Evaluation of Impression Accuracy With Penetration Depth Under Moisturized Condition

Objectives: A Main function of impression-material is to penetrate into margin area and take an accurate impression. However, moisturized oral environment makes it difficult for silicone impression-material to penetrate due to its hydrophobic nature. In order to solve this issue, recent silicone impression-materials have higher hydrophilic property. However, it is difficult to estimate effort in actual impression taking. The aim of this study was to examine the penetration depth (PD) of impression-material under moisturized condition against tooth-abutment-model to evaluate its accuracy.
Methods: Four silicone impression-materials [FusionII-Monophase (FII-M, GC Corporation), Imprint4-Regular (I4-R, 3M-ESPE), AquasilUltra-Monophase (AU-M, Dentsply) and ExamixFine-Regular (EF-R, GC Corporation)] were examined. The four-tooth –resin-model has 2 abutments (Abutment-1; 8mm diameter and Abutment-2; 4mm diameter) in the middle and each abutment has 0.5mm thickness and 8mm depth valley surround that was created. That model was stored in35^oC water-bath. Each impression-material was extruded into metal impression tray (ImpressionTray-No.32, GC Corporation) and immersed into 35^oC water-bath after 40sec. from extruding. Five sec. later, the tooth model was placed over impression-material and load 300g force was applied for 15 sec to take impression in water-bath. After cure, PD of impression-material was measured as length of material penetrated into 0.5mm thickness valley surround both of Abutment-1 and Abutment-2 and statistically analyzed (ANOVA, p<0.05).
Results: Mean values of PD including standard deviations were shown in following table; (n=3). At Abutment-1, PD of FII-M and AU-M were significantly deeper than others. At Abutment-2, PD of FII-M was significantly deeper than others.
Conclusions: FII-M has higher PD for both cases and it suggests FII-M has efficient hydrophilic property with Self-Wetting Technology which makes material auto-hydrophilic compared with traditional surfactant addition technology and may result in more clinically accurate impression.