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فهرست مطالب نویسنده:

marzieh alikhasi

  • Ali Mahmoud Hashemi, Mahya Hasanzadeh, Ameen Khraisat, Marzieh Alikhasi
    Objectives

    This study aimed to do a comprehensive systematic review on the comparison of digital and conventional workflows regarding prosthetic outcomes, accuracy of implant impressions, framework passivity and fit, and clinical fabrication of multi-unit implant-supported fixed restorations.

    Materials and Methods

    The EMBASE, PubMed, Scopus, and Cochrane Library databases were searched for relevant articles published up until April 2020.

    Results

    No in-vivo article was found to compare full digital and conventional workflows regarding the accuracy of implant impressions, passivity and fit of frameworks, and prosthetic outcomes. There was no study to investigate full digital and conventional workflows for clinical fabrication of multi-unit implant-supported fixed restorations.

    Conclusion

    This empty review highlights the need for further research to compare full digital and conventional workflows for implant-supported restorations.

    Keywords: Dental Prosthesis, Implant-Supported, Computer-Aided Design, Review
  • Ali Mahmoud Hashemi *, Mahya Hasanzadeh, Leila Payaminia, Marzieh Alikhasi

    Statement of the Problem: 

    Some components of implant treatment are reusable. Therefore, possible changes during fixation, removal, and sterilization process should be tested. Many studies have examined the reuse of implant parts, but the impact of repeated use of scan bodies on the accuracy of implant position has not been well investigated.

    Purpose

    The aim of this in vitro study was to compare the effect of repeated use of two different types of scan bodies on the accuracy of implant position.

    Materials and Method

    In this in vitro experimental study, two acrylic resin maxillary models, each with two implant analogues inserted at the site of missing first and second molars were used. Two types of scan bodies including titanium and polyetheretherketone (PEEK) were used for digital impression. Then they were ten times removed and autoclaved for sterilization. The first scan was considered as a reference to be compared with the other next nine scans. Values of linear distance between two scan bodies, diameter changes of each scan body, and three-dimensional linear displacement (ΔR) were measured. These values were compared between the two types of scan bodies using t-test (α=.05). 

    Results

    There was significant difference between titanium and PEEK scan bodies regarding inter-implant distance variation (p=.006) and diameter change (p< .001) in repeated use. However, for the ΔR, there was no significant difference between them (p= 0.759).

    Conclusion

    The results demonstrated that type of scan body could affect the accuracy of implant position transfer after repeated use. PEEK scan body performed better after 9 cycles of reuse in comparison with titanium scan body.

    Keywords: Computer aided design, Computer aided manufacturing, Dental Prosthesis, Implant supported, Impression technique
  • Marzieh Alikhasi, Zahra Jafarian *

    Interim restorations are essential in many clinical scenarios in which indirect restorations are administered. Additional manufacturing (AM) technology has recently been introduced and applied in different fields of dental practice. This study aimed to collect relevant information from published papers regarding different aspects of AM temporary restorations with a focus on the most relevant technical properties. An electronic search was performed on Medline/ PubMed/ Scopus databases up to April 2020 to find relevant, peer-reviewed articles about AM provisional restoration. Although promising results for AM temporary restorations were obtained, comprehensive application of this technology in making provisional restorations requires information to address the missing properties concerning the short time of application.

    Keywords: Computer-Aided Design, Stereolithography, Digital technology, Prosthodontics
  • Hesan Shafaei, Marzieh Alikhasi*
    Introduction

    Screw loosening is the most common technical complication in cement-retained dental implants. To retrieve screw loosened dental abutment, making abutment screw channel (ASC) is a useful method to access the abutment screw. This article reviews the methods for preparing ASC of cement-retained implant supported restoration.

    Materials and Methods

    The search was conducted on PubMed, Google Scholar, and Scopus. The keywords were screw loosening, cement-retained implant restoration, screw access hole, abutment screw channel and retrieving.

    Results

    Having applied the inclusion and exclusion criterion, 24 articles, 21 technical notes, 1 case report, and 2 reviews were found.

    Conclusion

    The techniques reviewed were categorized into 3 groups of marking techniques, customized guides, and imaging techniques with different outcomes.

    Keywords: Abutment screw channel, Cement-retained, Implant restoration, Retrieving, Screw loosening, Screw access hole
  • Safoura Ghodsi, Marzieh Alikhasi, Majid Sahebi, Vahideh Nazari
    Objectives

    This study aimed to investigate the marginal adaptation of implant-supported three-unit fixed restorations fabricated in excessive crown height by various frameworks namely zirconia, nickel-chromium (Ni-Cr) alloy, and Polyetheretherketone (PEEK) before and after veneering.

    Materials and Methods

    A basic model with two implant fixtures was made to receive posterior three-unit fixed partial dentures (second premolar to second molar) in 15 mm crown height. A total of 30 frameworks were fabricated using Ni-Cr, zirconia, and PEEK (n=10). All specimens were veneered and vertical marginal discrepancy was evaluated before and after veneering using a stereomicroscope (×75). The effect of framework material and veneering on marginal discrepancy was evaluated by repeated-measures and one-way ANOVA, and paired t test (α=0.05).

    Results

    There was a significant difference between the groups (P<0.001) before and after veneering. The vertical marginal discrepancy of zirconia frameworks was significantly lower than that of other groups both before and after veneering (P<0.001). Statistical analysis revealed that the veneering process had a significant effect on marginal adaptation (P<0.001).

    Conclusion

    In implant prostheses with excessive crown height, zirconia had the greatest marginal adaptaion significantly, followed by Ni-Cr. Veneering caused a significant increase in marginal discrepancy of all the materials.

    Keywords: Dental Marginal Adaptation, Dental Veneers, Polyetheretherketone, Zirconium Oxide
  • Safoura Ghodsi, Anahita Fayyazi, Maryam Ghiasi, Ahmad Rohanian, Marzieh Alikhasi*
    Objectives

    Implant-supported restorations are generally used for the replacement of the lost teeth. Stability against masticatory forces and proper retention are critical for optimal durability of restorations. The aim of this experimental study was to compare the retention of cobalt-chromium (Co-Cr) copings made by different techniques.

