CN102816089A - Quaternary ammonium salt and carbamate structure containing antibacterial methyl acrylate monomer, its preparation method and application thereof - Google Patents

Abstract

The invention discloses an antibacterial methacrylate monomer containing a quaternary ammonium salt and a carbamate structure, a preparation method and an application thereof. The antibacterial methacrylate monomer containing quaternary ammonium salt and carbamate structure prepared by the invention can be used as an antibacterial component in dental restorative materials. The monomer has a quaternary ammonium salt and carbamate structure, so the dental curing resin containing the monomer has certain antibacterial properties and toughness.

Description

Antibacterial methacrylate monomer containing quaternary ammonium salt and carbamate structure and its preparation method and application

And its preparation method and application

technical field

The invention relates to a monomer that can be used as a photoinitiated polymerization system, in particular to a series of antibacterial methacrylate monomers containing a quaternary ammonium salt structure and its preparation method and application. the

Background technique

Caries is the chronic and progressive destruction of dental hard tissue caused by various factors. If a cavity is formed and not repaired in time, the lesion will develop to the deep layer, leading to complications such as pulp inflammation and periapical infection, resulting in tissue damage. Destroy and cause severe pain, and even affect the health of the whole body. Therefore, it is necessary to carry out effective restorative treatment for dental caries. the

Dental materials science is the most active research field in modern prosthodontics. It integrates materials science, life science, polymer chemistry and stomatology, and has developed rapidly in recent years. And monomers containing methacrylate structure are essential for light-curing dental restoration materials. Among them, Bis-GMA, a methacrylate monomer containing a bisphenol A structure disclosed in patents US3066112 and US6030606, has been widely used in dental restoration materials. Compared with other restoration materials, it has lower polymerization volume shrinkage High rate, high adhesion and excellent mechanical properties. Today, commercial methacrylate-based restorative materials typically contain monomers such as Bis-GMA, polyurethane methacrylate (UDMA), and triethylene glycol dimethacrylate (TEGDMA). the

Compared with traditional ceramic repair materials, methacrylate resin itself has no antibacterial activity, and plaque is easy to form on the surface. After the repair operation is completed, bacteria and microorganisms are more likely to gather on the surface of the methacrylate repair material or the leakage zone In the gap of the bonding interface, it will lead to secondary caries and even cause the restoration to fall off. Therefore, the development of methacrylate-based dental restorative materials with antibacterial activity will be one of the most effective ways to prevent secondary caries and improve bonding durability. the

One way to prepare methacrylate dental restoration materials with antibacterial activity is to introduce methacrylate monomers with antibacterial active groups (such as quaternary ammonium salt structure). A methacrylate quaternary ammonium salt monomer methacryloyloxydodecylpyridine bromide (MDPB) synthesized by Imazato and his team reported in patent US5733949 belongs to this kind of antibacterial agent. Restorative materials can not only effectively reduce the accumulation of Streptococcus mutans and microorganisms on its surface, but also chemically combine with oral polymer materials. Dental restoration materials prepared from MDPB have been successfully marketed. A monomethacrylate quaternary ammonium salt DMAE-CB developed by the team of Professor Chen Jihua of the Fourth Military Medical University also exhibits excellent antibacterial properties against oral pathogens, and the dental restoration materials prepared by it have long-lasting antibacterial properties. active. the

However, the molecular structure of MDPB and DMAE-CB only contains a methacrylate structure, and the crosslinking rate is limited when polymerized with the resin matrix monomer. If the content is too high in the material, the performance of the material will be affected. The uncrosslinked Antimicrobial monomers may also leach out of resin-based materials, which is not good for oral health, and the two monomers are difficult to mix with hydrophobic bismethacrylate monomers commonly used in dental restoration materials, such as TEGDMA. the

Contents of the invention

The purpose of the present invention is to solve the existing problems such as the lack of antibacterial properties of existing dental restorative materials and the difficult mixing and low crosslinking rate of existing antibacterial methacrylate monomers and methacrylate matrix for dental restorative materials, and provide A series of new polymethacrylate antibacterial monomers containing quaternary ammonium salt structure and carbamate structure and good compatibility with existing methacrylate monomers used in dental restoration materials, as well as their preparation method and application. the

Above-mentioned purpose of the present invention is achieved by following scheme:

    A kind of antibacterial methacrylate monomer containing quaternary ammonium salt and carbamate structure, its structural formula is as shown in formula (I):

In the structural formula (I), R ₁ is any one of the structural formula (II).

