CBCT Assessment of Root Dentine Removal by Gates-Glidden Drills and Two Engine-Driven Root Preparation Systems

Introduction: The aim of this study was to compare the dentine removing efficacy of Gates-Glidden drills with hand files, ProTaper and OneShape single-instrument system using cone-beam computed tomography (CBCT). Methods and Materials: A total of 39 extracted bifurcated maxillary first premolars were divided into 3 groups (n=13) and were prepared using either Gates-Glidden drills and hand instruments, ProTaper and OneShape systems. Pre- and post-instrumentation CBCT images were obtained. The dentin thickness of canals was measured at furcation, and 1 and 2 mm from the furcation area in buccal, palatal, mesial and distal walls. Data were analyzed using one-way ANOVA test. Tukey’s post hoc tests were used for two-by-two comparisons. Results: Gates-Glidden drills with hand files removed significantly more (P<0.001) dentine than the engine-driven systems in all canal walls (buccal, palatal, mesial and distal). There were no significant differences between OneShape and ProTaper rotary systems (P>0.05). Conclusion: The total cervical dentine removal during canal instrumentation was significantly less with engine-driven file systems compared to Gates-Glidden drills. There were no significant differences between residual dentine thicknesses left between the various canal walls.Keywords: Cone-Beam Computed Tomography; Maxillary First Premolar; Root Canal Preparation; Root Thicknes

The Effect of Task Type and Word Type on Vocabulary Learning: A Comparison Based on Involvement Load Hypothesis and Technique Feature Analysis

This study aimed to investigate the effect of task type (i.e., sentence fill-in/sentence writing) and word type (i.e., real/ pseudo) on initial learning and retention of 10 word meanings, taking the predictions of Involvement Load Hypothesis (ILH) and Technique Feature Analysis (TFA) into account. Participants were 59 intermediate-level EFL learners from eight intact classes. Each intact class was randomly assigned to one of the four learning conditions: 1) sentence fill-in with real words, 2) sentence writing with real words, 3) sentence fill-in with pseudowords, and 4) sentence writing with pseudowords. Initial learning was measured by administering a meaning recall test immediately after the tasks and medium-term retention was measured by administering the same test with rearranged items one week after the tasks phase. The results of a mixed between-within subjects ANOVA did not show any significant interaction effect between test time and learning condition. Furthermore, the main effect for learning condition was not statistically significant but there was a significant main effect for test time, suggesting that participants’ scores dropped significantly from the immediate posttest to the delayed posttest. The findings of two independent-samples t-tests failed to show any significant difference between the immediate and delayed posttest scores of the participants who received either sentence fill-in or sentence writing tasks. However, some tentative findings demonstrated that those participants who were assigned to the sentence writing task achieved higher scores on the posttests. This finding indicates that TFA has probably more predictive power than ILH and it also provides some evidence in favor of the heavier weight of the evaluation component of the ILH when compared to its search component

Accuracy of Conventional and Digital Radiography in Detecting External Root Resorption

Introduction: External root resorption (ERR) is associated with physiological and pathological dissolution of mineralized tissues by clastic cells and radiography is one of the most important methods in its diagnosis. The aim of this experimental study was to evaluate the accuracy of conventional intraoral radiography (CR) in comparison with digital radiographic techniques, i.e. charge-coupled device (CCD) and photo-stimulable phosphor (PSP) sensors, in detection of ERR. Methods and Materials: This study was performed on 80 extracted human mandibular premolars. After taking separate initial periapical radiographs with CR technique, CCD and PSP sensors, the artificial defects resembling ERR with variable sizes were created in apical half of the mesial, distal and buccal surfaces of the teeth. Ten teeth were used as control samples without any resorption. The radiographs were then repeated with 2 different exposure times and the images were observed by 3 observers. Data were analyzed using SPSS version 17 and chi-squared and Cohen’s Kappa tests with 95% confidence interval (CI=95%). Result: The CCD had the highest percentage of correct assessment compared to the CR and PSP sensors, although the difference was not significant (P=0.39). It was shown that the higher dosage of radiation increases the accuracy of diagnosis; however, it was only significant for CCD sensor (P=0.02). Also, the accuracy of diagnosis increased with the increase in the size of lesion (P=0.001). Conclusion: Statistically significant difference was not observed for accurate detection of ERR by conventional and digital radiographic techniques

Coronal Discoloration Induced by Calcium-Enriched Mixture, Mineral Trioxide Aggregate and Calcium Hydroxide: A Spectrophotometric Analysis

