Sir, I would like the opportunity of commenting on Dr Jaspreet Virdee's interesting opinion on TMD.1 Currently there seems to be little consensus on either the cause or cure for TMD, or the most appropriate treatment. One constant feature is a retruded maxilla, but this is rarely mentioned and to my surprise many dentists are not aware of it and even specialists often seem unable to assess it.

These days dentistry is considered to be an evidence-based subject but evidence faces a problem when there are a large number of variables. It gets progressively more difficult to design studies that can consider more than five or six factors simultaneously. Each study tends to consider a number of relationships in specific situations, but many fail to establish whether the factors are causative, associated or resultant, meaning that in this situation we may be left with no more than a long list of possible factors.

In a sense the research has blighted TMD treatment rather than provide us with a set of answers. Here I believe that logic may do better than research. The condyle is a very small part of the body and yet it is blamed for many aspects of dysfunction and pain. Mammals have been around for more than 60,000,000 years and evolution has ensured that we now function quite well. In this case reason would suggest it is unlikely that more than one or maybe two things have gone wrong rather than 20 or 30 often suggested.

I am sure that many clinicians have suggestions to make, but my money is on maxillary position.