Showing 14 results for arian
F. Geramipanah , M. Meemarian ,
Volume 11, Issue 2 (8 1998)
Abstract
In Present study a digital model of hemimaxillectomy was reconstructed by computer and stress distribution of removable partial dentures in tissues, periodontal ligament and bone were thoroughly evaluated. The maximum stress of two different removable partial denture designs which contained buccal and lingual c-shaped clasps respectively were analyzed and compared. It was assumed that a 90 gram force which is equal to an average obturator’s weight is applied outwardly. The results showed that the maximum stress distribution in these two designs is not significantly different.
M. Ghavam Nasiri , R. Goharian , A. Madani , T. Salari,
Volume 17, Issue 2 (7 2004)
Abstract
Statement of Problem: Parafunctional habits are the most important factor in the creation of non-carious cervical lesions and correcting of these habits may affect cervical lesions.
Purpose: The goal of this study was to survey the effects of one-year occlusal adjustment on clinical success of non- carious cervical restorations.
Materials and Methods: In this clinical study, sixty tooth-colored cervical restorations on canines and premolars in patients with parafunctional habits (bruxism and clenching) were studied. The teeth, according to the type of restorative material, were randomly divided into two groups: One group with a composite resin (Tetric Flow Group A: n=30) and the other group with a compomer (Compoglass Flow Group B: n=30). After restoration, each group was divided into two subgroups: (A1, B1) with occlusal adjustment (case group), (A2, B2) without occlusal adjustment (control group). The evaluation was perfumed single blind at 6 and 12 months after restorative operations according to Us Public Health Service (USPHS) classification. Assessment criteria included: marginal integrity, marginal discoloration, recurrent caries, postoperative sensitivity and loss of filling. Statistical analysis was completed using Fisher’s exact test.
Results: In 12 month period between two groups of compoglass Flow restorations, group B1 showed superior results than group B2, however, no significant difference was found between both groups of tetric flow restorations (A1 and A2). There was also no difference in clinical conditions between A2 and B2 groups.
Conclusion: Considering the results of this study, it can be concluded that occlusal adjustment puts a considerable effect on clinical success of compoglass non- carious cervical restorations. However, it should be mentioned that such and effect was not found among Tetric flow restoration.
M. Memarian , R. Masoomi ,
Volume 17, Issue 4 (7 2005)
Abstract
Statement of Problem: Choosing an appropriate tooth for edentulous patients is a very important step in dentistry.
Purpose: This research has been done for determination of proper procedure for tooth selection in edentulous patients.
Methods and Materials: In this cross- sectional study 100 student and people who have come to a medical
center (range 20-30 years old) were collected randomly and the size of their anterior teeth were determined. A gauge with 0.01 mm accuracy and flexible plastic millimeter was used in order for measurement of anatomic landmark. For achieving the relation between the sizes of teeth statistical analysis was done.
Results: 50% of patients were female and the other 50% were male. We found a relationship between mesiodistal width of six maxillary anterior teeth and mesiodistal width of six mandibuMary teeth that can be shown as follow In men: six mandibular anterior teeth width= 0.S3 * width of six maxillary anterior teeth -2.008 In women: six mandibular anterior teeth width- 0.56 * width of six maxillary anterior teeth + 9.53 Also strong meaningful relationships between width of six anterior maxillary teeth and the width between corners of the lip in curve position have been noticed only in men which can be show' as follow:width of Six mandibular anterior tceth= 39.63 + 0.21+ the width between corners of lip in curve position for men
Conclusion: Although there are different ways for prediction of teeth size, it seems these findings can be
helpful in determining and prediction of it.
H. Safarcherati , H. Alaghehmand , R. Arianfar ,
Volume 20, Issue 2 (9 2007)
Abstract
Background and Aim: An important purpose of adhesive dentistry is restriction of cavity preparation to carious dentin removal and conservation of sound dentin. Application of caries disclosing agents and cavity disinfectants can help achieving this goal. The aim of this study was to evaluate the effect of caries disclosing agents and cavity disinfectants on microleakage of composite resin restorations.
