4 them from usage” (41.8%, P ≤ 0.001). However, they also reported that if there was any reason that may prevent them from using NTRF in the future; it would be “fear of breakage” (30.8%, P ≤ 0.001), followed by “being expensive” (19.4%, P ≤ 0.001) (Table 8). 4. Discussion There have been several publications on NTRF usage in several countries, including Australia [7, 8], Sudan [5], Denmark [6], Belgium [9], Sweden [10], and, more recently, in the United States of America [11]. However, unfortunately no such information exists with regard to Saudi Arabia, which is considered one of the biggest markets for NTRF in the Arabic Gulf region. Therefore, the aim of this study was to collect and analyze data regarding the demographics and usage of NTRF among dentists residing in Saudi Arabia. In contrast with the study by Parashos and Messer [7], in which the surveys were mailed to the target group, we utilized online questionnaires because we considered that mail may not be a reliable method of questionnaire distribution in Saudi Arabia. Moreover, use of an online survey is a fast and cost-eﬀective way to distribute data to a relatively large target group and oﬀers simple collection and analysis of feedback. Furthermore, the study investigator(s) can easily follow up with the target group and can send reminder emails to those who did not complete the survey. This kind of survey has a unique advantage over mailed hard-copy questionnaires; in that, in the online version, the participant cannot go to the next question without answering the present one. Moreover, all answers must be completed in order to submit the survey. However, one of the biggest disadvantages of online surveys is that they exclude participants who do not have emails, and/or those who do not open their emails at the time of the survey, which may result in biased outcome. In our study, we achieved a 30.6% response rate from the large number of dentists practicing across diﬀerent regions of the country. This is close to the response rate achieved by Bird et al. [11]. Although the response rate was relatively low in our study, the total sample number of targeted candidates was larger than that used in most of the previous studies [6, 11]. Moreover, our response rate was higher than some studies with a large sample size, for example, that conducted by Slaus and Bottenberg (n = 4545) in which the response rate was 25% [9]. In order to achieve our aim of assessing the adoption and usage of NTRF among dentists residing in Saudi Arabia, we initially had to ask them if they perform endodontic procedures. We covered a wide array of specialties; therefore, in order to make the analysis simpler, and groups that have similar postgraduate level requirements were merged together, as seen in Table 1. The percentage of practitioners in our study who per- formed endodontic treatment was 82.8% (n = 406) of all the participants (n = 490) and almost 90% of general practitioners (Table 1). Our results were similar to a previous International Journal of Dentistry study that was conducted in Illinois, United States of America, where 90% of the dentists investigated performed RCT [12]. However, we reported higher RCT performance compared to that of other developing countries, for example, 67% in Kenya [13]. In a study conducted in Sudan, 85% of the dentists that were studied conducted endodontic treatment; however, the sample size was only 55 dentists, all of whom were working in one city [5]. In Table 1, two participants within the Endodontists and the Saudi Board in Endodontics group reported that they were not performing RCT. When we reviewed the demographics, we noticed that they were senior practitioners. Since our exclusive criteria did not include Endodontists who is not currently practicing, we included them in the statistics. We might think that they may have stopped practicing because of retirement or being occupied with other tasks such as administration. In our study, of the entire sample that performed endo- dontic treatment, 67.2% were NTRF users. However, when examining within the subgroups, we found that 52% of the general dentists and 91.5% of the Endodontist and the Saudi Board in Endodontics used NTRF. The Saudi Board in Endodontics is a four-year residency, in which the residents are asked to submit double the requirement for any two-year endodontic program. The percentage of NTRF usage across all dentists in Saudi Arabia is considered low when compared to NTRF usage among dentists and endodontists in the United States of America, which is 84% and 98%, respectively [11, 14]. However, our results compared favourably with those of some other countries, such as Finland, where only 28% of the 309 dentists use NTRF solely for shaping the canals of the teeth [14]. The AEGD and Saudi Board in Restorative Dentistry are two- and four-year residency programs, respectively. Both these programs have the same requirements as any endodontic program accredited by the American Association of Endodontists; therefore, the usage of NTRF was considerably high (97.1%) in this group. However, that might not explain why this group had higher usage of NTRF than the Endodontist group. Therefore, we felt it was necessary to identify the reasons that prevented the two endodontists (out of 32 endodontists) from using NTRF and found that the primary ones were unavailability of the NTRF and fear of breakage. Another possible reason is the eﬀect of seniority and the diﬃculty of adopting a new technique. The three participants from the Saudi Board in Endodontics group who did not use NTRF reported that the main reasons for this were lack of experience or unavailability. We then assessed the adoption of NTRF by diﬀerent participants in relation to their experience. We found that 68.2% of dentists performing RCT were considered young and fell into the “10 years’ experience” or “recently graduated” groups (Table 3). Our results were in accordance with the demographics of the country, since 32% of the Saudi population is under the age of 15 and 62% of the population is between the age of 15 and 60. Furthermore, merely over 15 new dental schools have been established in the last 10 years. When we monitored the eﬀect of years of experience on the usage of NTRF, we found that there was a signiﬁcant reduction in the use of NTRF between 1991 and 2000 and