Journal article
Effects of different photo-polymerization protocols on resin-dentine mu TBS, mechanical properties and cross-link density of a nano-filled resin composite
Journal of dentistry, Vol.40(10), pp.802-809
10/01/2012
DOI: 10.1016/j.jdent.2012.05.014
PMID: 22687576
Abstract
Objectives: To evaluate the effects of four different light-curing protocols on the microtensile bond strength (mu TBS), ultimate tensile strength (UTS), Knoop micro-hardness (KH) and cross-link density (CLD) of a nano-filled resin composite.
Methods: Filtek Supreme XT (3M-ESPE) was used for the entire experiments following four light-curing approaches: ST, standard irradiance; HI, high irradiance; PD, pulse delay; SS, soft start. The specimens were submitted to different storage periods (24 h or 6 months), cut into match-sticks and subsequently submitted to mu TBS testing. Hourglass specimens were also prepared for UTS and KH. Cylindrical specimens were prepared for the CLD evaluation after absolute ethanol challenge. The results were statistically analyzed with a two-way ANOVA and Tukey's test (alpha = 0.05).
Results: For UTS and KH, continuous irradiance (PD and SS) induced statistically higher results (p < 0.05) both after 24 h and 6 months of water storage compared to ST and HI groups. However, a drop in UTS and KH was obtained after 6 months in all groups. The mu TBS was not affected by the different light-curing approaches and, no statistical differences (p > 0.05) were observed between 24 h and 6 months storage. The CLD evaluation showed a statistical drop in KH after 24 h of ethanol storage for PD and SS (step-curing protocols) compared to those attained in continuous mode (ST and HI).
Conclusion: The soft-start mode may improve the UTS and KH of nano-filled resin composites without compromising the resin-dentine mu TBS. However, both the step-curing protocols may reduce the cross-link density of the composite polymeric network.
Clinical significance: High irradiances photo-polymerization may be adequate for direct aesthetic restorations such as veneers and onlays. Meanwhile, the soft start protocol would seem more appropriate for the photo-polymerization of high c-factors class I and II restorations. (c) 2012 Elsevier Ltd. All rights reserved.
Details
- Title: Subtitle
- Effects of different photo-polymerization protocols on resin-dentine mu TBS, mechanical properties and cross-link density of a nano-filled resin composite
- Creators
- Victor Pinheiro Feitosa - Universidade Estadual de Campinas (UNICAMP)Ana Paula Piovezan Fugolin - Univ Estadual Campinas, UNICAMP, Piracicaba Dent Sch, Dept Restorat Dent,Div Dent Mat, Piracicaba, SP, BrazilAmerico Bortolazzo Correr - Universidade Estadual de Campinas (UNICAMP)Lourenco Correr-Sobrinho - Univ Estadual Campinas, UNICAMP, Piracicaba Dent Sch, Dept Restorat Dent,Div Dent Mat, Piracicaba, SP, BrazilSimonides Consani - Universidade Estadual de Campinas (UNICAMP)Timothy F. Watson - St Thomas' HospitalMario Alexandre Coelho Sinhoreti - Univ Estadual Campinas, UNICAMP, Piracicaba Dent Sch, Dept Restorat Dent,Div Dent Mat, Piracicaba, SP, BrazilSalvatore Sauro - Universidad de Granada
- Resource Type
- Journal article
- Publication Details
- Journal of dentistry, Vol.40(10), pp.802-809
- Publisher
- Elsevier
- DOI
- 10.1016/j.jdent.2012.05.014
- PMID
- 22687576
- ISSN
- 0300-5712
- eISSN
- 1879-176X
- Number of pages
- 8
- Grant note
- Programme Comprehensive Biomedical Research Centre II-3A-1109-10046 / National Institute for Health Research; National Institute for Health Research (NIHR) Wellcome trust; Wellcome Trust; European Commission Centre of Excellence in Medical Engineering
- Language
- English
- Date published
- 10/01/2012
- Academic Unit
- Operative Dentistry
- Record Identifier
- 9984655344802771
Metrics
3 Record Views