In the structural formula (II), n is any one value in 1 to 19. the

X in the structural formula (I) is any one of the structural formula (III). the

In the structural formula (I), R ₂ is any one of the structural formula (IV).

m in the structural formula (IV) is any value from 0 to 27. the

The formula (I) contains a carbamate structure. The formula (I) contains a quaternary ammonium salt structure. the

The preparation method of the antibacterial methacrylate monomer containing quaternary ammonium salt and carbamate structure, comprises the steps:

Step 1: Preparation of N, N-dialkyldiethanolamine quaternary ammonium salt

Add N-methyldiethanolamine and haloalkane into a three-necked bottle equipped with magnets, add a certain amount of solvent, reflux and stir at 40~90°C for 5-30 hours, cool to room temperature, filter, and filter the cake Vacuum drying at 25-50°C for 24-72 hours to obtain N,N-dialkyldiethanolamine quaternary ammonium salt (Q). the

Step 2: Preparation of antibacterial methacrylate monomer

Add isophorone diisocyanate (IPDI) or toluene diisocyanate (TDI) into a three-necked bottle equipped with magnets, and continuously add N,N-dialkyldiethanolamine quaternary through a constant pressure dropping funnel under stirring. Ammonium salt (Q) and catalyst, add a certain amount of solvent to reduce the viscosity of the system, react at 5~65°C for 0.5~24 hours, until the percentage of -NCO in the isocyanate system is close to the theoretical value, adjust the temperature to 15~90°C in a water bath, Then add hydroxyalkyl methacrylate compound or 2-hydroxy-1,3-dimethylacryloyloxypropane into the reactor through a constant pressure dropping funnel, add catalyst and polymerization inhibitor at the same time, and shower with solvent Wash the constant pressure dropping funnel, the reaction time is 2 to 18 hours, and then the reaction product is purified. the

Wherein the molar ratio of N-methyldiethanolamine to haloalkane is 1:1.05-1.10. the

The molar ratio of isophorone diisocyanate (IPDI) or toluene diisocyanate (TDI) to N,N-dialkyldiethanolamine quaternary ammonium salt is 2:1; - The molar ratio of 1,3-dimethylacryloyloxypropane to N, N-dialkyldiethanolamine quaternary ammonium salt is 2:1; the amount of catalyst is 0.02%~1% of the total mass of reactants; polymerization inhibition The dosage is 0.1%~0.6% of the total mass of reactants. the

The solvent is selected from ether, dichloromethane, chloroform, ethyl acetate, 1,2-dichloroethane, benzene, toluene, acetone, butanone, cyclohexanone or N,N-dimethylformamide One or more mixtures of the above. the

The catalyst is selected from one or more of triethylamine, triethylenediamine, tetramethylbutanediamine, N,N-dimethylbenzylamine, dibutyltin dilaurate, stannous octoate, etc. mixture. the

The polymerization inhibitor is selected from hydroquinone, p-benzoquinone, methyl hydroquinone, p-hydroxyanisole, 2,5-di-tert-butyl hydroquinone, 2-tert-butyl hydroquinone, etc. A mixture of one or more of the above. the

Alkyl groups in N,N-dialkyldiethanolamine quaternary ammonium salts include: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecane base, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, twenty-one Alkyl group, docosyl group, tricosyl group, tetracosyl group, pentadecyl group, hexadecyl group, heptacyl group, octadecyl group, nonacyl group , Cyclohexyl. the

Hydroxyalkyl methacrylate-based compounds include hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxypentyl methacrylate, hydroxyhexyl methacrylate, Hydroxyheptyl methacrylate, Hydroxyoctyl methacrylate, Hydroxynonyl methacrylate, Hydroxydecyl methacrylate, Hydroxyundecyl methacrylate, Hydroxydodecyl methacrylate Hydroxytridecyl methacrylate, Hydroxytetradecyl methacrylate, Hydroxypentadecyl methacrylate, Hydroxyhexadecyl methacrylate, Hydroxyheptadecyl methacrylate ester, hydroxyoctadecyl methacrylate, hydroxynonadecyl methacrylate, hydroxyeicosyl methacrylate. the

