The effects of antibiotics on toothache caused by inflammation or infection at the root of the tooth in adults

This Cochrane Review has been produced to assess the effects of antibiotics on the pain and swelling experienced by adults in two conditions commonly responsible for causing dental pain. The review set out to assess the effects of taking antibiotics when provided with, or without, dental treatment.


Dental pain is a common problem and can arise when the nerve within a tooth dies due to progressing decay or injury. Without treatment, bacteria can infect the dead tooth and cause a dental abscess, which can lead to swelling and spreading infection, which can occasionally be life threatening.

The recommended treatment for these forms of toothache is removal of the dead nerve and associated bacteria. This is usually done by extraction of the tooth or root canal treatment (a procedure where the nerve and pulp are removed and the inside of the tooth cleaned and sealed). Antibiotics are only recommended when there is severe infection that has spread from the tooth into the surrounding tissues. However, some dentists still routinely prescribe oral antibiotics to patients with acute dental conditions who have no signs of spreading infection, or without dental treatment to remove the infected material.

Use of antibiotics contributes to the development of antibiotic-resistant bacteria. It is therefore important that antibiotics are only used when they are likely to result in benefit for the patient. Dentists prescribe approximately 8% to 10% of all primary care antibiotics in high-income countries, and therefore it is important to ensure that dentists have good information about when antibiotics are likely to be beneficial for patients.

Study characteristics

The evidence on which this review is based was up-to-date as of 26 February 2018. We searched scientific databases and found two trials, with 62 participants included in the analysis. Both trials were conducted at dental schools in the USA and evaluated the use of oral antibiotics in the reduction of pain and swelling reported by adults after having the first stage of root canal treatment under local anaesthetic. The antibiotic used in both trials was penicillin VK and all participants also received painkillers.

Key results

The two studies included in the review reported that there were no clear differences in the pain or swelling reported by participants who received oral antibiotics compared with a placebo (a dummy treatment) when provided alongside the first stage of root canal treatment and painkillers. However, the studies were small and produced poor quality evidence, and therefore we cannot be certain if the results are correct. Neither study examined the effect of antibiotics on their own, without surgical dental treatment.

One trial reported side effects among participants: one person who received the placebo medication had diarrhoea and one person who received antibiotics experienced tiredness and reduced energy after their treatment.

Quality of evidence

We judged the quality of evidence to be very low. There is currently insufficient evidence to be able to determine the effects of antibiotics in these conditions.

Authors' conclusions: 

There is very low-quality evidence that is insufficient to determine the effects of systemic antibiotics on adults with symptomatic apical periodontitis or acute apical abscess.

Read the full abstract...

Dental pain can have a detrimental effect on quality of life. Symptomatic apical periodontitis and acute apical abscess are common causes of dental pain and arise from an inflamed or necrotic dental pulp, or infection of the pulpless root canal system. Clinical guidelines recommend that the first-line treatment for teeth with these conditions should be removal of the source of inflammation or infection by local, operative measures, and that systemic antibiotics are currently only recommended for situations where there is evidence of spreading infection (cellulitis, lymph node involvement, diffuse swelling) or systemic involvement (fever, malaise). Despite this, there is evidence that dentists frequently prescribe antibiotics in the absence of these signs. There is concern that this could contribute to the development of antibiotic-resistant bacterial colonies within both the individual and the community. This review is an update of the original version that was published in 2014.


To evaluate the effects of systemic antibiotics provided with or without surgical intervention (such as extraction, incision and drainage of a swelling, or endodontic treatment), with or without analgesics, for symptomatic apical periodontitis and acute apical abscess in adults.

Search strategy: 

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 26 February 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 1) in the Cochrane Library (searched 26 February 2018), MEDLINE Ovid (1946 to 26 February 2018), Embase Ovid (1980 to 26 February 2018), and CINAHL EBSCO (1937 to 26 February 2018). The US National Institutes of Health Ongoing Trials Register ( and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. A grey literature search was conducted using OpenGrey (to 26 February 2018) and ZETOC Conference Proceedings (1993 to 26 February 2018). No restrictions were placed on the language or date of publication when searching the electronic databases.

Selection criteria: 

Randomised controlled trials of systemic antibiotics in adults with a clinical diagnosis of symptomatic apical periodontitis or acute apical abscess, with or without surgical intervention (considered in this situation to be extraction, incision and drainage or endodontic treatment) and with or without analgesics.

Data collection and analysis: 

Two authors screened the results of the searches against inclusion criteria, extracted data and assessed risk of bias independently and in duplicate. We calculated mean differences (MD) (standardised mean difference (SMD) when different scales were reported) and 95% confidence intervals (CI) for continuous data. A fixed-effect model was used in the meta-analysis as there were fewer than four studies. We contacted study authors to obtain missing information.

Main results: 

We included two trials in this review, with 62 participants included in the analyses. Both trials were conducted in university dental schools in the USA and compared the effects of oral penicillin V potassium (penicillin VK) versus a matched placebo when provided in conjunction with a surgical intervention (total or partial pulpectomy) and analgesics to adults with acute apical abscess or symptomatic necrotic tooth. The patients included in these trials had no signs of spreading infection or systemic involvement (fever, malaise). We assessed one study as having a high risk of bias and the other study as having unclear risk of bias.

The primary outcome variables reported in both studies were participant-reported pain and swelling (one trial also reported participant-reported percussion pain). One study reported the type and number of analgesics taken by participants. One study recorded the incidence of postoperative endodontic flare-ups (people who returned with symptoms that necessitated further treatment). Adverse effects, as reported in one study, were diarrhoea (one participant, placebo group) and fatigue and reduced energy postoperatively (one participant, antibiotic group). Neither study reported quality of life measurements.

Objective 1: systemic antibiotics versus placebo with surgical intervention and analgesics for symptomatic apical periodontitis or acute apical abscess
Two studies provided data for the comparison between systemic antibiotics (penicillin VK) and a matched placebo for adults with acute apical abscess or a symptomatic necrotic tooth when provided in conjunction with a surgical intervention. Participants in one study all underwent a total pulpectomy of the affected tooth, while participants in the other study had their tooth treated by either partial or total pulpectomy. Participants in both trials received oral analgesics. There were no statistically significant differences in participant-reported measures of pain or swelling at any of the time points assessed within the review. The MD for pain (short ordinal numerical scale 0 to 3) was -0.03 (95% CI -0.53 to 0.47) at 24 hours; 0.32 (95% CI -0.22 to 0.86) at 48 hours; and 0.08 (95% CI -0.38 to 0.54) at 72 hours. The SMD for swelling was 0.27 (95% CI -0.23 to 0.78) at 24 hours; 0.04 (95% CI -0.47 to 0.55) at 48 hours; and 0.02 (95% CI -0.49 to 0.52) at 72 hours. The body of evidence was assessed as at very low quality.

Objective 2: systemic antibiotics without surgical intervention for adults with symptomatic apical periodontitis or acute apical abscess
We found no studies that compared the effects of systemic antibiotics with a matched placebo delivered without a surgical intervention for symptomatic apical periodontitis or acute apical abscess in adults.