The overall aim of the study is to investigate whether routine administration of antibiotic prophylaxis 1 hour prior to implant surgery may prevent postoperative infection and implant loss in healthy or substantially healthy patients (ASA Class 1 and Class 2).

The prevalence of bacteria resistant to antibiotics is increasing and there is a correlation between high consumption of antibiotics and high incidence of antibiotic resistance. It is therefore important to reduce the prescription of antibiotics. Antibiotics in dental care are used to treat oral infections as well as to prevent infections associated with surgical procedures. An example of the latter is antibiotic prophylaxis associated with dental implant surgery in order to reduce the risk of postoperative infection that can lead to loss of implant.The study will be conducted as a multicenter placebo-controlled randomized clinical trial. Eligible patients will be asked for participation and those who leave oral and written information will be included in the study. Patients included will be allocated to either active treatment (antibiotic prophylaxis) or placebo. Both clinicians and patients will be blinded to group affiliation. A total of 10 clinicians in 8 centers in the south of Sweden have agreed to participate and each clinicians will be allowed to use the implants and routines that they usually work with.

Specific aims of the study are to test the following hypotheses:

1. There is no difference in proportion of patients with early implant losses in patients receiving 2 g of amoxicillin preoperatively and patients receiving identical placebo tablets.
2. There is no difference in proportion of patients with early infections between patients receiving 2 g of amoxicillin preoperatively and patients receiving identical placebo tablets.
3. There is no difference in infections (within 3-6 months postoperatively) between patients receiving 2 g of amoxicillin preoperatively and patients receiving identical placebo tablets.

If it appears that antibiotic prophylaxis does not lead to any risk reduction, this result may provide a basis for guidelines rejecting antibiotic prophylaxis in dental implant surgery.

Inclusion Criteria:

• Requirement for dental implant placement
• Over 18 years of age

Exclusion Criteria:

• Immunosuppressed or immunocompromised
• Affected by not controlled diabetes
• Serious or severe systemic disease (ASA classification > 2)
• Previous radiotherapy to the head or neck area
• Ongoing acute or chronic infection in the oral cavity
• Ongoing treatment with antibiotics
• Hypersensitivity to penicillin
• Previous or ongoing treatment with bisphosphonates
• In need of major bone augmentation
• Planned direct loading or early loading (within 2 weeks) of the implant

The tablets corresponding to each patient is packed in a container by the manufacturer of the trial drug. Each drug container is labeled by a code number (1-1000) and the contents of the containers are distributed according to a randomization list with block size 6. Randomization is thus carried out by the manufacturer, independent of investigator and participating clinicians.