Shaping Procedure Research Articles

Multi-objective optimisation of tube hydroforming process on IF steel using Taguchi-based principal component analysis

Tube hydroforming is one of the eccentric metal shaping procedures, especially utilised as a part of the automotive industry. This process has accentuated much consideration inferable from its diversified applications. To emphasise, aerospace and automotive industries depend much upon this procedure. Earlier most of the researchers worked on the material characterisation and the process parametric impacts of tube hydroforming process. However, very few have attempted on the Multi-objective optimisation of the critical process parameters. In this work, commercial finite element code PAM-STAMP 2G is utilised to do the simulations in view of L27 orthogonal array. Hence a multi-objective optimisation was studied that simultaneously maximises the bulge ratio and minimises the thinning ratio by Taguchi-based principal component analysis (PCA), which is novelty of this work. The present work aims at exploring the impact of geometrical, process and material parameters on aforementioned responses using analysis of variance (ANOVA).

Selenium intracanal dressing: effects on the periapical immune response.

To evaluate the selenium (Se) behavior when used as an endodontic dressing in teeth with pulp necrosis. Additionally, its effects was also compared with the calcium hydroxide (C.H.), which is used globally as a root canal dressing, and the combination of the C.H. with Se (C.H. + Se). The sample consisted of 60 patients requiring endodontic treatment who were divided into groups, i.e., without intracanal medication (empty) and with medications as follows: selenium (Se), calcium hydroxide (C.H.), and calcium hydroxide + selenium (C.H. + Se) (n = 15). After the coronary opening, three absorbent paper points were placed in the RCS and maintained for 2min for microbial evaluation. Following the cleaning and shaping procedures, new paper points were introduced into the root canal system, passing passively through the root apex (2mm) into the periapical tissues for 2min, for immune evaluation. The collections were performed again 15days later. Real-time PCR quantified the expression of the prokaryotic 16S ribosomal RNA. The 16S mRNA was evaluated before the cleaning and shaping procedures and 15days later in the groups treated with or without medication. A significant reduction in the microbial load was observed only in the groups that received endodontic dressing (p < 0.05). The cytokines IFN-γ, TNF-α, IL-1α, IL-17A, IL-10, IL-6 and MCP-1, were also quantified by real-time PCR. There was an increase in the gene expression level of the cytokines (T15) TNF-α and IL-10 in the C.H. group compared to the other groups (p < 0.05). The IFN-γ mRNA expression was reduced in the groups treated with the medications (Se, C.H., and C.H. + Se). The findings of the present study indicate that in the case of treatment over multiple sessions, the use of root canal dressing is essential to avoid the root canal system (RCS) microbial recolonization. Selenium potentiated the effects of calcium hydroxide inducing an anti-inflammatory response in periapical tissues. Se is a mineral essential for the formation of the amino acid selenocysteine, which is directly involved in the maintenance of the immune response. Selenium has been widely used in the medical field in the treatment of cancer, as an activator of bone metabolism, and as a stimulator of the immune system. In this study, it was shown that the incorporation of Se, whether as intracanal medication alone or in conjunction with other medications, may potentiate periapical tissue repair after RCS cleaning and shaping procedures.

Landscape genetics of sheep in Brazil using SNP markers

The aim of this study was to explore spatial patterns of genetic structure in sheep breeds sampled in Brazil using Single Nucleotide Polymorphisms (SNPs) in order to evaluate whether or not the genetic and geographic distances are interrelated in this species. Samples genotyped using the 50KSheepSNPChip (Illumina) included 215 animals from eight different sheep breeds. All collection sites were georeferenced and data analyzed to determine geographic patterns from genetic data. To evaluate the correlation between genetic and geographic distances Mantel tests, Allelic Aggregation Index Analyses (AAIA), and spatial autocorrelation were performed. Genetic Landscape Shape procedure and Monmonier’s Algorithm were used to generate graphical visualization of the genetic distances across the landscape. The observed correlation observed between genetic and geographical distances was 0.552 (P < 0.00099). Observed AAIA results (Rave = 0.16, P < 0.001) indicated a non-random distribution of genotypes across the landscape. High genetic differentiation was observed in the Southern regions of Brazil, separating wool and hair sheep. Low genetic distances were observed between flocks and breeds from north and center-west regions, and may be the result of unrecorded introgressions resulting from past unknown crossbreeding events. Observed Spatial Autocorrelation Analyses results indicate a minimum distance of 400 km should be used between collection sites to maximize genetic variability in future germplasm samplings for conservation of genetic resources.

