Retentive Strengths of 4 Different Luting Cements

Objectives: Resin-modified glass-ionomer and compomer luting cements become more and more popular in daily dental practice. However, very little information is available about their luting ability. It was therefore the aim of this study to evaluate the retentive strength (RS) of two modern luting agents (FujiPlus/GC, DyractCem/DeTreyDentsply) and compare them to two traditional glass-ionomer cements (GICs: KetacCem/3M-ESPE, Fuji-I/DeTreyDentsply). Methods: Cylindrical abutments (6° angle of convergence) were machined of brass in heights of 4, 6 and 8 mm. Crowns (Phantom-Metall/Degussa) were fabricated on the abutments and sandblasted with 110 µm Al2O3. The luting cements were mixed according to the manufacturer's instructions. The crowns were seated with a constant pressure of 10 N for 10 min.. Then, the specimens (10 per series) were placed at 37°C for 20 min. prior to 24 h storage in water at 37°C. RS was determined after water storage and thermocycling (TC: 1000x 5-55°C), respectively in a Zwick 1454 universal testing device (crosshead speed 10 mm/min.). Data were subjected to non-parametric statistics. Results: RS ranged from 1.7 to 15.7 MPa. DyractCem showed the highest RS compared to all other luting cements used (p<0.05). FujiPlus showed significantly higher RS compared to KetacCem and Fuji-I (p<0.05). No statistical difference was found between KetacCem and Fuji-I (p>0.05). TC significantly decreased the RS for DyractCem (p<0.05), while TC significantly increased the RS for KetacCem, Fuji-I and FujiPlus (p<0.05). Conclusions: Within the limits of the study it can be concluded, that TC affects the RS of the investigated compomer luting cement, while the traditional GICs and resin reinforced GICs showed an increase in RS after TC. Further investigations are necessary, to prove the long term clinical success of modern compomer luting agents.