Skip to content
View commentaries on this research

Please note that this summary was posted more than 5 years ago. More recent research findings may have been published.

This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

This review found that new surface and shallow dental procedures, called micro-invasive treatments, reduce tooth decay by about three quarters. The treatments for adults were applied to the surfaces of teeth that touch or are next to each other. Four types of treatment were compared with non-invasive strategies such as advice on flossing or the application of fluoride varnish. There were too few trials to determine which micro-invasive technique is best, or for which groups of patients it was most suitable. This may limit the implementation of this promising approach into UK practice.

Why was this study needed?

Dental caries (tooth decay) represents an important preventable disease. Dental programmes for prevention are well developed in Scotland; where despite a steady improvement since the 1980s, more than a quarter of children overall have obvious decay. The greatest burden occurs in those from disadvantaged backgrounds. While oral health in England has improved significantly across the population too, marked inequalities do persist here also. In the 30 years up to 2009 one report shows that the proportion of adults in England without any natural teeth fell from 28% to 6%. However, people from managerial and professional occupation households had better oral health (91%) compared with people from routine and manual occupation households (79%).

Decay on adjacent tooth surfaces is common and is prevented by flossing. It is important to manage the early stages of decay before a cavity is formed and two methods are currently used. The first one is invasive and involves drilling and inserting a filling. The second method involves non-invasive strategies such as flossing or application of a fluoride varnish.

This systematic review aimed to examine a third approach using micro-invasive treatments. These treatments involve preparing the tooth surface using an acid and then applying a sealant or resin to protect the teeth from further decay. The researchers looked to see if these treatments might reduce the loss of dental hard tissue and the need for more invasive treatments in the future.

What did this study do?

This was a Cochrane systematic review that identified eight randomised controlled trials from Europe, Asia and South America including 365 children and adults. None were from the UK. All trials involved trying out the treatments on different teeth in the same person. All studies compared micro-invasive treatments to a range of non-invasive strategies such as dental hygiene advice on flossing or fluoride varnish in adults. Follow up ranged from one to three years. In seven of the eight trials the participants and the dental personnel were aware of the treatments that were used. These trials were assessed to be of high risk of bias. Four trials had received industry funding to conduct the research. The review followed standard systematic review methods and included a meta-analysis to pool the data from individual trials.

What did it find?

The researchers found seven trials and included 602 teeth in the analysis. They pooled data on the most sensitive measure of caries progression.

  • Micro-invasive treatment significantly reduced the odds of caries progression by 76% compared with non-invasive strategies or no treatment (odds ratio 0.24, 95% confidence interval 0.14 to 0.41).
  • No adverse events after the micro-invasive treatment were identified by the four studies that measured adverse outcomes.
  • It was not possible to establish which micro-invasive method worked better than the others due to the small number of trials.

What does current guidance say on this issue?

The 2014 guidelines of the Scottish Intercollegiate Guidelines Network on dental interventions to prevent caries in children did not include recommendations about any micro-invasive interventions. It does recommend fluoride varnish applied at least twice yearly in all children and the use of resin based sealants to permanent teeth.

NICE guidance on oral health for local authorities and partners published in 2014 suggests that amongst other things, an oral health needs assessment in performed and a strategy developed. This they say should set out how the local authority and its health and wellbeing commissioning partners will address the oral health needs of the local population as a whole and those groups at high risk of poor oral health. Minimally invasive procedure might be part of this strategy.

What are the implications?

The researchers acknowledge that although the overall treatment effect in these trials was large the quality of evidence was moderate. This was partly because the studies were of short duration. There was also a lack of blinding – staff carrying out procedures and measuring impact would have known which treatment was given. But objective measurements such as X-rays were used, so potential bias of this sort would not have made a large difference to the results. There was insufficient evidence to determine the benefits of different micro-invasive techniques. The size of this problem in the UK is large and so further testing of these micro-invasive treatments is likely in UK practice. For now it is not known if and how this new intervention will be taken up by dentists or other dental professionals. Training in its use will need to be considered.

Citation and Funding

Dorri M, Dunne SM, Walsh T, et al. Micro-invasive interventions for managing proximal dental decay in primary and permanent teeth. Cochrane Database Syst Rev. 2015;(11):CD010431.

No funding information was provided for this study.


NICE. Oral health: local authorities and partners. PH55. London: National Institute for Health and Care Excellence; 2014.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

NIHR Evidence is covered by the creative commons, CC-BY licence. Written content and infographics may be freely reproduced provided that suitable acknowledgement is made. Note, this license excludes comments and images made by third parties, audiovisual content, and linked content on other websites.

  • Share via:
  • Print article


The micro-invasive treatment  involve preparing the tooth surface with an acid and then either placing a sealing cover on top of the surface or ’infiltrating’ the softer demineralised tissue with resins. These newer methods work by installing a barrier either on the tooth surface or within the softer tissue to protect it against acids and avoid the further loss of minerals from within the tooth. This, in theory, should stop the decay.

This approach can be performed by a dentist or other dental practitioner and involves the loss of a few micrometres of tooth tissue because of the need to condition the tooth surface with acid.

The treatments studied in this review covered a variety of different substances and techniques. These included the use of different strengths of acid for removing the affected area of the tooth. This area was then treated with resin infiltration, resin sealant, sealant patch or glass ionomer.


Back to top