Introduction: The aim of this study was to compare the discoloration potential of calcium-enriched mixture (CEM) cement, white mineral trioxide aggregate (WMTA) and calcium hydroxide (CH), after placement in pulp chamber. Methods and Materials: Access cavities were prepared in 40 intact maxillary central incisors. Then, a 2×2 mm box was prepared on the middle third of the inner surface on the buccal wall of the access cavity. The specimens were randomly assigned into four groups; the boxes in the control group were left empty, in groups 1 to 3, the boxes were filled with CH, WMTA and CEM cement, respectively. The access cavities and the apical openings were sealed using resin modified glass ionomer (RMGI). The color measurement was performed with a spectrophotometer at the following intervals: before (T0), immediately after placement of the filling material (T1), one week (T2), 1 month (T3), 3 months (T4) and 5 months (T5) after filling of the box and finally immediately after removing the material from the boxes (T6). Color change (ΔE) values were calculated using the sample Kolmogorov-Smirnov test to determine the normal distribution of data, followed by ANOVA, repeated measured ANOVA and post-hoc Tukey’s tests. Results: All materials led to clinically perceptible crown discoloration after 1 week. The highest ΔE value belonged to WMTA group. Discoloration induced by CEM cement was not significantly different from CH or the control group (P>0.05). Conclusion: CEM cement may be the material of choice in the esthetic region, specifically pertaining to its lower color changing potential compared to WMTA.Keywords: Calcium-Enriched Mixture Cement; Mineral Trioxide Aggregate; Spectrophotometry; Tooth Discoloratio

Simulation

Background & Objective: Simulation is an educational technique which through providing whole or part of a clinical experience helps students to learn without being afraid of either their personal weaknesses or hurting the patient during interaction. Manipulation of medical education is widely being spread all over the world and this can be due to various factors such as technological improvements, ethical issues relating to practicing clinical skills, crowdedness of clinical environments for educational purposes, illness severity in most patients, drop in the length of patient’s stay in the hospitals, shortage of specialized staff in hospitals to facilitate educational process and so on. Methods: The current study has reviewed existing books, library references, papers and essays available in different scientific databases using keywords of “simulation”, “medical education” and “clinical skills”. Results: Simulation offers several advantages including increase in patient’s safety, reinforcement of interactive learning and student-centered, improvement in problem-solving abilities and critical thinking skills, and self-paced learning. Despite all the above-mentioned benefits, the point is that due to the high costs of simulation equipment as well as improper cost management policies particularly in educational centers, several studies should be run to analyze outcomes of manipulation of different simulators on students’ learning and then based on the efficiency of the simulators, the proper ones be used for educational purposes in clinical environments. Keywords Simulation Medical education Clinical skill

Comparing Pulsed-dye Laser with Cryotherapy in the Treatment of Common Warts

INTRODUCTION: No modality has been identified as the treatment of chice for treating common warts. Cryothearpy and pulsed-dye laser (PDL) are among common modalities for treating these lesions. The aim of this study was to compare pulsed dye laser with cryotherapy in terms of efficacy and complications.METHODS: Of a total of 46 patients enrolled in this study, 7 patients withdrew the study, 20 patients underwent cryotherapy and 19 patients underwent PDL. Patients underwent a maximum of 4 therapeutic sessions at 3-week intervals in both groups. They were assessed for the remission rate (complete and partial),side effects and recurrence rate in each session and 1 month after termination of the treatments.RESULTS: At the end of the study complete remission was achieved in 37.8% of patients in cryotherapy group and in 52.3% of patients in PDL group. This difference wasn’t statistically significant (P=0.229), though after first and second sessions of treatment complete and excellent partial remission occurred more in PDL group with significant difference (P=0.007 and P=0.021). Pain and bulla formation occurred statistically higher in cryotherapy group (P=0.002 and P=0.001). Other complications were rare in both groups.CONCLUSION: In terms of efficacy, we couldn’t demonstrate the superiority of pulseddye laser therapy to cryotherapy in treating common warts. Both methods were safe for long-term complications but PDL was much safer for short-term complications

Influence of Pt on structural and morphologycal properties of La2O3/SnO2 thick film

