The use of zirconia for medical purposes was first proposed over fifty years ago, and the popularity of dental zirconia has increased over recent decades due to its excellent mechanical, biocompatibility, and aesthetic properties. To stabilise t-phase zirconia at room temperature, the addition of stabilisers such as yttria to pure zirconia crystals has been utilised, and 3 mol% yttria stabilised tetragonal zirconia polycrystal (3Y-TZP) has become a norm in dental ceramics for prosthetic restorations.

However, the major drawback of the older generation of 3Y-TZP is its high opacity, especially when compared with glass ceramics. To reduce the opacity of Y-TZP, various attempts have been tried out, such as reducing alumina additive, eliminating porosity, increasing the sintering density, reducing the grain size, and incorporating c-phase zirconia. The latest translucent Y-TZP (e.g., 4Y-TZP and 5Y-TZP) contains c-phase zirconia which needs a higher concentration of yttria than that of 3Y-TZP, and they exhibit comparable translucency with glass ceramics (e.g., lithium disilicate). Apart from that, multi-layered, graded, and nanoscale zirconia have also been introduced to the market as novel dental zirconia. The above-mentioned novel dental zirconia has exhibited improved translucency and/or mechanical properties and is considered sufficient for aesthetic rehabilitation. However, adequate clinical and technical protocols are needed to obtain good performance of these novel materials.

This Special Issue aims to gather original research, technical notes, and reviews related to the application of novel zirconia in dentistry. This Special Issue welcomes ageing behaviour, bonding, biological aspects, chemical ageing, and wear evaluation of novel dental zirconia. Laboratory and/or clinical evaluation of multi-layered, graded, and nanoscale zirconia is especially welcome.

Potential topics include but are not limited to the following:

• Challenges in bonding to novel zirconia
• Ageing behaviour of multilayer, graded, and nanoscale zirconia
• Zirconia implants
• Colouring procedure of novel zirconia
• Wear of zirconia prostheses and antagonistic tooth structure