Table 2 Correlation of the visual acuity tests with parameters of preparation precision
Preparation | Parameter | Conventional visual acuity test | Near vision acuity test | ||
|---|---|---|---|---|---|
Spearman rank correlation coefficient | p value | Spearman rank correlation coefficient | p value | ||
S figure | Accuracy | 0.13 | 0.2562 | 0.28 | 0.2976 |
Length of inaccurate preparation | − 0.11 | 0.3173 | − 0.22 | 0.0531 | |
O figure | Depth of the outer cavity | 0.17 | 0.4558 | 0.18 | 0.3658 |
Evenness of the outer cavity floor | − 0.11 | 0.0053 | − 0.05 | 0.1401 | |
Depth of the inner cavity | 0.09 | 0.9417 | 0.04 | 0.3080 | |
Evenness of the inner cavity floor | − 0.06 | 0.7220 | − 0.08 | 0.8490 | |
Number of ledges | − 0.20 | 0.0683 | − 0.03 | 0.0440 | |
Internal angles of the axial walls | − 0.11 | 0.5920 | − 0.23 | 0.0937 | |