جستجوی مقالات مرتبط با کلیدواژه
amalgam
در نشریات گروه پزشکی-
BackgroundOral lichenoid lesions (OLL) could be premalignant lesions. Hence, it is critical to investigate the epidemiologic aspects of oral lichenoid lesions.MethodsThis cross-sectional study evaluated the prevalence of oral lichenoid reaction in patients attending the Department of Oral Medicine, School of Dentistry, during 2007-2018. All clinically and histopathologically documented files of oral lichen planus (OLP)- like lesions were evaluated, and oral lichenoid reactions were identified. The site of oral involvement, potential causes of OLL, and medications accompanied with OLL were all documented. The data were analyzed using SPSS version 18.ResultsOf the 191 patients with OLL, 137 (71.7%) were females, and 54 (28.3%) were males, with a mean age of 46.242 ± 13.77. In contrast, the control group consisted of 190 patients with OLP. The control group included 112 women (58.9%) and 78 (41.5%) men. The mean age of patients with OLP was 45.4 ± 11.16 years old, which matched the OLL group. Medications (48.2%) and amalgam restorations (52%) were the two most common causes of lichenoid reaction. While levothyroxine was used more frequently (17.8%) in patients with OLP, anti-hypertensive (30.4%) medications were used more predominantly in patients with OLL. In the present research, 8.23% of lichenoid lesions and 4.2% of OLP exhibited dysplastic change. The prevalence of OLL was 15.8% in patients who were referred to the Department of Oral Medicine, School of Dentistry. The prevalence of dysplasia was statistically higher in OLL patients (P < 0.0001). The odds ratio was 4.6, 95% CI: 2.06-10.28.ConclusionThis study showed that the prevalence of dysplasia was statistically higher in OLL patients.Keywords: Lichenoid Reaction, Precancerous Conditions, Amalgam
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Introduction
Mercury is a neurotoxic element that is released from dental amalgam restorations. Since circumstantial evidence exists that the pathology of multiple sclerosis (MS) disease might be in part caused or exacerbated by inorganic mercury, we conducted a systematic review and meta-analysis using a comprehensive search strategy.
MethodsData bases (PubMed, Google scholar, Cochrane, Embase, Scopus, Ovid, Proquest, and Web of Science) were searched systematically to find the relationship between dental amalgam and MS. Studies were screened according to a pre-defined protocol. The quality of the articles was evaluated by two individuals. The titles and abstracts of the articles were organized and duplicate articles were discovered with the help of Endnote X5 resource management software. Finally, 6 articles were included in the meta-analysis. Random effect model was chosen to conduct the meta-analysis.
ResultsPooled mean difference of restoration numbers between two groups was 0.58 (95% CI: 0.33-0.83, P value<0.001) with greater numbers in MS patients. The pooled OR was 1.02 (95% CI, 0.86-1021, P=0.81), which was slightly higher for those with amalgam so they were more likely to develop MS. This slight increase in risk was not statistically significant.
ConclusionAlthough those who underwent a large number of amalgam fillings were at higher risk for MS, the difference between the two groups of patients and controls was statistically insignificant. It seems that the number of amalgam fillings can be an influential factor in the possibility of developing MS.
Keywords: Amalgam, Dental amalgam, Multiple sclerosis -
Background
Approximately 50% of dental amalgam is elemental mercury by weight. Accumulating body of evidence now shows that not only static magnetic fields (SMF) but both ionizing and non-ionizing electromagnetic radiations can increase the rate of mercury release from dental amalgam fillings. Iranian scientists firstly addressed this issue in 2008 but more than 10 years later, it became viral worldwide.
ObjectiveThis review was aimed at evaluating available data on the magnitude of the effects of different physical stressors (excluding chewing and brushing) on the release of toxic mercury from dental amalgam fillings and microleakage.
Material and MethodsThe papers reviewed in this study were searched from PubMed, Google Scholar, and Scopus (up to 1 December 2019). The keywords were identified from our initial research matching them with those existing on the database of Medical Subject Headings (MeSH). The non-English papers and other types of articles were not included in this review.
ResultsOur review shows that exposure to static magnetic fields (SMF) such as those generated by MRI, electromagnetic fields (EMF) such as those produced by mobile phones; ionizing electromagnetic radiations such as X-rays and non- Ionizing electromagnetic radiation such as lasers and light cure devices can significantly increase the release of mercury from dental amalgam restorations and/or cause microleakage.
ConclusionThe results of this review show that a wide variety of physical stressors ranging from non-ionizing electromagnetic fields to ionizing radiations can significantly accelerate the release of mercury from amalgam and cause microleakage.
Keywords: Amalgam, Mercury, Magnetic Resonance Imaging, Microleakage, Radiation, Electromagnetic, Radiofrequency -
سابقه و هدف
پالپ کپ غیرمستقیم (IPC)، درمانی است که از حیات پالپ دندان محافظت می کند. هدف این مطالعه بررسی میزان موفقیت درمان پالپ کپ غیرمستقیم به عنوان درمانی محافظه کارانه در دندان های دارای پوسیدگی عمیق می باشد.
مواد و روش هادر این مطالعه مقطعی، از بین بیمارانی که در سال 1394 درمان IPC برای آن ها انجام شده بود، 100 بیمار به صورت تصادفی ساده انتخاب شدند. تست های حیاتی پالپ (گرما، سرما و EPT) و تست های پری اپیکال (دق، لمس و جویدن) برای دندان موردنظر و دندان های کنترل انجام شد. همچنین دندان از نظر رادیوگرافیک نیز موردبررسی قرار گرفت و نشانه های موفقیت و یا شکست درمان بررسی شد.
