Adhesion to new CAD/CAM composite resin block

Abstract: Application of CAD / CAM technology has resulted in the use of several new dental materials for prostheses. Since 2014, CAD/CAM resin crown began to be introduced into public insurance system in Japan. After that, the application gradually expanded to premolar and molar, and now more than one million clinical applications have been made annually. CAD/CAM composite resin blocks used for CAD/CAM resin crowns have superior physical properties to conventional composite resins by polymerizing under optimum conditions of high temperature and high pressure to improve the polymerization degree of monomers and the silane coupling treatment of the filler. On the other hand, adhesion with adhesive resin cement is difficult because there are almost no resin surfaces effective for adhesion. Therefore, it is necessary to adhere to the filler similarly to the ceramic material. Some studies have reported that several surface treatments are required on the crown inner surface before cementing. That is, performing air abrasion, phosphoric acid cleaning, and silane coupling treatment is effective for adhesion to adhesive resin cement. At present, more than 20 kinds of resin blocks are on the market. CAD/CAM composite resin blocks have various different characteristics because the constituent components such as size, shape and content ratio of filler are different for each product. It is important for dentists to clinically understand that the adhesion to CAD/CAM composite resin blocks differs depending on the type of adhesive resin cement.