Journal of Dental School
Year:2006 | Volume:24 | Issue:1 (67)|Papers Count:18

Background & Aim: Extrusion of debris through apical foramen during instrumentation results in inflammation, pain and delayed healing. Thus, performing an instrumentation technique with minimum debris extrusion is preferred. The purpose of this study was to compare debris extrusion through apical foramen using Nickel Titanium rotary versus hand K- file instrumentation.Methods & Materials: Eighty extracted mandibular molar teeth (with separate orifices, canals and apical foramens in mesial root) were randomly divided into two groups. Teeth in group 1 were instrumented with rotary profile system; and in group 2 with hand Niti - K - file using crown down pressureless technique. Mean dry weight of apically extruded debris was compared by t- student analysis in two groups. Results: The mean weight of apically extruded bebris was 1.05 mg in Rotary instrumentation and 1.33 mg in Hand filing.Conclusion: Although debris extrusion in Rotary system is less than Hand instrumentation, there was no statistical difference between two groups. Probably the less debris extrusion in Rotary technique is due to the more taper of these files and preflaring compared to Hand files. Thus, if the crown down technique is used, the debris extrusion with hand and rotary instrumentation are approximately similar.

Background and Aim: Because of the importance of perfect and complete restorations in health of supporting tissues, this study was conducted to determine the prevalence of overhang in tooth-colored restorations which have been treated in operative department of Shahid Beheshti dental school during the year 1380-81. Methods & Materials: This was a descriptive study, done on 350 patients by undergraduate (9 and 10th semesters) and post graduate students in operative department of Shahid Beheshti dental school. Evaluation of overhangs were assessed according to grade of students, type and cavity surfaces, location of overhangs in relation to gingival margin, by means of observation, standard explorer and dental floss detection. In necessary cases, radiography was used for diagnosis. Chi - square test was used for statistical analysis.Results: Fifty two percents of all restorations had overhangs (10.9% C1 II, 15.2% C1 III, 17.5% C1 IV, 8.4% C1 V), which 22.8% of them were treated by students of 9th semesters, 28.2% by students of 10th semesters, and only 1% by post graduate students.Conclusion: In this study, proximal surfaces, C1 IV cavities and restoration at gingival level and among undergraduate students had more overhangs.

Background & Aim: Fluorine is the most important chemical element that changes the tooth surfaces, therefore it's consumption within the permitted range is useful for dental health, but it's decrement or increment over the optimal range causes damages to different body and dental systems. The amount of flouride in surface water has been stated to be about 0.5 mg.l which is less than the optimal level of flouride in drinking water suggested by WHO (1 ppm). According to study of the ministry of health and medical education in 1998, more than 68% of drinking water in Khoozestan province is provided from surface water resources and fluorosis and dental caries are seen abundantly in the province. In order to determine the role of fluoride this study has been made to evaluate the prevalence rate of fluorosis and DMFT and also compare them in Maroon, Karoon and Karkheh branches. The purpose of this study was to determine the prevalence of hypodontia in 15year old students (boys & girls) in AHWAZ on 2002.Method & Materials: During this analytical descriptive study, 1152 twelve to fifteen years old students were examined regarding different fluorosis rates (Dean index) and DMFT rate (WHO index). Each student had a questionnaire including demographic in formation, oral hygiene status, caries and fluorosis. Collected data was analysed using T, chi - square test and Spearman - Pearson tests.Results: Prevalence of fluorosis in Maroon, Karoon and Karkheh branches was 62.2%, 34.9% and 57.3% respectively; and the average of DMFT was 1.33, 1.20 and 0.6. Increase in fluoride level caused increase in fluorosis prevalence (P<0.001).Fluoride increment in drinking water and prevalence of fluorosis have been accompanied by DMFT decrement in Karoon and Karkheh branches, but in Maroon branch, with fluoride increment of drinking water and prevalence of fluorosis; DMFT also increased. The evaluation of different Dean index rates show that: the caries free rate has decreased from degree 2 to degree 5.Conclusion: In Khoozestan province, in spite of low level of fluoride, lower than the level suggested by WHO; the tropical climate, high level of sea foods consumption and possibly the high interest of people of this region to drink tea have caused high level of fluorosis. Beside the mentioned factors, the effect of economic and cultural verity in this province is seen from the result of this study.