نتایجاز بین 100 بیماری که درمان IPC دریافت کرده بودند، 91 دندان بعد از گذشت 4 سال نشانه های موفقیت درمان را داشت و تنها در 9 دندان درمان با شکست مواجه شده بود. به عبارتی دیگر میزان موفقیت درمان 91 درصد و میزان شکست درمان 9 درصد می باشد.
نتیجه گیریبا توجه به نتایج این پژوهش، IPC درمان مناسبی برای دندان های دارای پوسیدگی عمیق در هر دو جنس و تمامی سنین می باشد که نوع ماده استفاده شده جهت پوشاندن غیرمستقیم پالپ و نوع ماده ترمیمی استفاده شده جهت ترمیم دندان در میزان موفقیت تاثیری نداشته، بلکه عوامل دیگری ازجمله دقت حین انجام درمان، حذف تمامی پوسیدگی های دیواره آگزیال، ترمیمی باسیل مناسب و محدودکردن باکتری ها در موفقیت بالای درمان موثر می باشد.
کلید واژگان: پالپ کپ غیرمستقیم، کلسیم هیدروکساید، ریزنشت، ترمیم، کامپوزیت، آمالگام، تست حیات پالپFeyz, Volume:25 Issue: 6, 2022, PP 1333 -1341BackgroundIndirect Pulp Cap (IPC) is a treatment that preserves pulp vitality. This study aimed to investigate the success rate of indirect pulp cap therapy as a conservative treatment for deep carious lesions in permanent teeth.
Materials and MethodsIn this cross-sectional study, among the patients for whom IPC treatment was performed in 2015, 100 patients were randomly selected. Vital pulp tests (thermal, cold and electrical test) and pre-apical tests (percussion, tactility and chewing) were performed for the target tooth and control teeth. The tooth was examined radiographically and the signs of success or failure of treatment were examined, also.
ResultsOf the 100 patients who received IPC, 91 had signs of a successful treatment after 4 years, and only 9 had failed. In other words, the success rate of the treatment was 91% and the failure rate of treatment was 9%.
ConclusionAccording to the results of this study, IPC is an appropriate treatment for teeth with deep caries in both sexes and all ages, the type of the material used to seal the pulp and the restorative material used for dental restoration does not affect the success rate. But the most important factors are to apply the indirect pulp treatment carefully, avoiding bacterial contamination, and to seal the teeth with a hermetic restoration.
Keywords: Indirect pulp cap, Calcium hydroxide, Microleakage, Dental restorative, Resin composite, Amalgam, Pulp vitality tests -
مقدمهآمالگام، یکی از رایج ترین مواد پر کننده ی عیوب دندانی می باشد که همچنان، به واسطه ی محتوی جیوه و خطرات ناشی از رهایش آن و مقاومت به خوردگی محدود در محیط بدن، استفاده ی کلینیکی آن مورد بحث محققین می باشد. در این مطالعه سعی شده است با مقایسه ی چهار نوع آمالگام تجاری موجود (در ایران)، خواص مکانیکی، ریزساختاری و مقاومت به خوردگی آنها مقایسه شود.مواد و روش هادر این مطالعه ی آزمایشگاهی، تعداد 20 نمونه آمالگام از چهار نوع شرکت تجاری (Cinalux: Owzan Company, Iran Honghai Tech. China, ARDENT Amalgam, Sweden, و SDI (GS-80), Australia) موجود تهیه شد و سپس در آمالگاماتور با جیوه مخلوط شدند. سپس از هر برند، یک نمونه ی سخت شده به قطر و ارتفاع 6 میلی متر، توسط میکروسکوپ الکترونی روبشی (SEM)، مورد ارزیابی ریزساختاری قرار گرفتند. همچنین توسط دستگاه آزمون فشار تک محوره، خواص مکانیکی 3 نمونه از هر برند آمالگام ها، مورد ارزیابی قرار گرفتند. مقاومت به خوردگی یک نمونه از هر برند، به روش پولاریزاسیون در محلول نمکی نیز مورد مطالعه قرار گرفت. برای مقایسه ی دقیق داده های کمی، از تحلیل آماری آنالیز واریانس یک طرفه (ANOVA) با استفاده از نرم افزار Graph Pad prism 6 استفاده شد. اختلافات در مقادیر p value < 0/05، به صورت معنی دار اعلام شدند.یافته هاهر چند هر چهار نوع آمالگام مورد بررسی، عاری از فاز مضر گاما 2 بوده اند، اما به خاطر اختلاف در مورفولوژی فازها، مقاومت به خوردگی متفاوتی در محلول نمکی از خود نشان دادند. همچنین خواص مکانیکی آمالگام ها نیز به واسطه ی اختلاف در مورفولوژی فازها، متفاوت بوده است و هر چهار مورد، رفتار ترد و استحکام بالای 300 مگاپاسکال از خود نشان داده اند. به طور کلی، آمالگام نوع 2 (Honghai Tech. China) دارای برترین خواص نسبت به سایرین بوده است.نتیجه گیریطبق نتایج به دست آمده، ریزساختار آمالگام پس از سخت شدن، تاثیر قابل توجهی بر استحکام و مقاومت به خوردگی آن داشت. همچنین همه ی آمالگام های مورد استفاده در این مطالعه، از فازهای یکسانی تشکیل شده بودند.