مجله دانشکده دندان پزشکی اصفهان
پیاپی 3-4 (پاییز و زمستان 1384)

In root canal therapy some accidents may happen that affects the prognosis of the tooth. For example, when preparing access cavity, perforation of furca is a possibility that leads to tooth loss. Important factors in prognosis of furcation perforation include: the kind of materials used, area that perforation has happened in, time in which perforation is sealed and skill of clinician. Because the kind of material used is important in control of inflammation and periodontal repair, we decided to compare effects of two materials Glass-ionomer and pro-root in this role. Methods and Materials: Thirty five teeth from one year old dogs were used in this research. It was an exprimental study and done in prof-M.Torabinejad dental research center. After anesthesia and injection of lidocaine, access cavity was prepared and root canals were cleaned by step-back technique and then filled.Furca was perforated by long burs of 3×3 mm. Areas were washed by serum to control bleed-ing.Perforated zones were sealed accidentally by pro-root and glass-ionomer and then the cavities filled by amalgam. Six teeth were considered as positive and negative controls. Two dogs were sacrifized after one month and two after two months by vital perfusion method. Jaws and teeth were seperated and put in formaline (10 percent). After laboratory procedures and preparing parafine blocks the samples were investigated by microscope. In this research we found that there is no important difference between two material after one and two months but in the same condition pro-root may cause more repair. Both glass-ionomer and pro-root will lead to repair of supporting tissues but inflammation near pro-root is less and periodontal regeneration, Cement & bone formation is more.

Pain after endodonic therapy, is of serious concern both to the dentist and patient. The aim of this study was to evaluate the effect of occlusal reduction on pain after endodontic instrumentation. Methods and Materials: In this matched clinical trial study, 98 patients were used. Each patient had a molar tooth requiring endodontic treatment. All teeth were vital, occlusion in contact and without preoperative pain or sensitivity to percussion. After access cavity preparation, teeth were divided into 2 groups: teeth with occlusion in contact and teeth with occlusal reduction. The teeth were instrumented using passive step back technique. Canals were dried and temporarily sealed. Each patient was informed and given a standard questionnaire form (Visual analogue scale). The patients recorded their degree of discomfort over a 48-h postoperative periods (0, 4, 8, 24, 32 and 48 h). Results were collected and tabulated using student t-test. There were no differences in the intensity of post operative pain between two groups in each periods of the study. Occlusal reduction in vital teeth and without preoperative pain or sensitivity to percussion cannot decrease postoperative pain effectively.

Diabetes increase salvia sugar and change its bacterial flora these changes destroy periodon-tal tissues. There are contravercies about affect of diabetes on periodontal tissues. In this study CPITN index that show intensity of periodontal damage was compared in insulin depended with healthy individual. Methods and Materials: In this study 132 CPITN index measured in 132 insulin depended diabetic patients and 132 healthy individual that two groups had similar oral hygiene. Thus CPITN index in diabetic patients compared with healthy individuals. There was no significant difference for CPITN index in male and female diabetic patients. CPITN index in diabetic patients was 1.36±1.24) and significantly higher than healthy individuals (0.54±0.77). Saliva change in diabetic patients and change in oral micro organism explins this subject. Effects of diabetes in oral cavity and periodontal issue can increase CPITN index in diabetic patients. These changes were not sex related.

Ditching and marginal defects of amalgam restorations can cause microleakage, recurrent carries, pulp hypersensitivity and finally loss of the tooth. The complete replacement of large restoration is time consuming, difficult and may potentially damage the pulp. Therefore in cases were there is no sings of recurrent caries, composite repair can be chosen as an alternative. The purpose of this study was to compare the effect of different bonding agent application on microleakage between flowable composite & amalgam. Methods and Materials: Standard calss V amalgam preparations were prepared on 60 carries free premolars and the cavities were filled using amalgam. After 24 hours, a 1 mm cavity on the occlusal margin of the class V restorations was prepared and specimens were divided randomly into four treatment groups: First group was filled with flowable composite and Single bond. Second group was filled with flowable composite and SE bond. Third group was filled with flowable composite and Prompt-L-pop. Fourth group Was filled with flowable composite without denting bonding agent. Specimens were thermocycled and sealed with fingernail polish except the composite-amlagam interface, then immersed in basic fuchsine for 24 hours. Specimens were sectioned and microleakage was assessed. The data were analyzed using Kruskal-Wallis test and Mann-Whitney U test. The results indicated that dentin bonding agent is effective in decreasing the degree of microleakage in amalgam-flowable composite interface and also the clearfil SE bond was more effective than Prompt-L-pop. But there was no significant statistical difference in microleakage between SE bond and Single bond. The application of dentin bonding agents in repair of amalgam retoration using flowable composite decreases microleakage but more researches should be performed.

