Clinical accuracy and reproducibility of virtual interocclusal records.

STATEMENT OF PROBLEM: Although in vitro studies have investigated the accuracy of virtual interocclusal records, clinical research on their ability to register virtual dental casts accurately is lacking. PURPOSE: The purpose of this clinical study was to evaluate the accuracy and reproducibility of the virtual interocclusal records of an intraoral scanning system compared with conventional polyvinyl siloxane (PVS) interocclusal records. MATERIAL AND METHODS: Three conventional interocclusal records followed by 3 virtual interocclusal records per side per participant were made in 10 participants. Three sites of close proximity (SCP) and 3 sites of clearance (SC) per side per participant were identified on the transilluminated conventional interocclusal PVS records for a total of 60 SCP and SC. The presence or absence of these sites on the virtual interocclusal records was analyzed by using an independent software program. RESULTS: The sensitivity for correct identification in the virtual interocclusal record was 87%, and its specificity was 95%. The positive predictive value was 95%, and the negative predictive value was 88%. For reproducibility, 74% of the SCP were detected consistently for all 3 repeated scans, and 92% of the SCs were identified accurately. CONCLUSIONS: The accuracy of virtual interocclusal records in identifying interocclusal contacts is clinically acceptable. However, the method tends to miss interocclusal contacts rather than introducing false ones and can result in perforations between the opposing virtual casts. Repeated buccal occlusal scans made of the same side showed fair reproducibility, and this aspect would benefit from further investigation.

The accuracy of virtual interocclusal registration during intraoral scanning.

STATEMENT OF PROBLEM: Evidence on the accuracy and reproducibility of the virtual interocclusal registration procedure and recommendations as to how to make a virtual interocclusal record are lacking. PURPOSE: The purpose of this in vitro study was to assess whether virtual interocclusal registration records made at different locations around the arch affect the alignment of virtual casts, and to assess whether quadrant and complete arch scans have different effects on cast alignment when they are articulated with virtual interocclusal records. MATERIAL AND METHODS: Three sites of close proximity (SCPs) and 3 sites of clearance (SCs) were identified in each sextant of mounted zirconia master models. The SCPs and SCs were confirmed by using shimstock foil and the transillumination of an interocclusal impression. Complete-arch and quadrant scans of the master models were made with an intraoral scanner and registered with different virtual interocclusal registration records. The SCPs and SCs indicated by the scanner's software and by independent software were compared according to the sensitivity, specificity, and predictive values of each method. RESULTS: Changed locations of SCPs were found depending on the location of the virtual interocclusal registration record. The intraoral scanner's software contacts had a higher sensitivity of 92.86% and a negative predictive value of 84.21% than the contacts revealed by the independent software that exhibited a sensitivity of 69.05% and a negative predictive value of 70.45%. However, the intraoral scanner software had a lower specificity of 41.03% and a positive predictive value of 62.90% compared with the independent software, which exhibited a specificity of 79.49% and a positive predictive value of 78.38%. The quadrant scans had a higher sensitivity than did the complete-arch scans. CONCLUSIONS: Different occlusal contacts are obtained from interocclusal registration scans in different segments of the dental arch. The difference is more obvious in complete-arch scans, where a tilting effect toward the site of the interocclusal registration scan was observed. Occlusal contacts obtained from interocclusal registration scans for quadrant scans had a higher sensitivity than did those for complete-arch scans.