Beyond the Curve: Evaluating Performance and Integrity of Modern NiTi Systems Under Repeated Use

Öz

Aim: In endodontic treatment, nickel-titanium (NiTi) instruments, revolutionized root canal instrumentation owing to their superior flexibility, resistance to torsional fatigue, and shape memory. Among contemporary NiTi systems, ProTaper Ultimate (PU) (Dentsply Sirona, Ballaigues, Switzerland) and Fanta AF Rising (AF-R) (Fanta Dental, Shanghai, China) are widely utilized, yet differ consid-erably in terms of their metallurgical composition, design, and clinical performance. Although both systems are commonly used in clinical practice, there is a paucity of comparative data evaluating their canal centering ability, apical transportation, post-sterilization performance, and structural integrity after multiple uses. This study aimed to compare the shaping performance, apical transportation, and structural integrity of two thermally treated NiTi rotary file systems (AF-R and PU) after repeated use and sterilization cycles in standardized simulated curved canals. Material and Methods: Sixty standardized resin blocks with 45° curvature were prepared using either AF-R or PU instruments. Each group was divided into 3 subgroups based on the number of uses and sterilizations (1st, 2nd, and 3rd cycle). Canal centering and transportation were evaluated at 5 reference levels using high-resolution digital overlays and ImageJ software. File deformation and separation were assessed under stereomicroscopy. Statistical analysis was performed using the Kruskal–Wallis and Bonferroni tests, with P < 0.05 considered statistically significant. Results: AF-R demonstrated significantly superior canal centering (P = 0.008) and lower apical transportation (P = 0.004) across all refer- ence levels and usage cycles. No file separations occurred in the AF-R group, whereas PU exhibited progressive deformation and a 6.7% separation rate by the third cycle. AF-R instruments retained their original shape and mechanical behavior after autoclave sterilization. Conclusion: AF-R exhibited enhanced shaping precision, structural durability, and resistance to apical transportation compared to PU, especially after multiple clinical uses and sterilization. These findings support its suitability for minimally invasive and cost-effec- tive endodontic practice, particularly in anatomically complex canals.

Anahtar Kelimeler

• Fanta AF Rising
• ProTaper Ultimate
• NiTi rotary files
• canal centering
• apical transportation

Kanal Eğiminin Ötesinde: Tekrarlanan Kullanımda Modern NiTi Sistemlerinin Performans ve Yapısal Bütünlüğünün Değerlendirilmesi

Öz

Giriş: Endodontik tedavide nikel-titanyum (NiTi) aletler, üstün esneklikleri, torsiyonel yorgunluğuna karşı dirençleri ve şekil hafızaları sayesinde döner kanal aletlerinde devrim yaratmıştır. Çağdaş NiTi sistemleri arasında ProTaper Ultimate (PU) (Dentsply Sirona, Ballaigues, İsviçre) ve Fanta AF Rising (Fanta Dental, Şanghay, Çin) yaygın olarak kullanılmaktadır, ancak metalurjik bileşimleri, tasarımları ve klinik performansları açısından önemli ölçüde farklılık göstermektedir. Her iki sistem de klinik uygulamada yaygın olarak kullanılmasına rağmen, kanal merkezleme yeteneklerini, apikal transportasyonunu, sterilizasyon sonrası performanslarını ve birden fazla kullanımdan sonra yapısal bütünlüklerini değerlendiren karşılaştırmalı veri eksikliği bulunmaktadır. Bu çalışma, iki farklı ısıl işlemden geçirilmiş NiTi döner alet sisteminin (Fanta AF Rising ve PU) standart eğimli, yapay kök kanallarına sahip, rezin şekillendirme blokları üzerindeki performansını, yarattığı apikal transportasyonu ve kullanım sonsı aletlerin yapısal bütünlüğünü karşılaştırmayı amaçlamaktadır. Metodoloji: Fanta AF Rising veya PU kullanılarak, rezin blokaki standart ve 45° eğrime sahip 60 adet yapay kanal boşlukları şekillendirildi. Her grup, kullanım ve sterilizasyon sayısına (1., 2. ve 3. döngü) göre üç alt gruba ayrıldı. Kanal merkezleme ve transportasyon, yüksek çözünürlüklü dijital katmanlar ve ImageJ yazılımı kullanılarak beş referans noktasından değerlendirildi. Enstrümanların deformasyonu ve ayrılması stereomikroskop ile değerlendirildi. Veriler, Kruskal-Wallis ve Bonferroni testleri kullanılarak istatistiksel olarak değerlendirildi (p <0,05). Bulgular: Fanta AF Rising, tüm referans seviyelerinde ve tüm kullanım döngülerinde önemli daha üstün kanal merkezleme ve daha düşük apikal transportasyon göstermiştir (p <0,05). Rising grubunda enstrüman ayrılması meydana gelmezken, PU’da üçüncü döngüye kadar kademeli deformasyon ve %6,7'lik bir ayrılma oranı görülmüştür. Rising’in, otoklav sterilizasyonundan sonra orijinal şekilini ve mekanik davranışlarını koruduğu görülmüştür. Sonuç: Fanta AF Rising, PU ile karşılaştırıldığında özellikle birden fazla klinik kullanım ve sterilizasyondan sonra; gelişmiş şekillendirme hassasiyeti, yapısal dayanıklılık ve apikal transportasyona karşı direnç göstermiştir. Bu bulgular, özellikle karmaşık anatomiye sahip kanallarda minimal invaziv şekillendirme için uygunluğunu desteklemektedir.

Anahtar Kelimeler

• Fanta AF Rising
• ProTaper Ultimate
• NiTi rotary files
• canal centering
• apical transportation

Kaynakça

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