Effects of restoration and substrate on polymerization contraction stress of dental composites.

Full Abstract

The aim of this study was to treat both restoration and substrate as a combined factor (RS-factor) to complement the popular C-factor in prediction of polymerization contraction stress (PCS). A simple model consists of a uniaxial restoration with a curing composite sandwiched between two solid mountings (substrates). By using the equal stress principle and taking into account substrate deformation, a set of equations were developed and solved, resulting in a mathematical relationship between PCS and the size and stiffness of the substrate and the restoration. The strain gage method was used to experimentally assess the PCS of a light-cured composite encircled in an aluminum ring. Differently sized inserts made of cured composites and glass were placed in the center of the ring to control the thickness of the composite to be cured and created different RS factors as well as C-factors. According to the model, a restoration with a small RS-factor will produce a high PCS. The model also predicts that a restoration with a small C-factor will have a high PCS because of the compliance of substrates. These predictions were tentatively confirmed by the strain gage measurements. A higher PCS was detected when a smaller insert was used, which created a smaller RS-factor or C-factor, or when a glass insert was used instead of a less stiff composite insert, in which the former created a smaller RS-factor. The RS-factor may be a dominant factor in determining the PCS outcome in some special cases. Copyright 2008 Wiley Periodicals, Inc.

Author information

Author/s: Feng, L (L); Nunez, R (R); Carvalho, R (R); Suh, B I (BI);

Affiliation: Department of Research and Development, Bisco, Inc., Schaumburg, Illinois, USA. lfeng(-atsign-)bisco.com

Journal and publication information

Publication Type: Journal Article

Journal: Journal of biomedical materials research. Part B, Applied biomaterials (J Biomed Mater Res B Appl Biomater), published in United States. (Language: eng)

Reference: 2009-Feb; vol 88 (issue 2) : pp 482-91

Dates: Created 2009/01/14; Completed 2009/03/05;

PMID: 18561293, status: MEDLINE (last retrieval date: 3/10/2009, IMS Date: 10 Mar 2009 00:00:00)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

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Associated Chemicals: Dental Materials (0) ; Polymers (0)

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