Metal-ceramic interface characteristics of Co-Cr alloy fabricated by selective laser melting / 中国组织工程研究

BACKGROUND: Co-Cr ceramic alloys made by selective laser melting technology are widely used in the field of dental restoration, but the influence of selective laser melting technology on the bonding properties of Co-Cr ceramic alloys is still controversial. OBJECTIVE: To explore the metal-ceramic interface characteristics of dental Co-Cr alloy fabricated by selective laser melting. METHODS: Metal-ceramic specimens were prepared by selective laser melting and precision casting, respectively. Metal-ceramic bond strengths, interface characteristics, fracture analysis, microstructures and composition distribution of specimens were obtained with the aid of universal testing machine, metallographic microscope, scanning electron microscope coupled with energy disperse spectrometer. RESULTS AND CONCLUSION: (1) The metal-ceramic bond strengths of precision casting Co-Cr alloy was higher than that of selective laser melting Co-Cr alloy (P < 0.05). (2) Metallographic microscope showed that selective laser melting Co-Cr alloy had fine grains and a more uniform matrix. Precision casting Co-Cr alloy showed typical casting dendritic structure with coarse grains and a large number of island second phase structures. (3) Scanning electron microscopy showed that precision casting Co-Cr alloy had a thicker diffusion layer than the selective laser melting Co-Cr alloy at the metal-ceramic interface. (4) Scanning electron microscopy showed that the metal-ceramic specimens of precision casting Co-Cr alloy tended to cohesive fracture, and the metal-ceramic specimens of selective laser melting Co-Cr alloy tended to adhesive fracture. (5) The results showed that although the bonding strength of selective laser melting Co-Cr alloy was lower than that of precision casting Co-Cr alloy, the bonding strength of selective laser melting Co-Cr alloy could still meet the requirements of standard YY0621.1-2016.

Effect of different sandblasting conditions on the metal-ceramic bonding strength of Co-Cr alloy fabricated by selective laser melting technology / 华西口腔医学杂志

OBJECTIVE@#To investigate the effect of different sandblasting conditions on the metal-ceramic bonding strength of Co-Cr alloy fabricated by selective laser melting (SLM) technology.@*METHODS@#A total of 63 specimens of Co-Cr alloy fabricated by SLM were prepared and randomly divided into nine groups (n=7). Each group was treated with different powder particles (A1=50 µm, A2=100 µm, and A3=150 µm) and pressures (B1=0.2 MPa, B2=0.4 MPa, and B3=0.6 MPa) in sandblasting. One sample was randomly selected from each group for microstructure observation by scanning electron microscope (SEM). Ceramic was fired at the center of the specimens. Metal-ceramic bonding strength was measured with universal testing machine. Results were statistically analyzed with SPSS 17.0 software.@*RESULTS@#The mean bond strengths were as follows: Group A1B1: 27.22 MPa±0.95 MPa, Group A1B2: 27.58 MPa±0.47 MPa, Group A1B3: 26.80 MPa±0.71 MPa, Group A2B1: 27.54 MPa±0.78 MPa, Group A2B2: 30.75 MPa±0.43 MPa, Group A2B3: 26.93 MPa±0.88 MPa, Group A3B1: 28.18 MPa±0.93 MPa, Group A3B2: 29.55 MPa±0.57 MPa, and Group A3B3: 28.11 MPa±0.91 MPa. The particle factor of Al₂O₃ and the pressure factor of blasting showed statistical significance (P<0.05). An interaction was observed between the factors of particle and pressure (P<0.05). Mixed fracture mode of all specimens was observed after the shear strength test.@*CONCLUSIONS@#In conclusion, metal-ceramic bonding strength reaches the maximum when specimens are sandblasted with 100 µm alumina oxide at 0.4 MPa pressure.

Effect of Different Silane Treatments on Long-Term Bonding Between Non-Etched Glass-Ceramic and Resin Cement

he present study evaluated the bond strength between glass-ceramic and resin cement, using different silane treatments, performing no previous hydrofluoric acid (HF) etching on ceramic surface, after short- and long- term storage. One hundred and eighty glass-ceramic plaques (IPS e.max CAD®) were polished and divided into six groups (n=30) to receive different silane treatments: (1) RCP-RelyX Ceramic Primer® (one-bottle silane), (2) RCP+SB-RelyX Ceramic Primer and Adper Singlebond2® (silane plus separated adhesive), (3) SBU-Scotchbond Universal® (silane-containing universal adhesive), (4) CP-Clearfil Ceramic Primer® (silane/MDP primer), (5) NC-no-silane (negative control) and (6) PC-Previous HF etching (5%, 20s) plus RelyX Ceramic Primer® (positive control). Two resin cement cylinders (Rely X Ultimate®) were built on each plaque. Each group was divided into two sub-groups to be stored for 24 hours (24h) or 6 months (6mo) in distilled water at 37°C (n=15). Then microshear (µSBS) testing was performed. Failure mode was analyzed using scanning electron microscopy (SEM). Data were statistically analyzed by two-way ANOVA and Tukey´s test (α=0.05). Both factors and their interaction resulted statistically significant (p≤0.05). PC obtained the highest µSBS values (in MPa) at both storage times (24h: 28.11±2.44; 6mo: 19.10±3.85). After 24h storage, groups RCP+SB (10.86±3.62), SBU (8.37±4.33) and CP (8.05±3.62) were not statistically different from NC (8.00±2.51); only RCP (19.73±4.63) and PC obtained higher values. After 6 months, only PC showed higher values than NC (0.04±0.01). Cohesive failure in resin cement was more prevalent for RCP-24h and PC, while adhesive failure was more frequent among all other groups. Clinical relevance: None of the commercially available silane primers tested, improve long- term ceramic/cement bonding without performing HF etching on ceramic surface. Combination of HF acid and silane, remain as a gold standard treatment for glass-ceramic materials.

