Sir, your letter from J. Mew Occlusal conflict (BDJ 2009; 206: 56) worried me greatly.

The natural mandibular rest position in the majority of cases has the teeth apart, but lips together. Where there is either a short upper lip or significant skeletal base discrepancy, then the natural rest position may have the lips apart, but the teeth remain apart also.

Electro-myographic studies undertaken by Greenwood in the 1960s and Juniper in the 1970s confirms this. A fact that is generally understood and accepted, though not by Mr Mew. I note that he writes to you quite frequently and, until now, I have not been in a position to determine whether his thoughts are helpful or destructive.

The product of a tooth contact rest position is muscle fatigue, such interrupts normal proprioceptive feedback to the motor cortex. Nature's response is then to produce tooth contact in order that proprioceptive feedback is established through the teeth. However, this maintains the mechanical overload and is one of the primary causes of temporomandibular joint pain dysfunction. I cannot therefore let Mr Mew's comments pass, unaddressed, for if my colleagues follow his advice, then the incidence of temporomandibular joint pain dysfunction will inevitably increase significantly.

Surely our profession should be aiming to prevent, rather than treat, or even encourage, such a problem.