The chemical reaction equation of the above steps (taking isophorone diisocyanate, hydroxyethyl methacrylate, N-methyldiethanolamine, and n-hexadecane bromide as raw materials for example) is shown below. the

Another object of the present invention is to provide the application of the antibacterial methacrylate monomer containing quaternary ammonium salt and carbamate structure in dental restoration materials. The novel methacrylate monomer of the present invention has broad-spectrum and high-efficiency antibacterial properties after polymerization, and can be used alone or in combination with other monomers to prepare dental restoration materials in specific applications. the

Compared with prior art, the present invention has following beneficial effect:

The remarkable advantage of the novel methacrylate monomer prepared by the invention is that it has broad-spectrum and high-efficiency antibacterial properties, and can be used in dental restorative materials in combination with other monomers, and can also be used in main resins alone. Therefore, the antibacterial novel methacrylate macromonomer containing the quaternary ammonium salt structure and the carbamate structure prepared by the present invention has the potential to be developed as a dental restoration material for treating dental caries. the

Description of drawings

Figure 1 is a comparison chart of the antibacterial properties of the resin system with AB ₁ IL _n (n=10, 12, 14, 16) as the main resin and the reference resin system in the example.

Detailed ways

The present invention will be further described below in conjunction with specific examples, but the specific examples do not limit the present invention in any way. the

Example 1 AB ₁ IL ₁₀ monomer

The preparation method of AB ₁ IL ₁₀ monomer in this example includes the following steps:

Step 1: Add 5.95g of N-methyldiethanolamine and 15.55g of 1-bromododecane into a three-necked bottle equipped with magnets, add 100ml of dichloromethane, reflux and stir at 60°C for 15 hours, and cool to room temperature, filtered, and vacuum-dried the filter cake at 50°C for 72 hours to obtain N-methyl-N-dodecyldiethanolamine bromide. the

Step 2: Add 4.44g of isophorone diisocyanate and 100ml of dichloromethane into a 250ml three-neck bottle equipped with a magnet, and continuously add 3.67g of N-methyl-N-dodecyl diisocyanate while stirring After reacting ethanolamine bromide and 0.002g dibutyltin dilaurate in an oil bath at 70°C for 8 hours, add 2.60g hydroxyethyl methacrylate and 0.0107g hydroquinone and continue the reaction in an oil bath at 75°C for 20 hours , and then purify the reaction product. The product was characterized by infrared and NMR:

FT-IR: ν(cm ^-1 ) 3324(-NH), 2955(-CH ₃ ), 2927(-CH ₂ -), 2856(-CH ₂ -), 1717(-C=O), 1639(- C=CH ₂ ), 1463(-CH ₃ ), 1241(-COO-), 1166(-COC-), 815(-C=CH ₂ ), 722(-(CH2) _n -). ¹ H-NMR (CDCl ₃ , 400MHz): δ 6.85[4H, s], 6.20[2H, s], 5.60[2H, s], 4.56[4H, m], 4.29-4.32[8H, m], 3.87-3.94[4H , m], 3.75[2H, m], 3.58[2H, m], 3.45[3H, m], 2.92[4H, m], 1.95[6H, s], 1.67-1.72[6H, m], 1.18- 1.35[26H, m], 1.05[12H, j], 0.93[6H, m], 0.86-0.90[3H,t].

Example 2 AB ₁ IL ₁₂ monomer

The preparation method of AB ₁ IL ₁₂ monomer in this example comprises the following steps:

Step 1: Add 5.95g of N-methyldiethanolamine and 14.56g of 1-bromotetradecane into a three-necked bottle equipped with magnets, add 100ml of dichloromethane, reflux and stir at 80°C for 5 hours, and cool Return to room temperature, filter, and vacuum-dry the filter cake at 50°C for 72 hours to obtain N-methyl-N-tetradecyldiethanolamine bromide. the

