Finite element analysis of stress distribution on canal walls while preparation of curved canals

Yıl 2013, Cilt: 3 Sayı: 1, 14 - 18, 29.01.2014

Dilek Erbay Türkaydın Mahir Günday Bülent Ekici

Öz

Objective: The aim of this study is to determine stress evaluation of root canal wall during shaping curved canals with ProTaper and HeroShaper systems by using three-dimensional finite element universal. 

Methods: The geometries of the ProTaper Universal and HeroShaper Ni-Ti rotary systems’ selected files were created using three-dimensional finite element modelsThe three-dimensional FEA model within a curved canal was established by integrating a simulated canal and natural tooth. A micro-focus CT scanner was used to scan the models. After integration and modification a final three-dimensional model with a smooth surface and mostly centered canal was established. The stresses on the instrument during simulated shaping of a root canal were analyzed numerically by using a three-dimensional finite element package, LS-DYNA, taking into account the nonlinear mechanical behavior of the nickel-titanium material. Stress distribution in the instruments and the canal walls was recorded during simulated shaping. 

Results: With ProTaper file system, stress concentrations were determined towards the outer aspect of the curvature in the apical portion of the canal but in HeroShaper system stress was more concentrated in the middle portion of the canal and were less than ProTaper model. 

Conclusion: HeroShaper files cut more efficiently and generated less stress on the canal walls than ProTaper files because of their possitive rake angle. It was observed that there was stress concentration towards the outer aspect of the curvature in the apical portion of the canal with the ProTaper file system. This shows us that these files are more feasible for apical transportation.

Key words: Curved canals, HeroShaper, ProTaper, finite element analysis, stress

Anahtar Kelimeler

Curved canals, HeroShaper, ProTaper, finite element analysis, stress

Eğri kök kanallarında şekillendirme sırasında oluşan streslerin sonlu elemanlar yöntemi ile değerlendirilmesi

Öz

Amaç: Bu çalışmanın amacı eğri kök kanallarında ProTaper Universal ve HeroShaper sistemleri ile şekillendirme yapılırken kanal duvarlarında oluşan streslerin üç boyutlu sonlu elemanlar analizi ile belirlenmesidir. 

Yöntem: ProTaper Universal ve HeroShaper Ni-Ti döner alet sistemlerine ait eğelerin geometrileri üç boyutlu sonlu elemanlar yöntemi ile oluşturulmuştur. Eğri kök kanalına sahip dişin üç boyutlu sonlu elemanlar modeli, doğal diş ve yapay kanalın birleştirilmesi ile oluşturulmuştur. Modellerin taranması için mikro-fokus CT kullanılmıştır. Birleştirme ve modifikasyondan sonra düzgün yüzeyli ve kanalı merkezde seyreden üç boyutlu model elde edilmiştir. Şekillendirme benzetimi sırasında kanal duvarlarında oluşan stresler LS-DYNA sonlu elemanlar programı ile ve nikel titanyum materyalinin non-lineer mekanik özellikleri dikkate alınarak kayıt edilmiştir. 

Bulgular: ProTaper eğe sistemi ile şekillendirmede kanalın apikal kısmında eğimin dışına doğru stres yoğunluğu oluştuğu ancak HeroShaper ile yapılan şekillendirme benzetiminde orta kısımda ve ProTaper modelinden daha az stres oluştuğu belirlenmiştir. 

Sonuçlar: HeroShaper eğe modelleri kanal duvarlarında ProTaper eğe modellerine göre daha az stres oluşturmuştur. HeroShaper eğe modellerinin kesme etkinliğinin yüksek olması sebebiyle dentin direnci azalmaktadır. ProTaper eğe modelleri ile şekillendirme benzetimi yapılan kanalarda stres oluşumunun, özellikle apikal alanda eğriliğin dışına doğru artmış olduğu görülmüştür. Bu da ProTaper eğelerinin apikal transportasyona daha yatkın olduğunu göstermektedir.

Anahtar Kelimeler : Eğri kök kanalları, HeroShaper, ProTaper, sonlu elemanlar analizi, stres

Anahtar Kelimeler

Eğri kök kanalları, HeroShaper, ProTaper, sonlu elemanlar analizi, stres

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