Showing 8 results for Fallah
F. Fallahian ,
Volume 16, Issue 2 (8 2003)
Abstract
The health of habitants, living in un-fluoridated drinking water areas, can be endangered through fluoride intake from food, beverages, tooth paste and dentistry products. Fluoride is used in mouthwash, toothpaste, juice fruits, conserved foods and Teflon dishes. Water exposure to fluoride occurs through fertilizers, aluminum industries, insecticides, pesticides, herbicides and fungicides used for fruits and vegetables which ultimately lead to environmental fluoride pollution. Some side effects.caused by chronic fluoride intake are as follows: decrease of hemoglobin concentration, gastrointestinal disorders, and tooth loss at young age, osteofluorosis, hip fracture among aged people, osteosclerosis,osteoporosis, special forms of arthritis and joint ankylosis, metaphysial osteomalacia, mottling and weak structure of tooth, insulin secretion and glucose tolerance test disorders, decrease of urine concentration,immune system disorders, genetic defects and cancer, learning disabilities and IQ(intelligence quotient)deficits and thyroid dysfunction The present article was to investigate the side effect of excessivefluoride intake and to discuss different preventive and diagnostic ways.
Sh. Shahrabi , B. Abdolahi , H. Ahadian , H. Fallahzadeh,
Volume 18, Issue 3 (11 2005)
Abstract
Background and Aim: A strong causal relationship exists between cigarette smoking and development of oral squamous cell carcinoma, so oral screening using exfoliative cytology has been recommended to facilitate the early diagnosis of cellular alterations in oral mucosa and silver staining (AgNOR technique) has been proven to be of value in the detection of incipient cellular alterations. The purpose of this study was to compare the argyrophilic nucleolar regions (AgNORs) count of cells collected from normal mucosa of cigarette smokers with that obtained from non- smokers.
Materials and Methods: In this cross-sectional study, cytologic smears of normal tongue, buccal mucosa and floor of the mouth from 19 smokers and 19 non- smokers were stained for AgNORs. The AgNORs count was established on 100 cells. The count value of groups were compared and analyzed using the Levens, Paired T, Student and Factorial tests. Using P<0.05 as the limit of significance.
Results: The AgNORs were round and had a clustered distribution in both groups. The mean AgNORs count was statistically higher in cells of smokers than non- smokers (P<0.05). There was a significant difference between smears from the floor of the mouth and other anatomical sites in both groups. In this study, no correlation was found between AgNORs count and gender.
Conclusion: Analysis of AgNORs suggests that there might be a correlation between the smoking habit and an increased rate of cellular proliferation in the oral mucosal cells.
M. Ghavam , M. Ataee , F. Fallahzade ,
Volume 19, Issue 1 (3 2006)
Abstract
Background and Aim: With recent introduction of packable composites, it is claimed that they apply less stress on tooth structure because of reduced polymerization shrinkage, and similarity of coefficient of thermal expansion to tooth structure. However, the high viscosity may in turn cause less adaptation, so it is not clearly known whether these materials strengthen tooth structure or not. The aim of this study was to evaluate fracture resistance of maxillary premolars, receiving hybrid or packable composite restorations with different methods of application and curing.
Materials and Methods: In this experimental study, seventy five intact premolars were randomly assigned to five groups of 15 teeth each. One group was maintained intact as the control group. Similar MOD cavities were prepared in the other teeth. The teeth in group two were restored with Spectrum in incremental layers and light cured with 500 mw/cm2 intensity. The third group were filled with Surefil and cured with light intensity of 500 mw/cm2. The groups four and five were restored with Surefil in bulk technique with two different modes: 500 mw/cm2 intensity and a ramp mode (100-900 mw/cm2) respectively. After thermocycling, force to fracture was assessed and degree of conversion (DC) at the bottom of cavities was evaluated for different modes and methods. The curing and placement methods in groups tested for DC (A to D) were the same as fracture resistance groups (2 to 5). Data were analyzed using one way ANOVA and Tukey HSD tests with p<0.05 as the limit of significance.
