Showing 17 results for Azari
A Azari ,
Volume 10, Issue 2 (8 1997)
Abstract
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AR-SA Adhesive restorations have been introduced to
dentistry for almost 3 decades and it could be stated that from that time there
has been lots of ups and downs until emersion of current restorations. What was
focused the most at the time of introducing these restorations was their long
lasting estimated strength which has undergone many studies and now everyone is
aware of their advantages and disadvantages. Although their real adhesion to
teeth is still ambiguous and wide researches on biomechanics of oral cavity and
the relation with adhesive restorations are in process. This article is aimed
to present a novel method for preparation of metal surface. In first part, the
process of research is explained and in two following parts the process of new
method evolution and theoretic principles are mentioned. Finally, there is a 7
year report of clinical cases using new method.
A. Azari ,
Volume 12, Issue 2 (9 1999)
Abstract
After approximately 40 years of experience in the field of resin - bonded restorations (R.B.R),these restorations arc one of the most controversial. During these years, many suggestions have been made for better performance and increasing durability of these restorations. The aims of this paper are:1 - Reviewing the literature for the so many factors involving the success or failure of R.B.R.2 - Introducing a new and simplified method for increasing the durability and /or relention of R.B.R.
S. Zarrati , M. Nazari Marzjarani ,
Volume 15, Issue 2 (8 2002)
Abstract
Esthetic is a natural necessity among all human beings, and the reconstruction of the natural features of prosthesis is considered an important aspect in dentistry. Reconstruction of the natural features in removable prosthesis by characterization of denture base is one of the most important factors. In this regard esthetic, in removable prostheses, is achieved through different techniques such as: tooth selection and arrangement, designing the denture base and acrylic base color. The final goal for ail these effects is to achieve a natural appearance for denture. However, other factors such as treatment limitations, different personal needs and general health principles, should be taken into consideration. This article not only reviews the natural appearance of oral mucosa that is replaced by the denture base, but also discusses about the materials used in tinting acrylic denture base and their application techniques.
R. Sadeghi , K. Nazari Moghaddam , J Jooyandeh ,
Volume 17, Issue 3 (7 2004)
Abstract
Statement of Problem: There is a controversy about the relationship between pulpal and periodontal diseases. The interrelationship between pulp and periodontium could have an important effect on the treatment plan of the tooth.
Purpose: The aim of the present research is to evaluate root canal therapy effects on periodontal healing of teeth with chronic advanced periodontitis.
Materials and Methods: In this randomized controlled clinical trial 32 single rooted teeth which had necrotic pulp or irreversible pulpitis in 7 patients with chronic advanced periodontitis were selected based on specific criteria. Using a split mouth design, teeth were randomly put in two groups of test and control. In the test group root canal therapy ,scaling & root planing were done.In the control group, only scaling & root planing were performed. Clinical parameters including Pocket Depth (PD), Clinical Attachment Level (CAL), mobility, pattern of bone destruction and plaque index (PI) were evaluated in two groups at base line, 1 and 3 months after treatment. Appropriate tests such as paired Wilcoxon and Mann-Whitney were performed.
Results: Statistically significant reductions were found in the test group when comparing baseline and one-month post treatment values for Clinical Attachment level (CAL) but not after 3-months. In the control group the CAL reductions were not statistically significant between baseline and one month post-treatment, but a increase were observed between one month and three months after treatment. There was a statstically significant difference between the test and the control groups. Other parameters didn’t show any significant differences in each group and between two groups.
Conclusion: Since clinical attachment level was the most important parameter we found it can high lighted the role of pathogene with pulpal origin in progression of periodeontal disease and it is concluded that beside periodontal treatment in some advanced periodontal cases pulp therapy maybe an effective procedure for eleminating destructive pathogens of pulp and causing periodontal healing.
