Metal-ceramic bond strength between a feldspathic porcelain and a Co-Cr alloy fabricated with Direct Metal Laser Sintering technique

Abstract

PURPOSEThe aim of the present study was to record the metal-ceramic bond strength of a feldspathic dental porcelain and a Co-Cr alloy, using the Direct Metal Laser Sintering technique (DMLS) for the fabrication of metal substrates.MATERIALS AND METHODSTen metal substrates were fabricated with powder of a dental Co-Cr alloy using DMLS technique (test group) in dimensions according to ISO 9693. Another ten substrates were fabricated with a casing dental Co-Cr alloy using classic casting technique (control group) for comparison. Another three substrates were fabricated using each technique to record the Modulus of Elasticity (E) of the used alloys. All substrates were examined to record external and internal porosity. Feldspathic porcelain was applied on the substrates. Specimens were tested using the three-point bending test. The failure mode was determined using optical and scanning electron microscopy. The statistical analysis was performed using t-test.RESULTSSubstrates prepared using DMLS technique did not show internal porosity as compared to those produced using the casting technique. The E of control and test group was 222 ± 5.13 GPa and 227 ± 3 GPa, respectively. The bond strength was 51.87 ± 7.50 MPa for test group and 54.60 ± 6.20 MPa for control group. No statistically significant differences between the two groups were recorded. The mode of failure was mainly cohesive for all specimens.CONCLUSIONSpecimens produced by the DMLS technique cover the lowest acceptable metal-ceramic bond strength of 25 MPa specified in ISO 9693 and present satisfactory bond strength for clinical use.

Effect of Bonding Agent on Metal‐Ceramic Bond Strength between Co‐Cr Fabricated with Selective Laser Melting and Dental Feldspathic Porcelain

“…After the bending tests, the fractured surfaces were inspected in order to determine the failure mode. In the case of over 50% of the fracture surface (on the alloy side) being covered with ceramic material (including bonding agent), the mode of failure was defined as cohesive, while in the case of this percentage being lower than 50% the mode of failure was defined as adhesive . Thus, the mode of failure in both groups A and B was cohesive, confirmed by an inspection with the naked eye as well as by EDS elemental analysis conducted over the fracture surface of the alloy substrates.…”

“…The characteristics and settings are detailed in Table . The SLM technique was chosen because it led to Co‐Cr substrates with a microstructure characterized by zero porosity, as compared to the casting technique, which leads to the production of metal substrates with extensive porosity …”

“…The selective laser melting (SLM) technique features high productivity, almost unlimited shaping ability, and improved internal and marginal fit. Moreover, the final products have minimal porosity and improved mechanical properties; however, the equipment required for SLM is still rather expensive, and the cost is transferred to the final product and eventually to the client/patient or to the national health‐care budget …”

Evaluation of the Bond Strength of Ceramics to Metal Alloys Obtained by Different Techniques Using by Different Testing Methods

“…geleneksel döküm ve selektif lazer ile sinterleme yöntemi ile elde ettikleri Co-Cr metal alaşım örneklerinin, üç nokta bükme testi ile porselen bağlanma dayanımını ve elastik modülünü değerlendirmiş ve çalışmamıza paralel olarak, geleneksel döküm ve selektif lazer ile sinterleme yöntemi ile elde edilen metal alaşım örneklerin porselen bağlanma dayanımı değerleri ve elastik modül değerleri arasında anlamlı bir fark olmadığını bul-muşlardır. 7 Ayrıca, her iki yöntemde de kırık modellerinin porselen içinde koheziv tipte olduğunu belirtmişlerdir. Çalışmamızdan farklı olarak ise Wang ve ark., geleneksel döküm, bilgisayar destekli milleme ve selektif lazer ile sinterleme yöntemleriyle elde edilen Co-Cr alaşımlarının metal-porselen bağlanma dayanımını üç nokta bükme testi ile değerlendirdikleri çalışmalarında, selektif lazer ile sinterleme grubunda bağlanma dayanımının daha yüksek olduğunu rapor etmişlerdir.…”

“…21 SLS yöntemi ile elde edilen metal altyapıların birçok avantajı literatürde rapor edilmesine rağmen, bu teknikle üretilen altyapıların metal-porselen bağlantısı ile ilgili yeterli çalışma mevcut değildir. 7,[22][23][24][25] Bu çalışmada, SLS ve geleneksel döküm yöntemi ile elde edilen Co-Cr alaşımlarının metal-por- SLS (n=20) ve geleneksel döküm yöntemi (n=20) ile elde edilen örnekler rastgele dağıtılarak 10'ar adet örnekten oluşan 4 alt grup oluşturul-muştur. Geleneksel döküm ve SLS ile elde edilen 10'ar örneğe üç nokta bükme testi uygulanabilmesi için, örneklerin ortasındaki 8 mm x 3 mm'lik dikdörtgen alana ISO 9693'e göre toplam 1,1 mm kalınlığında olacak şekilde, ilk olarak porselen bağlayıcı ajan (3C-Bond Ceka Preci-Line, Alphadent NV, Belçika), sonrasında ince bir tabaka opak porselen (Vita Opaque VMK Master, Almanya) ve opak porselenin üzerine gövde porseleni (Kuraray Noritake Dental Inc., ABD) uygulanmıştır.…”