CN109620740B

CN109620740B - Application of carboxymethyl chitosan in preparing dentin collagen fiber demineralization material

Info

Publication number: CN109620740B
Application number: CN201910031486.8A
Authority: CN
Inventors: 余凡; 许荣宸; 牛丽娜; 陈吉华; 郑智明; 焦凯
Original assignee: Fourth Military Medical University FMMU
Current assignee: Fourth Military Medical University FMMU
Priority date: 2019-01-14
Filing date: 2019-01-14
Publication date: 2022-03-08
Anticipated expiration: 2039-01-14
Also published as: CN109620740A

Abstract

The invention discloses an application of carboxymethyl chitosan in preparing a dentin collagen fiber demineralizing material, and simultaneously provides a dentin collagen fiber demineralizing material prepared from carboxymethyl chitosan and deionized water, wherein the mass percentage concentration of the carboxymethyl chitosan is 0.1-1%. The demineralization material can be used for dentin demineralization treatment before direct or indirect dental restoration, can selectively remove mineral substances outside dentin collagen fibers, furthest retains the physical and mechanical properties of the demineralization collagen, effectively resists bacterial infection, reduces degradation and damage of an adhesive interface, and prolongs the clinical service life of adhesive restoration. The demineralization material is particularly suitable for the 'dry bonding' repair technology with lower technology sensitivity.

Description

Application of carboxymethyl chitosan in preparing dentin collagen fiber demineralization material

Technical Field

The invention belongs to the field of dental bonding repair materials, and relates to application of carboxymethyl chitosan in preparation of dentin collagen fiber demineralization materials.

Background

Dental defects caused by caries, tooth trauma, abrasion, wedge-shaped defects, acid etching, developmental deformity and the like often cause damage to normal tooth morphology, occlusion and adjacency, and have adverse effects on chewing, development, face appearance, dental pulp, periodontal tissues and even whole body health. The resin bonding repair technology is a key technology for preserving and repairing the defect of the tooth body by using the advantages of unique retention principle, prominent beautiful repair effect, convenient operation and the like, and is widely applied to many fields of oral clinical medical treatment.

The existing dentin bonding, no matter using full acid etching adhesive or self acid etching adhesive, needs to use phosphoric acid or other organic acid monomers to demineralize dentin first, expose loose collagen fiber net, the bonding resin permeates into the collagen fiber net, and is mixed with the collagen fiber net to form a mixed layer after solidification, and micro-mechanical embedding force is generated, which is the basic principle for forming dentin bonding retention force.

However, these acid-etching demineralization techniques simultaneously remove inorganic minerals in and out of the collagen fibers of dentin, so that collagen fibers collapse due to the support of the demineralized mineral, preventing the penetration of resin monomers into the demineralized fibrous web. The "dry bonding" technique using a completely blow-dried demineralized dentin surface fails to achieve satisfactory bonding strength due to insufficient penetration of the resin monomer. Existing bonding systems therefore rely on "wet bonding", i.e. the artificial retention of water from the demineralized layer after demineralization, expanding the web by hydrogen bonding of water molecules to facilitate bonding. However, in the clinical operation process, the degree of the dentin moistening cannot be accurately controlled, the technical sensitivity is high, and the reliable bonding effect is not easy to obtain. In addition, under the influence of various factors, the residual moisture of the bonding interface caused by 'wet bonding' is difficult to completely remove, and the resin bonding agent is also difficult to permeate into the gaps in the demineralized collagen fibers, so that a layer of porous (the diameter is about 20-100 nm), moisture-rich and resin-impermeable partial demineralized dentin structure, also called nano-leakage, is left between the mixed layer and the non-demineralized dentin. The degradation of the collagen fiber and the resin component in the weak area in a water-rich microenvironment is the root cause of the short service life of the currently generally accepted adhesive prosthesis.

Disclosure of Invention

In view of the drawbacks or disadvantages of the prior art, an object of the present invention is to provide use of carboxymethyl chitosan for preparing a dentin collagen fiber demineralization material.

On the basis, the invention also provides a dentin collagen fiber demineralization material. The dentin collagen fiber demineralizing material is prepared from carboxymethyl chitosan and deionized water, wherein the mass percentage concentration of the carboxymethyl chitosan is 0.1-1%.

Preferably, the pH of the dentin collagen fiber demineralization material of the present invention is 6.5 to 8.

Preferably, the carboxymethyl chitosan of the present invention is one or a mixture of two or more selected from the group consisting of O-carboxymethyl chitosan, N, O-carboxymethyl chitosan, and N, N-carboxymethyl chitosan.