Materials and Methods: This experimental in-vitro study was performed on class V cavities in 48 extracted human sound premolars. The teeth were randomly divided into four equal groups. In group 1 caries detector dye (Seek, Ultradent, USA) and in group 2 cavity disinfectant (Consepsis, Ultradent, USA) were applied on dentinal surfaces. In group 3 both mentioned materials were applied. Group 4 was considered as control group. PQ1 bonding agent and Amelogen composite were used to restore the cavities. Gingival microleakage was assessed by dye penetration. Data were analyzed by Kruskall Wallis and Dunn tests. P<0.05 was the level of significance.
Results: Group 2 showed the least and group 4 showed the highest microleakagehowever no statistical significant difference was found among the groups.
Conclusion: The use of caries disclosing agent (Seek) and cavity disinfectant (Consepsis Liquid) did not adversely affect the sealing ability of dentin bonding resins.
M. Memarian, Mr. Fazeli, H. Jamalifar, S. Karami,
Volume 21, Issue 1 (14 2008)
Abstract
Background and Aim: According to infection possibility in high risk patients, assessment of microbial contamination in water sources utilized at medico-dental units has become a recent concern. The purpose of this study was to evaluate the microbial contamination in dental units waterlines at the department of operative dentistry, Tehran university of medical sciences in the year 2006.
Materials and Methods: In this cross-sectional study, six dental units in the department of operative dentistry were selected to assess microbial contamination in water sources. Samples were taken on Saturdays (the first working day in a week) and in the midweek, 64 and 16 hours respectively after turning the units off. Moreover, for investigating the effect of flushing, sampling was done at 30, 60, 90 and 120 seconds after flushing and were taken from three parts of each unit including air/water syringe, turbine handpiece and also cup filler water. Samples were transported in closed sterile containers to microbiology laboratory of the school pharmacy. Data were analyzed by Kruskal-Wallis and Dunn tests with p<0.05 as the level of significance.
Results: E.coli was isolated from contaminated samples. Contamination decreased by flushing. In midweek after 90 seconds flushing, water contamination disappeared. On Saturdays 2 minutes flushing decreased contamination to lower that 200 cfu/ml (the rate recommended by ADA). Samples taken from turbine handpieces showed significantly higher contamination rate compared to air/water syringe and cup filler water (p<0.001).
Conclusion: According to the results of this study, dental units waterlines showed bacterial contamination which was eliminated after 120 seconds of flushing.
H. Dorriz, M. Memarian, A. Madani, L. Sedighpor, Ar. Shamshiri,
Volume 24, Issue 1 (23 2011)
Abstract
Background and Aims: The aim of this study was to evaluate the effect of zirconia and base metal cores on the color of restorations. Furthermore, the effect of different backings on the color of cercon zirconia was evaluated.
Materials and Methods: The specimens were Cercon zirconia and metal ceramic discs with "high Au" and "base metal" alloys. Cercon zirconia discs were veneered with veneering shade of A2 and two thickness of porcelain (0.7 mm, 1.2 mm). There were 3 discs in each group. Metal ceramic discs were made of "nickel-chromium" alloy (Verobond) and "high Au" alloy (World 89) and two shades (A2, A3.5) and two thicknesses of veneering porcelain. 3 types of backing (high Au, nickel-chromium and A3 shade composite) were made for Cercon zirconia discs. Spectrophotometric evaluation of zirconia discs (on 3 backings) and metal ceramic discs was done. One-way ANOVA and Tukey tests were used for data analysis.
Results: There were no significant differences between the amounts of L*, a*, b* for Cercon zirconia on different backings (P>0.05). In comparison between different core groups, a* was significantly higher in metal ceramic groups compared with that of zirconia groups (P<0.05).
Conclusion: Cercon zirconia can completely mask the underlying backing.
Fahimeh Mokhtari, Amir Mohamad Mahabadi, Naieeme Ghafarian, Alireza Ghate, Alireza Razavi,
Volume 25, Issue 1 (7 2012)
Abstract
Background and Aims: Working length determination and remaining this length is of great importance in root canal therapy. Recently, electronic apex locators are being used to determine working length and decrease the number of radiographs. The purpose of this study was to compare the sensitivity of Root ZX and Novapex electronic apex locators with radiography in a clinical study.
