Table 2.
Summary of the incidences of documented ethnic and population variations in the anatomy of mandibular second premolars.
| Geographic and ethnic distribution |
Materials and methods |
No. of teeth in the study (n) | Root anatomy | Root canal anatomy | Root canal pattern (Vertucci) |
Apical foramina | References | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 root |
2 roots | >2 roots | 1 canal | 2 canals | >2 canals | C-shaped | Type I | Type II | Type III | Type IV | Type V | Type VI | Type VII | Type VIII | Others types | 1 | 2 | 3 | ||||
| Caucasian | ||||||||||||||||||||||
| France | In vitro: radiograph and sectioning | 328 | 97.6% (320) | 2.4% (8) | 0% (0) |
86.6% (284) | 13.4% (44) | Geider et al. [4], 1989 | ||||||||||||||
| Germany | In vitro: analysis of extracted teeth | 2089 | 99.85% (2086) | 0.05% (1) | 0.1% (2) | Visser [41], 1948 | ||||||||||||||||
| Poland | In vitro: extraction and RCT | 56 | 68.2% (38) | 31.8% (18) | 0% (0) |
0% (0) |
Rózyło et al. [6], 2008 | |||||||||||||||
| U.S.A | In vitro: clearing | 400 | 100% (400) | 0% (0) |
0% (0) |
97.5% (390) | 2.5% (10) | 0% (0) |
0% (0) |
97.5% (390) | 0% (0) |
0% (0) |
0% (0) |
2.5% (10) | 0% (0) |
0% (0) |
0% (0) |
0% (0) |
97.5% (390) | 2.5% (10) | 0% (0) |
Vertucci [7], 1984 |
| In vitro: sectioning | 32 | 100% (32) | 0% (0) |
0% (0) |
65.6% (21) | 34.4% (11) | Barrett [11], 1925 | |||||||||||||||
| In vitro: extraction and radiograph | 906 | 96.6% (902) | 0% (0) |
3.4% (4) | 87.5% (792) | 12.5 (112) |
0.4% (2) | 0% (0) |
Zillich and Dowson [12], 1973 | |||||||||||||
| In vitro: grinding and examination under magnification | 50 | 92% (46) | 8% (4) |
0% (0) |
0% (0) |
96% (48) | 4% (2) | 0% (0) |
Green [9], 1973 | |||||||||||||
| Subgroup ethnic incidence | 3861 | 98.81% | 0.49% | 0.7% | 82.9% | 17.1% | 0.07% | 0% | 97.5% | 2.5% | 96.75% | 3.25% | ||||||||||
|
| ||||||||||||||||||||||
| African | ||||||||||||||||||||||
| Senegalese | In vivo: radiographic examination | 408 | 86% (351) | 12% (49) | 2% (8) |
0% (0) |
Mbaye et al. [15], 2008 | |||||||||||||||
|
| ||||||||||||||||||||||
| Indian | ||||||||||||||||||||||
| India | In vitro: clearing | 40 | 80% (32) | 20% (8) |
0% (0) |
0% (0) |
80% (32) | 0% (0) |
0% (0) |
2.5% (1) | 17.5% (7) | 0% (0) |
0% (0) |
0% (0) |
0% (0) |
80% (32) | 20% (8) | 0% (0) |
Parekh et al. [19], 2011 | |||
| In vitro: SCT | 96 | 97.9% (94) | 2.1% (2) | 0% (0) |
87% (83) | 13.5% (13) | 0% (0) |
0% (0) |
80% (78) | 9% (9) |
3% (3) |
2% (2) |
4% (4) |
0% (0) |
0% (0) |
0% (0) |
0% (0) |
94% (90) | 6% (6) |
0% (0) |
V. K. Sikri and P. Sikri [21], 1994 | |
| Subgroup ethnic incidence | 136 | 97.9% | 2.1% | 0% | 83.5% | 16.75% | 0% | 0% | 80% | 4.5% | 1.5% | 2.25% | 10.75% | 87% | 13% | |||||||
|
| ||||||||||||||||||||||
| Mongoloid | ||||||||||||||||||||||
| China | In vivo: CBCT | 178 | 100% (178) | 0% (0) |
0% (0) |
97.2% (173) | 2.2% (4) |
0% (0) |
