Setting behaviour of luting cements monitored by an ultrasonic method

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• Luting cements are crucial in dental restorations, requiring precise setting behavior and mechanical properties.
• Accurate monitoring of cement setting is essential for ensuring long-term restoration success.
• Traditional methods for assessing cement setting can be time-consuming or destructive.

Purpose of the Study:

• To monitor the setting behavior and elastic modulus of luting cements.
• To evaluate the efficacy of an ultrasonic device for characterizing cement hardening.
• To compare the elastic moduli of different luting cements over time.

Main Methods:

• Utilized an ultrasonic device (pulser-receiver, transducers, oscilloscope) to measure sound wave transit times through cement specimens.
• Calculated sonic velocities (longitudinal and shear waves) from transit times and specimen thickness.
• Determined the elastic modulus using calculated sonic velocities and employed ANOVA and Tukey HSD tests for statistical comparison.

Main Results:

• Ultrasound energy absorption was high in early setting stages, with sound waves strengthening as cements hardened.
• Sound velocities increased with cement hardening, showing variations among different luting cements.
• Mean elastic moduli ranged from 2.9–9.9 GPa at 15 min, 14.4–20.3 GPa at 24 h, and 12.1–15.9 GPa at 1 month.

Conclusions:

• The ultrasonic method effectively monitored the setting behavior and elastic modulus of luting cements.
• Distinct differences in setting processes and elastic modulus development were observed among the tested luting cements.
• This non-destructive ultrasonic technique provides a clear definition of luting cement setting processes.