Showing 10 results for Valizadeh
Ayob Pahlavan, Masumeh Hasani Tabatabaei, Sakineh Arami, Mohammad Ataie, Sara Valizadeh,
Volume 26, Issue 1 (3-2013)
Abstract
Background and Aims: Polymerization shrinkage in Methacrylate-based composite is one of the most important factors in composite restorations failure. Silorane-based composite is introduced to compensate this drawback and claimed to have low shrinkage. The aim of this study was to evaluate the polymerization shrinkage of these two composites.
Materials and Methods: In this experimental study, 5 disk shape samples for each resin composites were placed in the centre of metallic ring bonded to microscopic glass slab. Top surface of ring was covered by a glass cover slip. Glass slab and sample were placed on a special LVDT holder in order to light cure from bottom surface and to measure the polymerization shrinkage. In this study, Deflecting Disk method and LVDT (linear variable differential transducer) was used for dimensional change measurement of resin composites. In this study, two LED curing units were used for composite polymerization.
Results: The mean of polymerization shrinkage in Z250 cured with LED and High Power LED was 11.15±0.08µm and 11.51±0.17µm, respectively (P=0.094), and in P90 cured with LED and High Power LED was 1.08±0.06µm and 1.16±0.12µm, respectively (P=0.019).
Conclusion: Silorane-based composite (P90) showed significantly less polymerization shrinkage than that of methacrylate-based composite (Z250). For the two types of composite, there was no significant difference between the two curing units in polymerization shrinkage.
Zahra Jaberi Ansari, Mahdieh Daneshmonfared, Haleh Valizadeh Haghi,
Volume 27, Issue 1 (4-2014)
Abstract
Background and Aims : In this in vitro study, the long-term bond strength of a self-adhesive resin cement and conventional resin cements to human enamel and dentin was compared .
Materials and Methods: 80 sections of intact human third molars were randomly assigned into eight groups according to the cement type [Rely X Unicem (RXU), Rely X ARC (RXA)], bond substrate (enamel, dentin) and the duration of water storage (24 h or 1 year). Rods of cements (0.75×1 mm) were prepared on the top surface of specimens using Tygon tubes. The micro-shear bond strengths of specimens were measured by a micro-tensile tester. Data were analyzed using Wilcoxon signed ranks and Mann Whitney tests ( α =0.05).
Results: The bond strengths of RXA and RXU cements to enamel after 24h were 18.56±4.08 MPa and 14.99±4.17 MPa, and after 1 year were 19.41±6.24 MPa and 15.51±6.17 MPa, respectively. The bond strengths of RXA and RXU cements to dentin were 13.36±4.02 MPa and 14.16±4.69 MPa after 24h , and 14.63±5.96 MPa and 14.08±6.72 MPa after 1 year, respectively. Tooth substrate had significant effect only on the shear bond strength of RXA cement after 24h (P=0.01), while no other significant differences were found in this study (P>0.05).
Conclusion: According to the results of this study, one-step self-adhesive and multi-step conventional resin cements were similarly effective in bonding to enamel and dentin after 1 year water storage.
Nasim Seyfi, Mahsa Valizadeh,
Volume 29, Issue 4 (1-2017)
Abstract
Background and Aims: Traumatic dental injuries (TDIs) are of the most common dental problems in children and adolescents, which usually occur in the anterior segment and have a significant role in patient’s physical and psychological health. Immediate intervention for damaged teeth can elevate the success rate of treatment in TDI. Thus, general dentists’ knowledge and their effective intervention in TDI are important factors in prognosis of traumatized teeth. The objective of this study was to assess the general dentists’ knowledge and awareness regarding the diagnosis and management of traumatic dental injuries.
Materials and Methods: In this cross-sectional study, the questionnaire data were collected from 130 general dentists, including the demographic data and general dentists’ knowledge about TDIs. The data were analyzed using the Student t-test and Analysis of Variance (ANOVA), Spearman’s and Pearson’s correlation coefficient.
Results: The mean score of general dentists’ knowledge was 8.5 ± 1.5 (total score:10) and it was the same between both males and females (P=0.083). Dentists’ work place does not have any influence in their knowledge (P=0.133). Also, there was no statically significant relationship between the age, job experience and dentists’ knowledge (P=0.805). The relationship between the frequency of TDI managed cases and dentists’ knowledge was not significant (P=0.507).
Conclusion: Considering that the overall knowledge of general dentists regarding the management of TDI was sufficient, it could be a good opportunity in treating these injuries. As TDI is a developing science, it is important to motivate general dentists being up to date regarding this matter.