    Materials and Methods

    Twenty-four solid abutment analogs were mounted and scanned with a desktop scanner. They were divided into two groups (n=12) and received metal copings fabricated by either soft or hard Co-Cr alloy. Soft Cera mill Sintron Co-Cr patterns were milled and sintered. Hard Co-Cr blocks were milled in a milling machine. The copings were sandblasted, polished, adjusted, and placed on the respective abutments. The frequency of adjustments was recorded for each abutment. The copings were cemented with zinc phosphate cement and underwent tensile test by a universal testing machine. The Mann-Whitney test and t-test were used to compare the two groups (α=0.05).

    Results

    There was no significant difference in retention of copings between the experimental groups. The mean retentive force was 559.58±115.66 N and 557.13 ±130.48 N for the soft and hard metal groups, respectively (P=0.96). Considering the non-normal distribution of adjustment frequency data, the Mann-Whitney test showed that the frequency of adjustments was significantly higher in the hard metal group than the soft metal group (9.5 versus 0.1667; P<0.001).

    Conclusion

    Although hard metal copings required more adjustments, retention of soft and hard Co-Cr copings was not significantly different.

    Keywords: Computer-Aided Design, Dental Implants, Dental Prosthesis Retention, Hard Metal
  • Noushin Shokouhinejad, Marzieh Alikhasi, Mehrfam Khoshkhounejad*, Asma Pirmoazen
    Background

    The aim of this study was to assess the discoloration of coronal tooth structure irrigated with different irrigation solutions and filled with calcium silicate‑based materials containing bismuth oxide or calciumzirconia complex as radiopacifier.

    Materials and Methods

    In this ex vivo study, 72 bovine enamel‑dentin blocks were prepared and divided into three groups. The dentinal cavities in each group were irrigated with 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), or normal saline for 30 min. After that, irrigation solutions were removed using a cotton pellet. Each group was then randomly divided into two subgroups according to the cavity‑filling materials (ProRoot mineral trioxide aggregate [MTA] and RetroMTA). The color assessments were performed before filling the cavities and 1 month and 6 months after filling the cavities. Data were analyzed with two‑way ANOVA. The level of statistical significance was set at P < 0.05.

    Results

    The effect of irrigation solution on the color change of calcium silicate‑based materials was not statistically significant at none of the time intervals (P = 0.334 and P = 0.252, respectively, for ProRoot MTA and RetroMTA). ProRoot MTA caused a significantly higher color change compared with RetroMTA exposed to different irrigation solutions at each time interval (P < 0.001). Color change of both materials exposed to each irrigation solution significantly increased over time (P < 0.05).

    Conclusion

    Under the condition of this ex vivo study, irrigation of dentin with NaOCl and CHX and then removing the excess solution might be ineffective in increasing the tooth color change potential of either bismuth oxide or zirconium‑containing calcium silicate‑based materials. Furthermore, calcium silicate‑based material, which contained bismuth oxide, caused higher tooth discoloration.

    Keywords: Calcium silicate, chlorhexidine, mineral trioxide aggregate, root canal irrigant, sodium hypochlorite, tooth discoloration
  • Arash Khojasteh, MohammadMehdi Dehghan, Saeed Reza Motamedian, Saeed Farzad-Mohajeri, Pantea Nazeman, Golnaz Morad, Hanieh Nokhbatolfoghahaie, Marzieh Alikhasi
    Introduction

    Mesenchymal stem cells (MSCs) have been utilized as an aid in regeneration of bone defects however due to the poor homing ability via systemic injection, local administration, genetic manipulation has been used more. The present study aimed to compare the local and systemic application of MSCs in regeneration of bone defects.

    Materials and Methods

    Sixty Wistar male rats were used in this study. Circular 5×5 mm bone defects were created in the angle of the mandible. Autogenous bone marrow mesenchymal stem cells (BMMSCs) were obtained and culture expanded. Green fluorescent positive (GFP+) transfection has been performed for the possible detection of the cells in the healed bone. The rats were randomly treated in four groups; 1. Beta tricalcium phosphate (β-TCP) scaffold seeded with MSC (β-TCP+MSC), 2. Intravenous MSC injection with β-TCP scaffold in the defect (MSC), 3. β-TCP without cell therapy (β-TCP) and 4. Control defects that left empty. The rats were euthanized after 8 weeks. New bone formation (BF) were investigated by hematoxylin and eosin staining.

    Results

    Localized cell therapy (β-TCP+MSC group) showed the highest healing rate (BF= 54.05±2.39%) followed by MSC systemic injection (BF= 22.69±3.87%) (P≤0.05). Inflammatory cells infiltration was evident dominantly in systemic injection cell group. Immunohistchemical analysis showed existence of the MSCs around the defects. GFP+ cells were mainly detected in the defect in β-TCP+MSC group while few GFP+ cells were detected in the MSC systemic group.

    Conclusion

    local application of the MSCs with synthetic scaffold showed better results than intravenous administration of MSCs in treatment of rat mandible bone defects.

    Keywords: Mesenchymal stem cells, Bone regeneration, Regenerative medicine, Tissue Engineering
  • Vahideh Nazari, Marzieh Alikhasi*
    Introduction

    Amelogenesis imperfect (AI) refers to a group of autosomal dominant disorders primarily affecting the enamel and can present a variety of clinical appearances. This report describes a multidisciplinary approach for oral rehabilitation of a young man patient with hypoplastic AI with severe skeletal anterior open bite (AOB).

    Case Report

    A 22-year-old male patient was presented with compromised masticatory efficiency and dissatisfaction with his teeth appearance. Based on the clinical and radiographic examination, the patient was confirmed as AI (hypoplastic type) with severe AOB. The treatment included orthognathic surgery (Le Fort I osteotomy and genioplasty) for correcting AOB, long face, and limited space in the posterior region, followed by crown lengthening and prosthetic rehabilitation. Before surgery, a mock-up of all teeth was performed to facilitate alignment and stabilization of the dental arches during the Le Fort I osteotomy.

    Results

     Solid tooth interdigitation that provided with mock-up, helped to adjust the stable skeletal position of the maxilla during the surgery.

