Antibacterial substantivity of three concentrations of doxycycline on bovine root dentin infections: an in vitro study

The aim of this in vitro study was to compare the antimicrobial activity and substantivity of three concentrations of doxycycline on bovine root dentin infections. Seventy dentin tubes prepared from intact bovine incisors were infected in vitro for 14 days with Enterococcus faecalis. The specimens were divided into five groups according to the used intracanal irrigation as follows: Group 1: l00mg/ml of doxycycline hydrochloride solution [DHS] [n=20]; Group 2: 50mg/ml of DBS [n=20]; Group 3: l0mg/ml of DHS [n=20]; Group 4: positive control [infected dentin tubes] [n=10]; and Group 5: sterile saline [negative control] [n=10]. Dentin chips were removed from the canals with sequential sterile low - speed round burs with increasing diameters of ISO sizes: 025, 027, 029, 031, and 033 at experimental times of 0, 7, 14, 21, and 28 days. After culturing, the numbers of colony-forming units [CPUs] were counted. Data were analyzed using analysis of variance and covariance with repeated measures [ANOVA] to indicate differences between the experimental groups and the positive control. One-way ANOVA [Tukey's method] was used to indicate differences within each layer. The numbers of CFt/s in aJJ three experimental groups were minimum in first cultures, and the obtained results were significantly different from each other at any time period [P<0.05]. In first culture, the groups 1 [0.400 +/- 0.699] and 3 [4.700 +/- 3.683] showed the lowest and highest numbers of CPUs, respectively. In each group, the numbers of CPUs increased significantly by time lapse [P < 0.05]. Under the conditions of this study, it can be concluded that doxycycline HC1 may be useful as a substantive antimicrobial agent

Comparison between the accuracy of digital and conventional radiographies for evaluation of the curved canals length

Proper cleaning and shaping of the root canal system is one of the most important aspects of endodontic therapy. To estimate the canal length before instrumentation in endodontic treatment, traditionally, conventional radiographic techniques and, recently, Direct Digital Radiography [DDR] are applied. The application of computer technology in radiography has allowed less exposure time for image acquisition, better storage and retrieval, and transmission to remote sites in a digital format, elimination of processing, and a considerable time saving. The purpose of this study was to compare the accuracy of DDR and conventional radiography in determination of working lengths of curved canals in first mandibular molars. Forty extracted human first mandibular molars with root curvature were selected. Samples were divided into two groups: With root curvatures less and more than 25[o]. The samples were mounted in plaster blocks and their canal lengths were estimated by using DDR and conventional radiographs. Regression analysis, correlation coefficient, and t test were used for statistical analysis. In spite of the greater accuracy of conventional radiography in canals with curvature <25[o] and the greater accuracy of digital radiography in canals with curvature >25[o], the differences were not statistically significant. Both conventional radiographs and DDR can be used to determine working length during endodontic therapy

[Comparison of the accuracy of panoramic radiography, coronal and axial CT scan in diagnosis of mandibular fractures]

Mandibular fracture is the most common facial bone fracture due to facial trauma. A variety of imagings have been used for diagnosis of mandibular fractures. However, the choice of imaging for diagnosis of mandibular fractures is controversial.Present study compares the accuracy of the three most common imaging methods in mandibular fracture diagnosis; panoramic radiography, coronal CT and axial CT scan. This cross sectional diagnostic study was performed on 45 patients with a clinical diagnosis of post traumatic mandibular fracture at the ENT department of Shaheed Sadoughi hospital,Yazd. Patients underwent panoramic radiography and CT scan [both axial and coronal]. Then, all were operated for reduction of fracture [either closed or open] and fixation done with arch bar and MMF in combination with or without rigid internal fixation. The physical examination and observation during operation was considered as the exact diagnosis. The radiological findings were reported by three different radiologists. Finally, the accuracy and sensitivity of each method was compared with the other methods. There was no significant difference between the accuracy of panoramic radiography and coronal CT scan in all of the regions, but the accuracy of axial CT was significantly less than coronal CT in certain regions. The accuracy of panoramic radiography and coronal CT scan in diagnosis of mandibular fractures is the same or higher than axial CT scan. Additionally, panoramic radiography is more accessible and less expensive than coronal CT scan. Therefore, this study recommends oral panoramic radiography as the first radiologic test for diagnosis and localization of mandibular fracture

