Journal of Isfahan Dental School
Year:2018 | Volume:14 | Issue:1 |Papers Count:17

Introduction: Metal-ceramic restorations have been commonly used in dentistry. These restorations have both the esthetics of porcelain and the strength and durability of metal. Noble alloys and base-metal alloys are usually used for metal-ceramic restorations. Applications of base-metal alloys has been developed because of economic considerations, mechanical properties and low density. Remelting of used alloys is a common way in dental labs to reduce the costs of fixed prostheses. Few studies have been performed on the effect of recasting alloys on the metal-ceramic bond strength. The purpose of this study was to evaluate the effect of commond alloy recasting on metalceramic bond strength.Materials & Methods: In this laboratory-experimental study, 23 waxed patterns in the size of 0.5´3´25 millimeter were cut with bisturi blade. Wax patterns were sprued, burned out and casted with commend alloy. The second group has the same method although they consisted of equal amount of fresh alloy and alloy remnants cast only once, the third and fourth group contained 50% fresh alloy and 50% used alloy of last group. After sandblasting, grinding and surface preparation, porcelain application was done with Noritake porcelain. samples fractured with 3-point bending test by Universal Testing machine at the speed of 0.5 mm per minute. Finally, the results were analyzed by ANOVA (p value=0.007).Results: The results indicate that the highest mean values of fracture strength of porcelain to metal was in the first group (30.9 N) and then squencely in the group 3 (28.7 N), group 2 (26.8) and group 4 (24.3 N).There is a significant difference between group 1 and 2 (p value=0.03), group 1 and 4 (p value=0.001) and group 3 and 4 (p value= 0.02). There was no significant difference between group 1, 3 (p value=0.26), group 2 and 3 (p value=0.3) and group 2 and 4 (p value=0.18).Conclusion: Recasting of base metal alloys statistically decrease the bond strength of porcelain to metal.

Introduction: It has been demonstrated that cytokines are important factors in the progression of periodontitis and some of them have an important role in the pathogenesis of periodontal disease. The aim of this study was to compare IL-23 levels in gingival crevicular fluid of patients with chronic periodontitis and healthy subjects. In addition, the relationship between IL-23 levels and probing pocket depths was assessed.Materials & Methods: In this in vitro study, samples were collected from the gingival crevicular fluid of 19 patients with chronic periodontitis and 19 healthy subjects, using paper points. The samples were transferred to the laboratory in transfer vials. IL-23 levels were determined using ELISA reader. The relation between IL-23 levels and probing depths was assessed. Data were analyzed with SPSS 20 using independent t-test and Pearson’s correlation coefficient (a=0.05).Results: The results showed statistically significant differences in IL-23 levels in GCF between healthy subjects and patients with chronic periodontitis, with higher IL-23 levels in patients with chronic periodontitis (p value<0.001). In addition, there was a significant and direct correlation between IL-23 levels and pocket depths in patients with chronic periodontitis (p value<0.001, r=0.811) and healthy subjects (p value< 0.001, r=0.858).Conclusion: Based on the results of the present study, IL-23 levels in gingival crevicular fluid can be used for the diagnosis of chronic periodontitis.

