Effect of Different Scanning Techniques and Implant Abutment Angulations on the Accuracy of Intraoral Full-Arch Abutment Level Digital Impression for Mandibular Full-Arch Implant-Supported Fixed Prostheses
Abstract
Statement of Problem. Studies evaluating the effect of different abutment angulation and
scanning techniques on the accuracy of completely edentulous arch digital impression is lacking.
Purpose. The purpose of this in vitro study was to evaluate the effect of four different scanning
techniques and three different abutment angulations on the accuracy of intra-oral scanning of
fully edentulous mandible.
Material and methods. Three master models with four implants were 3D printed. For Model P
all implants were parallelly placed with 4 straight multi-unit abutments. For Model S and T, the
anterior implants were parallelly placed, while the posterior implants were tilted distally at 45
degrees. Model S received two anterior straight multiunit abutments and two17-degree multiunit
abutments over the posterior implants. model T received two anterior straight multiunit abut and
two 30-degree abutment over the posterior implants. Four different scanning techniques were
tested with SBs: unmodified group (UM), floss tied between SBs (F), resin dots added on the
ridge (R), scan guide connecting between the SBs (SG). Master models were scanned by a lab
scanner to obtain the master scans. Each model with each technique was scanned 10 times
(n=10). The scans were superimposed on the master scans, to measure distance and angular
deviations were measured. A two-way ANOVA test followed by post-hoc Tukey test were used
to analyze the effect of the technique and abutment angulation on accuracy of the intraoral
scanning. Intraclass Correlation Coefficient was used to measure reliability.
Results. In regard to the distance deviation, there was no statistically significant difference
between the model (P =.393), while, there was statistically significant difference between
different scan techniques (P<.001). Group R and SG techniques showed less distance deviations (P<.001), in comparison with group UM and F. In terms for the angular deviation, there was a statistically significant difference between the different scanning technique and different models (P<.001).) Model T showed significant higher angular deviation compared with Model P and S (P<.001). However, there was no significant difference between Model P and S (P=.093). In terms of scan technique, Group R and SG had significantly less angular deviation compared with Group UM and F (P<.001). The reliability of the scans was 0.862.
Conclusions. The accuracy of complete edentulous arch intra-oral scanning at the abutment level
was affected by the different scanning techniques and different abutment angulation. Adding
more anatomy or texture in between the scan bodies resulted in significantly improved accuracy.
Group R and SG had less angular and distance deviation, while group UM and F shower higher
deviation values.
Clinical implication. The evidence from this study suggests the use of additional texture or
devices for scan bodies to improve the accuracy of abutment level digital impression on
mandibular edentulous arch.
Citation
Koro, Muna Samir (2021). Effect of Different Scanning Techniques and Implant Abutment Angulations on the Accuracy of Intraoral Full-Arch Abutment Level Digital Impression for Mandibular Full-Arch Implant-Supported Fixed Prostheses. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /195763.