You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is The dental stone model should be left undisturbed for ____________ until the material has set completely. and explain in detail?
If the inversion method is used, a mound of stone about 20 mm high is made on a flat surface, such as glass plate, with the remainder of the mixture or with a new mix using a lower W/P ratio. The filled impression, which should exhibit the initial set but not the final set, is then inverted over the mound of stone and the base is shaped with the spatula before the stone sets. The dental stone model should be left undisturbed for 45 to 60 min until the material has set completely. The dental stone model is now separated from the impression. When tooth preparations are involved, a smaller spatula may be used to deliver a much smaller amount of stone to fill the sites of the preparations and ensure complete filling before the remaining portion of the impression is poured. 
Phillips Science of Dental Materials ed 12 pg 192