@article { author = {Moazzami, Saied Mostafa and Kazemi, Reza and Alami, Maliheh and Attaran, Ebrahim and Mehhary, Michael and Sarmad, Majid and Shahrokh, Heydar}, title = {Light Conduction Capability of Different Light-Transmitting FRC Posts}, journal = {Journal of Dental Materials and Techniques}, volume = {1}, number = {2}, pages = {40-46}, year = {2012}, publisher = {Mashhad University of Medical Sciences}, issn = {2322-4150}, eissn = {2252-0317}, doi = {10.22038/jdmt.2013.92}, abstract = {Introduction: Application of light transmitting posts to restore greatly damaged endodontically treated teeth has been increased. It is suspected that light intensity decreases as it passes throughout different materials. This can reduce the degree of conversion required for adequate bond strength throughout the length of these posts. The objective of this study was to evaluate the amount of light intensity reduction after passing through different depths of FRC posts. Methods: Four groups of five extracted human central incisors were prepared to cement four types of FRC posts with Panavia F 2 resin cement. The apical end of the posts were exposed by sectioning with a diamond disk and then polished. The light intensity measurement was performed using a micro-voltmeter in 8 points or depths with 2mm intervals beginning from the apical depth of 16mm up to a coronal depth of 6mm. Two different output light intensities [HIP (High Intensity Program) and LOP (Low Intensity Program)] were evaluated. Results: Statistical analysis showed significant differences in light intensity at various depths between 6 and 16mm in all groups. These reductions were linear in all specimens; however, the rate of reduction was dissimilar among different FRC posts. HIP and LOP light exposure modes had not the same rate of light reduction. Conclusion: Light intensity decreased dramatically after passing through different depths of FRC posts. None of the posts had sufficient enough light transmission for satisfactory polymerization at the apical and middle levels.}, keywords = {FRC post,light intensity,light transmitting post,thickness}, url = {https://jdmt.mums.ac.ir/article_92.html}, eprint = {https://jdmt.mums.ac.ir/article_92_091205d8e4943796cff48fdb1fc819ab.pdf} } @article { author = {Poosti, Maryam and Basafa, Mohammad and Hosseini, Mohsen and Parvizi, Farnaz}, title = {Changes in the Position of Mandibular Third Molars Following Extraction and Non-Extraction Orthodontic Treatments}, journal = {Journal of Dental Materials and Techniques}, volume = {1}, number = {2}, pages = {47-52}, year = {2012}, publisher = {Mashhad University of Medical Sciences}, issn = {2322-4150}, eissn = {2252-0317}, doi = {10.22038/jdmt.2013.93}, abstract = {Introduction: Impaction of third molars can be associated with a number of sequelae, each requiring a different type of treatment. The purpose of this study was to assess the changes in the position of lower third molars following extraction and non-extraction orthodontic treatments. Methods: Pre- and post-treatment panoramic radiographs of 26 class I malocclusion patients (4 male and 22 female) who were treated on a non-extraction basis were compared with those of 30 class I malocclusion patients (5 male and 25 female) who received orthodontic treatment following the extraction of all first premolars. In each group, the lower third molar angulations and their distance from the lower border of the mandible were assessed. Results: Paired t-tests and independent t-tests detected significant changes in the position of the lower third molars in the extraction group. Both the left and right molars became more upright and their distance from the lower border of the mandible increased. Similar changes were only seen in the position of the right mandibular third molars in the non-extraction group. Conclusion: Tooth extractions can bring about favorable changes in the position of mandibular third molars and possibly reduce their incidence of impaction}, keywords = {extraction,non-extraction,Orthodontics,third molar}, url = {https://jdmt.mums.ac.ir/article_93.html}, eprint = {https://jdmt.mums.ac.ir/article_93_98a8c45c71af7bc4e734d0405e9e318a.pdf} } @article { author = {Madani, Azamsadat and Ghahremanlu, Ahmad and Sabooni, Mohammad Reza and Shahabian, Foad and Harati, Hamzeh}, title = {The Effect of Bridge Orientation in Casting Machine on the Castability and Quality of Base Metal Castings}, journal = {Journal of Dental Materials and Techniques}, volume = {1}, number = {2}, pages = {53-57}, year = {2012}, publisher = {Mashhad University of Medical Sciences}, issn = {2322-4150}, eissn = {2252-0317}, doi = {10.22038/jdmt.2013.94}, abstract = {Introduction: The aim of this study was to evaluate the effect of bridge orientation in casting machine on castability and quality of base metal castings. Methods: Three groups of patterns with different direction and lengths in casting machine were casted and then studied qualitatively and quantitatively using mean and standard deviation in table of frequency. Results: Larger nodules and porosities were on the joints of sprue in horizontal specimens (P=0.01 and 0.048, respectively). There was no significant difference in castability between 3-, 5- and 6-unit bridges in relation to their direction in casting machine (P=0.5). An increase in bridge length led to more variation in length and width. The position of bridges also played an important role in the length variation in bridges. Conclusion: The direction of bridges had no effect on base metal castability but a vertical position resulted in a better casting quality and an increase in length of the bridges caused more defects in castings.