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AM of ceramic dental materials is still underdeveloped , mainly due to the difficulties to produce pieces with suitable surface finishing , mechanical properties and dimensional accuracy .
 manufacturing process: AM; material: ceramic dental materials; manufacturing process: surface finishing; concept or principle: mechanical properties; process characterization: dimensional accuracy
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 manufacturing process: AM; material: ceramic dental materials; manufacturing process: surface finishing; concept or principle: mechanical properties; process characterization: dimensional accuracy