In the exacting world of modern dentistry, the materials and manufacturing processes used have a direct impact on clinical success, laboratory efficiency and most importantly, patient experience. Liquid Silicone Rubber (LSR) injection molding has emerged as a transformative technology, uniquely capable of meeting the dual demands of micron-level precision and superior soft-tissue comfort. This synergy is making it the material of choice for a growing range of advanced dental applications.
What is LSR Molding?
Liquid Silicone Rubber molding involves the use of high-purity liquid silicone to create highly detailed, flexible, and biocompatible dental devices. The process typically involves injection molding, in which liquid silicone is injected into a mold cavity under pressure, allowing for the production of intricate and precise dental components.
The Foundation of Precision
Exceptional Detail Reproduction: The low viscosity of the LSR allows it to flow like water, perfectly capturing the most intricate details of a tooth preparation, gingival sulcus, or digital model.
Minimal Shrinkage: Unlike other materials, platinum-cure LSR undergoes minimal shrinkage during curing (often less than 0.1%). This ensures that the final part is a dimensionally stable and realistic replica of the original scan or model, which is critical for creating crowns, bridges and implants that fit perfectly on the first try.
Automated consistency: The LSR molding process is highly automated, from metering and mixing to injection. This eliminates human error and ensures that every part-from the first to the thousandth part-is produced with the same, repeatable accuracy.
Biocompatibility and Safety: As a platinum-cured elastomer, LSR is hypoallergenic, odorless and tasteless.
Tailored Softness: LSR can be formulated into a wide range of Shore A hardness values. This allows dental engineers to select a soft, cushion-like material (Shore 20A) for a gingival mask or a more durable yet comfortable one (Shore 40A) for a night guard, all while maintaining material integrity.
Smooth Hygienic Surface: The molding process creates a seamless, non-porous surface that is gentle on delicate gum tissue and resistant to plaque and stain adhesion, making appliances easier to clean and more comfortable to wear.
Synergy in Action: Key Dental Solutions
The combination of precision and comfort is powerfully demonstrated in these key applications:
High-Fidelity Impressions:
LSR-based Vinyl Polysiloxane (VPS) materials are the gold standard for dental impressions. They provide the precise detail needed for complex indirect restorations while being pleasant and non-threatening to the patient during the setup process.
Aesthetic Gingival Masks:
For complex restorative cases such as full arches implants, LSR molded gingival masks are a game-changer.
Advanced Night Guard and Splints:
By superimposing soft LSR onto a rigid thermoplastic framework, the laboratory was able to create occlusion guards that provide the perfect balance of structural stability and cushioned comfort. The LSR layer absorbs the forces of bruxism (teeth grinding), protects the teeth, and reduces stress on the jaw joint, encouraging patient compliance.
Fast-setting LSRs provide a highly accurate record of patient occlusion relationships, a critical piece of information for laboratories to ensure that restorations fit harmoniously within a patient’s bite
Conclusion
Liquid silicone rubber molding is more than just a manufacturing process;