Scientific development is essential for each type of development. The first step for planning is to know present situation. For planning to improve student role in research, we must know how much do they know about research methodology and what kind of attitude they have about it. The aim of this study was to determine Isfahan dental student's knowledge and attitude about research. Methods and Materials: All Isfahan dental school students (calss of 1999-2003) participated in this cross-sectional descriptive-qualitative study (n=300). Data was collected by self-administered questionnaire consisting of three parts: knowledge, attitude and demographic questions. The content validity of question-naire was confirmed by experts and its reliability by split half method. The face validity was also checked. The data were analyzed by SPSS-11 soft ware using frequency distribution and mean and correlation coefficient list. The mean mark of student's knowledge was 2.09±1.92 out of 10. Which would be increased with inereasing level of training and education. Ninty four persent of students would absulotely agree with necessity of participation in research activity during heir study period, 23.5 percent by increasing quality of services to the patient, 25.4 persent by increasing quality of study skills, 46.3 percent were in agreement with university support for research activity and only 15.1 percent of students believed that participating in research activity is wast of time. According to the results of this study, student's research knowledge is very low in spite of their attendance in research methodology workshops (40.5 persent). Because of their desire and positive attitude toward research activity, faculty officials should plan in more diciplined way, to improve the student's skills and knowledge.

Recurrent aphthous stomatitis is one of the most common Diseases of oral mucosa. In spite of its popularity and severity of pain, it dosent have a routine treatment method. Because of side effects of different chemical drugs, recently, herbal drugs had been used in treatment of these lesions causing a decrease in pain and burning. The purpose of this study was to evaluate the efficacy of persica mouth wash in controlling the pain and decreasing the healing period of Recurrent Aphthous Stomatitis (RAS). Methods and materials: In this double blinded clinical trial study, 24 patients with Recurrent Aphthous Stomatitis without any systemic Diseases were chosen. Each patient was considered as study sample for one time period and then as control for another time period. The patients used persica mouth wash and placebo (as mouth wash) alternatively. A visual Analogue scale (VAS) was used to evaluate the pain and burning of the lesions. For data analysis, chi square, t-test, and spss program was used. There was a significant difference in pain reduction (62.5 and 20.8 percent) and burning reduction (70.8 and 25 percent) between experimental and control groups. There was no significant difference in healing period reduction between the two groups. In this study persica mouth wash as a herbal drug had a positive effect on pain and Burning of the Aphthous lesions. This mouth wash was not effective in reducing the healing period of these lesions. This study suggests the use of persica mouthwash alone or in combination with other drugs to decrease pain and burning of Aphthous lesions.

Asthma is a common disorder that affects children. Only a limited number of studies have investigated the effect of asthma on dental caries. The purpose of this study was to determine the dental caries status in children with bronchial asthma. Methods and Materials: In this crossectional study, 75 asthmatic and 75 non asthmatic children who were matched according to age and sex were examined for dental caries. All children were four to Eighteen years old. The children were divided into four groups according to the severity of bronchial asthma as mild, moderate, Severe and intermittant asthma. They were also distributed according to the dental status as primary and permanent dentition and depending on the medication being used into inhaler, syrup, tablet and combination group. The data were analysed with Mann-Wintney and Kruscall-Wallis tests. A significant difference was found in DMFT between asthmatic group (2.27±2.65) and control group (0.8±1.41) but significant difference was found in DMFT between asthmatic (3.53±3.06) and control group (3.22±3.13). Mean of DMFT in asthmatic male was significantly more than the control group and also there was a significant difference in DMFT in children between 11-18 years old. There was no significant difference between asthmatic and control groups regarding severity of the disease, kind of drugs and the method the medication used. It was concluded that asthmatic children had higher caries prevalence in their permanent teeth, and the severity and the method of the mediaction being used had no effect on the dental caries in asthmatic children.

