title: Comparison of the effect of implant abutment surface modifications on retention of implant-supported restoration with a polymer based cement.
abstract: BACKGROUND
  In cement-retained implant-supported restoration it is important to gain adequate retention of definitive restoration as well as retrievability of prosthesis. The surface of the abutment, alloy of the restoration and the type of cement used influences the retention of the restoration. There is a need to analyze the influence of surface modifications of abutments on the retentive capabilities of provisional implant cements.
  
  
  OBJECTIVE
  To compare the effect of implant abutment surface modifications on retention of implant-supported restoration cemented with polymer based cement.
  
  
  METHODS
  Thirty solid titanium implant abutments (ADIN), 8mm height, were divided into 3 groups. Ten abutments with retentive grooves (Group I) as supplied by the manufacturer, Ten abutments milled to 20 taper circumferentially (Group II), and Ten abutments milled and air-abraded with 110 μm aluminum oxide (Group III) were used in this study. Ni-Cr coping were casted for each abutment and polymer based cement was used to secure them to the respective abutments. Using a universal testing machine at a crosshead speed of 0.5 cm/minute, tensile bond strength was recorded (N).
  
  
  RESULTS
  Mean tensile bond strength of Group I, II and III were found to be 408.3, 159.9 and 743.8 Newton respectively. The values were statistically different from each other (p<0.001).
  
  
  CONCLUSIONS
  Abutments with milled and sandblasted surface provide the highest retention followed by abutments with retentive grooves and then by abutments with milled surface when cast copings were cemented to implant abutments with polymer based cement.
  
  
  CONCLUSIONS
  Retention of restoration depends on the surface of the abutment as well as the luting agents used. Incorporation of retentive grooves or particle abrasion can enhance retention especially in situation of short clinical crown.
authors.affiliation: Assistant Professor, Department of Prosthodontics, HiTech Dental College & Hospital , Bhubaneswar, India .
authors.forename: Nabaprakash
authors.initials: N
authors.lastname: Sahu
authors.affiliation: Assistant Professor, Department of Prosthodontics, HiTech Dental College & Hospital , Bhubaneswar, India .
authors.forename: Namratha
authors.initials: N
authors.lastname: Lakshmi
authors.affiliation: Professor & Head, Department of Prosthodontics, Ragas dental College & Hospital , Chennai, India .
authors.forename: N S
authors.initials: NS
authors.lastname: Azhagarasan
authors.affiliation: Assistant Professor, Department of Conservative dentistry & Endodontics, HiTech Dental College & Hospital , Bhubaneswar, India .
authors.forename: Yoshaskam
authors.initials: Y
authors.lastname: Agnihotri
authors.affiliation: Professor, Department of Prosthodontics, Ragas dental college & Hospital , Chennai, India .
authors.forename: Manoj
authors.initials: M
authors.lastname: Rajan
authors.affiliation: Assistant Professor, Department of Prosthodontics, Ragas Dental College & Hospital , Chennai, India .
authors.forename: Ramasubramanian
authors.initials: R
authors.lastname: Hariharan
keywords: Abutment surface modification; Implant abutment surface; Implant supported restoration