Accuracy of different impression techniques for internal-connection implants.
OBJECTIVE
This study evaluated the accuracy of four implant-level impression techniques with optical microscopy on two angulated conical internal-connection implants.


METHODS
A master cast with two internal-connection implant analogs angulated 10 degrees from each other and a master framework were fabricated. Four impression techniques were examined: octagonal transfer impression coping, nonoctagonal transfer impression coping, nonoctagonal pickup impression coping, and nonoctagonal pickup impression copings joined together with autopolymerizing acrylic resin. Experimental casts were fabricated from 40 polyether impressions divided into four groups. After the master framework was seated on each of the casts, one abutment screw was tightened and marginal gap measurements between analog and abutment were recorded on the other side with an optical microscope.


RESULTS
The casts produced from nonoctagonal pickup impression techniques were more accurate than those produced using transfer impression techniques (P < .05). However, there was no statistically significant difference in the accuracy between the unsplinted and splinted methods in pickup impression techniques (P > .05) or between the use of octagonal coping and nonoctagonal coping in transfer impression techniques (P > .05).


CONCLUSIONS
The casts produced from nonoctagonal pickup impression techniques were more accurate than those produced by transfer impression techniques, regardless of whether they were splinted, for angulated conical internal-connection implants.
Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, South Korea.
Yun-Jung
YJ
Lee
Seong-Joo
SJ
Heo
Jai-Young
JY
Koak
Seong-Kyun
SK
Kim
D000180:Acrylic Resins / Q000737:chemistry; D000044:Dental Abutments; D003735:Dental Casting Technique; D015921:Dental Implants; D003760:Dental Impression Materials / Q000737:chemistry; D003761:Dental Impression Technique / Q000295:instrumentation / Q000592:standards*; D018772:Dental Marginal Adaptation / Q000592:standards*; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003830:Denture, Partial, Fixed; D006801:Humans; D011145:Polyvinyls / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties
D000180:Acrylic Resins; D015921:Dental Implants; D003760:Dental Impression Materials; D003764:Dental Materials; C022821:Impregum; D011145:Polyvinyls; D012117:Resins, Synthetic; D012833:Siloxanes; C034183:vinyl polysiloxane