Water-induced Effects on the Hardness and Modulus of Contemporary Sealants Derived from Instrumented Indentation Testing (IIT).

Aim: To compare the mechanical properties of four different types of contemporary fissure sealants before and after water storage employing a modern instrumented indentation testing (IIT) method.

Materials And Methods: Four different types of materials used in everyday practice were deliberately selected. Fissurit (FIS) is a highly filled resin, Embrace (EMB) is a bisphenol A (BPA)-free unfilled resin, Helioseal (HEL) is an unfilled resin, and Riva Protect (RIV) is a glass-ionomer material. Six cylindrical specimens from each material were prepared (: 3 mm, : 15 mm), and Martens hardness (HM), elastic modulus (), elastic index (), and Vickers hardness (HV) were determined employing an IIT machine according to International Organization for Standardization (ISO) 14577:2015. Then, the samples were stored in water at 37°C for 48 hours and measured again at the same surface. The mechanical properties tested (HM, , , and HV) were statistically analyzed by two-way repeated measurements analysis of variance (ANOVA) employing materials and conditions as discriminating variables. Statistically significant differences were identified by Tukey's post hoc multiple comparison test. In all cases, a 95% level of significance was set ( = 0.05).

Results: Statistically significant differences in selected mechanical properties were allocated among materials tested. The artificial aging had a detrimental effect on HM, , and HV apart from for FIS, EMB, and HEL. In contrast, no significant differences were identified for RIV before and after water storage for all aforementioned properties apart from .

Conclusion: Significant differences were identified in mechanical properties among materials tested and thus differences in their clinical behavior are anticipated.

Clinical Significance: This study contributes to the understanding of the mechanical properties of different dental sealants with respect to water contact, which may influence the choice by the therapist.