The mineral content of dentin increases with age and its primary structure is altered. These changes may have unknown effects on efficiency of adhesive systems. The aim of this study was to find the effect of aging on dentin bonding agents. Methods and Materials: fourty eight extracted human premolars were divided into 2 groups under 15 years old & 2 groups over 45 years old. After exposing surface dentin with wheel type burs and polishing dentin surface with paper disks, dental adhesives, Excite & Prompt L-Pop were used following manufacturer’s instructions. Then composite cylinders were bonded to dentin & light cured. Then Shear Bond Strength (SBS) of samples were measured with universal testing device (Dartec). Fractured specimens were observed under stereomicroscope to determine the type of fracture. The mean SBS for those teeth aged over 45 was 24.15 MPa using Prompt L-Pop, and 18.6 MPa using Excite, and for teeth aged under 15 years old was 21.5 MPa using Prompt L-Pop and 13.99 MPa using Excite. SBS of older teeth was shown to be more than younger teeth, also Prompt L-Pop showed higher SBS than excite. It seems that lower mineral content of dentin in younger teeth results in over demineraliza-tion while etching hence resin is unable to penetrate the collagens fibers resulting in voids in bonding area which reduces the SBS in this group. Also higher SBS of Prompt L-Pop can be explained by the water cone-tent of it, which serves as solvent while Excite has ethanol which is evaporated and reduces the penetration of resin.

Impression making is one of the most important steps in fixed prosthodontics. Due to contra-dictory opinions on the issue of the accuracy of silicone impression material as a function of technique, this study was carried out to assess the dimensional accuracy of master casts made by Rapid silicone material as a function of three impression techniques: with 2mm space, with 1mm space and without space for wash thickness. Methods and Materials: This experimental study was carried out by using laboratory models. Two dies (with and without undercut) served as laboratory models. 10 impressions were taken for each technique and stone models were poured. Six dimensions of 30 models (height and diameter for each die and distance between dies) were measured by digital caliper. The mean differences in measurements in stone model was compared with laboratory model. T-test and ANOVA analysis was used on statistical analysis. Impression techniques with different amount of thicknesses of wash impression material had statistical significant effect on dimensional accuracy of master models. Impression technique with 2mm of space for wash material compared to impression technique with 1mm space and without space for wash material was more preferable.

The human teeth have many anatomical variations and treatment of each tooth is under the influence of its configuration. Therefore, recognizing canal configuration is necessary for a correct endo-dontic therapy, and lack of information about canal configuration causes failure in therapy. Since one of the most effective factors on canal configuration is race, we planed to have an In vitro research in the city of the Isfahan. Methods and Materials: This study was descriptive, and was done on 160 extracted maxillary first premolars and mandibular second premolars, which were collected from a number of clinics and private offices in Isfahan. Teeth were decalicfied, injectetd with dye, and made transparent to determine the number of root canals and their type. Finally, the teeth were cut in cross sections in three points of the root and canal configurations of teeth were evaluated. The specimens were classified according to Weine system by naked eye. In clearing Method, from 80 total sample sizes, most of them were type III (67.5 percent). Mandibular second premolars, from 80 total sample sizes, most of them were type I (91.25 percent). In sectional methods, from 80 total sample sizes, most of them were type III (70 percent) and frome mandibular second premolars, from 80 total sample sizes, most of them were type I (88/75 percent). In other countries many researches have been done using different methods about internal anatomy of teeth and the results are different form this study. It appears that the differences are due to genetic or race factors and methods used. Additionally, results of different studies indicate that more attention should be given to studies on canal configuration of these teeth.

Current data indicates that the risk of transmilssion of blood-borne pathogens in dental health care settings is low. Pre-exposure hepatitis B vaccination and the use of standard precautions to prevent exposure to blood are the most effective strategies for preventing DHCP from occupational infection with HIV, HBV or HCV. Dental health care facility should develop a comprehensive written program for preventing and managing occupational exposures to blood that, describes types of blood exposures that may place DHCP at risk for infection, outlines procedures for promptly reporting and evaluating such exposures, and identifies a health care professional who is qualified to provide counseling and perform all medical evaluations and procedures in accordance with the most current USPHS recommendations. Finally, resources should be available that permit rapid access to clinical care, testing, counseling, and PEP for exposed DHCP and testing and counseling of patients.