    Conclusion

     preoperative mock-up appears to be an efficient fixation option to achieve an acceptable occlusion after prosthetic rehabilitation in AI patients with severe AOB.

    Keywords: Amelogenesis imperfecta, Open bite, Orthognathic surgery, Dental prosthesis
  • Vahid Khoshkam *, Guo-hao Lin, Marzieh Alikhasi, Homayoun H. Zadeh
    Introduction

    Multiple systematic reviews have documented the efficacy of short implants in alveolar sites with moderate vertical height atrophy. Short implants in sites with alveolar ridge atrophy are often restored with elongated restoration, leading to relatively high crown-to-implant (C/I) ratio. It is important to determine whether the increased C/I ratio has any detrimental biological effects on peri-implant bone. To that end, this systematic review sought to examine the long-term effects of C/I ratio on peri-implant marginal bone loss, as reported by prospective clinical trials.

    Materials and Methods

     Electronic search of 3 databases and hand searching were performed to identify prospective human trials that had reported both crown/implant ratio and associated peri-implant marginal bone loss with the follow-up of at least 36 months. Random-effect meta-analysis was performed to analyze weighted mean difference (WMD) and confidence interval (CI) for recorded variables according to PRISMA guidelines. Weighted linear regression model was used to evaluate R2 value.

    Results

     Publication search yielded 1134 records and after evaluating titles, abstracts and full-texts, 8 prospective trials were included for quantitative data synthesis. Meta-analysis for the comparison of MBL among selected studies showed a WMD of 0.01 mm, with a 95% CI= 0.08 mm to -0.07 mm (p= 0.90). Results failed to detail any significant correlation between C/I ratio and marginal bone loss. Weighted linear regression model and low (0.214) R2 ratio suggested a lack of correlation between MBL and C/I ratio.

    Conclusion

     Basad on the available evidence, there is no relationship between C/I ratio within the range tested and marginal bone loss.

    Keywords: Systematic Review, Evidence-based Dentistry, Short Dental Implants
  • Sareh Habibzadeh, Marzieh Alikhasi *, Arash Khojasteh

    Allogeneic bone graft has been suggested to be a quite propitious alternative bone substitute to autograft. However, controlled clinical trials with adequate samples, including meticulous bone gain measurements, histological evaluations, and long-term clinical and radiographic assessments of inserted dental implants have not yet been conducted to evaluate the abovementioned assumption. This case report presents a patient for whom allogeneic bone block grafting with a guided bone regeneration procedure had been performed in order to improve the horizontal dimension of atrophic maxillary edentulous ridge. Following an uneventful 8-month healing period, though not obvious clinically, tomography images revealed a great amount of resorption, suggesting the replacement of bone graft with soft tissue. Histologic evaluation revealed no evidence of active bone formation. A mass of connective fibrous tissue was infiltrated with inflammatory cells. In between, the presence of trabecular bony structures with a distribution of empty lacunae was illustrative of graft remnants.