A Comparison of Fixed-Time Food Schedules and Shaping Involving a Clicker for Halter Behavior in a Petting Zoo Goat

This study examined two procedures for establishing halter behavior (i.e., acceptance of wearing and being led via a halter) and decreasing undesired behavior in three petting zoo goats: a fixed-time 15-s (FT-15-s) schedule and shaping involving a clicker. The FT schedule was successful in training initial approximations, but over a longer period for the one goat presented in this article. The shaping procedure rapidly advanced the final approximations to the target behavior and resulted in a large reduction in undesired responses once the target response was reached. The procedures were also equally effective at reaching the target response and greatly reducing undesired responses for the other two goats not presented in this article. This study is one example of an effective way to experimentally examine shaping procedures, as well as promote the use of force-free halter training and behavior in goats.

Morphologic Changes of Apical Foramen and Microcrack Formation after Foraminal Enlargement: A Scanning Electron Microscopic and Micro–computed Tomographic Analysis

IntroductionThe aim of the present study was to evaluate the morphologic changes on the apical foramen and the formation of dentinal microcracks after foraminal enlargement in straight and curved root canals using scanning electron microscopic (SEM) and micro–computed tomographic (micro-CT) analyses. MethodsSixty teeth were selected and divided into 2 experimental groups: GI (incisors/straight group, n = 30) and GM (molars/curved group, n = 30). Each group was divided into 2 subgroups (n = 15) according to the analysis performed: SEM or micro-CT analysis. The incisors and mesiobuccal canal of molars were instrumented with Reciproc Blue R25 instruments (VDW, Munich, Germany) using standardized shaping procedures in the apical foramen and 1 mm beyond. The occurrence of foraminal deformation was analyzed by scanning electron microscopy. The z test was used for statistical analysis (P < .05). Micro-CT imaging was used to observe the presence of microcracks in the root apical third. Afterward, pre- and postoperative cross-sectional images were screened to identify the presence of dentinal defects. ResultsThe curvature of the canal did not influence the occurrence of foraminal deformation either for instrumentation in the foramen or for instrumentation beyond the foramen (P > .05). It was also observed that the increase in the working length did not influence the appearance of new deformations in the GI/SEM and GM-SEM groups (P > .05). Qualitative micro-CT analysis showed the presence of dentinal defects in 0.8% (112) and 1.5% (208) of the cross sections of incisors and molars, respectively, from a total of 13,987 slices. All dentinal defects identified in the analysis of any postoperative scans were already present in the corresponding preoperative images. Therefore, no new microcracks were observed after root canal preparation. ConclusionsThe preparation of straight and moderately curved root canals with Reciproc Blue, regardless of the working length, did not influence the occurrence of apical foramen deformations and did not cause the formation of dentinal microcracks.

Immunological profile of periapical endodontic infection in patients undergoing haematopoietic transplantation.