Results: All the restored groups showed significantly less fracture resistance than the control group, but had no significant difference among themselves. DC of Spectrum was higher than Surefil. Bulk method with 500 mw/cm2 light intensity, significantly decreased DC. DC in bulk method with high light intensity was not significantly different from incremental method with 500 mw/cm2 light intensity.
Conclusion: Placement techniques, light intensity and type of composite had no influence on the fracture resistance. The use of packable composite with bulk technique and 500 mw/cm2 intensity or less is not recommended in 4 mm depth cavities due to insufficient DC.
M. Fallahinejad Ghajari , S. Nabavi Razavi ,
Volume 20, Issue 1 (4 2007)
Abstract
Background and Aim: Extensive and continuous consumption of acidic drinks is the main cause of enamel erosion in human teeth. The purpose of this study was to compare the erosive potential of two Iranian drinks with those of two imported ones.
Materials and Methods: Two Iranian drinks (Cola Zamzam and Orange Zamzam) and two imported ones (Pepsi and Miranda) were studied in this experimental invitro study. 120 intact premolar teeth, extracted for orthodontic reasons were divided into 3 equal groups (A, B and C). Each group was exposed to one of the drinks for exposure times of: A: 15 minutes, B: 45 minutes and C: 12 hours. Each group was divided into 4 subgroups (each containing 10 teeth), which were exposed to 20 ml of one of the 4 drinks. The exposed surface was the same in all samples (a 5 mm in diameter semi circular window). The amount of Ca++ ion (mg/ml) added to each drink at the end of exposure time was estimated by atomic absorption spectrophotometer.
Results: 2 way ANOVA showed that the drinks were significantly different with regard to released Calcium ion. Time had significant effect on erosive potential. The two mentioned factors had significant interaction (P<0.001). The most erosive effect was seen in 12 hours in all of the drinks. The erosive effect of Orange Zamzam in 15 minutes and Pepsi in 45 minutes and 12 hours was significantly more than other groups (P<0.001).
Conclusions: Pepsi had the most long term erosive effect among the four drinks, and Cola Zamzam had the least erosive potential.
Hosein Fallahzadeh, Ahmad Haerian, Nader Bahrami,
Volume 25, Issue 3 (1 2012)
Abstract
Background and Aims: Increasing demands for health care's services on one hand and limited resources on the other hand brings about pressure over governments to find out a mechanism for fair and appropriate distribution of resources. Economic analysis is one of the appropriate tools for policy making on this priority. The aim of this study was to assess capital and consumption of oral health units of health care centers in Yazd city and comparing it with revenue of these centers and determining of cost effectiveness.
Materials and Methods: In this descriptive cross sectional study, all health care centers of Yazd city with active dentistry department were evaluated. The data has been extracted from current documents in health care center of county based issued receipts and daily information registers.
Results: Expended cost for providing of oral hygiene services in second half of 2008 in 13 medical health centers of Yazd included active dentistry section was 557.887.500 Rials and revenue to cost ratio was about 34%. The most provided service was related to tooth extraction and the average of tooth restoration in each working day was 0.48.
Conclusion: With attention to low tariffs of dentistry services in medical health centers and paying subsidy to target groups, expenses of oral hygiene are always more than its revenue.
Mohammad Hosain Lotfi Kamran, Mahnaz Hatami, Abbas Fallah Tafti, Mohammad Malekzadeh,
Volume 30, Issue 3 (10-2017)
Abstract
Background and Aims: To create a good adhesion between porcelain veneers and zirconia restorations has been important issues is the prosthesis. The aim of this study was to identify an effective way to prepare the zirconia surface infrastructure to increase its shear bond strength to the porcelain veneer.
Materials and Methods: 75 samples of zirconia (Y-TZP) cylinders (diameter of 7 mm and a thickness of 3 mm) were fabricated. Based on the surface treatment, specimens were randomly divided into 3 groups: control, air abrasion and
Er-YAG laser. After surface treatment, the specimen surfaces were examined by SEM. Using a metal mold, the porcelain was veneered on the zirconia surface and then fired. After thermocycling, the shear bond strength of porcelain to zirconia was measured and then the failure mode of each specimen was analyzed using a stereo-microscope. Data were analyzed by one-way ANOVA and Tukey test.
