Journal of Mashhad Dental School
Year:2009 | Volume:33 | Issue:3 (70)|Papers Count:12

Introduction: Today, much of the researches and innovations in dental materials are focused on simplification of the bonding procedures. The aim of this study was to assess shear bond strength (SBS) of three auto-adhesive dual-cured resin cements to dentin.Materials & Methods: In this in vitro experimental study, 40 intact human Third molars were selected and randomly divided into 4 groups of 10 teeth. Group I (Control group): After 15 seconds of etching and application of Excite DSC Bond (Ex), Varilink II (Var II) composite was injected into the plastic ring and light cured. Group II: RelyX Unicem (RX) was injected into the plastic ring and light cured after 30 seconds (according to manufacturer's instruction). Group III: Maxcem (Mc) was injected into the plastic ring and light cured after 30 seconds (according to manufacturer's instruction). Group IV: Multilink Sprint (MS) was injected into the plastic ring and light cured after 30 seconds (according to manufacturer's instruction). After thermal cycling (1000 cycle, 5-55oC), SBS were measured for each groups with a Zwick/Roell Universal Testing Machine. The data were analyzed by ANOVA and Scheffe tests.Results: The mean SBS and Standard deviations for groups I, II, III and IV were 12.95±2.64, 6.73±0.79, 3.01±0.90 and 4.60±0.75 MPa respectively. Statistical analysis revealed that: 1. The mean SBS of Var II was significantly higher than the other groups (P<0.05). 2. The mean SBS of Mc and MS were significantly lower than RX (P<0.05).3. The mean SBS of Mc and MS were not significantly different (P>0.05).Conclusion: Bond strength of the auto-adhesive dual-cured resin cements (RX, Mc, MS) to dentin was lower than Var II composite combined with Ex bond. Bond strength of RX was higher than Mc and MS.

Introduction: Hematologic deficiency appears to be an etiologic factor in some patients with recurrent aphthous stomatitis (RAS). The aim of this study was to investigate serum Iron, Zinc and Ferritin levels in patients with recurrent aphthous stomatitis referring to oral medicine department of Zahedan dental school.Materials & Methods: In this cross sectional analytical study, 30 individuals with aphthous lesions, 17 female and 13 male (case group) and 30 subjects without aphthous lesions, 17 female and 13 male (control group) were selected. All of patients referring to Oral Medicine Department of Zahedan Dental Faculty examined by Oral Medicine Specialist and diagnosis of recurrent aphthous stomatitis were conducted based on clinical criteria including round and symmetrical ulcers that covered by a yellowish white, removable membrane and are less than 1 cm in diameter and heal without scarring and encircled by an erythematous halo. 10 cc blood samples were taken from all the individuals and Iron, Zinc and Ferritin levels of them were measured. For statistical analysis we used Student t-test (P<0.05).Results: This study showed that the average serum Iron level in the case group was 90.92±31.8 mg/dl and in control group was 107.84±39.27 mg/dl. The average serum Ferritin level in the case group was 69.79±54.76 ng/dl and in control group was 87.82±83.92 n/dl. The average serum zinc level in the case group was l17.11±23.52 mg/dl and in the control group was 108.07±41.45 mg/dl. There was no significant difference between the two groups (P>0.05).Conclusion: According to the results, serum Iron, Zinc and Ferritin was not significantly different between the patient and control groups (P>0.05).

Introduction: Regarding to the difficulties and side effects of parenteral penicillin and considering the positive effects of high dose oral amoxicillin on acute odontogenic infections based on a previous pilot study, we decided to look for a practical and useful alternative treatment for parenteral penicillin. This study was planned to compare therapeutic effect of oral high dose amoxicillin with parenteral penicillin in treatment of acute odontogenic infections.Materials & Methods: In this clinical trial study, approved by ethical committee of Mashhad University of Medical Sciences, 56 patients with acute odontogenic infection were randomly divided into 2 groups. After obtaining informed consents, Patients in control and case groups were treated, respectively, by parenteral penicillin G and oral amoxicillin (2g three times a day). All of the patients were visited after 24 hour, 48 hour and 1 week intervals and the body temperature, pain intensity, size of the swelling and skin redness were recorded. Our criteria for improvement and responding to the treatment in this study were absence of fever, pain and redness and maximum reduction of swelling. Data were analyzed by Mann- Whitney and Fisher's exact tests through SPSS software (P=0.05).Results: 25 patients of control and 26 patients of case group were recovered (after 1 week) and no significant difference was found between the two groups (X2=0/0219, P=0.0639).Conclusion: Our study showed that high dose oral amoxicillin was as effective as parenteral Penicillin G without its side effects such as pain and anaphylaxis and could be considered as an alternative treatment in acute odontogenic infection.

