Showing 7 results for Nejati
F Nejatidanesh , A. Tavakoli , A . Haratian ,
Volume 16, Issue 3 (10 2003)
Abstract
Statement of Problem: Rotary dental instruments (i-e. iow speed and high speed handpieces), due to infection spread high potentiality, should be sterilized between dental visits for each patient. When a high speed rotary instrument pauses at a high velocity, contaminated fluids like blood and saliva will be sucked into its tubes.
Purpose: The aim of this study was to compare the bactericidal effects ofDeconex 53 plus solution and the solarsept spray on dental high- speed instruments.
Materials and Methods: In this experimental study, one hundred and twenty (120) dental high- speed turbines, sterilized by autoclave, were divided into 6 groups. The turbines were contaminated with bacterial suspension. Streptococcus mutans, Staphilococcus aureus and Neisseria SP were the first microbial groups. Pseudomonas aruginosa was the second microbial group and Bacillus subtilis spore
was the third microbial group. After 5 minutes, three contaminated groups were placed in Deconex53 plus 2% solution for 15 minutes. Three other groups after contamination were sprayed with Deconex soiar sept spray for 2 minutes. Then the samples were placed in TSB culture and after 24 hours incubation at 37°, the samples were transmitted on blood agar solid culture for bacterial viability observation. The results were observed after 24 hours incubation. Proportional test with normal distribution was used for data analysis.
Results: The Deconex 53 plus had 85% disinfectant activity on the first microbial group, 10% on the second microbial group and 100% on the third microbial group. Also the solarsept spray had 30% disinfectant activity on the first microbial group and 15% on the third micribial group . The solarsept spray had no bactericidal effect on turbines contaminated by the second microbial group. The results proved that the disinfectant effects of Deconex 53 plus solution for 15 minutes were significantly better than the solarsept spray for 10 minutes. The Deconex solution and the solarsept spray showed 65% and 15% negative growth, respectively. Based on the elimination of all spores, Deconex 53 plus has great sporcidal activity.
Conclusion: These disinfectants should not be considered as suitable substitutes for sterilization with
autoclave.
O. Savabi , R. Mazaheri , S. Shadzi , F. Nejatidanesh ,
Volume 16, Issue 4 (9 2004)
Abstract
Statement of Problem:The surface topography of denture base material is an important factor for the adhesion of Candida albicans and other microorganisms.
Purpose: The aim of this study was to evaluate the adherence of Candida albicans to four types of denture base materials (Acropars acrylic resin, Meliodent acrylic resin, rough and smooth surfaces of Molloplast B).
Materials and Methods: Seven blocks of two types of acrylic resins and ten blocks of silicone with one rough and one smooth surface were made and incubated in a suspension of Candida albicans. After washing,the blocks were stained with acridine orange and examined under fluorescent microscope. For statistical analysis ANOVA and Duncan tests were used.
Results: It was observed that Candida adhesion to rough surfaces of acrylic resins and silicone was significantly more than polished surfaces of acrylic resins and smooth silicone (PO.0001). However, no
statistical significant difference was found between polished acrylic resins surfaces and smooth silicone.
Conclusion: Significant differences in the adherence of Candida to the surfaces of different denture base
materials are due to differences in surface topography, chemical, physical and hydrophobic properties so it is
recommended to minimize the roughness and irregularities of denture base.
F. Nejatidanesh , O. Savabi , Mr. Azad ,
Volume 18, Issue 2 (4 2005)
Abstract
Statement of Problem: One of the greatest problems in metal –ceramic restorations is debonding of porcelain from dental alloys. Production of dental alloys by Iranian companies necessitates the evaluation of physical and handling properties of these products.
Purpose: In this study the bond strength between porcelain and two types of base metal alloys, Supercast (with beryllium) and Minalux (without beryllium) was investigated.
Materials and Methods: In this experimental study 10 cylindric bars from each base metal alloy were prepared. The bars were degassed and porcelain was applied around them in a disc form (8 mm diameter and 2 mm thickness). The bond strength of porcelain to metal bars was tested with the shear strength test by Instron. Data were analyzed with student t-test and P<0.05 was considered as the limit of significance.
Results: The mean failure load was 71.58±6.4 KgF for Supercast and 67.34±5.48 for Minalux alloy. The bond strength of Supercast and Minalux were 55.85±4.99 MPa and 52.54±4.27 MPa respectively. The difference was statistically significant (P0.001).
Conclusions: This study showed that nickel-chromium-beryllium alloy (Supercast) produced significantly better ceramometal bonding than nickel chromium alloy without beryllium (Minalux).