Materials and Methods: In this study, 73 single-canalled teeth of the patients referred to the endodontic department of the Yazd Dental School were evaluated. The access cavity was prepared and working length of the root canals were measured by using the apex locators: Root ZX and Novapex. The file was placed in the root canal and a periapical radiograph was taken using parallel technique. The working lengths obtained by apex locators were recorded and compared with those of radiographs. The data were analyzed by Pearson's correlation coefficient, Wilcoxon test and paired t-test.
Results: The exact measurement without any fault was 46.6% for Root ZX and 20.5% for Novapex compared to radiography. In the range of 0.5 mm fault, the results were 91.8% for Root ZX and 64.4% for Novapex compared to radiographic measurements. The difference between the average of the measured lengths by Root ZX and radiography was not significant (P=0.17). On the other hand, the results showed significant difference between the average of the measured lengths by Novapex and radiography (P=0.017). The difference between two apex locators was not significant (P=0.061).
Conclusion: Root ZX and Novapex with high accuracy are useful for determining working length of the root canals in pregnant patients with special anatomic conditions and patients with muscle disharmony. Therefore, the use of these apex locators combined with radiography is recommended in root canal treatment.
Seyed Amir Hossein Mirhashemi, Razieh Jabbarian,
Volume 27, Issue 2 (6-2014)
Abstract
The need to identify and determine the age of the unidentified dead person s or accident victims of natural disasters is clear. Also, some remedial measures in the field of orthodontics and pediatric dentistry depend on knowing the patient’s physiological age. Previous studies suggested that dental age have a good correlation with physiological age more than skeletal or o ther common methods of age determination. Among the various methods used to determine dental age , dental radiography provides wide facilities for clinicians. Being noninvasive and the ability of performing the technique on live subjects as well as simplicity and low cost and reliable results , have led researchers to investigate further on that . The formation and calcification process of teeth and changes during aging has been regarded by many, leading to introduce various methods in which the field. In this study, 36 related articles were achieved by searching PUBMED, Science Direct and Google Scholar resources and discussed. Provided what diversified means of determining age using dental radiographs is encouraged , it is recommended to be not restricted to use only one of the methods because the multilateral approach is more reliable.
Mehran Bahrami, Maryam Memarian, Farinaz Khodadad Kashi,
Volume 28, Issue 3 (10-2015)
Abstract
Background and Aims: Residual ridge resorption is an unpredictable, unavoidable and time-dependent process which occurs in denture-wearing patients especially those who use mandibular dentures. This process causes more problems in mandible because of its less support, tongue forces and more resorption. Inserting implants in many of these patients requires bone grafts. Overdentures are also more expensive. Denture adhesives are the last option to improve retention and masticatory function in denture-wearers with severe resorption of alveolar ridge. Nowadays only a few denture adhesives are used in Iran and there is not much information about their standard features including, pH, bond strength and washability. The objective of this study was to examine and compare the mentioned characteristics of four denture adhesives (Professional, Corega, Fittydent and Fixodent) and to introduce the most suitable denture adhesive for clinical use.
Materials and Methods: All the methodologies of ISO 10873:2010 were applied. To measure the pH value, 1±0.1g of each denture adhesive was diluted with 5g of propylene glycol and mixed with water. Using pH meter, pH of each group was measured separately for 4 times (n=4) and results were recorded. For the washability test, 4 dentures were fabricated (n=4) and each group of denture adhesives was placed on a denture according to manufacture instructions. For simulating mouth environment specimens were placed in water at 37±2 ̊C bath for 1 hour and then washed with a plastic brush. Specimens were examined for any residual adhesive and the results were recorded. For bond strength test, a sample holder was gently filled with denture adhesives and was attached to the holding arm of bond strength testing device (Santam, STM 20, Iran). Specimens were placed in 300ml water bath at 37±2 ̊C for 10 minutes, and then shaken to be dried and placed in the bond strength testing device. 10N force with 5mm/min rate was applied to the specimen. The force was maintained for 30s and then device arm was pulled back and the highest number was recorded with computer software (Santam Machine Controller v4.19, Iran). The test performed 8 times (n=8) for each adhesive and 8 results were recorded. Data were analyzed using ANOVA test for comparing the bond strength with a significant level fixed
at 0.05.