کلید واژگان: آمالگام، خواص مکانیکی، ریزساختار، فازIntroductionAmalgam is one of the most commonly used dental restorative material; however, because of its mercury content, risks of mercury release and its low resistance to corrosion, its clinical use is still a matter of debate among researchers. In this research four different commercially available amalgam products in Iran were studied and their mechanical, microstructural and corrosion resistance were studied and compared.Materials and MethodsIn this study, four different samples of commercially available amalgam (Cinalux, Owzan Company, Iran; Honghai Tech., China; ARDENT Amalgam, Sweden; and SDI [GS-80], Australia) were prepared and mixed with mercury in an amalgamator. Then a hardened sample, measuring 6 mm in diameter and height, from each brand was evaluated by scanning electron microscopy (SEM) for ultrastructural characteristics. In addition, 3 samples from each brand undewent a compressive test in a one-axis compression test device. Resistance to corrosion of 3 samples from each brand was tested by polarization method in saline solution. To exactly compare the quantitative data, one-way ANOVA was performed using Graph Pad Prism 6 software program (α = 0.05).ResultsThe results showed that although none of the samples had Gama-2 harmful phase, because of differences in the morphology of phases, they exhibited differences in corrosion resistance in the saline solution. Furthermore, their mechanical properties were different due to differences in the morphology of phases and all of them had brittle behavior and their compression strength was >300 MPa.ConclusionAccording to the results, the microstructure of amalgam significantly affects its mechanical properties and corrosion resistance. In addition, all the samples evaluated in the present study formed identical phases.Keywords: Amalgam, Mechanical properties, Microstructure, Phase
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مقدمه
دندانپزشکان، به دلیل مواجهه شغلی با آمالگام، در معرض استنشاق بخار جیوه هستند که سلامتی آن ها را به مخاطره می اندازد. هدف از انجام این مطالعه تعیین تاثیر بخار جیوه بر غلظت جیوه ادرار دانشجویان و متخصصان دندانپزشکی یکی از دانشکده های دندانپزشکی ایران بود.
روش بررسیجامعه مورد مطالعه شامل 40 نفر از دانشجویان و 10 نفر اساتید دندانپزشکی بودند. نمونه ادرار در پایان وقت کاری جمع آوری و غلظت جیوه آن با روش طیف سنجی جذب اتمی بخار سرد اندازه گیری شد. پرسشنامه ای به منظور تعیین تاثیر برخی عوامل شخصی و محیطی بر میزان جیوه ادراری توسط افراد تکمیل شد. آنالیز اطلاعات با استفاده از نرم افزار spss انجام شد.
یافته هامیانگین جیوه ادرار دانشجویان دندانپزشکی μg/l 34/4 ± 18/15 و متخصصین ترمیمی μg/l 05/1 ± 11/4 بدست آمد. اختلاف معنی داری بین غلظت ادراری جیوه در دو گروه فوق وجود داشت (0/001>P). در اساتید بین جیوه ادراری و ساعت کاری در روز همبستگی منفی بدست آمد (r=-0/789 ،P=0/007). همچنین در این مطالعه بین جیوه ادراری با جنس، سن، نوع آمالگام مصرفی، مصرف سیگاری و تعداد ترمیم های آمالگامی از لحاظ آماری ارتباط معنی داری وجود داشت.
نتیجه گیریاگرچه سطح جیوه ادراری تمام نمونه ها از مقدار توصیه شده توسط ACGIH کمتر بود با این حال توصیه می شود به طور مرتب میزان جیوه محیط کار دندانپزشکان ارزیابی گردد.
کلید واژگان: جیوه ادرار، آمالگام، دندانپزشکیIntroductiondentists are exposed to mercury vapor due to occupational exposure to amalgam Which can endanger their health. the aim of this study was to measure the concentration of urinary mercury in dental students and the restorative specialists one of the dental schools in Iran in order to determine the effect of mercury vapor on them.
MethodsThe study population Including 40 dental students and 10 restoration specialists. Sample urine at the end of work time was collected, and the concentration of mercury in urine was measured by cold vapor atomic absorption spectrophotometry. A questionnaire was completed to determine the effects of some personal and environmental factors on the amount of urinary mercury. Data were analyzed by using SPSS software.
ResultsThe mean concentration of urinary mercury in dental students was 15.18±4.34μg/L and the restoration specialists were 4.11±1.05μg/l. In addition, there was a significant difference between the concentrations of urinary mercury in the two groups (P <0.001). At specialist professors There was a negative correlation between urinary mercury and working hours per day (r=-0.78, p=0.007). Also, in this study, there was a significant relationship between urine mercury and sex, age, type of amalgam consumed, consumption of smoking and the number of amalgam restorations.
ConclusionAlthough the level of urine mercury in all samples was lower The recommended amount of ACGIH .Finally, the study is recommended mercury level monitoring for regularly evaluation of the workplace.
