Hi Len, you may have missed the acquisitions, see below timings and also the total price paid of $6.6M+ as detailed in the full year accounts.
24th July 2018 - Noosa practice acquisition
12th March 2019 - 2 practices in Springfield Lakes and Maroochydore
4th April 2019 - Single practice in Strathpine
10th December 2019 - 2 practices Gatton and Laidley (not included in FY financials since in this FY)
So no they have not borrowed to pay dividends, the company has maintained its stated 60-80% payout ratio, and taken on minuscule amounts of debt to acquire various dental practices. Note debt at end of last financial year was $9.2M on profit before tax of $10.8M or profit after tax of $7.8M, so the debt covenants are more than covered and the companies debt is only equal to 1 year of PBT - which is very small for a company with $120M market cap.
What you could question though is the success of ONT's grow by acquisition business model, which personally I believe can be an excellent investment IF you purchase with a considerable enough income from dividends. I don't hold ONT, but have thought I may get a good entry during the Covid lockdowns, hasn't played out yet... But it could as I would expect SSS to be down significantly in Q4 and possibly Q1 21.