title: Compressibility of two polyvinyl siloxane interocclusal record materials and its effect on mounted cast relationships.
abstract: BACKGROUND
  Addition silicones (polyvinyl siloxanes) are universally accepted as accurate and stable impression materials. They have also gained popularity as interocclusal record materials. However, it has not been defined if it is possible to work with polyvinyl siloxanes without changing the recorded maxillomandibular relations.
  
  
  OBJECTIVE
  This study examined the compressibility of 2 addition silicones as interocclusal record materials, analyzing the changes of maxillomandibular relations at the condyle region when different compressive forces are used to stabilize articulated casts.
  
  
  METHODS
  Sixteen interocclusal records, obtained from the same patient (8 of each polyvinyl siloxane, Blu-Mousse, Fast Set), were interposed between the patient casts in a new measuring system obtaining 48 curves of load versus maxillomandibular positional changes in 3 axes (x, y, z). These curves were compared with curves obtained with the casts in maximum intercuspation without interocclusal records (reference curves). Analysis of variance was used to compare maxillomandibular positional changes among the 3 groups (n = 48 each): Blu-Mousse, Fast Set, and control group or maximum intercuspation without interocclusal record.
  
  
  RESULTS
  There was no significant change in maxillomandibular relations when forces up to 1 kgf were applied to stabilize the casts related by means of Blu-Mousse and Fast Set addition silicone interocclusal records.
  
  
  CONCLUSIONS
  It is possible to use these polyvinyl siloxanes as interocclusal record materials without changing the recorded maxillomandibular relations.
authors.affiliation: Department of Restorative Dentistry, Federal University of Ceará, Brazil.
authors.forename: A A
authors.initials: AA
authors.lastname: Campos
authors.forename: D
authors.initials: D
authors.lastname: Nathanson
mesh_terms: D000704:Analysis of Variance; D019245:Compressive Strength; D003725:Dental Articulators; D003760:Dental Impression Materials / Q000737:chemistry*; D003761:Dental Impression Technique / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D007574:Jaw Relation Record; D003765:Models, Dental / Q000592:standards* / Q000706:statistics & numerical data; D011145:Polyvinyls / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry*
chemical_list: D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane