Journal of Dental School
Year:2008 | Volume:26 | Issue:2 (76)|Papers Count:16

Background and Aim: A new root filling material, GuttaFlow, has been introduced by adding gutta-percha to RoekoSeal playing the role of gutta-percha and sealer simultaneously. The present study evaluated the cytotoxicity of two root filling materials GuttaFlow and gutta-perchaon mouse fibroblast cell line L929.Materials & Methods: GuttaFlow and gutta-percha were prepared according to manufacturer's instruction and exposed to UV radiation under the hood. After passage of mouse L929 fibroblast cells for 4 times, their vitality was assessed by tripan blue and counted by neobar devices. The counted cells were placed in the 24-well plates. The cell and dimethyl methacrylate were used as negative and positive controls. The fibroblasts were cultured at 37°C in a humidified atmosphere of %95 air and %5 CO2 in Dulbecco's MEM supplemented with %10 FBS containing penicillin (10 IV/ ml ) and streptomycin (l 0 mg/ml solution. 10 specimens of each experimental and control groups were brought into contact with the culture medium and incubated after 24 hours under sterilized condition. The cytotoxicity of each samples were assessed by MTT test after I hour, 24 and 72 hours. The results were analyzed using one-way and two-way ANOVA and Tukey multiple comparison interval.Results: There were a significant effect of material, assessment time and their interaction on optical density of material's cytotoxicity (p<0.0001 in all conditions), also it was revealed that assessment time had a significant influence on optical density of both materials.Conclusion: In GuttaFlow, the most and least cytotoxicity was observed at 24 and 72 hours while cytotoxicity of Gutta-percha increased with time.

Background and Aim: Endodontically treated teeth, because of extensive structural defect, have the increased risk of fracture. For desirable reconstruction of coronal tooth structure, the post provides retention, nowadays non - metal post systems were introduced to dentistry. This study compared the fracture strength of maxillary central incisors restored with metallic, fiber composite and ceramic posts.Materials & Methods: Thirty human maxillary incisors were used in this invitro experimental study. The crown of each incisor was cut off 1 mm coronal to CEj and perpendicular to the long axis of the tooth by metal disk. The root canals of the teeth were prepared for post after root canal therapy, then three groups of 10 specimen were formed. Teeth restored with Glass fiber, ceramic and prefabricated metallic posts and numbered as group 1, 2 and 3 respectively. Then, all teeth restored with composite core (Z100, 3M) and metal crowns were fabricated and cemented with glass ionomer vitremer luting cement. Specimens were embedded in autopolimerize acrylic resin 4 mm below CEj, and then secured in a universal testing machine. A compressive load was applied at 135 degrees angle to long axis with crosshead speed of 0.5 mm/min, till fracture occurred and fracture pattern was recorded. The data were collected and analyzed using ANOV A and LSD tests.Results: Fracture resistance by Newton was respectively: 765±113.26, 790±95.34, and 614±105.32 for glass fiber posts, ceramic and metallic groups. Resistance to fracture for glass fiber and ceramic posts was significantly more than Titanium post (P<0.05), but there was no significant difference between glass fiber and ceramic posts. Conclusion: Considering the results, usage of prefabricated glass fiber and ceramic posts are more preferable than prefabricated titanium posts. Because of more undesirable fracture in ceramic posts group than glass fiber, glass fiber posts are recommended.

Background and Aim: HIV/AIDS has been known as the most dangerous disease of the century. Moreover, special attention has been paid to teenagers who are more likely to be engaged in the AIDS complications. The present study aimed to evaluate the awareness and attitude of the students of the high schools at the north (district 1) of Tehran. Materials & Methods: In this cross -sectional study, a double stage random sampling was used and 640 students (357 girls, 283 boys) were evaluated. They were asked to complete an NCHS questionnaire consisting of 22 questions on awareness, 6 questions on attitude and 2 extra questions for obtaining information on AIDS. SPSS software, Kruskal- Wallis and Mann-Whitney tests were used to analyze the data.Results: The level of difficulty of more than half of the questions (13) was higher than 80%. A question from pathogenesis section of the questionnaire was found to be the most difficult one which had been answered correctly by only 24% of the subjects. The easiest question correctly answered by 96.6% belonged to etiology. Difficulty of coefficiency for all the questions of the means of transmission was higher than 80%. In the prevention section, half of the subjects were able to answer 5 questions out of 7, correctly. The least-aware fact was the availability of some drugs which enhance survival time of the patients. Asked to make a self-assessment in attitude section, 59% of the subjects placed themselves at the medium level. The most popular source of awareness was found to be TV and the least were hospitals and clinics.Conclusion: The results furnish an evidence of a satisfactory level of awareness of the subjects. The students had fear of infection, and most of them believed that the dentists are not able to diagnose the disease. With increasing the awareness, the fear and the anxiety of HIV could be reduced.

