Table 4 Multivariate Cox proportional hazards regression analyses for risk factors potentially affecting the tooth loss
variable | hazard ratio | std. error | 95% Confidence interval | z-score | P-value | |
|---|---|---|---|---|---|---|
Age (reference: 20–29 years) |  |  |  |  |  |  |
 30–39 | 0.00 | 0.00 | 0.00 | - | 0.00 | 0.999 |
 40–49 | 0.08 | 856.95 | 0.00 | - | 0.00 | 1.000 |
 50–59 | 0.03 | 367.45 | 0.00 | - | 0.00 | 1.000 |
 60–69 | 0.18 | 1,915.84 | 0.00 | - | 0.00 | 1.000 |
 70–79 | 0.00 | 0.00 | 0.00 | - | 0.00 | 0.999 |
 80–89 | 0.74 | 14,722.86 | 0.00 | - | 0.00 | 1.000 |
Sex (reference: male) | Â | Â | Â | Â | Â | Â |
 Female | 1.32 | 1.03 | 0.29 | 6.11 | 0.36 | 0.720 |
Smoking status (reference: non-smoker) | Â | Â | Â | Â | Â | Â |
 Current smoker | 3.08 | 3.19 | 0.40 | 23.51 | 1.08 | 0.278 |
Hypertension (reference: no) | Â | Â | Â | Â | Â | Â |
 Yes | 4.17 | 3.23 | 0.91 | 19.06 | 1.84 | 0.065 |
Diabetes mellitus (reference: no) | Â | Â | Â | Â | Â | Â |
 Yes | 44.57 | 57.48 | 3.56 | 558.20 | 2.94 | 0.003** |
Position (reference: maxillary anterior) | Â | Â | Â | Â | Â | Â |
 Maxillary premolar | 0.00 | 0.00 | 0.00 | - | -0.01 | 0.994 |
 Maxillary molar | 13.08 | 14.64 | 1.46 | 117.24 | 2.30 | 0.022* |
 Mandibular anterior | 2.55 | 3.07 | 0.24 | 27.12 | 0.77 | 0.438 |
 Mandibular premolar | 0.00 | 0.00 | 0.00 | - | -0.01 | 0.992 |
 Mandibular molar | 1.38 | 1.35 | 0.20 | 9.36 | 0.33 | 0.741 |
Defect morphology (reference: three-wall) | ||||||
 One-wall | 18.73 | 17.43 | 3.02 | 116.09 | 3.15 | 0.002** |
 Two-wall | 4.93 | 4.96 | 0.69 | 35.41 | 1.58 | 0.113 |
With xenograft (reference: no) | Â | Â | Â | Â | Â | Â |
 Yes | 0.75 | 0.48 | 0.21 | 2.63 | -0.45 | 0.653 |