Letters to the editor

Fallacies about ceramic veneers

The amusing image of Professor Burke ‘eating his hat’ in the January issue¹ and his elegantly chosen words about porcelain laminate veneers reminded me that I was partly responsible for the erroneous belief that ceramic veneers were an American invention.

A number of people in the USA claimed that distinction including Simonsen and Calamia,² Calamia³ and Horn.⁴ In the mid 1980s, one enterprising US company claimed that they had a patent for ‘Chameleon Veneers' as well as their associated luting products. Their patent lawyers demanded royalties from UK dentists to use ‘their’ technique and claimed that all dentists had to use a ‘Chameleon certified’ laboratory for the manufacture of any ceramic veneers. Most people ignored them, but I had forgotten ‘why’ until I wrote an article in 2011 called ‘Porcelain pornography’,⁵ which criticized extensive elective tooth destruction as being an abuse of the original conservative ceramic veneer concept, and denouncing what I regarded as their now widespread over-prescription for minor aesthetic problems. In that article's references, I attributed their invention to Calamia³ and to Horn.⁴

That FDJ publication provoked a mixed response from Professor Richard Simonsen, then in Kuwait, who agreed enthusiastically with my criticisms about inappropriate sound tooth destruction for veneers, but stated that etching of ceramic was originally his idea and that both Calamia and Horn were NYU postgraduate students working in his laboratory at that time. Unfortunately, the Simonsen and Calamia IADR abstract (published in J Dent Res) that he sent me as proof mistakenly described the use of hydrochloric acid, rather than hydrofluoric acid, for etching ceramic – something which it would not do.²

I then vaguely remembered an old letter in the BDJ from a person named ?MacCulloch? After making some enquiries in Cork, I wrote to Professor MacCulloch, who had retired to live in Cyprus, to introduce myself and to enquire about a ‘possible letter in the BDJ by him that I had vaguely remembered reading many years previously’. By return of post, I received a photocopy of that highly detailed 1987 BDJ letter,⁷ including his UK and US patent numbers, giving the full history, and thereby exploding the myth that ceramic veneers were originally an American idea.^6,7 Accompanying that photocopy was a beautifully handwritten letter (which I still have and treasure) because it started with the immortal words:

‘Dear Martin,

The greatest thief of original ideas and patents is the good American citizen and the ‘latest thing from America is seldom born in the USA’…’

The real truth, therefore, as proven in that BDJ letter and another BDJ article,^6,7 is that the development of etching of ceramics for use in dentistry goes back to the 1960s and was largely based on the work of Professor William MacCulloch, a Scotsman, who was head of Prosthetic Dentistry in University College Cork, Ireland. ‘Bill’ had completed his MSc project on etching ceramics in Manchester from 1966 to 1967 and it is published there.⁸ He applied for various patents in the UK and USA.

His 1968 BDJ article was illustrated by photographs of a set of conservative anterior ceramic veneers, dated and certified on 1st March 1967, by the Department of Medical Illustration of the Manchester Royal Infirmary.⁶

In 1987, in his letter to the editor of the BDJ, entitled ‘US patent problems’, Bill MacCulloch rejected outright the claims of the validity of USA patents for ceramic veneers (mainly because they were not original) and urged dentists to resist any company's demands for royalties for their use.⁷ He wrote:

‘I also claim that the fabrication of pre-formed or custom ceramic was described, illustrated and implicit in the publication in the article in the BDJ in 1968 and also in my MSc thesis in 1967. For my part, therefore, I am quite willing that any of my colleagues should use the procedures on castable ceramics and on anterior veneers based on the research which I performed in Manchester University from 1966–1968 without having to consider royalties. If any of my other colleagues, or their legal advisors, choose to challenge my inventions as not being the original, I invite them to prove prior claims antedating mine in 1967. I am quite convinced they cannot, and the onus is on them to prove the originality of their patents, especially if they wish to impose any industrial restrictions.’

I assured Bill that I would put my errors in attribution right and, hopefully, ensure that the development of etching for conservative ceramic veneers was now credited correctly to him … and hence this letter to this editor.

So, eat your hat, Americanos…