title: Margin adaptation of indirect composite inlays fabricated on flexible dies.
abstract: BACKGROUND
  Indirect composite restorations can be made in 1 appointment using a flexible die. Interactions between different impression materials and flexible die materials may affect the accuracy of fit and margin adaptation of the restoration.
  
  
  OBJECTIVE
  This study compared the margin adaptation of composite inlays made using the following 5 impression/flexible die material combinations; condensation silicone/polyvinyl siloxane (CS/PVS), wash viscosity polyvinyl siloxane/medium or heavy viscosity polyvinyl siloxane (PVS/PVS), irreversible hydrocolloid impression/medium viscosity polyvinyl siloxane (IH/PVS), wash viscosity polyvinyl siloxane impression/polyether (PVS/PE), with composite inlays made using a control system of a wash viscosity polyvinyl siloxane impression and a type IV stone die.
  
  
  METHODS
  For each test and control system, 10 impressions were made of a class II composite inlay preparation in a metal master die. One die was made from each impression and one composite inlay was made and finished on each die (a total of 60 inlays). Inlays were placed on the master die and the margin opening at the buccal, distal, and gingival sites was recorded with a measuring microscope (x40 magnification).
  
  
  RESULTS
  The overall mean +/- SD margin openings of inlays made from the systems were as follows: PVS wash/PVS heavy viscosity 149.5 +/- 107. 4 microm; PVS wash/PVS medium viscosity 87.4 +/- 63.0 microm; IH/PVS medium viscosity 76.7 +/- 48.9 microm; CS/PVS 73.3 +/- 48.7 microm, PVS wash viscosity/PE 64.0 +/- 44.3 microm, PVS wash viscosity/stone 53.9 +/- 48.3 microm. Composite inlays made using the PVS wash viscosity/PVS heavy viscosity system had significantly larger distal, gingival, and overall mean margin openings than all other inlays (ANOVA and Fisher PLSD test; P =.05). The separating medium required between some impression and die materials did not work consistently. Composite inlays fabricated on dies made of material different than the impression material had mean buccal, distal, gingival, and overall margin openings < or =100 microm.
  
  
  CONCLUSIONS
  Composite inlays made on the CS/PVS, IH/PVS medium viscosity, PVS wash viscosity/PE flexible dies, and control PVS wash viscosity/stone dies had statistically similar (P =.05) mean buccal, distal, gingival, and overall mean margin openings that were < or =100 microm. Composite inlays made on dies that were made of the same type of material as the impression material (PVS/PVS) had mean gingival margin openings >100 microm that were significantly larger than all other systems tested (P =.05).
authors.affiliation: Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia, Canada. rbprice@is.dal.ca
authors.forename: R B
authors.initials: RB
authors.lastname: Price
authors.forename: J D
authors.initials: JD
authors.lastname: Gerrow
mesh_terms: D000464:Alginates / Q000737:chemistry; D000704:Analysis of Variance; D002133:Calcium Sulfate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003722:Dental Alloys; D003760:Dental Impression Materials / Q000737:chemistry; D018772:Dental Marginal Adaptation; D004987:Ethers / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D007284:Inlays; D008422:Materials Testing; D008853:Microscopy; D003765:Models, Dental; D018583:Pliability; D011108:Polymers / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D012828:Silicones / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D014783:Viscosity
chemical_list: D000464:Alginates; D003188:Composite Resins; D003722:Dental Alloys; D003760:Dental Impression Materials; D004987:Ethers; D006047:Gold Alloys; D011108:Polymers; D011145:Polyvinyls; D012828:Silicones; D012833:Siloxanes; C034183:vinyl polysiloxane; D002133:Calcium Sulfate