Reliability of planned occlusal contacts in complete arch rehabilitations at increased vertical dimension: A clinical comparison of intraoral scanning and jaw tracking protocols.

STATEMENT OF PROBLEM: Various digital workflows are available to capture the maxillomandibular relationship at an increased vertical dimension, including the use of intraoral scanners (IOSs) and optical jaw tracking systems. However, limited evidence exists for the virtual determination of an increased vertical dimension using jaw-tracking devices.

PURPOSE: The purpose of this clinical study was to compare the acquisition of the maxillomandibular relationship at an increased vertical dimension with the virtual determination through a jaw-tracking system and by using an IOS.

MATERIAL AND METHODS: Maxillary and mandibular digital scans were obtained for a total of 40 participants using an IOS (TRIOS 4; 3Shape A/S). The scans were duplicated, and maxillomandibular relationships were recorded at maximum intercuspation (MIP) and centric relation (CR) positions at an increased vertical dimension using a leaf gauge. Casts articulated in MIP were used to record patient jaw motion with a jaw tracking system (Modjaw; Modjaw). The jaw tracker's software program was used to virtually determine the maxillomandibular relationship at an increased vertical dimension similar to that achieved with the leaf gauge by replicating the recorded hinge movement. Using the IOS-acquired and the virtually determined records, 2 complete arch evaluation restorations were fabricated for each participant and fitted to their existing dentition. The restorations were evaluated intraorally using articulating film and an occlusal analysis system (T-Scan Novus; Tekscan). Contacts were assessed by 2 calibrated examiners, with the virtual design serving as the reference standard. Patient comfort was evaluated using a visual analog scale. Data were analyzed using 2-way ANOVA and the Levene test, followed by multiple post hoc comparisons (α=.05).

RESULTS: No significant difference was found in the mean proportion of true occlusal contacts between the restorations fabricated using the evaluated methods as assessed using the articulation film (P>.05) A lower mean number of false occlusal contacts was observed in restorations fabricated using the virtually determined increased vertical dimension via jaw tracking, compared with those fabricated using IOS-acquired records (P<.05). When occlusal contacts were evaluated using the occlusal analysis system, the restorations fabricated based on jaw tracking records demonstrated a significantly higher proportion of true occlusal contacts (P<.05). No significant differences between the investigated methods were observed in patient satisfaction or occlusal force distribution (P>.05).

CONCLUSIONS: Virtual determination of the maxillomandibular relationship at an increased vertical dimension using jaw-tracking records constitutes a clinically feasible method of fabricating complete arch restorations and is comparable with the acquisition of an increased vertical dimension using an IOS.