    Keywords: guided bone regeneration, alveolar ridge augmentation, Allograft, bone regeneration
  • Marzieh Alikhasi *, Abbas Monzavi, Hooman Ebrahimi, Maryam Pirmoradian, najafabadi, Ahmadreza Shamshiri, Rezvaneh Sadat Ghazanfari Hashemi
    Introduction
    The removal of ceramic veneers is a time-consuming procedure in a dentaloffice. Little research has been done in alternative removal techniques for ceramic veneers.The objective of this study was to evaluate the removal of feldspathic and lithium disilicatereinforced glass ceramic veneers by Er, Cr: YSGG and to measure debonding time and pulpaltemperature increase during veneer removal.
    Methods
    Fifty-seven bovine incisor teeth were prepared and divided into 3 groups. Ceramicspecimens with a thickness of 0.7mm, a width of 4mm and a length of 8 mm were fabricatedfrom feldspathic ceramic, lithium disilicate reinforced glass ceramic HT (high translucency) andlithium disilicate reinforced glass ceramic MO (medium opacity) (19 for each group). Specimenswere cemented on the labial surface of incisors using resin cement. The Er, Cr: YSGG laserwas applied to each specimen at 2.5 W and 25 Hz. Debonding time was measured for eachspecimen, and the intrapulpal temperature was detected in 3 specimens for each group. Datawere analyzed via one-way analysis of variance (ANOVA) at significance level of 0.05 (α = 0.05).
    Results
    Mean debonding time was 103.68 (26.76), 106.58 (47.22) and 103.84 (32.90) secondsfor feldspathic, lithium disilicate MO, and lithium disilicate HT respectively. There was nosignificant statistical difference among the groups (P value = 0.96). The intrapulpal temperatureincrease was less than 1°C in all groups.
    Conclusion
    Er, Cr: YSGG can successfully be used to efficiently debond feldspathic and lithiumdisilicate reinforced glass ceramic veneers. There was no significant difference for debondingtime among these ceramic materials. During ceramic laminate veneer removal by laserirradiation, no irritating temperature rise was detected.
    Keywords: Porcelain Laminate Veneer, Er, Cr: YSGG Laser, Debonding
  • مرضیه علی خاصی، نرگس عامری*، حکیمه سیادت، احمدرضا شمشیری، محمدرضا نجاتی
    زمینه و هدف
    خطاهایی که در هر یک از مراحل ساخت فریم ورک زیرکونیایی ایجاد می شود، ممکن است باعث از بین رفتن تطابق رستوریشن نهایی گردد. هدف از این مطالعه بررسی تغییرات ابعادی فریم ورک های زیرکونیایی بریج سه واحدی متکی بر ایمپلنت، در طی مراحل مختلف ساخت توسط سیستمCAD/CAM ، Zirkonzahn بود.
    روش بررسی
    مدل اصلی با مانت کردن دو اباتمنت ایمپلنتی به عنوان پایه های بریج سه واحدی (کانین تا پره مولر دوم ماگزیلا) ساخته شد. توسط اسکنر سیستمZirkonzahn ، مدل اصلی 12 بار اسکن شده و 12 فریم ورک در اندازه مدل اصلی تراشیده شد (نمونه های تراش) و 12 فریم ورک با احتساب میزان انقباض در ابعاد بزرگتر تراشیده و سپس سینتر شد تا به ابعاد مدل اصلی برسد (نمونه های سینتر). ابعاد مدل اصلی و فریم ورک های مرحله تراش و سینتر در مناطق مشخصی توسط دستگاه VMS (Video Measuring System) اندازه گیری شد. همچنین این ابعاد در داده های اسکن توسط نرم افزار CATIA
    اندازه گیری شد. اختلاف ابعاد در هر یک از مراحل ساخت نسبت به مدل اصلی محاسبه شد. تاثیر دو فاکتور (مرحله ساخت و اندازه اباتمنت) بر میزان تغییرات ابعادی فریم ورک ها توسط Two-Way ANOVA ارزیابی شد. در صورت وجود Interaction بین فاکتورها، از Paired t test (اباتمنت) و Repeated measures ANOVA (مراحل) استفاده شد. حد معنی داری آماری 0/05 در نظر گرفته شد.
    یافته ها
    طبق نتایج به دست آمده از مطالعه حاضر، در تمام ابعاد، تغییرات در مرحله تراش بیشتر از دو مرحله دیگر بوده است. همچنین در تمام مراحل، تغییرات ارتفاع پره مولر نسبت به کانین بیشتر بود (0/001>P).
    نتیجه گیری
    با وجود محدودیت های این مطالعه به نظر می رسد، مراحل ساخت و نیز اندازه اباتمنت بر میزان تغییرات ابعادی فریم ورک های زیرکونیایی تاثیرگذار می باشند.
    کلید واژگان: زیرکونیا، تطابق داخلی، CAD-CAM
    Marzieh Alikhasi, Narges Ameri*, Hakimeh Siadat, Ahmad Reza Shamshiri, Mohammadreza Nejati
    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.
    Keywords: Zirconia, Internal adaptations, CAD-CAM
  • سودابه کولیوند، حکیمه سیادت، صفورا قدسی*، مرضیه علی خاصی
    زمینه و هدف
    با وجود گسترش روز افزون اسکنرهای داخل دهانی، تاثیر محل قرار گیری فینیش لاین نسبت به مارجین لثه در تطابق رستوریشن های ساخته شده روش دیجیتال همچنان مورد بحث است. هدف از این مطالعه بررسی تطابق کوپینگ های ساخته شده به روش دیجیتال در دو ختم تراش زیر و حد لثه در سطوح مختلف دندانی بود.
    روش بررسی
    30 دندان پرمولر تراش خورده جهت دریافت روکش متال- سرامیک وارد مطالعه شدند. 15 دندان ختم تراش بالای لثه و 15 دندان ختم تراش زیر لثه داشتند. اسکن دیجیتال توسط اسکنر داخل دهانی(Trios 3shape) از دندان تراش خورده انجام گرفت .فریم ورک های کبالت کروم به روش CAD/CAM ساخته و در دهان امتحان شد. پس از تنظیمات لازم گپ داخلی و مارجینال رپلیکای سیلیکونی با استفاده از استریومیکروسکوپ اندازه گیری شد. اطلاعات مربوط به گپ داخلی و مارجینال توسط روش Multivariate آنالیز شد (05/0P<).
    یافته ها
    میانگین گپ داخلی و مارجینال در گروه بالای لثه به ترتیب 1/52 و 27/56 میکرومتر و در گروه زیر لثه 72/49 و 98/62 میکرومتر محاسبه شد. موقعیت ختم تراش تاثیر معنی داری در نتایج به دست آمده نداشت (05/0P>).
    نتیجه گیری
    کوپینگ های کروم- کبالت ساخته شده به روش دیجیتال تطابق داخلی و مارجینال قابل قبولی نشان می دهند، هر چند محل ختم تراش در مقادیر گپ داخلی و مارجینال تاثیر معنی داری ندارد.
    کلید واژگان: تکنیک قالب گیری، تطابق مارجینال، طراحی کامپیوتری، تکنیک رپلیکا
    Sudabeh Kulivand, Hakimeh Siadat, Safura Ghodsi*, Marzieh Alikhasi
    Background and Aims
    Despite the increasing application of intra-oral scanners, the effect of finish line position on gingival margins adaptation is still discussed. The purpose of this clinical study was to evaluate the fitness of cobalt-chromium copings obtained from intraoral scanning in two depth of finish lines.
    Materials and Methods
    Thirty teeth prepared for single premolar metal-ceramic crowns were included. Fifteen teeth had supragingival and fifteen had sub-gingival finish lines. Digital impressions were made using an intraoral scanner (Trios-3shape). Computer-aided design and computer-aided manufacture (CAD/CAM) cobalt-chromium copings were fabricated from the scan files. The copings were evaluated intraorally and after adjustments, the internal and marginal discrepancy were measured using silicone replicas and a stereomicroscopy. Internal and marginal discrepancies were analyzed using the Multivariate test (P<0.05).
