CN113208932A

CN113208932A - Dentin adhesive composition with antibacterial function

Info

Publication number: CN113208932A
Application number: CN202011581878.0A
Authority: CN
Inventors: 张珂; 白玉兴; 吕绳漪; 岳世超; 戴子翔
Original assignee: Beijing Stomatological Hospital
Current assignee: Beijing Stomatological Hospital
Priority date: 2020-12-28
Filing date: 2020-12-28
Publication date: 2021-08-06

Abstract

A dentin adhesive composition having an antibacterial function, the adhesive component comprising, in mass fraction: 40-50% of resin monomer, 35-45% of crosslinking monomer and monofunctional group comonomer, 0.1-0.3% of photoinitiator, 0.7-0.9% of co-initiator, 2-10% of antibacterial functional monomer and 0-0.7% of filler; the method is characterized in that the filler is modified nano titanium dioxide.

Description

Dentin adhesive composition with antibacterial function

Technical Field

The invention belongs to the field of dental adhesives and preparation thereof, and particularly relates to a dentin adhesive composition with an antibacterial function.

Background

The binder is a liquid substance matched with the dental restoration composite resin, the self-acid-etching binder is acidic, the phosphoric acid etching step in the restoration process is reduced, and acid etching is completed by the polymerizable acidic functional monomer in the composition. Most of the resin-based adhesives comprise bisphenol A-glycidyl methacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), hydroxyethyl methacrylate (HEMA) and the like as main components. In general, dental adhesives always contain fillers. The development of fillers, from glass frits, silicates to nano-sized fumed silica and ion leachable glass fillers, to POSS particles (polyhedral oligomeric silsesquioxane) with unique cage structures, and the like. The filler added into the adhesive has high activity and polarity, the surface of the adhesive is generally hydrophilic, the polarity of the resin matrix is weaker, and the interface problem exists between the two, so the filler added into the adhesive needs to be pre-activated. In conventional tests, phosphate and silane compounds are used for surface treatment of minerals. The silane compounds are most commonly gamma-methylpropylacyloxypropyltrimethoxysilane (gamma-MPS or KH-570). The polymerizable quaternary ammonium salt is used for synthesizing the antibacterial dental resin material, namely, the polymerizable quaternary ammonium salt plays a role in contact antibacterial performance, a molecular structure of the polymerizable quaternary ammonium salt simultaneously has a polymerizable group capable of reacting with a resin monomer and an antibacterial functional group, and the antibacterial dental resin material can be synthesized by the method of direct addition and mixing, nanotechnology treatment, addition and mixing or surface grafting of the monomer and the like. The research of monomer MDPB and corresponding dental materials is mature in the field by Imazato et al, and the clearfilm Protect Bond which is the first international adhesive with antibacterial effect is the representative. The ideal dental antibacterial material should have high-efficiency, stable and durable antibacterial effect, and cannot destroy inherent properties of materials such as machinery, bonding and the like, and has high biological safety. The existing quaternary ammonium salt monomers still have the problems of small addition amount of antibacterial components, limited antibacterial capability and the like.

Disclosure of Invention

The dentin adhesive composition with the antibacterial function comprises the following components in percentage by mass: 40-50% of resin monomer, 35-45% of crosslinking monomer and monofunctional group comonomer, 0.1-0.3% of photoinitiator, 0.7-0.9% of co-initiator, 2-10% of antibacterial functional monomer and 0-0.7% of filler; the method is characterized in that the filler is modified nano titanium dioxide.

The modified nano titanium dioxide: and (3) carrying out surface grafting PMMA modification on the nano silicon dioxide by adopting an ATRP method.

The antibacterial functional monomer is dimethylaminoethyl methacrylate-propoxy-pyromellitic dianhydride dimethacrylate.

The resin monomer: bisphenol A Bis glycidyl methacrylate (Bis-GMA) is used as a resin matrix monomer, and triethylene glycol dimethacrylate (TEGDMA) is used as a diluent monomer to prepare matrix resin.

The initiation system is 1,7, 7-trimethyl bicyclo (2,2,1) -2,3 heptanedione, and the photoinitiator is camphorquinone CQ.

The preparation steps of the modified nano titanium dioxide are as follows:

step 1, preparing aminopropyl modified nano silicon dioxide, namely sequentially adding acetic acid into absolute ethyl alcohol, and performing ultrasonic treatment to perform complete alcoholysis; adding nano Sio into the solution₂The ultrasonic dispersion was continued, and finally the resultant solution was reacted for 24 hours under an oil bath. Centrifuging the suspension obtained after the reaction, washing and filtering the obtained solid matter, and drying the product in an oven to obtain aminopropyl modified nano silicon dioxide;

step 2, preparing acyl bromide modified nano silicon dioxide, namely adding anhydrous triethylamine into anhydrous tetrahydrofuran for ultrasonic dispersion, and stirring and cooling in an ice bath; adding aminopropyl modified nano-silica into the solution, slowly dropwise adding a mixed solution of BIBB and THF at the same time, reacting for 24 hours at 25 ℃, centrifuging a suspension obtained after the reaction, sequentially washing and centrifuging by using acetone, repeating for 2 times, washing and filtering the obtained solid substance, and drying the product in an oven to obtain aminopropyl modified nano-silica;

