TABLE 2.
Hazard ratios obtained from univariate Cox PH regressions
| Hazard ratio | 95% CI | Robust p value | Violation of the PH assumption | |
|---|---|---|---|---|
| Demographic variables | ||||
| Gender | ||||
| Male | 1 | |||
| Female | 0.83 | (0.58, 1.18) | 0.3 | No |
| Age at 1st surgery (years) | 0.99 | (0.98, 1.01) | 0.68 | No |
| Health status variables | ||||
| Diabetes mellitus | ||||
| No | 1 | |||
| Yes | 2.17 | (1.01, 4.68) | 0.048 | No |
| Periodontal disease | ||||
| No | 1 | |||
| Yes | 1.77 | (0.89, 3.51) | 0.10 | No |
| Heavy smoking (>10 pack‐years) | ||||
| No | 1 | |||
| Yes | 2.02 | (1.13, 3.59) | 0.017 | No |
| Implant specific variables | ||||
| Diameter (mm) | 1.45 | (0.99, 2.11) | 0.051 | 0.04 |
| Length (mm) | 0.85 | (0.78, 0.92) | <0.01 | 0.02 |
| 6 mm implant | ||||
| No | 1 | No | ||
| Yes | 3.53 | (2.25, 5.55) | <0.01 | |
| Straumann design | ||||
| Standard (2.8 mm) | 1 | <0.01 | ||
| Standard Plus (1.8 mm) | 1.77 | (0.41, 7.64) | 0.44 | |
| Tapered Effect (1.8 mm) | 2.90 | (1.07, 7.89) | 0.04 | |
| Bone Level | 0.74 | (0.38, 1.43) | 0.38 | |
| Bone level taper | 2.97 | (0.70, 12.62) | 0.14 | |
| not Straumann | 1.31 | (0.85, 2.02) | 0.22 | |
| Multiple implants | ||||
| Single implant | 1 | |||
| 2 or more implants per patient | 5.85 | (2.14, 15.94) | <0.01 | No |
| Surgical and site specific variables | ||||
| Jaw | ||||
| Mandible | 1 | |||
| Maxilla | 1.37 | (0.96, 1.95) | 0.09 | <0.01 |
| Location | ||||
| Anterior Mandible | 1 | 0.01 | ||
| Posterior Mandible | 0.87 | (0.41, 1.84) | 0.72 | |
| Anterior Maxilla | 1.15 | (0.53, 2.47) | 0.73 | |
| Posterior Maxilla | 1.27 | (0.61, 2.65) | 0.53 | |
| Immediate implantation | ||||
| No | 1 | |||
| Yes | 1.78 | (1.14, 2.78) | 0.01 | <0.01 |
| Loading | ||||
| Delayed | 1 | |||
| Immediate | 1.14 | (0.56, 2.31) | 0.72 | No |
| GBR surgery | ||||
| No | 1 | |||
| Yes | 1.85 | (1.32, 2.62) | <0.01 | No |
| Insertion torque (N cm) | 0.98 | (0.96, 1.01) | 0.10 | <0.01 |