Full text
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| Author(s): |
Bruna Marin Fronza
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba |
| Defense date: | 2014-02-26 |
| Examining board members: |
Marcelo Giannini;
Flavio Henrique Baggio Aguiar;
Carlos José Soares
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| Advisor: | Marcelo Giannini |
| Abstract | |
The aims of this study were: (1) to characterize the inorganic content; (2) investigate light transmission (LT) through different thicknesses increments; (3) assess biaxial flexural strength (BFS) and modulus (MO) according to depth of cure; (4) verify degree of conversion (DC) and microhardness (MH) and (5) correlate polymerization stress (PS) and gap formation (GF) in class I cavities of bulk-fill restorative materials, compared to a regular composite resin. Four bulk-fill composites were tested: Surefill SDR flow (SDR), Filtek Bulk Fill (FBF), Tetric EvoCeram Bulk Fill (TEC) and EverX Posterior (EXP). Herculite Classic (HER) was used as control. To morphological and composition characterization of inorganic content, a portion of each material was immersed in solvents to remove resin matrix and then analyzed by energy-dispersive X-ray and scanning electron microscopy. The LT was measured through different material thicknesses (1, 2, 3 and 4 mm) by a laboratory-grade spectral radiometer spectroradiometer (n=5). To BFS and MO tests, discs (0.5 mm thick) were fabricated using a set of eight molds, to simulate polymerization depth of 4 mm. DC obtained by Confocal Raman spectroscopy and Knoop MH were measured in 4 mm depth class I cavities, which were placed with the composites and it respective adhesives (n=5). PS was determined for each material by an extensometer attached to a universal testing machine (n=5). Filler particles of bulk-fill composites presented irregular, spherical or cylindrical shape, which size varied from 0.1 ?m to 1 mm. Regarding composition analysis, aluminum, barium and silicon were identified in all composites. All materials demonstrated lower LT with increased increment thickness. No differences were found in translucency among bulk-fill composites, only SDR had higher light transmission than HER. However, light attenuation did not influence BFS of bulk-fill composites, while HER presented decreased BFS at deeper layers. Nevertheless, HER still had the highest MO. DC was uniform among depths for SDR, FBF and HER applied incrementally. Conversely, TEC, EXP and HER bulk-filling presented a decrease in DC with increased depth. To MH test, lower results with increased depth were detected only for TEC, indeed there was no correlation between DC and MH analyzes. Regarding PS, EXP had the highest values, whilst TEC the lowest ones. Positive correlation was detected between PS and GF, which varied according to materials. Incremental filling technique reduced GF percentage to HER, and only SDR and TEC had comparable results to this conventional technique. Some of the bulk-fill composites presented similar or superior outcomes compared to control, which may be an option for traditional direct restorative procedures (AU) | |
| FAPESP's process: | 13/05247-4 - Evaluation of physicochemical properties of bulk-fill composite resins |
| Grantee: | Bruna Marin Fronza |
| Support Opportunities: | Scholarships in Brazil - Master |