3, preparing the nano silicon dioxide of PMMA, namely sequentially adding SiO2-Br, methyl methacrylate vinegar and PMDETA into dimethyl sulfoxide, ultrasonically dispersing, performing oxygen discharge treatment, then adding CuBr, performing oil bath, precipitating the suspension obtained after reaction by using absolute ethyl alcohol, and repeating for 3 times; and washing the precipitate with acetone in a Soxhlet extractor, repeating for 2 times, collecting a solid product, and drying in an oven at the temperature of 600 ℃ to obtain the PMMA-modified nano silicon dioxide.

The synthesis method of the dimethylaminoethyl methacrylate-propoxy-pyromellitic dianhydride carboxylate comprises the following steps: slowly and dropwise adding dimethylaminoethyl methacrylate into propoxy pyromellitic acid dimethacrylate at a feeding molar ratio of 1:1, slightly excessive DMAEMA, magnetically stirring at room temperature, continuously monitoring reaction temperature change in the reaction process, stopping stirring when the reaction is carried out for 1.5h and the temperature of the product is completely reduced to the room temperature, and finishing the reaction.

The synthesized quaternary ammonium salt antibacterial monomer has the advantages of good solubility in a resin matrix, strong polymerization activity, realization of cross-linking polymerization during reaction, low cytotoxicity and the like; (1) after the nano silicon dioxide is subjected to surface amination and surface bromination in sequence, the PMMA is successfully grafted to the nano Si0 by using an ATRP method₂A surface of (a); the grafting amount and the molecular weight of PMMA can be controlled by controlling parameters such as reaction time, charge ratio and the like; when the reaction time of ATRP is 7min, the SiO2-PMMA is in the acetone solvent, no agglomeration is generated, and a single uniform dispersion state is presented.

Compared with SiO2-KH570, SiO2-PMMA has better dispersibility in the photocuring resin matrix, even if the addition amount reaches 15%, the dispersion can still be uniform, and after the addition amount of SiO2-KH570 reaches 5%, obvious agglomeration phenomenon occurs; under the condition of the same addition amount, the synergistic enhancement and toughening effect of the SiO2-PMMA and the micron SiO2 is better than that of SiO2-KH 570; SiO2-PMMA is evenly wrapped around the micron SiO2 filler to fill the gap between the micron Si02 filler; the SiO2-KH570 is agglomerated to form a nano filler phase, and the boundary between the nano filler phase and the micron SiO2 filler is obvious, namely the flexural modulus of the SiO2-PMMA and micron SiO2 synergistically enhanced composite resin is increased by 31.5 percent compared with the modulus of the SiO2-KH570 and micron Si02 synergistically enhanced composite resin; after the surface of the PMMA is grafted and modified, the SiOz-PMMA and the light-cured resin matrix have better interface combination, which is beneficial to improving the mechanical property of the composite resin.

Drawings

FIG. 1 is an SEM representation of a cross section of a SiO2-PMMA and PAN-PMMA reinforced composite material

FIG. 2 is a graph showing the bactericidal curves of 3 DMAEMA-PMDPM salt solutions with different concentrations against Candida albicans

Detailed Description

The preparation steps of the modified nano titanium dioxide are as follows:

step 1, preparing aminopropyl modified nano silicon dioxide, namely sequentially adding acetic acid into absolute ethyl alcohol, and performing ultrasonic treatment to perform complete alcoholysis; adding nano Sio into the solution₂The ultrasonic dispersion was continued, and finally the resultant solution was reacted for 24 hours under an oil bath. Centrifuging the suspension obtained after the reaction, washing and filtering the obtained solid substance, and drying the product in an oven to obtain the aminopropyl modified nano-particlesSilicon dioxide;

The MIC/MBC values of 3 quaternary ammonium salt monomers on 4 oral pathogenic bacteria are shown in Table 1. It can be seen that among the 3 monomers, the DMAEMA-PMDPM salt has the best antibacterial effect, the DMAEMA-MAA salt, especially the DMAEMA-PMDPM salt, has strong killing effect on streptococcus mutans and prevotella melanogenes, the differences have statistical significance (p is less than 0.05), the strains of the positive control group grow normally, and the strains of the negative control group do not grow bacteria.

In the determination of MIC and MBC of 3 quaternary ammonium salt monomers, 4 microorganisms are selected as objects for testing antibacterial effect, including gram-positive bacteria, gram-negative bacteria, fungi, aerobic bacteria, facultative anaerobes and obligate anaerobes, which are determined pathogenic bacteria of common oral diseases such as caries, periodontal disease and mucosal disease, and the selected strains have wide representativeness and can comprehensively evaluate the antibacterial performance of the monomers. From the results of the measurement, the antibacterial effect of the DMAEMA-PMDPM salt is the best, and the DMAEMA-MAA salt is the next, which is probably related to the structure of the lipophilic side chain connected to the N + and the anion structure of the quaternary ammonium compound.

