With the improvement of people's requirements for oral health, the demand for metal-free restoration is increasing, and various all-ceramic materials are introduced into the field of oral restoration. As one of the all-ceramic materials with good biological safety and high mechanical strength, zirconia ceramics have received extensive attention and research, and their applications in the field of dental prosthetics have become increasingly mature.
Although titanium as an oral implant material has been used in clinics quite maturely, due to the inevitable metal sensitization and the increasing requirements for metal-free repair, scholars are trying to find better biocompatibility and aesthetics. The implant material, zirconia is considered a reliable alternative.
Early planting applications: As early as the 1990s, zirconia was used in planting fields with its excellent mechanical and biological properties. The 3%-Y₂O₃ stabilized zirconia (alumina toughened zirconia, ATZ) ceramic with Al₂O₃ added has high flexural strength and is predicted to last for more than 20 years in the state of oral mastication. Similar to titanium implants, osteoblasts directly contact the surface of zirconia implants to obtain good stability and biocompatibility, and initiate the formation of new bones on the surface of the implants. However, some scholars believe that the sintered zirconia surface is smoother, which is not conducive to the bonding of bone tissues. Therefore, physical or chemical treatment on the surface of zirconia implants becomes a means to improve its osseointegration.
Late research: A number of in vivo and in vitro studies have shown that adding biologically active materials such as hydroxyapatite to the surface of zirconia implants, and roughening the surface of zirconia implants through acid etching, sandblasting, and laser etching techniques can promote cells to varying degrees And tissue adhesion. At present, more applications in the field of dental implants are zirconia all-ceramic personalized abutments and full crown restorations. Compared with the titanium abutment, the bacterial adhesion level is low, and combined with the individual design, the abutment has good aesthetics and stability. The edge suitability of the zirconia all-ceramic crown is better than that of the titanium abutment-all-ceramic crown. The amount of bacteria on the surface is lower than that of the titanium abutment. This conclusion is consistent with the results of many studies comparing the efficacy of zirconia all-ceramic crowns and metal-ceramic crown restorations.
Future expectations: It is worth noting that the inclination angle of the implant abutment, the connection method with the implant, and the implant-abutment design have an impact on the stress distribution of the zirconia porcelain abutment and the bone wall around the implant. Clinically, the most suitable abutment should be selected according to the patient's condition. However, the observation time of animal in vivo and clinical application research on zirconia implants and abutments is relatively short, and its long-term efficacy and scientificity need to be further evaluated.