Background & Aim: Orthographic surgeries are performed for cosmetic and medical reasons. The basic changes in orthognathic surgeries are done over skeletal and tooth sections and hard tissue movements are accompanied with soft tissue changes. Furthermore, the patients' response to the surgery and imitation of soft tissues from skeletal and teeth movements are very important. Therefore, this study was carried out in order to evaluate soft tissue changes in patients went under orthogenetic surgery using profile photographs at Taleghani General Hospital in 1999.Methods & Materials: The study was a quasi - experimental one, using observation as its technique. Profile photographs in natural head position (NHP) were used. Three lines (true horizontal line, constructed vertical line, and tragocontal line) were selected and soft tissue landmarks changes' were analyzed, considering true horizontal line and constructing vertical line. Photographs were taken before the surgeries and six months after IMF opening. The hard tissue changes were calculated with reference to cephalometric analysis provided before the surgeries and six months after IMF opening. Eight soft tissue landmarks and five hard tissue landmarks were used in this study.Results: The study showed spontaneous hard and soft tissue changes during orthogenetic surgery, while there was significant statistical correlation between soft and hard tissue changes.Conclusion: 1- Soft tissue changes are followed by hard tissue changes. 2- Considering age, sex, race, and medical history of the patients are very important before orthogenetic surgery.

Background & Aim: The effects of sociocultural status on periodontal condition in pregnant women have been reported by a number of researchers. Based on the latest researches and statistics it is concluded that periodontal disease is an important risk factor, leading to preterm delivery or low birth weight baby.Method & Materials: This study evaluates the periodontal condition of 148 pregnant women based on CPITN index, and relation between the demographic (age, professional and education level, month of pregnancy, number of children, number of pregnancies) and clinical variable (previous dental care, frequency of tooth brushing). The x2 test was used to analyze the data.Results: The results of study showed that %14.2 had Pregnancy tumor and %37/8 had gingival enlargement. CPITN index is increased in trimesters and aging. There was a significant relation between CPITN and age (P= 0.004), education level (P=0.000), professional level (P=0.0001) number of pregnancies (P=0.021), number of children (P=0.034), present month of pregnancy (P=0.000) previous dental care (P=0.045) and frequency of tooth brushing (P=0.000).Conclusion: In view of the results of our study, it might be suggested that simple preventive oral hygiene program helps to maintain healthy gingival and periodontium during pregnancy.

Background & Aim: The aims of this study were to assess the impact of dentofacial relationships and sex on: Self evaluation and self satisfaction in 12-15 years old students in Qazvin in 2003, and to determine the correlation between type of school and variables determining malocclusion with self evaluation and self satisfaction.Method &Materials: A cross - sectional study two stage - cluster sampling was carried out among 120 students (58 girls, 62 boys) aged 12 - 15 years who attended 4 guidance - schools (2 public, 2 private) in Qazvin in 2003. All samples were examined clinically and a questionnaire was used to assess their self evaluation and self satisfaction. Data were analyzed by the means on Chi - square and Fisher exact test.Results: Overjet, crowding and severe maxillary irregularity were significantly related to self evaluation. Overjet and severe mandibular irregularity were related to self satisfaction. No sex difference was found. Type of school was not a significant factor affecting self evaluation and self satisfaction. High level of self satisfaction has been found in the students. However, the majority of student had mid level of self evaluation.Conclusion: Overjet is the only variable significant in 12-15 year old students affecting both self evaluation and self satisfaction. Subjective esthetic measure should be incorporated to clinical esthetic criteria. Good communication between dentist and patient is important in analyzing and planning esthetic treatment according to individual needs and desires.

