Tooth decay is very common and can cause pain, eating and speaking difficulties, and self‐consciousness. Teeth are made up of three layers: enamel (hard outer layer), dentine (hard inner layer), and pulp (nerves and blood vessels). Our mouths contain bacteria, which grow in a sticky film over our teeth known as dental plaque. The bacteria live on sugar from our diet and turn it into acid that dissolves the teeth. Saliva can reverse this process, but if there is too much sugar in the diet or bacteria are not removed often enough by toothbrushing then the acids will erode the teeth. This can progress into the dentine, eventually causing a hole in the tooth, which is known as a cavitated carious lesion. If it reaches the pulp, it can cause infection. Cavitated carious lesions can be treated by complete removal of decayed parts of the tooth and placement of a filling. Dentists call this non‐selective carious tissue removal and conventional restoration. Although effective, this risks weakening the tooth or causing problems if the pulp of the tooth is exposed. There are some newer ways of treating the tooth which involve removing less or none of the tooth decay.
What was the research?
A systematic review of the evidence to find out the best way for dentists to manage decay that has extended into dentine.
Who conducted the research?
The research was conducted by a team led by Falk Schwendicke from Charité – Universitätsmedizin Berlin, Berlin, Germany, on behalf of Cochrane Oral Health. Tanya Walsh, Thomas Lamont, Waraf Al-yaseen, Lars Bjørndal, Janet E. Clarkson, Margherita Fontana, Jesus Gomez Rossi, Gerd Göstemeyer, Colin Levey, Anne Müller, David Ricketts, Mark Robertson, Ruth M. Santamaria and Nicola P.T. Innes were also on the team.
What evidence was included in the review?
Data was extracted from 27 randomised controlled trials. A total of 3350 participants (4195 teeth) participated in the trials, most of the participants were children. Treatment success or failure was usually tested 12 to 24 months after treatment.
What did the evidence say?
The following treatments were tested in the studies:
- Selective carious tissue removal (or selective excavation): tooth decay around the edges of the cavity is fully removed, but some softened dentine is left close to the tooth pulp. A filling is then put in.
- Stepwise carious tissue removal: most of the decayed parts of the tooth are removed, but soft dentine is left in areas close to the pulp and the cavity is filled using materials such as composite. After a gap of several months, more of the softened dentine is removed.
- Sealing carious lesions using sealant materials: a thin coating made from resin or glass ionomer is painted over the decayed tooth, hardens in a few minutes and stops the bacteria from reaching the tooth decay.
- Sealing using preformed metal crowns, also known as the Hall Technique: a preformed metal crown (i.e. chosen from a selection of sizes to closely fit the tooth, but not moulded for the particular tooth) is pushed over the decayed tooth to seal in the decay.
- Non‐restorative cavity control (NRCC): cavities are made easier to clean, and patients are helped to develop good tooth care and eating habits to reduce the risk of the decay progressing.
For decayed baby (primary) teeth, putting an off‐the‐shelf metal crown over the tooth or only partially removing decay before placing a filling may be better than the conventional treatment of removing all decay before filling.
For decayed adult (permanent) teeth, partial removal of decay before filling the tooth, or adding a second stage to this treatment where more decay is removed after several months, may be better than conventional treatment.
How good was the evidence?
Most studies did not involve many people, and most people had no problems with their fillings regardless of which treatment they received. All studies were at high risk of being biased in some way. Currently, we only have low to very low certainty in most findings. This means future research could lead to different conclusions.
What are the implications for dentists and the general public?
Compared with conventional restoration, the Hall Technique and selective carious tissue excavation have a lower risk of failure in baby teeth. Selective carious tissue excavation and stepwise carious tissue removal have a lower risk of failure in adult teeth. Most studies showed high risk of bias and limited robustness, resulting in low‐ or very low‐certainty evidence for most comparisons.
What should researchers look at in the future?
There is a need for more research investigating direct comparisons of interventions included in this review. Given the moves towards treatments that are less invasive being supported by the findings of this review, it would be helpful for future studies to focus on comparisons of those less‐invasive treatment options in comparisons rather than against conventional restoration.
Schwendicke F, Walsh T, Lamont T, Al-yaseen W, Bjørndal L, Clarkson JE, Fontana M, Gomez Rossi J, Göstemeyer G, Levey C, Müller A, Ricketts D, Robertson M, Santamaria RM, Innes NPT. Interventions for treating cavitated or dentine carious lesions. Cochrane Database of Systematic Reviews 2021, Issue 7. Art. No.: CD013039. DOI: 10.1002/14651858.CD013039.pub2.
This post is an extended version of the review’s plain language summary, compiled by Anne Littlewood at the Cochrane Oral Health Group Editorial Base.