International Journal of Dentistry 5 Table 4: Response details for NTRF usage and place of graduation. Table 7: Response details for NTRF usage according to region. Participants who Use NiTi Do not use Place of graduation perform RCT (%)a NiTi (%)a Saudi Arabia 211 145 (68.7) 66 (31.3) North America 23 20 (87)∗∗ 3 (13) (USA, Canada) Europe and 23 23 (100)∗∗ 0 (0) Australia Africa 31 16 (51.6) 15 (48.4) Asia 104 66 (63.5) 38 (36.5) Others 14 3 (21.4) 11 (78.5) a The percentage valued between parenthesis refers to each group, ∗∗(χ2 = 19.64, P = 0.001). Table 5: Response details for RCT performance and NTRF in relation to gender. Participants who Use NiTi Do not use NiTi Gender perform RCT (%)a (%)a Male 263 192 (73)∗∗ 71 (27) Female 143 81 (56.6) 62 (43.4) a The percentage valued between parenthesis refers to each group, ∗∗(χ2 = 11.26, P = 0.001). Table 6: Response details for NTRF usage and type of practice. Place of practice Participants who perform RCT Use NiTi (%)a Do not use NiTi (%)a University 86 48 (55.8) 38 (44.2) Ministry of Health 96 58 (60.4) 38 (39.6) Hospital Ministry of Defense 49 46 (93.9)∗∗ 3 (6.1) Hospital Ministry of Interior 13 11 (84.6) 2 (15.4) Hospital National Guard 17 15 (88.2) 2 (11.8) Hospital Private Hospital 25 18 (72) 7 (28) Private Dental Clinic 71 51 (71.8) 20 (28.2) Medical Polyclinic 39 21 (53.8) 18 (46.2) (has dental clinic) Others 10 5 (50) 5 (50) a The percentage valued between parenthesis refers to each group, ∗∗(χ2 = 33.56, P < 0.001). 2001 and 2010—78.4% and 63.5%, respectively (χ2 = 7.80, P = 0.05; Table 3). Parashos and Messer have shown a similar pattern of re- duction of NTRF use from the decade 1981–1990 (31%) to the decade 1991–2000 (17%) [7]. In both this study and our own, the reduction in usage was signiﬁcant among less-expe- rienced dentists. Our results showed a signiﬁcant relationship between place of graduation and usage of NTRF—P = 0.001 (Table 4). All 23 dentists who graduated in Europe or Region Participants who Use NiTi Do not use NiTi of perform RCT (%)a (%)a practice Central 188 137 (72.9) 51 (27.1) West 107 69 (64.5) 38 (35.5) East 73 43 (58.9) 30 (41.1) South 20 13 (65) 7 (35) North 9 7 (77.8) 2 (22.2) a The percentage valued between parenthesis refers to each group, no sig- niﬁcant ﬁnding (χ2 = 5.88, P = 0.2). Table 8: Reasons preventing the usage of NTRF. Reasons preventing the usage Never used Users of NiTi (%)a of NiTi NiTib (%)a Not available 52 (19) 86 (64.7)∗ Lack of experience 23 (8.4) 72 (54.1)∗∗ Lack of knowledge or 18 (6.6) 39 (29.3)∗ continuous education Fear of perforation 24 (8.8) 17 (12.8) Fear of breakage 84 (30.8)∗∗ 15 (11.3) Too expensive 53 (19.4)∗∗ 11 (8.3) Do not see an advantage over 10 (3.7) 8 (6) hand ﬁles Diﬃcult to learn and use 1 (0.4) 6 (4.5) Not seeing a lot of patients 2 (0.7) 5 (3.8) needing root canal treatment No reason preventing me to 114 (41.8)∗∗ 5 (3.8) use them Other reasons 7 (2.6) 5 (3.8) a The percentage valued between parenthesis refers to each group, Signiﬁcant at ∗∗(P ≤ 0.001); ∗(P ≤ 0.05), bReasons preventing NTRF usage among nonuser group in descending order. Australia used NTRF. We cannot explain the reason for this at the present time, but we believe that the manufacturing of NTRF in Europe may have had an impact on dental practice within that continent and therefore on these results. We then tested the relationship between gender and per- formance of endodontic treatment and found a signiﬁcant diﬀerence; 86.8% of the male doctors performed RCT versus 75.4% of the females (Table 5) (P = 0.001). There was a signiﬁcant diﬀerence between males and females for NTRF usage (73%, 56.6%; resp.) (P = 0.001). Currently, we cannot ﬁnd an explanation for the eﬀect of gender on RCT or NTRF. We did not expect to ﬁnd that more than 45% of the participants working at universities were not using NTRF (Table 6). Therefore, we checked the curriculum of all the endodontic courses in those universities and found that NTRF was introduced only in the last 2-3 years. Conversely, over 90% of dentists working in military hospitals were using NTRF. A possible rationale for this is the existence of an Advanced Education for General Dentist’s program, which is being supervised by endodontists, in military hospitals. Another possible explanation is the similarity between their