Background & Aim: Although keratinized gingival is not necessary for the maintenance of periodontal and peri-implant tissue health if oral hygiene is adequate, its presence is generally advocated especially in some cases. In this study, 3 surgical procedures were compared in their ability to increase the width of keratinized tissue.Method &Materials: In this controlled randomized clinical trial, twenty-one cases with inadequate keratinized tissue were randomly assigned into I of the 3 study groups including standard free gingival graft (SFGG) and strip technique free gingival graft (STFGG), free connective tissue graft (CTG). All the cases were followed up for I to 6 months. The qualitative variables (e.g., color match, patient & periodontist's satisfaction, graft contour and need for recontouring) were compared by using the chi-square test. Furthermore, in order to comparison of the width of keratinized gingival among the study groups, the Kruskal-Wallis test was used.Results: All of the surgical procedures resulted in a statistically significant increase in the width of keratinized tissue (SFGG: 5.28mm, STFGG: 6.50mm, and CTG: 5.00mm). The results were improved six months later only for the first 2 techniques. The best results in esthetics were obtained in CTG and were significantly higher than the other groups (P<0.05).There was a significant difference between the success rates of the three surgical methods (P= 0.015). These rates were 100% for STFGG, 28.6% for CTG and 57.1% for SFGG.Conclusion: For selection the best technique in increasing the width of keratinized tissue: if the greatest amounts of keratinized tissue is considered, FGG or strip technique is advocated and if esthetic considerations is critical, FCTG and in considering both of them, strip technique may be the better choice.

Background & Aim: The purpose of this study was to determine the prevalence of hypodontia in 15 year old students (boys & girls) in AHWAZ on 2002.Method & Materials: This study was a descriptive Cross Sectional investigation with randomized cluster sampling on 866 Students (15 years old). Data collection is done with radiography, questionnaire and clinical examination.Results: The radiographical prevalence of hypodontia (excluded third molars) was %4 that in females (%4.8) was more than males (%3.4), that isn't significant (p=0.3). The order of frequency of congenital missing is:1. Maxillary lateral incisors (%35.8).2. Mandibular second premolar (%28.4).3. Mandibular central incisor (%8.9).The congenital missing teeth on maxilla are more common.Conclusion: Hypodontia is more common on girls and maxilla. The order of congenital missing is: 1. maxillary lateral incisor, 2. mandibular second premolar and 3. mandibular central incisor.

Background & Aim: The bond strength of restorative materials to dentin plays an important role in their clinical longevity. However since clinical trials are time consuming and costly and owing to rapid progressive in adhesive bonding systems, it's essential to find a simple, rapid and standard method to evaluate the bond strength of bonding agents in laboratory tests. The purpose of this study is to evaluate the effect of different cross-head speeds on shear bond strength of two dentin bonding systems belong to fourth generation (Scotchbond Multi-Purpose) and fifth generation (Single Bond) and classify the failure modes (adhesive, cohesive or mixed).Methods & Materials: The buccal surfaces of 80 intact premolars were ground by a wheel shape diamond to the tip of the buccal cusps until the dentin is exposed. Then the buccal surfaces were flattened by paper discs with air and water spray. Finally, all samples were etched by 35% phosphoric acid. Afterwards the etched samples were divided into two 40 groups. Scotchbond Multi-Purpose was used for the first group and Single Bond for the second one. Then the Z100 composite was connected to the samples by 3x5 mm plastic molds. Each 40 group was divided by four 10 batches. Afterwards, the shear bond strength of each batch was determined by Dartec machine at four different cross-head speeds (0.5, 1, 2 & 5mm/min). After this step, the failure mode of the specimens was determined with stereomicroscope (56×). The quantitative variables were analysed with one way ANOVA and Duncan test and the qualitative variables were analysed with chi - square and fisher tests.Results: Statistical analysis showed that in Scotchbond Multi-Purpose group there were no significant differences between mean shear bond strength and failure mode of the samples that were tested by cross-head speed of (0.5 & 1mm/min) & (2 & 5 mm/min), (P>0.05), but significant differences were observed (P<0.001) between batches that were tested by cross-head speed of (0.5 & 2 mm/min), (0.5 & 5 mm/min), (1&2 mm/min) & (1&5 mm/min). In the Single Bond groups there were no significant differences between mean shear bond strength and failure mode of various batches that were tested in difference cross-head speed (P>0.05).Conclusion: Evaluation of shear bond strength and failure mode of dentin bonding systems showed that they depend on the different cross-head speeds. However, the cross-head speed less than 1mm/min makes adhesive failures. Therefore it's preferable for shear bond strength tests.

