title: Shrinkage and strength characterization of an alumina-glass interpenetrating phase composite for dental use.
abstract: OBJECTIVE
  The aim of the study was to investigate the influence of temperature and time during partial-sintering (i.e. initial-stage sintering) on the shrinkage and strength of an alumina-glass dental composite.
  
  
  METHODS
  The alumina slip and infiltrating glass were prepared for fabrication of an interpenetrating phase composite by melt-infiltration technology. Partial-sintering temperatures for the alumina body ranged from 1050 to 1200 degrees C (2 h) and at 1125 degrees C, the time was varied from 2 to 8 h. Partially sintered alumina preform were then infiltrated with melted glass at 1125 degrees C for 6h except for one group treated at 1100 degrees C for 6 h.
  
  
  RESULTS
  The composite demonstrated shrinkage not only during initial-stage sintering of the alumina but also during infiltration of glass into the alumina preform. Higher temperatures and longer times for alumina sintering led to greater shrinkage for the alumina preform and overall for the alumina-glass infiltrated composite. However, shrinkage during the infiltration stage was lower for alumina compacts having the highest initial-stage sintering shrinkage (1200 degrees C for 2 h or at 1125 degrees C for 6 and 8 h). Strength of the composite was not influenced when sintering temperatures and times were increased.
  
  
  CONCLUSIONS
  Shrinkage during both alumina sintering and glass infiltration must be taken into account for the overall shrinkage of the alumina-glass interpenetrating phase composite. Strength does not appear to be influenced by the changes in density or preform microstructure occurring during more extensive initial-stage sintering.
authors.affiliation: Department of Prosthodontics, West China College of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China. h_wang99@yahoo.com.cn
authors.forename: Hang
authors.initials: H
authors.lastname: Wang
authors.forename: Yunmao
authors.initials: Y
authors.lastname: Liao
authors.forename: Yonglie
authors.initials: Y
authors.lastname: Chao
authors.forename: Xing
authors.initials: X
authors.lastname: Liang
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D010316:Particle Size; D016062:Porosity; D013314:Stress, Mechanical; D013499:Surface Properties; D013674:Technology, Dental; D013997:Time Factors
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D000537:Aluminum Oxide