Keywords: Urine mercury, amalgam, mercury vapor -
مقدمهآمالگام، از رایج ترین مواد پر کننده ی دندان به شمار می رود که همچنان استفاده ی کلینیکی از آن مورد بحث محققین می باشد. این آلیاژ به واسطه ی محتوی جیوه و خطرات ناشی از آن و مقاومت به خوردگی محدود در محیط بدن، مورد انتقاد پژوهشگران قرار دارد. لذا در مطالعه ی حاضر، کامپوزیت های آمالگام/نانوهیدروکسی آپاتیت و آمالگام/نانوبایوگلاس برای کاهش محدودیت های فعلی آمالگام، طراحی و ساخته شد و تاثیر نوع تقویت کننده بر خواص مکانیکی و خوردگی آمالگام دندانی بررسی گردید.مواد و روش هادر این مطالعه ی آزمایشگاهی و تحلیلی، کامپوزیت های آمالگام/نانو هیدروکسی آپاتیت و آمالگام/نانوبایوگلاس تهیه شد؛ به این روش که 2 درصد وزنی نانوبیوسرامیک، قبل از اضافه کردن جیوه، به مخلوط پودر فلزات تشکیل دهنده ی آمالگام افزوده شد و سپس در آمالگاماتور با جیوه مخلوط شدند و سپس در قالب فولادی توسط سنبه فشرده شدند. سپس نمونه های سخت شده، توسط میکروسکوپ الکترونی روبشی (SEM) مورد ارزیابی ریزساختاری قرار گرفتند. همچنین توسط دستگاه آزمون فشار یونیورسال، خواص مکانیکی کامپوزیت ها مورد ارزیابی قرار گرفتند. مقاومت به خوردگی کامپوزیت ها به روش پولاریزاسیون پتانسیودینامیک، مورد مطالعه قرار گرفت. برای مقایسه ی دقیق داده های کمی، از آنالیز واریانس یک طرفه با استفاده از نرم افزار GraphPad Prism 6 استفاده شد. اختلاف آماری، معنی دار اعلام گردید (p value < 0/05).یافته هادر حالی که با افزودن هر دو نانوبیوسرامیک هیدروکسی آپاتیت و بایوگلاس، مقاومت به خوردگی کامپوزیت افزایش می یابد، تاثیر هیدروکسی آپاتیت در افزایش مقاومت به خوردگی آمالگام در محلول نمکی، بیشتر بوده است. همچنین افزایش دو درصدی ذرات تقویت کننده ی هیدروکسی آپاتیت و بایوگلاس، سبب بهبود خواص مکانیکی کامپوزیت به ترتیب به مقدار 15 و 12 درصد شده است.نتیجه گیریبه نظر می رسد، کامپوزیت های پایه ی آمالگام توسعه داده شده، گزینه ی مناسبی برای اهداف پر کردن دندان های خلفی با اثرات سوء کمتر (خوردگی کمتر و استحکام بالاتر) باشد و نانو ذرات هیدروکسی آپاتیت، موثرتر از بایوگلاس عمل کرده اند.کلید واژگان: هیدروکسی آپاتیت، بایوگلاس، آمالگام، خواص مکانیکیIntroductionAmalgam is one of the most commonly used dental restorative materials, whose clinical use is still a matter of controversy among researchers. The alloy is criticized due to its mercury content and its dangers and limited resistance to corrosion in the body. In the present study amalgam/nano-hydroxyapatite and amalgam/nano-bioglass composites were produced to eliminate the currently existing limitations and evaluate the effect of the type of reinforcing agent on the mechanical properties and corrosion resistance of amalgam.Materials & MethodsIn this analytical in vitro study, amalgam/nano-hydroxyapatite and amalgam/nano-bioglass composites with 2 wt% of nano-bioceramic were produced. Nano-bioceramic was added to the amalgam powder before adding mercury, followed by mixing with mercury in an amalgamator and compression in a steel mold. The microstructure of hardened samples was evaluated by scanning electron microscopy (SEM). In addition, the mechanical properties of the composites were evaluated using a universal compression test device. Resistance to corrosion of composites was studied by potentiodynamic polarization method. To compare the quantitative data, one-way ANOVA was performed using Graph Pad Prism 6 software (α = 0.05).ResultsThe results showed that by increasing both bioceramics of hydroxyapatite and bioglass, corrosion resistance of composites increased, with hydroxyapatite exerting a greater impact on corrosion resistance of amalgam in the saline solution. In addition, incorporation of 2 wt% of bioglass and hydroxyapatite resulted in 12 and 15 percentages of improvement in the mechanical properties of the composites.ConclusionThe developed amalgam basic composites seemed to be good choices for restoration of posterior teeth, with less harmful effects (lower corrosion and higher strength), and hydroxyapatite nanoparticles were more effective than bioglass.Keywords: Amalgam, Bioglass, Hydroxyapatite, Mechanical properties
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BackgroundPrevious studies have shown that exposure to electromagnetic fields produced by magnetic resonance imaging or mobile phones can lead to increased microleakage of dental amalgam.ObjectiveThe aim of the present study was to investigate the effect of electromagnetic field of a commercial dental light cure device and a common GSM mobile phone on microleakage of amalgam restorations.Materials and MethodsIdentical class V cavities were prepared on the buccal surfaces of 60 non-carious extracted human teeth. The samples were randomly divided into 4 groups of 20 samples each. The samples in the first group were not exposed to electromagnetic fields, while the second and the third groups were exposed to electromagnetic fields produced by a commercial light cure device, or mobile phone radiation (60 min), respectively. The fourth group was exposed to electromagnetic radiations emitted by both mobile phone for 60 min and light cure device. Then, teeth samples were scored for microleakage according to a standard dye penetration protocol by examination under a stereomicroscope.ResultsThe mean score of microleakage in the fourth group (light cure + mobile phone) was significantly higher than that of the control group (P =0.030). Moreover, the scores of microleakage in this group were significantly higher than that of the second group (light cure only) (P= 0.043).ConclusionExposure of amalgam restorations to electromagnetic fields produced by both light cure devices and mobile phones can synergistically increase the microleakage of amalgam restorations.Keywords: Light Cure Device, Amalgam, Microleakage, Electromagnetic Radiation, Mobile Phones
