As dental digitization accelerates, precise impression acquisition has become critical to the success of restorations. This article thoroughly examines the advantages, limitations, and appropriate applications of traditional silicone rubber impressions versus emerging intraoral scanning technologies, providing clinicians with professional guidance for selecting the optimal impression solution.
In fixed restorations, implant restorations, and complex aesthetic restorations, an accurate model constitutes half the battle toward success. For years, addition-curing silicone impression materials have been regarded as the “gold standard” due to their exceptional precision, stability, and user-friendliness. However, the rise of intraoral scanning technology is transforming clinical workflows with unprecedented efficiency.
I. The Traditional Champion: Core Advantages of Addition-Curing Silicone Impression Materials
The enduring popularity of addition-curing silicone rubber (typically including light-body, heavy-body, and impression paste) stems from its irreplaceable characteristics:
Exceptional dimensional stability: Its curing process involves an addition polymerization reaction that produces no byproducts, resulting in minimal shrinkage over time. This ensures high model accuracy, making it particularly suitable for cases demanding extreme precision, such as long bridges and implant guides.
Superior Detail Reproduction: Capable of precisely replicating microscopic structures like marginal contours and grooves of prepared teeth, ensuring tight restoration margins.
Excellent Hydrophilicity: High-quality hydrophilic silicone effectively displaces saliva and gingival crevicular fluid, delivering clear impressions even in the moist oral environment.
Ample Working Time: Clinicians have sufficient time for tooth preparation, gingival retraction, injection, and tray placement.
Clinical Recommendation: For multi-unit long bridges, full-mouth reconstructions, and cases with poor periodontal conditions featuring numerous subgingival margins, high-precision silicone impressions remain the more reliable choice.
II. Digital Pioneer: Revolutionary Breakthroughs in Intraoral Scanning Technology
Intraoral scanners directly digitize the patient's three-dimensional oral information, offering clear advantages:
Ultimate Efficiency and Patient Experience: Eliminates the cumbersome steps of mixing, injecting, waiting for setting, and model casting associated with traditional impressions, significantly reducing appointment time. Additionally, it avoids the gag reflex some patients experience with impression materials, enhancing comfort.
“What You See Is What You Get”: Dentists can view scan data in real-time on-screen, promptly identifying issues like undercuts in preparation surfaces or unclear margins and making immediate corrections, reducing the need for rework.
Seamless Digital Workflow: Scan data can be directly transferred to CAD/CAM systems for designing and milling restorations, or instantly sent via the internet to dental labs, enabling fully digitalized processes.
Technical Considerations: While intraoral scanner accuracy continues to improve, capturing clear subgingival margin data remains challenging in cases involving deep gingival sulci, bleeding, or poor saliva control. Additionally, the initial investment cost for the equipment is relatively high.
III. Decision-Making and Synergy: Rational Choices Based on Clinical Needs
Silicone impression material and intraoral scanning are not in a simple “replacement” relationship, but rather one of ‘complementarity’ and “synergy.”
Selection Criteria: Clinicians should comprehensively evaluate case complexity, technical proficiency, equipment budget, and laboratory processing capabilities. For routine cases like single crowns, short bridges, and veneers, intraoral scanning delivers exceptional precision and efficiency. For highly complex cases, silicone impressions remain unmatched in reliability.
Synergistic Application: An emerging approach is the “hybrid workflow.” For instance, using intraoral scanning to capture full-arch data while employing silicone rubber for detailed impressions or occlusal records of specific critical abutment teeth, then integrating both datasets in software. This approach balances efficiency with ultimate precision.
Whether adhering to the time-tested silicone impression or embracing the efficient intraoral scan, the core objective remains obtaining data that accurately reflects the oral condition. For clinicians, understanding the characteristics of both technologies and making the most appropriate choice based on specific cases is the essential path to successful restorations.