فهرست مطالب

Dental Materials and Techniques - Volume:7 Issue: 2, 2018
  • Volume:7 Issue: 2, 2018
  • تاریخ انتشار: 1397/01/09
  • تعداد عناوین: 8
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  • Ahmad Ghahremanloo, Mohsen Movahedzadeh *, Abdollah Javan Rashid Pages 53-62
    Introduction
    Marginal fit is a key factor for long term clinical success through any dental restorations. Poor marginal adaptation causes cement dissolution. This can lead to dental caries, gingival irritation, periodontal diseases, and finally treatment failure. The aim of this study was measurement and comparison of marginal gap quantities in metal ceramic and all ceramic dental restorations fabricated by various methods.
    Methods & Materials: A total of 60 complete crowns in 6 groups (n=10) were fabricated as. Follows: Group A: Conventional metal-ceramic collarless restorations. Group B: Metal-ceramic collarless restorations with CAD/CAM wax copings and porcelain layering. Group C: Metal-ceramic collarless restorations with Ceramill Sintron metal copings and porcelain layering. Group D: All ceramic e-max. Press (lithium disilicate) restorations. Group E: All ceramic restorations with CAD/CAM zirconia copings and porcelain layering. Group F: All ceramic CAD/CAM translucent zirconia (Zolid). Replica technique and optical microscope (60 x magnifications) used to gap measurement. Mann whitney and kruskal-wallis tests used to analyze the data.
    Results
    The lowest mean marginal gap seen in group C (29.12) and the highest mean marginal gap seen in group E(78.19)The mean marginal adaptation was better in metal ceramic restorations than all ceramic restorations and the difference was significant (P˂0.001).
    Conclusion
    According to our study, marginal gap of metal ceramic and all ceramic restorations was clinically acceptable (less than 120 microns).
    Keywords: Marginal gap, marginal adaptation, metal ceramic, all ceramic
  • Poonam Kulkarni *, Rahul S. Kulkarni, Rupal J. Shah, Bharti Tomar Pages 63-68
    Introduction
    Flabby or fibrous ridge is one of the consequences of long term wearing of complete dentures. It can develop where hyperplasic soft tissue replaces the alveolar bone and is a common finding, particularly in the upper anterior region of long term denture wearers. Forces exerted during impression making can result in distortion of the mobile tissue unless managed appropriately; such flabby ridges adversely affect support, retention and stability of complete dentures. Many impression techniques have been developed to help overcome this problem. While these vary in the method applied, they are similar in their complexity, are often quite time-consuming to perform and rely on materials not commonly used in contemporary general dental practice. The purpose of this article is to describe an impression technique for flabby ridges usingrubber base impression materials, routinely available in general dental practice.
    Keywords: Flabby ridge, Special tray, Mishmash impression technique, Rim handle
  • Neda Naghavi, Mina Zarei, Maryam Gharechahi *, Ali Bagherpour, Zahra Owsati Pages 69-74
    Introduction
    Statement of the Problem: Cleaning and shaping are regarded as the most important aspects of root canal therapy and prerequisite for the success of endodontic treatment. Apical transportations can jeopardize the outcome of treatment due to the significant decrease in the sealing ability of root filling material. The purpose of this study was to evaluate transportation in type II canals with two preparation techniques.
    Materials And Method
    Twenty lower first molars were selected and divided into 2 groups of 10. In the first group, the lingual canal of the mesial root was selected as the main canal and prepared up to the WL. The other canal (buccal) was prepared up to the juncture point. In the second group, both canals in the mesial root were prepared up to the working length. The amount and direction of canal transportation in each group were determined in five sections from 2 mm above the juncture point of the canals to 2 mm below the juncture point in 1-mm increments.
    Results
    There were no significant differences between the two techniques in causing transportation in both buccolingual and mesiodistal directions in each increments (P>0.05).
    Conclusion
    Both preparation techniques caused transportation in both mesiodistal and buccolingual directions.
    Keywords: Cone-beam computed tomography, Root canal therapy, Root canal transportation, Type II configuration
  • Taraneh Movahhed, Mahboobe Dehghani *, Tayyebeh Ghoddusi Pages 78-82
    Introduction
    Mobile phones and computers are a reservoir of growth and transmission of microorganisms. This study aimed to evaluate the microbial contamination of computers and mobile phones used by students of an academic dental school, compared to the students of a non-medical school.
    Methods
    Sampling was performed on 44 computers and 45 mobile phones in a dental school (test) and a non-medical school (control). Samples were obtained from the Enter and Backspace keys of keyboards, the left-click button of computer mice and touch-screen of mobile phones. Afterwards, the samples were cultured, followed by colony count.
