4829
The results showed significantly higher implant stability for the Co-Cr-Mo alloy with an addition of 0.04 % Zr after eight weeks of healing in rabbits , while no major differences were observed in the amount of bone formed around the implants .
 implant, alloy, Zr, bone, implants
Please list all entity words in the text that fit the category. Output format is "word1, 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:
 implant, alloy, Zr, bone, implants