Investigation of digital and conventional methods for verifying the fitness of CAD/CAM crowns on various abutment

Purpose. To evaluate the marginal and internal compatibility of computer-aided design and computer-aided manufacturing crowns produced via a digital workflow using an intraoral scanner, and to compare this digital-detection technique with the conventional fit test using silicone rubber (silicone-compatibility technique) on various abutment. Methods. Implant screws were placed in the maxillary right central incisor and mandibular right first molar of reference models. Digital scans were acquired using an intraoral scanner, and abutments were prepared. Twenty-four crowns with a cement space of 70 µm were fabricated from the digital file of the abutment. The crown’s inner surface, abutment, and occlusal surface were scanned. The gaps between the crown and abutment were measured using stereoscopic image analysis software based on standard triangulated language data, and the accuracy of the fit was verified using silicone rubber. Results. Significant differences (P < 0.05) were observed between the silicone-compatibility and digital-detection techniques for the maxillary right central incisor at the center of the incisal edge (c) and lower region of the palatal access hole (e), and between the occlusal surface (d, f) and central tooth axis (g) of the mandibular right first molar. The digital-detection technique yielded values closer to 70 µm for the cement space. The values measured using the silicone-compatibility technique exhibited greater variation than those measured using the digital-detection technique. Conclusions. The novel digital-detection technique had superior or equivalent performance compared to the silicone-compatibility technique and could therefore be beneficial for verifying crown fitness accuracy.