Journal of Isfahan Dental School
Year:2019 | Volume:15 | Issue:1 |Papers Count:18

Introduction: Despite their ascribed intellectual ability and significant academic achievements, dental students’ academic performance is influenced by their academic motivation. This study examined the role of academic motivation in academic achievements of dental students in Kerman University of Medical Sciences. Materials & Methods: In this cross-sectional study, 172 dental students, from the 3rd to the final year, at School of Dentistry, Kerman University of Medical Sciences, completed the Inventory of School Motivation (ISM), comprising of 37 items and measuring 8 aspects of motivation. The gold standard for academic achievement was their overall average grades and their scores on basic sciences examination. Data were analyzed with SPSS 13. 5, using ANOVA, Pearson’ s correlation coefficient and chi-squared test at a significance level of p value < 0. 05. Results: Academic motivation had a significant and direct relationship with scores on basic sciences examination (p value = 0. 03) and the overall mean grades (p value = 0. 04). Areas of competition, effort and social responsibility had a positive correlation with higher average grades and scores on basic sciences examination. Competition motivation in male students was higher than that in female student. Conclusion: The results showed that students' academic achievement depends on their motivation.

Introduction: Increasing patients' expectations about restorative therapies and the beauty of researchers encourages researchers to study more about materials and methods that have the desired appearance for patient satisfaction. The purpose of this study was to evaluate theeffect of repeated firing on color changes of lithium disilicate (with high and low translucency). Materials & Methods: In this in-vitro study, 20 samples of high and low lithium disilicate were prepared forboth groups (n = 10). Samples were sectioned and polished to provide a thickness of 1mm. The specimens were subjected to firing for three times. The color coordinationafter the first and second firing were measured using spectrophotometer. Delta E was calculated between first and second firing. the data were analyzed by SPSS (version 16) stastical software (α = 0. 05). Results: The mean and standard deviation of low translucency was 1. 342 ± 0. 88 and high transcendental was 0. 757 ± 0. 49. Pair-wise comparison of color change prepared by three times firing in lithium dicliate samples caused higher Δ E of LDS with low translucent significantly (p value = 0. 019). Conclusion: Multiple firing casued significantly higher color changes in lithium disilicate with low translucency than that of with high translucent.

Introduction: One of the most important issues in pediatric dentistry is pain control during treatment. The inferior alveolar nerve block has some limitations as a conventional technique for the anesthesia of mandibular permanent molars, necessitating the use of alternative techniques, one of which is the infiltration technique. The aim of this study was to compare the efficacy of inferior alveolar dental nerve block using lidocaine with infiltration technique with articaine in mandibular first permanent molar anesthesia in children 8− 11 year of age. Materials & Methods: In this randomized cross-over clinical trial on 42 children 8− 11 year of age both mandibular first permanent molars were restored. Block or infiltration injection was selected randomly. Patient's behavior was registered in two steps of injection and restoration using the SEM scores. For comparison of the two sides, Wilcoxon signed rank test and SPSS 20 were used (α = 0. 05). Results: Based on the results, the infiltration technique resulted in a decrease in all the three SEM scores compared to block injection (p value < 0. 05). There was no significant difference in the efficacy of these two anesthetic techniques (p value > 0. 05). Conclusion: It appears that infiltration technique with articaine is a better alternative for block technique with lidocaine in the restoration of the mandibular first permanent molars.

Introduction: Implant-supported prostheses can be screw-type or can be cemented onto the abutment. Use of permanent cements, which are used in conventional prostheses, is not recommended for implant-supported prostheses. These cements are very strong and do not allow easy removal of the prosthesis. By using temporary cements not only permanent cement faults will be eliminated but also prosthesis can be retrieved as needed. The aim of this study was to evaluate the effect of screw access filling material and cement on the retention of implant cemented crowns. Materials & Methods: In this in vitro study, 5 angulated abutments (15° ) were screwed onto the analogue and ten crowns were fabricated for each of them. Four filling materials, Coltosol, composite resin, Teflon tape and silicone, were used to fill the access cavity and one abutment was left empty (only the screw was covered). Two temporary cements (Temp Bond and Temp Bond NE) were used to cement the crowns. The force required to remove the crowns was measured with a universal testing machine at a crosshead speed of 5 mm/min. Data were analyzed with ANOVA and Tukey test (α = 0. 05). Results: In all the samples, the force required to separate the casting crowns from the abutment were higher in Temp Bond NE group and this difference was statistically significant (p value = 0. 007). In addition, the difference between the access filling material was statistically significant (p value ˂ 0. 001). Therefore in each group, Coltosol, empty, composite resin, Teflon and the condensational silicone exhibited the highest means of separating force in ascending order. Conclusion: Retention of implant-supported crowns was influenced by types of filling material, access cavity and cement used.