Step 2: Add 4.44g of isophorone diisocyanate and 100ml of dichloromethane into a 250ml three-neck bottle equipped with a magnet, and continuously add 3.95g of N-methyl-N-tetradecyl diisocyanate while stirring After reacting ethanolamine bromide and 0.11g dibutyltin dilaurate in an oil bath at 70°C for 8.5 hours, add 2.60g hydroxyethyl methacrylate and 0.066g hydroquinone and continue to react in an oil bath at 75°C for 22 hours , and then purify the reaction product. The product was characterized by infrared and NMR:

FT-IR: ν(cm ^-1 ) 3331(-NH), 2954(-CH ₃ ), 2926(-CH ₂ -), 2855(-CH ₂ -), 1714(-C=O), 1639(- C=CH ₂ ), 1463(-CH ₃ ), 1245(-COO-), 1171(-COC-), 816(-C=CH ₂ ), 722(-(CH2) _n -). ¹ H-NMR (CDCl ₃ , 400MHz): δ 6.76[4H, s], 6.14[2H, s], 5.60[2H, s], 4.56[4H, m], 4.32[8H, m], 3.95[4H, m], 3.74[2H, m], 3.58[2H, m], 3.44-3.45[3H, m], 2.93[4H, m], 1.95[6H, s], 1.67-1.72[6H,m], 1.18-1.36[ 36H,m], 1.06[12H,m], 0.94[6H,m], 0.86-0.90[3H,t].

Example 3 AB ₁ IL ₁₄ monomer

The preparation method of AB ₁ IL ₁₄ monomer in this example includes the following steps:

Step 1: Add 5.95g of N-methyldiethanolamine and 15.27g of 1-bromohexadecane into a three-necked flask equipped with magnets, add 100ml of dichloromethane, reflux and stir at 70°C for 9 hours, and cool Return to room temperature, filter, and vacuum-dry the filter cake at 50°C for 72 hours to obtain N-methyl-N-hexadecyldiethanolamine bromide. the

Step 2: Add 4.44g of isophorone diisocyanate and 100ml of dichloromethane into a 250ml three-neck bottle equipped with a magnet, and continuously add 4.26g of N-methyl-N-hexadecyl diisocyanate while stirring After reacting ethanolamine bromide and 0.057g dibutyltin dilaurate in an oil bath at 75°C for 9 hours, add 2.70g hydroxyethyl methacrylate and 0.0342g hydroquinone and continue to react in an oil bath at 80°C for 24 hours , and then purify the reaction product. The product was characterized by infrared and NMR:

FT-IR: ν(cm ^-1 ) 3336(-NH), 2952(-CH ₃ ), 2926(-CH ₂ -), 2856(-CH ₂ -), 1719(-C=O), 1641(- C=CH ₂ ), 1460(-CH ₃ ), 1245(-COO-), 1169(-COC-), 818(-C=CH ₂ ), 719(-(CH2) _n -). ¹ H-NMR (CDCl ₃ , 400MHz): δ 6.72[4H, s], 6.14[2H, s], 5.60[2H, s], 4.56[4H, m], 4.32[8H, m], 3.88-3.94[4H, m ], 3.75[2H, m], 3.58[2H, m], 3.45[3H, m], 2.92-3.94[4H, m], 1.95[6H, s], 1.67-1.74[6H, m], 1.18- 1.36[40H, m], 1.06[12H, j], 0.93[6H, m], 0.86-0.90[3H, t].

Example 4 AB ₁ IL ₁₆ monomer

The preparation method of AB ₁ IL ₁₆ monomer in this example includes the following steps:

Step 1: Add 5.95g of N-methyldiethanolamine and 16.66g of 1-bromooctadecane into a three-necked flask equipped with magnets, add 100ml of dichloromethane, reflux and stir at 90°C for 4 hours, and cool Return to room temperature, filter, and vacuum-dry the filter cake at 50°C for 72 hours to obtain N-methyl-N-octadecyldiethanolamine bromide. the

Step 2: Add 4.44g of isophorone diisocyanate and 100ml of dichloromethane into a 250ml three-neck bottle equipped with a magnet, and continuously add 4.51g of N-methyl-N-octadecyl diisocyanate while stirring After reacting ethanolamine bromide and 0.0116g dibutyltin dilaurate in an oil bath at 75°C for 10 hours, add 2.70g hydroxyethyl methacrylate and 0.0699g hydroquinone and continue the reaction in an oil bath at 85°C for 24 hours , and then purify the reaction product. The product was characterized by infrared and NMR:

