Effect of splinting on the accuracy of impressions of multiple straight implants in full arch rehabilitation: An in vitro-study

Objectives: This study was conducted to assess the effect of different splinting techniques
(with and without sectioning of the splinting material) on the accuracy of impressions of multiple
straight implants in full arch rehabilitation cases.
Materials and methods: A maxillary resin printed study model with five straight fixtures was
used as the master model. Open tray impression technique was done for all groups. Three groups
were defined according to splinting of the impression copings: Group A: Impression copings were
splinted to each other using autopolymerizing acrylic resin. Group B: Impression copings were
splinted to each other using autopolymerizing acrylic resin which was sectioned with a 0.3 mm
thickness disc and reconnected with a second mix of resin. Group C: Impression copings were not
splinted to each other. For each group, five different impressions were prepared. The impressions
were poured to create the casts that were digitally scanned. The accuracy of the positions and
angulations of the implants was evaluated using a computer-graphics coordinate measurement
system.
Results: Group A showed higher angular deviation compared to group B and group C. One way
ANOVA showed statistically significant difference between the studied groups, P value was <0.001.
However, Tukey post hock test showed statistically significant difference between group A and the
other groups and no statistically significant difference between group B and group C. On the other
hand, regarding linear deviation one way ANOVA showed no statistically significant difference
between the studied groups.
Conclusion: Both split acrylic‑splinted and non-splinted implant impression techniques yield
more accurate master casts regarding angular deviation compared to splinted impression technique
without splitting.