Pressable Dental Overlay Material Resolving Strength and Bonding Trade-offs
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Solution Overview
Problem
Current dental restoration techniques face challenges in achieving accurate margin fit, sufficient strength, and optimal shade and translucency when using zirconia frameworks, particularly with the need for intermediate liners and limitations in pressable overlay materials that can match the strength and aesthetic requirements of margin porcelains.
Innovation Solution
Development of a pressable overlay material with a flexural strength of at least 125 MPa, composed of a glass matrix phase including Li2O and MgO, which is flowable at 850° C. to 950° C., allowing direct bonding to zirconia cores without a liner and enabling full contour dental restorations with enhanced strength and aesthetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional overlay materials with low flexural strength (less than 125 MPa) are used, then the material can be pressed at lower temperatures, but the strength of the dental restoration is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the glass matrix by incorporating specific oxide combinations (alumina, magnesia, boron oxide, silica) in controlled proportions. This composition optimization enables the material to achieve flexural strength of at least 125 MPa while maintaining pressability at temperatures of 850-950°C, resolving the contradiction between strength and processing temperature
Solution Approach 2:
The patent creates a composite material system consisting of a reinforced glass matrix with multiple oxide components working together. The synergistic combination of alumina, magnesia, boron oxide, and silica creates a material that simultaneously achieves high flexural strength (≥125 MPa) and appropriate flow characteristics at pressing temperatures of 850-950°C, eliminating the need to compromise between strength and processability
2Reliability
If a liner is used as an intermediate layer between zirconia core and overlay ceramic, then bonding is improved and color is modified, but translucency is reduced and clinical space is consumed
Solution Approach 1:
The patent extracts and eliminates the intermediate liner layer from the dental restoration structure. By developing an overlay material with enhanced bonding capabilities through its specific glass matrix composition (alumina, magnesia, boron oxide, silica), the invention achieves reliable adhesion to zirconia cores directly without requiring a separate liner layer, thereby preserving translucency and maximizing clinical space
Solution Approach 2:
The overlay material is designed to perform multiple functions simultaneously: it provides structural strength (flexural strength ≥125 MPa), ensures bonding to the zirconia core through chemical composition optimization, and maintains aesthetic properties (translucency and shade). This multi-functional design eliminates the need for separate specialized layers, achieving reliable bonding without compromising translucency
3Temperature
If conventional heat pressing techniques are used with low-fusing glasses, then pressing can be performed at lower temperatures, but the maturing temperatures are not optimal for YTZP frameworks and mass production is difficult
Solution Approach 1:
The patent optimizes the chemical composition parameters of the glass matrix to achieve a balance between pressability and sintering characteristics. By incorporating specific proportions of alumina, magnesia, boron oxide, and silica, the material achieves optimal flow at pressing temperatures of 850-950°C while maintaining compatibility with YTZP framework maturing temperatures, enabling both quality bonding and efficient mass production through consistent processing parameters
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 solution provides a strong, aesthetically superior dental restoration with optimized shade, translucency, and structural integrity by eliminating the need for separate material layers and allowing for net shape formation in a single pressing operation, while maintaining the high strength of zirconia frameworks.
Implementation Method 1
a glass matrix phase... which is flowable at 850° C. to 950° C.
Data Source
AI summary
A method of making a dental article including a pressable body possessing a flexural strength of at least 125 MPa and flowable at about 850° C. to about 950° C. The body is composed of at least a glass matrix phase having a composition comprising Li2O and MgO.