جستجوی مقالات مرتبط با کلیدواژه « microleakage » در نشریات گروه « پزشکی »

Apical surgery aims to eradicate the apical part of the root and the lesion to enhance the healing. The sealing ability of retrograde filling material is an essential factor affecting the success rate of the surgery. Mineral trioxide aggregate (MTA) is thegold standard of retrograde filling materials, with approved sealing capability and biocompatibility. Newly introduced root repair material with an approved antibacterial effect similar to MTA is Nano-fast cement (NFC) which should be investigated for its sealing ability. This study aimed to evaluate the sealing ability of NFC vs. MTA.

Root apices of 48 single-rooted teeth were resected at 90 degrees and were prepared at 3 mm depth. The teeth were randomly divided into 2 experimental groups (n=21), negative control group (n=3), and positive control group (n= 3). MTA and NFC plugs were condensed as retrograde filling material. The samples were evaluated by a modified fluid filtration device for 1 hour. The measurement was conducted at 24 h, 1, and 3 months. Data were analyzed by Friedman Test and Kruskal-Wallis test.

According to the results, NFC at 3-months interval showedthe least microleakage, and MTA had the highest at the baseline. However, the results between the two groups were not statistically significant in all intervals. NFC reached the ideal sealing ability within 1 month, which was reached for MTA after 3 months.

The results of this in vitrostudy showed that the microleakage value of NFC is comparable to MTA.In light of current findings, NFC shows characteristics of a suitable calcium silicate-based cement. Further clinical researches are needed to introduce the NFC as retrograde apical plug or for other endodontic applications.

Although oxidative mouthwashes have many antimicrobial benefits, it has been suggested that residual oxygen interferes with composite resin adhesion to dental structures. This study aimed to evaluate the effect of an oxidative mouthwash on the microleakage of composite restorations. Twenty-four extracted human third molars were randomly assigned into three groups: Group 1: a 0.05% sodium fluoride mouthwash, Group 2: an oxidative mouthwash, and Group 3: distilled water. The teeth were immersed in the corresponding solution for 10 minutes a day over 14 days. Class V cavities were prepared in the buccal and lingual surfaces of the teeth (n=15 per group) and restored with Filtek Z250 composite. The teeth were thermocycled between 5º C and 55º C for 1000 cycles, then immersed in 2% fuchsin solution for 24 hours, followed by sectioning in the bucco-lingual direction. The gingival and occlusal microleakage were inspected using a stereomicroscope. Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. The statistical significance level was considered at P 0.05. The highest and lowest average microleakage scores were observed at the gingival and occlusal margin of cavities immersed in the sodium fluoride mouthwash, respectively. No statistical differences were observed in microleakage among the three groups either at the occlusal or at the gingival margin (P>0.05). The Mann-Whitney U test showed a statistically greater microleakage at the cervical (1.05±1.1) compared to the occlusal (0.694±0.53) margins, irrespective of the treatment groups (P=0.033). Using an oxidative mouthwash does not affect the microleakage of composite restorations

Statement of the Problem:

 Sealants are placed to prevent carious lesion initiation and to arrest caries progression by providing a physical barrier that inhibits microorganisms and food particles from collecting in pit and fissures .The two most common materials used for sealing pits and fissures are resins and glass-ionomers. Ionoseal is a light curing GI composite cement.The aim of this study was to compare the microtensile bond strength and microleakage of Ionoseal with different surface pretreatment.

This in vitro ,an experimental study was conducted on 95 sound human premolar in 5 groups(in each group 5 teeth for microtensile test and 14 teeth for microleakage test).A :35% phosphoric acid + total etch adhesive + Ionoseal ,B :universal adhesive + Ionoseal ,C: 35% phosphoric acid + Ionoseal,D: Ionoseal, E: 35% phosphoric acid + Embrace fissure sealant. On the prepared buccal enamel of each tooth, a 5 mm block of the sealing material was created and underwent thermocycling .By serially cutting, specimens about1×1mm in cross section were obtained and loaded in tensile (0.5 mm/min) until failure occurred .For microleakage test,sealing material was placed into the prepared occlusal fissures and teeth were thermocycled and then immersed in methylene blue 5% .An incision was made buccolingually. The dye penetration rate was measured based on Williams and winter criteria under stereomicroscope.

