Table 2. Comparison of screw loosening, fracture and cumulative fracture rate (CFR) in gender, age, bone graft, length of implant, position, jawbone and type of diameter.
| Screw loosening (n = 10) | Fracture (n = 10) | ||||||
|---|---|---|---|---|---|---|---|
| No (%) | P value* | No (%) | 5yr CFR | 8yr CFR | P value† | ||
| Gender | Male | 7/251 (2.8) | .360 | 8/251 (3.2) | 2.50% | 4.20% | .159 |
| Female | 3/199 (1.5) | 2/199 (1.0) | 1.00% | 1.00% | |||
| Age | Young (15 - 39 years) | 4/94 (4.3) | .311 | 0/94 (0.0) | 0.00% | 0.00% | .031 |
| Middle (40 - 65 years) | 5/278 (1.8) | 10/278 (3.6) | 3.10% | 5.30% | |||
| Old (> 65 years) | 1/78 (1.3) | 0/78 (0.0) | 0.00% | 0.00% | |||
| Length | 8 mm | 2/82 (2.4) | .864 | 3/82 (3.7) | 3.70% | 3.70% | .538 |
| 9.5 mm | 3/150 (2.0) | 2/150 (1.3) | 0.80% | 3.70% | |||
| 11 mm | 5/195 (2.6) | 4/195 (2.1) | 1.60% | 2.80% | |||
| 14 mm | 0/25 (0.0) | 1/25 (4.0) | 4.20% | 4.20% | |||
| Type of diameter | 3.5 mm | 4/200 (2.0) | .908 | 1/200 (0.5) | 0.50% | 0.50% | .044‡ |
| 4.5 mm | 5/218 (2.3) | 7/218 (3.2) | 2.30% | 4.50% | |||
| 5.5 mm | 1/32 (3.2) | 2/32 (6.5) | 6.70% | 6.70% | |||
| Position | Anterior | 2/100 (2.0) | .330 | 1/100 (1.0) | 1.10% | 1.10% | .027 |
| Premolar | 1/130 (0.8) | 0/130 (0.0) | 0.00% | 0.00% | |||
| Molar | 7/220 (3.2) | 9/220 (4.1) | 3.30% | 5.80% | |||
| Mandible | 3/197 (1.5) | .524 | 5/197 (2.5) | 2.10% | 3.50% | .716 | |
| Maxillary | 7/253 (2.8) | 5/253 (2.0) | 1.70% | 2.80% | |||
| Bone graft | Yes | 4/121 (1.8) | .472 | 2/121 (1.6) | 1.70% | 1.70% | .684 |
| No | 6/327 (3.3) | 8/327 (2.4) | 2.00% | 3.30% | |||
*a chi-square test or a Mann-Whitney rank sum test
†Estimated Cumulative rate and P value from Kaplan-Meier analysis with Log-Rank test
‡In post-hoc analysis, only P value <.05 in 3.5 mm diameter vs 4.5 mm or 5.5 mm diameter, and there were no significant difference between 4.5 mm diameter and 5.5 mm diameter (P=.296)