In vitro degradation of cements: a comparison of three test methods

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Oral Health Research

Background:

• Luting cements are crucial for dental restorations, but their long-term stability in the oral environment is a concern.
• Predicting the disintegration rate of luting cements in vivo is essential for clinical success.
• Standardized in vitro testing methods are needed to accurately forecast cement performance.

Purpose of the Study:

• To evaluate three in vitro tests for their efficacy in predicting the disintegration resistance of luting cements.
• To compare the results of in vitro tests with in vivo disintegration rates.
• To identify the optimal in vitro test and storage medium for assessing cement stability.

Main Methods:

• Three in vitro tests were employed: weight loss, size reduction of cement films between glass flats, and transverse strength reduction.
• Cements were stored in distilled water (H2O) and varying concentrations of acetic acid (HAc): 0.1 M, 0.01 M, and 0.001 M.
• In vitro data were correlated with previously measured in vivo disintegration rates.

Main Results:

• Test No. 2, measuring the reduction in size of cement films, showed the highest correlation with in vivo disintegration.
• The optimal storage medium for Test No. 2 was found to be 0.01 M acetic acid.
• Other tested conditions (weight loss, transverse strength, different media) demonstrated lower predictive accuracy.

Conclusions:

• A specific in vitro test (size reduction between glass flats) in a defined acidic medium (0.01 M HAc) can effectively predict luting cement disintegration in the oral cavity.
• This method offers a reliable alternative for assessing cement durability compared to other in vitro approaches.
• Further validation may enhance its clinical applicability in dental material selection.