Final answer:
Zinc phosphate cement is not ideal for cementing ceramic restorations due to its low pH, poor aesthetics, and inferior bonding properties compared to resin cements.
Step-by-step explanation:
Zinc phosphate cement is considered to have unfavorable qualities for permanent cementation of ceramic restorations. Its disadvantages include a low initial pH, which can be harmful to pulp, and poor aesthetics, which is particularly significant in cases where the ceramic restoration is translucent and the cement color may show through. Additionally, zinc phosphate cement has inferior adhesion to tooth structure and restorative material compared to other modern luting agents, such as resin cements, which offer better mechanical properties, aesthetics, and a supportive bond to the tooth's structure.