F. Nejatidanesh , O. Savabi , B. Sarrafpour , D. Mirabi ,
Volume 20, Issue 1 (4 2007)
Abstract
Background and Aim: Proper designing of partial denture frameworks is the duty of dentists, but this task is often abdicated to technicians because of lack of time and experience. Computer assisted learning and designing can be used for both training dental students and helping dentists design proper frameworks. As the first step to prepare software for framework designing, this study evaluated the agreement on different framework designing principles, among prosthodontists of dental schools in Iran.
Materials and Methods: A questionnaire consisting of 121 design rules was sent to 41 prosthodontists at seven dental schools in Iran .The percentage rate of agreement on results was used for data analysis.
Results: The percentage of rules accepted by more than 60% of the prosthodontists was 76.2%. It consisted 80% saddle rules, 76.2% rest rules, 78.4% clasp rules, 63.6% maxillary major connector's rules and 80.9% mandibular major connector rules.
Conclusion: The percentage of accepted rules by Iranian prosthodontists was 76.2%. Maxillary major connectors had the least acceptance.
F. Nejatidanesh , O. Savabi , B. Sarrafpour , D. Mirabi ,
Volume 20, Issue 2 (9 2007)
Abstract
Background and Aim: Designing removable partial dentures is one of the most important phases of prosthetic treatments. Computer can be used to facilitate and increase accuracy of removable partial denture design. The aim of this study was to develop a software for removable partial denture design.
Materials and Methods: A questionnaire (discussed in part I) and major textbooks, were used to determine the design rules. The software (RPD Graph) was developed using Visual C++ and Maryam program. The RPD Graph can determine the classification of partial edentulous arch. With defining the missing teeth and providing data about prognosis and conditions of abutment teeth, the removable partial design will be developed by RPD Graph. This software is a knowledge-based system which has specific characteristics. It can be used as an educational tool for teaching RPD design and as a clinical tool for supporting clinician's decision. In addition it can be developed to more complete softwares.
D. Goodarzi Pour, S. Nejati, A. Fotouhi,
Volume 24, Issue 1 (23 2011)
Abstract
Background and Aims: Conventional radiological equipments in our country are going to be converted to digital system using computed radiology (CR) technology. If we know the accuracy of digital panoramic radiography for detection of small defects in tooth, it will be useful in cases with difficulty for taking the intraoral radiographs. The aim of this study was to evaluate sensitivity and specificity of digital panoramic radiography for detection of proximal caries compared with the bitewing radiography.
Materials and Methods: One-hundred patients who had been ordered for taking both bitewing and panoramic radiography were included in this study. Panoramic and then bitewing radiographs were observed by a maxillofacial radiologist and interproximal caries were recorded. Sensitivity and specificity of digital panoramic radiography (CI=95%) was calculated compared with the bitewing radiography as a gold standard.
Results: This study showed that the values for sensitivity and specificity were 62.7% (CI 95%=57.7%-67.5%) and 91.0% (CI 95%=89.2%-92.5%), respectively.
Conclusion: Sensitivity of digital panoramic is less than bitewing radiography even with processing before printing. Therefore, bitewing radiography is superior for detection of inter proximal caries.
Marzieh Alikhasi, Narges Ameri, Hakimeh Siadat, Ahmad Reza Shamshiri, Mohammadreza Nejati,
Volume 32, Issue 1 (7-2019)
Abstract
Background and Aims: Passive fitness of implant frameworks are important factors for long-term success of dental implant restorations. The aim of this in vitro study was to evaluate the dimensional changes of implant supported zirconia frameworks fabricated by Zirkonzahn CAD/CAM system during fabrication stages.
Materials and Methods: The master model of 3-unit FDP was made of two implant abutments. The master model was scanned 12 times and data were saved as STL files (scanning groups). Using semi-sintered zirconia,
12 real-size frameworks (milling groups) and 12 enlarged frameworks which were then sintered (sintering group) were made in this system. Dimensions of master model and specimens of each stage were measured. The dimensional changes in respect to master model were calculated. Data were analyzed using Repeated measures ANOVA, independent t-test, and paired sample t-test at α=0.05 of significance.
Results: The milling stage showed greater dimensional changes comparing to the other stages (P<0.05). At all stages, the dimensional changes of premolar abutment height were greater than canine (P<0.001).
Conclusion: Within the limitations of this study, the results suggested that the fabrication stages and size of abutments had significant effects on the dimensional changes of zirconia frameworks.