Introduction: Pain control in dental treatment, especially in root canal treatment, is an important issue. The aim of this study was to investigate the effect of dexamethasone infiltration along with the inferior alveolar nerve block with lidocaine with 1: 80000 epinephrine on postoperative pain in posterior teeth with irreversible pulpitis. Materials & Methods: In this clinical trial, 60 patients with irreversible pulpitis and acute pain in lower molar teeth were selected and randomly divided into two groups. After standard block injection for each patient, buccal infiltration injections of dexamethasone or normal saline solution was performed. Preoperative pain was recorded using visual analogue scale (VAS) from 0 to 10 before treatment, and at 4-, 6-, 12-and 24-hour postoperative intervals. Data were analyzed with independent t-test and chi-squared, Mann-Whitney and Friedman tests (α = 0. 05). Results: There were no significant differences between the two groups in age, sex, tooth and pain severity before treatment. Pain in the control group 12 and 24 hours after treatment was significantly less severe than that at 4-hour interval; however, in the dexamethasone group this difference was not significant. By controlling confounding factors, preoperative pain significantly affected the pain after treatment at 4 and 6 hours. Gender affected pain at 12-hour postoperative interval. Conclusion: Buccal infiltration of dexamethasone significantly affected pain at 4-and 6-hour postoperative intervals. Preoperative pain significantly affected pain at 4-and 6-hour postoperative intervals in mandibular molars with irreversible pulpitis.

Introduction: An important consideration in newly introduced acrylic resins is to determine the flexural strength and color stability of dentures fabricated using these materials. The general aim of this study was to evaluate and compare the flexural strength and color stability of two injectable acrylic resins (IvoBase High-Impact and Vertex Castavaria) and a heat-cured acrylic resin (Meliodent). Materials & Methods: In this study, 30 cuboid samples were fabricated (10 specimens from each group), measuring 3 mm in thickness and 67×15 mm in dimension. The flexural strengths of the samples were determined using 3-point flexural strength test and their color changes were evaluated by immersion in tea using spectrophotometry technique. Data were analyzed with SPSS 22, using one-way ANOVA and HSD Tukey tests (α = 0. 05). Results: The mean flexural strength values of the IvoBase, Vertex Castavaria and Meliodent samples were 58. 16, 66. 01 and 77. 38 MPa, respectively. In relation to color changes, the Δ E values of IvoBase, Vertex Castavaria and Meliodent samples were 6. 56, 3. 59 and 6. 23, respectively. Conclusion: Meliodent heat-cured acrylic resin which uses the conventional system showed the best flexural strength, and Vertex Castavaria showed the best color stability.

Introduction: Implants are a successful method for replacing missing teeth. General dental practitioners interested in implants should have the necessary knowledge in this field to improve public health in order to provide their advanced dental services. This study aimed to assess the knowledge of dentists in Isfahan about problems and complications during and after implant surgery in 2017 in Isfahan. Materials & Methods: A total of 100 general dentists of Isfahan were selected for the purpose of this cross-sectional study. Questionnaires were completed by the dentists. Data collected from the questionnaires were analyzed with independent t-test and Pearson’ s correlation coefficient, using SPSS 22 (α = 0. 05). Results: Most dentists (78%) had low or average level of awareness. Age (p value = 0. 66) and experience of practice (p value = 0. 45) had no significant relationship with knowledge score. Mean knowledge scores of dentists who had implant therapy experience were significantly higher than the others (p value < 0. 001). Conclusion: The level of knowledge of general dentist was not adequate about the problems and complications encountered during and after implant surgery. In addition, the level of theoretical and practical education in particular in this area was limited and general dentists were not properly instructed in implant dentistry during their years of training.