Background and Aim: The presence of fluoride in oral fluids is necessary for prevention of dental caries. The aim of this study was to determine the extent of fluoride retention in saliva after brushing with two Iranian fluoridated toothpastes, Nasim and Crend in comparison with Mac Leans & Crest.Materials & Methods: Ten adults used a nonfluoride dentifrice for 10 days before the experiment and between different stages of the experiment. The dentifrices included Nasim and MacLeans (with sodium monofluorophosphate) and Crend and Crest (with sodium fluoride). In each procedure, participants brushed their teeth with 1.5 gr of the dentifrices under trial for I minute. Saliva samples were collected at baseline, 1, 30, 60; 120 minutes after tooth brushing and fluoride ion were measured by potentiometry technique. The data were analyzed by Repeated Measurements, Paired t, One Way ANOVA and Tukey tests.Results: All dentifrices under this trial, had the highest fluoride concentration in saliva I minute after brushing (P<0.005) and after that time fluoride concentration decreased gradually. Crest toothpaste in comparison with Crend had higher fluoride retention in the 60 and 120 minutes [60 minutes: (0.9824±0.0988, 0.5173±0.770 (P<0.005); 120 minutes:(0.8103±0.0615, 0.3651±0.0580 (P0<0.008)].Conclusion: The Crest dentifrice showed the most fluoride retention in saliva, MacLeans and Nasim dentifrices had similar values of fluoride retention while the Crend dentifrice showed the least values of fluoride retention.

Background and Aim: Oral Recurrent Aphthous Ulcers (RAS), are among the most common oral mucosal ulcerations. The association of RAS with psychological factors has been reported in some of the previous studies. However, the results of these researches are controversial. The aim of the present study was to determine the prevalence of recurrent aphthous stomatitis and its relationship with anxiety in medical, dental and pharmaceutical students.Materials & Methods: In this study, the prevalence of recurrent aphthous ulcers, in 550 medicine, dentistry and pharmaceutics students of Kerman medical university, and the relationship between lesions and students' anxiety, were evaluated. Cattel anxiety questionnaire was used to assess the amount of anxiety. Another questionnaire was used, in order to evaluate the aphthous ulcers.T and Chi-squaretests were used to analyze the data. Results: Results showed that, 107 of 550 students (19.4%) had a positive history of oral recurrent aphthous ulcers. According to the patients' statements, mental stress, use of certain food, and exam induced stress, were the most important effective factors to aggravate the aphthous ulcers. The mean adjusted score of anxiety, anxiety intensity and mean rank of anxiety, in case group, were significantly higher than control group (P<0.001).These results showed significant difference between the two groups for the gender (P<0.05). Conclusion: According to the prevalence of recurrent aphthous stomatitis and its relationship with anxiety, prevention of anxiety or anxiety reduction should be noticed in the management of recurrent aphthous stomatitis.

Background and Aim: Mineral trioxide aggregate (MTA) is a relatively new material. It is biocompatible and has sealing ability. The purpose of this study was to evaluate the histologic pulp responses of calcium hydroxide and MTA placed directly on exposed pulp tissues.Materials & Methods: Twenty teeth already scheduled for extraction for orthodontic reasons were selected for this experimental study. These teeth were divided into 2 groups and treated with direct pulp capping. Calcium hydroxide was used for 10 teeth and MTA for 10 teeth. After 60 days the teeth were extracted and prepared for histological evaluation. Finally the data were analyzed with Mann-Whitney test. Results: All teeth treated with Calcium hydroxide showed inflammation. Internal resorption was seen in 6 teeth and abscess in 5 teeth and calcified bridge in 6 teeth and reparative in 2 teeth. Inflammation was seen in 2 mineral trioxide aggregate samples and calcified bridge and reparative dentin in 7 teeth. Internal resorption and abscess were not seen in mineral trioxide aggregate group.Conclusion: Mineral trioxide aggregate appeared to be superior to Calcium hydroxide as a pulp capping agent in primary teeth.