Hr. Abdolsamadi , Sh. Nazari , F. Mirmotalebi , M. Shirinzad ,
Volume 19, Issue 3 (4 2006)
Abstract
Taurodontism is a rare dental anomaly in which the involved tooth has enlarged and elongated body and pulp chamber with apical displacement of the pulpal floor. Endodontic treatment of these teeth is challenging because it requires identifying the number of root canals. A case of bilateral involvement of maxillary first molar teeth is presented. Endodontic treatment of the right maxillary first molar with taurodontism was indicated due to irreversible pulpitis. In this article, we described the procedure of root canal therapy for this case.
A. Azari, S. Nikzad, F. Geramipanah, H. Mahgoli, L. Sedighpor,
Volume 21, Issue 3 (8 2008)
Abstract
Amelogenesis imperfecta is an inherited disease that disturbs the formation of the enamel. It occurs as two main categories, hypomineralized and hypoplastic. Both deciduous and permanent teeth are affected, and the disorder may create unaesthetic appearance, dental sensitivity, and severe attrition. In this article through performing a structured literature review, numerous treatment modalities which so far advocated in rehabilitation of amelogenesis imperfecta in adults and children is discussed. The progressive changes on open bite, the problem of bonding during restorative phase of treatment , the rehabilitation difficulties of deciduous as well as permanent teeth is also discussed in detail and finally the interdisciplinary approach for treatment of this disability is demonstrated and some points for decision making in treatment protocols are suggested.
S. Nikzad, A. Azari, M. Khosravi, A. Nezadi,
Volume 21, Issue 3 (8 2008)
Abstract
Background and Aim: By definition, pontic is an artificial replacement of missing tooth (teeth) which is essentially used to establish function and esthetics. In order to this fact that, pontic(s) is not completely the same as tooth (teeth) to be replaced, it may not be concern as a simple type of restoration to achieve the best result, it must be design from the esthetically and hygienically point of view as well as comfort, demand and tissue health of patient. The main purpose of this study is to investigate the pontic designs and their relationship to edentulous partial aras.
Materials and Methods: 73 pontics in 57 patients have been included in this cross-sectional study. These patients were under treatment in the department of prosthodontics. A primary cast was achieved from each patient and then the cross-sectional contour of edentulous ridge was depicted. For each patient the type of pontic design was derived from textbook standards and then compared with the design of actual verified Prosthesis at delivery. The shape of tissue surface of each denture was determined by a low viscous impression material. The result of each comparison was recorded in a chart data set.
Results: The most common pontic design was Modified ridge lap with frequency of 93.2%. The type of ridge was %45.2 normal, %19.2 class I, %8.2 class II and %27.4 class III, respectively. %72.6 of pontics tested have inappropriate design in tissue surface.
Conclusion: It seems that in a high percentage of cases the tissue surface contour of prescribed pontics in department of prosthodontics was incorrect and more attention must be paid to the education of students and technicians.
S. Nikzad, A. Azari, H. Bashizade Fakhar,
Volume 22, Issue 1 (11 2009)
Abstract
It is quite often for general practitioners who want to use implants in their routine treatments to face with the problem of unfamiliar radiographic techniques commonly prescribed in modern implantology. These types of radiograph, which could show the jaws in multiple aspects, are not routinely used by general practitioners. However, for sophisticated very delicate treatment options like implantology, the main problem is that "a metal object want to be placed in an undercut-full and zigzag area like bone", and the so called plain radiographs cannot be used for this purposes without difficulty. In this literature review, based on the data of the most powerful databases including COCHRANE and PUBMED, the necessity of using cross-sectional techniques in pre-implant treatment discussed in detail.
S. Nikzad, A. Azari,
Volume 23, Issue 1 (22 2010)
Abstract
Surgical and prosthodontic implant complications are often the case of inadvertent improper diagnosis, planning, and placement. These complications always pose a significant challenge in implant dentistry. In this article, it is attempted to depict a new technique in which advanced software program along with newly developed CAD/CAM technology called rapid prototyping will be used. This technology permits graphic and complex 3D implant simulation and then fabrication of computer-generated surgical templates. The best position of implants planned at first by taking into consideration of encased bone density of each implants and then existing occlusion. In this paper, the evolution of Computer Guided Implantology and the many benefits achieved from this very sophisticated technology described as a literature review.
