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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The Combination of CQ-amine and TPO Increases the Polymerization Shrinkage Stress and Does Not Improve the Depth of Cure of Bulk-fill Composites

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Author(s):
Rocha, M. G. [1] ; de Oliveira, D. C. R. S. [1] ; Sinhoreti, M. A. C. [1] ; Roulet, J. F. [2] ; Correr, A. B. [1]
Total Authors: 5
Affiliation:
[1] Univ Estadual Campinas, Piracicaba Dent Sch, Dept Restorat Dent, Piracicaba, SP - Brazil
[2] Univ Florida, Coll Dent, Dept Restorat Dent Sci, Gainesville, FL - USA
Total Affiliations: 2
Document type: Journal article
Source: Operative Dentistry; v. 44, n. 5, p. 499-509, SEP-OCT 2019.
Web of Science Citations: 0
Abstract

Objectives: To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the depth of cure and polymerization shrinkage stress of bulk-fill composites. Methods and Materials: Experimental bulk-fill composites were produced containing equal molar concentrations of either CQ-amine or CQ-amine/TPO. The degree of in-depth conversion through each millimeter of a 4-mm-thick bulk-fill increment was evaluated by Fourier transform near-infrared microspectroscopy using a central longitudinal cross section of the increment of each bulk-fill composite (n=3). Light-transmittance of the multi-wave light-emitting diode (LED) emittance used for photoactivation (Bluephase G2, Ivoclar Vivadent) was recorded through every millimeter of each bulk-fill composite using spectrophotometry. The volumetric shrinkage and polymerization shrinkage stress were assessed using a mercury dilatometer and the Bioman, respectively. The flexural modulus was also assessed by a three-point bend test as a complementary test. Data were analyzed according to the different experimental designs (alpha=0.05 and beta=0.2). Results: Up to 1 mm in depth, adding TPO to CQ-based bulk-fill composites increased the degree of conversion, but beyond 1 mm no differences were found. The light-transmittance of either wavelengths emitted from the multi-wave LED (blue or violet) through the bulk-fill composites were only different up to 1 mm in depth, regardless of the photoinitiator system. Adding TPO to CQ-based bulk-fill composites did not affect volumetric shrinkage but did increase the flexural modulus and polymerization shrinkage stress. Conclusion: Adding TPO to CQ-based bulk-fill composites did not increase the depth of cure. However, it did increase the degree of conversion on the top of the restoration, increasing the polymerization shrinkage stress. (AU)

FAPESP's process: 17/22161-7 - Development and characterization of dental resin materials photoactivated under WAVELENGHS between 495 and 750 nm
Grantee:Dayane Carvalho Ramos Salles de Oliveira
Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
FAPESP's process: 16/05823-3 - LOW INTENSITY LIGHT-CURING UNITS AND PHOTOINITIATION SYSTEMS ACTIVATED UNDER WAVELENGHS IN BETWEEN 495-750 NM FOR DENTAL RESIN MATERIALS
Grantee:Dayane Carvalho Ramos Salles de Oliveira
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 17/22195-9 - Development and characterization of bulk fill composites light cured using silver nanoparticles surface plasmon resonance as a photoinitiator system
Grantee:Mateus Garcia Rocha
Support Opportunities: Scholarships abroad - Research Internship - Doctorate