Objective: The exploration of the digitized point indication process on 3D dental plaster cast models , and to study the effect of local optimization.
Subject and Method: With standardized manipulation and practices, reliable measures can be obtained from plaster casts. When indicating tooth cusps, the practitioner is aided by his stereoscopic vision and his professional intuition. Linear measurements with a caliper involve two landmarks simultaneously. 3D models are practically always represented on a (2D) flat screen and landmarks are indicated separately using local information only. Therefore, measurements based on digital models are fundamentally different from real world measurements. We propose a standardized 2D view and a local search algorithm for optimal point indication. Thirteen digital models where obtained from plaster casts (OrthoProof) and exported to a locally developed 3D point indication tool (Matlab R2008a) incorporating standard projection and standard projection combined with local search. Nine linear measurements between tooth cusps were obtained from the original plaster casts and from indications by two experienced orthodontists. Statistical analysis was based on descriptive statistics, correlation analysis and non-parametric Friedman's ANOVA with the Tukey-Kramer difference criterion.
Results: For four of the nine linear measurements, those based on the digital indications were significantly different from the manual measurements (p=0.05). The local search augmented the minimal test-retest correlation for the digital linear measurements from r=0.978 to r=0.998. The minimal correlation for a digital linear measurement between the two raters was r=0.960 for the standard projection and r=0.991 for the local search algorithm.
Conclusion: Linear measurements in the real world can differ significantly from measures obtained through the digital indication methods proposed. Through standardization extremely reliable digital measurements are achieved. Local search improves the reliability notably. The clinical relevance of the digital measures will be investigated in further research.
Original languageEnglish
JournalEuropean Journal of Orthodontics
Issue number2011
Publication statusPublished - 1 Jun 2011
EventUnknown -
Duration: 1 Jun 2011 → …

    Research areas

  • feature points, orthodontics, 3D digital

ID: 2125756