    Results
    The mean internal and marginal gap were 52.1 and 56.27μ, for supragingival group and 49.72 and 62.98μ for subgingival group, respectively. The evaluation of finish line position showed no significant effect on obtained results (P>0.05).
    Conclusion
    CAD/CAM chrome-cobalt copings fabricated by digital impressions provided acceptable marginal and internal precision. However, the finish line position had no significant effect on the internal and marginal adaptation.
    Keywords: Impression technique, Marginal adaptation, Computer-Aided design, Replica technique
  • Rezvaneh Ghazanfari, Nahal Azimi, Hanieh Nokhbatolfoghahaei*, Marzieh Alikhasi
    Introduction
    All-ceramic restorations are being widely used due to its various advantages. However, they have restricted durability and may have to be removed. The conventional procedure for removal is grinding the restoration with rotary instruments which are considered time-consuming and inconvenient. A newer advantageous method is the application of lasers for debonding ceramics from the tooth surface. The objective of this study is to provide a comprehensive literature review on laser-aided ceramic restorations debonding.
    Methods
    We searched PubMed and Google Scholar databases. Seven articles from 2011 to 2018 were identified. Studies were assessed for the efficacy of laser application and the amount of pulpal temperature rise.
    Results
    Studies selected were categorized according to variables including shear bond strength, debonding time and intrapulpal temperature. Oztoprak and Iseri investigated that erbium-doped yttrium, aluminum, and garnet (Er:YAG) laser application reduced shear bond strength of ceramic laminate veneers. The time of debonding took an average of 190 seconds in Rechmann’s study and 106 seconds in Morford’s study. One of the main issues while using the laser is thermal irritation of the pulp. A 5.5°C temperature increase may cause pulpal damage according to Zach and Cohen. Philips et al and Rechmann et al reported no intrapulpal harm due to temperature increase. Additionally, Phillips et al demonstrated that the laser setting affects both the debonding time and the temperature alterations and that a laser adjustment of 2.5 W/25 Hz would be the best safest group.
    Conclusion
    Removal of ceramic crowns and veneers from tooth surfaces can be successfully done by Er:YAG laser application in a less time-consuming procedure and without any harm to the underlying dentin. However, a temperature rise in the pulp may occur which could be overcome by adequate air water cooling.
    Keywords: Ceramic restorations, Er:YAG laser, Restoration removal, Debonding
  • Hakimeh Siadat, Hossain Najafi, Marzieh Alikhasi, Babak Falahi, Elaheh Beyabanaki*, Farid Zayeri
    Background
    The implant connection type might affect microleakage and screw loosening in two-piece implants. The aim of this study was to measure microleakage and screw loosening of two connections of Noble Biocare implant system before and after cyclic loading.
    Methods
    Twelve samples were categorized into two groups: external hexagon (Branemark) and internal hexagon connection (Noble Active) and two implants as controls. The abutments were tightened to a 35 Ncm torque. Initial torque loss (ITL) was measured five minutes after retightening the abutment, using a digital torque wrench. The samples were covered with putty material to the abutment‒implant junction. Customized metal crowns with 45° inclinations were placed on the abutments and cyclic loading was performed accordingly. Thereafter, the secondary torque loss (STL) was measured. Microleakage test was also performed. Data were analyzed with Mann-Whitney and Wilcoxon tests (α=0.05).
    Results
    There were no statistically significant differences between the two phases of gamma counting between and within two groups (P>0.05). However, STL after cyclic loading was less than ITL in both groups (P=0.042).
    Conclusion
    Connection type and cyclic loading had no significant effect on microleakage. Furthermore, the internal con-nection had less TL as compared to the external connection. In addition, the STLs were less than ITLs in both groups.
    Keywords: Dental implant?abutment connection, leakage, gamma rays, torque
  • Eaheh Beyabanaki, Marzieh Alikhasi
    This article describes the prosthetic treatment of a patient suffering from a hemimaxillary defect after surgical resection of an adenoid cystic carcinoma (ACC) in the palate. The patient had also received therapeutic irradiation. One year after radiotherapy, three implants were placed in the remaining maxillary bone without any bone augmentation. One of the implants failed during the osseointegration period. The implant replacing the failed one also failed during prosthetic procedures. The patient was unwilling to undergo another surgical episode, and the final prosthesis was completed on the two remaining implants.
    Keywords: Dental Implants, Maxillary Neoplasms, Implant-Supported Dental Prosthesis, Maxillofacial Prosthesis
  • Fatemeh Nematollahi, Marzieh Alikhasi, Elaheh Beyabanaki*
    Implants provide support, stability and retention for restorations used in fully and partially edentulous patients. This clinical report describes prosthetic treatment of a 30-year-old man suffering from a dentoalveolar deficiency due to an old gunshot trauma to the left side of the mandible. The patient was rehabilitated with implant-supported Toronto prosthesis following surgical placement of three implants with undesirable location and angulations due to lack of sufficient bone. This prosthetic option offers advantages of both screw-retained and cement-retained prostheses and provides acceptable aesthetic and functional results.
    Keywords: Dental cement, dental implant, implant-supported dental prosthesis
  • Fatemeh Amin, Yadollah Soleimani Shayesteh, Marzieh Alikhasi*
    Introduction

