TABLE 4.

Multivariate analysis of implant failure including the two study groups and potential confounding variables

Variable	Odds ratio	95% CI
Smoking
No	Ref
Yes	1.4	0.4–5.6
Age (years)
<50	Ref
50–64	4.3	0.5–37.0
≥65	4.4	0.5–38.5
Number of implants
1	Ref
2–3	2.2	0.6–7.3
≥4	2.9	0.5–16.0
Bone augmentation
No	Ref
Yes	1.7	0.5–5.5
Treatment group
Antibiotics	Ref
Placebo	1.2	0.4–3.6

Abbreviations: CI , confidence interval; Ref, reference.