[Efficacy of miswak [salvadorapersica] in prevention of dental caries]

The rate of tooth decay and periodontal diseases today is still high, regardless of progress in oral and dental hygiene. The traditional toothbrush or chewing stick called [Miswak] has been used since ancient times. Many significant effects of Miswak such as antibacterial, anti-caries and antiperiopathic effects have been recognized today. Tooth care is a very important issue and both prevention and treatment of dental caries could be very helpful in maintaining good personal health. In this research, the efficacy of natural toothbrush or Miswak in prevention of dental caries was investigated and compared with the efficacy of ordinary toothbrush and toothpaste. Miswak was introduced for preventing dental caries by the Holy Prophet Mohammad [S.A.W] 1400 years ago and has been used since then in many Islamic countries. In this research, the efficacy of Miswak in prevention of dental caries was investigated and compared with the efficacy of ordinary toothbrush. This analytical and clinical trial was performed in a high school student population [girls and boys] in the city of Yazd, Iran in 2001-2002. Twelve high schools were randomly chosen. From these high schools, 380 second year students [190 cases and 190 controls] were enrolled and their teeth condition such as the number of decayed, missing and filled teeth [DMF] were recorded in a specific questionnaire. The degrees of decay in the decayed teeth were recorded as well. Then, Miswak sticks were distributed to the case group and required dental training was given to both groups. After one year, the examinations were repeated and findings recorded in the same questionnaires. For analyzing the data, one-way variance analysis, Chi square, Paired t-test and two variable analyses were used. At the start of the study, there were no significant differences between the two groups [case and control] with regards to their dental condition and the frequency of brushing of their teeth [p-value=0.162]. In addition, there were no significant differences in DMF between the two groups. The prevalence of dental caries was slightly less in the control group [0.89 times of this in the case group]. The data collected at the end of the study showed a significant increase in DMF in the control group [P-value=0.000]. There was a 55% increase in the rate of dental caries in the control group as compared to the case group [0.89 before the study and 1.38 after the study]. The risk of dental caries for each tooth in the control group was 9.35 times more than the case group [9.14% and 0.98% respectively]. Despite the same training and similar intention in brushing of teeth and the same dental situation in two groups at the start of the study, rate of dental caries which was primarily more in the case group in the beginning was lesser than the control group at the end of this study. This might be as a result of the antimicrobial effects of Miswac. A study with more cases and longer time period is needed to prove this suggestion. Our data shows the need to encourage the use of Miswac in the general population, especially in developing countries for its effectiveness in the prevention of progress of dental caries

[Evaluation of changes in the mandibular angular cortex using panoramic images in over 20 years old women [2001-02]]

Osteoporosis is a major problem of the elderly, especially in post menopausal women. Aim of this study was to evaluate bone resorption [BR] in women older than 20 years. One hundred women were assessed using an anatomic landmark of mandible [i.e. thickness of mandibular angular cortex, TMAC]. Results showed that BR had a positive significant relation with age and multiple pregnancies, and a negative relation with the level of education [p<0.001]. BR in menopausal women was significantly higher than that in women of reproductive age [1.83 + 0.81 and 3.13 + 1.4,p<0.0001, respectively]. Also, women with history of backaches had higher BR than women without backaches [1.58 + 0.54 and 3.08 + 1.4, p<0.0001, respectively]. From these results, it could be concluded that thickness of mandibular angular cortex can be used as an index for BR

[Radiological evaluation of temporomanditoular joint changes in asymptomatic 20-50 years old patient in Yazd Iran]

