title: The suitability of head-of-implant and conventional abutment impression techniques for implant-retained three unit bridges: an in vitro study.
abstract: This study compares the accuracy of master casts produced from impressions of implants using an abutment or a head-of-implant technique. The method used a Tandem Scanning Confocal Microscope to measure the dimensions of the gap between master casts produced by the two impression techniques and a custom made bridge. The median gap of 14 microns (interquartile range 10-17.9 microns) on the non-screwed side of the abutment impression was greater than the median gap of 7.5 microns (5-17.6 microns) for the head-of-implant impression and this difference was statistically significant (P < 0.005). In addition, the median gap on the screwed down side of the abutment impression of 10 microns, (6.3-12.1 microns) was greater than that of the head-of-implant of 5.5 microns (0.0-8.0 microns) and this difference was also statistically significant (P < 0.001). The head-of-implant impression produced a more accurate fit than the conventional abutment impression.
authors.affiliation: Division of Conservative Dentistry, GKT Dental Institute, Guy's Tower, London Bridge, London SE1 9RT, UK. david.bartlett@kcl.ac.uk
authors.forename: David W
authors.initials: DW
authors.lastname: Bartlett
authors.forename: Russell
authors.initials: R
authors.lastname: Greenwood
authors.forename: Leslie
authors.initials: L
authors.lastname: Howe
mesh_terms: D000044:Dental Abutments; D015921:Dental Implants; D003760:Dental Impression Materials / Q000737:chemistry; D003761:Dental Impression Technique; D019094:Dental Prosthesis, Implant-Supported; D003779:Denture Design; D003829:Denture, Partial; D006801:Humans; D018613:Microscopy, Confocal; D003765:Models, Dental; D015588:Observer Variation; D011336:Probability; D015203:Reproducibility of Results; D012117:Resins, Synthetic / Q000737:chemistry; D018709:Statistics, Nonparametric; D013499:Surface Properties
chemical_list: D015921:Dental Implants; D003760:Dental Impression Materials; C022821:Impregum; D012117:Resins, Synthetic