Endokronların biyomekanik açıdan incelenmesi
Küçük Resim Yok
Tarih
2015
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Ege Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Diş hekimliği teknolojisi ve dental materyallerindeki gelişmelerle makroretantif tasarımlara gerek duyulmadan adeziv restorasyonlar yapılabilmektedir. Endodontik tedavili dişlerde meydana gelen aşırı doku kaybı nedeniyle geriye kalan destek dokular mümkün olduğunca korunmalıdır. Bilgisayar-destekli-tasarım/bilgisayar-destekli-üretim (CAD/CAM) sistemleriyle post ve kronun monoblok olarak hazırlandığı endokron restorasyonlar farklı materyallerden üretilebilmektedir. Çalışmamızda, prepare diş üzerine farklı rezin simanlarla simante edilen CAD/CAM endokronlara çekme bağlanma dayanım testi uygulandı. Üç farklı materyalden üretilen endokronların stres dağılımları üç boyutlu sonlu elemanlar analizi (SEA) ile değerlendirildi ve farklı solüsyonlarda bu materyallerin renk değişimleri analiz edildi. Maksiller santral dişler (N=120) 12 gruba (n=10) ayrıldı ve kanal tedavileri yapıldı. Endokronlar CAD/CAM sistemleriyle feldspatik seramik (S), monolitik zirkonya (Z) ve rezin nano seramik (RNS) materyallerinden üretildi, Superbond (SB), Variolink II (V), Panavia SA Cement (SA) ve Esthetic Cement (ES) ile simante edildi. Isıl döngü (5000 ısıl döngü, 5/55?C) işlemi sonrasında Universal Test Cihazı ile (0.5 mm/dk) ayrılma oluşuna kadar çekme testi yapıldı ve çekme bağ dayanımı değerleri (ÇBDD) kaydedildi. ÇBDD iki yönlü varyans analizi ile istatiksel olarak değerlendirildi. S grubunda, siman grupları arasında anlamlı fark bulunmadı (p=0.025). Z grubunda SB ile olan bağ dayanımı, ES grubundan anlamlı derecede yüksek bulundu (P=0.01). RNS grubunda SA ile olan bağ dayanımı, diğer siman gruplarından anlamlı derecede düşük (p<0.05) iken V, SB ve ES gruplarında anlamlı fark bulunmadı (p<0.05). SEA için, üç boyutlu maksiller-santral-diş ve S, Z ve RNS CAD/CAM endokronun SE modeli mikro-bilgisayarlı tomografi cihazı ile oluşturuldu. Dişin palatinal yüzeyinden 1350 açıyla 300N kuvvet uygulandı. Çekme ve basma kuvvetleri değerlendirildi. Sayısal veriler renk grafiklerine dönüştürüldü. Fonksiyonel kuvvet altında, tüm gruplarda stres dağılımı görüldü. Basma gerilmeleri bukkal servikal, çekme gerilmeleri palatinal servikal bölgede gözlendi. Materyal farklılıklarının, oluşan stres tiplerini ve dağılımlarını etkilediği görüldü. Yüksek elastiklik modülüsüne sahip materyaller, geniş stres birikim alanları yaratırken, düşük elastiklik modülüsüne sahip materyallerin diş dokularında lokalize ve dar alanda stres birikimleri oluşturduğu gözlendi. Renk analizi için, CAD/CAM materyallerinden elde edilen örnekler (15mmx1mm) (N=90) (ISO 7491:2000), 9 gruba (n=10) ayrıldı. S, Z ve RNS örnekleri ilk ölçümleri yapıldıktan sonra kahve, kola ve distile su solüsyonlarında 37°C±1°C'de 30 gün boyunca bekletildi. Renk değişimleri 7., 15. ve 30. günlerde ölçüldü. Verilerin iki yönlü varyans analizi (p<0.005) ve post hoc Tukey testleri ile istatiksel olarak değerlendirmeleri yapıldı. Tüm restoratif CAD/CAM materyallerinin, solüsyonlarda renk değişimi gösterdiği. S grubunun kola solüsyonunda diğer gruplara göre anlamlı derecede yüksek ?E değerlerine sahip olduğu belirlendi (p<0,001). Kola solusyonu restoratif materyallerin tümünde renklenmeye neden oldu (p<0,01). Tüm test materyallerinde, RNS en fazla renklenen grup olurken Z en az renk değişimine uğrayan gruptur. Çalışmamızın tüm sonuçları göz önüne alındığında, endokron restorasyonları için en uygun materyal olarak, diş ile olan bağlanma başarısı ve fonksiyonel kuvvetler karşısında daha az stres birikimi oluşturması nedeniyle rezin nano seramikler düşünülmektedir. Ancak bu materyalin renk değişim miktarının kabul edilebilir sınırların üzerinde olması estetik özellikleri daha da geliştirilmiş materyallere olan gereksinimi devam ettirmektedir. Endokronların simantasyonunda önerilecek en uygun simanın, yüksek bağlanma başarısı nedeniyle Superbond olduğu düşünülmektedir