Introduction: OLP is a relatively common chronic inflammatory skin disease with an immunologic background that often affects the oral mucosa. OLR is a mucosal lesion, clinically and histologically similar to OLP, and can occur in the oral cavity in response to some drugs or synthetic materials. The risk of dysplastic changes have been considered in both lesions. On the other hand, OSCC is one of the most common malignancies of the oral cavity. The aim of this study was to evaluate and compare expression of cytokeratin-19 (CK19) in OLP, OLR, OSCC and normal oral mucosa in terms of their staining intensity and patterns.Materials & Methods: This descriptive-retrospective analysis was performed on 70 samples obtained from paraffin blocks of 20 cases of OLP, 20 cases of OLR, 20 cases of OSCC and 10 samples of normal oral mucosa. CK19 expression pattern and intensity of immunohistochemical staining were evaluated using Envision method. Data were analyzed with SPSS 20 using two-tailed regression test.Results: There seemed to be a significant relationship between suprabasal expression of CK19 and type of lesion (p value<0.001). In addition, the pattern of staining in OSCC and OLR patients was predominantly continuous and in patients with OLP it was predominantly interrupted. This staining pattern distribution was balanced in normal mucosa.Conclusion: Increased expression of CK19 was dramatically consistent with region (basal and suprabasal) and type of lesion. In addition, the pattern of expression of CK19 in OLR and OSCC was very similar. Therefore, perhaps this protein marker might be used as both a diagnostic tool to distinguish lichen planus from lichenoid lesions and as a detector in possible malignant transformation of lichenoid lesions.

Introduction: Idiopathic osteosclerosis is a localized growth of compact bone with an unknown cause. This lesion is asymptomatic and does not require treatment. The aim of this study was to determine the frequency of idiopathic osteosclerosis of jaw bones on panoramic radiographs.Materials & Methods: A total of 1122 panoramic radiographs of patients referring for dental treatment were collected in this descriptive study. Data on each radiograph were recorded, including age, sex, location of lesion (maxilla, mandible, and anterior, premolar and molar regions), relationship between the lesion and adjacent teeth (apical, apical and interradicular, no relation) and root resorption of the affected teeth. Data were analyzed with chi-squared test and independent-t test (a=0.05).Results: Frequency of idiopathic osteosclerosis was 7%. The lesions were more frequent in females than in males; however, the difference was not statistically significant (p value=0.195). The frequency of idiopathic osteosclerosis in the mandible, especially in the molar region, was significantly higher than that in the maxilla (p value<0.001). In addition, lesions with no relationship with tooth roots were significantly more frequent than those with a relationship with tooth roots (p value< 0.001).Conclusion: The frequency of idiopathic osteosclerosis was higher in females, in the area of mandibular molars and the late third decade of life.

Introduction: Dentists and all related oral hygiene occupations are endanger of cross contamination because of close contacts with patients. Dental laboratories are one of those which have a direct contact with dentist and cross infection control plays an important role to prevent exposure to pathogens. According to the fact that many dental laboratories are not well informed about cross infection control; the aim of this study is to prepare a questionnaire for evaluating both dentists and dental laboratories knowledge about cross control infections.Materials & Methods: 250 dentist and 50 dental laboratories were randomly chosen and prepared questionnaire distributed. The collected data were analyzed by SPSS software and Chi-Square test.Results: There was no significant differences between general and post graduated dentist in using gloves, masks and protective eye glasses (p value>0.05).the results showed no significant differences in uses of protective eye glasses between dentist who worked in clinics and private offices (p value=0.384), but there was significant differences in using gloves (p value=0.02).condensation silicones (90.5%) and alginates (90%) were the most impression materials and 88% of dentist rinsed the impressions always while 0.8% never did that.Conclusion: The cross control infection is not sufficient among dental laboratories and clinics and it is need to pay more attention.

Introduction: Given the importance of oral hygiene in preschoolers this study was conducted to study selection and usage of toothpaste pattern among 3-5 years old children in Yazd, Iran.Materials & Methods: In this cross-sectional study 200 children in range of 3-5 years old who brushed at least twice a week through interviews with their mothers and completing the questionnaire pattern of selection and toothpaste usage were examined for their children. Data were analyzed by SPSS software and Chi-square and t-tests and ANOVA analysis. The significant level of 0.05=а was considered.Results: Of the 200 children studied about 177 (%88.5) brushing teeth was done by the children themselves. The amount of toothpaste used for every brushing 76 people (%38) as much as a quarter of the brush, in 100 cases (%50) as much as half the size and in 24 cases (%12) it was the size of the size of the contact area.Conclusion: The high prevalence of brushing by child can not be regarded positive finding in this age rang. Since tooth brushing is very important in children under 6years it is necessary to raise the level of awareness of parents about the pattern of just brushing using toothpaste more efforts paid.

