Comparison of surface roughness of CAD/CAM hybrid ceramic crown restorations after milling and mechanical polishing

Abstract

Aim: The aim of this study was to compare the surface roughness of crowns fabricated from two different hybrid blocks after milling and mechanical polishing. Method: Twenty-six single crowns were milled from two different CAD/CAM hybrid blocks (nano-ceramic: NC and polymer-infiltrated ceramic: PIC) by using the same STL data (n= 13). Surface roughness (Ra) values of crowns were measured via profilometer at baseline. Then, all crowns were polished with a two-step polishing set and a diamond paste. After mechanical polishing, surface roughness (Ra) values were obtained by a profilometer. The statistical analysis of the data was performed by Student’s and paired t-tests (α= 0.05). Results: The baseline mean Ra values for NC and PIC crowns were 0.86 and 1 µm, respectively, and were not statistically different (p > 0.05). After mechanical polishing, the average Ra values of both groups decreased significantly and were obtained as 0.29 for NC group and 0.3 for PIC group (p < 0.05). There was no statistically significant difference between the mean Ra values of PIC and NC after polishing (p > 0.05). Conclusion: The surface roughness values of the crowns milled from CAD/CAM hybrid blocks did not differed according to the hybrid block type used. However, after the mechanical polishing, the surface roughness of both CAD/CAM hybrid crowns decreased compared to the baseline. Clinicians can reduce the surface roughness of the crowns fabricated from hybrid blocks by using mechanical polishing.

Keywords

• CAD/CAM
• Dental crown
• polishing
• Prosthodontics
• Surface properties

CAD/CAM hibrit seramik kron restorasyonlarının kazıma ve mekanik bitim-parlatma işlemi sonrası yüzey pürüzlülüklerinin karşılaştırılması

Abstract

Amaç: Bu çalışmanın amacı iki farklı CAD/CAM hibrit bloktan kazınarak elde edilen kronların freze sonrası başlangıç ve mekanik bitim-parlatma işlemi sonrası yüzey pürüzlülüklerinin karşılaştırılmasıdır. Yöntem: Yirmi altı adet kron aynı STL data kullanılarak, iki farklı CAD/CAM hibrit bloktan (nano-seramik: NS ve polimer-infiltre seramik: PIS) kazınarak elde edildi (n= 13). Kronların başlangıç (freze sonrası) yüzey pürüzlülük (Ra) değerleri profilometre cihazı ile ölçüldü. Ardından tüm kronlar, iki aşamalı polisaj lastik seti ve elmas dolduruculu pat ile parlatıldı. Mekanik bitim-parlatma işlemi sonrası pürüzlülük değerleri yine profilometre cihazı kullanılarak elde edildi. Her gruptan birer örnek yüzey görüntüleme analizi için taramalı elektron mikroskobu ile incelendi. Elde edilen verilerin istatistiksel analizi Student’s ve eşleştirilmiş t-testleri kullanılarak yapıldı (α= 0.05). Bulgular: NS ve PIS kronların başlangıç ortalama Ra değerleri sırasıyla 0.86 ve 1 µm olarak elde edilmiş olup aralarında istatistiksel olarak anlamlı bir fark bulunmadı (p > 0.05). Mekanik bitim-parlatma işlemi sonrası her iki grubun ortalama Ra değeri anlamlı derecede düşüş gösterdi ve NS grubu için 0.29 PIS grubu için ise O.3 olarak elde edildi (p < 0.05). Bitim-parlatma işlemi sonrası PIS ve NS grupları için elde edilen ortalama Ra değerleri arasında istatistiksel açıdan anlamlı bir fark tespit edilmedi (p > 0.05). Sonuç: CAD/CAM hibrit bloklardan kazınan kronların yüzey pürüzlülük değerleri hibrit bloğun çeşidine göre farklılık göstermemiştir. Buna karşın her iki CAD/CAM hibrit kronun mekanik bitim-parlatma işlemi sonrası yüzey pürüzlülüğü freze sonrası başlangıç durumuna göre azalmıştır. Klinisyenlerin mekanik bitim-parlatma işlemi ile hibrit bloklardan elde edilen kronların yüzey pürüzlülüklerini azaltması mümkündür.

Keywords

• Dental kron
• Polisaj
• Prostodonti
• Yüzey özellikleri
• CAD/CAM

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