Teeth that are affected by decay or gum disease or painful wisdom teeth are often removed by dentists. Tooth extraction is a surgical procedure that leaves a wound in the mouth that can become infected. Infection can lead to swelling, pain, development of pus, fever, as well as ‘dry socket’. Dry socket is where the tooth socket is not filled by a blood clot, and there is severe pain and bad odour. These complications are unpleasant for patients and may cause difficulty with chewing, speaking, and teeth cleaning, and may even result in days off work or study. Treatment of infection is generally simple and involves drainage of the infection from the wound and patients receiving antibiotics.

Antibiotics work by killing the bacteria that cause infections, or by slowing their growth. However, some infections clear up by themselves. Taking antibiotics unnecessarily may stop them working effectively in future. This ‘antimicrobial resistance’ is a growing problem throughout the world. Antibiotics may also cause unwanted effects such as diarrhoea and nausea. Some patients may be allergic to antibiotics, and antibiotics may not mix well with other medicines. Dentists frequently give patients antibiotics at the time of the extraction as a precaution in order to prevent infection occurring in the first place. This may be unnecessary and may lead to unwanted effects.

What was the research?

A systematic review to examine whether giving antibiotics as a preventive measure reduces infection and other complications after tooth extraction. We also wanted to understand whether antibiotics work differently in healthy people compared with people with health conditions such as diabetes or HIV.

Who conducted the research?

The research was conducted by a team led by Giovanni Lodi of the Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy on behalf of Cochrane Oral Health. Lorenzo Azzi, Elena Maria Varoni, Monica Pentenero, Massimo Del Fabbro, Antonio Carrassi, Andrea Sardella and Maddalena Manfredi were also on the team.

What evidence was included in the review?

We included 23 randomised controlled trials, with 3,200 participants, who received either antibiotics (of different kinds and dosages) or placebo immediately before or just after tooth extraction, or both. Four studies were conducted in Spain, three each in Brazil, Sweden, and the UK, two in India, and one each in Colombia, Denmark, Finla