Accuracy of combining intraoral and facial scan in a single digital model of an orthodontic patient utilizing corresponding measurements on the model and on real photographs: A prospective cross-sectional study

Objectives

To validate the accuracy of integration of intraoral scan to the facial scan acquired by the EM3D application, utilising the Blue Sky Plan 4 software, creating a digital model of an orthodontic patient, by comparing the same linear measurements on real photographs and images from the digital model of the patient.

Material and methods

Thirty patients (20 females and 10 males; age range 12–30 years) undergoing orthodontic treatment with fixed appliances were recruited in this prospective cross-sectional study from December 2024 to February 2025. Five facial landmarks were marked on each patient: Tragion right, Cheilion right and left, Subnasale and Pronasale. Intraoral scan and facial scan were performed at the same appointment. Facial scan was conducted using an iPhone 13 Pro with the EM3D face scanning application which utilizes the iPhone's TrueDepth camera technology while the patient was smiling. The STL (Stereolithography) and OBG (Object) files (acquired from intraoral and facial scan respectively) were combined in a digital model using the Blue Sky Plan 4 software. Lateral and frontal photographs of the patient's face, while smiling, were also acquired. Eight linear measurements (Tragion right – bracket #11, Tragion right – incisal #11, Cheilion right – #13, Cheilion left – #13, Subnasale – #11, Subnasale – #21, Pronasale – #11, Pronasale – #21) were digitally performed on the real and digital photographs of the patients using the facial landmarks and certain points on teeth and braces. Paired sample t-test and Wilcoxon signed-rank test were used for statistical analysis.

Results

Significantly statistical difference was detected only in one (Cheilion right – #13) measurement (P = 0.004).

Conclusion

Combining intraoral and facial scan using a special software provides a clinically useful digital model of an orthodontic patient for diagnosis, treatment planning and outcome assessment.