In this study, the effect of Lanthanum oxide doped tin oxide (La2O3/SnO2) surface modification by Pt synthesized in the structural properties of SnO2 was presented. Samples (2wt.% La2O3, SnO2, 2 wt.% La2O3, SnO2, 1 wt.% Pt)were prepared using the ball milling method with m-xylene medium and they were calcined under700 °C. The thick film resistive paste based on SnO2 was fabricated on alumina substrate using screen printing technique. In order to prepare the printable thick film paste, the calcined resistive powders were mixed with organic vehicle and glass frit on alumina substrate with good rheology. Afterward, thermal treatment (drying and firing) was applied to dry the solvant from the printed paste and bonding the resistive paste on alumina substrate. The particle size and crystallinity of samples were characterized using X-Ray Powder Diffraction (XRD) spectroscopy and Transmission Electron Microscopy (TEM). TEM results illustrate that the obtained material are nanoparticles in spherical shape and the size of particles decreases with addition of Pt. The XRD pattern results show that the prepared samples are the nanopowders with almost spherical crystalline structure. The thick film surface morphology was investigated by Field Emission Scanning Electron microscopy (FE-SEM) before and after Pt doping and Energy Dispersive X-Ray spectroscopy (EDX) was used to determine the elemental composition.The results proved the nanometric size of all particles and it illustrated that the particle size of materials decreased with the addition of Pt on La2O3/SnO2

Patient Safety Behavior in Physicians: How is it Predicted?

Background: Patient safety is a serious global public health issue. Estimates show that every day many patients are harmed while receiving hospital care. Health care staff plays a key role in providing quality and safe patient care, especially physicians who are main members of the medical team and a critical element in patient safety efforts. Objective: The current study used a Theory of Planned Behavior (TPB) framework to investigate predictors of patient safety intentions and behavior of physicians. Methods: This descriptive analytical study was conducted in 8 hospitals with 52 physicians participating. A researcher-designed questionnaire was prepared to investigate patient safety behaviors and behavior constructs of physicians based on the guidelines of constructing a TPB Questionnaire: Conceptual and Methodological Considerations. The content validity and reliability of the questionnaire were confirmed. Binary logistic regression analysis was performed using SPSS18. Results: The total mean score of physician safety behavior indicated that 3.8±0.92. 42% of physicians reported their safety behavior at a good level. There was no significant difference between the patient safety function of physicians in public and private hospitals (P=0.8) and working in medical or surgical wards (P=0.4). Among TPB constructs, “normative beliefs” had the greatest influence on physician intention for safety behaviors (wald=3.828, P=0.05). Conclusion: The results showed that “normative beliefs” had the greatest influence on physician intention for safety behaviors; therefore, it seems that patient safety must be the most important concern of all health care staff, specifically managers and executives throughout health care centers

Assessing the Anatomical Variations of Lingual Foramen and its Bony Canals with CBCT

The purpose of this study is to investigate by means of CBCT the presence of lingual foramen and their bony canals in the midline of the mandible and to describe their anatomical characteristics. CBCT examinations of 200 patients were carefully examined in the median region of the mandible in order to detect the lingual foramen and their corresponding vascular canals. Their presence, number, position, diameter, morphology and trajectory were established. Lingual foramen in the midline of the mandible were observed in all 200 subjects. The number of canals varied from one to tree, with the following distribution: one canal in 39.5% of the cases, two canals in 53% and three in 7.5% of the cases. The average diameter of the canals in mesiodistal and buccolingual side were 0.749 and 1.029 mm. 17% of the vascular canals penetrated only the lingual third of the width, 62.5% reached the middle third of the mandible and 20.5% of the canals spread to the buccal third. As a conclusion we can say that CBCT is a useful tool in planning an implant treatment. It can reveal multiple anatomic features of the mandible, including the presence and the morphology of the lingual foramen and their vascular canals in the median region of the mandible. Clinicians should acknowledge the presence of these anatomical structures and should be aware of their possible implications

Rituximab therapy improves recalcitrant Pemphigus vulgaris

Pemphigus is a severe life-threatening blistering disease associated with autoantibodies against cell adhesion proteins desmogleins 1 and 3. Patients with severe pemphigus commonly show high rates of relapse after conventional immunosuppressive therapy. The newly developed drug Rituximab showed impressing promises in the treatment of refractory pemphigus vulgaris (PV). In the present study the efficacy of a single course rituximab therapy in the treatment of PV was investigated. Eighteen patients with severe recalcitrant PV were recruited to this study. Pemphigus disease activity index (PDAI), anti-desmoglein 1 and anti-desmoglein 3 antibody titers, and percent of CD20 positive cells were measured at baseline, 10 ± 1, and 22 ± 2 weeks after rituximab therapy. Rituximab was given intravenously at dose 375 mg/m2 once weekly for 4 weeks. Rituximab therapy caused a dramatic reduction in the PDAI, accompanied by decreases in anti-desmoglein 1 and anti-desmoglein 3 antibody titers over the follow-up course. The B-cell population decreased at the first follow-up, but returned to its baseline levels at the second follow-up. Rituximab therapy decreased the dose of immunosuppressive drugs required to control the disease. It seems that the rituximab may be effective and safe for treatment of refractory PV