This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Gold restoration cemented with zinc polycarboxylate usually fractures at which interface? 
Select and explain. 
A. Cement-prosthesis, B. Cement itself, C. Tooth structure - cement, D. Prosthesis failure
A: Cement-prosthesis
Answer: A: Cement-prosthesis 
Explanation: Zinc polycarboxylate has ability to bond chemically with tooth structure so less chance of failure at tooth cement inteface
In case of gold restorations usually adhesive failure occurs at the interface b/w gold & cement
In case of non-precious metals usually cohesive failure occurs b/w cement layer itself.