UBC Theses and Dissertations
Virtual interocclusal registration using intra-oral scanning Edher, Faraj
Purpose: The aims of this study were to assess if virtual interocclusal records taken at different locations on the arch have an effect on the alignment of the virtual casts, and to assess whether quadrant scans and full arch scans have an effect on the alignment of the virtual casts when articulated using virtual interocclusal records. Materials and Methods: Three sites of close proximity (SCP) and three sites of clearance were identified in each sextant on mounted zirconia master models. SCP and SC were confirmed using shimstock foil and transillumination of an interocclusal impression. Full arch and quadrant scans of the master models were taken using an intra-oral scanner and different virtual interocclusal record were taken. SCP and SC on each virtual alignment produced by the intra-oral scanner were compared to each other, and to an independent software. Sensitivity, specificity, and predictive values were utilized for the comparison Results: A change in the location of the SCP was found depending on the location of the virtual interocclusal record. The intra-oral scanner software displayed contacts showed higher sensitivity and negative predictive value (92.86% and 84.21% respectively) when compared to the contacts displayed on the independent software (69.05% and 70.45% respectively). However, the intra-oral scanner software had lower specificity and PPV (41.03% and 62.90% respectively) compared to the independent software (79.49% and 78.38% respectively). Quadrant scans showed higher sensitivity when compared to full arch scans. Conclusion: There is a significant difference in occlusal contacts obtained from bite scans of different segments. This difference is more obvious in full arch scans, in which a “tilting effect” towards the site of the bite scan can be observed. Occlusal contacts obtained from bite scans taken for quadrant virtual arches exhibited higher sensitivity when compared to those obtained from bite scans taken for full virtual arches.
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