Hi doctor, I recently got a night guard made using an old dental cast that had some visible dust/stains. Actually I had kept it open n it was lying here n there unchecked My dentist saw the pics of guard n said its okay to use- I expected them to clean it n then use but shockingly the cast has same stains like before Now the guard fits perfectly and I have cleaned it thoroughly multiple times with soap and water but still i am unhappy with the fact that cast was kept dirty- they charged me same amount so i wish i had given fresh impression Please help me get peace of mind since i am not able to make mind to wear it