Flexible dentures, or flexible partial dentures (RPDs), are removable prosthetics made from thermoplastic materials like nylon or polyamide (e.g., Valplast, Flexite) to replace missing teeth in partially edentulous patients. They feature a flexible base and translucent clasps for esthetics and comfort, offering a less invasive, metal-free alternative to cobalt-chromium (Co-Cr) cast partial dentures (CPDs). With a tensile strength of ~100–200 MPa, they are less durable than Co-Cr (800–1,000 MPa) but more esthetic and comfortable, especially for anterior teeth or patients with metal allergies. The design process leverages CAD/CAM and DSD for precision and esthetic planning, particularly when replacing anterior teeth.
Advantages of Flexible Denture Design
- Esthetics: Translucent clasps are nearly invisible, outperforming Co-Cr’s metal clasps for anterior/premolar regions.
- Comfort: Lightweight, flexible base adapts to tissues, reducing irritation compared to rigid Co-Cr CPDs.
- Biocompatibility: Nickel-free, hypoallergenic; ideal for patients allergic to Ni-Cr (10–20% risk) or Co-Cr (<1% risk).
- Minimal Prep: No tooth alteration (unlike crowns/veneers or Co-Cr rest seats), preserving natural teeth.
- DSD Synergy: Enhances anterior esthetics, aligning with E-max/zirconia workflows for smile makeovers.
CAD Design
- Software: Import scans into CAD software (e.g., exocad, 3Shape Dental System with RPD module).
- Denture Components:
- Base: Design a flexible thermoplastic base (1–1.5 mm thick for flexibility, 2 mm in high-stress areas) to cover edentulous areas, with 1–2 mm clearance from soft tissues for hygiene.
- Clasps: Create thin (0.5–1.0 mm), translucent clasps to engage undercuts (0.25–0.5 mm) on abutment teeth. Position for esthetics (e.g., avoid visible anterior areas) and retention, guided by DSD for anterior cases.
Teeth: Place acrylic teeth (or porcelain for premium cases) on the base, using DSD to optimize anterior esthetics (e.g., golden ratio proportions, natural contours).
