The effect of zirconia sintering temperature on flexural strength, grain size, and contrast ratio.
Clin Oral Investig
; 17(1): 269-74, 2013 Jan.
Article
em En
| MEDLINE
| ID: mdl-22358379
ABSTRACT
OBJECTIVE:
This study investigated the effect of sintering temperatures on flexural strength, contrast ratio, and grain size of zirconia. MATERIALS ANDMETHODS:
Zirconia specimens (Ceramill ZI, Amann Girrbach) were prepared in partially sintered state. Subsequently, the specimens were randomly divided into nine groups and sintered with different final sintering temperatures 1,300°C, 1,350°C, 1,400°C, 1,450°C, 1,500°C, 1,550°C, 1,600°C, 1,650°C, or 1,700°C with 120 min holding time. Three-point flexural strength (N = 198; n = 22 per group) was measured according to ISO 6872 2008. The contrast ratio (N = 90; n = 10 per group) was measured according to ISO 2471 2008. Grain sizes and microstructure of different groups were investigated (N = 9, n = 1 per group) with scanning electron microscope. Data were analyzed using one-way ANOVA with Scheffé test and Weibull statistics (p < 0.05). Pearson correlation coefficient was calculated between either flexural strength or contrast ratio and sintering temperatures.RESULTS:
The highest flexural strength was observed in groups sintered between 1,400°C and 1,550°C. The highest Weibull moduli were obtained for zirconia sintered at 1,400°C and the lowest at 1,700°C. The contrast ratio and the grain size were higher with the higher sintering temperature. The microstructure of the specimens sintered above 1,650°C exhibited defects. Sintering temperatures showed a significant negative correlation with both the flexural strength (r = -0.313, p < 0.001) and the contrast ratio values (r = -0.96, p < 0.001).CONCLUSIONS:
The results of this study showed that the increase in sintering temperature increased the contrast ratio, but led to a negative impact on the flexural strength. CLINICAL RELEVANCE Considering the flexural strength values and Weibull moduli, the sintering temperature for the zirconia tested in this study should not exceed 1,550°C.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ítrio
/
Zircônio
/
Cerâmica
/
Materiais Dentários
Tipo de estudo:
Clinical_trials
Limite:
Humans
Idioma:
En
Revista:
Clin Oral Investig
Assunto da revista:
ODONTOLOGIA
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Suíça