Introduction: Infection control has always been one of the most important issues in dentistry. Dentists are exposed to harmful microorganisms originating from the blood and saliva. In prosthodontics contaminated impression materials are in contact with the laboratory personnel. Therefore it is absolutely necessary to establish a method for disinfecting these materials. The aim of this study was to survey the effect of three different disinfectants on alginate disks using the immersion method. Materials & Methods: The disinfecting efficacy of 0. 5% sodium hypochlorite, Deconex and Surfosept was evaluated in vitro by immersion method using 240 alginate disks contaminated with 3 microorganisms. Eighty alginate disks were prepared for each microorganism. The disks were immersed in the disinfecting solution. Cultures were prepared and colony counts were determined after 24 hours. Data were analyzed with chi-squared test and logistic regression using SPSS 20 (α = 0. 05). Results: The antimicrobial activities of 0. 5% sodium hypochlorite solution, Deconex and Surfosept were significant (p value < 0. 001). Surfosept exhibited the greatest effect on Staphylococcus aureus (mean colony count of 20. 05 ± 3. 28) while Deconex exhibited the greatest effect on Pseudomonas aeruginosa (mean colony count of 31. 15 ± 4. 27) and Candida albicans (mean colony count of 7. 55 ± 2. 37). Conclusion: The results of this study showed that 0. 5% sodium hypochlorite solution in all the three cases was the least effective. In the case of Candida albicans and Pseudomonas aeruginosa, the greatest effects were recorded with Deconex and for Staphylococcus aureus with Surfosept.

Introduction: Educative life is one of the most important aspects in every individual’ s life, which affects other aspects gravely. Emotional intelligence is one of the most effective factors in achieving success in different aspects of life. The present study was designed to investigate the relationship between educational status and emotional intelligence in dental students of Isfahan University of Medical Sciences. Materials & Methods: Bar-On questionnaire was used to evaluate emotional intelligence. This questionnaire has 2 parts: Demographic characteristics and emotional intelligence in 5 components (inter-personal, intra-personal, compatibility, stress management, general mood). The questionnaire was completed by 156 undergraduate students in Isfahan School of Dentistry. Student’ s overall average grades were used as an index for their educational status. Likert’ s 1– 5 scale was used for scoring. Data were analyzed with SPSS 18, using descriptive statistics, Pearson correlation coefficient and regression analysis (α = 0. 05). Results: The total scores of emotional intelligende were 223 and 218. 95 in female (71) and male (43) subjects, respectively. The total scores of single (91) and married (23) subjects were 223. 31 and 218. 13, respectively. In relation to accomodation, the highest mean, 224. 12, belonged to the subjects who lived in their own private homes (63) and the lowest mean, 209. 73, belonged to those living in rented houses. Self-esteem, mental pressure tolerance, happiness, empathy, and adaplabity were significantly associated with academic performance (p value < 0. 001). Regression analysis indicated that emotional self-awareness subscale (p value = 0. 014), self-esteem (p value = 0. 04), and happiness (p value = 0. 024) had a significant association with academic performance in the presence of other criteria and demographic features (r = 0. 770). Conclusion: The total score of emotional intelligence was highr in females compared to males. There was a significant relationship between students’ academic performance and type of living (living alone or with family). In addition, there was a significant relationship between academic performance and self-awareness, self-steem and happiness subscales.

Introduction: Amalgam is one of the most commonly used dental restorative materials, whose clinical use is still a matter of controversy among researchers. The alloy is criticized due to its mercury content and its dangers and limited resistance to corrosion in the body. In the present study amalgam/nano-hydroxyapatite and amalgam/nano-bioglass composites were produced to eliminate the currently existing limitations and evaluate the effect of the type of reinforcing agent on the mechanical properties and corrosion resistance of amalgam. Materials & Methods: In this analytical in vitro study, amalgam/nano-hydroxyapatite and amalgam/nano-bioglass composites with 2 wt% of nano-bioceramic were produced. Nano-bioceramic was added to the amalgam powder before adding mercury, followed by mixing with mercury in an amalgamator and compression in a steel mold. The microstructure of hardened samples was evaluated by scanning electron microscopy (SEM). In addition, the mechanical properties of the composites were evaluated using a universal compression test device. Resistance to corrosion of composites was studied by potentiodynamic polarization method. To compare the quantitative data, one-way ANOVA was performed using Graph Pad Prism 6 software (α = 0. 05). Results: The results showed that by increasing both bioceramics of hydroxyapatite and bioglass, corrosion resistance of composites increased, with hydroxyapatite exerting a greater impact on corrosion resistance of amalgam in the saline solution. In addition, incorporation of 2 wt% of bioglass and hydroxyapatite resulted in 12 and 15 percentages of improvement in the mechanical properties of the composites. Conclusion: The developed amalgam basic composites seemed to be good choices for restoration of posterior teeth, with less harmful effects (lower corrosion and higher strength), and hydroxyapatite nanoparticles were more effective than bioglass.

