title: Setting characteristics of vinyl-polysiloxane interocclusal recording materials.
abstract: OBJECTIVE
  To investigate the elemental and molecular composition, curing efficiency, setting shrinkage strain and hardness of vinyl-polysiloxane interocclusal recording materials.
  
  
  METHODS
  The materials tested were Blu-Mousse Classic/BMC, Exabite II NDS/EXB, Futar Scan/FTS, O-Bite/OBT, Occlufast Rock/OFR, R-Si-Line Metalbite/RMB and Stone Bite/STB. Composition was examined by SEM/EDX and micro-ATR FTIR. Curing efficiency (n: 7) was evaluated by micro-ATR FTIR on unset materials and following 3, 5, and 10 min after mixing. Setting shrinkage strain (%S, n: 7) was evaluated by the bonded-disk method as a function of time up to 10 min after mixing and Shore-D hardness measurements (n: 7) were performed at setting time and after 72h storage at room temperature. Statistical analysis was performed by one-way ANOVA and paired t-tests (a: 0.05).
  
  
  RESULTS
  All materials were particle-filled vinyl-polysiloxane composites with different elemental composition. C, O and Si were found at highest concentration in all products, whereas Al, Na, Mg, Ti and Ca were additionally detected. Curing efficiency measurements ranked the products in three statistically homogeneous groups (OFR, EXB, OBT>FTS, RMB>BMC, STB) at all time intervals, except OFR which at 5 and 10 min was ranked in the second group. In all products, a statistically significant increase in %S(max) values was found in comparison with %S at setting time. Strain saturation was reached by all materials at different time intervals, except from BMC and OBT. Hardness differences were detected among materials for the same time interval and between time intervals per material.
  
  
  CONCLUSIONS
  Differences among materials were detected regarding the properties tested, which may imply variations in their clinical performance.
authors.affiliation: Department of Prosthodontics, School of Dentistry, University of Athens, 2 Thivon St., Athens, Greece. phatzi@dent.uoa.gr
authors.forename: Panayiota
authors.initials: P
authors.lastname: Hatzi
authors.forename: Michail
authors.initials: M
authors.lastname: Tzakis
authors.forename: George
authors.initials: G
authors.lastname: Eliades
mesh_terms: D000704:Analysis of Variance; D056246:Chemistry, Analytic; D002627:Chemistry, Physical; D003760:Dental Impression Materials / Q000737:chemistry*; D006244:Hardness; D008422:Materials Testing; D008854:Microscopy, Electron; D011145:Polyvinyls / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission / Q000295:instrumentation / Q000379:methods*
chemical_list: D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane