There is growing evidence supporting the use of more conservative techniques to treat carious primary and permanent teeth. Current caries management for deep lesions includes a variety of approaches; two-step caries removal (stepwise excavation), where incomplete caries removal is carried out at the first appointment then at the second visit the remaining caries is removed to give complete caries removal, then sealing; one-step caries excavation, where incomplete caries removal is followed immediately by placement of a definitive restoration (partial caries removal); and techniques that involve no caries removal and sealing.1

So far, studies looking at incomplete caries removal have shown advantages for the more conservative caries removal techniques to treat deep, cavitated carious lesions over complete caries removal.1,2 The main advantages are the significant reduction of pulp exposure accompanied by no detriment to the tooth in terms of pulpal symptoms.

This study by Franzon et al. overall reinforces previous studies' findings, comparing the two-year clinical and radiographic outcomes of one-step partial caries removal (PCR) and total caries removal (TCR) performed in primary molars with deep caries ‘inner quarter of dentine assessed radiographically’ of three to eight year olds. The mean incidence of pulp exposure was significantly lower in PCR (2%) than TCR (27.5%; p<0.01). Clinically, overall the majority of treated teeth (94%), independent of the treatment performed, showed no failures after one year. By comparing the success rates among the two treatment groups no statistical benefit of one approach over another was observed (p=0.34), even when treatments in multisurface lesions were compared to occlusal lesions (p=0.08).

The methodology of this RCT is acceptable. The main limitation of this study is around the subjective criteria assessing how much carious tissue was removed. Although the authors state that PCR was carried out to maintain much of the decayed tissue, excavation was stopped when a ‘leathery’ consistence was observed. This leads us to assume that most of the infected tissue was removed leaving only a thin layer of infected dentine above the pulp. By this criterion, it is possible that caries was completely removed in some areas of the pulpal wall creating a pulp exposure even in the partial caries removal group where the aim of the treatment is to avoid this.

An unrestricted allocation was carried out; however, it was not clear who allocated treatments or if allocation was at treatment time, a possible source of selection bias in this study. On the other hand, the use of standardised clinical procedures including local anaesthetic, rubber dam and identical filling materials (composite) across both arms for clinical procedures, increased the quality of the study and reduced the risk of performance bias. Patients and examiners were masked to the intervention; however, masking of operators (as with most dental procedures) was not possible.

Despite increasing numbers of clinical trials looking at comparisons between incomplete/no caries removal, there is still no agreement amongst researchers as to what constitutes partial caries removal (there were still pulp exposures in the PCR arm) and so how do we translate these findings to clinical practice? Exactly how much caries should be left to avoid pulp exposures and still achieve the best long-term outcomes for our patients? Issues around terminology and standardisation of interventions need to be addressed. Having said that, although there is some risk of bias, this study adds to the growing picture of evidence that in asymptomatic primary teeth with deep caries, PCR reduces the incidence of pulp exposure and is not harmful compared to TCR. It is also a more efficient use of operative time. These findings support PCR as a clinical and time-effective technique in the management of dentinal carious lesions in primary molars.

Practice point

  • Dental practitioners should consider the use of more conservative techniques like partial caries excavation over total caries excavation for patients presenting with, symptomless, deep carious primary teeth, as it reduces pulp exposure and it does not have any harmful effect on the teeth

  • The use of partial caries removal reduces significantly the operative time during treatment of deep carious lesions. This could be advantageous for treatment of paediatric patients.