Introduction: The aim of this study was to evaluate the frequency of different types of medical errors in patients having complaints with no physical explanation, referred to Mashhad Dental Faculty Orofacial Pain Clinic. Materials & Methods: In this cross-sectional/descriptive-analytical study, records of patients referred to the Orofacial Pain Clinic of Mashhad Dental School from 2013 to 2017 were evaluated. A checklist consisting of the following was completed: type of complaint at the visit, method of treatment, diagnostic methods and referral pattern. All the patients had been examined by oral medicine specialists. Their complaints that could not be physically explained based on the history, clinical examinations and paraclinical tests had been evaluated, and the type of sensory disorder had been determined. Furthermore, all the patients had been interviewed by a psychiatrist to determine any psychiatric disorder. The frequency of different types of medical errors, diagnostic methods, psychiatric disorder and sensory impairment were determined and the possible connection was statistically analyzed. Data were analyzed with SPSS (α = 0. 05), using frequency tables, graphs and means and standard deviations. ANOVA, t-test and chi-squared test were used to compare the subgroups. In addition, if necessary, non-parametric tests of Mann-Whitney and Kruskal-Wallis were used. Results: The highest frequency of complaints at the time of visit was facial, mandibular or neck pain (74. 8%), and the lowest frequency was the complaint about a dull pain in the whole mouth. The most common treatment error was medication errors (49%), followed by tooth extraction. The most common error in diagnostic methods was radiography (65. 2%), followed by CT scan (24. 1%), and the lowest error occurred in sonography (2. 3%). Conclusion: Based on the findings of this study, when a patient with a complaint without any physical explanation is referred to the dental clinic, there is a high probability of diagnostic and therapeutic medical errors. Therefore, it is recommended that specific training programs be organized for dentists to identify complaints with a mental origin and their proper diagnosis or to consider referral of these patients.

Introduction: Frankel functional appliance is considered to be a very valuable device in the treatment of Cl II malocclusion, with the greatest skeletal effects. The aim of this study was to evaluate the dental and skeletal changes after treatment with Frankel appliance in patients with Class II malocclusion. Materials & Methods: This clinical trial was carried out on 8 patients, 9– 12 years of age, with Class II skeletal and dental malocclusion. Lateral cephalometric radiographs were prepared before and after treatment. Tracings were carried out on cephalograms and the necessary measurements were made. Data were analyzed with t-test (α = 0. 05). Results: Of all the variables on the base of the skull, comparison between the group treated with Frankel appliance and control group showed that SN height increased significantly (p value = 0. 006). Comparison between the two groups showed that in the maxillary complex, the decrease in SNA angle (p value = 0. 04) and the increase in maxillary height (p value = 0. 01) were significantly different between the two groups. In the mandible, gonial angle (p value = 0. 03), SNB angle (p value = 0. 001), SNBpog (p value = 0. 0005), height of the ramus (p value = 0. 01), base of the mandible (p value = 0. 007) and length of the mandible (p value = 0. 01) were significantly different between the two groups. Of all the variables created in the upper and lower jaws, the ANB angle (p value = 0. 0005) was significantly different between the two groups. Of all the variables, height and relationships of facial variables, S-GO (p value = 0. 01) and N-Me (p value = 0. 001) were significantly different; and of all the dental relationship variables the mean changes were significantly different between the two groups (p value = 0. 01). Conclusion: Frankel skeletal effects included prevention of maxillary forward growth and mandibular anterior movement, eliminating the mandibular deficiency and correction of the discrepancy between the two jaws. Frankel dental effects were minimum, decreasing the overjet and improving dental status in patients with class II malocclusion.

Introduction: Ameloblastic carcinoma is a rare malignant lesion with characteristic histopathologic features; however, sometimes these features are vague. Tumoral cells have an appearance similar to ameloblastoma but they exhibit cytologic atypia. On radiographic view, they behave similar to typical ameloblastoma. It might present as a cystic lesion with benign clinical features or as a large ulceration, with significant bone destruction and tooth loss. The lesion is often found after an incisional biopsy unexpectedly. Because of its aggressive behavior (extension to surrounding soft tissues, extensive bone destruction, lymph node involvement and metastasis), the treatment of choice for the lesion is wide excision. Regional lymph node dissection, radiotherapy and chemotherapy have restricted value for treatment. Close periodic evaluation of the patient is obligatory. Case Presentation: We report a case of ameloblastic carcinoma of the maxilla in a 46-years-old male patient, including radiographic, clinical and pathologic features. The clinical and radiographic views mimicked ameloblastoma, while histologic sections revealed cytologic atypia associated by ameloblastic carcinoma. The patient was scheduled for preoperative radiotherapy before radical surgery.