title: Characterization of Portland cement for use as a dental restorative material.
abstract: OBJECTIVE
  The aim of this study was to evaluate the suitability of fast-setting cement formulations based on Portland cement as dental core build-up materials using two different methods of testing compressive strength and evaluation of setting times.
  
  
  METHODS
  Four fast-setting cements based on Portland cement and their four respective densified with small particle (DSP) mortars were tested for setting time, constitution of cement by EDAX, and compressive strength using International and British Standards. Ordinary Portland cement (OPC) was used as a control.
  
  
  RESULTS
  All the fast-setting cements had a similar elemental composition to OPC and the setting times were less than 7 min. The compressive strength of OPC was different between the two methods (P<0.001). All the fast-setting cements tested showed no difference in compressive strength regardless of the method of testing at 1 and 7 days (P>0.05), but the cylinders showed a lower compressive strength at 28 days (P<0.05). The OPC DSP mortar showed poorer compressive strength than OPC (P<0.01) at all times for cube testing but not for cylinder testing, where no difference was observed. The fast-setting DSP mortars had a lower compressive strength at 1 day (P<0.005) with both methods. At later times, there was no difference between the cements and DSP mortars for the cubes.
  
  
  CONCLUSIONS
  The pure fast-setting cements set in <7 min and were not susceptible to changes in the compressive strength testing procedure at 1 and 7 days but at 28 days all the fast-setting cements had a significantly higher strength with the test using cubes (P<0.05). A reduction in strength was observed at 28 days in cylinder testing. Most of the cements tested did not show encouraging strengths, however, one of the prototype cements tested could be a prospective dental restorative material.
authors.affiliation: Department of Building and Civil Engineering, Faculty of Architecture and Civil Engineering, University of Malta, Malta. joz@global.net.mt
authors.forename: Josette
authors.initials: J
authors.lastname: Camilleri
authors.forename: Franco E
authors.initials: FE
authors.lastname: Montesin
authors.forename: Richard V
authors.initials: RV
authors.lastname: Curtis
authors.forename: Thomas R Pitt
authors.initials: TR
authors.lastname: Ford
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry; D019245:Compressive Strength; D003738:Dental Cements / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D004577:Electron Probe Microanalysis; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D017640:Silicates / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
chemical_list: D017610:Calcium Compounds; D003738:Dental Cements; D017640:Silicates; C472247:accelerated Portland cement; C013481:dicalcium silicate; C506393:tricalcium silicate; D000537:Aluminum Oxide