Background and Aim: Since there are rich mines of porcelain in Iran, dental porcelain production has been considered. Dentin porcelain was produced in previous projects. Color plays an important role in dental porcelain therefore, the aim of the present study was to identify different colors used in VitaVMK68 dentin porcelain and produce the similar porcelain in Iran and compare the quality and quantity of the produced colored samples with Vita samples.Materials & Methods: In this technical report, the best firing conditions was determined by XRD device. Dentin powder structure was evaluated by SEM. Chemical compound analysis and identification of colored particle found in Vita porcelain powder was done by different methods. In order to make colored dentin samples, compound colors with different formula and percentage, was added to dentin powder and after providing a homogenous compound, they were pressed and put in vita furnace for firing. The color of new dentin was examined with colorimeter and compared with vita dentin.Results: I) The results of X-Ray diffraction showed complete conformity of different phases in experimental dentin powder with Vita dentin powder. 2) Experimental dentin powder particle size was very similar to Vita dentin powder. 3) The main colors used in Vita dentin powder had crystalline structure and were the same as ceramic stains. 4) Sintered experimental colored dentin samples showed acceptable similarity to sintered Vita dentin samples (according to DE).Conclusion: Experimental colored dentin samples showed acceptable similarity to Vita dentin samples with no clinically perceptible color differences.

Background and Aim: There is no precise information of periodontal status in HIV-infected Iranian patients, so this descriptive study was performed to assess periodontal condition among HIV-infected patients referred to the three HIV patients medical centers in Tehran during 2005.Materials &Methods: One hundred & eighteen known HIV+ patients, confirmed by ELISA, Western blot and clinical examination, participated in this study. Data on age, gender, level of education, smoking, marital status, type of addiction, type of antiretroviral medicine, their dose and duration of consumption, etiology of their disease, and level of CD4 were recorded. None had surgery on neck and mouth.MGI, PI (Shick and Ash), PD, and CAL were measured on 6 surfaces of each of the Ramjord's teeth. Data analysis was done by SPSS, SAS, generalized estimated equation, hotte ling's multivariate model, Pearson and Spearman correlation tests.Results: One hundred & fourteen men (96.6%) and 4 women (3.4%) with mean age of 33.6±6.49 participated in the study. 14 persons (27%) had CD4<200, 29 patients (55.7%) had 200<CD4<500,and 9 (17.3%) had CD4>500. Mean MGI, PI, and PD were 1.33±0.41, 2.8±0.1 and, 1.66±0.98 respectively. There was no difference between CD4 and MGI and PI (P=0.1& P=0.2), but in patients with CD4<200, CAL was significantly higher than the other two CD4 groups (P=0.02). PD in this group was significantly higher than the otherCD4 groups (P=0.01).Conclusion: MGI and PI level in the study group were high which indicates poor oral hygiene. CAL was increased with immune system deficiency which indicates the influence of HIV-infection as a risk factor on the periodontal disease severity.

Background and Aim: Patients with fixed orthodontic appliances often experience an increase in the rate of dental caries. Appling chlorhexidine and tluoride is known to be an effective method to solve this problem since Mutans Streptococci is described as the most important bacteria related to the etiology of dental caries. The aim of this study was to evaluate clinically the application of a chlorhexidine-tluoride gel made in Iran on the level of Mutans Streptococci in plaque adjacent to bonded orthodontic brackets.Materials & Methods: In this double blind clinical trial 37 patients were selected. The patients were divided into 2 groups: those treated with chlorhexidine-tluoride gel five times with one week interval (group A) and those treated with placebo gel (group B). The level of Mutans Streptococci in the plaque of canine and second premolar of Maxilla before and after treatment was evaluated and compared by Wilcoxon Signed Rank test. The range of changes in group A was compared with group B by Mann-whitney test.Results: Statistical analysis showed a significant difference between baseline and final colony count results in group A (P<0.0001) but no significant difference in group B and also Mann-Whitney test showed a significant difference between the 2 groups (P<0.0001).Conclusion: Chlorhexidine-tluoride significantly decreased the level of Mutans Streptococci in plaque around the orthodontic brackets.