Preferably, the carboxymethyl chitosan used in the present invention has a molecular weight of 40KDa or more.

Meanwhile, the invention also provides a preparation method of the dentin collagen fiber demineralization material. The provided method comprises the steps of mixing carboxymethyl chitosan with deionized water, and dissolving at room temperature to obtain the dentin collagen fiber demineralization material, wherein the mass percentage concentration of the carboxymethyl chitosan is 0.1-1%.

The application method of the dentin collagen fiber demineralization material comprises the following steps: the dentin collagen fiber demineralizing material is coated on the surface of dentin, the dentin surface is treated for 30s or shorter time, deionized water is used for washing for 10s, and the dentin collagen fiber demineralizing material is dried by air drying without oil or water or is dried by water absorption paper.

The method of the invention is suitable for the 'dry bonding' technology of completely drying the surface of the demineralized dentin. And the method of the invention is suitable for the 'wet bonding' technology for retaining the moisture in the demineralized dentin.

The invention has the following effects:

the novel dentin demineralizer prepared based on carboxymethyl chitosan has excellent calcium ion chelating capacity and macromolecular characteristics, and can exert multiple advantages when being applied to dentin bonding repair:

firstly, carboxymethyl chitosan molecules contain rich carboxyl, amino and hydroxyl, have better chelation with metal ions, can quickly chelate and adsorb calcium ions in dentin mineral substances, and realize demineralization within clinically acceptable time (30s or shorter time);

secondly, the solvent used by the carboxymethyl chitosan demineralizer is deionized water, the pH value is 6.5-8, and under the condition, the ionization degree of carboxyl hydrogen ions is high, the COO-anion content is high, and the coordination and complexation capability with calcium ions is strong;

thirdly, based on the fact that molecules with the molecular weight of more than 40KDa cannot enter the space in the dentin collagen fibers, the carboxymethyl chitosan with the molecular weight of more than 40KDa can selectively retain minerals in the fibers and only chelate minerals outside the fibers, the demineralized layer collagen can maintain a three-dimensional net structure under the support of the minerals in the fibers, the resin adhesive can be ensured to be fully permeated after exogenous moisture is removed through drying, and a 'dry adhesion' repair technology with low technical sensitivity can be used;

fourthly, the dentin collagen which reserves mineral substances in the fibers has better mechanical strength than the fully demineralized dentin, enhances the mechanical strength of the bonding interface, can reduce the damage of chewing stress and the like to the bonding interface, and prolongs the service life of the bonding prosthesis;

fifthly, the carboxymethyl chitosan has good biocompatibility, is degradable, has no toxic effect on human bodies, has antioxidant property, antibacterial and antifungal capabilities, can effectively kill residual bacteria in dentin, effectively reduces the occurrence of secondary caries, and has no stimulation on dental pulp.

In conclusion, the invention prepares the dentin demineralization material which is different from the prior acid-etching demineralization system by using the carboxymethyl chitosan, can selectively remove mineral substances outside dentin collagen fibers, furthest retains the physical and mechanical properties of the demineralization collagen, effectively resists bacterial infection, reduces the degradation damage of an adhesive interface, and prolongs the clinical service life of adhesive repair. Compared with the traditional dentin acid etching demineralizing agent, the dentin acid etching demineralizing agent has incomparable superiority, so that a 'dry bonding' repairing technology with lower technology sensitivity can be adopted clinically.

Drawings

FIG. 1 is an IR spectrum of dentin before and after being treated with a 1% carboxymethyl chitosan solution (CMCS) by mass.

FIG. 2 is a comparison of the immediate micro tensile strength of the adhesive to dentin in wet or dry adhesion mode for different dentin demineralizers, 37% Phosphoric Acid (PA) and 1% carboxymethyl chitosan (CMCS).

Detailed Description

According to the dentine demineralization material, mineral substances in dentin collagen fibers are selectively reserved in the dentine demineralization process, the three-dimensional net structure of demineralized layer collagen is maintained under the support of the mineral substances in the fibers, and the sufficient penetration of a resin adhesive can be ensured after exogenous moisture is removed through drying, so that the technical sensitivity of dentine bonding operation is greatly reduced, the degradation and damage of a bonding interface are reduced, and the clinical service life of bonding repair is prolonged.

The following are specific examples provided by the inventors to further explain the technical solutions of the present invention.

Example 1:

the material of the embodiment is N-carboxymethyl chitosan with molecular weight of 100-1000KDa, which is dissolved in deionized water to prepare a carboxymethyl chitosan solution with mass percentage concentration of 1%, and the dentin collagen fiber demineralization material is obtained after complete dissolution at room temperature, wherein the pH value of the obtained demineralization material is 6.73.

