Review of the Month: do antibiotics cause more harm than good?

AntibioticsDentists often have to remove teeth which are affected by decay or gum disease. They also remove wisdom teeth that are poorly aligned or underdeveloped. The risk of infection after extracting wisdom teeth is around 10%, but can be as high as 25% in patients who are already sick. Swelling, pain, fever and dry socket are common complications.

But should dentists try to protect patients from infection by giving them antibiotics just before or just after surgery? Or are the side effects of the antibiotics worse than the infection? There has been concern that too much exposure to antibiotics is a risk to health, as the body becomes less able to fight off infections. What’s the evidence on the use of antibiotics to prevent complications after tooth extraction? Our highlighted Review of the Month for August considers the issues.

What was the research?

A systematic review of the evidence to find out whether taking antibiotics is an effective way to prevent infections after tooth extraction.

Who conducted the research?

The research was conducted by a team led by Giovanni Lodi from the Universita degli Studi di Milano, on behalf of the Cochrane Oral Health Group. Lara Figini, Andrea Sardella, Antonio Carrassi, Massimo Del Fabbro and Susan Furness were also on the team.

What evidence was included in the review?

Data was extracted from 18 randomised controlled trials. A total of 2,456 people having teeth extracted participated in the trials, and were randomly assigned to antibiotics or placebo.

What did the evidence say?

There is evidence that antibiotics reduce the risk of infection by approximately 70%. There is also evidence that people who take antibiotics have less pain a week after the extraction compared with those who do not. However, using antibiotics caused more generally brief and minor side effects for these patients. There was no evidence of a difference between antibiotics and placebo in reduction of fever or swelling.

The review found that approximately 12 people would need to receive antibiotics in this way to prevent one infection, and 38 people would need to be treated with antibiotics to prevent one case of dry socket

The review concludes that antibiotics given to healthy people to prevent infection may cause more harm than benefit to both the individual patients and the population as a whole. There were no trials which looked at antibiotics to prevent infections in people with severely decayed teeth, or those who were sick or had low immunity. It is possible that antibiotics may be more beneficial for these patients.

How good was the evidence?

13 trials were at high risk of bias, and the risk of bias for the other five trials was not clear due to poor reporting of the methods and results. The quality of the evidence was generally moderate for most of the outcomes that were under study.

What are the implications for dentists and the general public?

There is moderate quality evidence that use of antibiotics as a prophylaxis, given to prevent infection, reduces the risk of infection in patients undergoing tooth extraction. There is no clear evidence that the timing of when the drugs are given (just before or just after surgery) is important. The size of the benefit is not enough to recommend routine use of antibiotics, due to the increased risk of mild side effects and the potential for developing resistance to antibiotics.

What should researchers look at in the future?

Future randomized controlled trials should look at whether infection can be prevented by use of antibiotics in patients at high risk of complications, such as people with low immunity. Trials on patients undergoing extractions for severe tooth decay are also needed.


Lodi G, Figini L, Sardella A, Carrassi A, Del Fabbro M, Furness S. Antibiotics to prevent complications following tooth extractions. Cochrane Database of Systematic Reviews 2012, Issue 11. Art. No.: CD003811. DOI: 10.1002/14651858.CD003811.pub2.