FT-IR: ν(cm-1) 3326-NH), 2954(-CH3), 2925(-CH2-), 2854(-CH2-), 1714(-C=O), 1638(-C=CH2) , 1461(-CH3), 1242(-COO-), 1169(-C-O-C-), 815(-C=CH2), 722(-(CH2)n-). 1H-NMR (CDCl3, 400MHz): δ 6.73 [4H, s], 6.12[2H, s], 5.59[2H, s], 4.54[4H, m], 4.31[8H, m], 3.86-3.92[4H, m], 3.73[2H, m], 3.55[2H, m], 3.41[3H,m], 2.63-3.90[4H, m], 1.94[6H, s], 1.62-1.70[6H, m], 1.17-1.34[44H, m], 1.04[ 12H, m], 0.92[6H, m], 0.85-0.88[3H, t]. 

Example 5 Mechanical properties and double bond conversion rate of dental resins containing AB ₁ IL ₁₀ , AB ₁ IL ₁₂ , AB ₁ IL ₁₄ and AB ₁ IL ₁₆ monomers

In this example, AB ₁ IL ₁₀ , AB ₁ IL ₁₂ , AB ₁ IL ₁₄ and AB ₁ IL ₁₆ monomers were mixed with TEGDMA, a diluent commonly used in dental restorative materials, respectively, and the mechanical properties of the prepared resin after curing were studied. Its resin formula is as follows:

AB ₁ FI _n :TEMDA:CQ:DMAEMA=49.3:49.3:0.7:0.7 (n=10, 12, 14, 16). The mechanical results and double bond conversion are shown in Table 1 and Table 2.

It can be seen from Table 1 that adding the synthesized AB ₁ IL ₁₀ , AB ₁ IL ₁₂ , AB ₁ IL ₁₄ and AB ₁ IL ₁₆ monomers to the resin system for dental restoration materials can endow it with good mechanical properties.

Table 1 The mechanical properties of the resin system with AB ₁ IL _n as the main resin and the reference resin system

Table 2 AB ₁ IL _n as the main resin resin system and the double bond conversion rate of the reference resin system

Example 6 Antibacterial properties of dental resins containing AB ₁ IL ₁₀ , AB ₁ IL ₁₂ , AB ₁ IL ₁₄ and AB ₁ IL ₁₆ monomers.

In this example, AB ₁ IL ₁₀ , AB ₁ IL ₁₂ , AB ₁ IL ₁₄ and AB ₁ IL ₁₆ monomers were mixed with TEGDMA, a diluent commonly used in dental restorative materials, to study the common cariogenic bacteria in the oral cavity after the prepared resin was cured. Streptococcus mutans was tested for antimicrobial activity. Its resin formula is as follows:

AB ₁ FI _n :TEMDA:CQ:DMAEMA=49.3:49.3:0.7:0.7 (n=10, 12, 14, 16). The result is shown in Figure 1.

It can be seen from Figure 1 that adding the synthesized AB ₁ IL ₁₀ , AB ₁ IL ₁₂ , AB ₁ IL ₁₄ and AB ₁ IL ₁₆ monomers to the resin system for dental restoration materials has good antibacterial properties against Streptococcus mutans, where AB ₁ IL ₁₀ had the best antibacterial properties.

Claims (10)

1. An antibacterial methacrylate monomer containing a quaternary ammonium salt and a carbamate structure, the structural formula of which is shown in formula (I):

In the structural formula (I), R _is any one of the structural formula (II):

In the structural formula (II), n is any one value in 1 to 19; In the structural formula (I), X is any one of the structural formula (III):

