JOURNAL OF RESEARCH IN MEDICAL SCIENCES (JRMS)
Year:2000 | Volume:5 | Issue:3|Papers Count:18

Introduction. Among different technics of decidous tooth pulpotomy the best method would be more suitable which has high grade of successful in long term and simple usage for child and dentist and also have at least side effects. In this research two methods pulpotomy of molar tooth have been compared by ferric sulfate 15.5 percent and tricresoformalin.Methods. In this study 58 decidous molar tooth treated by ferric sulfate 15.5 percent and 59 deciduous molar tooth same patient by tricresoformalin. After 6 and 12 months of treated, the clinical and radiographic sign and symptoms registered and he results fo two method by statistic test evaluated. Results. Success rate of clinical and radiographic by ferric dulfate have been 94.8 percent and formocresol 98.3 percent after 12 month of treated. The differences the success rate of two method were not significant.Discussion. The method of molar decidous tooth pulpotomy by ferric sulfate would be replacement of formaldehyde derivate if this results would be use in long term and greater sample size study.

Introduction. In some area of our country for example: Bushehre, some parts of Hormozgan, Yazd, Azarbayjan provinces, the levels of fIouride in drinking water is over optimom level. So because of this reason the incidence of flourosis in these areas is high. Determination of dental flourosis in four areas of Najafabad, Filor, Joozdan and Rahmatabad with different levels of flourosis with DMFT index is the aim of this study. Methods. This study is a cross sectional study. Samples have been selected by simple accidental manner. 254 school children aged 7-12 years old in four different areas have been examined which all of them have been lived in same areas from birth so far. To collect the necessary information, a checklist was prepared. It was contained demographic information, the intensity of flourosis of Dean classification, DMFT index on base on WHO.Results. The levels of drinking water fluoride of four areas determined which 0.23ppm Najafabad, 0.6ppm Joozdan, 1.35ppm Rahmatabad and 0.78ppm Filor. Also the intensity of flourosis on base of Dean classification have been: 15.5 percent normal sitution, 23.2 percent questionable, 31.1 percent very mild, 19.3 percent mild. 6.7 percent moderate, 4.7 percent severe. DMFT index have been 6.6 in Najafabad, 3.37 in Filor, 5.51 in Joozdan and 3.13 in Rahmatabad. Increasing of dental flourosis in persons who using drinking water observed. There was direct relationship between the drinking water containing flouride and incidence of flourosis. The relationship between of average DMF and fluoride in drinking water of Filor and Rahmatabad with Najafabad and Joozdan showes significant differences.Discussion. The results shows that flourosis observe in four areas. The mean of DMF with different levels of fluoride in drinking water are different. Most of necessary fluoride for body could be earned by drinking water, so low lavel incidence of DMF in school children in areas with high fluoride had showed.

Introduction. One of the problems encounted in endodontic treatment is the treatment of vital open apex teeth. Among different materials used for this purpose, Calcium hydroxide is the most widly used material. The purpose of this study was to compare a newly introduced material called MTA (Mineral Trioxide Aggregate) with calcium hydroxide in apexogenesis procedure.Methods: Fourty open apex canine teeth of 10 young cats were used in this study. Crowns of the teeth were resected and access cavities were slightly extended. Floor of pulp chamber of 16 teeth were packed with MTA and that of the other 16 teeth with Ca(OH)2.Access cavities were double sealed using ZOE and Amalgam. After 4-6 months the animals were sacrificed and the pulp and periodical tissues were examined by histologic evaluation. Four intact teeth were also used as negative control and 4 teeth without coronal seal were used as positive control.Results. Radiographic evaluation of MTA treated teeth after six months indicated that the apex of all of the teeth were closed and no calcified bridge was observed. In contrast, the apex of 13 out of 16 teeth treated with Ca(OH)2 had been closed and in calcium hydroxide samples calcified bridge had been formed. Histologically, there was a significant difference in microscopic changes of the pulp between the two treatment groups (P<0.05). The pulp of the teeth with MTA was similar to that of a normal teeth and they showed no calcified bridge. Furthermore, histologic investigation of the periapical area showed no statistically significant difference between the two groups.Discussion: Based on the results obtained in this study and the previous findings despite the fact that Ca(OH)2 may result in the apical closure because MTA causes less pulpal changes in apexogenesis need MTA treated teeth may not further root canal therapy. Therefore, MTA application is superior to Ca(OH)2 for apexogenesis procedures.

