Cast accuracy obtained from different impression techniques at different implant angulations (in vitro study)

Area of Science:

• Dental Materials Science
• Prosthodontics
• Implant Dentistry

Background:

• Angulated dental implants can lead to inaccurate impressions.
• The choice of impression technique significantly influences the accuracy of the final cast.

Purpose of the Study:

• To compare the dimensional accuracy of definitive casts using three distinct impression techniques.
• To evaluate the impact of varying implant angulations on cast accuracy.

Main Methods:

• Three implant angulations (parallel, 15°, 30°) were tested using reference models.
• Impressions were made using indirect, unsplinted direct, and acrylic resin-splinted direct techniques (n=10 per group).
• Cast deviations were measured using a coordinate measuring machine and analyzed with ANOVA.

Main Results:

• The acrylic resin-splinted direct technique demonstrated the highest accuracy, especially at 30° angulation.
• At 15° angulation, both direct techniques (splinted and unsplinted) were more accurate than the indirect method.
• No significant difference in accuracy was observed among techniques for parallel implants.

Conclusions:

• Impression technique critically affects definitive cast accuracy.
• The acrylic resin splinted direct technique is superior for achieving accurate casts with angulated implants.
• Increased implant angulation leads to greater deformation and distortion, reducing accuracy.