Incremental filling technique and composite material--part II: shrinkage and shrinkage stresses.
Oper Dent
; 39(2): E83-92, 2014.
Article
em En
| MEDLINE
| ID: mdl-24125075
ABSTRACT
OBJECTIVES:
Finite element analysis (FEA) was used to study polymerization shrinkage stress in molars restored with composites and to correlate those stresses with experimentally measured tooth deformation.METHODS:
Three composites (Filtek LS, Aelite LS Posterior, Filtek Supreme) and three filling techniques (bulk, 2.0-mm increments, and 1.0-mm increments) for restoring a molar were simulated in a two-dimensional FEA. Polymerization shrinkage was modeled using post-gel shrinkage, which was measured using the strain gauge technique (n=10). Cuspal tooth deformation, measured at the buccal and lingual surfaces with strain gauges in a laboratory study, was used to validate the analysis. Residual shrinkage stresses were expressed in modified von Mises equivalent stresses. Linear Pearson correlations were determined between the laboratory and FEA results.RESULTS:
Post-gel shrinkage values (in volume %) were Filtek LS (0.11 ± 0.03) < Aelite LS Posterior (0.51 ± 0.02) < Filtek Supreme (0.62 ± 0.09). The 1.0-mm increment filling caused substantially higher stresses and strains in the cervical enamel region. Significant correlations were found between elastic modulus and FEA strain, elastic modulus and FEA stress, post-gel shrinkage and FEA strain, post-gel shrinkage and FEA stress, FEA strain and cuspal deformation by strain gauge, and FEA stress and cuspal deformation by strain gauge (p<0.05).CONCLUSIONS:
Increasing the number of increments and high post-gel shrinkage and/or elastic modulus values caused higher stresses in the remaining tooth structure and tooth/restoration interface. Cuspal deformation measured with the strain gauge method validated the finite element analyses.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Resinas Compostas
/
Preparo da Cavidade Dentária
/
Restauração Dentária Permanente
Limite:
Humans
Idioma:
En
Revista:
Oper Dent
Ano de publicação:
2014
Tipo de documento:
Article