Abstract: Six RCTs with 1162 participants were included: three trials compared 2 g of preoperative amoxicillin versus placebo (927 participants), one compared 3 g of preoperative amoxicillin versus placebo (55 participants), one compared 1 g of preoperative amoxicillin plus 500 mg four times a day for two days versus no antibiotics (80 participants), and one compared four groups: (1) 2 g of preoperative amoxicillin; (2) 2 g of preoperative amoxicillin plus 1 g twice a day for seven days; (3) 1 g of postoperative amoxicillin twice a day for seven days, and (4) no antibiotics (100 participants). The overall body of evidence was considered to be of moderate quality. The meta-analyses of the six trials showed a statistically significant higher number of participants experiencing implant failures in the group not receiving antibiotics (RR 0.33; 95% CI 0.16 to 0.67, P value 0.002, heterogeneity: Tau2 0.00; Chi2 2.87, df = 5 (P value 0.57); I2 0%). The number needed to treat for one additional beneficial outcome (NNTB) to prevent one person having an implant failure is 25 (95% CI 14 to 100), based on an implant failure rate of 6% in participants not receiving antibiotics. There was borderline statistical significance for prosthesis failures (RR 0.44; 95% CI 0.19 to 1.00), with no statistically significant differences for infections (RR 0.69; 95% CI 0.36 to 1.35), or adverse events (RR 1; 95% CI 0.06 to 15.85) (only two minor adverse events were recorded, one in the placebo group). No conclusive information can be derived from the only trial that compared three different durations of antibiotic prophylaxis since no event (implant/prosthesis failures, infections or adverse events) occurred in any of the 25 participants included in each study group. There were no trials that evaluated different antibiotics or different antibiotic dosages. Scientific evidence suggests that, in general, antibiotics are beneficial for reducing failure of dental implants placed in ordinary conditions. Specifically 2 g or 3 g of amoxicillin given orally, as a single administration, one hour preoperatively significantly reduces failure of dental implants. No significant adverse events were reported. It might be sensible to suggest the use of a single dose of 2 g prophylactic amoxicillin prior to dental implant placement. It is still unknown whether postoperative antibiotics are beneficial, and which antibiotic is the most effective.

Plain-language summary: The evidence on which this review is based was up to date as of 17 June 2013. Six trials were included with a total of 1162 participants. All six of these trials compared the use of antibiotics to prevent infection (failures and complications) with no treatment or treatment with a placebo (a fake medicine with no active ingredient). The antibiotic used in all the trials was amoxicillin; doses and timing of doses varied, although most used a single dose taken just before the implant was placed. One of the trials, with 100 participants, also looked at different doses of amoxicillin taken at different times. There were no trials that looked at alternative antibiotics. Participants were people over 18 years of age who were able to give consent to taking part in a medical trial. Potential participants were excluded for a variety of reasons that included: if they were at risk of heart disease, had artificial joints, had problems with their immune system, were affected by diabetes, had received radiotherapy in the head and neck area, had need of additional procedures at the time of implant placement, were allergic to penicillin, had chronic/acute infections near the planned implant site, were already receiving antibiotic treatment for any other reasons (or had taken them up to six months previously), had been treated with or were receiving intravenous amino-bisphosphonates, were pregnant or breast feeding, were receiving long-term nonsteroidal anti-inflammatory drug therapy, or had blood clotting problems. The follow-up period in all the trials was at least three months. It appears that the oral administration of two grams of amoxicillin one hour before placement of dental implants is effective in reducing implant failures. More specifically, giving antibiotics to 25 people will avoid one person experiencing early implant losses. It is still unclear whether postoperative antibiotics are beneficial, or which antibiotics work best. The evidence from the six trials (1162 participants) that compared the use of antibiotics with placebo or no treatment was considered to be of moderate quality. However, the one trial (100 participants) that investigated antibiotics given for different lengths of time was found to be at high risk of bias.