A study of distortion and surface hardness of improved artificial stone casts

1. The single-pour technique is as accurate as the double-pour technique except for point 6 (palatal point). Here the double-pour technique has greater accuracy. Impression material thickness over point 6 was approximately 15 mm. 2. The double-pour technique produced specimens which had superficial hardness values significantly higher than those of casts produced by the single-pour technique. 3. Specimens made with slurry water showed no greater distortion than specimens from other techniques. Surfaces of the specimens made with slurry water were significantly harder than those of specimens made with distilled water. Both types of specimens were made with the single-pour technique. 4. No significant difference in distortion was found in specimens produced with varying thickness of irreversible hydrocolloid impression material over the occlusal pins.