Background &Aim: It is not well established that why certain parts of gingiva are more susceptible to some kind of periodontal diseases, since these regions are adjacent to the foramen of some nerves and paths, and regarding to the important role of neuropathies in inflammation. On the other hand, it was shown that SP and CGRP have some role in periodontal diseases, so the aim of this study was to determine the correlation between concentration of SP and CGRP and different regions of human clinically healthy gingiva.Methods & Materials: For this analytical study, 17 gingival samples from first maxillary incisor and first molar regions (case group) and 23 gingival samples from other regions (control group) were collected. Tissue samples were cultured for 72 hours. Then EIA was used for detection of SP and CGRP in supernatant fluids. Statistical analysis was made by Mann - whitney U test and Spearman's correlation coefficient tests.Results: Both SP and CGRP were present in all samples. There was also significant difference between different gingival regions regarding to CGRP concentration so its concentration was lower in first molar regions (P≈0.023). We could not find any significant difference between different regions regarding to SP concentration.Conclusion: It is suggested that SP and CGRP probably participate in the regulation and maintenance of gingival health and based on the lower concentration of CGRP in the gingiva of upper and lower first molars, it could be suggested a possible cause for susceptibility of these regions to some of oral diseases such as localized aggressive periodontitis.

Background & Aim: The application of immunohistochemistry methods has resulted in marked improvement of the microscopic diagnosis of neoplasms combined with H&E staining. Although unique cellular antigens have not been found in salivary gland neoplasms, multiple less specific immunomarkers have been used and may be helpful in elucidating the role of myoepithelial differentiation in those neoplasms. The aim of this study was to evaluate immunohistochemical myoepithelial markers (GFAP, actin, vimentin and s100) in mucoepidermoid carcinoma and pleomorphic adenoma of salivary glands, for differential diagnosis of these tumors and specification of their histogenesis.Method & Materials: Formalin-fixed and paraffin embedded tissue sections of 25 pleomorphic adenoma and 25 mucoepidermoid carcinoma were immunohistochemically analyzed for the presence of actin, vimentin, GFAP and S100 protein. A standard biotin-streptavidin procedure after antigen retrieval was used. Immunoreactivity of myoepithelial cells and chondromyxoid areas in pleomorphic adenoma and mucus cell, epidermoid cells and intermediate cells in mucoepidermoid carcinoma were evaluated and immunoreactivity was scored on a scale of 0 to +4 (Regezi method) with 0 as negative, 1+ scattered staining, 2+ indicate 25% to 50% of positive tumoral cells and 4+ indicating more than 50% positive cells. The data were ana1yzed with chi-square test, and significant level 0.05 (P<0.05).Results: In 25 pleomorphic adenomas all nonluminal cells and chondromyxoid areas were positive (+4) for GFAP and vimentin and (0→+3) for muscle-specific actin (12:0, 12:+1, 1:+3) and (+1→+4) for S100 protein (3:+1, 3:+2, 18:+3, 1:+4). But all mucoepidermoid carcinomas regardless of their grade were negative for all mentioned markers (P<0.001) and there were no immunohistochemical difference in major and minor salivary glands neoplasms.Conclusion: Expression of myoepithelial cell-associated markers in pleomorphic adenoma have confirmed role of myoepithelial cells in histogenesis of this tumor and lack or limited expression of these antigens in mucoepidermoid carcinoma indicates the minimal myoepithelial differentiation in this tumor. Therefore, evaluation of myoepithelial cell markers can be helpful in differential diagnosis of salivary gland neoplasms with myoepithelial cell differentiation, and also specification of histogenesis of these tumors.