0.6% (1) |
97.2% (173) | 0% (0) |
0% (0) |
0.5% (1) | 1.69% (3) | 0% (0) |
0% (0) |
0% (0) |
0.5% (1) |
Tian et al. [25], 2012 | |||
| Japan | In vitro: radiograph | 40 | 97.9% (39) | 2.1% (1) |
0% (0) |
0% (0) |
Miyoshi et al. [29], 1977 | |||||||||||||||
| Korea | CBCT | 789 | 99.4% (784) | 0.6% (5) | 0% (0) |
Park et al. [31], 2013 | ||||||||||||||||
| Subgroup ethnic incidence | 1007 | 99.7% | 0.3% | 0% | 97.5% | 2.15% | 0% | 0.3% | 97.2% | 0.5% | 1.69% | 0.5% | ||||||||||
|
| ||||||||||||||||||||||
| Middle east | ||||||||||||||||||||||
| Kuwait | In vitro: radiograph of RCT teeth | 64 | 95.6% (61) | 4.4% (3) | 0% (0) |
95.3% (61) | 4.7% (3) |
0% (0) |
0% (0) |
95.3% (61) | 4.7% (3) | 0% (0) |
Zaatar et al. [32], 1997 | |||||||||
| Jordan | In vitro: clearing | 400 | 97.2% (389) | 2.8% (11) | 0% (0) |
72% (288) | 27.5% (110) | 0.5% (2) | 0% (0) |
78% (288) | 3.8% (15) | 0.1% (4) | 7.5% (30) | 15.3% (61) | 0% (0) |
0% (0) |
0% (0) |
0.5% (2) |
74.2% (337) | 15.8% (63) | 0% (0) |
Awawdeh and Al-Qudah [33], 2008 |
| Iran | In vitro: clearing | 103 | 100% (103) | 0% (0) |
0% (0) |
80.5% (83) | 17.5% (18) | 0% (0) |
2% (2) |
76.3% (76) | 7.9% (9) | 9.9% (11) | 5.9% (7) | 0% (0) |
0% (0) |
0% (0) |
0% (0) |
0% (0) |
94.1% (97) | 5.9% (6) | 0% (0) |
Rahimi et al. [35], 2007 |
| In vitro: clearing and sectioning | 80 | 88.8% (71) | 11.2% (9) | 0% (0) |
0% (0) |
91.2% (73) | 0% (0) |
0% (0) |
0% (0) |
0% (0) |
0% (0) |
0% (0) |
0% (0) |
0% (0) |
97.5% (78) | 2.5% (2) | 0% (0) |
Hasheminia and Hashemi [39], 2005 | ||||
| In vitro: clearing | 137 | 94.2% (129) | 5.8% (8) |
0% (0) |
0% (0) |
75.9% (104) | 24.1% (33) | 0% (0) |
Rahimi et al. [40], 2009 | |||||||||||||
| Turkey | In vitro: clearing | 100 | 100% (100) | 0% (0) |
0% (0) |
93.6% (94) | 6.4% (6) |
0% (0) |
0% (0) |
93.6% (94) | 0% (0) |
0% (0) |
0% (0) |
6.4% (6) | 0% (0) |
0% (0) |
0% (0) |
0% (0) |
93.6% (94) | 6.4% (6) | 0% (0) |
Çalişkan et al. [36], 1995 |
| In vitro: clearing | 200 | 100% (200) | 0% (0) |
0% (0) |
71% (142) | 29% (58) | 0% (0) |
0% (0) |
71% (142) | 7% (14) | 3.5% (7) | 9% (18) | 7% (14) |
1.5% (3) | 1% (2) |
0% (0) |
0% (0) |
81.5% (163) | 18.5% (37) | 0% (0) |
Sert and Bayirli [37], 2004 | |
| Subgroup ethnic incidence | 1084 | 98.56% | 1.44% | 0% | 85.06% | 14.59% | 0.07% | 0.29% | 82.02% | 3.74% | 2.7% | 4.48% | 5.74% | 0.3% | 0.2% | 0.1% | 87.44% | 11.13% | ||||
|
| ||||||||||||||||||||||
| Hispanic | ||||||||||||||||||||||
| Mexico | In vitro: radiographs | 250 | 98.8% (247) | 1.2% (3) |
0% (0) |
0% (0) |
98.8% (247) | 1.2% (3) | 0% (0) |
Pineda and Kuttler [38], 1972 | ||||||||||||
| Total no of teeth | 6746 | 5649 | 34 | 6 | 3364 | 489 | 12 | 3 | 1346 | 46 | 46 | 58 | 105 | 3 | 2 | 0 | 3 | 1741 | 179 | 0 | ||
| Overall incidence | 99.28% | 0.61 | 0.01% | 86.9% | 12.64% | 0.31% | 0.08% | 83.65% | 2.86% | 2.86% | 3.6% | 6.52% | 0.18% | 0.12% | 0% | 0.18% | 90.68% | 9.32% | 0% | |||