With the development of adhesive techniques and dental materials the advantage of adhesive restorations is that macroretentive design is no longer a prerequisite. Endodontically treated teeth usually present inadequate remaining coronal structure so the quality and integrity of the remaining tooth must be preserved with caution. In particular, the computer-aided-design/computer-aided-manufacturing (CAD/CAM) endocrown can be built from a single block of different materials including a radicular portion and a crown. In this study, tensile bond strengths of luted CAD/CAM endocrowns with different resin cements on dentin abutments was tested. Stress distribution patterns of endocrowns with three different restorative materials assessed by three-dimensional Finite-Element-Analysis (FEA) and the impact of different storage solutions on the color stability of these materials were analyzed. Human maxillary central teeth (N = 120) divided into 12 groups (n = 10). were endodontically treated. Endocrowns produced from feldspathic ceramic (S), monolithic zirconia (Z) and resin nano ceramic (RNS) blocks utilizing a CAD-CAM unit. Endocrowns were luted with Superbond (SB), Variolink II (V), Panavia SA Cement(SA) and Esthetic Cement (ES). after aging (5000 thermal cycles, 5/55?C), endocrowns were pulled in a Universal Testing Machine (0.5 mm/min) until failure and tensile-bond-strength (TBS) was calculated. Failure types were evaluated. TBS values were analyzed using two-way ANOVA. There were no significant differences between cement groups (p=0.025) for S. SB had a significantly higher bond strength than ES (p=0.01) in Z group. SA showed lower bond strength than other cement groups (p<0.05) and there were no significant differences between V, SB and ES in RNS. For FEA, three-dimensional maxillary-central-incisor FE model was created by Micro CT scanning and S, Z and RNS CAD/CAM endocrown-restorations were designed. Incisal force of 300 N was applied from palatal surface of the crown at 1350.Results were presented, as tensile and compressive stresses. Calculated numeric data were transformed into color graphics. Stress distributions revealed in all groups that with applied functional load, compressive stresses were generated in buccal cervical region while tensile stresses were seen in palatal cervical region. Material difference caused an effective change in generated stress type and quantity. In materials with high modulus of elasticity, extensive stress concentrations were observed, while in materials with lower modulus of elasticity stress distributions in dental structures were more localized. For color analysis, samples (15mmx1mm) (N=90) (ISO 7491:2000), divided into nine groups (n=10), were made using CAD-CAM materials. After initial measurement S, Z and RNS samples were immersed in coffee, coke and distilled water as the control group for 30 days and stored at 37°C±1°C. Discoloration was measured using a spectrophotometer after 7, 15 and 30 days of storage. Data was statistically analyzed by two-way ANOVA (p < 0.05) and post hoc Tukey tests. All restorative CAD/CAM materials, discolored over time when stored in the staining solutions. S showed significantly higher ?E values in coke compared to other groups. (p<0,001). Coke produced significiant discolorations in all restorative materials (p<0,01). Among the tested materials, RNS was the material prone to discoloration most, (p<0,001) while Z showed the least color changes. (p<0.05). Within the limitations of our in-vitro study it can be concluded that the most suitable material for endocrown restorations is resin-nano-ceramics attributable to generating less stress against the functional forces and bond strength success. Nevertheless due to its unacceptable color stability, further materials are needed with improved aesthetic features. In addition the adhesive cement to be recommended for endocrown cementation is Superbond with its high bond strength values.