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IntroductionSealing ability of a retrograde filling material is an important factor for a successful endodontic apicoectomy. The purpose of this in-vitro study was to compare the sealing ability of calcium enriched mixture (CEM) cement versus amalgam as root-end filling materials.MethodsA total of 36 canals of extracted maxillary central incisors were instrumented and obturated using lateral compaction technique. The apical 3 mm of each root was resected and root-end prepared to a depth of 3mm.The teeth were randomly divided into two experimental groups of 15 teeth according to tested materials (Amalgam, CEM cement) and two negative and positive control groups of 3 teeth. Root- end cavities were restored with amalgam (group 1) or CEM (group 2). Sealing ability was evaluated by dye penetration method using Pelikan ink, and a stereomicroscope at x10 magnifications and 0.01 mm accuracy. Data were analyzed by T-test and PResultsThe mean linear dye microleakage for CEM cement and amalgam retrofilled groups were 2.08 and 3.77 mm, respectively. There was a statistically significant difference between the two groups (p<0.0001).Conclusionunder the condition of this in vitro study, CEM cement provides a better seal than amalgam when used as a retrograde filling material.Keywords: Sealing ability, Amalgam, CEM, Retrofilled
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Different materials and techniques are used in dental wear restoration with the objective of increasing teeth resistance, and providing an aesthetic appearance. The aim of this study was to compare the fracture resistance of amalgam and posterior composite in abrasioned premolar and molar teeth. In this study, 60 carries and restoration- free human permanent mandibular premolar and molar teeth, freshly extracted because of orthodontic, periodontal and surgery reasons, were used. Cusps of teeth were removed with a horizontally cut, and were randomly divided into four groups of 15 teeth each. Groups 1 and 2 received class II restorations with posterior composite and amalgam, respectively in 15 premolar teeth. Groups 3 and 4 had class II restorations with posterior composite and amalgam, respectively in 15 molar teeth. After finishing and polishing, all samples were subjected to 1.000 times thermocycling with a dwell time of 30 s at 5 ± 2 oC, and 55 ± 2 oC. Then, teeth were mounted in acrylic resin to a depth of 2 mm apical to the cemento-enamel junction, and force was applied to all samples in a universal testing machine until fracture occurred. The results obtained after fracture were analyzed using the Shapiro-wilk and one-way ANOVA tests. According to these results, the difference between groups 1-2, 1-3, 1-4, 2-3 and 2-4 was statistically significant (PKeywords: Fracture resistance, amalgam, posterior composite
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مقدمهآمالگام، ماده ی ترمیمی ایمن و موثر در ترمیم های مستقیم به شمار می آید. در صورت وجود ترمیم های وسیع آمالگام و شکست قسمتی از آن، تعمیر قسمت شکسته شده با مواد ادهزیو، یک روش محافظه کارانه است. بنابراین هدف از این مطالعه، بررسی استحکام باند کامپوزیت به آمالگام با کاربرد عوامل باندینگ مختلف بود.مواد و روش هادر این مطالعه ی آزمایشگاهی، 52 سیلندر آکریلی تهیه و داخل آنها آمالگام با میزان نقره ی 43 درصد پک شد و پس از گذشت 24 ساعت در دمای اتاق، سطوح آمالگام با فرز فیشور الماسی ساییده و به مدت 10 دقیقه در حمام اولتراسونیک قرار داده شدند. سپس نمونه ها به چهار گروه 13 تایی تقسیم و در هر گروه از عوامل باندینگ مختلف به ترتیب زیر استفاده شد: گروه 1: آمالگام + الوی پرایمر + Total etch (سینگل باند)، گروه 2: آمالگام + الوی پرایمر + Self-etch (جی- باند)، گروه 3: آمالگام + جی- باند و گروه 4: آمالگام + سینگل باند. کامپوزیت رزین به نمونه های آمالگام آماده شده با استفاده از مولد پلاستیکی ترانسلوسنت با دستگاه LED Turbo باند شد و سپس توسط دستگاه اینسترون، مورد آزمون استحکام باند برشی قرار گرفتند و در نهایت تجزیه و تحلیل داده ها از طریق آزمون آماری واریانس یک طرفه و آزمون تعقیبی LSD انجام شد.یافته هادر این مطالعه، بیشترین مقدار استحکام باند، مربوط به نمونه های باند شده با عامل باندینگ جی- باند (Mpa 06/9) و کمترین مقدار مربوط به نمونه های باند شده با عامل باندینگ سینگل باند (Mpa 14/5) بود و میانگین استحکام باند برشی در چهار گروه باهم تفاوت معنی داری داشت (001/0 > p value).نتیجه گیریاستفاده از عامل باندینگ Self-etch (جی- باند) در مقایسه با دیگر عوامل باندینگ مورد مطالعه، استحکام اتصال بهتری بین آمالگام و کامپوزیت ایجاد می کند.