Hr. Rajati Haghi , S. Nikzad , A. Azari , J. Kashani ,
Volume 23, Issue 2 (23 2010)
Abstract
Background and Aims: Freestanding fixed partial prosthesis is considered the first choice whenever possible. However, anatomical limitations for implants and other reasons may create situation in which it would be preferable to connect the implants to teeth. A biomechanical dilemma in a tooth/implant-supported system comes from dissimilar mobility. This disparity cause the bridge to function as a cantilever and a series of potential problems such as osseointegration loss, screw loosening arise. The aim of this study was to analyze the tooth-implant supported bridges in rigid/non-rigid connectors in cemented prostheses using finite element stress analysis.
Materials and Methods: In this study four three-dimensional models were simulated by use of Solid works software. These models are: 1-RCCP: rigid connector between tooth and implant, 2-NRC CP1: non-rigid connector at mesial side of implant, 3-NRC CP2: non-rigid connector at distal side of second premolar, 4-NRC CP3: non-rigid connector at the middle of pontic, The stress values of four models loaded with vertical forces (150 N) were analyzed.
Results: The maximum stress concentration was located at the crestal bone around implant and stress distribution was more balanced around the teeth except in the model of NRCCP2. Stress distribution was imbalanced in non-rigid connection especially in the NRCCP1 model. The presence of non-rigid connector in bridge increases the stress values in suprastructure and transfers to the adjacent structures. Conclusion: The tooth-implant supported prosthesis should be considered as a valuable prosthetic option. It could be suggested that if tooth and implant abutments are to be used together as fixed prostheses supports, rigid connector is the choice because the prosthesis and implant possess the inherent flexibility to accommodate dissimilar mobility characteristics.
Sakine Nikzad, Abbase Azari, Mohamad Ehsan Khalil, Poya Aslani, Sima Shahabi,
Volume 24, Issue 4 (28 2012)
Abstract
Background and Aims: Reliable bonding between tooth substrate and zirconia-based ceramic restorations is always of great importance. The laser might be useful for treatment of ceramic surfaces. The aim of the present study was to investigate the effect of laser irradiation on the shear bond strength of zirconia ceramic surface to dentin.
Materials and Methods: In this experimental in vitro study, 40 Cercon zirconia ceramic blocks were fabricated. The surface treatment was performed using sandblasting with 50-micrometer Al2O3, CO2 laser, or Nd:YAG laser in each test groups. After that, the specimens were cemented to human dentin with resin cement. The shear bond strength of ceramics to dentin was determined and failure mode of each specimen was analyzed by stereo-microscope and SEM investigations. The data were statistically analyzed by one-way analysis of variance and Tukey multiple comparisons. The surface morphology of one specimen from each group was investigated under SEM.
Results: The mean shear bond strength of zirconia ceramic to dentin was 7.79±3.03, 9.85±4.69, 14.92±4.48 MPa for CO2 irradiated, Nd:YAG irradiated, and sandblasted specimens, respectively. Significant differences were noted between CO2 (P=0.001) and Nd:YAG laser (P=0.017) irradiated specimens with sandblasted specimens. No significant differences were observed between two laser methods (P=0.47). The mode of bond failure was predominantly adhesive in test groups (CO2 irradiated specimens: 75%, Nd:YAG irradiated: 66.7%, and sandblasting: 41.7%).
Conclusion: Under the limitations of the present study, surface treatment of zirconia ceramics using CO2 and Nd:YAG lasers was not able to produce adequate bond strength with dentin surfaces in comparison to sandblasting technique. Therefore, the use of lasers with the mentioned parameters may not be recommended for the surface treatment of Cercon ceramics.
Sakineh Nikzad, Abbas Azari, Mani Arashrad, Ghazal Arashrad,
Volume 26, Issue 1 (3-2013)
Abstract
Background and Aims: The marginal integrity of fixed restorations always is a major matter of concern for dental clinicians. Any cause of distortion, including veneering processes, in the marginal integrity is supposed to be detrimental for long-term success of fixed dental prostheses. The aim of this in vitro study was to compare the marginal adaptation of two different full ceramic restoration systems (Zirkouzahu&Cercon) and possible changes in marginal integrity following the multiple veneering process.
