Trueness Of Three Digital Methods For Obtaining Occlusal Relationships

Integrating the model scanning (MS) and intraoral scanning (IOS) techniques, a new digital method, MS+IOS, was proposed to obtain full-arch occlusal relationships more accurately. Three methods were used to obtain digital occlusal relationships on fifteen healthy participants: (1) IOS method: digital dental casts were automatically registered by using an intraoral scanner; (2) MS method: stone casts were digitized and registered by using a laboratory scanner; (3) MS+IOS method: digital dental casts from the MS method were registered with buccal occlusal records captured through the IOS method. Trueness was assessed by two factors: deviation values of the posterior occlusal surfaces (the primary indicator), and diagnostic tests for occlusal contacts. Additionally, the occlusal clearance values for each group were measured. The maxillary casts of the MS+IOS group (-105.88 ±109.17μm) exhibited significantly smaller deviations compared with the IOS group (-223.17 ±131.25μm,P<.05) in the occlusal direction. The MS group deviated 69.87 ±140.66μm toward the gingival direction. Concerning occlusal clearance, the IOS group had the highest average negative value (-200.66±174.76μm), the MS group had the highest average positive value (536.64±48.72μm, P<.05).The MS group exhibited the lowest sensitivity for occlusal contacts (P<.001). Compared with the IOS and MS methods, the full-arch occlusal relationship obtained by the MS+IOS method demonstrated better trueness. The MS method exhibited a trend of occlusal separation, and the lowest sensitivity to identify occlusal contacts.