Journal of Dental Materials and Techniques
Volume:2 Issue: 2, Spring 2013

The purpose of this study was to compare the accuracy of the torque wrenches used in different dental implant systems. We evaluated 42 torque wrenches used in different dental clinics in Mashhad, Iran, using a digital torque meter (Mark 10). High (25, 30 and 35 N·cm) and low (15 N·cm) levels of torque were examined. Ten tests were performed on each wrench, and the mean value was considered as the real torque of the instrument. Different characteristics (Model (spring or friction), System, Duration of use, Sterilization, Calibration) of each wrench were also recorded. The difference between the torque applied by the instrument and the target torque required was calculated numerically and as a percentage. A one-way ANOVA and Student’s t-test were used for statistical analysis. There was a significant difference between the error at higher torques in the spring wrenches compared with the friction wrenches (P<0.05). At higher torques, an error greater than 10% was more common in the friction wrenches (29.4%) than in the spring wrenches (4.3%). No significant differences were observed regarding the duration instruments usage and the mean numerical error at high and low torque. In the wrenches that had been used for more than three years, 21.1% of samples showed an error of more than 10%, compared with 9.5% in wrenches that had been used for less than three years (P=0.39). At higher torques the Straumann system produced the least error and the Biohorizon system produced the greatest error which was significantly greater than the other systems (P<0.05). Our results indicate that spring wrenches produce more accurate results than friction wrenches; however, friction wrenches are more reliable at lower torques than higher torques. The length of time in use and sterilization of torque wrenches does not affect the function of the instruments significantly. The precision of the instrument system used is also important.

gender specification among the forensic dentistry and human anthropology, is mainly based on anatomic variations. Due to racial differences and environmental factors such as time of tooth extraction, osteoporosis, dietary habits, usage of dental prosthetics and periodontal diseases, there will be different results achieved. The purpose of this study is to classify the gender specification in edentulous patient by using anatomical variations in panoramic radiography. Panoramic radiographs of a population including 45 men and 45 women which were aged between 51 to 79 years were assessed and statistically analyzed. Analysis of data demonstrated that the average of measured distances in male were significantly higher than female except for the distance between the two mental foramina. It should be signified that the accuracy of gender specification with this method was ranged between 78 to 84.5 percent in female and between 80 to 89 percent in male. The Method of this study can be used as a quantitative technique along with other methods of gender specification. Furthermore, this study has been illustrated as one of the most significant approvals for the existence of sexual dimorphism in Iranian population

Post and core has been considered for endodontically treated tooth, especially in cases with severe damage crowns. Recently fiber reinforced composite posts (FRC post) have been used in the treatment of endodontically treated teeth. Because the length and diameter of posts are effective in stress distribution, the purpose of this study is to evaluate the effect of length and diameter of FRC post on fracture resistance. In this experimental study, 36 glass fiber posts with combination of 7mm, 9mm, and 12mm length and 1.1mm, 1.3mm and 1.5mm diameter were divided into 9 groups of 4. These posts were cemented in root canals by Panavia. Samples were tested with 45° compressive forces for the evaluation of fracture resistance. Datas were analyzed using SPSS soft ware and One- way and Two-way ANOVA analyses. Fracture resistance did not increase significantly with the effect of length and diameter simultaneously (P=0.85). Samples with 12mm length and 1.5mm diameter had the greatest fracture resistance (1023/33N±239/22). The minimum fracture resistance had occurred in post with 7mm length and 1.5mm diameter (503/13N ±69/18). Fracture resistance increased significantly by increasing the length and the same diameter. It can be concluded that fracture resistance is affected by the length and not the diameter of FRC post.

Although proximal dental caries are very common, clinical examinations cannot detect them all. Panoramic radiography has been widely used in dentistry for both diagnosis and screening. This study aimed to investigate and compare the efficacy of two digital panoramic radiography techniques in the diagnosis of proximal caries. A total number of 60 patients referred to a dental radiology center, all had complete dental system and bitewing radiographies, were included. The patients were randomly divided into two groups of 30 patients. For the first and second groups, CR and DR images were obtained respectively. Images were obtained from the distal of the third tooth to the distal of the eighth. Bitewing images were compared with CR and DR images regarding the detection of caries. Kappa index and chi-squared statistics were employed to analyze the results. There was a high agreement rate between bitewing images and CR (Kappa=0.775) and DR (Kappa=o.762) images in detecting caries. Also no significant difference was shown between CR and DR techniques in the detection of caries (0.543). However, DR and CR images are not efficient enough to be prescribed as the sole imaging technique to detect proximal caries. DR and CR techniques could be good imaging techniques for the detection of dental caries as a companion to clinical examinations

There are conflicting reports on the effects of surgical removal of impacted mandibular third molars on the periodontium of the adjacent teeth. The aim of this study was to compare the condition of the periodontium six months after extraction of impacted mandibular third molars with baseline values. Fifty patients with mesioangular impacted mandibular third molarsparticipated in this study. Probing depth (PD), Leo and Sillnes's gingival index (GI), and clinical attachment level (CAL) in distobuccal, mid-distal, and distolingual surfaces of second molar teeth were assessed before surgical extraction of the third molars and 6 months later. To evaluate the changes in alveolar bone height (BH), two parallel PA radiographs obtained at the baseline and follow-up session. Data was analyzed with SPSS 11.0 software atthe confidence interval of 95%. Thirty-eight females and 12 males participated in this study. Twenty-eight(56%) of impacted molar teeth were in the right side and 22 (44%) were in the left side. Baseline values of PD, CAL, and GI at three points of the distal surface of the mandibular second molar tooth had no significant differences with follow-up values (P-value> 0.05). According to the radiographs, baseline BH also had insignificant difference with follow-up height (P-value>0.05). Surgical removal of impacted mandibular third molar does not affect periodontium after 6 months.

Cone beam computed tomography is a useful technique for imaging the craniofacial lesions. It produces more realistic images that facilitate interpretation. Juvenile ossifying fibroma (JOF) is a rare and benign fibro-osseous neoplasm that arises within the craniofacial bones, especially in the maxilla. Mandibular lesions can be seen in 10% of the cases.In both jaws, it has a predilection for the premolar and molar regions (it is mostly seen in premolar and molar regions). Radiographically, it can be present as a radiolucent, mixed or radiopaque lesion. Radiodensity varies from purely radiolucent masses to mixed densities with prominent radiopacity as the lesion matures. This case report highlights a JOF with large foci of odontome-like radiopacities in a 6-year-old boy's mandibular anterior region. The location of the lesion in the anterior mandible and comparatively rapid formation of large odontome-like radiopaque foci at this early agehas made it a rare entity.

Intraosseous movement of an unerupted tooth across the midline of the jaw is known as dental transmigration. This infrequent event is mostly found in the mandibular canines. There are four new cases of mandibular canine transmigration presented here. The literature on this anomalous phenomenon is also reviewed.