Introduction: According to the large number of surgical removal of impacted third molar and prevalence of pain and side effects and importance of prevention to reduce these side effects and also presence of existing studies which show positive effects of prophylactic use of NSAIDs and antibiotics on healing after surgical removal of teeth and periodontal surgery, the present study was done to evaluate the effect of NSAIDs and antibiotics on pain and side effects after surgical removal of impacted third molar on patients referred to surgical Department of Tehran Azad university and two private surgical clinics in Tehran in 2008-2009.Materials & Methods: In this double-blind clinical trial study, approved by ethical committee of Azad University of Medical Sciences, 31 patients at the age of 17-27 who were candidate for bilateral impacted third molar extraction with the same difficulty index were recruited. Effects of naproxen-azithromycin combination (case side) and piroxicam-azithromycin combination (control side) were evaluated on pain, edema, dry socket, infection and trismus in different times. Data were analyzed with "Mann Whitney" and "Student t-tests".Results: From 60 evaluated samples, 24 were from maxilla and 36 were from mandible. Intensity of pain in study groups was lower in control group than the case group (P<0.001). Intensity of edema in study groups was also lower in control group than the case group (P<0.001). Intensity of maximum incisal opening in study groups was higher in control group than the case group (P<0.001). There was no sign of infection in patients but in one of them dry socket was observed.Conclusion: The result of this study showed that prophylactic use of piroxicam reduced intensity of pain, edema and trismus and it was more effective than naproxen.

Introduction: Fissure sealant therapy is one of the effective methods to prevent dental caries but because of saliva contamination, this method is accompanied by some problems. The aim of this study was to investigate the micro leakage of fissure sealant in isolated state in different time periods of contamination with saliva.Materials & Methods: In this in vitro experimental study, Ninety-two extracted human premolars were investigated in this study. A vertical groove was prepared on the buccal surface of each tooth and then the teeth were divided into four groups with 23 teeth in each group. Sealant therapy was done in isolated condition in the first group. The groove of each tooth in the second group was contaminated with saliva for 5s after washing up acid and then was dried and filled by fissure sealant. The groove of each tooth in the third group was contaminated with saliva for 10s after washing up acid and then was dried and filled by fissure sealant. This process was done for the forth group as well except for the contamination time with saliva which was 15 seconds in this group. Next, the teeth were undergone thermo cycling for 2000 cycles. After that, the teeth were immersed in a 0.5% basic fuchsine solution for 24h. Finally, the teeth were sectioned longitudinally in buccallingual direction and were examined and a ranked scale was used to score dye penetration. Mann-Whitney and Kruskal-Wallis tests were used for data analysis through SPSS 15 software.Results: In this study, Group 1 with 60.9% grade 1 leakage (no leakage) showed better results than other groups but statistical analysis did not demonstrate any significant differences in the degree of micro leakage of sealants between isolated state and 5 second contamination state (P=0.8).Conclusion: According to the results of this study, saliva contamination after washing up acid for 5s did not induce any further micro leakage.

Introduction: Researches about conventional soldering of base metal alloys have shown that they are unpredictable and too technique sensitive. The objective of this study was the introduction of cast to technique (casting for second time) and comparison of its flexural strength with conventional soldering.Materials & Methods: In this experimental in vitro study, 30 cylindrical metal patterns with 60mm length and 3mm diameter from base metal alloy "super cast" were prepared. Each was divided into two identical 30mm components by Cr-Co disc and subgrouped into two equal groups (N=30). In the first group, samples were placed on a plaster index with an interplaster distance of 0.3mm. Then this distance was filled with duralay acryl, and soldering process was accomplished on these 15 samples. In the second group, after creating an appropriate undercut at the end of each sample, specimens were attached with Duralay, a 10 gauge sprue with 12mm length was attached in the center of all samples and again the samples were burnout and cast with super cast alloy again. 3 point flexure test with zwick instron testing machine was accomplished and data were analyzed with F & T tests.Results: The flexure strength comparison of conventional soldering and cast to technique showed that there was no statistical difference between them. According to coefficient of variation, dispersive investigation of flexure strength for both groups was accomplished and showed that in soldering group, it was 1.5 times greater than cast to group.Conclusion: This study showed that flexural strength of cast to technique was comparable with conventional soldering. However, the results of cast to technique were more predictable than those of conventional soldering.

