The current process for making custom trays requires much time-consuming manual labor. From mold making to part cleanup, there are many steps involved. Our client wished to leverage 3D printing and scanning to streamline the process. Therefore, we needed to divide the solution into two parts, manufacturing and design automation.
The software package we created outputs 3D-print-ready STL files that could be immediately printed using biocompatible dental resins. Each tray is embedded with a unique identifier to make order tracking and logistics easy.
While we had done facial landmark detection when working for Metamason, teeth identification and landmarking were proving to be much more difficult. After trial and error, we eventually converged on a solution that had excellent repeatability. Many of the scans we used have crooked teeth, general misalignment, and even missing teeth, but the identification can converge on a correct solution.
On a high level, teeth identification is an iterative process. Its basic steps are...
- Plot an initial estimation point for each tooth
- Search a given radius around each estimated location and approximate a new position
- Cross-reference with each tooth's neighbor to check for inaccuracies
- Repeat the process using newly refined estimation points
Once the teeth had been properly landmarked, we could then start the process of generating the dental tray. We created a custom UI to give dentists the ability to batch process a collection of scans and have the ability to tweak settings.