Introduction. The purpose of this study is measurement the stresses due to matrix bond and their effect on fracture or crock formation in teeth and finally modifying in treatment methods of tooth.Methods. We use a second premolar that was as similar as measurements of wheelers studies. Au mod cavity prepared with buccolingual width 3mm while the roof of pulp chamber has been removed and gingival floor was 1mm higher than CEJ. CTS was prepared in three dimention: crolan, sigital and axial and then tooth model was made based on Nisall program. The forces due to matrix band measured by strain guage and then, this force based on finite element method applied on the prepared model. Results: Inall cases, stresses observed in tensile and shear from tensile stresses was mainly in cervical one third of buccal cups and shear stress was surronded cervical area of the tooth like as circle. The greatest amount of forces were localized in gingival floor in mesial area and in the enamel with increasing the depth and sidth of cavity. The amount of this stresses increased especially in increasing of depth. With increasing the width and depth cuspal displacment was observed especially in colossal on third which localized in buccal cusp.Discussion. Matrix band stresses mainly are destructive and cause fractures or at least crack formation in tooth. So its preffered to use thinner band in shorter time as much as possible. using of anatomic bands were prefeved.

Introduction. The maxillary first premolars have two canals wich can be used for prefabricated posts. In this study we compared the fracture resistance of amalgam buuild-up restorations after using this kind of posts in coch of these canals. Methods. Prefabricated posts were used in two groups in maxillary first premolars: one group in buccal and the other in palatal canal. After complate amalgam restoration usinf on INSTRON machine the fracture resistance were determined. Analysis of results and failure mode of each groups were performed.Results. There was no statistical significant difference in fracture resistance in two groups. There was significant difference in failure mode in groups. Discussion. All the fractures were in the restorative material and in palatal cusp so in choosing a canal for prefabricated post precedures the amount of missed coronal structure and all clinical factors are important factors.

Introduction. Occasionally over exposure or over development makes processed radiographs too dark, By reducing (Bleaching) such a radiograph whit a reducing solution the dentist can enhance the image with low diagnostic value. Methods. Mandible of a dry skull with posterior teeth, double films pocket, intera oral radiography unit, diluted solution of fixer and developer, Coppor sulfate reducer solution, automatic processing unit. A radiograph was prepared with normal exposure time from posterior region of mandibule and saved as positive control. A series of double film pocket were exposed to obtian overexposed radiographs. One film from each pocket was used as the negative control and the other was reduced by copper sulfate solution. The diagnostic quality of reduced radiographs were evaluatel in three steps: 1. By clinical evaluation of reduced radiographs. 2. By densitometry of reduced radiographs. 3. By evaluation the number of steps wedges.Results. The diagnostic quality and resolution of reduced Radiographs were increased and their contrast was decreased.Discussion. Copper sulfate reducing agent is very good solution for improving diagnostic quality of very dark radiograph and prevent reexposure of the patient.

Introduction. For diagnosis and treatment planing and detection the quality of remaining Alveolar bone the radiography is very useful so the type of radiography is very important. The purpose of this study is the comparison between panoramic, periapical (bisecting technique) and vertical bitewing radiographs in diagnosis of periodontitis. Methods. Twelve patients (3 male and 9 female) with a mean age of 35, with a moderate to advanced periodontitis were evaluated. At the time of periodontal surgery, in the posterior site of two jaws (in 6 and 7 teeth), the bone loss was measured from CEJ to the base of alveolar bone, and compared with the radiographic findings of proximal bone loss.Results. The average of distance between CEJ and alveolar bone in 48 surfaces were 4.27 in clinic, 4.80 in panoramic, 2.62 in periapical (bisecting technique), 2.98 in vertical bitewing and 4.05 in panoramic without magnification.Discussion. In this research we cancluded that both techniques (periapical and vertical bitewing) are not accurate in detection of proximal bone loss and there was significant difference between quantity of proximal bone in clinical measurment than radiographic measurment and this study showed that the panoramic (specially panoramic without magnification) is more careful than other radiographic techniques in detection of proximal bone loss.

Introduction. The ANB angle has been recognized as a skeletal sagittal discrepancy indicator and has become the most commonly used measurement since that time. It seems this angle is affected by several factors other than the anteroposterior position of maxilla and mandible.Methods. Tracing on lateral cephalometry films was done for 110 untreated cases with class I, II, III malocclusions. regression analysis was used to describe the proportion of the distorting factors caused by usual changes in the cranial and facial skeleton. Results. ANB mean differences between malocclusion groups was significant. Regression analysis between ANB, SN/MP and SNA angles in all groups was significant. The highest coefficient of determination was found in class I sample and the lowest was found in class II sample.Discussion. The results revealed that another factors can influence of ANB angle. These factors are rotation of SN plane, the length of the SN and rotation of jaws. Thus the use of normal range for ANB angle in determination of sagittal position of maxilla and mandible is incorrect and it must substitute with accurate parameters.