Background & Aim: Herpes simplex virus is responsible for many infections in various parts of the body- Type I is the cause of two oral diseases: acute gingivostomatitis and cold sore. Many drugs have been recommended in this field; each of which has its specific side effects. Introducing a kind of herbal drug which has therapeutic properties could be a good one for this purpose. This study was designed to investigate the antiviral effect of Garlic and the use of it as an herbal drug in the treatment of HSVI infections.Methods & Materials: Hela cell culture was used for several assays in this experimental study. The required virus was collected from infected patients. After increasing the amount of virus, it was titrated by TCID50 assay via cell culture. Finally, the cytotoxic doses of Garlic extracts were determined in cell culture and the antiviral doses were assessed.Results: The doses that caused 50% of cells death in cell culture (CC50) respectively for aqueous and alcoholic extract were: 2.9lmg/ml and 3.05mg/ml. The doses that caused 50% reduction in the virus cytopathic effect (IC50) were: 1.13 and 0.98mg/ml.Conclusion: It is obvious that both types of Garlic extracts had a significant antiviral effect on HSVI. On the other hand Garlic had cytotoxic effect that appeared in the higher doses than antiviral doses.

Background & Aim: Inappropriate drug prescription by health professionals is common, even in developed countries. Since there was no report on pattern of dentist's drug prescription in Iran. This study was conducted to evaluate the characterization of drug prescribing practices through one year period in Kerman province. Methods &Materials: This study was a cross - sectional analysis of 850 prescriptions which were randomly selected from 10500 dentists prescriptions in treatment Insurance organization of Kerman province in four seasons of 2001. Then 210-215 prescriptions for each season were analyzed for age and gender of the patients, drug category, name of the drugs, and the route of administration. Results: There were no significant differences between the age and sex of the patients admitted by dentists in Kerman province in 2001. The mean number of drugs per prescription was 2.03±0.64 in Kerman province.Most of the prescribed drugs (81%) were administered orally. Antibiotics (82.2%), non-steroidal anti-inflammatory drugs (NSAIDs) (62%) and analgesics (32.7%) were the most frequently prescribed drugs. Amoxicillin (50%) was the most common antibiotic, and Ibuprofen (34.3%) and Mefenamic acid (26.5%) had the highest frequency of administration among NSAIDs prescribed by dentists.Conclusion: The results of this study showed that dentists in Kerman province had good prescribing performance about the number of drugs per prescription, but antibiotics and NSAIDs prescription rates were much higher than other reported studies. This issue may reveal the need for a change in prescribing pattern of dentists.

Background & Aim: In addition to microorganisms, several other factors such as host immune responses are also involved in pathogenesis of dental caries. Among the factors of immune system, the role of neutrophil in prevention or pathogenesis of dental caries is not well studied. So the aim of this study was to investigate the correlation of neutrophil chemotaxis and dental caries.Methods & Materials: In this analytical study, fifty dental students with dental caries were selected. 10 ml of heparinized blood were collected from subjects for neutrophil chemotaxis test by modified Boyden chamber method. Statistical analysis was made by ANOVA, t test and Pearson's correlation coefficient.Results: The amount of neutrophil chemotaxis in the above subjects was 94.38±12.08 micrometer. Statistical analysis did not show any significant difference regarding to neutrophil chemotaxis in different degrees of DMF. But by comparing neutrophil chemotaxis with the degree of active caries, significant differences were shown between 0 and 5 degrees; (p≈0.000) and 1 and 5 degrees (p≈0.016) of active caries regarding to the mean of neutrophil chemotaxis.Conclusion: It is suggested that not only deficiency in neutrophil chemotaxis is not assumed in pathogenesis of dental caries, but also there is a direct correlation between neutrophil chemotaxis and the degree of active caries. Of course more studies are needed in order to prove this hypothesis.

