Document Type : Original Article
Authors
- nafiseh elmamooz 1
- Mehdi rezaei 2
- ali Eskandarizade 3
- maryam bagheri nasab 4
- mehrnaz Karimi Afshar 5
1 Assistant Professor of Restorative Dentistry Department of Restorative Dentistry, School of Dentistry Kerman University of Medical Sciences
2 Resident of restorative dentistry ,Dept. of Restorative Dentistry, School of Dentistry, kerman University of Medical Sciences, kerman, Iran.
3 Professor,Dept. of Restorative Dentistry, School of Dentistry, kerman University of Medical Sciences, kerman, Iran.
4 Private Dentist, Kerman, Iran.
5 Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
Abstract
Background: Bulk fill composites are a new class of materials that introduced to speed up the clinical process of posterior restorations. The aim of this study was to compare the curing quality of bulk fill and conventional composites at different irradiation times and depths.
Methods: In this invitro study, 40 specimens from a bulk-fill composite, Tetric-N-ceram Bulk Fill (TNB) and a conventional composite, Tetric N-ceram (TN) were fabricated using a metal mold(6mm×4mm)(n=10). The composites were placed and cured in bulk for each composite. For each composite, the half of samples were cured for 20 second (s) using Light-Emitting Diode (LED) curing unit and irradiation time for other half was 40s. After 24 hours of storage in distilled water, the hardness of samples was measured using Micro hardness Tester at different depths (0.1,1,2,3,4 millimeter(mm)). Statistical analysis was done using Multivariate ANOVA and Independent T test (p˂0.05).
Results: Both composites presented a significant reduction on hardness value with increasing depth. Tetric-N-ceram Bulk Fill showed significantly higher hardness values at all depths in both irradiation time compared to conventional composite. TNB composite did not achieve depth of cure (DOC) of 4mm in both curing times. Irradiation time significantly affect hardness values in both composites.
Conclusion: Given that neither bulk fill nor conventional composite were cured at depths greater than 3mm, it is suggested that prolonged curing cycles be used to improve the depth of cure (DOC) of composites.
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