A comparative analysis of the accuracy of implant master casts fabricated from two different transfer impression techniques.
OBJECTIVE
This study evaluated and compared two impression techniques in terms of their dimensional accuracies to reproduce implant positions on working casts.


METHODS
A master model was designed to simulate a clinical situation. Impressions were made using four techniques: (1) Stock open tray (SOT) technique; (2) stock closed tray (SCT) technique; (3) custom open tray (COT) technique; and (3) custom closed tray (CCT) technique. Reference points on the hexagonal silhouette of the implant on master model and onto the analogs of the obtained master casts were compared after using the four impression techniques. Measurements were made using an optical microscope, capable of recording under 50x magnifications. The means and standard deviations of all the groups and subgroups were calculated and statically analyzed using analysis of variance (ANOVA) and Tukey's test.


RESULTS
The open tray impressions showed significantly less variation from the master model and all the techniques studied were comparable.


CONCLUSIONS
All the techniques studied shown some distortion. COT showed the most accurate results of all the techniques.
Department of Prosthodontics, Bharati Vidyapeeth Dental College, Pune, Maharashtra, India.
Rupali
R
Patil
Department of Prosthodontics, Bharati Vidyapeeth Dental College, Pune, Maharashtra, India.
Pankaj
P
Kadam
Department of Prosthodontics Private Practitioners, Pune, Maharashtra, India.
Chetan
C
Oswal
Department of Prosthodontics, Bharati Vidyapeeth Dental College, Pune, Maharashtra, India.
Seema
S
Patil
Department of Pedodontics, Bharati Vidyapeeth Dental College, Pune, Maharashtra, India.
Shweta
S
Jajoo
Department of Prosthodontics, Bharati Vidyapeeth Dental College, Pune, Maharashtra, India.
Arati
A
Gachake
Closed tray impressions; custom trays; implants; open tray impression; stock tray; stock tray impressions