Core Technical Knowledge of CoCr-Valplast Removable Partial Denture

 

1. Material Science Fundamentals

Material Type	Key Components/Properties	Clinical Significance
Cobalt-Chromium Alloy (CoCr)	- 60%-65% cobalt, 25%-30% chromium, with molybdenum/nickel - Elastic modulus: 210-230 GPa; Yield strength ≥800 MPa	Provides rigid support, distributes occlusal forces to alveolar ridge, reduces stress on abutment teeth; suitable for long-term posterior loading.
Valplast Resin	- Polyamide-based elastomer (Polyamide Resin) - Shore hardness A85-90; Light transmittance ≥60%	Elastic clasps enable invisible retention; translucency mimics gingival color, avoiding metal display; superior aesthetics in anterior regions.

2. Structural Design Specifications

CoCr Framework Design:

Support Structure: Wide/thick baseplate (≥1.5mm thickness) in posterior regions; palatal/lingual bars in anterior regions for stability.

Retentive Elements: Hidden cast clasps (e.g., lingual opposing arms) or hybrid retention (combined with Valplast clasps).

Valplast Clasp Design:

Types: Gingivally approaching clasps (for short-crowned teeth); coronally approaching clasps (for long-crowned teeth).

Dimensions: Thickness: 0.8-1.2mm; width: 2-3mm; free-end length ≤5mm.

3. Mechanical-Aesthetic Balance

Retention Compensation: Valplast clasps provide 60%-70% retention force compared to metal clasps; compensated by increasing clasp quantity or adjusting path of insertion.

Aesthetic Optimization: CoCr frameworks can be veneered with porcelain/resin to hide metal (e.g., palatal side in anterior regions); Valplast clasps achieve "metal-free" appearance.

4. Industry Standards & Guidelines

International Standards:

ISO 20795-2:2013 (Partial denture base polymers)

ISO 7405 (Biological evaluation of dental materials)

Domestic Guidelines:

Prosthodontics (8th Edition)

T/CHSA 001-2019 (Technical specifications for removable partial dentures)