Mean microtensile bond strength was significantly different between groups (P

The aim of this study was to compare the marginal microleakage between bulk-fill, preheated bulk-fill, and bulk-fill flowable composite resins above and below cemento-enamel junction (CEJ) using micro-computed tomography.

Sixty freshly extracted premolar teeth were prepared with a slot shaped cavities of a total of 120 Class II: 3 mm (bucco-lingual), 2 mm (mesio-distal) with mesial gingival margin located 1 mm coronal to CEJ, and distal gingival margin located 1 mm apical to the CEJ. The samples were randomly divided into two main groups according to the restorative material (Tetric EvoCeram and 3M Filtek), and each group was further sub-divided into three subgroups according to the consistency (bulk fill, preheated bulk fill, and bulk fill flowable). The specimens were thermocycled (500 cycles, 5–55 °C, 30 seconds dwell time) and immersed in a 50% ammonical silver nitrate for 24 hours. Microleakage was evaluated using micro-CT. Data analyzed via three-way ANOVA and random forest model (a machine learning algorithm).

There was no statistically significant three-way interaction between type of composite, location of gingival margin related to CEJ, and filling technique (P=0.103). However, the random forest model (a machine learning algorithm) showed type of composite is the most influential factor.

Within the limitations of this study, considering the importance of the type of composite, the teeth restored with preheated bulk fill composite showed decrease in microleakage in comparison with bulk fill flowable composite.

We aimed to evaluate the microleakage of composite resin and self-cure glass ionomer (GI) restorations in primary molars when the restorations were applied at the same day of silver diamine fluoride (SDF) treatment, and after 14 days.

Class V cavities made at the buccal surface of 64 deciduous molars. For the experimental group of 32 teeth treated with SDF (eight teeth filled with composite and eight teeth filled with GI after 1 day and 14 days), the remaining 32 teeth without application of SDF served as a control group. All samples were then thermocycled and immersed in 2% methylene before being molded in epoxy resin to facilitate cutting into two sections. The dye penetration was then measured using a stereomicroscope at 20× magnification.

Overall model test showed statistical significant difference among study groups (P < 0.001). Post hoc test showed significant difference for usage of silver diamine fluoride (P < 0.001) and non-significant differences for type of restoration (P=0.21) and time (P=0.43).

There was a significant reduction in microleakage following the usage of SDF before restoration over time.

Bleaching teeth is popular because the discoloration is a major people’s concern. This study aimed to compare the effect of three antioxidants on the microleakage of composite resin filling after bleaching teeth with 35% H2O2, thus minimizing the potential clinical toxicity of filling materials entering patients’ body.

Sixty-six extracted intact teeth were included in this study. After preparation of a ClV cavity on the buccal surface, the teeth were randomly divided into six groups (n=11, each). Except for group A (control), all others were bleached. Cavities in group A were filled with composite resin. In group B, the samples were immediately restored after bleaching while in group C, the filling was delayed for two weeks after bleaching. In groups D, E, and F, the cavities were treated with either sodium ascorbate, ascorbic acid, or vitamin C, and the filling restored. Teeth were sectioned and the microleakages examined microscopically, and the data were analyzed statistically.

Group A showed the least amount of microleakage. In Group B, there was a significant increase in the microleakage when the samples were filled immediately after bleaching. The microleakages among groups of C, D, E, and F were similar to those in group A.

The microleakage increased significantly after bleaching with 35% H2O2, while treating dental cavities with the antioxidants effectively reduced the microleakage. Thus, delayed filling is a useful approach to minimize the microleakage. The findings help reduce or prevent the clinical toxicity arising from the microleakage of filling materials.

Despite the incredible popularity of dental composites, their application is associated with several difficulties, one of the most important of which is the microleakage phenomenon. Incorporation of silver nanoparticles in composites exerts antibacterial effects; nonetheless, the impact of silver nanoparticles on microleakage has not yet been studied. This research conducted to assess the effect of silver nanoparticles application as a precursor on the microleakage of composite-filled clV cavities using two different approaches of universal bond application.

