Evaluation of physical and mechanical properties of a strontium silicate-based sealer
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Abstract
OBJECTIVE: This study sought to evaluate the fundamental physical and mechanical properties of a novel endodontic sealer formulated with strontium silicates (Sr-Si sealer) and to compare its performance against a commonly used calcium silicate-based sealer (Ca-Si sealer). The aim was to identify potential advantages offered by the new material. METHODS: The elemental composition of both sealer materials was determined using energy dispersive X-ray spectroscopy (EDS). Following this, the particle size of each sealer was carefully evaluated using scanning electron microscopy (SEM). To assess macroscopic properties relevant to clinical use, flow, setting time, film thickness, and radiopacity were tested according to ISO 6876/2012. To simulate the behavior of the sealers during clinical application, a specifically designed pressure-flow test was conducted to quantify the forces required for initial sealer penetration into dentin tubules. Furthermore, the penetration depth of each sealer within the dentin tubules was observed using SEM on 20 extracted single-canaled teeth, which were obturated with either the Sr-Si or Ca-Si sealer (n=10 in each group) utilizing a hydraulic condensation technique to mimic clinical conditions. The resulting data were then subjected to statistical analysis using a t-test, with the level of statistical significance set at α = 0.05. RESULTS: The elemental analysis revealed that the Sr-Si sealer contained 5.7 weight % strontium, exhibiting a notably uniform and small average particle size of 1.59 ± 0.97 μm. In contrast, the Ca-Si sealer contained 13.8 weight % calcium and presented a larger and more variable average particle size of 8.05 ± 5.66 μm. The ISO testing demonstrated that the Sr-Si sealer had a significantly longer setting time, superior flow characteristics, and greater radiopacity (p<0.01). Moreover, the force required to initiate flow into simulated dentin tubules was significantly lower for the Sr-Si sealer (11.00 ± 0.74 N) compared to the Ca-Si sealer (21.51 ± 2.59 N). These in vitro findings were consistently corroborated by the in vivo observations on extracted teeth, which showed that the Sr-Si sealer achieved a significantly greater depth of penetration into the dentin tubules compared to the Ca-Si sealer. CONCLUSIONS: The Sr-Si sealer exhibited a small and homogeneous particle size, which correlated with its superior performance in flowability and dentin penetration. These findings suggest that this novel sealer may offer clinical advantages in achieving a more effective and predictable seal during endodontic treatment.
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2025