title: A comparison of stress relaxation in temporary and permanent luting cements.
abstract: OBJECTIVE
  The stress relaxation and compressive strength of resin, resin-modified glass ionomer, glass ionomer, polycarboxylate, and zinc oxide eugenol cements were measured to determine the characteristics of these materials after setting.
  
  
  METHODS
  A total of 19 luting cements including 12 permanent cements and 7 temporary cements were used. Cylindrical cement specimens (10mm long and 6mm in diameter) were obtained by chemical setting or light curing. The specimens were stored for 24-36 h in water at 37°C and were then used for the stress relaxation and compression tests. The stress relaxation test was carried out using three constant cross-head speeds of 5, 50, and 100 mm/min. Upon reaching the preset dislocation of 0.5 mm, the cross-head movement was stopped, and the load was recorded for 60s. Fractional stress loss at 1s was calculated from the relaxation curves. The compressive strength and modulus were measured at a cross-head speed of 1mm/min. Data were analyzed with the Kruskal-Wallis test and Holm's test.
  
  
  RESULTS
  A zinc oxide eugenol cement [TempBOND NX] exhibited the largest fractional stress loss. A resin cement [ResiCem] showed the largest compressive strength, while a glass ionomer cement [HY-BOND GLASIONOMER CX] showed the largest compressive modulus among all tested cements (p<0.05).
  
  
  CONCLUSIONS
  The fractional stress loss could not be classified by the cement type. Two implant cements [Multilink Implant and IP Temp Cement] showed similar properties with permanent resin cements and temporary glass ionomer cements, respectively. Careful consideration of the choice of cement is necessary.
authors.affiliation: Department of Biomaterials Science, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, Japan. einak@ms.kagoshima-u.ac.jp
authors.forename: Takahito
authors.initials: T
authors.lastname: Kanie
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kadokawa
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Nagata
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Arikawa
mesh_terms: D019245:Compressive Strength; D003738:Dental Cements; D003799:Dental Stress Analysis
chemical_list: D003738:Dental Cements