Final answer:
The preferred restoration for full coverage of a primary tooth is a stainless steel crown, due to its durability and ability to withstand chewing forces until the primary tooth is replaced by a permanent tooth.
Step-by-step explanation:
The type of restoration used for full coverage of a primary tooth is c) Stainless steel crown. Dental amalgam, while inexpensive and durable, contains approximately 50% mercury by weight, which poses concerns about toxicity. Composite resins and glass ionomer restorations are typically used for smaller cavities due to their aesthetic qualities and ability to bond directly to the tooth structure.
However, for full coverage, especially in cases where a primary (baby) tooth is severely decayed or damaged, a stainless steel crown is the preferred choice. This type of crown is able to withstand the forces of chewing, providing a durable and long-lasting restoration until the primary tooth naturally exfoliates and is replaced by the permanent tooth.