Clinical Performance of CAD/CAM Hard Hybrid Ceramic Inlays Versus Resin Composite Inlays in Vital Molars With Extensive Occluso-Proximal Cavities: Two-Year Randomized Clinical Trial

A wide variety of materials is now available for the fabrication of indirect restorations used to manage extensive carious lesions, including high-strength ceramics, hybrid ceramics, and resin-composite blocks. Each material offers distinct advantages in strength, wear resistance, aesthetics, and bonding performance, thereby expanding treatment options for severely compromised posterior teeth. However, these differences in mechanical and optical behavior, marginal adaptation, and long-term durability under functional stresses complicate clinical material selection.

Limited data is available comparing the clinical performance of these materials, particularly in large cavities in these regions. More information is needed on how they prevent post-treatment sensitivity, maintain edge quality, and resist discoloration, wear, and fractures.

Though short-term studies indicate excellent survival rates and aesthetic results for CAD/CAM hybrid ceramic inlays (more than 90% survival after two years), and systematic reviews imply that CAD/CAM resin composite inlays match ceramic restorations (success rates ranging from 85.7% to 100% for composites versus 93.3% to 100% for ceramics). There is a lack of direct clinical comparisons between these two material types in vital molars with occluso-proximal cavities. Much of the existing research is constrained to onlay designs or mixed-material groups, creating a significant gap in understanding which CAD/CAM block type delivers superior long-term performance for inlay restorations in vital teeth.