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Internal adaptation of resin composites at two configurations: Influence of polymerization shrinkage and stress.
Dent Mater. 2016 Jun 29;
Authors: Han SH, Sadr A, Tagami J, Park SH
Abstract
OBJECTIVE: This study compared internal adaptation of composites under different C-factors and examined the relationship between internal adaptation and polymerization shrinkage parameters.
METHODS: Cylindrical cavities 3mm in diameter were prepared in 100 human third molars in two depths: 4mm high C-factor (H-CF) or 1mm low C-factor (L-CF). After adhesive application (Clearfil SE One, Kuraray Noritake), the composite was placed in two increments in three subgroups: Filtek Supreme (FS, 3M ESPE); Charisma Diamond (CD, Heraeus Kulzer); Amelogen Plus (AP, Ultradent); and as a single increment in two subgroups: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent) and Venus Bulk Fill (VB, Heraeus Kulzer). After thermo-mechanical load-cycles, imperfect margin percentage (%IM) was calculated using swept-source optical coherence tomography (SS-OCT) imaging. The relationships between %IM and linear shrinkage (LS) and shrinkage stress, measured under either zero-compliance (PS0) or compliance-allowed (PS) conditions were evaluated.
RESULTS: The %IM was significantly different between H-CF and L-CF groups. The %IM in H-CF turned out to be as groups CD, FS≤TB<AP, VB. The %IM in L-CF showed as groups CD, TB≤FS, AP<VB. There were significant correlations between shrinkage parameters and %IM, except between PS0 and %IM in L-CF.
SIGNIFICANCE: Internal adaptation in a high C-factor cavity was inferior to that in a low C-factor cavity for both conventional and bulk-filled composites. Internal adaptation, polymerization shrinkage, and stress were different among composite materials. Polymerization stress under the compliance-allowed condition showed significant correlations with internal adaptations in high and low C-factor cavities.
[cite source='pubmed']27372237[/cite] – as supplied by publisher]