Title Die Accuracy is Similar for Full-Arch Custom Impression Trays and Dual Arch Plastic Trays for Single Tooth Fixed Restorations
Clinical Question Is die accuracy better when using full arch custom trays in comparison to dual arch plastic trays for single tooth fixed restorations?
Clinical Bottom Line There are no significant differences in die accuracy when comparing full arch custom trays and dual arch plastic trays for fixed restorations.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
12942055Ceyhan/2003Eight patients requiring a posterior single tooth implant restoration were selected on the basis of inclusion and exclusion criteria.Comparative study
Key resultsAll patients selected for the study required restoration of a single implant and could bring their teeth together in a reproducible maximum intercuspal position. The values for the die accuracy of impressions were compared to one ITI 4 mm solid implant mounted in a custom jig and used as a test coping/standard. The only significant finding was the Bucco-lingual dimension of a dual arch metal tray compared to a plastic dual tray. Dual arch metal tray dies produced were .02 mm larger than the abutment standard compared with .003 mm for the plastic dual trays. (P=.05). Mesial-distal and occlusial-gingival dimensions were comparable for all trays tested. There were no significant differences when all dimensions were compared with the full arch custom trays and the plastic dual arch trays.
12070514Cox/20021 patient, 35 impressionsComparative study
Key resultsOne patient was used for this study and 35 silicone impressions were made and cast metal copping were cemented onto natural teeth prepared as complete crown abutment. Bucco-lingual and inter-abutment dimensions were measured. The differences between the stone dimensions and cast metal control dimensions were calculated and converted to present dimensional change. The data was analyzed with 1-way analysis of variance, Student t-test and Mann Whitney test (P<. 05) The dimensions of the copings and stone duplicates were measured with the microscope. For each dimension, difference between each die and the cast metal control was converted to percent dimensional change and means, and standard deviations were calculated. The degree of variability among impression methods was compared. The research hypothesis that triple tray impression technic doesn’t differ from full arch custom tray technic was verified. Nonetheless, there was a difference in accuracy of impressions, depended on the material was used. Thus, using triple tray with heavy body impression material was the least accurate. Therefore, the impression material played a significant role in this study. Within the limitations of this pilot study, the more rigid tray/impression material combinations more accurately replicated stone dies.
Evidence Search The following is the search strategy used in PubMed: custom tray impressions, triple tray impressions.
Comments on
The Evidence
These studies represented the full spectrum of impression trays; however the first study used a very small sample. The criteria for the findings were explicit and credible. The work-up was comprehensive and consistently applied. There was no follow-up on either study. There was no competing interest of the authors.
Applicability The trays used in these studies were representative of the two methods used in taking fixed restorative impressions. There was no significant difference in the cost of the materials. The dual arch trays seemed to promote better patient comfort.
Specialty (General Dentistry) (Prosthodontics) (Restorative Dentistry)
Keywords Full arch custom tray impressions, triple tray impressions, die accuracy.
ID# 2591
Date of submission 09/24/2013
E-mail marina.protopopova@ucdenver.edu
Author Marina Protopopova
Co-author(s) e-mail
Faculty mentor Ronald N. Brown, DDS
Faculty mentor e-mail ronald.brown@ucdenver.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
None available