Three-dimensional digital assessment of typodont activations

Area of Science:

• Orthodontics
• Biomechanical Engineering
• Dental Education Technology

Background:

• Wax typodonts are standard pre-clinical tools for studying orthodontic force systems.
• Current typodonts lack the ability to quantify complex, statically indeterminate tooth movements.
• Accurate measurement of three-dimensional (3D) tooth displacement is crucial for research and education.

Purpose of the Study:

• To develop an innovative analogue-to-digital typodont system.
• To enable precise quantification of individual tooth movements in 3D.
• To analyze the effects of various archwire activations on typodont teeth.

Main Methods:

• Utilized Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) for system development.
• Tested multiple archwire activations including expansion, squaring, tapering, asymmetrical forms, and reversed curve of Spee.
• Assessed 3D tooth movements using six degrees of freedom (df) relative to individual tooth Cartesian coordinate systems.

Main Results:

• Tooth displacements were reliably quantified in six df for each activation.
• Transversal-to-sagittal movement ratios varied from 2:1 to 7:1 based on activation type.
• Asymmetrical arch forms induced midline shifts and altered lateral overjet; reversed curve of Spee caused significant incisor intrusion and molar extrusion.

Conclusions:

• The developed digital typodont system shows significant promise as an advanced pre-clinical teaching and research tool.
• Observed 3D tooth movements highlight the complex consequences of orthodontic activations.
• Findings underscore the importance of considering multi-dimensional effects in orthodontic treatment planning.