Effects of boundary condition on shrinkage vectors of a flowable composite in experimental cavity models made of dental substrates

Kaisarly, Dalia; El Gezawi, Moataz; Nyamaa, Indra; Roesch, Peter und Kunzelmann, Karl-Heinz (2019): Effects of boundary condition on shrinkage vectors of a flowable composite in experimental cavity models made of dental substrates. In: Clinical Oral Investigations, Bd. 23, Nr. 5: S. 2403-2411

Abstract

ObjectivesBond strength to enamel and dentin depends on the bonding approach or condition. This study investigated the effects of the boundary conditions, in terms of the bonding substrate and the bonding condition, on the shrinkage vectors of a flowable composite.Materials and methodsAn experimental cylindrical cavity (diameter=6mm, depth=3mm) consisting of the enamel floor and the surrounding dentin cavity walls was prepared for the enamel-floor group. Cylindrical cavities of the same dimensions were prepared with access from the occlusal enamel into dentin and served as controls. Each cavity model group was divided and bonded with two bonding conditions (n=9): a self-etch (Adper Easy Bond, 3M ESPE) and a total-etch approach (OptiBond FL, Kerr). The composite (Tetric EvoFlow, Ivoclar Vivadent) was mixed with glass beads, applied to the cavity, scanned twice by micro-CT (uncured and cured states). The scans were evaluated by rigid registration, sphere segmentation, and registration for computing shrinkage vectors.ResultsThe free surface of all restorations moved downward. The shrinkage vectors in the experimental cavity model pointed downward towards the enamel cavity floor, and the net axial movement was downward. In the control group, shrinkage vectors additionally moved upward, away from the cavity floor. The effect of the bonding substrate and the bonding condition was investigated for the shrinkage vectors and the axial movement (univariate ANOVA).ConclusionThe bonding substrate, enamel, influenced the shrinkage vectors' direction, while the bonding condition caused only variations in the magnitude.Clinical relevanceBonding to enamel influences shrinkage vectors' direction, while the bonding condition plays only a minor role.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 1432-6981
• Sprache: Englisch