The Reliability and Validity of Little's Irregularity Index Assessment

the primary aim of the current study was to estimate the validity, reliability, and repeatability of LII measurements made directly on digital models compared to those made on traditional plaster models. As a secondary aim, the same comparisons will also performed between digital photographs of study models and their corresponding plaster models.

Inclusion criteria

• Standardized study models for patients with a full set of permanent teeth (the third molars are not considered).
• All study models for patients with Angle class I malocclusion.
• All study models for patients with mild to moderate anterior teeth crowding in both arches
• Corresponding standardized direct scanned intraoral digital models for all selected study models
• Corresponding standardized digital photos for all selected study models
• Corresponding standardized digital intra-oral photos for all selected study models

Exclusion criteria

• Damaged or distorted study models
• Unclear or distorted digital models (STL file)
• Unclear or distorted digital photos of study models (JPG File)
• Unclear or distorted intra-oral photos (JPG File)