Sir, we were interested to read the article on consent and capacity1 which gave a helpful insight into the implications of the Mental Capacity Act for special care dentistry. However, we would like to clarify several points within the article which may have caused confusion for readers.

The suggestion that implied consent for both examination and treatment, which happens when patients sit in a dental chair and voluntarily open their mouth, is acceptable, is not correct. Consent to a dental examination can be implied in this circumstance, but expressed, informed consent is required for all treatment, including the taking of radiographs. The quality of the explanations and information given to (and understood by) the patient are crucial to obtaining informed consent.

In addition, while the DDU would agree that a patient's signature on a consent form may help to confirm that consent has been obtained, it cannot be relied upon on its own, as suggested in the article. A patient's signature on a treatment plan or consent form is in our experience of secondary significance to the notes made in the clinical records of conversations where the patient is given explanations and warnings, particularly concerning treatment options and potential complications.

In some cases a patient's condition may change between the initial consultation and the time at which treatment takes place, which can affect the nature of treatment and its likely risks and chances of success. In such cases the dental professional will need to explain the changes and to obtain consent again. Re-confirmation of consent immediately before treatment is always prudent, as of course is making a record of this.

If the treatment is complex, has particular risks, or several treatment options are available and have been discussed, then the DDU recommends that this is noted into the patient's records. If an allegation of lack of consent is made, entries in clinical records are more valuable from an evidential standpoint than a signature on a consent form. The DDU does not, however, discourage the use of consent forms, written treatment plans and explanatory leaflets.

Finally, while the article is mainly about adults without capacity, the authors state that 'informed consent is required from all patients or, in the case of children, parents'. However, children under 16 can consent to treatment if they understand its nature, purpose and hazards following review by the House of Lords in the 1985 Gillick judgement.

To be able to consent, the child must understand the nature of the proposed treatment and fully understand and appreciate the consequences of the treatment, the alternatives and the failure to treat. It is only where a child is not Gillick competent, that whoever has parental responsibility may give authority to treat under the Children Act 1989.