Introduction: Chemotherapy is one of the most common treatment modalities for blood malignancies such as leukemia, with several potential complications. Mucositis is one of the complications of chemotherapy, manifested with different severities. The aim of this study was to evaluate the prophylactic effect of vitamin E on reducing the severity of chemotherapy-induced mucositis.Materials & Methods: This randomized clinical trial was performed in Ahvaz’s Shafa Hospital on 56leukemic patients, undergoing chemotherapy. The patients were divided into 3 groups: 1) systemic treatment group, case group 1; 2) topical treatment group, the case group 2; and 3) control group. The oral mucosa of the patients was evaluated for the severity of mucositis and the patient’s response to pain. Data were analyzed with Mann-Whitney test and t-test (a=0.05).Results: In relation to the severity of mucositis, based on the results of Mann-Whitney test, there was a significant difference between the case group 2 and control group (p value£ 0.01). There was no significant difference between the two case groups (p value=0.2). In relation to the patient’s response to pain, there was a significant difference between the case group 2 and control group (p value £0.01). There was no significant difference between the two case groups (p value=0.4). Therefore, vitamin E decreased the incidence of thermotherapy-induced mucositis.Conclusion: Within the limitations of this study, vitamin E in its topical form is an effective medicament for reducing the severity and pain of chemotherapy-induced mucositis.

Introduction: Sutures are important intermediaries in the skeletal growth and biomechanical treatments, by changing their morphology during normal growth. The aim of this study was to observe and assess the changes in the morphology of mid-palatal suture in the age group of 8 to 25 years by using cone beam computed tomography (CBCT) images in an Iranian population living in Guilan province.Materials& Methods: This cross-sectional study done based on 128 CBCT images of the patients who referred to an Oral and maxillofacial radiology center in the city of Rasht at 1393 to 1394. Three line status of (1) vast distinct lucent, (2) slim distinct lucent and (3) indistinct and six marginal status of (A) smooth, (B) opened scallop, (C) closed scallop, (D) smooth to open scallop, (E) opened to closed scallop and (F) smooth to closed scallop identified and defined. Data analysis was done by Chi-square, Fisher's exact and one way ANOVA tests with the level of significance less than 0.05.Results: Vast distinct lucent and slim distinct lucent with frequency of %71.1 and %26.6 was the most common Line status of mid-palatal suture, in age range of 16-20 and 11-15 respectively. The most common marginal status was smooth (%57.0) in age range of 16-20, second was opened scallop (%25.0) in age range of 21-25, and closed scallop (%12.5) was the third common status that was in the age range of 11-15. From the point of view of the most marginal status in combination with line status smooth margin in connection with vast and slim distinct lucent was the common status with frequency of %64.68 and %41.2 that we observed subsequently, and the only indistinct line status was connected with closed scallop. There was no significant difference between sex, among mean age levels and totally among different age groups about form and marginal status of the midpalatal suture.Conclusion: It seems that chronological age and gender could not be appropriate standard criteriafor determining of developmental status of suture’s line and margin during growth.

Introduction: Polycarboxylate cement is one of the most commonly used cements in prosthodontics and in pediatric and restorative dentistry. However, the compressive strength and film thickness of polycarboxylate cement need to be investigated.Materials & Methods: In this in vitro study, 20 samples (10 samples from each cement) were used to test the film thickness and compressive strength of cements. Five samples from each cement were used to test the film thickness and 5 samples were used to test the compressive strength based on 1-12252A standard of Iran (ISO 9917-1: 2007). Data were analyzed with ANOVA (a=0.05).Results: The mean film thickness of Harvard and Ariadent cements were 26 ± 0.58 and 77.2 ±4.36 mm, respectively. The mean compressive strengths of Harvard and Ariadent cements were 67.68 ± 11.82 and 63.46 ± 5.42 MPa, respectively.Conclusion: According to the criteria set by the 12252-1 standard, Harvard and Ariadent cements exhibited film thickness higher than the standard, which was unacceptable. However, both cements exhibited acceptable compressive strengths based on the standard.