Materials and Methods: Twelve all-ceramic crowns in the form of coping were fabricated on a pre-made standard metal die with finish line of shoulder preparation from two commercial systems: Cercon® and Zirkonzahn®. The specimens were not cemented. The Crown/Die discrepancy were measured by means of a precise stereo microscope (accuracy±0.1 μm), at various points (n=12) selected along circumferential margin of the restorations. Same procedure was accomplished after applying the veneering porcelain. The mean gap dimensions were calculated and data were analyzed by multivariate (b) test.
Results: Mean marginal gap dimensions before and after veneering porcelain firing cycles, for Cercon® were (59.67±13.46 µm) and (63.75±14.16 µm) and for Zirkonzahn® were (65.81±24.37 µm) and (64.74±21.94 µm), respectively. Hotelling trace Multivariate(b) test method showed that the rate of mismatching marginal integrity in two groups (Cercon® and Zirkonzahn®) had no significant difference before and after porcelain firing (P>0.05).
Conclusion: Within the limitation of this study, the marginal integrity of both systems were seems to be within the clinically acceptable standard dimension, i.e. 120μm.The marginal gap of both all-ceramic systems were not affected by veneering porcelain firing cycles.
Mahshid Mohammdi Basir, Elham Tabatabai Ghomsheh, Abbas Azari, Zahra Malek Hosseini, Majid Vahdati Far,
Volume 26, Issue 2 (5-2013)
Abstract
Background and Aims: Endodontically treated teeth are prone to fracture because they loose a big amount of their structure. The treatment plan of those teeth is completed when they are rehabilitated with a strong and functional restoration. The purpose of this study was to evaluate the fracture resistance of endodontically treated teeth restored with amalgam cuspal coverage in comparison with other restorative techniques.
Materials and Methods: 40 human healthy maxillary premolars were divided into 4 groups: group1 (S): sound teeth, group 2(Co): endodontically treated teeth with MOD cavity restored with bonding and composite, group 3(Am-B): endodontically treated teeth with MOD cavity restored with bonding and amalgam and group 4 (Am-CC): endodontically treated teeth with MOD cavity restored with amalgam cuspal coverage. Then the restorations were stored in water and room temperature for 100 days at then thermocycled for 500 cycles between water baths at (5.5 ± 1) and (55 ± 1) 0 C. The fracture resistance was evaluated by universal testing machine (Instron, 1195 UK) with the compressive force of about 2000 N in 0.5 mm/min. The fracture modes were evaluated in four groups by a stereomicroscope. Statistical analysis (Scheffe test) was done for all groups (P<0.05 was considered as the level of meaningfulness).
Results: The highest fracture resistance was found in group 4 (Am-CC) (976 ± 23.27 N) that had no significant difference with sound tooth (P>0.05). The lowest fracture resistance was found in group 2 (Co) (384 ± 137.4 N) that had no significant difference with group 3 (Am-B) (P>0.05). The fracture resistance in group 4 was significantly higher than group 2 (Co) and 3 (Am-B). The fracture mode in group 1 was cohesive within tooth and in group 2 (Co) and 3 (Am-B) was mixed cohesive and adhesive, and in group 4 was cohesive within in restorative material.
Conclusion: The highest fracture resistance was found in teeth that received amalgam cuspal coverage.
Mohammad Ebrahimi Saravi, Yushiaho Refoa, Yunes Nazari Dashlibrun, Reza Sharifi,
Volume 26, Issue 4 (1-2014)
Abstract
Background and Aims: Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to root resorption of the adjacent tooth. The purpose of this study was to determine this resorption using panoramic and periapical radiographs.
Materials and Methods: In this cross-sectional descriptive study 54 patient (28 men, 26 women) above 15 years old with the average of 22 years in Oral and Maxillofacial Department of Tehran University were studied. A periapical radiography from the third molar and a panoramic radiograph were taken from each patient (Because of their routine use and evaluation of accuracy of panoramic compared with periapical), and the magnitude of the root resorption for the second molar was determined by 2 observers and written in a questionnaire. Data were analyzed using Fisher test.