Results: Significant differences were observed between the mean shear bond strength of different groups (P=0.001). The greatest amount of shear bond strength was observed in the group (S) and the lowest bond strength in the control group. Analysis of failure modes showed no statistically significant difference in the type of failure among study groups. The adhesive failure was predominating failure at the intersection of porcelain veneers.
Conclusion: The highest shear bond strength between zirconia and porcelain was achieved by sandblasting the zirconia surfaces compare with that of Er_YAG application.
Abdolrahim Davari, Alireza Danesh Kazemi, Mehrrnaz Fallah Tafti,
Volume 30, Issue 4 (1-2018)
Abstract
Background and Aims: A suitable restorative material must have acceptable mechanical properties. The aim of this study was to evaluate the effect of conventional acidic drinks on the micro-hardness of two dental resins.
Materials and Methods: 48 samples of each of P60 and G-aenial composites were prepared and randomly divided into six groups: Coca-Cola, Fanta, yoghurt drinks, soft beer, Sprites and control groups. The study was in 3 steps: after one day in distilled water and after one day and one week of immersion in beverages per day
(6 hours). The Vickers micro-hardness was then evaluated. Finally, data were analyzed by, t-tests, ANOVA and Tukey tests.
Resultes: Comparing the results between the two groups, a significant difference between the two composite was found. After one day in the water, the average micro-hardness for P60 was of 27.12 (kgf/mm2) and 16.51 (kgf/mm2) for G-aenial amount and these differences were found statistically significant (P=0.0001). For the
6-hour maintenance interval, the average micro-hardness between P60 and G-aenial was statistically significant (P=0.0001). For 42 hours, the average micro-hardness ranged between P60 and G-aenial that were statistically significant (P=0.0004). The stiffness of the P60 composite after 42 hours’ storage in soft beer significantly decreased compared with the control group (P=0.03). G-aenial composite hardness after 42 hours of soaking in the Coca-Cola was reduced significantly compared to yogurt drinks (P=0.02).
Conclusion: As a result, the hardness of P60 composite was higher than that of G-aenial. The hardness of both composites reduced in acidic drinks after one week.
Alireza Daneshkazemi, Abdolrahim Davari, Zahra Usefi, Niloofar Fallah, Solmaz Ghanbarnejad, Pedram Daneshkazemi,
Volume 33, Issue 3 (10-2020)
Abstract
Background and Aims: Adding nanoparticles to dental composite resins, could reduce bacterial adhesion and secondary caries. Thermocycling can resemble in-vitro conditions to the oral environment. The aim of this study was to determine the effect of thermocycling on the microleakage of a mixture of copper oxide nanoparticles and flowable composite.
Materials and Methods: In this in-vitro study, 88 premolar teeth were divided into eight groups based on the application of copper oxide nanoparticles with concentrations of 0.1% and 0.3% w/w and thermocycling by 0, 1000, 5000 and 15,000 cycles. The occlusal grooves of the teeth were sealed with the mixture of flowable composite and copper oxide nanoparticles, and the teeth were thermocycled. Next, the teeth were immersed in methylene blue 2% solution for 24 hrs and were cut and the microleakage was evaluated by a stereomicroscope (hp/USA). Data were analyzed using Kruskal-Wallis and Mann-Whitney tests at the significance level of 0.05.
Results: In the groups with 0.1 % copper oxide nanoparticles, the mean microleakage increased significantly with increasing the number of thermocycling rounds (P=0.032). The difference in the microleakage between the groups exposed to 0 and 15,000 termocycling was significant (P=0.019). However, thermocycling had no significant effect on the microleakage of groups with concentration of 0.3% (P=0.780). The specimens subjected to the 0, 1000, 5000 and 15000 thermocycling in two concentrations of copper oxide nanoparticles showed no significant difference in the microleakage.
Conclusion: In groups containing copper oxide nanoparticles with a concentration of 0.1%, the microleakage increased by increasing the number of thermocycling up to 15,000 cycles compared to the control group. However, this did not have significant effect for the concentration of 0.3% copper oxide nanoparticles.
