Validity of teeth and arch measurments on conventional versus 3Dmodels

Objective:The introduction of virtual study models may allow the use of a fully electronic patient but the question is the accuracy and diagnostic capabilities of these models. Our aim was comparison of validity of teeth and arch measurements on Conventional and 3D models.

Methods: Twenty setups of upper and lower casts using artificial teeth corresponding to various malocclusions were created. Impressions were taken of them providing 20 plaster and 20 virtual orthodontic models. Values of tooth size were calculated from the isolated artificial teeth out of setups also on both set of models. Intermolar and canine width were calculated on models and dentics . The resulting values were compared using intraclass correlation coefficient, t-test and Daulberg method.

Results: Results demonstrated a high correlation between methods (0/918-0/9972) but a statistically significant difference compared to gold standard was seen in molar, premolar and inter canine width for conventional models also in all measurements for the 3D models(Least incisors/ most inter canine width). In tooth size measurements digital and plaster models were comparable .

Conclusions: Still Conventional method is the most accurate method for space analysis. But digital models are clinically acceptable.