Sir, it was with great interest and some concern that I read the recent paper authored by Innes, Stirrups and Evans et al. (BDJ 2006; 200: 451–454) concerned with the retrospective analysis of what was described in the title of the article as, 'a novel technique' for managing primary molar caries in general practice. The paper explores the use of the so-called 'Hall' technique over the period from 1988 to 2001 in 259 children aged between two and 11 years of age.

It is clear on the facts that the treatment regimen adopted by Dr Hall and provided for the 259 children over the 13 year period was, at the time of treatment provision, wholly untested by scientific analysis and was founded upon Dr Halls 'impression' that the technique was clinically effective, and indeed remains, at the date of publication, unsupported by the reported outcome of randomised clinical trials.

The use of this untried and untested restorative procedure in children raises significant questions about how Dr Hall ensured the protection of the childrens legal and ethical rights to self determination whilst providing dental care for them. Given the age of the children concerned, did Dr Hall tell the children's carers before treating the children that she was proposing treatment that was unsubstantiated by scientific evidence? Were all of the children's carers involved in a full discussion of the risks of the 'Hall' technique, and were they offered the alternative options for treatment of the children in their care, including that of the recognised and evidentially-based approach to the provision of PMCs involving caries removal?

These are matters which are at the heart of whether or not proper consent was obtained by Dr Hall in the treatment of these children. The concerns are self evident – if full information was not provided, and proper valid consent was not obtained, and documented, before treatment was given, then this paper records an egregious failure over an extended period to respect the rights of one of the most vulnerable groups in society.

Dr Dafydd Evans responds on behalf of the authors: Our response to C. Dean's letter is tempered by the knowledge that he will have been unaware of the full background to the Hall technique, due to the word limits on articles wisely imposed by editors of scientific journals.

Norna Hall initially provided conventionally fitted preformed metal crowns (PMCs) for her child patients. On moving to a general dental practice in Buckie, Scotland, she found herself faced with very high levels of dental disease (Scottish children have amongst the poorest oral health of any country in Europe). This was coupled with low levels of dental expectation from the parents. She found that missing out some of the stages associated with the conventional provision of PMCs (enforced by behavioural limitations) made restorative care more acceptable to her patients and their parents, yet did not seem to affect the outcome. To determine if this impression was valid, Norna Hall audited, in 1991, the outcomes for 111 PMCs which had been fitted for at least two years on primary molars with moderate to advanced decay.

These data confirmed the outcome as being acceptable, so she continued to offer the technique to her patients. The data were presented in a paper by the authors on a pilot trial of the technique published in 2000 in the online journal of the Scottish Dental Practice Based Research Network. This paper was referenced in our article, and can be readily accessed.1 With regard to obtaining valid consent before providing treatment, Norna Hall advised all parents as part of the consent process that her method of using PMCs was not widely used, but seemed to be effective. It is correct that there was no evidence from randomised controlled trials (RCTs) when Norna Hall started to use the technique (as, interestingly, there is still no evidence to date from RCTs supporting the use of the correspondent's favoured technique, that of conventionally fitted PMCs), but there was already some evidence in 1987 regarding the effect of sealing in caries in permanent teeth on its progression.2 Instead of just wringing her hands about children's rights, Norna Hall, who practised in a remote and rural area with little specialist support, actively did something to help her child patients achieve their fundamental right to oral health and freedom from dental pain. For this she has our commendation, and our respect.