Results: Professional and Corega adhesives had more neutral pH than that of Fittydent and Fixodent which were more acidic. Washability test showed no remaining mass of any adhesive and there was not any statistically significant difference between groups (P>0.05). Fittydent and Corega adhesives showed higher bond strength than that of Professional and Fixodent and this difference was statistically significant (P<0.05).
Conclusion: Professional and Corega adhesives had less acidity. Thus they cause less harmful effects on the oral mucosa than that of Fittydent and Fixodent and should be indicated in patients with little-tolerant oral mucousa such as diabetous, iron-deficiency anemia and hypertention. All the groups had acceptable washability. Fittydent and Corega had higher bond strength than that of Professional and Fixodent. Therefore in complete-denture-wearers who require more retention as a result of severe ridge resorption, macrotruma, and maladaptiivity, Fittydent and Corega seems to be more acceptable.
Somayeh Zeighami, Marzieh Alikhasi, Maryam Memarian, Moeen Hosseini Shirazi,
Volume 30, Issue 4 (1-2018)
Abstract
Background and Aims: For the clinical success of implant-retained prostheses, fitness of matching components and stability of the applied torque to the implant-abutment assembly under dynamic occlusal loading is essential. The aim of this study was to evaluate the torque loss in Co-Cr castable abutments after cyclic loading.
Materials and Methods: 10 castable abutments were cast in Co-Cr alloy with similar size and height. Each specimen was mounted vertically on a separated implant using a 30 Ncm tightening torque. The detorque values of the abutments were evaluated after 10 min. The same tightening torque was applied to the abutments on their corresponding implants and cyclic loading was applied for 500,000 cycles to the implant-abutment assembly. The torque values after cyclic loading were recorded for each specimen. T-test analysis was conducted on scores from the groups.
Resultes: The results of this study showed that the percentage of torque loss in castable abutments was significantly increased after cyclic loading (P<0.001).
Conclusion: Misfit between the castable implant components can cause torque loss before and after cyclic loading. However, it is more appropriate to relate the results of this study to the screw loosening of the above mentioned abutments than judging their clinical performance.
Mehran Bahrami, Maryam Memarian, Hossein Tamaddon, Mohammad Javad Kharrzi Fard,
Volume 31, Issue 2 (9-2018)
Abstract
Background and Aims: The dentist's attire and appearance affects his/her relationships with the patients. It is also essential to sync the professional attire in dentistry with the habits and Islamic culture of Islamic Republic of Iran, meet the patients' desires, and pay attention to the infection-control-requirements as well.The objective of the present study was to determine the patients' viewpoints about the professional appearance of the dentists at Tehran University of Medical Sciences, Dental School in 1395-96.
Materials and Methods: In this descriptive cross-sectional study, 103 patients (54 females and 49 males) were studied. (=α0.05 and standard variation=4.5). The questionnaire were included color photographies of a female dentist and a male dentist dressed in different attires. The patients were asked to select the cleanest, and the most trustable, competent, and experienced dentist according to the 4 different attires. The frequencies and percentages of the participants’ answers to the questionaire were descriptively reported.
Results: All patients preferred dentists to use white coat during their treatment. For the male dentists, most patients (45.6%) favored simple hair model. For the female dentists, most patients (35.9%) considered veil as the more acceptable Hejaband, and 54.4% of them preferred light makeup.
Conclusion: All patients preferred their dentists to dress in the professional attire with a white coat. They believed that wearing formal-professional-dressing by the dentists may show them look cleaner, and more trustable, more competent, and experienced.
Hoseinali Mahgoli, Habib Hjmiragha, Saied Nokar, Yousef Jafarian,
Volume 32, Issue 2 (10-2019)
Abstract
Background and Aims: Diferences whithin shape and size of hand wrenches in diferent systems could affect the torque applied. Therefore, evaluation of wrenches has been emphasized. The aim of the present study was to compare the torque values of the long and short torque wrenches in different implant systems including ITI, Implantium and Nobel Biocare.
Materials and Methods: In this experimental trial, 5 dentists with at least 5 years of professional experience closed the abutment screw in different implants systems using the long and short manual wrenches while the wrench-induced torque values were calculated by digital torque-meter. Torque application was done for 3 times with 10-minutes resting time between each wrench uses in the habitual closing torque manner. Data were analyzed using two-way analysis of variance test in different implant systems, while the paired comparisons were done using Tukey post hoc test.