Results: The prevalence of the root resorption of the second molar adjacent to the impacted third molar in the panoramic and the periapical radiographies, with respect to the limitation of the sample size were 46.3% and 31.5%, respectively, with 95% confidence(P>0.05). Most of these resorptions were in the cervical third of the second molar roots and in cases in which the third molars were mesially oriented or horizontal. There was also no significant difference between panoramic and periapical radiographs.
Conclusion: Due to the increased risk of the resorption of the second molar adjacent to the third molar, extraction of the impacted third molars, especiall y mesially oriented or horizontal ones are recommended.
Sakineh Nikzad, Abbas Azari, Somayeh Niakan, Zeynab Bahrani,
Volume 27, Issue 3 (9-2014)
Abstract
Background and Aims: The aim of this review article was to present the information have been published, regarding the functional properties of Zirconia until today.
Materials and Methods: A review of the literature was carried out in MEDLINE database using key words (Dental ceramic, Zirconia, 3Y-TZP, Clinical performance, Machining and Transformation toughening). These searches were limited to the articles published after the year 2000.
Conclusion: Despite excellent clinical results in short-term studies, there is still a major need to have more clinical and laboratory long-term information about zirconia restorations.
Majid Sahebi, Marzieh Alikhasi, Farshad Movafegh, Vahideh Nazari,
Volume 29, Issue 1 (7-2016)
Abstract
Background and Aims: In response to esthetic demand and use of zirconia abutments; detection of implant-abutment connection misfit is so important. The purpose of this study was to evaluate the sensitivity and specificity of radiographic images in the detection of abutment-implant connection misfit in zirconia and titanium abutments of three different implant connections.
Materials and Methods: One regular implant fixture of Branemark, Noble active and Replace systems were mount in acrylic models. Two pieces titanium and zirconium abutments were attached to the implants, once with correct adaptation and once with 0.5 mm spacer. Digital radiographic images were taken of 12 created states with zero degree vertical and horizontal inclination and evaluated by 10 specialists in implant treatment in two different time penods. Data were analyzed using Kappa analysis.
Results: Interclass Correlation Coefficients (ICC) of the agreement of answers in the first and second times were 97.4 and 97.5, respectively (P<0/001). Sensitivity of detecting gap in all groups was acceptable (95-100%) except titanium abutment in Noble active which was the lowest value (35%). Specificity of all groups were acceptable (80-95%) except zirconia abutments in Noble active and Replace with 45% and 30% values, respectively, and titanium abutments in Branemark had the highest value (95%).
Conclusion: The sensitivity of radiographic images in detection of abutment-implant connection misfit only in Noble active with titanium abutment was not acceptable. Specificity of radiographic images in the absence of gap in titanium abutments was more favorable.
Mohammad Javad Etesami, Seyyed Lotfollah Derakhshan, Kiomars Nazari Moghadam, Mohammad Ebrahimi Saravi,
Volume 29, Issue 1 (7-2016)
Abstract
Background and Aims: Cleaning and shaping is one of the most important stages in endodontic treatment. Single-file systems save time and reduce the risk of transmission of pathogens. This in vitro study was aimed to compare the rate of canal transportation after the preparation of the stimulated resin root canal with two single-file systems, namely Waveone and Reciproc.
Materials and Methods: Thirty stimulated resin root canal blocks with size 8/0. 02 K file were randomly divided into two study groups. The preparation in Group A and Group B was performed using Reciproc and Waveone files, respectively. Pre and post- preparation photographs were taken and the images were superimposed to evaluate the inner and outer wall’s curvature tendency at three points (apical, middle and coronal) using AutoCad pragram. Data were analyzed using T-test.
Results: Based on the results, the degree of transportation in the inner and outer walls of the canal was less at the level of 3 millimeters (P<0.001) and there was no significant difference between the two groups regarding the deviation at the levels of 1 and 5 millimeters (P>0.05).
Conclusion: Waveone showed better performance in the middle third of canal and this system maybe recommended.
