Root canal instrumentation has evolved significantly with the advent of engine-driven nickel–titanium (NiTi) rotary instruments, which offer superior flexibility and fatigue resistance compared with traditional stainless steel files. NiTi alloys exhibit superelasticity and shape memory, allowing intricate negotiation of curved canals with reduced risk of procedural errors such as ledging and canal transportation. This mechanical advantage has made rotary NiTi files the standard for contemporary endodontic shaping. [1–3] The diversity of rotary NiTi systems on the market — with varying metallurgy, heat treatments, cross-sectional designs, and motion kinematics — has complicated instrument selection. Critical properties such as cutting efficiency, cyclic fatigue resistance, and handling characteristics differ between systems; thus, clinicians must integrate knowledge of instrumentation mechanics with clinical judgment. For example, heat-treated instruments (e.g., CM wire, EDM-processed files) demonstrate enhanced cyclic fatigue resistance compared with conventional NiTi files, theoretically improving fracture resistance during clinical use. [4–6] Despite widespread adoption, the clinical decision-making process regarding rotary file selection varies across practitioners. Surveys on rotary instrument usage have historically focused on adoption rates and incidence of file fracture rather than comprehensive KAP frameworks. A Tehran-based study reported high adoption of NiTi rotary instruments among endodontists, with procedural problems primarily attributed to over-use and excessive pressure during instrumentation. [7] Similarly, research in India noted variation in usage patterns and reliance on personal experience in rotary system choice. [8] These findings suggest clinician preferences may be influenced more by training and habit than standardized evidence on instrument performance. The knowledge–attitude–practice (KAP) model — widely used in health research — provides a systematic approach to assess what clinicians know about a subject, how they feel about it, and how they behave. KAP studies help identify knowledge gaps, potential misconceptions, and barriers to best practice, and have been applied in dental research to topics like antibiotic prescribing and apex locator use. [9,10] However, there is a notable gap in current literature specifically assessing endodontists’ KAP toward selection of rotary file systems, particularly within high-volume endodontic environments such as India. Understanding clinicians’ knowledge base regarding NiTi instrument characteristics, their attitudes toward performance and safety, and actual selection practices is crucial for several reasons. First, it can highlight areas where continuing education could improve evidence-based instrument choice. Second, it may inform manufacturers about clinical priorities, potentially guiding future innovations. Third, it enables comparison of preferences across demographic strata — for instance, between academic clinicians and private practitioners. Given the lack of contemporary data, this study was designed to survey Indian endodontists to quantify and analyze KAP regarding rotary file selection, exploring associations with demographic and practice variables.

Study Design and Setting This cross-sectional survey was conducted among licensed endodontists practicing in India. The study protocol was reviewed and approved by an institutional ethics committee, and informed consent was implied through voluntary participation. Questionnaire Development The survey instrument was designed after a comprehensive literature review of rotary NiTi systems and clinician practices. Items were adapted from previously published usage surveys and refined for KAP evaluation. Face and content validity were assessed by a panel of three endodontic educators and a dental research methodologist. A pilot test with 20 endodontists evaluated clarity and reliability; modifications were made based on feedback. Survey Instrument and Domains The final questionnaire comprised four sections: 1. Demographics: Age, gender, years of practice, primary practice setting (academic, private, hospital). 2. Knowledge: Objective questions on instrument metallurgy, motion types (continuous rotation, reciprocation), cyclic fatigue, and fracture resistance. 3. Attitude: Likert-scale items assessing importance of criteria such as cutting efficiency, fracture resistance, cost, and manufacturer support in selecting a rotary system. 4. Practice: Self-reported frequency of different systems used (ProTaper, WaveOne, HyFlex, etc.), reuse protocols, irrigation protocols concurrent with instrumentation, and management of instrument separation scenarios. Sample and Recruitment A convenience sampling approach targeted endodontists through professional associations, dental conferences, and electronic mailing lists. Inclusion criteria were: certified endodontic specialists with active clinical practice in India. Exclusion criteria included incomplete responses and non-endodontist respondents. Data Collection and Scoring Responses were collected electronically via a secure platform. Knowledge scores were calculated as the sum of correct responses; attitude scores were averaged across Likert items; practice scores were frequency-based metrics for usage patterns. Statistical Analysis Data were exported to SPSS v28 (IBM Corp., Armonk, NY). Descriptive statistics summarized participant characteristics and KAP domains. Comparisons between demographic subgroups utilized chi-square tests for categorical variables and ANOVA for continuous scores. Logistic regression models analyzed predictors of high knowledge and practice adoption (p<0.05 considered significant).