Siavash Valizadeh, Omid Fatahi Valilai, Alireza Valizadeh, Mahmoud Houshmand, Zahra Vasegh,
Volume 31, Issue 2 (9-2018)
Abstract
Background and Aims: In recent years, the dentistry workflow has developed considerably. By the introduction of computers and their various applications, the effectiveness and efficiency of treatment has increased enormously. Considering engineering concepts in the workflow, it is necessary for participants to assess different steps and data transferring between various software and hardware devices. This research investigated the interaction between dentists, laboratories and production centers through the required steps for accomplishing treatment by different applications of software and digital hardware devices.
Materials and Methods: Review in this article was based on searching Google scholar database considering key words: digital dentistry, workflow, computer aided design and manufacturing, dental CAD/CAM. This search was limited to the English articles published after the year 2000.
Conclusion: It is necessary in dentistry to use digital technologies to improve the efficiency of treatments. Thus, the participants in this field must have appropriate knowledge to choose and apply these tools. Moreover, the participant should help providers of digital solutions for better development of software packages and related hardwares.a
Mehdi Abbasi, Aghil Rahmani, Ladan Ranjbar Omrani, Zohreh Moradi, Masumeh Hasani Tabatabaei, Sara Valizadeh,
Volume 31, Issue 3 (11-2018)
Abstract
Background and Aims: Color is the most important and complicated part of aesthetic dentistry. The tooth color matching of restorations is considered as one of the most difficult tasks in the restorative dentistry. The aim of this study to evaluate the effect of two training methods on the dental students’ ability in determining tooth color matching.
Materials and Methods: In this study, 40 dentistry students participated which randomly allocated into two groups. The first group consisted of students who learned teeth color matching methods practically. In the second group, training booklet was used for learning. Using Vita Classic shade guide series, 4 color samples were chosen and the students of each group were asked to determine samples’ color, before, after and one month after the training.
Results: Booklet learning group was more successful in determining fourth color sample. However, in no studied group and no used samples, the results of one month after learning were not better than that of before learning. Also generally, no significant relationship was found between the color matching accuracy, using glasses, and sex of participants.
Conclusion: The use of booklet learning was more effective than practical learning in color matching accuracy for dental students. Also, using glasses and sex were not effective on their color matching accuracy.
Zohreh Moradi, Masumeh Hasani Tabatabaei, Abolfazl Fateh, Mohammad Javad Torkamani, Ladan Ranjbar Omrani, Sara Valizadeh,
Volume 31, Issue 4 (1-2019)
Abstract
Background and Aims: Methicillin-resistant Staphylococcus Aureus (MRSA) is an important infection source in dentistry for different disinfectants to be used to prevent its transmission. Furthermore, a variety of chemical disinfectants are developed to remove bacterial infections from the dental care workers' hands and claims are made regarding their superiority in infection control, although all requires scientific investigations. The aim of present study was to compare the effects of chemical hand-disinfectants Micro Zed HD, Aseptoman and Decosept on MRSA (methicillin resistant staphylococcus aureus) in different periods of time.
Materials and Methods: In this experimental study, the antibacterial efficacy of three hand-disinfectants on standard strain of MRSA (USA300: ATCC® BAA-1717™) was evaluated according to European standard of evaluating antiseptics (EN 1040:2005 CSN EN). First we prepared a 0.5 Mc Farland (108 CFU/ml) suspension of MRSA, and exposed to three disinfectants for 15, 30, 60 and 90 seconds. Then, they were transferred to separate plates of Mueller-Hinton medium and incubated in 37◦C for 24 hours. The plates were compared then with control plate to evaluate the efficacy of materials on bacteria by calculating the CFU/ml of plates.
Results: Three hand-disinfectants evaluated in this study had the maximum anticabterial effect on MRSA in the minimum time of exposure (15 seconds), and we found no trace of growth in any plates.
Conclusion: The three hand-disinfectans (MicroZed HD, Aseptoman and Decosept) in the concentration suggested by their companies, showed no difference in efficacy to remove MRSA from hands.
Siavash Valizadeh, Omid Fatahi Valilai, Mahmoud Houshmand, Zahra Vasegh, Alireza Valizadeh,
Volume 31, Issue 4 (1-2019)
Abstract
Background and Aims: One of the important fields of dentistry is surgery for dental implants. In this field, dentistry has developed considerably in recent years amongst other fields of medicine from the perspective of digital device and software application. Surgical guides help dental surgeon for more precise, confident, easier and shorter surgery. Process of producing these tools are full digital and to somehow complex due to the application of many technical devices, software and protocols. To achieve efficiency, all participants in the workflow must be aware of all steps and data requirements for production of guides. This paper investigates the production process of surgical guide comprehensively, and also, encompass all the steps in process with details.
Materials and Methods: This review article was based on searching Google scholar and PupMed databases considering key words: Surgical Guide, Guided surgery, digital dentistry, dental CAD/CAM, Additive manufacturing. More than 90% of the references were in English language and published after year 2010.