     The post-operative pain and swelling are frequently observed after different surgical procedures. Orofacial pain management is a challenging topic for the dental-medical profession. The main objective of this study was to compare the effects of two designed medical regimens in the context of post-operative management of pain and swelling following simple dental implant surgery. 

    Materials and Methods

     In this randomized and double-blinded controlled clinical trial, a total of 39 implants were placed in 31 patients by one clinician. Patients were divided into the test and control groups. Before surgery, each patient in the control group received 1gr of amoxicillin and 400 mgr of ibuprofen, and each one in test group received 1gr of amoxicillin, 400 mgr of ibuprofen and 0.5 mgr of dexamethasone. Antibiotic regimen, together with analgesics and anti-inflammatory treatment was provided after surgery for both groups. Pain was measured using visual analogue scale in days 1, 3 and 6 after surgery. Swelling was evaluated by a verbal scale in day 6. Also, the impact of following factors gender, age, duration of surgery, type and number of implant on pain and swelling was measured by the general linear model analysis. 

    Results

     The majority of patients in both study groups reported the pain to be mild, with peak intensity occurring at 24 hours after operation. No significant difference was observed across the groups for any given time. Also, there was no significant difference between two groups regarding their swelling profile. 

    Conclusion

     The experiments provide evidence that both of these methods are effective in pain and swelling reduction.

