Self-adhesive Dental Composite with Hydrolysis-Stable Monomers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dental composites face challenges with high viscosity due to large filler content, leading to low adhesion to dentine and requiring additional bonding agents, which complicates application and reduces shelf life due to hydrolysis of acidic groups.
Innovation Solution
A self-adhesive dental restorative composition comprising hydrolysis-stable polymerizable monomers and a high filler content, applied as a one-pack system without a bonding agent, ensuring excellent storage stability and long-term mechanical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large amount of filler is incorporated into dental composite to provide mechanical strength and reduce polymerization shrinkage, then mechanical resistance is improved, but viscosity increases making homogeneous mixing difficult and adhesion to dentine decreases
Solution Approach 1:
The patent changes the chemical parameters of the monomer system by introducing hydrolysis-stable polymerizable monomers with specific functional groups (carboxylic acid, phosphoric acid, sulfonic acid) that provide both adhesion to dentine and compatibility with high filler loads. This allows the composite to maintain low viscosity despite high filler content (60-90 wt%), enabling homogeneous mixing while achieving both mechanical strength and adhesion.
2Ease of operation
If acidic adhesive monomers are incorporated into composite to improve adhesive properties, then adhesion to dentine is improved, but shelf life deteriorates due to hydrolysis of polymerizable monomers by acidic groups
Solution Approach 1:
The patent converts the harmful effect of acidic groups (which cause hydrolysis) into a beneficial feature by using hydrolysis-stable polymerizable monomers containing acidic functional groups. These monomers maintain their stability during storage despite the presence of acidic groups, and after curing, the acidic groups remain in the bulk providing continuous adhesion to dentine without causing hydrolysis. This resolves the contradiction by making the acidic groups beneficial for adhesion while eliminating their harmful hydrolytic effect through the selection of stable monomer structures.
3Device complexity
If dental composite is applied directly without bonding agent to simplify application, then device complexity is reduced, but adhesion strength to dentine decreases
Solution Approach 1:
The patent merges the functions of the bonding agent and the composite material into a single self-adhesive composite system. The composite contains hydrolysis-stable polymerizable monomers with acidic functional groups that provide both the adhesion function (normally provided by separate bonding agents) and the structural composite function. This eliminates the need for separate bonding agent application steps while maintaining strong adhesion to dentine, as the acidic groups in the composite directly bond to the dentine surface.
4Loss of substance
If high filler content is used to reduce polymerization shrinkage, then shrinkage is reduced, but viscosity increases preventing one-pack composition formulation
Solution Approach 1:
The patent changes the chemical composition parameters by using hydrolysis-stable polymerizable monomers with specific functional groups that provide excellent wetting and bonding characteristics. This allows the formulation of a one-pack composition with high filler content (60-90 wt%) that maintains homogeneous mixing capability despite the high filler load, eliminating the need for two-pack systems while reducing polymerization shrinkage.
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 composition achieves high adhesion to dentine and mechanical resistance, simplifying application and extending shelf life by maintaining stability and performance over the restoration's lifetime.
Implementation Method 1
a mixture of hydrolysis-stable polymerizable monomers... after curing
Data Source
AI summary
Self-adhesive dental restorative composition comprising (i) 10 to 40 percent by weight based on the total weight of the composition of a mixture of hydrolysis-stable polymerizable monomers of the following formula (I): wherein R is a m+n valent organic group having 1 to 20 carbon atoms and optionally 1 to 5 atoms selected from the group of nitrogen, oxygen and sulfur atoms; A independently represents a moiety of the following formula (II): wherein L is a hydrogen atom, a C1-6 alkyl group, a C3-8 cycloalkyl group, a C6-14 aryl group or a group of the following formula (III) wherein R′ is a hydrogen atom, a C1-6 alkyl group, a C3-8 cycloalkyl group, or a C6-14 aryl group; X is O, S, NH or NR″ wherein R″ is a C1-6 alkyl group, a C3-8 cycloalkyl group, a C6-14 aryl group; a is 0 or 1; M is a group of the following formula (IV) wherein Y is O, S, NH or NR′″ wherein R′″ is a C1-6 alkyl group, a C3-8 cycloalkyl group, a C6-14 aryl group; b is an integer of from O to 3; c is O or 1; d is an integer of from O to 3; provided that when b is O, then Y cannot be O; x is 0 or 1; y is 0 or 1; provided that x and y cannot be both 1, and provided that x cannot be 1 when L or a group of formula (III) is a hydrogen atom, and provided that when x is 0 then a is also 0, and provided that when y is 0 then b is greater than 0 or c is 0; B independently represents an acidic group; m is an integer of from 1 to 5; n is an integer of 0 to 3; and m+n is at least 2; (ii) 60 to 90 percent by weight based on the total weight of the composition of a filler; and (iii) an initiator system; wherein the portion of monomers of formula (I) wherein n is greater than 0 is at least 1 percent by weight based on the total weight of the mixture.