Table 4. Estimation of the Gas Cavity Volume and the Total Gas Volume from the Literature7.
| follow-up period (w) | tissue | ave./max | radiolucency areas (mm)7 | gas cavity volume (mm3)a | gas capture ratio (%)b | total gas volume (mm3)c |
|---|---|---|---|---|---|---|
| 6 | bone | ave | 2.0 ± 1.3 | 4.19 ± 8.2 | 0.04 ± 0.07 | 11,390 |
| max | 6 | 113 | 0.99 | |||
| soft tissue | ave | 3.0 ± 3.0 | 14.1 ± 42.4 | 0.12 ± 0.37 | ||
| max | 11 | 697 | 6.1 | |||
| 12 | bone | ave | 1.5 ± 0.9 | 1.77 ± 3.2 | 0.008 ± 0.014 | 22,780 |
| max | 2.8 | 11.5 | 0.05 | |||
| soft tissue | ave | 1.0 ± 1.8 | 0.524 ± 2.8 | 0.002 ± 0.012 | ||
| max | 5.7 | 97.0 | 0.43 |
a
Gas cavity volume is calculated assuming a sphere with a diameter of the average and the maximum value of the maximum length of X-ray transparency reported.7
b
Gas capture ratio is defined as the gas cavity volume divided by the total gas volume.
c
Total gas volume is calculated as an ideal gas based on the following assumptions: the weight of the WE43-based compression screw as 150 mg, and its degradation period as 18 months (the average values of the degradation period appears on the implant brochure32) with a constant degradation rate through the period.