Introduction: The purpose of this invitro investigation was to compare the anti-bacterial effect of normal saline and sodium hypochlorite (5.25 percent and 0.5 percent) with calcium hydroxide used as intra canal dressing used in different time periods. Methods: 180 single-rooted freshly extracted teeth were selected. The crowns were resected of CEJ and the canal were flared to the same length using a number one Gates-Glidden. A suspension of selected strict and facultative anaerobic bacteria was placed inside the canals and incubated in anaerobic condition for 24 hours. Then the teeth were randomly assigned to 9 groups.Results: Group 1. Negative control; group 2. Positive control; group 3. instrumented using normal saile; group 4. instrumented using 0.5 percent sodium hypochlorite; grooup 5. instrumentation using 5.25 percent sodium hypochlorite; group 6. After instrumentation, 10 min. of calcium hydroxide was placed; group 7. after instrumentation 24h of calcium hydroxide was placed; group 8. After instrumentation 48h of calcium hydroxide was placed; group9. After instrumentation a week of calcium hydroxide was placed. Then paper points were used to get samples in each group. The samples incubated in anaerobid condition for 48 hours. The TSB turbidity was compared to mcfarland"s scale.Discussion: The results of this study indicates: Sodium hypochlorite in both concentrations were significantly more effective than normal saline. The one week calcium hydroxide group was significantly more effective than all other groups and was comparable to negative control group. The 24h and 48h calcium hydroxide groups did not have significant differences with each other or with the sodium hypochlorite groups. The 10 min. calcium hydroxide group was only comparable to normal saline group.

Introduction. In patients with anterior open bite, wether with skeletal factors, or with dental factors, the excessive eruption of posterior teeth, is one of the specific findings, and this excessive eruption causes the backward and downward rotation of mandible, which results in an increase in lower facial height and steep mandibular plane. In these patients, depressing of posterior teeth is the ideal treatment and to achieve this goal is one of the most difficult tooth movements for orthodontist. Methods. For this purpose, a removable appliance was designed and to evaluate its eficacy, six patients were selected, four of them were in permanent dentition and two in mixed dentition period. They were under treatment with this appliance, full time for three to three and a half months. Before starting treatment, lateral cephalometric radiograph and study casts were prepared and the above mentioned period were repeated. The amount of bite closure was measured by comparing study casts before and after treatment. Also cephalometric changes were evaluated by comparing pre-and-post treatment records.Results. As a result average of maxillary first molar intrusion was 1.1 mm and average of mandibular first molar intrusion was 1.3 mm , which had resulted in upward and forward rotation of the mandible. The average changes due to mandibular rotation were: The amount of bite closure 3.7mm; Decrease in lower facial height 3mm; Prominence of chin 3.2 mm; Decrease in mandibular plane angle 2.3; Decrease in y-axis angle 2; Increase in facial angle 2.3.Discussion. Therefore it is obvious that clinically the suggested appliance is capable of, intruding posterior teeth in both of maxilla and mandible and then due to upward and forward rotation of the mandible, the steep mandibular plane and lower facial height are decreased. Now according to the results of this investigation can be highly hopefull that, the number of patients who need orthographic surgery, for correction of anterior open bite to be diminished.

Introduction. Dental stones are widely used in dentistry and the success or failure of many dental treatments depend on the accuracy of these gypsums. The purpose of this study was the evaluation of Iranian dental stones and comparison between Iranian and foreign ones. In this investigation, consistency and setting time were compared between Pars Dendn, Almas and Hinrizit stones. The latter is accepted by ADA (American Dental Association). Consistency and setting time are 2 of 5 properties that are necessitated by both ADA specification No. 25 and Iranian Standard Organization specification No. 2569 for evaluation of dental stones.Methods. In this study, the number and preparation of specimens and test conditions were done according to the ADA specification No. 25 and all the measurements were done with vicat apparatus. Results. The results of this study showed that the standard consistency of Almas stone was obtained by 42ml water and 100gr powder and the setting time of this stone was 11±0.03 min. Which was with in the limits of ADA specification (12±4 min). The standard consistency of Pars Dandan stone was obrianed by 31ml water and 100 gr powder, but the setting time of this stone was 5± 0.16 min which was nt within the limits of ADA specification.Discussion: Comparison of Iranian and Hinrizit stones properties showed that two probable problems of Iranian stones are:1- Unhemogrnousity of Iranian stoned powder was caused by uncontrolled temperature, pressure and humidity in the production process of stone.2- Impurities such as sodium chloride was responsible fo shortening of Pars Dendens setting time.

