Upper Tribunal rules Invisalign aligners are not dental prostheses in HMRC v Align Technology

The Upper Tribunal has ruled that Invisalign clear aligners do not qualify as "dental prostheses" for VAT purposes, overturning a First-tier Tribunal decision and confirming that their supply is chargeable at the standard rate. The decision of Mr Justice Edwin Johnson and Judge Jeanette Zaman in HMRC v Align Technology Switzerland GmbH, released on 7 July 2026, turns on the meaning of a term left undefined in the legislation.

Align had treated its aligners, bespoke removable orthodontic appliances that reposition the teeth to correct malocclusion, as exempt supplies of dental prostheses within Items 2 and 2A of Group 7 of Schedule 9 to the Value Added Tax Act 1994, which implement Article 132(1)(e) of the Principal VAT Directive. HMRC assessed them as standard-rated. The First-tier Tribunal accepted Align's construction; HMRC appealed on the single ground that the term had been misinterpreted.

A question of law, not fact

A threshold dispute concerned the nature of the appeal. Relying on the Court of Appeal in A Taxpayer, Align argued that the meaning of an ordinary English expression is a question of fact, so that the tribunal could intervene only if the First-tier Tribunal had reached a conclusion no reasonable body could reach. The Upper Tribunal disagreed. Unlike A Taxpayer, where there was no dispute about the meaning of "exceptional" and only whether the facts met it, this was a definitional dispute in which the parties advanced rival constructions of "dental prostheses". That made it a question of statutory construction, and therefore a question of law, which the tribunal was free to decide for itself without applying the Edwards v Bairstow threshold.

The meaning of a prosthesis

Approaching the construction, the tribunal accepted that exemptions must be interpreted strictly, though not so as to deprive them of effect, and that the purpose of the exemption is to prevent health-related products from becoming inaccessible through the addition of VAT. Purpose and context could not, however, enlarge the wording beyond the items actually listed.

Drawing on a range of dictionary definitions and on Perry v Adjudication Officer, in which a colostomy bag was held not to be a prosthesis, and Carden v Pickerings, concerning surgical plates and pins, the tribunal concluded that a prosthesis is an artificial replacement for a missing or malfunctioning body part which performs or assists the relevant bodily function. It does not extend to something external that merely provides support or operates as a course of corrective treatment. The addition of "dental" confined that concept to the teeth rather than widening it, so that a dental prosthesis is a device replacing missing or broken teeth. On the First-tier Tribunal's own unchallenged findings, the aligners replaced no teeth and so fell outside the term.

The tribunal found modest support in guidance from the EU VAT Committee. Its guidelines recorded the almost unanimous view, held by 24 to 27 of 29 member states, that the exemption does not reach "dental devices", and the accompanying working paper, which the tribunal held admissible as an aid to interpretation, explained that a brace is an aliud, another thing, distinct from a prosthesis. Aligners perform a comparable function to braces. Given limited but real weight, that material reinforced the tribunal's own construction.

The appeal was allowed. The tribunal set aside the decision below and remade it to dismiss Align's appeal, so that the aligners are chargeable to VAT.