Sixty non-carious human molars were collected, and clV cavities were provided on the buccal surfaces. The samples were categorized to 4 groups (n=15 in each group) and were restored using four different methods. After placement in 2% basic fuchsin solution for 24 h, permeability was determined between the cavity wall and restorative material in the gingival and occlusal margins. Thereafter, one sample of each group was selected. After preparation, the specimens were analyzed using backscattered electron scanning electron microscopy. Finally, the cytotoxicity was assessed by the Methyl-thiazolyl-tetrazolium (MTT) assay.

In both gingival and occlusal margins, if the silver nanoparticles were used, microleakage significantly decreased (P≤0.001). The addition of silver nanoparticles had no adverse effect on human gingival fibroblasts (HGF) cell viability.

It seems that the use of silver nanoparticles in the total-etch method can improve phosphoric acid penetration into dentinal tubules, increases the depth of etching, and promotes the bond quality

In the field of pediatric dentistry, an urge to adopt a more comfortable, minimally invasive, and stressless technique for caries removal became a must. Coronavirus disease-2019 outbreak necessitates a paradigm change in the global health care protocols, requiring alternative, nonaerosol generating approaches. This study aimed to measure and compare the influence of two methods of caries removal, namely, Brix3000 and CeraBur, on the microleakage of glass hybrid restorative material.

Thirty human primary molar teeth with accessible occluso-gingival carious cavitation were randomly allocated into CeraBur and Brix3000 groups. After selective caries excavation, samples were restored with Equia Forte HT, thermocycled, dipped in thiazine dye, washed, and sectioned through the restoration center. Then microleakage was measured using a stereomicroscope (30× magnification) at both occlusal and gingival margins.

No statistically significant difference was found between the two methods of caries removal (CeraBur and Brix3000) at both occlusal (P = 1.000) and gingival margins (P = 0.612).

Brix3000 caries removing gel did not negatively affect the microleakage of Equia Forte HT compared to the CeraBur and hence can be used alternatively to the conventional drilling methods.

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.

This 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.

The 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.

Our 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.

The 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.

The aim of this study was to evaluate and compare the microleakage of three adhesives in class V composite restorations.

30 extracted third molars were divided into three groups based on the adhesive types. Two class V cavities were prepared on each tooth. An individual adhesive was used for bonding in each group and cavities were restored with resin composites. The specimens in each group were aged by thermal cycling and submerged in silver nitrate solution. Microleakage was assessed with a stereo microscope. Statistical analysis was performed to compare the extent of microleakage between the groups.

The microleakage of the universal adhesive G-Premio Bond was significantly lower than that of the other two bonding agents. No significant difference was found between G-Premio Bond and Iperbond Ultra (p> 0.99), although the 6th-generation adhesive Quickbond had the highest microleakage compared to the other two.

Microleakage was influenced by the type of adhesive. Lower levels of microleakage in the universal adhesives led to longevity and durability of the restoration.

Although dental composites have undergone a high level of development in recent years, there are still difficulties including microleakage. The incorporation of nanoparticles (NPs) in dental materials can produce antibacterial effects, but the effect of TiO2 NPs on microleakage has not yet been investigated. The present study aimed to determine the effect of TiO2 NPs incorporation in the universal single bond and pretreatment with them on microleakage of clV cavities using both total-etch and self-etch approaches.

Standard clV cavities were prepared on the buccal surfaces of the sixty non-carious human molar teeth. The restoration of samples was carried out with 6 different methods and randomly divided into six groups of ten subjects. Microleakage in both gingival and occlusal margins was determined after placement in 2% basic fuschin solution for 24h. Biocompatibility of a universal single bond was evaluated by MTT assay.

In both occlusal and gingival margins in all groups, the application of TiO2 NPs was better than no application. We observed the relatively low cytotoxic effect of TiO2 NPs incorporated in the universal adhesive on NIH-3T3 cell viability.

Regarding the limitations of the present investigation, using TiO2 NPs with both total-etch and self-etch approaches to universal single bond may lead to a decrease in the microleakage of resin composite restorations.

AH26, Master-Dent, and Endoseal mineral trioxide aggregate (MTA) are three different types of sealers. The purpose of this study was to assess and compare THE apical seal of the root canal-treated teeth with the above-mentioned sealers in the presence and absence of moisture using the fluid filtration method.

