Final answer:
The statement is false. It is recommended to fill the sink with water or use a towel to cushion the impact in case the dentures are dropped. This helps prevent damage to both upper and lower dentures during cleaning.
Step-by-step explanation:
The statement 'Place the upper denture in the sink while cleaning the lower denture' is false. When cleaning dentures, it is important to take precautions to avoid damaging them. One common practice is to fill the sink with water or place a towel in it when handling dentures. This is done so that if the dentures are dropped, the impact is less likely to cause them to crack or break. Therefore, both upper and lower dentures should not be placed directly in the sink; rather, they should be cleaned over a filled sink or a soft surface.