Aim:

To evaluate the compliance of websites promoting proprietary orthodontic appliances available in the UK against advertising standards outlined by the Advertising Standards Authority Committee of Advertising Practice (ASA CAP) Code.

Design:

Cross-sectional study.

Setting:

Websites promoting proprietary orthodontic appliances available in the UK, including fixed, removable and aligner systems sold as a complete system under a brand name.

Methods:

A comprehensive, systematic approach was adopted, beginning with a 2020 scoping search on Google and social media platforms (Instagram and Facebook) to identify keywords. Keyword searches were conducted on Google in 2020, 2023 and 2025 to identify relevant websites. To ensure contemporary relevance, only websites identified in the final 2025 search were included for analysis. Raters underwent training and calibration before independently evaluating websites for compliance with advertising standards using bespoke judgement criteria derived from the ASA CAP Code, across four domains: comprehensiveness of treatment information; presentation of treatment information; objectivity of treatment information; and substantiation of claims. Discrepancies were resolved through group discussion to determine agreed scores. Data were analysed using descriptive and inferential statistics (Fleiss’ kappa and Kruskal–Wallis tests).

Results:

The 2025 search identified 970 websites, of which 39 met the inclusion criteria. Inter-rater reliability showed almost perfect agreement (kappa >0.9). Compliance varied significantly across domains: 45% of all claims provided comprehensive information, 54% had clear presentation, 38% maintained objectivity and only 4% of claims were substantiated with evidence. Nearly all websites (95%) omitted common risks and 92% failed to mention alternative treatments. Direct-to-consumer and tele-dentistry websites showed poorer compliance than dentist-delivered systems.

Conclusions:

Orthodontic appliance websites showed poor compliance with ASA CAP Code standards. The majority used descriptive language and words in place of numbers to quantify magnitude, alongside subjective content and unsubstantiated claims, with omissions of treatment risks. These findings raise significant concerns about online orthodontic advertising and its potential impact on informed patient decision-making.

Plain language summary

How well do UK websites for orthodontic appliances follow advertising rules?

Why was the study done? Orthodontic appliances, like braces and aligners, are increasingly marketed online in the UK, but it is unclear whether these websites follow advertising rules. The Advertising Standards Authority (ASA) has set guidelines to ensure ads are honest and clear. This study looked at whether orthodontic websites are meeting these standards to protect consumers. What did the researchers do? The research team examined 39 UK-based orthodontic websites that promote braces and aligners. They checked these websites for compliance with the ASA’s advertising rules, which focus on the treatment information provided to be clear, accurate, and evidence based. They also assessed whether important information about common treatment risks, side effects, contraindications and alternate treatments was included. What did the researchers find? The study revealed several issues with the advertising on orthodontic appliance websites. Overall, only 45% of websites provided comprehensive treatment information. More than half (54%) presented clear information, but many used vague language like ‘fast’ or ‘painless’ without clarity. All websites (39/39) included patient and/or dentist testimonials to promote the appliance, and only 4% of claims were backed by evidence. Websites for dentist-delivered aligners performed better in meeting standards and were the only appliance to include some (9%) substantiated claims. Direct-to-consumer aligners and tele-dentistry sites had more unsubstantiated claims and missing information. What do the findings mean? This study highlights the need for better advertising practices by websites of orthodontic appliances. It shows that many websites fail to provide reliable and evidence-based information, which could mislead consumers. Improved transparency and adherence to advertising standards are necessary to help people make informed choices about orthodontic treatments.