To evaluate the mRNA expression levels of cytokines interferon-γ, tumour necrosis factor-α, interleukin IL-1β, IL-10, and the chemokine CCL2/MCP-1, CCL4, and CXCR4 in the periapical interstitial fluid from root canal infections before and after bacterial load reduction in patients undergoing haematopoietic stem cell transplantation (HSCT). The case group was composed of 10 patients undergoing HSCT, and our control group included 10 healthy patients. Clinical samples were taken from teeth with pulp necrosis. Three paper points were placed in the RCS and maintained for 2min for microbial evaluation before cleaning and shaping procedures. After cleaning and drying the canal, three paper points were introduced into the root canal, passing passively through the root apex (2mm) into the periapical tissues for 1min. Samples were collected immediately after root canal cleaning and 7days later (restrained root canal bacterial load) to characterize gene expression using real-time PCR. The results showed significantly reduction in the microbial load on day 7. An increased expression level of TNF-α and IFN-γ on day 7 in control and case groups was observed (p < 0.05). The mRNA levels of IL-1β and IL-10 in the pre-HSCT group increased in the samples from day 7 (p < 0.05). The chemokine CCL-2/MCP-1 was not detected in pre-HSCT group. Chemokine receptor CXCR4 levels increased in samples obtained from the day 7 in the control group (p < 0.05). Individuals undergoing HSTC presented similar cytokine and chemokine mRNA expression compared with healthy individuals. However, it was observed the total absence of mRNA MCP-1/CCL2 expression in those individuals undergoing HSCT. Patients undergoing HSCT are at higher risk of infection. No study has analysed the periapical immune responses to root canal infections in HSCT individuals.

Training Petting Zoo Sheep to Act Like Petting Zoo Sheep: An Empirical Evaluation of Response-Independent Schedules and Shaping with Negative Reinforcement.

Simple SummaryThe present study examines the use of response-independent food schedules (food delivered independent of what an animal is doing) and negative reinforcement in the form of a trainer removing themselves from the presence of an animal to effectively train approach and contact behaviors in petting zoo sheep. All sheep had previously been reported to avoid/escape the presence of zoo staff and caretakers, as well as refuse to eat in the presence of any persons. In Experiment 1, we were able to effectively use response-independent schedules to produce both approach and contact behaviors in a Hampshire sheep. In Experiment 2, a Jacob sheep was trained for approach/contact via a shaping procedure that initially rewarded approach behaviors by removing the presence of the trainer (negative reinforcement), and was later switched to rewarding responses directly with food (positive reinforcement) once the sheep began to regularly eat in the trainer’s presence. The results are discussed with respect to how both procedures are effective in examining the applied approach/avoidance behaviors with zoo animals, as well as the greater ethical considerations involved in using negative vs. positive reinforcement to train animals.Shaping through differential reinforcement of successive approximations to a target response has been a cornerstone procedure for the training of novel behavior. However, much of how it has traditionally been implemented occurs through informal observation, rather than any direct, systematic measurement. In the present study, we examine the use of response-independent food schedules and shaping for increasing approach and contact behaviors in petting zoo sheep. In Experiment 1, a fixed-time (FT) 15 s food schedule was used to effectively increase approach and contact behaviors in one sheep. In Experiment 2, negative reinforcement in the form of removal of the presence of a trainer was made contingent on the successful completion of approximations within a shaping procedure and later switched to food rewards. A changing-criterion design was used to empirically examine the effects of the shaping procedure during each step of the program. The result is one of the first studies to demonstrate the utility of using negative reinforcement within a shaping procedure to successfully intervene on approach/avoidance behaviors in an applied animal setting.

Comparison of Antibacterial Effect and Smear Layer Removal of Herbal versus Traditional Irrigants - An in vitro Study

