Title: 3335 - Microhardness of Self-adhesive Resin Cements Light-polymerized Through a Restorative Material
Carlos Eduardo Sabrosa (Presenter)
University of the State of Rio de Janeiro
Karen Geber, University of the State of Rio de Janeiro
Karen Mann, University of the State of Rio de Janeiro
Monique Castro, University of the State of Rio de Janeiro
Ricardo Herzog, University of the State of Rio de Janeiro
Objectives: Measure surface microhardness of five different self-adhesive resin cements light cured through a zirconium oxide (Lava™ Plus shade A2; 3M Oral Care; Germany) material in different thicknesses.
Methods: Five different self-adhesive resin cements 1- RelyX™ Unicem 2 Automix, 3M ESPE; 2- Maxcem Elite™ Chroma, Kerr; 3- G-CEM Link-Ace™, GC; 4- SpeedCEM Plus, Ivoclar and 5- Calibra® Universal, Dentsply were mixed according to manufacturer’s recommendation and dispensed into a 200µm thick ring. A glass slide as well as a transparent film were used in both top and bottom surfaces in order to separate the cement specimen after polymerization and allow testing. Specimens were separated into 3 groups: 1- control (0.0mm, LED directly onto specimen); 2- Lava™ Plus 0.5mm and 3- Lava™ Plus 1.5mm. An LED light curing unit (Elipar™ Deep Cure-S; 3M Oral Care) was used to light cure the specimens for 20 seconds of exposure following manufacture’s recommendation. Vickers Hardness (HV) was measured in a microhardness tester (M-400-G2; Leco, USA). Samples were stored in 100% humidity at 36°C and measured at 6 different spots after 10 minutes (immediate) and 24 hours. Means and standard deviations were calculated. Results were analyzed with ANOVA followed by Tukey HSD test (α=0.05).
Results: Means and standard deviations of Vickers Hardness (HV) are shown in Table 1.
Conclusions: Immediate microhardness of light-polymerized specimens decreased with increasing thickness of the zirconium oxide material tested except for SpeedCEM® Plus. RelyX™ Unicem 2 had significantly higher microhardness than all the other cements under all testing conditions. Microhardness increased after storage at 36°C for 24h for all cements tested, with RelyX™ Unicem 2 and G-CEM Link-Ace™ showing the highest percentage of increase. This indicates that an efficient self-curing has taken place.
|Thickness [mm]||Storage Time at 36°C||RelyX™ Unicem 2 Automix||Maxcem Elite™ Chroma||G-CEM Link-Ace™||SpeedCEM® Plus||Calibra® Universal|
|0.0||10 min||31.8 ± 1.1 A||25.9 ± 1.9 B||17.7 ± 0.5 D||17.2 ± 0.3 D||20.6 ± 1.0 C|
|0.5||10 min||32.8 ± 2.1 A||23.8 ± 2.6 B||16.8 ± 0.5 C||15.3 ± 2.0 C||14.7 ± 1.7 C|
|1.5||10 min||24.7 ± 2.0 A||18.7 ± 2.9 B||13.6 ± 1.4 C||17.0 ± 1.2 B||7.1 ± 0.7 D|
|0.0||24 h||44.3 ± 2.1 A||27.0 ± 1.4 B||25.7 ± 1.5 B||21.9 ± 0.6 C||22.1 ± 1.9 C|
|0.5||24 h||39.2 ± 1.7 A||28.1 ± 0.7 B||25.3 ± 0.7 C||21.5 ± 1.0 D||15.9 ± 1.6 E|
|1.5||24 h||37.0 ± 4.5 A||21.3 ± 0.8 B||20.4 ± 1.2 B||23.9 ± 3.0 B||10.1 ± 2.0 C|
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE