Table 5. Assumable recommendations for the final preparation size of the physiological foramen of the first and second maxillary and mandibular molars based on the results obtained.
| 1st MX | Narrow diameter |
Wide diameter |
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|---|---|---|---|---|---|---|---|---|
| Mean | s.d. | IAF | % | Mean | s.d. | IAF | % | |
| MB (S) | 0.24 | 0.08 | 20 | 33.33 | 0.33 | 0.14 | 35 | 42.42 |
| MB (2) | 0.22 | 0.07 | 20 | 31.82 | 0.26 | 0.08 | 25 | 30.77 |
| MB (3) | 0.13 | 0.05 | 15 | 38.46 | 0.15 | 0.06 | 15 | 40.00 |
| DB (S) | 0.22 | 0.06 | 20 | 27.27 | 0.31 | 0.12 | 30 | 38.71 |
| DB (2) | 0.27 | 0.06 | 25 | 27.27 | 0.32 | 0.11 | 30 | 40.00 |
| P (S) | 0.33 | 0.10 | 35 | 30.30 | 0.42 | 0.14 | 40 | 33.33 |
| 2nd MX | Narrow diameter |
Wide diameter |
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| Mean | s.d. | IAF | % | Mean | s.d. | IAF | % | |
| MB (S) | 0.24 | 0.07 | 25 | 29.17 | 0.41 | 0.21 | 40 | 51.22 |
| MB (2) | 0.26 | 0.09 | 25 | 34.62 | 0.41 | 0.08 | 40 | 19.51 |
| MB (3) | 0.26 | 0.08 | 25 | 30.77 | 0.38 | 0.15 | 40 | 39.47 |
| DB (S) | 0.22 | 0.07 | 20 | 31.82 | 0.33 | 0.14 | 35 | 42.42 |
| DB (2) | 0.22 | 0.17 | 20 | 77.27 | 0.32 | 0.11 | 30 | 34.38 |
| P (S) | 0.33 | 0.11 | 35 | 33.33 | 0.44 | 0.15 | 45 | 34.09 |
| 1st MA | Narrow diameter |
Wide diameter |
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| Mean | s.d. | IAF | % | Mean | s.d. | IAF | % | |
| M (S) | 0.24 | 0.07 | 25 | 29.17 | 0.39 | 0.22 | 40 | 56.41 |
| M (2) | 0.25 | 0.10 | 25 | 40.00 | 0.41 | 0.24 | 40 | 58.54 |
| M (3-5) | 0.20 | 0.07 | 20 | 35.00 | 0.32 | 0.12 | 30 | 37.50 |
| D (S) | 0.30 | 0.11 | 30 | 36.67 | 0.46 | 0.18 | 45 | 39.13 |
| D (2) | 0.24 | 0.08 | 25 | 33.33 | 0.36 | 0.19 | 35 | 52.78 |
| D (3-4) | 0.30 | 0.10 | 30 | 33.33 | 0.48 | 0.20 | 50 | 41.67 |
| 2nd MA | Narrow diameter |
Wide diameter |
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| Mean | s.d. | IAF | % | Mean | s.d. | IAF | % | |
| M (S) | 0.25 | 0.09 | 25 | 36.00 | 0.47 | 0.23 | 45 | 48.94 |
| M (2) | 0.25 | 0.10 | 25 | 40.00 | 0.45 | 0.24 | 45 | 53.33 |
| M (3-4) | 0.20 | 0.06 | 20 | 30.00 | 0.33 | 0.16 | 35 | 48.48 |
| D (S) | 0.31 | 0.09 | 30 | 29.03 | 0.47 | 0.16 | 45 | 34.04 |
| D (2) | 0.27 | 0.06 | 25 | 22.22 | 0.38 | 0.10 | 40 | 26.32 |
| D (3) | 0.31 | 0.09 | 30 | 29.03 | 0.47 | 0.16 | 45 | 34.04 |
The determined size of the IAF was calculated according to the mean values of the narrow and wide diameters. Friction at the tip of an instrument at the physiological foramen would be clinically the only conceivable advise that an operator could have to determine the diameter size of the physiological foramen or IAF size. However, due to the limitations inherent to this procedure, it is only the size of the narrow diameter that can be clinically detected; yet, the final preparation size of the physiological foramen should be determined according to the dimension of the wide, and not of the narrow, diameter. The mean figures (%) indicate the possible IAF calculation error margin, according to the resulting s.d., when employing the given IAF recommendations based on the dimensions obtained of either the narrow or wide diameters. 1st, first; 2, two foramina; 2nd, second; 3, three foramina; 3–5, three, four or five foramina; 3–4, three or four foramina; IAF, initial apical files; MA, mandibular; MX, maxillary; S, single foramen; s.d., standard deviations.