title: Evaluation of accuracy of multiple dental implant impressions using various splinting materials.
abstract: OBJECTIVE
  The aim of the present study was to compare the accuracy of casts obtained from nonsplinted and splinted direct impression techniques employing various splinting materials for multiple dental implants.
  
  
  METHODS
  A reference model with four Nobel Replace Select implant replicas in the anterior mandible was fabricated with denture base heat-curing acrylic resin. Impressions of the reference model were made using polyether impression material by direct nonsplinted and splinted techniques. Impressions were divided into four groups: group A: nonsplinted technique; group B: acrylic resin-splinted technique; group C: bite registration addition silicone-splinted technique; and group D: bite registration polyether-splinted technique. Four impressions were made for each group and casts were poured in type IV dental stone. Linear differences in interimplant distances in the x-, y-, and z-axes and differences in interimplant angulations in the z-axis were measured on the casts using a coordinate measuring machine.
  
  
  RESULTS
  The interimplant distance D1y showed significant variations in all four test groups (P = .043), while D3x values varied significantly between the acrylic resin-splinted and silicone-splinted groups. Casts obtained from the polyether-splinted group were the closest to the reference model in the x- and y-axes. In the z-axis, D2z values varied significantly among the three test groups (P = .009). Casts from the acrylic resin-splinted group were the closest to the reference model in the z-axis. Also, one of the three angles measured (angle 2) showed significant differences within three test groups (P = .009). Casts from the nonsplinted group exhibited the smallest angular differences.
  
  
  CONCLUSIONS
  Casts obtained from all four impression techniques exhibited differences from the reference model. Casts obtained using the bite registration polyether-splinted technique were the most accurate versus the reference model, followed by those obtained via the acrylic resin-splinted, nonsplinted, and bite registration addition silicone-splinted techniques.
authors.affiliation: Department of Prosthodontics, Ragas Dental College and Hospital, Tamil Nadu, India. rrhh81@yahoo.co.in
authors.forename: Rasasubramanian
authors.initials: R
authors.lastname: Hariharan
authors.forename: Chitra
authors.initials: C
authors.lastname: Shankar
authors.forename: Manoj
authors.initials: M
authors.lastname: Rajan
authors.forename: Mirza Rustum
authors.initials: MR
authors.lastname: Baig
authors.forename: N S
authors.initials: NS
authors.lastname: Azhagarasan
mesh_terms: D000180:Acrylic Resins; D000704:Analysis of Variance; D003758:Dental Implantation, Endosseous; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D006801:Humans; D007574:Jaw Relation Record; D003765:Models, Dental; D011145:Polyvinyls; D012833:Siloxanes; D013165:Splints
chemical_list: D000180:Acrylic Resins; D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane; C056844:Ramitec