Showing 7 results for Microleakage
Ar Danesh Kazemi , Ar Davari, H bidram - Gargabi ,
Volume 14, Issue 3 (10-2006)
Abstract
Introduction: In different investigations, the destructive effect of ultrasonic scalers on the margins of composites has been studied, but there are very few studies on the effects of ultrasonic scalers on the microleakage of poly-acid modified composite resin and resin modified glass ionomers. The main purpose of this study was to evaluate the marginal microleakage of class V preparations restored with resin modified glass ionomer and poly-acid modified composite resin before and after scaling with an ultrasonic scaler.
Methods: This in vitro study was performed on 160 premolar teeth. Standard class V cavities were prepared on the buccal surfaces of the selected teeth. Occlusal and cervical margins were placed entirely in enamel and cementum, respectively. Teeth were randomly divided to two groups of eighty, each. For one half of each group, (40 teeth) resin modified glass ionomer and for the other half, polyacid modified composite resin was used. Each one of the binary groups was subdivided to two groups. First subgroup was restored with Fuji II Lc (Fuji Japan) and Vitremer (3M USA ) and the second subgroup was restored with F2000 compomer (3M USA) and Compoglass(Vivadent Germany). For bonding to enamel, dentinte,cementum Singlebond (3M USA) and Adhese 2 (Vivadent Germany) were used and all of the restorations were done according to instructions of the manufacturers. In ten teeth of each group, ultrasonic scaling was done and in the other ten teeth, scaling was not done. After that, all of the teeth were thermocycled and immersed in fuschin. After cutting the microleakage was evaluated. The data was analyzed by Mann – Whitney, Kruskal – Wallis and Wilcoxon tests and significant border was 0.05 .
Results: The results showed that the degree of microleakage in enamel margins of poly –acid modified resin composites was lower than resin modified glass ionomers and in all groups and subgroups, the microleakage in enamel and cementum after scaling was significantly more than the groups without scaling.
Conclusion: Use of resin modified glass ionomers in class V restorations has no advantages over polyacid modified composite resins.
Aa Soleimani, Z Bahrololumi, M Kabudan, M Mousavi Nasab , A Abarghooyi,
Volume 20, Issue 4 (10-2012)
Abstract
Introduction: Contamination of etched enamel to saliva before placement of sealant prevents the appropriate bonding and results in microleakage. Using bondings is effective for decreasing the microleakage. This experimental study aimed to evaluate the effect of bonding agent on microleakage of a fissure sealant before or after contamination to saliva.
Methods: In this experimental study 40 sound premolar teeth were randomly divided into four groups. The prophylaxis was done and the teeth were etched with 37% phosphoric acid gel, then they were washed and dried. In the first group, Seal-Rite fissure sealant and Dentastic (Pulpdent, USA) without saliva contamination, and in the second group sealant with bonding agent after saliva contamination for 10s, were applied and cured for 40s. In the third group, fissure sealant without bonding agent or saliva contamination, and in the fourth group fissure sealant without bonding application was applied after contamination with saliva and then was cured. After thermocycling, the teeth were placed in 50% silver nitrate for 2 hours. The buccolingual sections were applied and microleakage evaluation was made by stereomicroscope at 4X magnifications and results were evaluated with mann-whiteny test.
Results: The fissure sealant group without bonding agent showed the most microleakage after contamination to saliva and use of sealant with bonding agent significantly showed decrease of microleakage.
Conclusion: Use of bonding agent under fissure sealant in saliva-contamination status is beneficial for decreasing microleakage.
Ar Daneshkazemi , Ar Davari, M Mousavinasab, M Hatamihajiagha, Ma Haddad,
Volume 21, Issue 3 (8-2013)
Abstract
Introduction: Characteristics of Dental materials may be examined under stimulated oral conditions like loadcycling and Thermocycling. The aim of this study was to evaluate the effect of loadcycling on microleakage of class V cavity preparations restored with composite and total etch adhesives.
Methods: One hundred class V preparations (5mm×3 mm and 2.5mm axial Depth) with incisal margin in enamel and gingival margin in dentin, were prepared in the anterior bovine teeth. The teeth were randomly divided into two groups which restored with single Bond (3M-USA) or excite (Ivaclar/viva dent/Lichtenstein). Each group was further divided into five subgroups. The numbers of used loadcycles involved respectively 0, 50k, 100k, 200k, 300k. [K=1000] Then, all the teeth were covered with sticky wax except 1mm around the samples and were immersed in 2% methylene blue for 24 hours. Then all the teeth were sectioned longitudinally and the scores of Dye penetration were registered under stereomicroscope. The study data were analyzed using kruskal Wallis and Mann Whitney and wilcoxon tests.
Results: All the dentin margins showed higher microleakage than enamel margin (P=0.0001). There was no significant difference between the microleakage of single bond and Excite(P>0/05). The effect of the number of loadcycles on the microleakage of the single bond and Excite in dentin and enamel margin was not significant.
Conclusion: Enamel margins showed less microleakage than dentin margins. This study did not show any increase in microleakage after increasing the number of loadcycles
Ar Davari, Ar Daneshkazemi, H Assarzadeh, M Karabi, F Mirhoseini,
Volume 22, Issue 3 (8-2014)
Abstract
Introduction: In spite of improvements in composite function, marginal microleakage in deep composite restoration is still considered as a challenge due to unstable bond between composite and dentin. Therefore, this study aimed to investigate effect of applying different materials on marginal microleakage in posterior composite restoration.
