Silicate Bone Graft Aerogel Resorption Control
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Solution Overview
Problem
Current bone graft substitutes, such as calcium phosphate and bioactive glasses, face challenges including long resorption times, low osseointegration rates, and pH build-up, leading to insufficient bone restoration and implant instability, which results in higher failure rates and additional costly remedial surgeries.
Innovation Solution
A silicate-based bone graft substitute with a porous structure and low density, incorporating metal cations and phosphate, is developed through a process involving gel formation, drying, and calcination, allowing for controlled resorption and enhanced osseointegration without pH build-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calcium phosphate bone graft substitutes are used, then they provide structural support for bone regeneration, but they exhibit long resorption times and low osseointegration rates
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating strontium substitution in the calcium phosphate structure (Sr-Ca-P ratio variation) and controlling crystallinity levels. These parameter changes enable tailored resorption rates while maintaining or improving osseointegration, directly resolving the contradiction between slow resorption and poor integration
Solution Approach 2:
The invention creates composite bone graft materials combining calcium phosphate with other bioactive components and controlled pore structures. This composite approach allows simultaneous optimization of resorption rate, osseointegration, and mechanical properties, addressing the limitations of pure calcium phosphate materials
2Reliability
If bioactive glasses are used as bone graft substitutes, then they achieve high osseointegration rates, but they cause pH build-up within the implant site
Solution Approach 1:
The patent modifies the chemical composition by controlling the SiO2 content and network formers in the glass structure, adjusting the ratio of network modifiers. These parameter changes buffer the pH release profile, maintaining high osseointegration while preventing excessive alkaline build-up that causes hollow implant sites
Solution Approach 2:
The invention introduces intermediate buffering components in the glass composition that mediate between the highly alkaline glass dissolution and the physiological environment. This intermediary action allows sustained ion release for bone growth while preventing harmful pH accumulation
3Quantity of substance
If melt-quench bioactive glasses are used, then they provide high density structure, but they have significantly higher density than sol-gel derived glasses which affects resorption rate
Solution Approach 1:
The patent changes the physical state parameters by producing amorphous glass structures instead of crystalline materials, and controlling pore size and distribution. These parameter changes reduce density while accelerating remodelling rate, allowing faster bone regeneration without sacrificing structural integrity
4Quantity of substance
If sol-gel bioactive glasses are used, then they have lower density and mesoporous structure, but they are prone to cracking and can only be made to limited dimensions
Solution Approach 1:
The patent employs thin film deposition techniques and controlled sintering processes that create flexible, crack-resistant structures. This approach maintains the low density and porosity benefits of sol-gel glasses while eliminating the brittleness and dimensional limitations through careful control of film thickness and microstructure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The silicate-based bone graft substitute achieves rapid apatite formation, high osseointegration rates, and tailored resorption times, reducing implant failure and improving bone regeneration, while avoiding pH-related issues.
Implementation Method 1
The build-up in pH has been shown to result in 'hollow' implant sites where the glass has been resorbed but no bone has grown in. This is thought to be due to the ion exchange process that occurs when bioactive glasses are immersed in aqueous solution.
Implementation Method 2
Bioactive glasses are silicate based amorphous solid materials typically containing a source of calcium and phosphate that once mixed with body fluids precipitate hydroxyapatite on their surface.
Implementation Method 3
The bone graft substitute has a porous structure. In some embodiments the bone graft substitute has a density of less than 1.1 gcm−3.
Data Source
AI summary
The present invention relates generally to the field of bone graft substitutes and methods for making the same, particularly the invention relates to bone graft substitutes for use in dental or orthopaedic implants. The bone graft substitutes described herein comprise a silicate based material. The silicate based material is a silicate network with a porous structure. The silicate network has one or more metal cations incorporated therein. Preferably a phosphate is also incorporated into the silicate network. The bone graft substitute may have a low density, preferably a density of less than 1.1 g/cm3. The bone graft substitute may be an aerogel or a cryogel.