Background and Aim: Fear from dentistry procedures is one of the most prevalent conditions which can influence patient-dentist relationships. The aim of this study was to assess the rate of fear from different dental procedures in patients referred to the dental school of Kennan university.Materials & Methods: In this cross-sectional study, the rate of fear from different dental procedures in 386 patients referred to the dental school of Kennan University was assessed with the visual analogue scale by a questionnaire. Data were analyzed by t and ANOVA tests.Results: The results of this study showed that from 386 patients referred, 74 (19%) patients had low to moderate fear, 261(67.8%) patients had moderate to severe fear and 51(13.2%) patients had extreme fear. Most of the patients feared from surgery, root canal therapy, extraction and observing the syringe. The analysis of data showed that there was a significant relationship between fear, sex and previous unpleasant experiences. Women had more fear than men (P=0.012), and those who had unpleasant experiences feared more than those who did not (P=0.03). Fear decreased as the number of visits to the dentist increased (P=0.021). Conclusion: In spite of the differences in the rate of fear, dental procedures which cause the fear were the same in the patients.

Background & Aim: In fully edentulous patients, reconstruction with implant-supported fixed prosthesis is a complicated treatment. In conventional technique, after the placement of the implants, fixed temporary prosthesis is fabricated with no consideration of the removable prosthesis that the patient has used yet. Therefore, the logical relation of the phases of treatment is lost and the points such as vertical dimension occlusion and centric relation are not recorded exactly. The purpose of this article is to introduce a technique in which a fixed temporary prosthesis is fabricated by use of patient's full denture.Case Report: In this study, a 60-year-old patient with complete edentulous in the mandible was referred to Dental School. He has used a complete jaw denture in the mandible. The complete denture especially in the lower jaw has caused destructions to the remaining ridge. Due to the patient's condition and the existing circumstances, the treatment design of implant-supported fixed prosthesis was accepted by the treatment team. Prior to the surgery, assessments of the bone quality and quantity, force factors, the number of the implants, their lengths and angles were done and the complete denture was converted to implant-supported fixed temporary prosthesis.Conclusion: The fabrication of conversion prosthesis was introduced with implant-supported metal ceramic restoration.

Background and Aim: Contamination of soft denture lining materials and tissue conditioners with microorganisms is a common clinical problem. The aim of the study was to detennine the effect of adding eucalyptus (E) oil to viscogel tissue conditioneragainst bacterial and fungal growth on it.Materials & Methods: In this experimental study MIC (Minimum Inhibitory Concentration) of E. oil against Candida albicans and Staphylococcus areus was determined, then experimental specimen disks (diameter, 15mm, thickness: 2mm) with the amount of IMIC, 2MIC and without E. oil were fabricated under aseptic conditions. The samples were divided to II groups; each group contained 5 samples. One group was considered as control. The samples immersed into 1 ml of saline. After 24 hours 1ml of bacterial or fungal suspension with BHI broth medium was added. The growth of microorganisms was investigated after another 24 hours. This test was done for the samples at the concentration of 2 MIC of E. oil. The data were analyzed with Fisher's exact test.Results: The samples which were mixed with 1 MIC of E. oil showed antimicrobial effect in comparison with the controls (P= 0.024) after 72 hours. Samples of 2 MIC didn't show a significant inhibitory effect against S. areus (P=0.08) after 24 and 48 hours, but this effect was significant against C. albicans after 24h (P=0.024) and 48h in comparison with control samples (P=0.004).Conclusion: Addition of Eucaliptus oil significantly reduced the growth of microorganisms. The study showed that Eucaliptus oil leached out of tissue conditioner in 72 hours which is too short for clinical usage.

Background and Aim: Although bonding mechanism is based on resin diffusion onto the demineralized dentin collagen fibers in most of dentin adhesive systems, it has been shown that the bond is going to degrade over time. The aim of this study was to determine the effect of sodium hypochlorite on shear bond strength and bond durability of Excite to dentin.Materials & Methods: In an experimental study, buccal and lingual surfaces of 36 intact human premolars were prepared and randomly assigned to 4 groups. In groups 1 and 3, specimens were etched and bonding procedures were accomplished according to manufacturer's directions. Then, composite resin was bonded to the dentin surfaces. In groups 2 and 4, AD Gel (10% sodium hypochlorite gel) was applied in order to remove the collagen fibers after acid conditioning. Then, the bonding procedure was followed as for groups 1 and 3. After 24 hours, water storage in groups 1 and 2 and 1 year water storage in groups 3 and 4, shear bond strength was evaluated and analyzed by one way analysis of variance. Variance test was used for data analysis due to normal distribution of data and homogeneity of vanances.Results: ANOVA test showed that shear bond strength of group 1 (28.2±7.0 MPa) was significantly higher than group 2 (17.6±8.6 MPa) (P=0.001). The bond strength was also significantly higher in group 3 (29.4±4.7 MPa) than group 4 (21.3±8.0 MPa) (P=0.009). No statistical significant difference was found between groups I and 3 and also between groups 2 and 4 in terms of shear bond strength.Conclusion: Shear bond strength of Excite to dentin decreased with using sodium hypochlorite gel. Shear bond strength of Excite did not show any significant difference after one year of water storage, with or without using sodium hypochlorite gel.

