Biomechanical Comparison of Two Types of Compression Screws Using Finite Element Analysis and Servo-Hydraulic Testing Unit: an ex vitro study.

Abstract

Objectives: Various types of fixation systems have been developed to stabilize the fractured fragments in their original position. The purpose of this ex vitro study was to compare the biomechanical properties of 2 fixation units provided by different types of second-generation headless cannulated compression screws (SG-HCCS) using a servo-hydraulic testing unit (STU) and finite element analysis (FEA). Materials and Methods: 14 fresh frozen sheep cadaveric mandibles were divided into 2 groups randomly(n=7). 3.0 milimeters (mm) diameter, 20mm length partially threaded Herbert screws were used in Group 1 and 2.8mm diameter, 20mm length fully threaded HCCS were used in Group 2 for the fixation of the fragments that was made by a vertical osteotomy at the midline. 2 screws were placed in each model, parallel to each other but in opposite directions. All models were examined biomechanically for the stability of fixation by using STU and FEA. Results: Both FEA and STU analysis revealed that the forces required to fail the fixation system provided by HCCS were significantly higher than Herbert screws. Conclusions: Within the limits of this experimental study, the findings suggest that the biomechanical adequacy provided by second-generation compression screws may be a promising alternative in the treatment of mandibular symphysis fractures, aided by the favorable anatomy of the region. The study may also be useful for further studies in terms of evaluating and comparing different fixation systems in virtual environments using FEA.

Keywords

• Bone screws
• compression
• finite element analysis
• fracture fixation
• mandible

Mandibular Simfiz Fraktürlerinde Kullanılan İki Farklı Kompresyon Vidasının Biyomekanik Özelliklerinin Sonlu Elemanlar Analizi ve Servohidrolik Test Ünitesi ile Değerlendirilmesi ve Karşılaştırması: ex vitro bir çalışma.

Abstract

Amaç: Kırık parçaları orijinal pozisyonlarında sabitlemek için çeşitli fiksasyon sistemleri geliştirilmiştir. Bu ex vitro çalışmanın amacı, bir servohidrolik test ünitesi (STU) ve sonlu elemanlar analizi (SEA) kullanılarak 2 farklı tasarıma sahip ikinci nesil başsız kanüllü kompresyon vidaları kullanılarak oluşturulan fiksasyonun biyomekanik özelliklerini karşılaştırmaktı. Gereç ve Yöntemler: 14 adet taze dondurulmuş koyun kadavra alt çenesi rastgele 2 gruba ayrıldı (n=7). Mandibular simfiste orta hatta vertikal osteotomi ile kırık hattı oluşturuldu. Oluşturulan kırık fragmanların fiksasyonu için Grup 1'de 3,0 mm çapında, 20 mm uzunluğunda kısmen yivli Herbert vidaları, Grup 2'de ise 2,8 mm çapında, 20 mm uzunluğunda tam yivli HCCS vidaları kullanıldı. Her modele birbirine paralel ancak zıt yönlerde 2 adet vida yerleştirildi. Tüm modeller, STU ve SEA kullanılarak fiksasyonun stabilitesi açısından biyomekanik olarak incelendi. Bulgular: Hem SEA hem de STU analizleri, HCCS kullanılarak oluşturulan fiksasyonun bozulması için gereken kuvvetlerin Herbert vidalarından istatistiksel olarak anlamlı derecede yüksek olduğu gözlemlendi. Sonuç: Bu deneysel çalışmanın sınırları dahilinde, bulgular, ikinci nesil kompresyon vidalarının sağladığı biyomekanik yeterliliğin, bölgenin uygun anatomisinin de yardımıyla mandibular simfiz kırıklarının tedavisinde umut verici bir alternatif olabileceğini düşündürmektedir. Çalışma ayrıca SEA kullanılarak sanal ortamlarda farklı sabitleme sistemlerinin değerlendirilmesi ve karşılaştırılması açısından ileriki araştırmalara da faydalı olabilir.

Keywords

• Çene kırıkları
• kırık sabitlenmesi
• mandibula
• sonlu eleman analizi

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