Background & Aim: People in some areas of Ramsar, a city in northern Iran, receive an average whole body dose, that is about 5 times higher than the normal background radiation level. The high background radiation in these areas of Ramsar is primarily due to the presence of very high amounts of 266 Ra and it's decay products (like radon), which are brought to the earth'sc surface by hot springs. 226 Ra is chemically similar to Ca and tends to accumulate in bones and teeth. The object of this study was to evaluate dental & periodontal health status of the people residing in the high background radiation areas (HBRAs) of Ramsar, compared to a control region (with much lower level of natural radiation), in this city.Method &Materials: This analytic case-control study was accomplished on 322 people aged 15-75, residing in Talesh Mahaleh & Chaparsar, as the case group and Talesh Mahaleh of Katalom, as the control group. The method of collecting the data, was all-counting. CPI, DMFT indices were considered to evaluate dental & periodontal health. SPSS11 and SAS 8 softwares were used for the data analysis.Results: Considering the highest CPI codes, there was a significant difference between two groups (p<0.05): 1.1% and 6.9% of the subjects had normal periodontium (code 0), 9.6% and 13.9% of the subjects had bleeding on probing (code 1), 50.6% and 49.3% of the subjects had subgingival calculus (code 2),35.4% and 25.7% of the subjects had shallow pockets (code 3),3.4% and 4.2% ofthe subjects had deep pockets (code 4), in HBRAs and the control region, respectively. Concerning codes 3 & 4 together, as the major periodontal disease level, the percentages of this level were 38.8% and 29.9% in the case and control groups, respectively. There was a significant difference in DMFT, between HBRAs and the control group: mean D was 5.77±3.47 and 4.70±3.72 (p<0.05), mean F was 1.19±2.09 and 0.51±1.37 (p<0.01), and mean DMFT was 13.13±6.10 and 10.83±6.61 (p<0.01), in two regions, respectively. There was no significant difference in mean M between the two groups (p>0.05).Conclusion: Considering the DMFT and CPI scores, we can conclude that the condition of dental and periodontal health in people residing in HBRAs of Ramsar is different and poorer from the control area. These results can't be explained by the differences of gender, age group, literacy, smoking, frequency of brushing, dental attendance and the kind of drinking water, between two regions. It seems that being exposed to high levels of natural radiation can contribute to the findings.

Background & Aim: The aim of this study was to determine the effect of chemo-mechanical caries removal on microleakage of compoglass restorations in primary molars.Methods & Materials: In this experimental study 70 primary molar teeth with proximal caries were selected and divided into two groups. In one group the caries were removed with round bur and in the other group with carisolv gel. Samples were restored with compoglass restoration material, then thermocycled.The surfaces of teeth were sealed with two coats of nail varnish 1-2mm short of the margins and were immersed in basic Fushin solution for 24 hours at 37°C and sectioned mesiodistally. The extent of dye penetration was evaluated with Olympus stereomicroscope at 40x. The data were analyzed qualititatively (Chi square and proportions statistic test) and quantitatively (T test).Results: Qualitative test showed that, dye penetration in gingival and axial walls in chemo-mechanical group is significantly lower than mechanical group. Quantitative T test also showed that dye penetration length in gingival and axial walls in chemo-mechanical method is lower, and their difference is significant.Conclusion: The extent of microleakage in compoglass restorations after caries removal with chemo-mechanical method is lower than with mechanical method; therefore, it can be replaced by conventional method, if necessary.

Background & Aim: This study was carried out to compare the microshear bond strength of Clearfil SE Bond between the two different regions of primary tooth: incisal and cervical.Methods & Materials: In this experimental study which was controlled in vitro trial, 20 extracted primary canines without any caries, fracture and structural anomalies were disinfected and stored in normal saline of a room temperature. Every tooth was hemisectioned buccolingually via ground section. From the two resultant mesially and distally sections, one was chosen for the test, randomly. The composite resin material (Ap-x;A2) was placed and packed into the micro bore tygon tubing with the height of 1mm and internal diameter of 0.7 mm. After application of self - etching primer (according to the manufacturers' instructions) over the incisal and cervical (buccal aspect) dentin, tygon tubes containing composite, were placed over these areas and cured for 40". Microshear bond strength was determined using the microshear machine and also mode of failure was investigated by stereomicroscope in addition. From incisal and cervical regions of primary canines, two specimens were chosen randomly to investigate the dentinal tubules orientation in these regions by SEM.Results: SEM observations revealed that the dentinal tubules were oblique, both in incisal and cervical, so there was no difference in dentinal tubules orientation between these two regions. Mean microshear bond strength was 33.88±1:10.67 MPa for incisal and 28.79±11.72 Mpa for cervical region. Adhesive failure was the most predominant mode of failures being observed in both regions.Conclusion: There was no statistically significant difference in microshear bond strength of Clearfil SE Bond between the incisal and cervical dentin in primary tooth.