Unit:
Τομέας Βασική Επιστήμη Οδοντιατρικών ΒιοϋλικώνΒιβλιοθήκη Οδοντιατρικής
Author:
Παπασπυριδάκος Παναγιώτης
Dissertation committee:
Assistant Professor Vasilios Chronopoulos, Associate Professor German O. Gallucci, Professor Asterios Doukoudakis
Original Title:
Effect of Impression Technique, Connection Type and Implant Angulation on Accuracy of Implant Impressions for Edentulous Patients
Summary:
Purpose: The purpose of this study was to compare the accuracy of conventional
and digital impression techniques for completely edentulous patients and to
determine the effect of implant connection type and angulation on the accuracy
outcomes.
Materials and Methods: An edentulous mandibular cast with 5 implants was
fabricated to serve as control cast at both implant and abutment-level. The 3
median implants were parallel, while the distal left had 10o angulation and the
distal right 15o angulation. A titanium one-piece framework was CAD/CAM milled
at abutment-level and used for clinical accuracy of fit measurements. For the
conventional polyether impressions of the master cast, a splinted and
non-splinted technique was used at implant-level and abutment-level (4 cast
groups, n=10 each). Digital impressions (n=10) were taken with an optical
intraoral scanner (TRIOS, 3shape) after connecting plastic scan bodies. Control
casts and conventional impression casts were digitized with an extraoral
high-resolution reference scanner (IScan D103i, Imetric) to obtain digital
volumes. Standard tessellation language (STL) datasets from the 5 test groups
were superimposed with STL dataset from the control cast to assess the 3-D
deviations, in regards to angulation, connection type and impression technique.
Accuracy was evaluated indirectly by assessing the fit of the implant fixed
complete dental prosthesis (IFCDP) framework on the generated casts of the test
groups, clinically and radiographically. To compare the 3-D deviations between
the control and test groups at implant-level, ANOVA and Scheffe's post-hoc test
was used, while Student’s t-test was used at abutment-level. To compare the
clinical accuracy of fit on casts of the test groups versus the control at the
implant- and abutment level, the Fisher's exact test was used. Results:
Significant 3-D deviations (p<0.001) were found between Group II (non-splinted
implant-level) and control. No significant difference was found between Groups
I (splinted implant-level), III (digital implant-level), IV (splinted
abutment-level) and V (non-splinted abutment-level) compared with the control.
Implant angulation up to 15o did not affect the 3-D accuracy of implant
impressions (p>0.001). Conclusion: The digital implant impressions were as
accurate as conventional implant impressions. The splinted implant-level
impression technique was more accurate than non-splinted for completely
edentulous patients, whereas at abutment-level there was no difference in the
accuracy. The implant angulation up to 15o did not affect the accuracy of
implant impressions. Implant connection type and impression technique did
affect the 3-D accuracy of implant impressions only with the non-splint
technique.
Keywords:
Dental implants, Digital impressions, Implant impressions, Accuracy, Framework
Number of references:
150
File:
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document.pdf
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