Editing Zirconium dioxide (section)

==3Y stabilised ZrO2 and 5Y stabilised ZrO2==
When ZrO₂ is stabilised by adding 3&nbsp;mol% of yttrium oxide (3Y-ZrO₂) at high temperatures (~1500&nbsp;°C), its mechanical properties such as [[fracture toughness]], [[flexural strength]], and [[hardness]] are significantly improved. This is because 3Y-ZrO₂ retains a metastable tetragonal phase at room temperature, which undergoes a stress-induced transformation to the monoclinic phase, leading to [[phase transformation toughening]] mechanism under high stress intensity.

In contrast, when ZrO₂ is stabilised with 5&nbsp;mol% of yttrium oxide (5Y-ZrO₂), it is primarily in the cubic phase, and does not undergo transformation toughening mechanism when  stress is applied. As a result, while 5Y-ZrO₂ exhibits better [[optical properties]] i.e, enhanced  translucency due to fewer grain boundaries to scatter [[light]], its mechanical properties ([[fracture toughness]], [[Strengthening mechanisms of materials|strength]], and [[hardness]]) do not improve in the same way as 3Y-ZrO₂.<ref>{{Cite journal |last1=Kongkiatkamon |first1=Suchada |last2=Rokaya |first2=Dinesh |last3=Kengtanyakich |first3=Santiphab |last4=Peampring |first4=Chaimongkon |date=2023-07-14 |title=Current classification of zirconia in dentistry: an updated review |journal=PeerJ |language=en |volume=11 |pages=e15669 |doi=10.7717/peerj.15669 |doi-access=free |pmid=37465158 |pmc=10351515 |issn=2167-8359 }}</ref><ref>{{Cite journal |last1=Sun |first1=Huijun |last2=Tabrizian |first2=Parinaz |last3=Qambrani |first3=Aqsa |last4=Jargalsaikhan |first4=Urangua |last5=Sui |first5=Tan |last6=Ireland |first6=Tony |last7=Su |first7=Bo |date=February 2024 |title=Bio-inspired nacre-like zirconia/PMMA composites for chairside CAD/CAM dental restorations |url=https://pubmed.ncbi.nlm.nih.gov/38040580/ |journal=Dental Materials|volume=40 |issue=2 |pages=307–317 |doi=10.1016/j.dental.2023.11.017 |issn=1879-0097 |pmid=38040580|doi-access=free }}</ref>