Background and Aim: Periapical reparative process, following root canal therapy (RCT) depends on various factors, including the amount of extruded debris to periapical region. The amount of debris extrusion is a determining factor in periapical reparative process. The aim of this study was to compare the three debris extrusion from apical foramen in root canal preparation techniques; manual step back, rotary balanced force and rotary crown down.Materials & Methods: A total number of 60 single rooted teeth (incisor and premolar) were chosen non-randomly and were divided into 3 groups according to foramen diameter, root length, root divergence and the tooth type. The root canals were prepared according to standard techniques and debris extrusion was evaluated according to Montgomery method. The weights of debris were recorded by 10.5 gram precision. The data were analyzed by SPSS software version 13 using one way ANOV A and Post-Hoc tests.Results: Mean debris weight for the step back, balanced force and crown down techniques were 0.39±0.21, 0.22±0.09 and 0.26±0.12 mg respectively. The difference among three groups was statistically significant (P<0.05). The difference between the two rotary groups was not significant.Conclusion: Debris extrusion in manual step back technique was more than the rotary balance-force and crown down technique.

Background and Aim: The use of various techniques of teeth bleaching as a conservative and low-cost procedure is common and generally accepted today. The purpose of this study was to evaluate the bleaching effect of sodium perborate mixed with four different concentrations of H2O2 on artificial stained pulp less teeth.Materials & Methods: In this experimental single-blind study, 64 extracted human premolars were stained in vitro with human RBCs mixed with iron sulfide II, and randomly divided into 4 test groups and one control group. The bleaching agents of sodium perforate mixed with 7.5%, 15% and 30% H2O2 and distilled water was placed in pulp chambers of the teeth. The bleaching effects of each group were evaluated using a digital camera and L*a*b system. Adobe Photoshop 7.0 software was used to measure the color changes through the procedure. DE was used to describe color changes numerically. The data were analyzed by Kolmogorov Smimov, ANOVA and SPSS Ver. 9.0 software.Results: The results revealed that sodium perborate mixed with H2O2 30% significantly had more whitening effect than the other groups (P=0.001), but there was no significant difference among the bleaching effect of the other groups.Conclusion: The most bleaching effect was gained by H2O2 30%. On the other hand due to no significant difference between 15% and 7.5% of H2O2 with water, using sodium perborate mixed with water is one of the safest methods in teeth bleaching.

Background and Aim: Microorganisms' transmission ability in the oral cavity, suggest the possibility of re-infection of treated sites by microorganisms which are still present in un-treated sites. Thus, the purpose of the present study is to evaluate the clinical results of treatment of aggressive periodontitis patients in one session and multiple stages.Materials & Methods: Twenty patients of localized aggressive periodontitis were divided in two unique groups. Test group's surgery was done within 72 h and control group's surgery in 4 sessions with one week intervals. Plaque Index (PI), Gingival Index (GI), Bleeding On Probing (BOP), Pocket Depth (PO), Clinical Attachment Level (CAL) parameters were recorded at baseline and 4 and 8 months after treatment. Collected data were analyzed with SPSS 9 software, Kolmogorov-Smimov, Bonferroni, Student's T, Friedman, Wilcoxon, Mann-Whitney tests. Results: The findings showed that both treatment modalities resulted in periodontal improvements, however, GI and BOP parameters after 8 month were better in test group. Analysis of data showed pocket depth reduction in single rooted teeth in test group, in contrast to control group was better than baseline after 8 months, yet. In multi-rooted teeth pocket depth reduction in test group was also better and more stable than control group (P<0.05) and clinical attachment gain was better and more stable.Conclusion: Based on this clinical study it was shown that the pocket depth reduction and attachment level gain were better and more stable in multi-rooted teeth with single stage technique. Performed surgical procedures in single - rooted teeth resulted the same pocket depth reduction and attachment level gain in both groups.