Radiographs are valuable in the investigation of temporomandibular joint [TMJ] pathogenesis. Despite extensive and detailed description of the various pathologic states that may involve the joint, scant attention has been paid to the appearance of the normal joint. This is an important omission since it is clear from both skeletal and histological studies that a continuous process of remodeling occurs in all joints throughout adult life. The purpose of this study was to determine the rate of bony condylar changes of the TM joint in asymptomatic adults aged between 20-50 years referring to the radiology department. A total of 160 condyles of 80 asymptomatic patients were studied. Patients who had lost more than two teeth in either jaw were excluded. The effect of age on the variation was also analyzed. Standard panoramic jaw radiography [plan meca EC 2000 PM] was obtained for all patients. Each joint was evaluated in random order. The age of the patients was between 20-50 years and they were divided into three groups accordingly. In our study, about 75% of the patients showed osseous changes in at least one condyle. Flattening was the most common change [about 65.3%] followed by osteophytes [33.3%], sclerosis [32.1%] and concavity [28.4%]. Sub cortical cysts and erosion were relatively rare findings. Radiographic appearances of asymptomatic temporomandibular joints vary widely and remodeling changes are commonly seen. Age can be associated with osseous changes, but these relationship are not direct or mutually exclusive

[Comparison of the accuracy of digital and conventional radiography in evaluation of curved canals lengths]

Proper shaping and cleaning of the root canal system is one of the most important aspects of endodontic treatment. To estimate the canal length before instrumentation in endodontic treatment, traditionally, conventional radiographic techniques and recently Direct Digital Radiography [DDR] are applied. The application of computer technology to radiography has allowed less exposure time, image acquisition, manipulation, storage, retrieval, and transmission to remote sites in a digital format, elimination of wet processing and considerable reduction in the time lapse between image acquisition and display. The purpose of this study was to compare the accuracy of DDR versus conventional radiography in estimating endodontic file lengths of curved canals in first mandibular molars. In this test evaluation study, fourty extracted human first mandibular molars with root curvature were selected. Samples were divided into two groups: With root. Samples were mounted in plaster and more than 25 curvature less than 25 blocks and canal lengths were estimated by using DDR and conventional radiographs. Regression analysis and correlation coefficient were used to calculate statistical differences between the groups with P<0.05 as the limit of significance. Conventional radiography was more precise in canals with less than 25 degrees curvature [P=0.160]. While, DDR was more precise for canals with curvature more than 25 degrees [P=0.605]. However, these differences were not statistically significant. The image quality of DDR system has improved to the point that it can now be used for estimating canal lengths, even for curved canals, with accuracy comparable to that of conventional radiography

Microbiological analysis of radiographic films and tubes in private and public dental radiographic centres in Yazd [2001]

In dental radiography, there are specific potentials to transmit infection. The goal of this research was to investigate radiographic films and tubes microbiologically in private and pudic dental radiographic centres in the city of Yazd. In this cross-sectional descriptive study [2001], all 13 public and private centres with totally 21 dental radiography machines were investigated. First, sample was collected from different areas of radiography tubes and films' covers by a sterile wetswap. All samples were kept in Tayoglycolate culture media and then put in 37°C incubator in microbiology laboratory. The cloudiness was checked every 24 hours. Data were analyzed using Extended Fisher test. In samples collected from public radiography centres, microbial infections with pseudomonas aeruginosa, Staphylococcus epidermidis, Aspergillus niger and alkagenous were detected probably resulted from hospital infections and healthy carries among hospital personnel. In private centres infections with microbes such as Neisseria sicca, Staphylococcus epidermidis and Bacillus subtilis were detected, a probable consequence of normal flora in the environment. Films' covers in public centres were infected with Staphylococcus aureus, Staphylococcus hemolyticus, Neisseriasicca and Staphylococcus epidermidis probably due to contact with healthy carriers. The methods applied in Yazd radiographic centres, especially the public ones, are completely different from the standards recommended by ADA and CDC. Therefore, our society is definitely exposed to cross-sectional infections along radiographic clinics