Comparative Evaluation of the Compressive Strength of Self-Cure and Light-Cure Glass Ionomer-Based Cements in a Simulated Oral Environment: An In Vitro Study

Abstract

Background: Glass Ionomer Cements (GICs) are commonly used in pediatric restorative dentistry due to chemical adhesion, fluoride release and biocompatibility. Mechanical strength - particularly compressive strength is important when selecting GICs for stress-bearing restorations.

Aim: To compare the compressive strength of two self-cure and two light-cure glass ionomer-based restorative materials after storage in artificial saliva.

Materials and Methods: An in vitro study was performed on 20 cylindrical specimens prepared using prefabricated Teflon molds (4 mm diameter × 6 mm height). Subgroups (n = 5 each): A1 — ChemFil Rock (self-cure), A2 — GC Fuji IX GP Fast (self-cure), B1 — GC Fuji II LC (light-cure), B2 — Ketac N100 (light-cure). Specimens were prepared per manufacturer instructions, stored incommercially available artificial saliva at 37°C for 2 weeks, and tested for compressive strength using an Instron universal testing machine (cross-head speed 1.0 mm/min). Compressive strength was calculated in MPa. Data are presented as mean ± SD.One-way ANOVA (subgroup comparison) followed by Tukey’s HSD post-hoc test, and an independent t-test (Group A vs Group B) were performed (SPSS v22). Significance set at p ≤ 0.05.

Results: Means (MPa): A1 81.4 ± 2.30; A2 77.0 ± 1.58; B1 90.0 ± 1.58; B2 83.0 ± 1.58. One-way ANOVA: F(3,16) = 45.56, p = 4.63×10⁻8. Independent t-test (self- vs light-cure): t(18) = −4.65, p = 0.0002.

Conclusion: Light-cure glass ionomer-based cements showed significantly higher compressive strength than self-cure GICs under the conditions tested. GC Fuji II LC demonstrated the highest compressive strength among tested materials.