CYCLIC FATIGUE OF REVO-S NICKEL-TITANIUM ROTARY INSTRUMENTS IN ARTIFICIAL CANALS WITH TWO DIFFERENT RADII OF CURVATURE

Background and Aim: Rotary nickel-titanium (NiTi) instruments allow for more predictable instrumentation of curved canals with a lesser risk of transportation, ledging, and perforations than stainless-steel instruments. Nevertheless, despite all the aforementioned benefits, there is a higher risk of instrument separation with rotary NiTi instruments, specifically during the instrumentation of curved canals. To assess the resistance to cyclic fatigue of Revo-S NiTi files, artificial canals with 5mm and 10mm curvature radii were operated on. Materials and Methods: A total of 120 new Revo-S files (Micro Mega, Besancon, France) were used. Revo S of tip sizes SU, AS30, AS35, and AS40 were subjected to cyclic fatique testing in stainless-steel artificial canals with curvature radii of 5 and 10 mm until fracture occurred (n=15 for each group). The mean fragment length (MFL [in millimeters from the shaft to the fracture point]) was measured under 10x magnification with an electronic gauge to assess the location of the fracture. The number of cycles for each instrument until the time of fracture (NCF) was recorded. Statistical analysis was performed using two way ANOVA test, followed by Tukey HSD post hoc test. Results: Revo-S files were associated with a significantly higher cyclic fatique resistance at the 10-mm radius group than that of the 5-mm radius group (P < 0.001). For the 10-mm radius group, AS30 had the highest NCF, followed by AS40, AS 35 and SU. Conclusions: Cyclic fatigue resistance of Revo-S files was dependent on both the curvature radius of the canal and the instrument size.

REVO-S NİKEL-TİTANYUM DÖNER ALETLERİN İKİ FARKLI EĞRİLİK ÇAPINDAKİ DÖNGÜSEL YORGUNLUĞU

Amaç: Döner nikel titanyum (NiTi) aletler, eğri kanalların paslanmaz-çelik aletlere göre daha az transportasyon, basamak ve perforasyon riskiyle daha merkezde şekillendirilmesini sağlar. Revo-S NiTi eğelerin 5 mm ve 10 mm eğrilik çapında kullanıldığı zamanki döngüsel yorgunluğunun değerlendirilmesidir. Gereç ve Yöntemler: Toplam 120 yeni Revo-S eğesi (Micro Mega, Besancon, Fransa) kullanıldı. Revo S uç çapları SU, AS30, AS35 ve AS40, 5 ve 10mm eğrilik çapındaki paslanmaz çelik yapay kanallarda kırık olana dek döngüsel yorgunluk testine maruz bırakıldı (n=15, her bir grup için). Ortalama kırık parça uzunluğu (MFL [saptan kırılma noktasında dek milimetre cinsinde]) x10 büyütmede elektronik kumpas ile ölçülerek kırığın yeri değerlendirildi. Herbir eğe için kırık olana dek olan dönme sayısı (NCF) kaydedildi. İstatistiksel analiz two way ANOVA testi, takibinde de Tukey HSD post hoc testi kullanılarak yapıldı. Bulgular: Revo-S eğeleri 10-mm çaplı grupta 5-mm çaplı gruptan anlamlı derecede daha yüksek döngüsel yorgunluk direncine sahipti (P < 0.001). 10-mm çaplı grupta, AS30 en yüksek NCF’sini, sırasıyla AS40, AS 35 ve SU takip etmektedir. Sonuçlar: Revo-S eğelerin döngüsel yorgunluk direnci hem eğrilik çapı hem de eğe boyutuna bağlıdır.

Kaynakça

Peters OA, Morgental RD, Schulze KA, Paque F, Kopper PM, Vier-Pelisser FV. Determining cutting efficiency of nickel- titanium coronal flaring instruments used in lateral action. Int Endod J 2014; 47: 505–513.

Kazemi RB, Stenman E, Spångberg LS. A comparison of stainless steel and nickel-titanium H-type instruments of identical design: torsional and bending tests. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000; 90: 500–506.

Sattapan B, Nervo GJ, Palamara JE, Messer HH. Defects in rotary nickel‑titanium files after clinical use. J Endod 2000; 26: 161‑165.

Peters OA. Current challenges and concepts in the preparation of root canal systems: A review. J Endod 2004; 30: 559‑567.

Parashos P, Gordon I, Messer HH. Factors influencing defects of rotary nickel‑titanium endodontic instruments after clinical use. J Endod 2004; 30: 722‑725.

Pirani C, Cirulli PP, Chersoni S, Micele L, Ruggeri O, Prati C. Cyclic fatigue testing and metallographic analysis of nickel-titanium rotary instruments. J Endod 2011; 37: 1013-1016.

Pruett JP, Clement DJ, Carnes DL Jr. Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod 1997; 23: 77-85.

Pedulla E, Grande NM, Plotino G, Pappalardo A, Rapisarda E. Cyclic fatigue resistance of three different nickel-titanium instruments after immersion in sodium hypochloride. J Endod 2011; 37: 1139- 1142.

Basrani B, Roth K, Sas G, Kishen A, Peters OA. Torsional profiles of new and used Revo-S rotary instruments: An in vitro study. J Endod 2011; 37: 989-992.

Gambarini G. Cyclic fatigue of nickel-titanium rotary instruments after clinical use with low-and high-torque endodontic motors. J Endod 2001; 27: 772-774.

Cheung GSP. Instrument fracture: mechanisms, removal of fragments, and clinical outcomes. Endod Topics 2009; 16: 1–26.

Grande NM, Plotino G, Pecci R, Bedini R, Malagnino VA, Soma F. Cyclic fatigue resistance and three dimensional analysis of instruments from two nickel-titanium rotary systems. Int Endod J 2006; 39: 755-763.

Zelada G, Varela P, Martin B, Bahillo JG, Magan F, Ahn S. The effect of rotational speed and the curvature of root canals on the breakage of rotary endodontic instruments. J Endod 2002; 28: 540-542.

Inan U, Aydin C, Tunca YM. Cyclic fatigue of ProTaper rotary nickel-titanium instruments in artificial canals with 2 different radii of curvature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 104: 837-840.

Martin B, Zelada G, Varela P, Bahillo JG, Magan F, Ahn S et al. Factors influencing the fracture of nickel-titanium rotary instruments. Int Endod J 2003; 36: 262-266.

Haikel Y, Serfaty R, Bateman G, Senger B, Allemann C. Dynamic and cyclic fatigue of engine-driven rotary nickel-titanium endodontic instruments. J Endod 1999; 25: 434-440.

Gambarini G. Cyclic fatigue of Profile rotary instruments after prolonged clinical use. Int Endod J 2001; 34: 386-389.

Sattapan B, Palamara JE, Messer HH. Torque during canal instrumentation using rotary nickel–titanium files. J Endod 2000; 26: 156–160.

Yared G, Bou Dagher F, Machtou P. Cyclic fatigue of ProFile rotary instruments after clinical use. Int Endod J 2000; 33: 204- 207.

Di Fiore PM, Genov KA, Komaroff E, Li Y, Lin L. Nickel-titanium rotary instrument fracture: A clinical practice assessment. Int Endod J 2006; 39: 700-708.

Kaynak Göster