The interaction of the 8962 (reconciliation of the Premium Tax Credit) , the self-employed health insurance deduction, and the self-employed SEP, Simple, and qualified plans deduction is, frankly, obscure. Increasing one entry may unpredictably decrease another entry, and you can't understand why until you work through the worksheets beginning on page 59 in IRS Pub 974.

When you made this change, did the Premium Tax Credit change? Look at Schedule 2, line 2 or Schedule 3, line 9.

To do this by hand, you would need to have all your numbers on your 8962, all your Schedule Cs, the entries on Schedule 1, your K-1(s), and perhaps other numbers as specified in the worksheets at the end of Pub 974. 

To decipher this, you would need to print your return first one way and then to other to compare them, in order to see what else changed (because something did, even if it was on a worksheet).

Thanks for this informative response. To answer your question: Yes, when I made the change, my net premium tax credit changed. But the apparent reason is simply that my income had increased (after I added the dental premiums), and I therefore qualified for a lower PTC.