Marginal integrity of different resin-based composites for posterior teeth: an in vitro dye-penetration study on eight resin-composite and compomer-/adhesive combinations with a particular look at the additional use of flow-composites

Abstract

Objective: To determine improvements in marginal adaptation of resin-based composite restorative systems by means of flow-composites (Solitaire 2/Gluma Solid Bond, Solitaire 2/Flow Line/Gluma Solid Bond, Point 4/Optibond Solo Plus, Point 4/Revolution/Optibond Solo Plus) and to determine the equality of simplified bonding systems (Solitaire 2/Gluma Comfort Bond, Tetric Ceram/Tetric Flow/Excite, Dyract AP/Prime & Bond NT/NRC, Pertac II/Prompt-L-Pop) in marginal gap formation. Methods: The marginal dye penetration (2% methylene-blue) was investigated separately for the approximal boxes of Class II mod-cavities with one cervical margin of the approximal box within enamel, the other within cementum. The surface analysis determined the percentage of dye-penetrated cervical and lateral margins of the approximal boxes, while the in depth investigation reported the mean dye penetration (mm) at both different cervical margins. Results: After thermocycling (5000×, 5–55°C) the percentage of dye penetration at the cervical cementum margins ranged from 16.5±5.9% (Solitaire/Flow Line/Gluma Solid Bond) to 82.8±5.7% (Pertac II/Prompt L-Pop), for the cervical enamel margins from 10.1±5.2% (Dyract AP/NRC/P & B NT) to 72.7±7.9% (Pertac II/Prompt L-Pop), and for the lateral enamel margins of the approximal boxes from 4.8±2.3% (Dyract AP/NRC/P & B NT) to 53.9±6.8% (Pertac II/Prompt L-Pop). In the in-depth dye penetration investigation the mean dye penetration ranged from 0.2±0.2 mm (Point 4/Revolution/Optibond Solo Plus) to 1.7±0.2 mm (Pertac II/Prompt L-Pop) at the cementum margins. At the enamel margins only Pertac II/Prompt L-Pop and Solitaire 2/Gluma Solid Bond showed mean in depth dye-penetrations deeper than 0.1 mm. Significance: Pertac II/Prompt-L-Pop showed a statistically significant (significance level α=0.05, Wilcoxon test) higher percentage of dye-penetrated margins than most of the other restorative systems.