To this end, 54 freshly extracted single root canal human canines were selected for this study. The canals were prepared using rotary instruments, and then sodium hypochlorite was applied as an irrigation solution in this protocol. The specimens were randomly divided into three groups of 18. One group was obturated with the gutta-percha by the cold lateral compaction technique. Half of one of the aforementioned sealers belonged to the group of moistened teeth and the other half to the group of the dried teeth. Microleakage in all groups was assessed 3 months after the obturation of canals by the fluid filtration method. The data were analyzed using ANOVA and Tukey’s post hoc tests, and the level of significance was set at P<0.05.

The results showed that the minimum and maximum micro-leakage belonged to Masterdent dry (mean leakage = 1.7778 μL/ min/CmH20) and Endoseal-MTA dry (mean leakage = 3.5000 μL/min/CmH20), respectively. All three groups of sealers exhibited a significant difference in apical micro-leakage between dry and moist conditions (PMasterdent <0.001, PAH26=0.002, and PEndoseaL-MTA =0.007).

The findings of this experimental study demonstrated that Masterdent provided the least apical micro-leakage under dry conditions while Endoseal-MTA had the highest micro-leakage under these conditions. There was a significant difference between dry and moist conditions in all groups.

The aim of this study was to compare microleakage in Class V restorations using different composite resins and application techniques. In this study, 60 cavities were prepared on the buccal and lingual surfaces of samples, 3 mm length (mesio-distal), 3 mm height (cervico-occlusal) and 2 mm depth. Samples were randomly divided into 6 groups. In Group 1, Grandio (Voco GmbH, Cuxhaven, Germany) was used with bulk technique, in Group 2 by horizontal incremental technique and in Group 3 by oblique incremental technique. SonicFill (Kerr, CA, USA) in Group 4, Filtek Bulk Fill Posterior Restorative (3M ESPE, st. Paul, USA) in Group 5, and Estelite Bulk Fill flow (Tokuyama, Japan) in Group 6  were used with bulk technique. After thermal cycle, samples were incubated in 0.2% methylene blue solution for 24 hours. They were sectioned longitudinally from the middle of cavity (buccolingually). Microleakage was evaluated by stereomicroscope (Nikon SMZ25, Tokyo, Japan). Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis. Microleakage at the cervical margin was higher than the occlusal margin. There was no statistically significant difference between groups at the occlusal margin, but there was a significant difference between groups at the cervical margin (P₌0.02). In Groups using incremental techniques, less microleakage was observed. There was no statistically significant difference between groups using bulk technique. The use of incremental techniques in the restoration of cervical lesions may reduce microleakage.

The application of laser in dentistry for medical purposes such as caries removal, preparation of restorative cavities, and dental surface treatment for more effective bonding of restorative materials to the tooth has been significant. The present experimental study aimed to evaluate the effect of cavity preparation on microleakage by using erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) lasers, and to compare it with the effect of bur on microleakage in class V composite restorations.

In this experimental study, 20 intact human premolar teeth were randomly divided into 2 equal groups according to the cavity preparation technique: G1: laser cavity preparation (LCP) using a Er,Cr:YSGG laser (Bio Lase, USA), and G2: bur cavity preparation (BCP). Standard class V cavity was prepared on both lingual and buccal surfaces in two groups. The samples underwent thermocycling for 3000 times (5-55ºC) and were immersed in a methylene blue 2% solution for 24 hours. After buccolingual sectioning from the middle of the restoration, a stereomicroscope with 20 x magnification was used to measure the penetration rate of the dye and to determine the score for microleakage. Data were analyzed using SPSS (version 16) software and Mann-Whitney U test (α=5%).

According to the study results, the minimum and maximum microleakage values were observed in the occlusal and gingival margins, respectively, which were identically for both groups. Comparing two groups (BCP and LCP) revealed that there was no significant difference between them in terms of microleakage values at the occlusal and gingival margins (P>0.05).

It was concluded that cavity preparation using Er,cr:YSGG laser had microleakage values similar to those found with conventional cavity preparation (bur) method in class V composite restorations