}, keywords = {Base metal,casting machine,dental casting technique}, url = {https://jdmt.mums.ac.ir/article_94.html}, eprint = {https://jdmt.mums.ac.ir/article_94_d8f1dbf77a1de3c69ed73060b593287f.pdf} } @article { author = {Farzanegan, Fahimeh and Goya, Ali}, title = {Evaluation of Mandibular Third Molar Positions in Various Vertical Skeletal Malocclusions}, journal = {Journal of Dental Materials and Techniques}, volume = {1}, number = {2}, pages = {58-62}, year = {2012}, publisher = {Mashhad University of Medical Sciences}, issn = {2322-4150}, eissn = {2252-0317}, doi = {10.22038/jdmt.2013.95}, abstract = {Introduction: The purpose of this study was to evaluate the relationship between the position of mandibular third molar (M3) and vertical skeletal malocclusions. Methods: Materials for the study consisted of panoramic radiographs and lateral cephalograms of 73 fifteen to nineteen-year-old class I patients (girls=66%, boys= 34%). Patients were classified into three groups based on four vertical cephalometric indices: FMA, PFH/AFH, LAFH/TAFH, and Y-axis. Analysis of the position of mandibular M3 and its relation to the bone and other teeth were determined by three variables on panoramic view: evaluation of the space for mandibular M3, vertical position of the mandibular M3 in relation to occlusal plane, and spatial relationship between the mandibular second molar (M2) and M3. Results: In girls, there was a significant relationship between the retromolar space in both sides of the jaw and different vertical skeletal malocclusions (P<0.001 and P=0.001, respectively). In boys, significant relationship existed between the retromolar space in both sides of the jaw, spatial relationship between the mandibular M2 and mandibular M3 in the left side of the jaw and various vertical skeletal malocclusions (P=0.021, P=0.026, and P=0.017, respectively). Conclusion: The present study showed significant correlation between the retromolar space and various vertical skeletal malocclusions in boys and girls.}, keywords = {mandibular third molar,retromolar space,vertical skeletal malocclusion}, url = {https://jdmt.mums.ac.ir/article_95.html}, eprint = {https://jdmt.mums.ac.ir/article_95_d07b18b5add46fbad9433384d206947d.pdf} } @article { author = {Heravi, Farzin and Shojaeian, Shiva and Sadafi, Mehdi}, title = {A Comparative Study of Dentoskeletal Changes Following Orthodontic Treatment with First Premolar Extraction in Long Face and Normal Patients}, journal = {Journal of Dental Materials and Techniques}, volume = {1}, number = {2}, pages = {63-69}, year = {2012}, publisher = {Mashhad University of Medical Sciences}, issn = {2322-4150}, eissn = {2252-0317}, doi = {10.22038/jdmt.2013.96}, abstract = {Introduction: The purpose of this study was to evaluate vertical facial and dental changes after orthodontic treatment with extraction of first four premolars, and to find whether long facial height could influence the treatment result. Methods: Fifty-six orthodontic patients with the minimum age of 15, whose treatment plan involved extracting four first premolars, participated in the study. The patients included 30 females and 27 males. Cephalometric measurements before and after treatment were compared using a paired T-test. Independent T-test was employed to compare post treatment changes for each parameter between normal and long face groups. The same analysis performed between male and female subjects. Results: Treatment changes revealed a significant increase in the vertical distance from the upper molar to palatal plane, the lower molar to mandibular plane and Menton to palatal plane in all groups. There was significantly more increase in most post-treatment linear measurements in males than in females, with the same direction in both genders. There were no significant differences between normal and long face in any measurement. Conclusion: All patients showed some extrusion of the molar teeth after extraction of the premolars. The difference between normal and long face groups was not significant.}, keywords = {extraction,facial height,orthodontic treatment}, url = {https://jdmt.mums.ac.ir/article_96.html}, eprint = {https://jdmt.mums.ac.ir/article_96_e7b1ac05d0f275c9b79cc8105bbaff54.pdf} } @article { author = {Khajeh Ahmadi, Saeedeh and Rahpeyma, Amin}, title = {Central Odontogenic Fibroma of the Mandible}, journal = {Journal of Dental Materials and Techniques}, volume = {1}, number = {2}, pages = {70-73}, year = {2012}, publisher = {Mashhad University of Medical Sciences}, issn = {2322-4150}, eissn = {2252-0317}, doi = {10.22038/jdmt.2013.97}, abstract = {A 16-years-old female patient with painless swelling of the right side of mandible is described. She noticed the swelling from two years ago, without painful symptoms. Axial CT imaging showed buccal expansion with intact buccal and lingual cortical bone. The report of incisional biopsy was central odontogenic fibroma. Under general anesthesia the lesion was removed after ostectomy of buccal cortical plate and inferior alveolar nerve preserved. Three-year follow-up after tumor excision relieved no recurrence.}, keywords = {odontogenic tumor,Central odontogenic fibroma,Mandible}, url = {https://jdmt.mums.ac.ir/article_97.html}, eprint = {https://jdmt.mums.ac.ir/article_97_a52c5134c9fcf4c4c5fab5b62c4bdcfe.pdf} }