The demineralizing agent was coated on the dentin surface using an injection device, treated for 30s, rinsed for 10s with deionized water, blown for 10s with anhydrous oil-free compressed gas (dry bonding) or lightly blotted for surface moisture with absorbent paper (wet bonding), and then bonded using a dentin adhesive.

As described in example 1, the inventive demineralizer material had the following characteristics:

(1) as shown in FIG. 1, the infrared spectra before and after the dentin was treated with a carboxymethyl chitosan solution (CMCS) having a concentration of 1% by mass. After 30s of CMCS demineralization, the intensity of the characteristic peak of phosphate radical in dentin mineral is reduced, thus confirming the demineralization. The presence of minerals could still be detected after 24h of CMCS demineralization, indicating the partially demineralised nature of CMCS.

(2) Comparison of the adhesive to the micro tensile strength of dentin in either wet or dry adhesion mode after treatment of dentin with different dentin demineralizers, 37% Phosphoric Acid (PA) and 1% carboxymethyl chitosan (CMCS), as shown in figure 2. Statistical analysis was performed using 37% phosphoric acid treated for 30s for adhesion as a control, and the adhesion strength obtained by wet adhesion or dry adhesion after 1% carboxymethyl chitosan demineralizer treatment for 30s was not statistically different from that obtained by the phosphoric acid-wet adhesion group (P > 0.05), and the adhesion strength obtained by dry adhesion after 1% carboxymethyl chitosan demineralizer treatment for 30s was not statistically different from that obtained by the phosphoric acid-wet adhesion group (P > 0.05), but was significantly higher than that obtained by the phosphoric acid-dry adhesion group (P < 0.05).

Example 2:

this example differs from example 1 in that:

the material of the embodiment is N, N-carboxymethyl chitosan with the molecular weight of 60-1000KDa, the N, N-carboxymethyl chitosan is dissolved in deionized water to prepare a carboxymethyl chitosan solution with the mass percentage concentration of 0.5%, the dentin collagen fiber demineralization material is obtained after complete dissolution, and the pH value of the demineralization material of the embodiment is 7.1.

Example 3:

this example differs from example 1 in that:

the material of the embodiment is that N-carboxymethyl chitosan and N, N-carboxymethyl chitosan with molecular weight of 100-1000KDa are respectively dissolved in deionized water to prepare carboxymethyl chitosan solution with mass percent concentration of 0.1%, the two solutions are mixed in equal volume to obtain the dentin demineralizing agent, and the pH value of the demineralizing material of the embodiment is 6.54.

While the invention has been described in further detail with reference to specific preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The application of the carboxymethyl chitosan aqueous solution in preparing the dentin collagen fiber demineralization material is characterized in that the carboxymethyl chitosan aqueous solution is prepared from carboxymethyl chitosan and deionized water, and the molecular weight of the carboxymethyl chitosan is more than or equal to 40 KDa; the mass percentage concentration of the carboxymethyl chitosan in the carboxymethyl chitosan aqueous solution is 0.1-1%; the carboxymethyl chitosan is one or a mixture of two of N-carboxymethyl chitosan and N, N-carboxymethyl chitosan.

2. The use according to claim 1, wherein the aqueous solution of carboxymethyl chitosan has a pH of 6.5 to 8.

3. The use according to claim 1, wherein the dentin collagen fiber demineralization material is prepared by a method comprising: mixing carboxymethyl chitosan with deionized water, and dissolving at room temperature to obtain a dentin collagen fiber demineralization material, wherein the mass percentage concentration of the carboxymethyl chitosan is 0.1-1%, and the molecular weight of the carboxymethyl chitosan is more than or equal to 40 KDa; the carboxymethyl chitosan is one or a mixture of two of N-carboxymethyl chitosan and N, N-carboxymethyl chitosan.

4. The application of the carboxymethyl chitosan aqueous solution in preparing the dental bonding repair system is characterized in that the carboxymethyl chitosan aqueous solution is prepared from carboxymethyl chitosan and deionized water, wherein the molecular weight of the carboxymethyl chitosan is more than or equal to 40 KDa; the mass percentage concentration of the carboxymethyl chitosan in the carboxymethyl chitosan aqueous solution is 0.1-1%; the carboxymethyl chitosan is one or a mixture of two of N-carboxymethyl chitosan and N, N-carboxymethyl chitosan.

5. The use according to claim 4, wherein the aqueous solution of carboxymethyl chitosan has a pH value of 6.5 to 8.