کلید واژگان: استحکام باند برشی، کامپوزیت رزین، آمالگامIntroductionAmalgam is a safe and effective restorative material in direct restorations. One of the conservative methods for the repair of a fractured amalgam restoration is the use of adhesive materials like composite resin. Therefore the aim of this study was to evaluate the bond strength of composite resin to amalgam with the use of different bonding agents.Materials and MethodsIn this in vitro study, 52 acrylic cylinders were made and amalgam containing 43% Ag was condensed into these cylinders. After keeping the amalgam samples at room temperature for 24 hours, the amalgam surfaces were abraded with a diamond bur and all the samples were immersed in an ultrasonic bath. Then the specimens were divided into 4 groups of 13 samples, and each group was treated with different boding agents as follows: group (1), amalgam alloy primer total etch (Single Bond); group (2), amalgam alloy primer self-etch (G Bond); group (3), amalgam G Bond; and group (4), amalgam Single Bond. Composite resin was bonded to prepared amalgam specimens with the use of translucent polyethylene mold and cured by LED Turbo, followed by testing with an Instron machine for shear bond strength. Finally data were analyzed with one-way ANOVA and LSD tests.ResultsIn this study, the highest bond strength value was recorded in specimens bonded with G Bond bonding agent (9.06 MPa) and the lowest value was recorded in specimens bonded with Single Bond bonding agent (5.14 MPa). The mean shear bond strength values in 4 groups exhibited statistically significant differences (p value = 0.001).ConclusionG Bond bonding agent yielded higher bond strength between amalgam and composite resin than other bonding agents used in this research.Keywords: Amalgam, Composite resin, Shear bond strength
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Background and AimConsidering the consequences of false positive (FP) and false negative (FN) diagnoses as well as the lack of information on the diagnostic ability of photostimulable phosphor plate (PSP) and complementary metal oxide semiconductor (CMOS) sensors in the detection of secondary caries, this study aimed to compare the diagnostic ability of these two sensors in the detection of secondary caries adjacent to amalgam restorations.Materials and MethodsThis diagnostic study was performed on 40 intact permanent premolars. Class II cavities were prepared and restored with amalgam. Periapical radiography was performed by using PSP and CMOS sensors via parallel technique. A 0.5-mm round bur was used to create another cavity under amalgam restorations. To simulate secondary gingival caries at the cementoenamel junction (CEJ), the samples were placed inside 0.1M lactic acid solution and were incubated at 37°C for three weeks. The teeth were placed in gypsum blocks and were radiographed again by CMOS and PSP sensors. The presence of decay was determined by an oral and maxillofacial radiologist, and the results were recorded in datasheets and were statistically analyzed by the ratio test.ResultsThe sensitivity and specificity of PSP in caries detection were 52.5% and 77.5%, respectively. The sensitivity and specificity of CMOS in caries detection were 57.5% and 82.5%, respectively. Incorrect diagnoses (FP+FN) were equal to 35% for PSP and 30% for CMOS (P=0.89).ConclusionThe results indicated that PSP and CMOS sensors have similar abilities in the detection of secondary caries under amalgam restorations, while none of the two sensors has the adequate ability for a precise and thorough diagnosis of secondary caries.Keywords: Dental digital radiography, Dental caries, Diagnosis, Amalgam
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Statement of Problem: Previous studies have shown that exposure of dental amalgam fillings to MRI and mobile phones can increase microleakage of amalgam restorations.ObjectivesThe aim of this study was to evaluate the effects of exposure to radiofrequency radiation emitted from indoor Wi-Fi access devices on microleakage of amalgam restorations.Materials And MethodsStandard class V cavities were prepared on the buccal surfaces of 69 extracted human premolar teeth. The samples were divided into two exposure groups and one non-exposed control group of 23 teeth each. The specimens in the experimental groups were exposed to a radiofrequency (RF) radiation emitted from a commercial 2.4 GHz Wi Fi router. The distance between the Wi-Fi router and samples was 30 cm and the router was exchanging data with a laptop computer that was placed 20 m away from the router. Teeth samples in the first exposure group (group A) were exposed to RF for 3 days while the second exposure group (group B) was exposed for 6 days. Then the teeth were sectioned and scored for microleakage under a stereomicroscope.ResultsThe score of microleakage was significantly higher in the exposure group A compared to that of the control group. However, the score of microleakage was not significantly different between the exposure group B and control group. Furthermore, the scores of microleakage was significantly higher in the exposure group A than that of the exposure group B.ConclusionsExposure of patients with amalgam restorations to radiofrequency waves emitted from commercial Wi-Fi routers can lead to increased microleakage of amalgam restorations.Keywords: Wi-Fi, Amalgam, Microleakage, Dental Amalgam, Radiofrequency (RF), Microwave