    Keywords: Pain, Swelling, Dexamethasone, Ibuprofen, Dental implants
  • مرضیه علی خاصی، امیر رضا هندی *
    زمینه و هدف
    از دست رفتن گیر پست یکی از دلایل اصلی شکست رستوریشن دندان های ترمیم شده با پست و کور می باشد. فاکتورهای متعددی من جمله نوع سمان می توانند بر گیر پست موثر باشند. با توجه به استاندارد در نظر گرفتن سمان زینک فسفات و مقایسه سایر سمان ها با آن، مطالعه حاضر با هدف مرور نظام مند مقالات جهت بررسی گیر پست های ریختگی سمان شده توسط زینک فسفات انجام گردید.
    روش بررسی
    این مرور نظام مند بر اساس راهنمای PRISMA (Transparent Reporting of Systematic Reviews and Meta-analyses) انجام شد. سوال این مطالعه این بود که گیر پست های ریختگی سمان شده توسط سمان زینک فسفات چقدر است. بر این اساس جستجوی الکترونیک مقالات برای یافتن مقالات مرتبط در پایگاه های اطلاعاتی PubMed و Medline و همچنین موتور جستجوی Google scholar تا سال 2016 در بین مقالات انگلیسی با کلیدواژه های مرتبط انجام شد. بعد از بررسی مقالات براساس معیارهای ورود و خروج، مقالات انتخاب و به صورت کیفی ارزیابی شدند.
    یافته ها
    حاصل جستجوی اینترنتی مقالات 1141 مطالعه بود که بعد از اعمال معیارهای ورود و خروج تعداد 6 مطالعه در این مرور نظام مند وارد شدند. پرکاربردترین جنس پست ریختگی از آلیاژ نیکل کروم بود. گیر پست های ریختگی توسط سمان زینک فسفات از 76/8 تا 2/34 کیلوگرم و از 91 تا 2/192 نیوتن گزارش شده بود.
    نتیجه گیری
    نتایج مطالعه مروری حاضر نشان داد که گیر پست های ریختگی سمان شده توسط زینک فسفات در شرایط کنترل شده در حد متوسط قرار دارد و فاکتورهای مختلفی شامل جنس و طول پست می توانند بر میزان گیر پست موثر باشند.
    کلید واژگان: پست و کور، گیر، زینک فسفات، سمان دندانی
    Marzieh Alikhasi, Amirreza Hendi *
    Background And Aims
    Loss of retention is one of the main reasons of failure in teeth restored with post and core. Several factors, including the type of cement can influence the retention of the posts. As zinc phosphate cement is considered as the standard for comparison this study performed to review articles evaluating the retention of cast posts cemented with zinc phosphate.
    Materials And Methods
    This systematic review was performed based on the PRISMA (Transparent Reporting of Systematic Reviews and Meta-analyses) guide. The question of this study was that how much is the amount of retention of cast posts cemented with zinc phosphate. Hence, a literature search was done in PubMed and Medline databases as well as Google scholar search engine using relevant keywords until 2016 limited to the English language. Articles were selected based on the inclusion and exclusion criteria, and were evaluated qualitatively.
    Resultes: Internet search resulted in 1141 articles. Following the application of inclusion and exclusion criteria, 6 studies were included in this systematic review. The most common post material was nickel-chromium alloy. Retention of casting posts cemented by zinc phosphate was from 8.76 to 34.2 Kg and from 91 to 192.2 N.
    Conclusion
    Our review showed that the retention of cast posts cemented with zinc phosphate in controlled condition is moderate and factors including post material and length could influence the retention of the post.
    Keywords: Post, core, Retention, Zinc phosphate, Dental cement
  • سمیه ذیقمی، مرضیه علی خاصی، مریم معماریان، معین حسینی شیرازی *
    زمینه و هدف
    جهت موفقیت کلینیکی پروتز های متکی بر ایمپلنت، تطابق اجزا متقابل و ثبات تورک اعمال شده به پیچ مجموعه ایمپلنت، تحت نیروهای اکلوزالی مکرر ضروری است. هدف از این مطالعه بررسی میزان کاهش تورک در اباتمنت های کست شونده با آلیاژ کروم کبالت پس از اعمال بارگذاری دوره ای بود.
    روش بررسی
    مرحله کستینگ توسط آلیاژ کبالت- کروم برای تعداد 10 عدد اباتمنت کست شونده با ابعاد و ارتفاع مشابه انجام شد. برای هر نمونه یک عدد ایمپلنت، به صورت عمود در آکریل مانت شده و پیچ های اباتمنت ها با تورک NCm 30 بر روی ایمپلنت مربوط به خود بسته شده و پس از 10 دقیقه باز شدند. میزان کاهش تورک در بازکردن اباتمنت ها برای هر نمونه ثبت شد. مجددا اباتمنت ها با تورک مشابه بر روی ایمپلنت مربوط به خود بسته شده و این بار نمونه ها تحت بارگذاری دوره ای قرار گرفتند. میزان کاهش تورک پس از بارگذاری برای هر نمونه اندازه گیری و ثبت شد. آنالیز آماری t-test برای اعداد به دست آمده از گروه ها انجام شد.
    یافته ها
    نتایج مطالعه نشان دادند که میزان درصد کاهش تورک قبل از بارگذاری دوره ای به طور معنی داری (001/0>P) کمتر از میزان درصد کاهش تورک پس از بارگذاری می باشد.
    نتیجه گیری
    در قطعات ایمپلنتی عدم تطابق اباتمنت های ریختگی با سطح متقابل، می تواند باعث کاهش درصد تورک اولیه قبل و بعد از بارگذاری شود. با این حال مناسب تر است که تفسیر نتایج حاصل از این مطالعه محدود به میزان شل شدن پیچ اباتمنت های مذکور باشد تا اینکه مستقیما به شکست های کلینیکی در استفاده از این نوع اباتمنت نسبت داده شوند.
    کلید واژگان: تورک، ایمپلنت دندانی، اباتمنت دندانی
    Somayeh Zeighami, Marzieh Alikhasi, Maryam Memarian, Moeen Hosseini Shirazi *
    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
    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.
    Keywords: Torque, Dental implants, Dental abutments
  • Marzieh Alikhasi, Hakimeh Siadat, Saeed Mehrab Hassani, Elaheh Tabatabaee*
    Statement of Problem

    Radiographs are commonly used to detect misfit of implant components, but various factors including implant connection and component opacity could affect this decision.

    Purpose

    The purpose of this study was to evaluate the diagnostic capability of senior students and experienced dentists on the adaptation of implant and impression coping in different vertical and horizontal angled radiographs.

    Materials and Methods

     The implant and the impression coping were attached to each other; once without any gap and once with a gap of 0.5 mm. Totally, 40 digital X-rays were taken with vertical inclinations of 0, 5, 10, 15, 20, 25, 30 degrees in positive and negative directions, and the rest were horizontally inclined with the same values. Forty senior students and twenty experienced dentists observed the radiographs. Their diagnoses were compared with the real status of components.