Results: The maximum torque values of the long manual wrenches were 27.73±4.57 Ncm, 34.6±8.09 Ncm and 30.6±6.94 Ncm for the ITI, Implantium, and Nobel Biocare systems, respectively. While the values were reported to be 26.4±5.3 Ncm, 35.27±7.94 Ncm and 30.13±5.26 Ncm in the short manual wrenches for the ITI, Implantium and Nobel Biocare systems, respectively. Significant differences were found between ITI and Implantium (P<0.0001), and between Implantium and Nobel Biocare systems (P<0.021). However, no significant differences were observed between ITI and Nobel Biocare systems regarding wrench-induced torque values (P>0.05).
Conclusion: From the results, the torque values obtained by different long and short manual wrenches were specific to different implant systems. These values were less in ITI and Nobel Biocare systems and higher in implantun than those range provided for the implant systems by the companies.
Shiva Shirazian, Sakineh Nikzad Jamnani, Maryam Memarian, Homa Shaghi,
Volume 33, Issue 1 (7-2020)
Abstract
Background and Aims: Due to the very high importance of assessing the clinical performance of students, choosing the best assessment tool and method is one of the most important goals and tasks in medical education. The objective of this study was the development of a checklist for the assessment of dental students’ clinical skills of Tehran University of Medical Sciences, in the clinical complete denture course. The second aim was to determine the validity and reliability of the checklist, and The third aim was the evaluation of raters’ and students’ satisfaction.
Materials and Methods: The checklist was developed in expert panel sessions, and the validity and reliability of the checklist were assessed with CVI (content validity index) test-retest and inter-rater reliability methods, respectively. Students (n=15) were evaluated with a developed checklist. At the end of the session, the satisfaction level of staff and students were assessed. The obtained information was reported descriptively with the expression of mean and standard deviation and in the form of relative and absolute frequencies.
Results: The content validity index (CVI) of the checklist was 0.96. The reliability of the checklist confirmed with a high Intraclass Correlation Coefficient (>0.8) (between 0.82-0.97) (P<0.05). The coefficient of agreement in inter-rater reliability was 0.99 (between 0.991-0.998). Raters’ and students’ satisfaction earned a high percentage of satisfaction.
Conclusion: The designed checklist has the optimal features of a good students’ clinical performance assessment tool; it seems that using this checklist can be an excellent alternative method to a global rating scale to assess the clinical skills of dental students in the complete denture courses.
Rezvan Arian, Namazi, Hanieh Nojedehian, Farhood Najafi, Zahra Yadegari, Roxana Karbaschi, Maryam Torshabi, Sarvin Soleimanpoor,
Volume 37, Issue 0 (3-2024)
Abstract
Background and Aims: Using fissure sealant is one of the most effective methods of preventing pit and fissure decay. Fluoride has been added to various materials as a known anti-caries agent. Fluorinated graphene (FG) has gained attention due to its unique properties. The specific structural characteristics of graphene fillers, besides having antibacterial properties by increasing the rate of fluoride release and charge and neutralizing the acidic pH of the environment, is a suitable option in many treatments. This study investigated the effect of addition of fluorinated graphene nanoparticles on the fluoride release in Fissurit®, a commercial fissure sealant.
Materials and Methods: In this in vitro study, fluorinated graphene oxide (FGO) with bright white color was prepared. After synthesis, 0, 1, 2 and 4 by weight percent were added to the fissure sealant (Fissurit®). Then, the release of fluoride in this material was measured and compared with the commercial fissure sealant containing fluoride (Fissurit®).
Results: According to the obtained results, the amount of fluoride released from groups with different percentages of FGO had a direct relationship with the percentage of FGO addition. Also, at different times, there was a significant difference between the groups with FGO and the control group without FGO (P<0.001).
Conclusion: Addition of FGO to the fluorinated fissure sealant caused the release of fluoride and the possibility of recharging it. The power of releasing fluoride and its recharging in fissure sealant with FGO was higher than the fluorinated fissure sealant, but its fluoride was discharged at a faster rate.
