Section (A) Are the results of the review valid?

Screening Questions 1. Did the trial address a clearly focused issue?

Yes. The authors attempted to determine the minimum effective regimen of antibiotic prophylaxis (amoxicillin) for dental implant surgery. The intervention used was amoxicillin 2 g pre-op vs. amoxicillin 2 g daily pre-& post-op (7days) vs. amoxicillin 2 g post-op (7days) vs. placebo.

2. Was the assignment of patients to treatments randomised?

No information regarding the allocation concealment procedure was provided. A computer generated randomisation list was produced to allocate patients into one of four groups.

3. Were all of the patients who entered the trial properly accounted for at its conclusion?

All adults were treated in two private Italian dental practices. Results for all 100 patients (4 groups of 25) who entered the trial were provided at the end of the trial.

Detailed questions 4. Were patients, health workers and study personnel ‘blind’ to treatment?

Operators were not blinded as they were recording the outcome measures.

5. Were the groups similar at the start of the trial?

Size of all four groups were identical (n = 25 for each group). The composition of each group saw slight variations: Amoxicillin 2 g 1 h pre-op (n = 25): 13 (M)/12 (F), mean age = 52 years Amoxicillin 2 g 1 h pre-op + amoxicillin 2 g daily for 7 days post-op (n = 25): 12 (M)/13 (F), mean age = 45 years Amoxicillin 2 g daily post-op for 7 days (n = 25): 7 (M)/18 (F), mean age = 42 years No antibiotic (n = 25): 10 (M)/15 (F), mean age = 43 years The range of total implants per group ranged from 29–48.

6. Aside from the experimental intervention were the groups treated equally?

Yes. All groups were treated at two Italian private dental clinics subject to the same inclusion/exclusion criteria.

Section (B) What are the results?

7. How large was the treatment effect?

Outcomes of interest included: Implant failure: 2 implant failures in no antibiotic group No postoperative complications observed post-op at weeks 1, 2, 4 and 8 Adverse events: none reported

8. How precise was the estimate of the treatment effect?

Power analysis showed only 15% with confidence at 99% and 35% at 95% CI. However further calculations revealed that in order to achieve a power of 75% with 99% confidence, 133 samples are required in each group; a much larger quantity than the current 25 per group is required to further provide strong statistical evidence of the absence of treatment effect.

Section (C) Will the results help locally?

9. Can the results be applied in your context? (or to the local population?)

Results may not be generalisable to a whole general population. Patients did not comprise of the elderly, young children, immunocompromised patients or those at risk of IE. A larger sample size would be required.

10. Were all clinically important outcomes considered?

Yes. All outcomes considered and reported. A different dosing regimen group could also have been tested.

11. Are the benefits worth the harms and costs?

Not in this case. Insufficient statistically significant evidence (p > 0.05). No adverse events were reported but this may be due to the small sample size of the study. Amoxicillin is relatively cheap in the UK but the risk of other complications such as microbial resistance may outweigh the benefit if it is to be routinely prescribed for a procedure which fails to show statistically significant results.