Table 1.
Descriptive statistics for convergence angle, marginal reduction, marginal design (defined finish point, featheredge design, reverse bevel), homogeneity of the finish line (maximum difference between two adjacent preparation points), and undercuts
| Group | Parameter | ||||
|---|---|---|---|---|---|
| Convergence angle [%] | Classification of convergence angle [%] | ||||
| Median (IQR) | Mean (SD) | Class I, 6°–15° | Class II, < 6° | Class, III > 15° | |
| ID | 30.79 (9.19) | 30.48 (6.84) | 8.1 | 3.5 | 88.4 |
| IS | 33.32 (8.98) | 32.85 (7.07) | 7.7 | 2.4 | 89.9 |
| Marginal reduction [mm] | Classification of marginal reduction [%] | ||||
| Median (IQR) | Mean (SD) | Class I, 0.5–1 mm | Class II, > 1 mm | Class III, < 0.5 mm | |
| ID | 0.72 (0.16) | 0.71 (0.14) | 29.5 | 26.4 | 44.1 |
| IS | 0.67 (0.19) | 0.67 (0.12) | 33.1 | 31.4 | 35.5 |
| Marginal design | |||||
| Defined finish point [%] | Featheredge design [%] | Reverse bevel [%] | |||
| Median (IQR) | Mean (SD) | Median (IQR) | Mean (SD) | ||
| ID | 96.9 (6.9) | 94,4 (6.6) | 15.6 (22.2) | 20.0 (17.1) | 42.3 |
| IS | 99.2 (2.8) | 97.4 (4.2) | 10.0 (18.1) | 14.1 (14.4) | 35.9 |
| Homogeneity of the finish line [mm] | Undercuts [%] | ||||
| Median (IQR) | Mean (SD) | Median (IQR) | Mean (IQR) | ||
| ID | 0.07 (0.02) | 0.07 (0.02) | 4.7 (12.5) | 8.2 (9.8) | |
| IS | 0.06 (0.01) | 0.07 (0.01) | 1.4 (9.2) | 6.1 (9.4) | |