Dental lab cross-border tax: US materials, US work, and shipping to US dentists

Materials and equipment bought in the US: duty, GST and CARM

Zirconia and PMMA disks, casting alloys, mills, 3D printers and sintering furnaces routinely come from US manufacturers. Bought through a Canadian distributor, a tariff simply shows up as a higher invoice; order directly from a US supplier and you become the importer of record, which means an account in CBSA’s CARM portal and your own financial security for duties. Duty and any surtax become part of the landed cost of that disk of zirconia or that mill, and the GST charged at the border on the duty-paid value is recoverable as an input tax credit like any other. USD invoices are booked at the exchange rate on the invoice date and settled at the rate on the payment date, with the difference posted as a gain or loss — see how to record USD transactions in Canadian books for the routine we apply to every US supplier account. A financed mill or printer follows the same logic over a longer horizon: the USD loan or lease balance is revalued at each reporting date, and the resulting gain or loss sits apart from operating income so a currency swing on the equipment loan does not get mistaken for a change in the lab’s actual production margin.

Work crossing the border in either direction

Cases move both ways, and each direction has its own mechanics. A useful reassurance for either direction: buying or selling a finished appliance is a sale of goods, not a services engagement, so the permanent-establishment questions that follow a Canadian business sending staff or equipment into the US generally do not arise here — nobody from the lab is working on US soil, and no US business location is being created by mailing a crown across the border.

Selling to US dentists: zero-rated here, someone else’s rules there

On the Canadian side, a finished appliance shipped to a US dental office is an export of goods: it is zero-rated for GST/HST, same as any other export, provided shipping records and the underlying prescription are kept on file. The US side is a different rulebook. Many states exempt prescription medical and dental devices from sales tax, but the rules and the paperwork to claim the exemption differ state by state, so we check the destination state rather than assume Ontario’s zero-rating carries across the border. Regulatory registration is the other piece: a lab manufacturing devices for the US market generally falls under FDA establishment registration and device listing, though a genuinely custom, patient-specific appliance made to an individual dentist’s order can qualify for the FDA’s custom-device exemption. That exemption is capped at a small number of units per device type per year, so a lab shipping into the US on a growing, regular basis should not assume it still applies once volume increases, and should have that confirmed before scaling rather than after.

Logistics deserve a mention alongside the compliance questions. Most cases move by courier as low-value parcels, which usually clear under simplified procedures on the US side rather than a formal customs entry — but a delayed shipment lands on a dentist’s chairside schedule, not just a spreadsheet, so we build extra turnaround slack into the first several shipments on any new US account until the pattern is proven.

Sizing this file honestly

For most Ontario dental labs, this is a moderate file — heavier than a purely domestic shop because US material and equipment purchases are routine, lighter than a true cross-border services business because a straightforward sale of a physical, prescribed device does not carry the withholding and permanent-establishment questions that follow US client services. The domestic side — zero-rating, GST34 refunds, and CCA on the mill itself — is on our tax services page for dental labs, and the full cross-border toolkit for clients who need more is on our cross-border tax services page.

Source: CBSA — CARM, the CBSA Assessment and Revenue Management system.