Maintain a price list per dentist
Every dentist has a price list, even if you do not write it down. Make it explicit. The right price should appear automatically on the invoice.
Invoice from completed cases
The case record already contains work type, materials, and shade. Generate the invoice from it instead of retyping.
Group by month and by dentist
Most dentists prefer one monthly invoice over many small ones. Software should let you batch them.
Track invoice status
Draft, sent, paid, overdue. Without these statuses you will chase the same payment twice.
Export for the accountant
The accountant should not be a manual translator. Export financial reports straight from the system.
See Dental Lab Guru's invoicing module for a worked example.