Orthodontist tax services: the GST/HST split most practices leave on the table

The DPC T2, filed the same way, for a different kind of practice

Orthodontists incorporate under the same Dentistry Professional Corporation framework as any RCDSO member, so the corporate math starts identically: roughly 12.2% Ontario tax on the first $500,000 of active practice income, as at the time of writing, with the balance owing three months after year-end for most DPCs claiming the small business deduction. What differs is the income itself — a handful of large, multi-year contracts rather than daily fee-for-service production — which changes how we build the T2 filing calendar around your new-case cycle and how carefully we track adjusted aggregate investment income once retained earnings start generating passive returns above the $50,000 threshold that begins grinding down the federal small business limit.

GST/HST: where orthodontics genuinely differs from general dentistry

Most clinical dentistry is a simple exempt supply: no GST/HST charged, none recovered. Orthodontics has an extra layer. Orthodontic appliances — the braces, aligners, and retainers themselves — are zero-rated medical devices, and CRA has long accepted an administrative arrangement letting practices treat a defined portion of each case fee as the appliance supply rather than folding the whole contract into the exempt professional-services bucket.

The payoff is real: input tax credits on the HST paid for aligner and lab costs attributable to the appliance portion, something a general dentist billing a fully exempt case fee cannot claim on the equivalent expense. See the difference between zero-rated and exempt supplies for the mechanics behind why this split matters. The catch is documentation — the split has to be defined consistently in the fee schedule and applied the same way case after case, because an allocation invented after the fact does not survive a review. We set the allocation up once, at the chart-of-accounts and invoicing level, so every case follows it automatically.

When is the case fee actually earned?

A multi-year treatment contract raises a genuine income-timing question: the fee is often billed, in full, at the start of the case, while the clinical work is delivered over the following one to three years. Tax law generally does not let a business defer income simply by leaving cash uncollected, but it also does not require tax on the portion of a fee that relates to services you have not yet performed — a reserve is generally available for the unearned share of an amount received or receivable for work still to come, provided it's computed and supported consistently at each year-end.

This is separate from the older work-in-progress rules that used to let designated professionals, dentists included, elect out of taxing unbilled time entirely — an election the 2017 federal budget phased out. Whichever mechanism applies to your billing pattern, the practical answer is the same: we align the T2's revenue timing with the same treatment-based schedule your bookkeeping already tracks, covered in more depth on our orthodontist bookkeeping page, so the corporation is never taxed materially ahead of, or behind, the work actually done.

Equipment and imaging: CCA on the tools of the specialty

Cephalometric and panoramic imaging units, intraoral scanners used for digital impressions, and the computers running your imaging software fall into the standard equipment classes — most clinical hardware in Class 8 at 20% declining balance, computers and imaging software in Class 50 at 55%. The $1.5 million immediate expensing measure closed for property available for use after 2023, but the accelerated investment incentive still suspends the half-year rule for eligible purchases available for use before 2028, roughly doubling the usual first-year claim. Because most of the practice's revenue is either exempt or zero-rated rather than fully taxable, the HST on new equipment is only partly recoverable as an input tax credit, so we plan large purchases with that blended recovery rate in mind rather than assuming a clean claim. If your practice or your own training history runs through the US, the corporate side of that picture is covered on our cross-border tax page for orthodontists.

Source: CRA — GST/HST for businesses.