Conclusion: Today dentistry uses many digital solutions for dairy workflow and most of these solutions are developed by engineers in various fields of knowledge. Thus, this information is essential for dentists, surgeon, clinician and laboratory technician, etc. for better collaboration and participation. Amongst, advances in surgery of dental implant have been highly significant and patients benefit from better treatment and less inconvenience. In addition, dentists do surgery more precise and easier because of considering all conditions before of surgery. Thus, it is substantial inform of all steps of production process.
Sara Mogharrabi, Asadallah Ahmadzadeh, Safoura Ghodsi, Farzad Bazmi, Sara Valizadeh,
Volume 33, Issue 1 (7-2020)
Abstract
Background and Aims: Immediate implant placement following tooth extraction is a treatment with many advantages. Alveolar bone preservation after immediate implant, need minimum of 2 mm thickness in buccal bone plate. The aim of this study was to evaluate the thickness of buccal cortical bone of maxillary premolars by Cone Beam Computational Tomography (CBCT) technique.
Materials and Methods: In this descriptive epidemiological study, Cone Beam Computed Tomography image was obtained from 29 patients (male and female) referred to the radiology department of Jundi Shapoor dental school of Ahvaz from 1393 (Mehr) to 1394 (Shahrivar) for implant insertion insertion. The thickness of buccal cortical bone was measured in 3 and 5 mm apical to the CEJ and root apex, perpendicular to the longitudinal axis. All the measurements were done by two oral and maxillofacial radiologists, separately. Data were analyzed by SPSS22 software, using descriptive statistics, and T-test.
Results: The thickness of buccal cortical bone in second premolar was significantly more than 1 mm (P=0.001), but in first premolar, the thickness was close to 1 mm with a non-significant difference (P=0.29).
Conclusion: The results of this study showed that immediate implant insertion could be done in the maxillary second premolar area with more predictability compared to the first premolar area.
Sara Valizadeh, Ladan Ranjbar Omrani, Zohreh Moradi,
Volume 33, Issue 2 (8-2020)
Abstract
Background and Aims: Enoxolon is a natural licorice and its formula is similar to cortisone. The aim of this double blind randomized match control clinical trial, was to analyze the effect of Arthrodont toothpaste containing 1% Enoxolone on dental plaque, gingival inflammation, and bleeding indices.
Materials and Methods: 40 patients who had gingivitis were selected. They were instructed to brush their teeth twice daily for three minutes then massage the gums with pastes for one minute and then wash their mouths. The patients were divided into two groups: The Arthrodont toothpaste containing Enoxolon, was given to the study group and the Crest toothpaste free of Enoxolon, was given to the control group. At the beginning of the study and after 21 days, plaque, gingival, and bleeding indices were measured. The statistical analyses were done by Paird T test, T test and nonparametrical analysis of Wilcoxon and Mann-Whitney.
Results: In both groups, the three indices decreased significantly. Comparing between the two groups, the gingival and bleeding indices had significantly decreased in the study group (Arthrodont toothpaste) compared to the control group (Crest toothpaste). However, no significance difference in the plaque index between the two groups was found (P=0.143).
Conclusion: The results of this clinical study showed that Enoxolon had anti-inflammatory effect on gingivitis.
Sara Valizadeh, Samaneh I Rezaei Dehnamak, Hamid Reza Khodayar, Ahmad Reza Shamshiri, Zohreh Moradi,
Volume 34, Issue 0 (5-2021)
Abstract
Background and Aims: Due to the review of general dental courses, it was necessary to assess the students' satisfaction with this curriculum. The aim of this study was the assessment level of students’satisfaction with the new educational curriculum of the Ministry of Health at the department of restorative dentistry of Tehran university of medical sciences in 2019-2020.
Materials and Methods: In this descriptive cross-sectional trial,72 sixth year dental students of Tehran University who passed the restorative dentistry courses based on the new curriculum were studied. A questionnaire was developed and for validity content assessment, it was presented to 5 professors and then revised. For reliability approval of the questionnaire, test-retest approach was used. The questionnaire was given to the 30 students of the main pilot group in one session and two-week later and agreement percentage and Kappa index were calculated. After conducting the "test" process and re-testing, the "questions" were statistically analyzed using STATA software.
Results: The most level of satisfaction regarding to practicality of subjects was found for fundamental of restorative dentistry including principles of amalgam class I cavity preparations and restorations on the dentic (81.94% and 76.39% acceptable respectively) and the principles of amalgam classII cavity restorations on the dentic (72.22%). The least satisfaction levels were obsereved in the first and second theoretical restorative courses including tooth-colored restorations (47.22%), onlays and inlays (47.22%) and tooth-colored classII cavity preparations and restorations (48.61%). The amount (P-value or error of the first type) was reported in all questions>0.001.
Conclusion: Despite the limitation of this study, final-year dental students’ satisfaction of theoretical restorative dentistry courses was medium, while it was high for the fundamental and practical restorative courses of 2017 educational curriculum.