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مقدمهبازسازی ترمیم شکسته، محافظه کارانه تر از تعویض ترمیم است. ونیر کردن ترمیم آمالگام با ماده رزینی اپک نیاز های زیبایی را برطرف می کند. یکی از فاکتورهای مهم در کیفیت آمالگام بازسازی شده، بررسی کیفیت باند اینترفاسیال بین سطوح آمالگام و کامپوزیت است که از دو طریق تست میکرولیکیج و تست استحکام باند ارزیابی می شود. هدف از مطالعه حاضر ارزیابی تاثیر نوع آمالگام و همچنین نوع باندینگ مصرفی بر استحکام باند برشی بین آمالگام و کامپوزیت می باشد.روشابتدا، 72 عدد سیلندر استوانه ایی به ابعاد33×20 میلیمتر آماده شد. سیلندر ها به دو دسته A و B تقسیم شدند. گروه A با آمالگام Tytin (Kerr،USA) و گروه B با آمالگام سینالوکس (شهید فقیهی، ایران) پر شد. روی سطح آمالگام نمونه توسط فرز الماسی استوانه ایی(تیزکاوان، ایران) خش انداخته شد. تمام گروه ها اچ شده و شسته شدند. در گروه 1A بعد از اچ و شستشو هیچ کار بعدی روی آمالگام صورت نگرفت. در گروه A2 روی سطح آمالگام از عامل باندینگ single bond (3M،USA) استفاده شد، در گروه A3 از عامل باندینگ Excite (Ivoclar،Italy) استفاده شد. در گروه B1 همانند A1، در گروه B2 همانند A2 و در گروه B3 همانند A3 عمل شد. در تمام گروه ها، کامپوزیت DenFil قرار داده شد. سپس نمونه ها در دستگاه Universal Testing تحت نیروهای برشی قرار گرفته و سپس توسط استریومیکروسکوپ (Olympus، Germany) با بزرگنمایی 75 مورد بررسی قرار گرفتند. نتایج به دست آمده توسط تست آماری Tukey HSD مورد آنالیز قرار گرفت. در تست مذکور با توجه به ضریب اطمینان 95%، 05/0P< نشان دهنده تفاوت معنی دار بین گروه ها بود.یافته هابین گروه هایی که با آمالگام Tytin پر شده بودند، تنها در گروه A3، میزان استحکام باند به طور معنی داری بیشتر از گروه A1 بود (001/0P=). بین گروه هایی که با آمالگام سینالوکس پر شده بودند، میزان استحکام باند در گروه B3 به طور معنی داری بیشتر از دو گروه B1 و B2 بود(P=0.001، P=0.03 به ترتیب). استحکام باند به صورت معنی داری در A1 نسبت به B1، A2 نسبت به B2 و A3 نسبت به B3 بیشتر بود(001/0P=).نتیجه گیریبر اساس نتایج این مطالعه، نوع آمالگام همچنین نوع باندینگ مصرفی بر استحکام باند برشی بین آمالگام و کامپوزیت موثر می باشد. آمالگام Tytin استحکام باند بیشتری را نسبت به آمالگام سینالوکس ایجاد می کند. باندینگ Excite استحکام باند بیشتری نسبت به Single Bond دارد.کلید واژگان: استحکام باند برش، آمالگام، کامپوزیتBackground and AimsRepair of defective restoration is more conservative than replacing it. Veneering the amalgam restorations with opaque resin materials can satisfy the esthetic demands. Evaluation of interfacial bond quality between amalgam and composite surface is one of the important factors in assessing the quality of repaired amalgam which can be achieved by micro leakage test and bond strength test. The aim of this study was to assess the effect of introduced amalgam and also the bonding agent on shear bond strength of amalgam and composite interface.MethodsFirst¡ 72 acrylic models (20*33 mm) were provided and categorized into two groups of A and B. we used Tytin (kerr¡USA) amalgam in group A and Cinalux (Shahid faghihi¡ Tehran) amalgam in group B. Amalgam surface was scratched by using a diamond bur. All the groups were etched and rinsed. In A1 group¡ nothing was done after etching and rinsing. In A2 group¡ single bond and in A3 group Excite was used. B1¡ B2 and B3 groups were respectively prepared like A1¡ A2 and A3 groups. DenFil composite was used in all groups. Shear bond strength was assessed by using Universal testing machine. All the specimens were seen under stereo microscope (Olympus¡ Germany) with 75% magnification. Tukey HSD test was used for statistical analysis.ResultsIn the groups which were filled with Tytin¡ A3 group had significantly higher bond strength than A1 group (P=0.001). In groups which were filled with Sinalux¡ B3 group had significantly higher bond strength than B1 and B2 groups (P=0.001 and 0.03 respectively). Bond strength was significantly higher in A1 compare to B1¡ A2 compare to B2¡ and A3 compared to B3 (P=0.001).ConclusionAccording to the obtained results¡ the type of introduced amalgam and also the bonding agent can affect shear bond strength of amalgam and composite interface. Tytin amalgam compared to Cinalux amalgam can create more shear bond strength. Also¡ excite bonding causes higher bond strength compared to single bond.Keywords: Shear Bond Strength, Amalgam, Composite
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BackgroundAlthough it is one of the most toxic nonradioactive elements, mercury is widely used in dental amalgam. Mercury is a toxic element which can damage various organs such as central nervous system, renal, respiratory and hematologic systems. The adverse health impacts associated to exposure to some common sources of electromagnetic fields including laptop computers, mobile phones, MRI and mobile phone jammers have been evaluated by our laboratory in our previous investigations. In this study, we aimed to evaluate the effect of X ray exposure on microleakage of amalgam restoration.Materials And MethodsStandardized class V cavities were prepared on the buccal surfaces of 46 non-carious freshly extracted human premolars. The teeth were randomly divided into experimental and control groups. Experimental group were exposed to X-ray using an intraoral radiography machine at 60 kVp, 0.1 s, 7 mA with 2.5 mm Al total filtration. The absorbed dose was 245.0 ± 0.5 µGy. All specimens were placed in 2 % basic fuchsin solution for 24 hours. Then the specimens were sectioned and microleakage was assessed according to dye penetration using a stereomicroscope. Statistical analysis was performed with the Mann-Whitney U-test.ResultsMicroleakage was significantly higher in the X-ray exposed teeth compared to those of the non-irradiated samples.ConclusionThe results of the present study suggest that X-ray exposure increased microleakage of amalgam restorationsKeywords: X-ray, radiography, radiation, amalgam, microleakage, mercury
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Background And AimIt is important to evaluate the effect of the type of filling material on deformation and strength of tooth after filling and also the effect of filling depth on quality of restoration of a decayed tooth.
