Minimal cavity design

I read your editorial entitled ‘The genesis of minimal cavity design’¹ with great interest. I concur with your views that Richard Elderton's work, taking a fresh look at cavity design, was ‘20 years ahead of its time’ and the need to investigate the merits of new concepts by means of high-quality clinical trials, prior to promoting the concepts as best practice.

Notwithstanding your ‘reservations with regard to whether the narrow isthmus and occlusal design (as and when occlusal preparation rather than fissure sealing may be indicated) would actually work with amalgam’, a study published in 1992 revealed a much more significant problem – the difficulty of adapting and condensing amalgam in the rounded (raindrop-shaped), limited occlusal access proximal portions of cavities of the type advocated by Elderton, even when condensation instrumentation of modified (rounded) design was used.² The outcome of this work, albeit a small study, precluded an ethical approval application to conduct a randomized controlled trial to compare the use and performance of amalgam and composite in the restoration of Class II cavities of conservative design, ie the sort of study you indicate remains to be conducted.