The origin of this systematic review is the propositions by John Tomes, in 1859, that it would be better to leave some carious tissues in a cavity in order to maintain the pulp vitality and by GV Black, in 1908, that is preferable to expose the pulp of a tooth than to leave it covered only with softened dentine.1 Since then, dentists have followed Black's approach, removing all suspicious dentine (soft, black or dark-coloured). When our clinical instructors asked, we answered, “I have removed all the caries”! It is easy to recognise when the walls of the cavity are clean, but it is harder to define what is meant by “partial”: did we remove caries just in the walls? Just in the enamel–dentin junction? Or just leave it all? The intervention (ie, caries removal) in this review is not clear as noted by the authors, who explained, “we do not know whether the amount of caries removal is relevant in terms of symptoms”.

The authors looked for the appropriate papers and included relevant research. They did not apply language restrictions in his search although it should be noted that the databases used may themselves bias in favour of English-language publications.

The authors found the methodological quality of the included papers to be “questionable”. They report the results for the pulp exposure, symptoms of pulpal inflammation and restoration survival and found no evidence from these four papers that classical caries removal is better than partial. These results must be extrapolated very carefully to the clinical setting because patients would require more visits to monitor the symptoms or in stepwise procedure.

The authors did not discuss others harms or costs of the interventions such as, for example, the use of different restorative materials or medicaments in the cavity. At the moment, just one study is registered at the website (Bjørndal L, Reit C. The CAP-1 trial: stepwise excavation versus one completed excavation in deep caries NCT00187837.>) and that just for the stepwise intervention. In terms of evidence, there is no evidence base to affirm that the entire carious lesion must be removed, but we do not know how much can we leave or which material is best suited for partial caries removal. What is clear is that the surgical management of caries is, at best, only a symptomatic treatment. Caries is driven by the biofilm at the surface of the teeth, an intangible process not amenable to surgical removal:2 this review shows how irrelevant the removal may be of tissues involved in the carious process. I welcome this review and I hope that it will avoid many unnecessary endodontic treatments of deep carious lesions.

Practice point

Partial caries removal appears preferable to complete caries removal in deep lesions to reduce the risk of carious exposure.