In the last week I've been going through the GNU Health project and to my disappointment there is nothing about dentistry in the project. Somehow not really a surprise because as a dentist I often feel we're a bit of a fringe in medicine as well.
Myself I'd better stick to dentistry than start programming, but I looked around and I found a Scottish dentist who has written an Open Source dental application in Python with a PostgreSQL database, just like the GNU health project. It is called Open Molar, and you can find it here: https://openmolar.com/
As I'm a programming noob I can't judge at all if there is any easy way of merging or adding (as a plug-in) this to your existing software. Perhaps even adopt the project as the dentist in question didn't get a lot of users and kinda gave up on the project.
If possible though, it would be a nice addition to your project and perhaps a stimulus to further develop the software and / or to move to a more integrated way that dentistry is represented in the project.
Hopefully this is useful suggestion.
Daniel S. Joffe DDS