Do the drugs work? Cochrane evidence on antibiotics in dentistry

799px-Medication_amoxycillin_capsule13-17 November is World Antibiotic Awareness Week. The World Health Organization (WHO) has said that antibiotic resistance is:  “one of the biggest threats to global health, food security, and development today”. Antibiotics are used to prevent and treat bacterial infections, but if over-used they can cause bacteria to change and become resistant. This makes infections more difficult to treat, and results in longer hospital stays, higher medical costs and increased mortality (World Health Organization, 2017).

Antibiotics are still commonly used in dentistry, Cope et al (2014) estimate that 8-10% of antibiotics used in primary care are prescribed by dentists in some parts of the world. Their effectiveness has been explored by several Cochrane Oral Health reviews over the years, looking at some of the scenarios where they might be prescribed. Today we have a look back over the evidence…

Antibiotic use for severe toothache

Irreversible pulpitis occurs where the dental pulp (tissue inside the tooth which contains the nerve) has been damaged beyond repair. It is characterised by intense pain (toothache), sufficient to wake someone up at night and is considered to be one of the most frequent reasons that patients attend for emergency dental care. Any tooth may be affected, it is not restricted to particular age groups, and it usually occurs as a direct result of dental decay, a cracked tooth or trauma and thus tends to occur more frequently in older patients. The ‘standard of care’ for irreversible pulpitis – immediate removal of the pulp from the affected tooth – is now widely accepted and yet in certain parts of the world antibiotics continue to be prescribed.

A Cochrane review by Agnihotry et al (2016) found that antibiotics do not appear to significantly reduce toothache caused by irreversible pulpitis; however, only one clinical trial was found on the topic. The administration of penicillin does not significantly reduce the pain perception, or the quantity of pain medication required by people with irreversible pulpitis.

Preventing complications after tooth extraction with antibiotics

Tooth extraction is a surgical treatment to remove teeth that are affected by decay or gum disease. The other common reason for tooth extraction is to remove wisdom teeth that are poorly aligned/developed (also known as impacted wisdom teeth) or those causing pain or inflammation. The risk of infection after extracting wisdom teeth from healthy young people is about 10%; however, it may be up to 25% in patients who are already sick or have low immunity. Infectious complications include swelling, pain, pus drainage, fever, and also dry socket (this is where the tooth socket is not filled by a blood clot, and there is severe pain and bad odour). Treatment of these infections is generally simple and involves patients receiving antibiotics and drainage of infection from the wound.

A review by Lodi et al (2012) provides evidence that antibiotics administered just before and/or just after surgery reduce the risk of infection, pain, and dry socket after wisdom teeth are removed.  However, the review also found that using antibiotics causes more side effects for these patients. Additionally, there was no evidence that antibiotics prevent fever, swelling or problems with restricted mouth opening in patients who have had wisdom teeth removed. The conclusion of this review is that antibiotics given to healthy people to prevent infections, may cause more harm than benefit to both the individual patients, and the population as a whole.

Antibiotics prescribed for severe gum disease or abscesses

Dental pain is a common problem and can arise when the nerve within a tooth dies due to progressing decay or severe trauma. The tissue around the end of the root then becomes inflamed and this can lead to acute pain, which gets worse on biting. Without treatment, bacteria can infect the dead tooth and cause a dental abscess, which can lead to swelling and spreading infection that may be life threatening. The recommended treatment of this form of toothache is the removal the dead nerve and associated bacteria. This is usually done by dental extraction or root canal treatment. Antibiotics should only be prescribed when there is severe infection that has spread from the tooth. However, some dentists still routinely prescribe oral antibiotics to people with acute dental conditions that have no signs of spreading infection.

The two studies included in the review by Cope et al (2014) reported that there were no clear differences in the pain or swelling reported by participants who received oral antibiotics compared with a placebo, when provided in conjunction with the first stage of root canal treatment and painkillers. However, the studies were small. Neither study examined the effect of antibiotics delivered by themselves, without dental treatment.

Unclear evidence on the effectiveness of antibiotics to prevent bacterial endocarditis

Bacterial endocarditis (BE) is a rare disease, it is generally accepted that 10 out of 100,000 people will suffer from it each year. The infection often occurs on previously damaged or malformed areas of the heart. It is usually treated with antibiotics; however, BE is a life-threatening condition and up to 30% of people who suffer from it die, even with antibiotic treatment. It is thought that invasive dental procedures may cause BE in people who are at risk of developing it. It is not known how many cases of BE (if any) are directly caused this way. Many dental procedures cause bacteraemia, which is the presence of bacteria in the blood, and although it is usually dealt with quickly by the body’s immune system, it has been believed that bacteraemia may lead to BE in a few at risk people. Guidelines in many countries have recommended that before undergoing invasive dental procedures, people at high risk of BE should be given antibiotics in order to reduce the possibility of BE occurring. However, guidance by the National Institute for Health and Care Excellence (NICE) in England and Wales has recommended that antibiotics are not required for any interventional procedure, either dental or surgical.

The review by Glenny et al (2013) found that it was unclear whether taking antibiotics as a preventive measure before undergoing invasive dental procedures is effective or ineffective against bacterial endocarditis in people at risk. No studies were located that assessed numbers of deaths, serious adverse events requiring hospital admission, other adverse events, or cost implications of treatment.

So we can conclude that the Cochrane evidence for antibiotic use in the dental procedures explored by these reviews is not clear cut or compelling.  The general advice from the WHO is to only use antibiotics if prescribed by a healthcare professional, to follow their advice, and to finish the course of treatment. Never share your prescribed antibiotics with anyone else, and reduce the risk of infections by keeping up good levels of personal hygiene.


World Health Organization, 2017. Antibiotic resistance. Available at:, accessed 13 November 2017

Agnihotry A, Fedorowicz Z, van Zuuren EJ, Farman AG, Al-Langawi JHasan. Antibiotic use for irreversible pulpitis. Cochrane Database of Systematic Reviews 2016 , Issue 2 . Art. No.: CD004969. DOI: 10.1002/14651858.CD004969.pub4

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 .

Cope A, Francis N, Wood F, Mann MK, Chestnutt IG. Systemic antibiotics for symptomatic apical periodontitis and acute apical abscess in adults. Cochrane Database of Systematic Reviews 2014 , Issue 6 . Art. No.: CD010136. DOI: 10.1002/14651858.CD010136.pub2 .

Glenny A-M, Oliver R, Roberts GJ, Hooper L, Worthington HV. Antibiotics for the prophylaxis of bacterial endocarditis in dentistry. Cochrane Database of Systematic Reviews 2013 , Issue 10 . Art. No.: CD003813. DOI: 10.1002/14651858.CD003813.pub4 .