جستجوی مقالات مرتبط با کلیدواژه « bulk fill composites » در نشریات گروه « پزشکی »

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.

Statement of the Problem: 

In an attempt to fasten and simplify the restoration process, a new class of composite resins, called the bulk fill composite resins have been introduced, which has been claimed to achieve a depth of cure (DOC) of 4 mm without affecting the properties of the material.

The Purpose of this study was to investigate the effect of different shades, thicknesses and viscosities on the DOC of bulk-fill composites.

Four bulk-fill composites [FiltekTMBulkfill Flowable (FBF), FiltekTM Bulkfill posterior (FBP), Tetric N-Flow bulkfill(TNF), Tetric N-Ceram bulkfill(TNC)] and a conventional composite, FiltekTM Z250XT Universal (FZ) were evaluated. samples (n=5) were made using two different shades( light and dark), thicknesses (2 and 4mm) and viscosities (flowable and sculptable). Microhardness was conducted on top and bottom surface using Vickers microhardness tester and DOC calculated as the bottom/top ratio. Statistical analysis was done using a mannwhitney test at p < 0.05.

DOC ranged between 52-95%. FBF composite exhibited the lowest overall hardness numbers. At 2-mm thickness, all the samples achieved an appropriate DOC. However, at 4-mm thickness, only the light shades for FBF and TNF samples achieved a DOC very close to 0.8. At 4-mm thickness, the light shades for FBF, TNF and FZ samples exhibited significantly higher DOC compared to dark shades. For 4-mm-thick samples, DOC of FB )dark and light shades (and DOC of TN (light shade( were different in the flowable type from the sculptable type.

Shade and viscosity influence DOC of bulk-fill composites at 4-mm depths. For bulk-fill composites, 20s light curing appears insufficient for 4mm bulk-fill placement.