Background: Elimination of endodontic pathogens through appropriate cleaning and shaping procedures along with strict isolation protocols is of great significance for disinfecting this complex anatomy of the root canal configuration. Persistent periradicular lesions are usually associated with Enterococcus faecalis. Various compounds are being utilized as irrigants throughout the cleaning shaping procedures to accomplish the favorable level of disinfection. Aim: the current study aim to compare the anti-microbial efficiency of Salvadora Persica (Miswak-Siwak) and Chitosan in comparison with Sodium Hypochlorite (NaOCl). Also comparing their ability to eradicate the smear layer. Materials and Methods: Seventy-five extracted human single rooted teeth were cut at the cemento-enamel junction (CEJ). The roots were instrumented by k-files till size 25. These teeth were sterilized and then contaminated by Enterococcus Faecalis in brain heart infusion for 3 weeks. The samples will divide into 4 groups (S.Persica, Chitosan, NaOCl and normal saline). The bacterial count was calculated using colony forming unit (CFU). Then, the roots were split longitudinally and examined by SEM for evaluation of smear layer removal in coronal, middle and apical thirds. Results: Regarding antibacterial effect, NaOCl showed the least mean values, however saline showed the highest, followed by S. Persica and Chitosan. Regarding smear layer removal, S.Persica showed the least values. NaOCl and positive control showed the highest, followed by Chitosan. Conclusion: The use of herbal alternatives as root canal irrigating solutions might prove to be advantageous considering several unfavorable properties of NaOCl. Key words: Antibacterial efficacy, Chitosan, Enterococcus faecalis, Root canal irrigation, S.Persica, NaOCl.

One visit endodontic on asymtomatic mummificated mandibular molar

Background. The main goal of root canal treatment is the prevention or treatment of apical periodontitis, which leads to the preservation of natural teeth. Traditionally, root canal treatment is carried out in a number of visits, using extra disinfecting agents in addition to irrigant used during cleaning and shaping procedures that primarily aim to reduce or eliminate microorganisms and their byproducts. from the root canal system before it is obtained. Recent advances in Endodontic technology, attracting dental experts and endodontists to perform root canal treatment in one visit. Numerous studies evaluate the effectiveness of single-versus multiple-appointment root canal treatment have been published, which reported no significant differences in effectiveness (healing rates) between these two treatment regimens.Purpose : preservation of the integrity of the molar teeth that have symptomatic complaints by taking proper care with a short visit time. Caset: A 21-year-old woman presents with concern in her lower left tooth, the patient tells that the tooth had been treated before at the dentist when she was a child. On clinical examination there is a composite restoration in occlusal tooth # 36, non vital teeth. On periapical radiology there are radiopaque on pulp chamber and a diffuse radiolucent area in the apical area of tooth # 36, then the diagnosis then determined Previously initiated therapy with asymptomatic apical periodontitis. Case Management : Tooth # 36 treated with one visit root canal treatment, Treatment is continued with fiber post installation and crown, patients no longer complain of pain after treatment. Teeth function normally again. Conclusion: One visit root canal treatment can successfully eliminate patient complaints and restore tooth function.

Precision of Dynamic Navigation to Perform Endodontic Ultraconservative Access Cavities: A Preliminary In Vitro Analysis

IntroductionUltraconservative access cavities (UCACs) have been proposed to reduce crown weakening, but there is no consensus about their design and size and about their advantages and disadvantages, which are also related to how differently they are performed. The purpose of the present study was to evaluate the possible use of a novel Dynamic Navigation System (DNS) in planning and executing UCACs and its precision in vitro, compared with a manual approach (MA) without any guide. MethodsTwenty radiopaque, artificial teeth replicas were randomly divided into 2 identical groups and scanned using cone-beam computed tomography. In the first group (MA) MB1 canal orifice was reached, starting from the central part of the molar occlusal surface, using a micro endodontic bur. In the second group, DNS allowed to plan and execute a more direct, straight-line truss access. After cavity preparation, teeth were scanned again, and cone-beam computed tomography images were compared. Data were statistically analyzed with analysis of variance test. ResultsSignificant differences (P < .05) were found in the tested parameters between the 2 groups. The DNS group was significantly more precise, showing smaller mean values in the angulation (4.8°) and in the maximum distance from the ideal position (0.34 mm), when compared with MA group (mean values, 21.2° and 0.88 mm, respectively). ConclusionsHence, we may conclude that the use of DNS increased the benefits of UCACs by minimizing the potential risk of iatrogenic weakening of critical portions of the crown and reducing negative influences to shaping procedures.