A total of 312 endodontists completed the questionnaire and were included for analysis. Most respondents were from private practice, and the most common experience bracket was 6–10 years. Rotary instrumentation was used routinely by the majority of clinicians. Knowledge scores, attitude ratings, and practice patterns demonstrated statistically significant associations with years of experience and workplace setting. Table 1 summarizes participant demographics and clinical experience. The mean age of respondents was 34.8 ± 6.9 years, with a slightly higher proportion of males (55.4%) compared to females (44.6%). Private practice represented the largest group (62.8%), followed by academic institutions (25.0%) and hospital-based practice (12.2%). Most endodontists reported using rotary systems in more than 75% of cases. A statistically significant association was observed between years of experience and practice setting (p=0.021). Table 1. Demographic and practice characteristics of respondents (n=312) Variable Category n (%) Age (years) Mean ± SD 34.8 ± 6.9 Gender Male 173 (55.4) Female 139 (44.6) Practice setting Private practice 196 (62.8) Academic 78 (25.0) Hospital-based 38 (12.2) Years of experience 0–5 years 92 (29.5) 6–10 years 104 (33.3) 11–15 years 66 (21.2) >15 years 50 (16.0) Rotary use frequency <25% of cases 18 (5.8) 25–50% 44 (14.1) 51–75% 72 (23.1) >75% 178 (57.1) Association: Years of experience vs practice setting: χ²=11.6, p=0.021 Table 2 presents knowledge responses regarding rotary file metallurgy, fatigue resistance, and motion kinematics. A high proportion correctly identified cyclic fatigue as a key determinant of separation in curved canals (78.8%). Knowledge regarding heat-treated alloys and their clinical advantage was correct in 71.5%. However, misconceptions were observed regarding single-file systems and apical extrusion, with only 46.8% answering correctly. Overall, 61.9% achieved a “high knowledge” score (≥70%). Knowledge scores were significantly higher among academic clinicians (p=0.008). Table 2. Knowledge assessment regarding rotary file systems (n=312) Knowledge item Correct response n (%) correct Cyclic fatigue is a major cause of NiTi separation in curved canals Yes 246 (78.8) Heat-treated NiTi improves flexibility and fatigue resistance Yes 223 (71.5) Reciprocating motion reduces torsional stress compared with continuous rotation Yes 201 (64.4) Glide path creation reduces risk of instrument fracture Yes 269 (86.2) Excessive reuse increases separation risk Yes 288 (92.3) Single-file shaping always produces less debris extrusion than multi-file systems No 146 (46.8) High knowledge score (≥70%) — 193 (61.9) Comparison: High knowledge score by setting • Academic: 56/78 (71.8%) • Private: 115/196 (58.7%) • Hospital: 22/38 (57.9%) χ²=9.7, p=0.008 Table 3 demonstrates attitude patterns influencing rotary system selection. Fracture resistance and cyclic fatigue performance were rated as “very important” by 83.0%, while shaping efficiency was prioritized by 79.2%. Cost was a major deciding factor for 61.5%, especially among private practitioners. Notably, only 42.6% strongly agreed that manufacturer claims should be trusted without independent evidence. Endodontists with >15 years of experience were significantly more likely to prioritize tactile handling and system familiarity (p=0.014). Table 3. Attitude toward selection criteria for rotary file systems (n=312) Selection criterion Strongly agree / Very important n (%) Cyclic fatigue resistance / fracture safety 259 (83.0) Shaping efficiency / speed 247 (79.2) Preservation of canal anatomy 236 (75.6) Cost-effectiveness 192 (61.5) Availability of system locally 207 (66.3) Training and familiarity with the system 221 (70.8) Trust manufacturer claims without independent evidence 133 (42.6) Association: Experience (>15 yrs) vs “system familiarity most important” • 15 yrs: 41/50 (82.0%) • ≤15 yrs: 180/262 (68.7%) χ²=6.1, p=0.014 Table 4 reports real-world practice patterns in rotary file system usage, reuse protocols, and fracture management. The most frequently used systems were ProTaper Gold (41.0%) and WaveOne Gold (32.7%). Most endodontists reused rotary instruments, with 54.8% reporting reuse up to 3 canals per file set. Only 28.5% reported strict single-use protocols. Instrument separation had been experienced by 63.5%, but only 35.9% routinely documented separation formally. Reuse frequency was significantly associated with practice setting (p<0.001). Table 4. Practice patterns related to rotary system use (n=312) Practice variable Category n (%) Most used rotary system ProTaper Gold 128 (41.0) WaveOne Gold 102 (32.7) HyFlex CM/EDM 34 (10.9) Reciproc Blue 26 (8.3) Others 22 (7.1) Reuse protocol Single-use only 89 (28.5) Reuse ≤3 canals 171 (54.8) Reuse >3 canals 52 (16.7) Separation experience Yes (ever) 198 (63.5) No 114 (36.5) Documentation of separation Always 112 (35.9) Sometimes 144 (46.2) Never 56 (17.9) Association: Reuse protocol vs practice setting χ²=24.8, p<0.001