Introduction: Edentulism is an important problem for most people and unfortunately many do not take it seriously. The aim of this study was to determine the prevalence of edentulism and related factors in subjects over 20 years of age in Isfahan.Materials & Methods: In this cross-sectional study, 602 adults (301 females and 301 males) over 20 years of age were selected, from those referring to dental clinics in Isfahan. The prevalence of edentulism and its relation with age, gender, smoking, oral hygiene, medical history, periodical dental examination and education were investigated through questionnaires and clinical examination. Data were analyzed with Chi-Squared and Mann-Whitney tests and t-test (a=0.05).Results: The relationships between edentulism and variables such as age, smoking, caries, and periodontal disease, oral hygiene, periodic dental check-ups and education were statistically significant (p value<0.001). The relationship between edentulism and age was not significant (p value=0.77). The rate of edentulism was higher in the mandible.Conclusion: The prevalence of edentulism was related to factors such as age, smoking, oral and dental hygiene, medical history, lack of periodic check-ups and education; however, it did not exhibit a significant relationship with gender. Furthermore, the most important factors for tooth loss were periodontal diseases and caries.

Introduction: To investigate the outcomes of implants and prosthodontic treatments, it is necessary to have information about demographic, surgical and prosthetic variables of each patient. The aim of this study was to provide an organized collection of the implant success-related surgical and prosthetic data of patient records of the dental implant clinic of Isfahan Dental School from 1997 to 2013.Materials & Methods: This descriptive study was conducted on patients referred to Isfahan Dental School for placement of implants from 1997 to 2013. After accessing the patient records, the demographic characterization, medical and dental histories, follow-up information, as well as surgical and prosthetics data, were collected. Data were reported as frequencies and percentages.Results: The samples consisted of 2517 implants. The GBR technique was performed on 438 implants. The sinus lift technique had the highest rate in advanced surgical procedures in 158 implants. Autograft was performed in 7% of implants. Alloplast graft had the highest frequency in bone grafts (40.31%), followed by xenograft with a frequency of 38.9%. A total of 905 implants were bone level and 1532 were tissue level.Conclusion: Alloplast grafts had the highest frequency in GBR. Sinus lift was performed with 158 implants. The most commonly used implant brand was Zimmer.

Introduction: Antibiotics help resolve common infectious diseases. On the other hand, use of antibiotics is one of the most important reasons for resistance to antibiotics. Despite the necessity to administer antibiotics in many oral and dental diseases such as periodontal diseases, the pattern of prescribing antibiotics is inappropriate in many countries. The aim of this study was to evaluate the attitudes and practice of Isfahan general dental practitioners in relation to prescription of antibiotics in periodontal diseases.Materials & Methods: In this cross-sectional/analytical study, 140 general dental practitioners were selected using simple random sampling technique. A questionnaire with 9 questions on attitude and 7 questions on practice was submitted to each of them. Then the questionnaires were collected and data were analyzed with SPSS 22 using Pearson' s correlation coefficient (a=0.05).Results: The results of this study showed that according to the accepted standards, 85% (n= 119) of dentists had correct attitudes toward prescription of antibiotics in periodontal diseases, and there was no subject with incorrect attitude. The results also showed that 34.3% (n=48) of dentists had moderate and 65.7% (n=92) had good practice about prescription of antibiotics in periodontal diseases. In addition, there was no significant relationship between mean scores of attitude and practice (r=-0.05, p value=0.5).Conclusion: This study showed that general dental practitioners in Isfahan have acceptable attitudes and practice about antibiotic prescription in periodontal diseases, although this attitude and practice are far from the ideal.