Spectral and spatial shaping of laser-driven proton beams using a pulsed high-field magnet beamline

Intense laser-driven proton pulses, inherently broadband and highly divergent, pose a challenge to established beamline concepts on the path to application-adapted irradiation field formation, particularly for 3D. Here we experimentally show the successful implementation of a highly efficient (50% transmission) and tuneable dual pulsed solenoid setup to generate a homogeneous (laterally and in depth) volumetric dose distribution (cylindrical volume of 5 mm diameter and depth) at a single pulse dose of 0.7 Gy via multi-energy slice selection from the broad input spectrum. The experiments were conducted at the Petawatt beam of the Dresden Laser Acceleration Source Draco and were aided by a predictive simulation model verified by proton transport studies. With the characterised beamline we investigated manipulation and matching of lateral and depth dose profiles to various desired applications and targets. Using an adapted dose profile, we performed a first proof-of-technical-concept laser-driven proton irradiation of volumetric in-vitro tumour tissue (SAS spheroids) to demonstrate concurrent operation of laser accelerator, beam shaping, dosimetry and irradiation procedure of volumetric biological samples.

Influence of Pore-Size Distribution on the Resistance of Clay Brick to Freeze–Thaw Cycles

This study examines the influence of raw material characteristics, methods of shaping and of parameters of firing process of clay bricks, on pore-size distribution and on resistance to freeze–thaw cycles (with particular emphasis on the retention time of the specimens at the maximum achieved temperature). Pore-size distribution was measured by mercury-intrusion porosimetry, while the resistance to freeze–thaw cycles was assessed by exposing the bricks to freeze–thaw cycles (HRN B.D8.011 standard) monitoring the appearance of surface changes, decrease of compressive strength as well as the Maage factor. A correlation was set up between the Maage factor and the ratio of the compressive strength before and after freezing as a quantitative indicator of bricks resistance to frost. By using this correlation for all the examined bricks, regardless of their raw material and shaping procedure, a low coefficient of correlation (R2 = 0.26) was obtained. When processed separately, machine-made bricks had a significantly higher correlation coefficient value (R2 = 0.60) than the hand-made bricks (R2 = 0.28).

An Examination of Shaping with an African Crested Porcupine (Hystrix cristata)

ABSTRACT Shaping through differential reinforcement of successive approximations to a target response has been a cornerstone procedure for the training of novel behavior. However, much of how it has traditionally been implemented occurs through informal observation, rather than any direct, systematic measurement. In the following study, an African crested porcupine (Hystrix cristata) was trained to touch and hold to a target for 30 s. A changing-criterion design with one reversal was used to assess the success of the shaping procedure and empirically examine the effects of the shaping procedure during each step of the program. The study allowed for the examination of each approximation across all other approximations, as well as across aberrant (e.g., trial-terminating) responses. The design and procedure allow for a simple and systematic way to examine the effects and success of shaping procedures across a variety of settings, species, and purposes.

Ex-Vivo Comparison of Torsional Stress on Nickel-Titanium Instruments Activated by Continuous Rotation or Adaptive Motion.

