In Vitro Comparison of the Performance of Hydrophilic and Conventional Hydrophobic Resin-Based Fissure Sealants

Abstract

Background: Hydrophilic sealants were developed to overcome hydrophobic sealant moisture sensitivity; however, there is still a limited understanding of their performance. This study aimed to compare microshear bond strength, penetration depth, and microleakage of hydrophilic UltraSeal XT hydro and hydrophobic Clinpro resin-based sealants placed in various surface conditions.

Methods: Seventy-two enamel slices and 60 molars were randomly assigned into two groups: Group 1 UltraSeal XT hydro and Group 2 Clinpro, which were further subdivided into three groups based on the enamel surface conditions (dry, slightly moist, and saliva-contaminated). After applying sealant and undergoing 5000 thermocycling cycles, microshear bond strength was tested. Additionally, penetration depth and microleakage were evaluated under a light microscope after staining with 50% silver nitrate solution.

Results: Group 1 demonstrated significantly higher microshear bond strength than Group 2 across all experimental conditions (P < .001). Both sealants showed the highest microshear bond strengths under dry conditions, followed by slightly moist and saliva-contaminated conditions (P < .001). The penetration depth between the two sealant types was comparable within each surface condition. However, both sealants showed significantly deeper penetration on dry enamel surfaces compared to slightly moist and saliva-contaminated surfaces (P < .001). Similarly, both sealants exhibited significantly less microleakage on dry enamel surfaces compared to slightly moist and saliva-contaminated surfaces (P < .001). While the mean microleakage value was similar between the two sealants under dry and saliva-contaminated conditions, Group 1 showed significantly lower microleakage than Group 2 under moist conditions (P < .001).

Conclusion: The hydrophilic UltraSeal XT hydro sealant exhibited superior bond strength compared to the hydrophobic Clinpro sealant across all surface conditions. On slightly moist surfaces, UltraSeal XT hydro showed significantly lower microleakage than Clinpro. Both sealants exhibited superior sealing and retentive ability on dry enamel surfaces compared to the other surfaces.

Keywords: Bond strength; Hydrophilic; Hydrophobic; Microleakage; Microshear; Penetration; Sealant.

Fig. 1

Overview of the experimental design.

Fig. 2

SEM photomicrography illustrating failure modes in both sealant types. (1 and 2) Cohesive and mixed failure in Group 1D. (3) Mixed failure in Group 1M. (4 and 5) Adhesive and mixed failure in group 1S. (6 and 7) Adhesive and mixed failure in Group 2D. (8 and 9) Adhesive and mixed failure in Group 2M. (10) Adhesive failure in Group 2S. (a) 90× and (b) 500× magnifications.

Fig. 3

Box-plot diagram illustrating unfilled area proportions between the two sealant types in each surface condition and within the same sealant types (same letter indicates no significant difference P > .05).

Fig. 4

Box-plot diagram illustrating microleakage proportions between the two sealant types in each surface condition and within the same sealant types (same letter indicates no significant difference P > .05).

Fig. 5

Stereomicroscopic images of microleakage obtained in the Groups (A) 1D, (B) 1M, (C) 1S, (D) 2D, (E) 2M, (F) 2S.