Final answer:
Using water, air, or a combination of both is necessary when polishing amalgam to prevent heat damage to the tooth and to manage the mercury component's toxicity. Dental amalgams are durable and cost-effective but have seen a decline in use due to health considerations.
Step-by-step explanation:
It is true that during the process of polishing amalgam restorations, dentists typically use a coolant such as water, air, or a combination of both. The use of a coolant serves to minimize the heat generated by the friction during polishing, which can damage the tooth and pulp if left unchecked.
Dental amalgams, which consist of a mixture of metals including silver, tin, copper, and approximately 50% mercury, require care when being polished to maintain the integrity of the restoration and to protect patient health due to the toxicity of mercury.
Over the years, there has been a significant decline in the use of amalgam due to health concerns about mercury. Still, it remains in use because it is a durable and cost-effective material with properties such as ease of manipulation that make it suitable for filling cavities. Meanwhile, alternative materials are being explored and used increasingly in dental practices.