This study aimed to evaluate the effect of adaptive motion applied to conventional nickel-titanium (NiTi) rotary instruments on torsional stress generation during shaping procedure. One hundred and twenty mesio-buccal canals of molars were randomly assigned to two groups according to the kinetics; adaptive motion (AD) and continuous rotation (CR). Each group was divided into four subgroups (n = 15) according to the NiTi instrument systems: HyFlex EDM, One Curve, Twisted File Adaptive, and ProTaper Next. A glide path was established with PathFile #1, for each file group being used with either of the kinetic movements. During the instrumentation with the designated motion and file system, the generated torque was measured via the control unit and acquisition module. Based on the acquired data, the maximum and total torque were calculated. The data were statistically analyzed using Kruskal–Wallis and Mann–Whitney tests at a significance level of 95%. The maximum and total torque generated by all instruments were significantly reduced by the adaptive motion (p < 0.05). In the CR group, HyFlex EDM generated the highest maximum and total stress. In the AD group, HyFlex EDM showed the highest maximum torsional stress, and One Curve showed the highest total torsional stress (p < 0.05). The TF Adaptive instrument with adaptive movement produced the lowest maximum and total torsional stress (p < 0.05). Under the conditions of this study, the use of adaptive motion would be useful to reduce the torsional stress of instrument and root dentin. The reduction of torsional stress through adaptive motion may enhance the durability of instruments and reduce the potential risk of dentinal cracks.

The Potential Use of Waste Cement as a Filler in Polymer Composites

This study explores the potential to use waste cement particles from ready-mixed concrete industry as a low cost filler in polypropylene. Its effects on mechanical and morphological properties were investigated in comparison with commercial cement and calcium carbonate. Mixing and shaping procedures of the polymer composites specimen were conducted by two-roll mill and injection molding, respectively. Next, the effect of filler loading (0, 10, 20, 30, 40, and 50 phr) and filler type on the mechanical and morphological properties of the polymer composites were studied. The results show that when filler loadings increased, the young’s modulus, flexural modulus, impact strength, and hardness of the polymer composites also increased accordingly, while the tensile strength and flexural strength decreased. Moreover, the results show that the waste cement had a greater effect on the enhanced mechanical properties compared to commercial cement and calcium carbonate. Furthermore, the polymer composites’ morphology was studied using scanning electron microscopy. A microstructure analysis was performed to verify and provide a better assessment of the performance properties of the polymer composites.

Strategy for identification of HCP structure materials: study of Ti–6Al–4V under tensile and compressive load conditions

This work proposes a new constitutive model that takes into account the asymmetry of Ti–6Al–4V, its microstructural state and its pronounced anisotropy in order to improve the use of this titanium alloy in biomechanics and aeronautics in particular. The choice of the stress directions and their effect on shaping procedures in light of accounting the effect of heat treatment on the behavior of Ti–6Al–4V, hardness and microstructural defects is important. The fracture surfaces of a material specimen subjected to traction/compression is examined using scanning electron microscope. An appropriate choice of the model is necessary through experimental validation. The use of this alloy in the biomechanical field brings into consideration several factors such as different solicitations and uniaxial loads, and tension-compression asymmetry...as well as in the aeronautical field other factors such as material strength and ductility in shaping under certain heat treatment are considered.

Clinical endodontic procedures modulate periapical cytokine and chemokine gene expressions

To identify the gene expression of the cytokines IL-9, TNF-α, IL-1, INF-γ, IL-17A, and IL-10 and the chemokines CCL-2/MCP-1 and CCR-6 in the periapical fluid of human root canal infections. Twenty samples were collected immediately and 7days after the cleaning and shaping procedures (after reducing the intracanal microbial load) in an attempt to characterize the expression of these genes. The endogenous expression levels of cytokines and chemokines were analyzed by real-time polymerase chain reaction. The Shapiro-Wilk and the Wilcoxon tests analyzed data. Significantly higher levels of the IL-9, INF-γ, TNF-α, IL-1, and IL-10 markers on day 7 were observed compared with day 0 (p < 0.05). However, IL-17A and the chemokines CCL-2/MCP-1 and CCR-6 did not show a significant difference in mRNA expression when comparing both timepoints (p > 0.05). The clinical variation of the periapical immune status after endodontic therapy suggests that the cytokine and chemokine-mediated pro-inflammatory response appears to be modulated in an IL-10/IL-9-dependent manner. Few studies have investigated the role of Th9 cells in periapical lesions. IL-9 presents exciting plasticity, performing immunosuppressive actions, and it is also capable of changing their phenotype in the presence of IL-17. Hence, it is relevant to investigate its role in the context of the known mediators involved the periapical immune process.