ste estudio evaluó la resistencia de unión entre cerámica vítrea y cemento resinoso, utilizando diferentes tratamientos de silano, sin realizar condicionamiento previo de la cerámica con ácido fluorhídrico (HF), después de almacenamiento en corto y largo plazo. Ciento ochenta placas de cerámica (IPS e.max CAD®) fueron pulidas y divididas en 6 grupos (n=30) para ser tratadas como sigue: (1) RCPRelyX Ceramic Primer® (silano de 1 frasco), (2) RCP+SB-RelyX Ceramic Primer y Adper Singlebond2® (silano más adhesivo separado), (3) SBU-Scotchbond Universal® (adhesivo universal conteniendo silano), (4) CP-Clearfil Ceramic Primer® (primer cerámico conteniendo silano y MDP), (5) NC-ningún silano (control negativo) y (6) PC-Condicionamiento con HF previo (5%, 20s) y silano (RelyX Ceramic Primer®) (control positivo). Dos cilindros de cemento resinoso (Rely X Ultimate®) fueron construidos en cada placa. Cada grupo fue dividido en 2 sub-grupos para ser almacenados por 24 horas (24h) y 6 meses (6mo) en agua destilada a 37°C (n=15). Luego fue realizada la prueba de microcizallamiento (µSBS). El tipo de fractura fue analizado con microscopio electrónico de barrido (SEM) y los datos analizados con las pruebas estadísticas ANOVA de dos factores y Tukey (α=0.05). Ambos factores y su interacción resultaron estadísticamente significativos (p≤0.05). PC presentó los valores más altos de µSBS (MPa) para ambos tiempos de almacenamiento (24h: 28.11±2.44; 6mo: 19.10±3.85). Luego de 24h, los grupos RCP+SB (10.86±3.62), SBU (8.37±4.33) y CP (8.05±3.62) no fueron estadísticamente diferentes del grupo control negativo (NC: 8.00±2.51); sólo RCP (19.73±4.63) y PC obtuvieron resultados mayores. Después de 6 meses de almacenaje, sólo el grupo PC obtuvo valores estadísticamente mayores que NC (0.04±0.01). Fractura cohesiva en el cemento fue más prevalente para RCP-24h y PC, mientras que el tipo adhesivo fue el más frecuente para todos los demás grupos. Relevancia Clínica: Ninguno de los tratamientos de silano evaluados, mejoró significativamente la adhesión a largo plazo entre cerámica vítrea no condicionada y cemento resinoso. La combinación de HF y silano, continúa siendo el tratamiento de preferencia para cerámica vítrea durante el proceso de cementación.

Comparative study on bond strength of porcelain fused to CAD/CAM and to cast pure titanium / 实用口腔医学杂志

Objective:To compare the titanium-porcelain bonding strength between CAD/CAM and cast pure titanium.Methods:Pure titanium samples were prepaired by CAD/CAMand casting respectively and fused with porcelain.The bond strength between tita-nium and porcelain of the samples was measured with three-point test.The titanium-porcelain interface was investigated under scanning electronic microscope(SEM).Results:The bond strength of CAD/CAMpure titanium to porcelain was (35.95 ±3.74)MPa and cast pure titanium to porcelain was (28.37 ±1 .98)MPa(P <0.05).SEMobservation showed that there was thin transition layer between titanium substrate and ceramic in CAD/CAM bond interface,titanium and porcelain combined closely,no obvious pores.However, there was thicker transition layer and small pore in cast pure titanium to porcelain bonding interface.Conclusion:The bonding strength of porcelain to CAD/CAMpure titanium is greater than that of porcelain to casting pure titanium.

The effect of degassing and peroxidation on the metal-ceramic bonding strength of Pd-Ag alloy / 实用口腔医学杂志

Objective:To investigate the effect of degassing and peroxidation on metal-ceramic bonding strength of Pd-Ag alloy. Methods:The metal-ceramic interface of group A (peroxidation)and B (degassing)was investigated under scanning electronic micro-scope(SEM)and energy dispersive spectrum (EDS).The bond strength between metal and ceramics was measured using a three-point bend test according to ISO9693.Results:The formation of nodules on the surface of alloy specimens was observed in both groups by SEM.The nodules on the specimens of group A were more densely than those of group B.The diameter of nodules in group B was 1 .5μm approximately.The interface of the metal-ceramic specimens had a clear transition porcelain layer and no hole or slit was present. The mean bonding strength of group A and B was (45.97 ±3.92)MPa and (49.1 1 ±6.42)MPa respectively(P=0.031 ).Conclu-sion:Degassing can improve metal-ceramic bonding strength of Pd-Ag alloy significantly.

Bonding between resin and ceramics / 대한치과보철학회지

STATEMENT OF PROBLEM: Literature showed different results on the durability of bonded ceramic restoration. PURPOSE: The purpose of this article is to review the effect of surface treatment of ceramics in resin-ceramic bond to get predictable results. MATERIAL AND METHOD: PubMed data base was utilized to search the articles which were written in English and published in 1986 and 2006. Some electronic published articles which are forthcoming to publish in paper were also included for this review. This review article focused on the effect of acid etching and silane application on the silica based ceramics. The durability of resin-ceramic bonding, the methodology for bond strength test and resin bonding to alumina or zirconia based ceramics were compared in brief at the end of the review. RESULTS AND CONCLUSION: the effect of silane application can be influenced by the contaminations of saliva or solutions. Micromechanical retention by acid etching as well as silane application plays an important role in initial and durable bond strength between resin and ceramic. The use of phosphate modified resin cement following tribochemical silica coating and silane application produced best bond strength for alumina or zirconia based ceramics.