Premium
Effect of modulated photo‐activation on polymerization shrinkage behavior of dental restorative resin composites
Author(s) -
Tauböck Tobias T.,
Feilzer Albert J.,
Buchalla Wolfgang,
Kleverlaan Cornelis J.,
Krejci Ivo,
Attin Thomas
Publication year - 2014
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/eos.12139
Subject(s) - shrinkage , composite material , curing (chemistry) , materials science , polymerization , hardening (computing) , composite number , polymer , layer (electronics)
This study investigated the influence of modulated photo‐activation on axial polymerization shrinkage, shrinkage force, and hardening of light‐ and dual‐curing resin‐based composites. Three light‐curing resin composites ( SDR bulk‐fill, E sthet X flow, and E sthet X HD ) and one dual‐curing material ( R ebilda DC ) were subjected to different irradiation protocols with identical energy density (27 J cm −2 ): high‐intensity continuous light ( HIC ), low‐intensity continuous light ( LIC ), soft‐start ( SS ), and pulse‐delay curing ( PD ). Axial shrinkage and shrinkage force of 1.5‐mm‐thick specimens were recorded in real time for 15 min using custom‐made devices. Knoop hardness was determined at the end of the observation period. Statistical analysis revealed no significant differences among the curing protocols for both K noop hardness and axial shrinkage, irrespective of the composite material. Pulse‐delay curing generated the significantly lowest shrinkage forces within the three light‐curing materials SDR bulk‐fill, E sthet X flow, and E sthet X HD . High‐intensity continuous light created the significantly highest shrinkage forces within E sthet X HD and R ebilda DC , and caused significantly higher forces than LIC within E sthet X flow. In conclusion, both the composite material and the applied curing protocol control shrinkage force formation. Pulse‐delay curing decreases shrinkage forces compared with high‐intensity continuous irradiation without affecting hardening and axial polymerization shrinkage.