The purpose of this study is to evaluate the validity, reliability and reproducibility of digital models obtained from iTero® and Lava Digital® in comparison with traditional plaster models.

The primary objective of this study is to evaluate the validity, reliability and reproducibility of the dental measurements obtained on the digital models with iTero® in comparison with those obtained on the plaster models (gold standard) and on the digital models with Lava Digital®.

The secondary objective is to compare two different impression materials (i.e. alginate and polyvinylsiloxane (PVS)) and determine whether the impression material used affects the accuracy of the measurements.

Statistical analysis:

• Intraclass correlation coefficient (ICC) will be used to evaluate the intra- and inter-operator reliability of the measurements for each method, i.e. the plaster models and the digital models.
• A paired t-test will be used to determine the validity of the digital measurements with iTero®, and to compare the impression materials (alginate and PVS).
• A Bland-Altman plot will also be used to compare the two digital methods (Lava Digital® et iTero®) with the plaster models.
• Dahlberg coefficient will be used to evaluate the technical error associated with the measurements that will be made.

Inclusion Criteria:

• Aged between 12 and 30 years old (male or female)
• complete permanent dentition from first molar to the other first molar
• no interproximal modifications (e.g. decay, large restorations, abnormal tooth morphology) which could affect the mesio-distal width of the teeth

Exclusion Criteria:

• Dentition with severe crowding (that could therefore affect the mesio-distal width of the teeth)

Patients requiring an orthodontic treatment from the Orthodontics clinic of the University of Montreal