Material andMethodsThe Orthopantomogram (OPG) of the first and second molars of a 28-year-old man was made and the teeth were 3D modeled. The stress-deformation analysis was then performed on the models in the three states of normal tooth, tooth filled with amalgam and tooth filled with composite using finite element method under a distributed load of 400N equivalent to chewing force. Two values (1/2 and 1/3 of the tooth height) were considered for filling depth in the analyses.ResultsThe results showed that the normal first molar was exposed to a 7.2% greater risk of dental injuries compared to the normal second molar and also a greater stress is created in it when it is filled with composite. The first molar filled with a composite material is 13.7% weaker than the normal tooth while it is almost as strong as a normal tooth when it is filled with amalgam. The effect of the type of filling material on the strength and deformation of the second molar was trivial.ConclusionAmalgam is a more proper dental filling material for the first molar although a 16.7% change in drilling depth is needed for tooth preparation. Dental filling material and filling depth have a small effect on the strength and deformation of filled second molars.Keywords: Amalgam, composite, tooth strength, filling depth, tooth deformation -
BackgroundAssure Universal Bonding Resin is capable of providing a strong bond between orthodontic attachments and amalgam surfaces.ObjectivesThis study sought to assess the shear bond strength of orthodontic attachments to amalgam surfaces using Assure Universal Bonding Resin after different surface treatments.MethodsThis in-vitro experimental study was conducted on 120 amalgam samples in eight groups of surface roughening with diamond bur, sandblasting with aluminum oxide particles, Er, Cr: YSGG laser irradiation and polishing-only. Molar buccal tubes were bonded to amalgam surfaces using Assure primer and Transbond Plus light-cure composite. Half the samples were immediately subjected to shear bond strength testing while the remaining half were incubated at 37°C for one week, thermocycled (1000 cycles) and were then subjected to shear bond strength test. One-way ANOVA was applied to compare the bond strength of the groups and Tukeys test was used for pairwise comparisons. The adhesive remnant index (ARI; 4 point-scale) was also determined in the groups and the results were analyzed using the Kruskal-Wallis test.ResultsSignificant differences were noted in shear bond strength of attachments following the application of Assure among different surface treatment modalities (PConclusionsSandblasting and irradiation of Er, Cr: YSGG laser provided sufficiently high bond strength between amalgam and attachments following the application of Assure. Diamond bur and polishing did not provide adequately high bond strength.Keywords: Assure Universal Bonding Resin, Shear Bond Strength, Er, Cr: YSGG Laser, Sandblasting, Amalgam
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Background And AimA periapical endodontic surgery is an alternative treatment when teeth are not responding to conventional treatment and endodontic re-treatment.
CASE REPORT: The following case report presents a clinical case of maxillary right and left central incisors with unsatisfying endodontic surgery and severe sensitivity in the buccal mucous membrane. Radiographic examination revealed several fragments of amalgam as root-end filling material, surrounded by a periapical radiolucent area. The chosen treatment plan was to perform endodontic retreatment. Symptoms persisted in spite of the gutta-percha removal and calcium hydroxide intracanal medication. Hence, periradicular re-surgery was performed. However, deep tissue penetrated amalgam particles were difficult to explore and could not be removed completely. The root-end filling was done with mineral trioxide aggregate (MTA), and the lesion was subjected to histologic analyses. The treatment was successful due to the absence of painful symptoms and due to periapical bone repair after 75 months follow-up.ConclusionMTA can be used successfully in the situations with failed previous periradicular surgery with amalgam.Keywords: Amalgam, Apicectomy, Mineral Trioxide Aggregate, Periapical Re, surgery, Root End Filling ýMaterial -
BackgroundThis study aimed to investigate dentists supply and practice patterns following the implementation of the global budget system in Taiwan.Materials And MethodsData of reimbursement claims, municipal socioeconomic status and dental manpower were collected from the National Health Insurance administration, the Ministry of Internal Affair, and the Ministry of Health and Welfare, respectively. A multivariate linear regression method was used for data analysis.ResultsA municipality that reported a higher percentage of tertiary educated population (t = 3.718, PConclusionThis study has demonstrated a stabilizing effect of the global budget system on dynamics of dental manpower in Taiwan. A relationship between HHI and dentists move‑out rate has been found. The relationship between municipal socioeconomic status and the density of dentists has also been confirmed. In addition, reduced utilization of amalgam restorations was accompanied by increased utilization of tooth‑colored material restorations. Further investigations are indicated.Keywords: Amalgam, composite resins, dentist, global, budget, health insurance, Herfindahl, Hirschman Index
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BackgroundPrevious studies have reported an increase in the mercury release from dental amalgam restorations, following exposure to electromagnetic fields generated by sources such as mobile phones and magnetic resonance imaging (MRI). It has also been shown that MRI increases microleakage of amalgam restorations. In this study, Helmholtz coils are used for generating pulsed electromagnetic fields (PEMF)..ObjectivesThe purpose of this study was to evaluate the effect of PEMFs on microleakage of amalgam restorations, using a pair of Helmholtz coils..
Patients andMethodsStandardized class V cavities were prepared on the facial surfaces of 46 non-carious extracted human premolars. Then, the samples were randomly divided into experimental and control groups, each containing 23 teeth. The experimental group was exposed to the uniform magnetic fields generated by a pair helmholtz coils. The magnetic field strength at the central point of the two coils was 0.1 mT. All specimens were placed in 2% basic fuchsin solution. Then the teeth were sectioned, examined under a stereomicroscope, and scored for microleakage according to the degree of dye penetration..ResultsThere was no significant difference between the two groups regarding the microleakage score..ConclusionsThe results of the present study suggest that PEMF exposure does not have adverse effects on microleakage of amalgam restorations..Keywords: Pulsed Electromagnetic Fields, Amalgam, Microleakage, Helmholtz Coils
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