Response shaping to improve food acceptance for children with autism: Effects of small and large food sets

BackgroundFood selectivity, characterized by food refusal, limited food repertoire, or preference for certain types of foods, is common among children with ASD. MethodIn this study, researchers examined the effects of a response shaping procedure using a large rotating food set and a small constant food set on food acceptance for two boys with ASD. The small set consisted of three foods that were presented during every session; the large set consisted of 15 foods, of which three were presented during each session, in randomly ordered sets. Researchers measured the percentage of correct behaviors and the cumulative number of foods with which participants interacted. Two concurrently operating multiple baseline across behaviors designs were used to assess whether the shaping procedure resulted in increased correct responding compared to baseline conditions, and whether the intervention was differentially effective with large versus small food sets. ResultsThe procedures were similar in efficiency for one participant, although he ate many more foods in the large set condition. For the other participant, shaping was successful at increasing some acceptance behaviors (e.g., putting food in his mouth) but only the small set resulted in eating a new food. ConclusionsPractitioners should consider use of less restrictive or intrusive interventions to promote food acceptance and the use of larger sets of foods, modified to include fewer foods in the case of poor response to intervention.

Effect of final irrigant on depth of tubular penetration of resin-based root canal sealer and bioactive sealers using confocal laser scanning microscope

Background: Deep dentin tubular penetration of the sealer provides a three dimensional sealing of root canal space Aim: To evaluate the effect of final irrigant on depth of tubular penetration of resin based root canal sealer and bioactive sealers using Confocal Laser Scanning Microscope (CLSM) Materials and Method: Ninety- six freshly extracted human mandibular first premolar teeth were decoronated at 15 mm from the apex. Cleaning and shaping procedure was accomplished using Hyflex CM rotary files till F3. The sample were divided into three groups(n=32) according to final irrgant used : Group A (17 % EDTA), Group B (QMix 2 in 1), Group C (Distilled water). The final irrigation in each respective group was performed with EndoVac system. The samples were further subdivided into 4 subgroups (n=8) according to the type of sealer used for obturation with 6% guttapercha cones - Subgroup I (AH Plus), Subgroup II (Gutta Flow Bioseal), Subgroup III ( Endosequence BC ), Subgroup IV (EndoSeal MTA). Two mm horizontal sections were obtained at 2 mm (apical sections), 5 mm (middle sections) and 7 mm (coronal sections) from the root apex using CLSM to evaluate the maximum depth and percentage of sealer penetration into the dentinal tubules by using Kruskal-Wallis test for overall analysis and a series of Mann-Whitney U tests for pairwise comparison. Result: Endosequence BC showed maximum depth of penetration and penetrated percentage perimeter, while Gutta Flow Bioseal showed least values. Q Mix 2 in 1 showed better penetration values than EDTA and distilled water. Conclusion: Irrigants, nature of sealer and level of root canal affected sealer penetratio.

Possible Complications of Endodontic Treatments

Endodontic treatments tend to have very high successful rates in spite of the fact that they are quite an invasive, difficult procedure, especially in complex anatomies. Some complications can arise during or after a root canal procedure due to poor understanding of the anatomy and iatrogenic errors mainly during instrumentation. While some of these problems can be anticipated, many can never really be predicted.1-3 As a consequence, retreatment has become a well-defined field of knowledge and expertise in endodontics, since most complications can be solved with proper surgical or nonsurgical retreatments.4 Reinfection or persistent infections: Root canal treatment can fail due to a persistent bacterial infections or reinfections. These include inadequate shaping, cleaning, and obturation procedures, poor restorations, and exposure through a fracture. The remedies are dependent on the primary cause of the reinfection and the affected parts. Persistent infection is the major cause of short-term endodontic failures.5.