PUSHING THE LIMITS OF DIGITAL: ACCURACY OF STRAUMANN EXACT™ VS. THE ANALOG GOLD STANDARD.
Objectives
The primary aim of this
clinical case is to evaluate the fully digital Straumann EXACT™ protocol against the
traditional Impregum impression.
Can a fully digital workflow
truly match the accuracy of the analog gold standard?
Step 1
Initial Presentation
- A 60-year-old male patient presented with a maxillary partial denture, a mandibular shortened dental arch, and severe tooth wear.
Step 2
Digital Wax-Up
- A digital wax-up guided the treatment plan.
- The mandibular tooth wear was restored first to establish a correct vertical dimension.
Step 3
Surgery & Implantation
- Three surgical guides and a provisional bridge were fabricated via the Straumann Smile in a Box platform.
- The maxillary teeth were extracted, and six Straumann BLX implants were placed.
- Screw-retained abutments and temporary cylinders were seated.
Step 4
Intra-Oral Pick-Up
- The provisional bridge was placed using the prosthetic guide.
- It was intra-orally picked up using composite to secure the correct position.
Step 5
Final Delivery
- The splinted bridge was carefully removed.
- It was extra-orally finished with Unifast III.
- Finally, the bridge was re-inserted into the patient's mouth for final delivery.
Goal 1
Restoring Function & Aesthetics
- Transitioning to a definitive FP1 bridge restores oral function, aesthetics, and quality of life.
- A digital wax-up guided the treatment planning to optimize the VDO, facial proportions, and restorative space.
Goal 2
Protocol Evaluation
- To evaluate the EXACT™ protocol, an Impregum impression was taken as the analog reference.
- Utilizing 'Smile in a Box' and Simeda milling kept the entire workflow seamlessly within the Straumann ecosystem.
Overview
Straumann EXACT™ Workflow
Choose Treatment Protocol
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Straumann EXACT™
Fully Digital Workflow
Analog Impregum
Conventional Workflow
Appointment 1
Straumann EXACT™ Scan Protocol
- Splinting Technique: 'BASE' scanbodies and 'LINKS' were rigidly splinted with pattern resin to overcome traditional full-arch IOS stitching limitations.
- Maxillary Scans: Digital acquisition included a pre-preparation scan of the temporary bridge, a scan of the edentulous maxilla, and a scan of the splinted scanbodies.
- Mandibular Scan: A scan of the opposing dentate mandible.
- Photography: Standardized clinical documentation.
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Appointment 2
Provisionalization
- Provisional bridge placement (torqued to 15 N/cm).
- Three periapical radiographs taken for baseline control.
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Appointment 3
Clinical evaluation & refinement
- Evaluation of the provisional after one month of functional loading.
- Modifications to occlusal plane, incisal length, buccal contours, and pontics.
- Refinements communicated to the lab to finalize the definitive design.
Appointment 4
Final delivery
- Definitive bridge fabricated on the analog model due to a 0.66° (see results) digital deviation.
- Radiographic verification, 15 N/cm torque, and screw channels sealed.
- Follow-up: One-month check-up confirmed stable occlusion and oral hygiene.
The Baseline
Three Digital Models
- Model 1 (Analog Reference): Lab scan of the stone model derived from the Impregum impression.
- Model 2 (Direct Digital): Intra-oral Straumann EXACT™ scan.
- Model 3 (Hybrid Digital): Extra-oral lab scan of the splinted EXACT™ structure using RevEX™ scanbodies.
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Model 1: Analog Reference
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Model 2: Direct Digital
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Model 3: Hybrid Digital
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Comparison 1
Model 1 vs Model 2 (EXACT™)
- The implant positions were converted to 6 virtual cylinders (4.5 x 7 mm) to assess precision.
- Part Comparison: Evaluating 3D spatial deviations between the analog cast and the direct digital scan.
- Angulation Comparison: Measuring the exact angular differences in degrees.
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Part Comparison
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0.15090.12580.10060.07550.05030.02520.0000
(mm)
Angulation Deviation
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Comparison 2
Model 1 vs Model 3 (Hybrid)
- The same volumetric and angular comparisons were executed for the extra-oral scan using RevEX™ scanbodies.
- This highlights the differences between a direct intra-oral scan and an extra-oral splinted approach.
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Part Comparison
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0.23580.19650.15720.11790.07860.03930.0000
(mm)
Angulation Deviation
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Data & Metrics
Deviation Analysis Summary
| Comparison | Mean (mm) | Median (mm) | RMS (mm) | Max Diff (mm) | SD (mm) |
|---|---|---|---|---|---|
| Analogue vs. Straumann EXACT™ | 0.0409 | 0.0375 | 0.0490 | 0.1509 | 0.0271 |
| Analogue vs. Straumann RevEX™ | 0.0679 | 0.0551 | 0.0875 | 0.2358 | 0.0552 |
| Angular Deviation | Tooth 16 | Tooth 14 | Tooth 12 | Tooth 22 | Tooth 24 | Tooth 26 |
|---|---|---|---|---|---|---|
| Analogue vs. Straumann EXACT™ | 0.66° | 0.48° | 0.11° | 0.13° | 0.26° | 0.49° |
| Analogue vs. Straumann RevEX™ | 0.44° | 0.67° | 0.83° | 0.16° | 0.37° | 0.68° |
Transformation Overview
Intra-oral Perspectives
The Definitive Suprastructure
Clinical Conclusions
- Workflow Validation: The Straumann EXACT™ protocol demonstrates superior dimensional trueness (0.0409 mm) compared to the hybrid RevEX™ approach.
- Safeguard Protocol: While EXACT™ significantly minimizes errors, peak deviations confirm that analog cast finalization remains the gold standard for full-arch rehabilitations.
Reference: Zhang, Y., et al. (2021). Accuracy of full-arch digital implant impressions: A systematic review. PubMed, 14(2), 157–179.
View Full Article (PDF)Department of Restorative Dentistry, KU Leuven • In collaboration with Labo Hoet.