cr:YSGG laser previously to luting the fiber post with a self‐adhesive cement did not influence the cement thickness and gaps but affected the dentin interaction.     

Effect of sodium hypochlorite on the cyclic fatigue resistance: A scanning electron microscopy evaluation

The main purpose of this study was to compare the cyclic fatigue resistances of the three different nickel–titanium files in 2.5% sodium hypochlorite solution and distilled water at physiologic intracanal temperature (35°C). Three NiTi files such as One Curve (OC) (Micro‐Mega, Besancon, France), OneShape (OS) (Micro‐Mega), and Protaper Next (PTN) X2 (Dentsply Sirona, Ballaigues, Switzerland) were tested for cyclic fatigue resistance inside artificial stainless steel canal block with curvature 60° and 5 mm radius. The block was fixed inside a hot water bath of distilled water or 2.5% sodium hypochlorite and the temperature was set at 35 ± 1°C. The number of cycles to fracture data were recorded and all the fracture surfaces of files were evaluated by using scanning electron microscopy. The number of cyclic to fracture data were analyzed statistically via Kruskal–Wallis and Mann–Whitney U tests. OC showed the highest cyclic fatigue resistance at distilled water while PTN X2 showed the lowest cyclic fatigue resistance at 2.5% sodium hypochlorite. When cycling fatigue test medium were changed from distilled water to sodium hypochlorite solution, the resistance of the files to cyclic fatigue were decreased. SEM analysis confirmed that all scanned samples were fractured due to cyclic fatigue. The OC rotary instruments have more cyclic resistance than OS and PTN X2. The sodium hypochlorite solution reduces the resistance of the rotary instruments.