JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)
Year:2002 | Volume:14 | Issue:4 (39)|Papers Count:11

The purpose of this study was in vitro evaluation of shear bond strength of different bonding agents (single bond, scotch bond multi purpose, etch & prime, excite, syntac, margin bond) on human enamel and dentin.The adhesive agent was on 30 flat preparations made on facial and lingual surfaces of extracted teeth. The experimental teeth were randomly divided in six groups of five samples each.Group 1: Single bond 2: Scotch bond multi pursose. 3: Etch & prime. 4: Excite 5: Syntac 6: Margin bond. 1st and 4th bonding agents are one bottle, 2nd and 5th are multi step agents and 3rd one is self etching primer. The enamel surfaces were etch (except etch & primer) and were applied bonding agents following the manufactures' instructions and were cured.The adhesive agents (except margin bond) were tested on 50 flat too. The experimental teeth were randomly divided in five groups of ten samples. The dentin surfaces were treated by bonding agents and cured like the way that said.Cylindrical composite were placed on the enamel and dentin surfaces by mold then samples 1000 times thermocycled after that they were placed in the cylinidrical self-cure acrylic. Shear resin bond strength of samples were determined by instron machine. One way ANOV A revealed no significant differences among the six groups of enamel (P<0.05). Kruskul wallis test revealed no significant differences among the five groups of d~ntin (P<0.05). Mean shear bond strength were 19 Mpa To 28.5 Mpa in the 'enamel surfaces. Mean shear bond strength, was 18.4 Mpa to 22.5 Mpa in the dentin surfaces. In the enamel groups' single bond produced the highest bond and margin bond produced the lowest bond. In dentin groups syntac produced the highest bond and single bond produced the lowest bond.

Rampant caries is a type of dental caries and children with this disease suffer much pain and problems. Because of the protective role of saliva that may be impaired in these children, relation between the saliva and rampant caries is determined. For this purpose the paraffin-wax stimulated whole saliva was estimated in 117 physically healthy children aged.4-5 yr that have deciduous dentition. Children were categorize in three groups. First with rampant caries (Case), second, with average DMFT (Control) and third caries-free children (Control 2). Each group composed 39 children. The rate of flow was determined during sample collection. Calcium, phosphate, PH, and buffering capacity of samples were analysed biochemically. The results were analysed with ANOVA.The rate of flow, PH & buffering capacity of samples from children involved with rampant caries were lower than control groups. t-lest for the differences between groups were statistically significant only for PH & salivary rate of flow (p<0.05). The mean levels of both Calcium and Phosphate in saliva were higher in children with rampant caries but only for phosphate differences reached statistical significancy (P<0.05).Although it seems that there is some personal differences in saliva which lead to rampant caries but more studies in this topic are required.

Pulp and periapical diseases are directly or indirectly caused by oral bacteria and various bacteria species play role in root canal infection. The purpose of this study was to investigate bacterial flora in the apical third of teeth with periapical lesion.Forthy teeth with periapical lesion from 40 patients, extracted. Five mm of the apex of each teeth was cut under anerobic condition using sterile bur. The content of root canals were transferred to two blood agar cultures including an aerobic and anerobic (Hydrogen 5%, CO2 10% Nitrogen 85%) condition using sterile files.Ten intact teeth extracted dueto orthdontic treatments as control group. After the formation of colonies, the types of bacterial species were recognized according to morphologic properties of cultured colonies, gram staining technique and using microscope and biochemical tests.The results showed that 126 bacteria belonging to 17 different species were isolated 62 bacteria from 126 bacteria were obligate anerobic and the sum of obligate and factitive anerobic bacteria were 118 in number (94%). Almost all the specimens (39 out of 40) showed bacterial growth and at least one anerobic bacterium species was detected in each of them. This confirms that the root canal infections are caused by various species. Sterptococcus species were the most common strain, bacteroid species which the peptococcous were the most common.At least 26 specimens (95% of all spescimens) had a strain of bacteroid in root canal infection.Based on the results of this study, bacteria play a very important role in root canal intection and our study indicated that anerobic bacteria had the most efficacy.