    Results
    The most frequently detected microbes were coagulase-negative Staphylococci, Bacillus and Micrococcus. In computer samples, pathogenic bacteria including Staphylococcus aureus and Klebsiella, were found only in the samples of the dental school. Staphylococcus aureus and Micrococcus were significantly more prevalent in the test group. Microorganisms belonging to human normal flora (e.g., Bacillus, Entrococcus, Corynebacterium, and Tetragenococcus) were significantly more prevalent in computers of the control group. In terms of the frequency of pathogenic bacteria found on mobile phones, no significant difference was observed between the study groups.
    Conclusion
    The prevalence of normal human flora was higher in the control group (non-medical) relative to the test group (dental). Meanwhile, pathogenic bacteria were more prevalent in the samples of the dental school. Also, computers were more contaminated than mobile phones. Hygiene promotion programs should be implemented in both dental and non-medical schools.
    Keywords: Microbial colony count, Equipment Contamination, Cell phone, Computers, Dentistry
  • Mohammad Amin Khajavi, Zahra Meshkat, Alireza Pasdar, Ala Ghazi, Sina Gerayli, Elham Banihashemi, Pegah Mosannen Mozafari * Pages 83-88
    Introduction
    Lichen planus is a chronic inflammatory disease in oral mucosa and skin. Recently, reports have demonstrated a possible relationship between lichen planus and liver diseases. During the past decade, there has been a hypothesis regarding viral etiological agents that have been found to be in association with hepatotrophic viruses known as Hepatitis B and C with LP. This research was studied in Mashhad, northeast of Iran, to find a relationship between OLP and HBV infection.
    Methods
    Age and gender of 134 patients (with OLP) and 134 controls (without OLP) were not matched and their serum samples were respectively screened for HBsAg by ELISA (third generation) and polymerase chain reaction (PCR) for HBV-DNA.
    Results
    Tests were positive (for both HBsAg and HBV-DNA) for 9 patients (6.71%) with OLP and 2 healthy individuals (1.49%) infected with HBV (P=0.03).
    Conclusion
    There was a relationship between HBV and OLP in our population. Based on our findings, it is recommended that viral serology for Hepatitis B and OLP patients be conducted as a routine screening process.
    Keywords: Hepatitis B, Viral Infections, Lichen Planus, Oral, Epidemiology, Iran
  • Ali Bagherpour, Iman Moshtagh-Khorasani, Atie Safaee * Pages 89-96
    Introduction
    The present study was aimed at evaluating common positioning errors on panoramic radiographs taken in the Radiology Department of Mashhad Dental School.
    Materials And Methods
    The study sample included 1,990 digital panoramic radiographs taken in the Radiology Department of Mashhad Dental School by a Planmeca Promax (Planmeca Oy, Helsinki, Finland), during a 2-year period (2010–2012). All radiographs, according to dentition and sex, were evaluated for positioning errors.
    Results
    There were 1,927 (96.8%) panoramic radiographs with one or more errors. While the number of errors in each image varied between one and five, most images had one error (48.4%). The most common error was that the tongue was not in contact with the hard palate (94.8%). "Open lips" was an error not seen in any patients.
    Conclusions
    positioning errors are common in panoramic radiographies. The most common error observed in this study was a failure to place the tongue on the palate. This error and the other errors reported in this study can be reduced by training the technicians and spending little more time for patient positioning and more effective communication with the patients.
    Keywords: panoramic radiography, diagnostic imaging, patient positioning, quality improvement
  • Soudabeh Sargolzaei, Saede Atarbashi-Moghadam *, Fatemeh Latifi Pages 97-100
    Osteoblastoma is a rare solitary osteoblastic bone neoplasm. It is characterized by proliferation of osteoblasts forming trabeculae within a vascular fibrous stroma. There is a variety of jaw bone lesions with very close clinical, radiological and microscopic interrelations, which make diagnosis more challenging. Familiarity with these rare bony lesions is vital for oral pathologists. This report presents a new case of asymptomatic mandibular osteoblastoma occurring in a 43-year-old male.
    Keywords: Osteoblastoma, Bone, Benign, Neoplasm, Mandible
  • Nooshin Mohtasham, Arash Dehghan, Mahdi Gholami, Mehdi Shahabinejad * Pages 101-104
    Introduction
    This is to report a rare case of sebaceous carcinoma of inner cantus of the eye in relation with rare skin lesions of epidermodysplasia verruciformis. Epidermodysplasia verruciformis is a rare skin disease which is caused by human papilloma virus.
    Sebaceous carcinoma is a rare entity which is derived from sebaceous glands and to our best knowledge this is for the first time that we observe sebaceous carcinoma arising from lesions of epidermodysplasia verruciformis at the inner canthus of the eye.
    We report a 50 years old male patient who admitted to our hospital 3 years ago.
    Keywords: Sebaceous carcinoma-Epidermodysplasia verruciformis – Inner cantus