title: Measurement of the dimensions and abutment rotational freedom of gold-machined 3i UCLA-type abutments in the as-received condition, after casting with a noble metal alloy and porcelain firing.
abstract: BACKGROUND
  Laboratory processing of implant-supported prostheses may alter the surface of the abutment in contact with the implant head and thus the interface fit.
  
  
  OBJECTIVE
  This study assessed changes at the implant interface of gold-machined UCLA abutments after casting and porcelain baking in the case of single-tooth restorations.
  
  
  METHODS
  The depth (d) and width (w) of the hexagonal portion of the abutment, the apical diameter (D) of the abutment, and the abutment rotational freedom (R) were assessed for 30 gold-machined UCLA abutments before casting procedures (time 0), after casting with a noble metal alloy (time 1), and after the addition of porcelain (time 2) to detect any eventual fitting change in the abutments on the top of the implant hexagon.
  
  
  RESULTS
  No significant differences relative to all study parameters (d, w, D, and R) were observed between times 0, 1, and 2 (P=.576).
  
  
  CONCLUSIONS
  The results of this investigation suggest that, if all laboratory steps are observed carefully, changes at the implant interface of gold-machined UCLA abutments do not occur.
authors: Institute of Clinical Dentistry, University of Padova, Padova, Italy. paolo.vigolo@ntt.it
authors: P
authors: P
authors: Vigolo
authors: Z
authors: Z
authors: Majzoub
authors: G
authors: G
authors: Cordioli
mesh_terms: D000704:Analysis of Variance; D000044:Dental Abutments / Q000706:statistics & numerical data; D003735:Dental Casting Technique / Q000706:statistics & numerical data; D015921:Dental Implants / Q000706:statistics & numerical data; D003776:Dental Porcelain; D017267:Dental Prosthesis Design / Q000379:methods* / Q000706:statistics & numerical data; D006047:Gold Alloys; D012399:Rotation; D013499:Surface Properties; D013997:Time Factors
chemical_list: D015921:Dental Implants; D006047:Gold Alloys; D003776:Dental Porcelain