Introduction: GAgP is a multifactorial disease, which occurs in presence of bacteria and is influenced by genetic and environmental factors; leading to periodontal tissue dysfunction among subjects younger than 30 years. Proinflammatory cytokines are involved in immune response to periodontal pathogens through associating in inflammation phenomenon. It is supposed that gene polymorphisms of cytokines play a role in immune response and therefore in periodontal pathogenesis. In this study we assessed the gene polymorphisms of most important proinflammatory cytokines: Interleukin (IL)-1b +3954 C/T, IL-1a -889 C/T & Tumor necrosis factor-a (TNF-a) -308 G/A.Materials & Methods: In this case-control study approved by ethical committee of Mashhad University of Medical Sciences, after obtaining arm venous blood samples from patients (n=65) and healthy individuals (n=60) referring to Mashhad dental school, the DNA was extracted in Bu-Ali Research Institute. Restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) procedure was performed for determining polymorphisms. Data were analyzed by SPSS software V.15.Results: IL1b: CT, CC & TT genotypes in patients were 39.6%, 60.4% & 0.0% and in healthy individuals 41.7%, 50% & 8.3%, respectively. IL1a: CT, CC & TT genotypes in patients were 44.6%, 46.2% & 9.2% and in healthy individuals were 46.5%, 51.2% & 2.3%, respectively. TNFα: GA, GG & AA genotypes in patients were 44.8%, 41.4% & 13.8% and in healthy individuals were 46.7%, 50% & 3.3%, respectively. None of the differences was statistically significant.Conclusion: The lack of any association between the IL-1a, IL-1b, TNF-a polymorphisms and GAgP in the population presented here, brings into doubt the usefulness of these candidate genes as markers of susceptibility to this form of periodontitis.

Introduction: Oral cavity has been recognized as a potential reservoir for respiratory pathogens; so it is necessary to determine the role of oral infections in the occurrence and progression of respiratory infections. Therefore, a study was carried out to evaluate the relationship between periodontal disease and chronic obstructive pulmonary disease (COPD).Materials & Methods: In this study, 30 hospitalized patients with COPD (case group) were selected. The control group consisted of 30 individuals referred to Mashhad dental school at the same time who did not have any signs and symptoms of respiratory disease. The two groups matched in age, gender and smoking habit. After recording personal information of the patients, probing pocket depth (PPD), loss of attachment (LOA) and bleeding on probing (BOP) were determined in both groups. Finally, the data were compared and analyzed by Kruskal Wallis, Chi square and t-tests.Results: The mean age of patients in case and control groups were 53±7 and 54±5 years respectively. The number of smokers in the case group was 18 (60%); while there were 19 smokers in the control group (63.3%). The average loss of attachment (LOA) in the case group was 5.72±0.8 mm but it was 3.92±0.5 mm in the control group. The difference was significant (P=0.04). BOP was 86±12% in the case group and 71±16 % in the control group and there was a significant difference between the two groups (P<0.001). The average of PPD was 4±0.5 mm in the case group and 2.75±0.3 in the control group and there was a significant difference between the two groups (P=0.01).Conclusion: The data showed that all of the periodontal indices were significantly higher in the case group; It could be concluded that there was a significant relationship between periodontal disease and COPD.

Introduction: Nowadays, chewing gum is one of the frequent habits among people. The goal of this study was to compare the effect of two type chewing gums (with and without sucrose) on dental plaque accumulation in the lack of oral hygiene measures.Materials & Methods: In this cross over design clinical trial, approved by ethical committee of Azad Khorasegan University of Medical Sciences, plaque accumulation during three 4-day periods (with two week interval) was recorded (Sillness & LÖe Index) in a group of 20 volunteer male dental students, in the absence of normal oral hygiene methods. The stuents were asked to chew sugar-free gum (orbit) during the first4-day period and sugar containing gum (olips) during the second 4-day period and stop chewing during the third period. Participants were asked to chew five gum sticks daily after meals for about twenty minutes. The data were statistically analyzed using One Way ANOVA and LSD tests.Results: The results showed that both sugar free and sugar containing gums reduced the amount of plaque (P<0.000). The comparison of the mean dental plaque accumulation between the two groups indicated that the effect of the sugar free gum was significantly greater than that of the sugar containing one (P<0.001).Conclusion: Although sugar free gum is more effective than sugared gum on reducing dental plaque accumulation, chewing sugar containing gum also decreases the level of dental plaque.

Introduction: Lower lip is one of the most important structures in face aesthetics and function of oral cavity. This vital component is endangered due to trauma destruction caused by malignant lesions and therefore, it is important to restore function and beauty of this important part. The purpose of this study was to present the method of lower lip reconstruction with tongue flap.Results: A 40 years old woman with large lower lip destruction as a result of car accident was brought to Shahid Kamyab hospital, and reconstruction was done in three phases with the use of a tongue flap.Conclusion: It is important to be familiar with local flaps, especially tongue flap which has a good blood supply. Using tongue as a donor, it is expected to gain a high rate of success.