Methods: A standard distal box was prepared on 80 human premolar. The gingival floors were 1 millimeter under CEJ. The specimens were divided to four groups. In the first group, 1 millimeter amalgam was used as the first increment in proximal box on gingival floor, in the second group flow able composite, and in the third group, RMGI were used. Other cavities were filled by condensable composite. In the fourth group (control), all the cavities were filled only by condensable composite. The specimens, after 6 months of storage, were placed under cyclic load (10000 cycle- 80 N- 1 Hz), and then were immersed in 2% methylene blue for 6 hours. Afterwards, the specimens were sectioned in the middle of restoration. Extension of dye penetration at the cervical margin was examined under a stereo microscope at 25x magnification and the leakage was evaluated by Fuks degree. The study data were statistically analyzed using the Mann- Whitney U-test (p<0.05).
Results: Microleakage was observed in all the groups. The third group demonstrated the most leakage and the least was for the first group. No statistically significant difference was observed between the groups.
)p-value =0.689)
Conclusion: In cavities with gingival floor under CEJ, different filling methods have no effect on marginal sealing.
F Abolghasemzade , B Esmaeeli , S Khoshguyan ,
Volume 23, Issue 8 (11-2015)
Abstract
Introduction: The effect of final finishing and polishing time on the microleakage of composites restorations are not yet recognized. Therefore, this study aimed to evaluate the effect of final finishing and polishing time on microleakage of hybrid composite restorations.
Methods: In this in-vitro study, 40 molar teeth of class 5 cavity(2mm occlusogingival×3mm mesiodistal×1.5mm depth) were prepared at the buccal surface. The cavities were restored via Z250 composite and cured for 40 seconds by LED Valo. The cavities were randomly divided into 4 groups(n=10) according to the polishing time(immidiate, polishing 15 minutes, 24hours and one week after restoration). The teeth were subjected to 500 thermal cycles and submerged in 2% fuchsin to evaluate rate of microleakage. After monting, the specimens were sectioned in half, that both halves were examined under a stereomicroscope. Kruskal Wallis and Mann Whitney tests were applied in order to analyze the study data ( &alpha=0.05).
Results: Polishing time did not produce any effects on the microleakage in the dentine margin )Pvalue=0/56) and even enamel margin (Pvalue=0/12). The difference between microleakage rate of dentine margin and enamel margin was not demonstrated to be significant in regard with polishing immediately (Pvalue=0/26( and polishing after 15 minutes )Pvalue=0/53) , though polishing after 24 hours (Pvalue=0/03) and one week ( Pvalue=0/00) was reported to make a significant difference between the both margins. Moreover, the rate of microleakage was observed less in the enamel margin.
Conclusion: The study findings revealed that different polishing time does not have any effect on the microleakage rate of Z250 restorations in both dentine margin and enamel margin.
Alireza Daneshkazemi, Mahnaz Ersi,
Volume 28, Issue 6 (8-2020)
Abstract
Introduction: An important disadvantage of current dental resin composites is their polymerization shrinkage and production of microleakage. This shrinkage can cause tooth sensitivity, marginal discoloration, and secondary caries. The objective of this study was to review the effective factors on microleakage of methacrylate and silorane composites and compare them with each other.
This reviewed article was compiled and searched on library sources and Google scholar, Pubmed, ISI of science database, using the key words “Microleakage, Siloran-Based Composite, Methacrylate-Based Composite, Retentive Groove, Light Curing Technique,” from 1984 -2019.
Although it is not yet definitely clear, which methods of layering techniques (oblique, vertical, split) are more suitable, it seems that the layering technique has advantage over the bulkythat can effective in decreasing the shrinkage caused by polymerization and the resulting microlaekage. It can also be concluded that silorane base composites have less shrinkage, but some factors such as cavity type, cavity extent, cavity margin distance to CEJ, type of silorane base bonding system are also involves in their microleakage. It seems the presence of retention grooves in the cavities seems useful, because it increases the bonding area and mechanical retention as well as decreases the marginal shrinkage due to polymerization and the resulting microleakage.
Conclusion: Finally, it can be said that microleakage cannot be stopped completely, and more studies, especially clinical studies, should be conducted to show the effects of these cases clinically.
Mehdi Tabrizizadeh, Fatemeh Ayatollahi, Fatemeh Valizadeh,
Volume 31, Issue 7 (10-2023)
Abstract
Introduction: Microleakage is one of the most important factors in the failure of root canal treatment. Microhardness is one of the physical properties of bioceramics that can be affected by various environmental factors such as enviromental humidity. The aim of this study was to evaluation the effect of adding water to semi-setting cement on the microhardness and microleakage of CEM cement.
Methods: 50 single-rooted teeth were selected. Teeth were cut from the CEJ region and the apical 3 mm of the root were trimmed and dentinal blocks with 5 mm height were prepared Peeso reamer size 2 was used to prepare the canal. The teeth were divided into two groups of 23 cases and two groups of 2 positive and negative controls. In the first group, CEM-cement prepared according to the manufacturer's instructions was placed in the canal. In the second group, after adding water to the semi-setting CEM cement mixture, the canal was filled with this cement. The samples were placed in 1% methylene blue for 3 days and then cut. Microleakage was recorded under a stereomicroscope. The microhardness of the samples was measured with Vickers device after mounting in acrylic resin. Statistical analysis was performed using SPSS19 software and Mann-Whitney Kruskal-Wallis and one-way ANOVA tests.
Results: There was a statistically significant difference between the two groups in microleakage (P-Value <0.008) and microhardness (P-Value <0.001).
Conclusion: According to the results of the present study, adding water to the semi-setting CEM cement not only does have a very bad clinical effect, but also may even increase sealling ability.