The necessity of vitality pulp testing in the diagnosis of pulpal diseases and differentiate it with other diseases is always emphasized.Since it is not possible to evaluate pulpal tissue directly, and the histological state of the pulp cannot be detected by the clinical state of it, the dentist must estimate the status of pulp indirectly by means of gathering data about patient's history, clinical observations and diagnostic tests. Diagnostic tests, however, have limitations so that the accuracy of the results of those tests is influenced by them. Therefore it seems necessary to do more evaluation about the validity and reliability of these teste.The aim of the present study is the evaluation of the accuracy and the reliability of cold test (ethlycloride), heat test (warmed burnisher), percussion test and electric pulp testing in assessing pulpal vitality. For this, 100 teeth of 62 patients with the chief complaint of pain due to caries / trauma and old restoration were evczd [9780u8] aluated and the responses of the patients (TP/TNIFPIFN) were used for the calculation of 7 diagnostic tests, characteristics (Sensitivity, Specificity, positive &The following results were concluded1. The best test in rolling in the disease is percussion test, and heat test, cold test and EPT are in next orders.2. The best test in rolling in the disease is percussion test, and EPT, cold test, heat test, are in next orders.3. The most accurate test is percussion test (98%) and cold test and heat test (89%) and EPT are in next orders.Based on the above results, it seems necessary to use these tests simultaneously and to interpreter the result of each test based on the results of the other tests.

Dental plaque is an etiologic factor in periodontal disease and dental decay. Therefore plaque control is so important in preventive of oral diseases. Mechanical plaque control is the best way for removal of dental plaque. In this clinical trial study Rolling and Modified Bass methods compare with tooth brushing time (3, 5 min) without any methods.60 dental students selected for this study 30 of them in grade 1 without any training about the tooth brushing methods and another 30 of them in last grade that know about the methods very well.After plaque accumulation all the students divided in four groups. In first group Rolling method used in second group M. Bass method and in third group 3 minutes tooth brushing without any method and in forth group 5 minutes. After tooth brushing plaque index recorded.There is no difference in Rolling-M. Bass and 5 min. in plaque removal But M. Bass is more efficient for plaque removal than 3. min.For people that are not educationable we can advise them the brushing '. time to be at least 5 minutes.

Major thalassemia is associated with pronounced disorders in craniofacial area. By anthropometric technique, we can be informed from these disorders. The aim of this study is evaluation of cranio'tacial dimensions in patients and the comparison between them and normals.98 major thalassemic patients (46 boys and 52 girls) with 17-21 years old in Isfahan center of thalassemia by sampling method were selected. anthropometric dimensions measured with digital caliper with 0.01-mm precision. These datas were analyzed with SPSS software and t-student analysis. In major thalassemic boys Bizygomatic and intercanthal distance and upper lip vermilion and stomion-Gnathion distance are bigger than normal’s. In major thalassemic gils, Inter canthal and bizygomatic and. upper lip vermilion distances and mandibular height and lower face height are bigger, than normal’s. Thus major thalassemia produces apparent malformations in craniofacial area especially in cancellous bones.

With due attention to incidence of impacted third molars and need to surgical remove of these teeth, patients suffered from some of edema, pain and trismus. The purpose of this study is comparison of effect of povidone-iodine and chlorhexidine oral rinse together and with normal salin to reduce trismus and edema. 60 Patient select and devided on three groups randomly. Patients of each group gragled one of these oral rinses before surgery. edema and trismus were measured upon all patients.After statistical analysis it was defined chlorhexidine reduces-trismus and edema rather than povidone-iodine and normal saline. It was significant difference statistically.

The aim of this research was deteramine the epidemiology of current prosthesis in the population of Tehran province in year 1996. 720 Samples (377 female and 343 male) form age groups 11 (15-19). III (35-44), and IV (65-74) based on randomized cluster sampling using a systematic selection and standards the WHO organization.The research uses deserciptive and lytic method based on observation and interview research techniques. Result show that 22.5% of the female and 23.9% of male had mandibular prostheses and 25.7% of the female and 24.5% of the had maxillary prosthesis. An age increases the number of people using prothesis increases. The percentage of people with maxillary prothesis was more than mandibular prothesis.