Three-Dimensional Accuracy of Digital Bite Registration Across Eichner-Based Dentition Patterns: An In Vitro Comparison of Three Intraoral Scanning Systems.

AIM: To determine whether three-dimensional digital bite-registration accuracy differs among three intraoral scanning systems across five predefined Eichner-based dentition patterns. MATERIALS AND METHODS: Typodont master models with a second-molar-to-second-molar baseline dentition were modified into five Eichner-based patterns (A1, A3, B1, B2, and B4). The prepared model pairs were digitally registered with an ATOS Triple Scan industrial scanner and GOM Inspect Professional 2020 using a 3-2-1 alignment and local best-fit matching strategy to create pattern-specific articulated reference datasets. For each pattern-system combination, ten complete scan sets were acquired (n = 150), each consisting of maxillary and mandibular scans plus bilateral posterior buccal bite scans under a standardized 3 kg (29 N) occlusal load. Threedimensional discrepancies between IOS-derived and reference datasets were assessed at five mandibular positions. The primary outcome was a scan-set-level overall displacement derived from the five position-level Euclidean displacement values. RESULTS: Scanning system, dentition pattern, and their interaction significantly affected the primary outcome. System-related differences were detectable in A1 and A3, attenuated in B1, and no longer clearly separated in B2 after multiplicity adjustment. The clearest separation was observed in B4, the condition without posterior support zones. CONCLUSION: Within the limitations of this in vitro study, digital bite-registration accuracy depended on both scanning system and Eichner-based dentition pattern. Reduced dentitions should not be treated as a uniform category when evaluating digital interarch registration.