    Results

     No significant difference was observed between the performance of students and experts (P=0.74). Statistical T-test analysis revealed that the directions (inclinations toward the implants or the impression copings) does not result in any significant difference in diagnoses of students (P=0.29) and dentists (P= 0.15). Nevertheless, general linear model showed the radiograph angulations had a significant impact on the diagnoses of students (P=0.003) and dentists (P<.001). Youden factor revealed that there was not a consistent trend regarding sensitivity and specificity of vertically angled radiographs; however, sensitivity and in particular, specificity decreased as a result of horizontal angle inclination.

    Conclusion

     Increasing vertical angulations of the radiographs for diagnosing the adaptation of implant components is likely to reduce diagnostic capability of clinicians, even experienced ones. Specificity is more affected than sensitivity in both horizontally and vertically angled radiographs.

    Keywords: Dental implant, Impression coping, Gap, Radiography, Angulation, Experience
  • سمیه ذیقمی، حکیمه سیادت، مرضیه علی خاصی، زینب سعیدی *
    زمینه و هدف
    در این مطالعه تجربی آزمایشگاهی، دقت ابعادی و زاویه ای قالب های تهیه شده از ایمپلنت های زاویه دار با استفاده از تری تمام قوس در مقایسه با تری نیم قوس مورد ارزیابی قرار گرفت. با توجه به تعداد کم مطالعه در مورد تری های نیم قوس و همچنین شیوع بالای بی دندانی پارسیل کلاس یک کندی فک پایین، هدف از این مطالعه ارزیابی مقایسه ای تری های قالب گیری تمام قوس و نیم قوس بر دقت ابعادی و زاویه ای قالب های تهیه شده از ایمپلنت های زاویه دار بود.
    روش بررسی
    در این مطالعه از مدل اکریلی کلاس یک کندی فک پایین به عنوان مدل اصلی استفاده شد. چهار عدد ایمپلنت با طول 12 و قطر 3/4 میلی متر (Implantium، Dentium، Seuol، Korea) در ناحیه پره مولر و مولر اول با زاویه 30 درجه لینگوالی قرار داده شدند. قالب اولیه با آلژینات از مدل اصلی گرفته شد و از کست ریخته شده برای ساخت 20 تری اختصاصی باز به صورت تمام قوس و نیم قوس استفاده شد. در هر گروه 10 قالب با استفاده از ماده پلی ونیل سایلوکسان گرفته شد و کست ها با گچ تیپ IV ریخته شدند. از دستگاه (CMM) Coordinate Measuring Machine برای اندازه گیری مختصات ابعادی X)،Y،(Z و زاویه ای (q) ایمپلنت ها استفاده شد. داده ها با استفاده از نرم افزار SPSS22 و t-test با سطح معنی داری 05¤0 آنالیز شدند.
    یافته ها
    اختلاف بین گروه ها در جابجایی ابعادی در محورهای X ،Y،Z و به طور کلی در جابجایی خطی (r) با توجه به نوع تری قالب گیری معنی دار نبود، اما در جابجایی زاویه ای (∆q) اختلاف معنی داری بین گروه ها مشاهده شد (05/0P<).
    نتیجه گیری
    تری نیم قوس منجر به جا به جایی چرخشی کمتر در قالب گیری از ایمپلنت های زاویه دار می شود.
    کلید واژگان: قالب گیری، ایمپلنت های دندانی، ونیل پلی سایلوکسان
    Somayeh Zeighami, Hakimeh Siadat, Marzieh Alikhasi, Zeinab Saeidi *
    Background And Aims
    Taking impression from angulated implants has always been a great challenge in clinic. In this regard, studies on sectional trays are very few. The aim of this study was to evaluate and compare the dimensional and angular accuracy of impressions using full arch and sectional trays.
    Materials And Methods
    Four implants (4.3 × 12 mm) (Implantium, Dentium) were placed in the first premolar and molar regions of a Kennedy class I mandibular acrylic model with 30° lingual angulation. Twenty open special trays (Full arch & Sectional) were made on the primary cast. The impressions were taken using vinyl polysiloxane (VPS) and were poured with type IV dental stone. The coordinate measuring machine (CMM) was used to measure the dimensional (Z, Y, X) and angular (θ) coordinates of implants. The data were analyzed using and t-test and SPSS 22. Software.
    Results
    The type of tray had no significant effect on the dimensional accuracy in X, Y and Z axes (P>0.05) and total linear displacement (r); However, it significantly affected the angular accuracy (∆q) (P
    Conclusion
    Sectional tray yields less rotational displacement in impressions made of angulated implants.
    Keywords: Dental implants, Impression, Vinyl polysiloxane
  • حکیمه سیادت، امین جباری، محمد تقی باغانی، مرضیه علی خاصی *
    زمینه و هدف
    نشاندن دقیق ترانسفرهای قالبگیری، در ساخت پروتز های دقیق اهمیت به سزایی دارد. در برخی شرایط، لازم است ایمپلنت ها به صورت عمیق و زیر لثه ای قرار داده شوند. قرارگیری عمیق تر ایمپلنت می تواند سبب کاهش دید مستقیم و کاهش دقت اتصال ترانسفر قالب گیری و نهایتا کاهش دقت قالب گیری و عوارض متعدد ناشی از آن مانند ساخت پروتز بدون تطابق شود. هدف از انجام این مطالعه بررسی اثر عمق ایمپلنت بر صحت اتصال ترانسفر قالب گیری توسط دانشجویان می باشد.
    روش بررسی
    این مطالعه تجربی- آزمایشگاهی، بر روی 50 نفر از دانشجویان سال آخر دوره عمومی دندانپزشکی انجام شد. چهار ایمپلنت در عمق های مختلف (0 و 2 و 4 و 6 میلی متر) در یک مدل قرار گرفتند. بعد از آموزش نحوه سوار کردن ترانسفر قالب گیری و ایمپلنت بر روی هم، از دانشجویان خواسته شد که ترانسفر قالب گیری را بر روی هر چهار ایمپلنت ببندند. نمونه ها توسط یک متخصص پروتز مجرب به وسیله یک ذره بین با بزرگنمایی x4 بررسی شدند. داده ها توسط تست آماری Cochran آنالیز شدند (05/0P<).
    یافته ها
    میزان عملکرد صحیح در بستن ترانسفر قالب گیری، در ایمپلنت های با عمق زیر لثه ای 0 میلی متر100%، 2 میلی متر 62%، 4 میلی متر 58% و 6 میلی متر 20%، مشاهده شد. تفاوت آماری معنی داری بین تمام گروه های آماری مشاهده شد (001/0P<).
    نتیجه گیری
    نتایج نشان داد بین افزایش عمق ایمپلنت در زیر لثه و توانایی اتصال صحیح ترانسفر قالب گیری توسط دانشجویان، رابطه معکوس وجود داشت.
    کلید واژگان: ایمپلنت دندانی، عمق ایمپلنت، تکنیک قالب گیری دندانی
    Hakimeh Siadat, Amin Jabbari, Mohammad Taghi Baghani, Marzieh Alikhasi *
    Background And Aims
    The exact placement of impression copings in making accurate prosthesis is very important. In some cases, the implants need to be placed deeply subgingival, which could reduce the direct vision and ultimately reduce the precision of impression copings and subsequently, delivered prosthesis. This would be the cause of multiple complications such as delivery of ill-fitting prosthesis. The aim of this study was to evaluate the effect of the dental implant placement depth on the accuracy of impression coping connection by students.
    Materials And Methods
    This in-vitro and experimental study was conducted by 50 senior dental students. Four implants at different depths (0, 2, 4 and 6 mm) were placed in a model. After learning how to mount impression coping on implants, the students were asked to mount impression copings on all four implants. The samples were examined by an experienced prosthodontist using a magnifier with 4x magnification. Data were analyzed by statistical Cochran test (P
    Results
    The proper adapting rate of transfer copings, in subgingival implants with the depth of 0, 2, 4 and 6 mm were 100%, 62%, 58% and 20%, respectively. Statistically significant differences were observed between all groups (P
    Conclusion
    The results showed that there was an inverse relationship between the increasing depth of the implants in the gingiva and the dentist’s ability to connect the impression copings properly.
    Keywords: Dental impression technique, Dental implant, Dental Models
  • سیده نرگس عامری، حکیمه سیادت، احمدرضا شمشیری، مرضیه علی خاصی*
    زمینه و هدف
    تطابق مارژینال فریم ورک های ایمپلنتی، عامل مهمی در موفقیت طولانی مدت پروتزهای متکی بر ایمپلنت می باشد. هدف از این مطالعه مقایسه میزان گپ مارژینال مطلق فریم ورک های زیرکونیایی در بریج سه واحدی متکی بر ایمپلنت ساخته شده توسط دو سیستمComputer-aided design (CAD)/Computer-aided manufacturing (CAM)،AmannGirrbach و Zirkonzahn بود.
    روش بررسی
    مدل اصلی با مانت کردن دو اباتمنت ایمپلنتی به عنوان پایه های بریج سه واحدی (کانین تا پره مولر دوم ماگزیلا) ساخته شد. در هر سیستم 12 فریم ورک زیرکونیایی ساخته شد. میزان گپ مارژینال مطلق فریم ورک ها با استفاده از Video Measuring System در هر یک از اباتمنت ها اندازه گیری شد. تاثیر نوع سیستم CAD/CAM و سایز اباتمنت بر میزان گپ مارژینال مطلق به ترتیب توسط Independent t test و Paired t test ارزیابی شد و حد معنی داری آماری 05/0 درنظر گرفته شد.
    یافته ها
    میزان گپ مارژینال مطلق اباتمنت پره مولر، در فریم ورک های سیستم AmannGirrbach بیشتر از Zirkonzahn دیده شد (005/0P=). بین میزان گپ مارژینال اباتمنت پره مولر و کانین در هیچ یک از دو سیستم تفاوت آماری معنی داری مشاهده نشد (005/0P>).
    نتیجه گیری
    با وجود محدودیت های این مطالعه، به نظر می رسد میزان گپ مارژینال مطلق فریم ورک های زیرکونیایی به نوع سیستم CAD/CAM استفاده شده بستگی داشت، اما سایز اباتمنت تاثیری بر میزان گپ مارژینال مطلق نداشت.
    کلید واژگان: سیستم CAD، CAM، گپ مارژینال مطلق، زیرکونیا، فریم ورک، ایمپلنت، اباتمنت
    Seyedeh Narges Ameri, Hakimeh Siadat, Ahmad Reza Shamshiri, Marzieh Alikhasi*
    Background And Aims
    Marginal accuracy is a crucial factor influencing the clinical long-term reliability of implant-supported fixed dental prostheses (FDPs). The aim of this in vitro study was to evaluate the marginal fit of three-unit zirconia bridge frameworks fabricated using two different computer-aided design (CAD)/
    computer-aided manufacturing (CAM) systems.
    Materials And Methods
    The master model of 3-unit FDP was made of two implant abutments (AmannGirrbach and Zirkonzahn) from canine to second premolar. Twelve frameworks were manufactured using each fabricating system from semi-sintered zirconia blanks, which had to be sintered for final density after milling. After manufacturing, the absolute marginal discrepancy in each abutment were determined by means of Video Measurement System (VMS). The data were analyzed, using independent and paired t test (P=0.05).
    Results
    For the premolar abutment, the absolute marginal discrepancy of frameworks fabricated by AmannGirrbach system was significantly greater than those of the other system (P=0.005). There was no significant difference between the marginal discrepancy of canine and premolar abutments (P>0.05).
    Conclusion
    Within the limitations of this study, it could be concluded that the marginal fit of zirconia FDPs was significantly dependent on the CAD/CAM system used, but the abutment size was not an effective factor.
    Keywords: CAD, CAM system, Absolute marginal discrepancy, Zirconia, Framework, Implant, Abutment
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  • دکتر مرضیه علی خاصی
    دکتر مرضیه علی خاصی
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