Introduction. The optimum amount of fluoride in drinking water has been determined 1ppm for special areas by WHO. In jarghoyeh the amount of fluoride in drinking water is less than optimum, but dental fluorosis has been observed in a great deal. The purpose of this comparative study is to determine the prevalence of dental fluorosis and the mean DMFT values and their relationship among guidance school students in Jarghoyeh Olya and Jarghoyeh Sofia. Methods. The main reason of this research was to compare fluorosis prevalence in Jarghoyeh Sofia and Jarghoyeh Olya. A pilot study was carried out and 191 person for the number of specimen was determined. Since DMFT was also to be investigated, the number of specimen was incresed., Finally 256 guaidance school students in Jarghoyeh Sofia and 263 students in Jarghoyeh Olya were selected by sharing method. The DMFT and TF indices, respectively, were used to asses dental caries and dental fluorosis.Results. The prevalence of dental fluorosis in Jarghoyeh Olya was 65.8 percent and in Jarghoyeh Sofia was 44.9 percent. The mean DMFT indices in these two regions were 2.2471 and 2.0508 respectively. Evaluation of amounts of DMFT in different scores of TF index, shows that from zero score to 1 score, DMFT decreases. Then it gradually increases and as a result in 5≤ score it reaches to the highest level.Discussion. Factors such as hot climate and salty drinking water causes the inhabitants to drink more water. Also they drink tea a lot. Thus in spite of the low fluoride content of drinking water, prevalence of dental fluorosis was high. During tooth mineralization, fluoride reacts with hydroxyapatite crystals and produces fluorohydroxyapatite, resulting in higher resistance to tooth caries. On the other hand, absorption of excessive fluoride, results in disorder of formation of enamel. This leads to a hypoplastic and porose enamal. This enamel has lower resistance to caries and higher potential to absorb dental plaque. Maybe this is the reason of decreasing the caries prevalence in low degrees of fluorosis and increasing of caries prevalence in high degrees of fluorosis in this research.

Introduction. Glass ionomer materials have been, used for years as liners, bases and temporary restoration for children. Their bonding properties allow temporization, which would be difficult with conventional cements of restorative materials. The desirable properties include easy and rapid application, fluoride release, biocompatibility and adhesion to dentin and enamel tend to be used in children specially for precooperative or handicapped children and preclude the need for treatment using general anesthesia of sedation in this research, shear bond strength of glass ionomer in two groups, including normal group and hypoplastic enamel group is tested. Methods. For this purpose, 2 groups each including 12 samples of normal anterior deciduous teeth and hypoplastic anterior deciduous teeth (with attention to hypoplastic indices) were chosen. The labial surface of teeth were prepared with medium and fine size discs, chem fil glass ionomer cement was bonded to prepared surfaces of teeth, and then samples were fixed in special site of self curing acrylic. The specimens were tested with a model 4031 instron machine. A shear load was applied to the base of the bonded glass ionomer cylinder with a knife edge rod (width, 0.5 mm) at a cross head speed of 0.5 mm/mm.Results. The mean of obtained sbs for 2 groups was 16.35 and 11.63 KGF/mm2.Conclusions. Statistical analysis of the results showed significant defferences between studied groups. But with attention to desirable properties, application of glass ionomer cement in hypoplastic defects of enamel in children is recommended.

Introduction. Endodontic implants are used to ratain teeth with periodontal bone resorption and/or short roots. The implants are placed from inside of root canal passing the apex into the periapical bone. Teeth with horizontal root fracture. Clinically mobile teeth, teeth with periodontal bone resorption, teeth with reduced root / crown ratio. Anatomic considerations around the root apex. Methods: After case selection, twenty five endodontic implants were placed in selected teeth. The cromcobalt and/or titanium implants were placed using Frank"s method.Results. After three years of radiographic evaluation, 3 of the cases failed and the rest of the samples were completely normal. The success rate was 88 percent.Discussion. Endodontic implants allow us to treat teeth with mobility due to root fracture, bone resorption, of reduced crown / root ratio. The success rate in this investigation was 88 percent which was comparable to 91 percent success rate in the similar research. Regarding the success rate of investigations of endo implants, this method is a acceptable preventive treatment to retain mobile teeth.