TABLE 13 MIC/MBC values of quaternary ammonium salt antibacterial monomers for 4 oral pathogens

SEM characterization of the cross-section of the composite resin, after 3000 cycles of rubbing, in the control, part of the micron Si02 filler fell out of the composite resin, leaving many voids (fig. 1 a); in the composite resin reinforced and toughened by the cooperation of the Si02-PMMA and the micron Si02 filler, Si02-PMMA nano particles are uniformly distributed around the micron Si02 filler to block the shedding of the micron Sio2 filler and improve the wear resistance ((figure 1b and figure 1c)), while in the composite resin reinforced and toughened by the cooperation of the PAN-PMMA core-shell nano fiber and the micron Si02 filler, the micron Si02 filler seems to be wrapped in a three-dimensional network constructed by the nano fiber to block the shedding of the nano fiber from the composite resin, the above research results show that the Si02-PMMA nano particles and the PAN-PMMA nano fiber improve the wear resistance of the composite core-shell resin to a certain extent compared with the micron Si02 filler.

Claims

1. A dentin adhesive composition having an antibacterial function, the adhesive component comprising, in mass fraction: 40-50% of resin monomer, 35-45% of crosslinking monomer and monofunctional group comonomer, 0.1-0.3% of photoinitiator, 0.7-0.9% of co-initiator, 2-10% of antibacterial functional monomer and 0-0.7% of filler; the method is characterized in that the filler is modified nano titanium dioxide.

2. The composition as claimed in claim 1, wherein the modified nano titanium dioxide: and (3) carrying out surface grafting PMMA modification on the nano silicon dioxide by adopting an ATRP method.

3. The composition of claim 1, wherein the antibacterial functional monomer is dimethylaminoethyl methacrylate-propoxy-pyromellitic acid dimethacrylate.

4. The composition of claim 1, wherein the resin monomer: bisphenol A Bis glycidyl methacrylate (Bis-GMA) is used as a resin matrix monomer, and triethylene glycol dimethacrylate (TEGDMA) is used as a diluent monomer to prepare matrix resin.

5. The composition of claim 1, wherein the initiation system is 1,7, 7-trimethylbicyclo (2,2,1) -2,3 heptanedione and the photoinitiator is camphorquinone CQ.

6. The composition of claim 2, wherein the modified nano titanium dioxide is prepared by the following steps:

step 1, preparing aminopropyl modified nano silicon dioxide, namely sequentially adding acetic acid into absolute ethyl alcohol, and performing ultrasonic treatment for complete alcoholysis; adding nano Sio into the solution₂The ultrasonic dispersion was continued, and finally the resultant solution was reacted for 24 hours under an oil bath. Centrifuging the suspension obtained after the reaction, washing and filtering the obtained solid substance, and drying the product in an oven to obtain aminopropyl modified nano silicon dioxide;

step 2, preparing acyl bromide modified nano silicon dioxide, namely adding anhydrous triethylamine into anhydrous tetrahydrofuran for ultrasonic dispersion, and stirring and cooling in an ice bath; adding aminopropyl modified nano-silica into the solution, slowly dropwise adding a mixed solution of BIBB and THF, reacting at 25 ℃ for 24 hours after all the solutions are added, centrifuging a suspension obtained after the reaction, sequentially washing and centrifuging by using acetone, repeating for 2 times, washing and filtering the obtained solid substance, and drying the product in an oven to obtain aminopropyl modified nano-silica;

3, preparing the nano silicon dioxide of PMMA, namely sequentially adding SiO2-Br, methyl methacrylate vinegar and PMDETA into dimethyl sulfoxide, ultrasonically dispersing, performing oxygen discharge treatment, then adding CuBr, performing oil bath, precipitating the suspension obtained after reaction by using absolute ethyl alcohol, and repeating for 3 times; and (3) washing the precipitate with acetone in a Soxhlet extractor, repeating for 2 times, collecting a solid product, and drying in an oven at the temperature of 60 ℃ to obtain the PMMA-modified nano silicon dioxide.

7. The composition of claim 3, wherein the dimethylaminoethyl methacrylate-propoxyesteryl dimethacrylate is synthesized as follows: slowly and dropwise adding dimethylaminoethyl methacrylate into propoxy-pyromellitic dianhydride dimethacrylate, wherein the feeding molar ratio is 1:1, DMAEMA is slightly excessive, magnetically stirring is carried out at room temperature, the reaction temperature change is continuously monitored in the reaction process, heat is not released when the reaction is carried out for 1.5h, the temperature of the product is completely reduced to the room temperature, and the stirring is stopped at the moment, so that the reaction is finished.