With the development of adhesive techniques and dental materials the advantage of adhesive restorations is that macroretentive design is no longer a prerequisite. Endodontically treated teeth usually present inadequate remaining coronal structure so the quality and integrity of the remaining tooth must be preserved with caution. In particular, the computer-aided-design/computer-aided-manufacturing (CAD/CAM) endocrown can be built from a single block of different materials including a radicular portion and a crown. In this study, tensile bond strengths of luted CAD/CAM endocrowns with different resin cements on dentin abutments was tested. Stress distribution patterns of endocrowns with three different restorative materials assessed by three-dimensional Finite-Element-Analysis (FEA) and the impact of different storage solutions on the color stability of these materials were analyzed. Human maxillary central teeth (N = 120) divided into 12 groups (n = 10). were endodontically treated. Endocrowns produced from feldspathic ceramic (S), monolithic zirconia (Z) and resin nano ceramic (RNS) blocks utilizing a CAD-CAM unit. Endocrowns were luted with Superbond (SB), Variolink II (V), Panavia SA Cement(SA) and Esthetic Cement (ES). after aging (5000 thermal cycles, 5/55?C), endocrowns were pulled in a Universal Testing Machine (0.5 mm/min) until failure and tensile-bond-strength (TBS) was calculated. Failure types were evaluated. TBS values were analyzed using two-way ANOVA. There were no significant differences between cement groups (p=0.025) for S. SB had a significantly higher bond strength than ES (p=0.01) in Z group. SA showed lower bond strength than other cement groups (p<0.05) and there were no significant differences between V, SB and ES in RNS. For FEA, three-dimensional maxillary-central-incisor FE model was created by Micro CT scanning and S, Z and RNS CAD/CAM endocrown-restorations were designed. Incisal force of 300 N was applied from palatal surface of the crown at 1350.Results were presented, as tensile and compressive stresses. Calculated numeric data were transformed into color graphics. Stress distributions revealed in all groups that with applied functional load, compressive stresses were generated in buccal cervical region while tensile stresses were seen in palatal cervical region. Material difference caused an effective change in generated stress type and quantity. In materials with high modulus of elasticity, extensive stress concentrations were observed, while in materials with lower modulus of elasticity stress distributions in dental structures were more localized. For color analysis, samples (15mmx1mm) (N=90) (ISO 7491:2000), divided into nine groups (n=10), were made using CAD-CAM materials. After initial measurement S, Z and RNS samples were immersed in coffee, coke and distilled water as the control group for 30 days and stored at 37°C±1°C. Discoloration was measured using a spectrophotometer after 7, 15 and 30 days of storage. Data was statistically analyzed by two-way ANOVA (p < 0.05) and post hoc Tukey tests. All restorative CAD/CAM materials, discolored over time when stored in the staining solutions. S showed significantly higher ?E values in coke compared to other groups. (p<0,001). Coke produced significiant discolorations in all restorative materials (p<0,01). Among the tested materials, RNS was the material prone to discoloration most, (p<0,001) while Z showed the least color changes. (p<0.05). Within the limitations of our in-vitro study it can be concluded that the most suitable material for endocrown restorations is resin-nano-ceramics attributable to generating less stress against the functional forces and bond strength success. Nevertheless due to its unacceptable color stability, further materials are needed with improved aesthetic features. In addition the adhesive cement to be recommended for endocrown cementation is Superbond with its high bond strength values.
Açıklama
Anahtar Kelimeler
Diş Hekimliği, Dentistry
