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In the production process of dental restorations, dental sintering paste is a key material that ensures the bonding strength between the ceramic layer and the substrate, and can be called the "invisible adhesive" that connects the various layers of the restoration structure. It forms a stable bond between ceramic powder and metal or zirconia substrate through high-temperature sintering process, directly affecting the strength and service life of the restoration.
In terms of composition, dental sintering paste is mainly composed of glassy ceramic powder, sintering aid, and coloring agent. Glass phase ceramic powder ensures the compactness after sintering, sintering aids reduce sintering temperature and promote interface fusion, and coloring agents can match the natural tooth color, making the restoration more aesthetically pleasing. According to the different substrate materials, sintering paste can be divided into metal substrate specific type and zirconia substrate specific type: metal substrate sintering paste needs to have the ability to react with metal oxides to form a chemical bonding layer; Zirconia based sintering paste focuses on physical infiltration with the surface of zirconia, enhancing adhesion through mechanical locking.
In clinical applications, the use of sintered paste requires strict process parameters. For example, when making a metal porcelain crown, it is necessary to uniformly apply sintering paste on the surface of the metal substrate, and then sinter it at a high temperature of 900-1050 ℃ to melt the paste and form an oxide film on the metal surface; The sintering of zirconia all ceramic crowns needs to be controlled at 850-950 ℃ to avoid high temperature induced zirconia phase transformation cracking. In addition, the coating thickness of the sintered paste should be controlled between 5-20 microns. Excessive thickness can easily cause the ceramic layer to peel off, while excessive thickness cannot form effective bonding.
High quality sintered paste can significantly improve the performance of restorations: after sintering, the flexural strength of restorations can be increased by more than 30%, and the bonding force between the ceramic layer and the substrate can reach more than 25MPa. At the same time, it has good wear resistance and biocompatibility, avoiding irritation to gingival tissue. With the development of digital restoration technology, the new nanoscale sintered paste has achieved more precise coating control, providing more reliable quality assurance for personalized restorations
