Sir, I must register my strong disapproval of a progressive commercial bias in what I have always assumed to be an unbiased professionally refereed science based journal. It is unacceptable to name any company associated with a clinical evaluation of all-ceramic bridges (BDJ 2008; 205: 477–482) that no doubt also pays the bills for what is purely and solely an advertising platform. I would not wish to go any further by challenging the content on scientific grounds.

I have spent a considerable amount of time over the years attempting to introduce proper standards in dentistry, so far with very little success. This article even mentions the use of a 'calibrated examiner', whatever that may mean – is it a person or perhaps a software tool? This whole area of employing CADCAM technology needs to be addressed in a fundamental manner in which the relevant standards, already in place and well known in the engineering industry, should be embraced and adapted accordingly. The frequent mention of the commercial enterprise associated with this refereed scientific article is frankly beyond the pale and devalues the credibility of the BDJ. The proper place to publish these results is in a monograph funded by the company concerned or alternatively in the advertising section of the BDJ having paid the appropriate fees.

The authors R. J. Crisp and F. J. T. Burke respond: We thank Dr Knott for his interest in our paper which followed accepted guidelines for the use of trade names in published research papers ie full company details when the product is first mentioned and if that company also happens to be the funder of the research this is clearly stated in an acknowledgement. We are sure that if the company (Renishaw plc. New Mills, Wootton-under-edge, Glos, UK) to which he is an advisor funded a three-year clinical evaluation (now extended to five-years) that company would also want their contribution acknowledged.

Surely Dr Knott is aware that the funding of research by ethical manufacturers is not unusual, and indeed could be considered to be essential, so that their products may be tested, either clinically or in the laboratory, by independent researchers and that the research is then published in the public domain. In this respect, three of the 12 research papers in one recent issue of another peer-reviewed scientific dental journal acknowledge funding from manufacturers.1,2,3

We are surprised that your correspondent is not aware of the term 'calibrated examiner'. The context of this term 'examiner' is clearly stated in the paragraph detailing the annual review of the restorations but if your correspondent is aware of a software tool that will examine restorations we would be most interested as we will all soon be redundant!

Lastly, we note that Dr Knott wrote a remarkably similar letter 4 in 2007 in response to a paper on the 3M ESPE Lava system 5 and being aware of his interest in the science of measurement (metrology) we wish him well in his endeavours.