The present survey evaluated knowledge, attitudes, and practice behaviours of endodontists in India regarding rotary file system selection. The results indicate that rotary instrumentation is widely integrated into routine clinical endodontics, with more than half of respondents using rotary systems in over 75% of cases. This finding aligns with previous surveys showing high adoption of NiTi rotary systems among specialist clinicians, driven by efficiency, shaping predictability, and reduced operator fatigue. [9] A key finding was that although general awareness regarding cyclic fatigue and instrument separation was high, gaps persisted in nuanced understanding of metallurgy and motion-related outcomes. Cyclic fatigue is widely recognized as a major contributor to fracture, particularly in curved canals where repetitive tension–compression cycles accumulate within the NiTi alloy. [10] In contemporary endodontics, heat-treated alloys (e.g., gold-wire, blue-wire, CM-wire) are promoted due to enhanced flexibility and improved fatigue resistance compared with conventional NiTi. [11] The current survey observed that approximately 70% correctly recognized this advantage, indicating acceptable baseline knowledge; however, the remaining proportion represents a clinically important group at risk of selecting systems without understanding their biomechanical limitations. Another notable observation was the misconception surrounding single-file systems and apical extrusion. The literature demonstrates that apical extrusion of debris is multifactorial, influenced by motion kinematics, taper, irrigation protocol, and canal anatomy, rather than being inherently minimized by single-file shaping alone. [12] This misconception has implications for postoperative pain, flare-ups, and patient satisfaction. Furthermore, studies have shown that reciprocating motion may reduce torsional stress and instrument fatigue accumulation compared with continuous rotation, though clinical superiority is not universal and depends on system design. [13] In the present survey, approximately two-thirds correctly recognized the mechanical rationale of reciprocation, suggesting moderate knowledge penetration. Attitude results demonstrated that fracture resistance, cyclic fatigue performance, and shaping efficiency were dominant selection priorities. These preferences are supported by experimental literature where cyclic fatigue resistance and torsional resistance are considered central parameters for system safety. [14] At the same time, cost-effectiveness was rated highly, especially among private practitioners. This is clinically realistic in India where the economics of endodontic care may drive reuse patterns and system choice. While cost sensitivity is expected, the high prevalence of file reuse beyond recommended thresholds is concerning, as instrument fatigue and microcrack propagation increase significantly with repeated clinical use. [15] Practice data showed ProTaper Gold and WaveOne Gold as the most commonly used systems. This is consistent with global trends where widely marketed systems with strong educational exposure dominate clinical adoption. [16] Importantly, only 28.5% followed strict single-use protocols. While strict single-use is recommended by many manufacturers, in real-world clinical environments reuse remains common. Evidence suggests that reuse increases risk of separation, particularly when canals are severely curved, when glide path is inadequate, or when clinicians apply excessive apical pressure. [17] The high percentage of respondents reporting previous instrument separation (63.5%) supports the clinical reality that separation remains frequent even among specialists. The association between academic practice and higher knowledge scores is expected. Academic endodontists may have greater exposure to recent literature, training programs, and instrument testing evidence. [18] Conversely, private practitioners may rely more on experience-based decision-making and manufacturer workshops. This highlights the need for structured continuing dental education emphasizing evidence-based selection and safe reuse protocols. An additional critical finding was the relatively low proportion of clinicians who routinely documented instrument separation. Documentation is important for medico-legal safety, referral decisions, and quality improvement. Guidelines emphasize transparency with patients and systematic documentation of procedural complications. [19] Failure to document may reflect time constraints, lack of standardized protocols, or fear of litigation, but ultimately weakens clinical accountability. Overall, the survey underscores that while adoption of rotary systems is high, selection practices are shaped by a blend of knowledge, economic factors, and system familiarity. Educational interventions should prioritize metallurgy concepts, fatigue resistance, and evidence-based reuse limits. Manufacturers and professional associations can contribute by promoting training that is not solely marketing-driven but aligned with independent research. [20-25] Future studies should consider longitudinal monitoring of practice patterns and include general dentists, as rotary systems are increasingly used outside specialist endodontics.

This nationwide survey demonstrates that rotary NiTi instrumentation is widely used among endodontists in India, with ProTaper Gold and WaveOne Gold being the most frequently preferred systems. Most clinicians showed satisfactory knowledge regarding cyclic fatigue and the importance of glide path preparation, and attitudes strongly prioritized fracture resistance, shaping efficiency, and canal anatomy preservation. However, clinically relevant knowledge gaps were identified regarding metallurgy-based performance and misconceptions related to single-file systems. Reuse of rotary instruments was common, and instrument separation was frequently experienced, yet systematic documentation was inconsistent. Practice setting and years of experience significantly influenced both knowledge and selection behaviour. These findings highlight the need for structured evidence-based continuing education, improved clinical protocols for safe reuse, and standardized documentation practices to enhance patient safety and optimize rotary system selection in endodontic practice.

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