In the structural formula (I), R ₂ is any one of the structural formula (IV);

m in the structural formula (IV) is any value from 0 to 27. 2. The antibacterial methacrylate monomer containing quaternary ammonium salt and carbamate structure according to claim 1, characterized in that the formula (I) contains carbamate structure and quaternary ammonium salt structure . 3. the preparation method of the antibacterial methacrylate monomer containing quaternary ammonium salt and carbamate structure described in claim 1, is characterized in that this preparation method comprises the steps: Step 1: Preparation of N, N-dialkyldiethanolamine quaternary ammonium salt Add N-methyldiethanolamine and haloalkane into a three-necked bottle equipped with a magnet, add solvent to dilute, reflux and stir at 40~90°C for 5-30 hours, cool to room temperature, filter, and filter the cake at 25 Vacuum drying at -50°C for 24-72 hours to obtain N,N-dialkyldiethanolamine quaternary ammonium salt (Q); Step 2: Preparation of Antibacterial Methacrylate Monomer Add isophorone diisocyanate (IPDI) or toluene diisocyanate (TDI) into a three-necked bottle equipped with magnets, and continuously add N,N-dialkyldiethanolamine quaternary through a constant pressure dropping funnel under stirring. ammonium salt (Q) and catalyst, add solvent to reduce the viscosity of the system, react at 5~65°C until the percentage of -NCO in the isocyanate system is close to the theoretical value, adjust the temperature to 15~90°C in a water bath, and then pass through a constant pressure dropping funnel to Add hydroxyalkyl methacrylate compound or 2-hydroxyl-1,3-dimethylacryloyloxypropane into the reactor, add catalyst and polymerization inhibitor simultaneously, and rinse the constant pressure dropping funnel with solvent, The reaction time is 2 to 18 hours, and then the reaction product is purified. 4. The preparation method according to claim 3, characterized in that the reaction time at 5-65°C is 0.5-24 hours. 5. preparation method according to claim 3 is characterized in that in step one, the mol ratio of N-methyldiethanolamine and haloalkane is 1:1.05-1.10. 6. The preparation method according to claim 3, characterized in that in said step 2, the mixture of isophorone diisocyanate (IPDI) or toluene diisocyanate (TDI) and N,N-dialkyldiethanolamine quaternary ammonium salt The molar ratio is 2:1; the molar ratio of hydroxyalkyl methacrylate compound or 2-hydroxy-1,3-dimethylacryloyloxypropane to N,N-dialkyldiethanolamine quaternary ammonium salt is 2:1; the amount of catalyst is 0.02%~1% of the total mass of reactants; the polymerization inhibitor is 0.1%~0.6% of the total mass of reactants. 7. the preparation method according to claim 3 is characterized in that in step one, two, described solvent is selected from ether, methylene dichloride, chloroform, ethyl acetate, 1,2-dichloroethane, benzene , toluene, acetone, butanone, cyclohexanone or one or more mixtures of N,N-dimethylformamide; the catalyst is selected from triethylamine, triethylenediamine, tetramethylbutylene diamine, A mixture of one or more of N,N-dimethylbenzylamine, dibutyltin dilaurate, stannous octoate, etc.; the polymerization inhibitor is selected from hydroquinone, p-benzoquinone, methylhydroquinone , p-hydroxyanisole, 2,5-di-tert-butyl hydroquinone, 2-tert-butyl hydroquinone, etc.; the polymerization inhibitor is selected from hydroquinone, One or more mixtures of p-benzoquinone, methylhydroquinone, p-hydroxyanisole, 2,5-di-tert-butylhydroquinone, 2-tert-butylhydroquinone, etc. 8. preparation method according to claim 3, it is characterized in that in described step, the alkyl in N, N-dialkyldiethanolamine quaternary ammonium salt comprises: methyl, ethyl, propyl, butyl, Pentyl, Hexyl, Heptyl, Octyl, Nonyl, Decyl, Undecyl, Dodecyl, Tridecyl, Tetradecyl, Pentadecyl, Hexadecyl, Heptadecyl Octadecyl, Nonadecyl, Eicosyl, Hexadecyl, Docosyl, Tricosyl, Tetradecyl, Pentadecyl, Hexacyl Alkyl, heptacyl, octacosyl, nonacosyl or cyclohexyl. 9. The preparation method according to claim 3, characterized in that in the step, the alkyl group in the hydroxyalkyl methacrylate compound comprises: ethyl, propyl, butyl, pentyl, hexyl, heptyl Base, Octyl, Nonyl, Decyl, Undecyl, Dodecyl, Tridecyl, Tetradecyl, Pentadecyl, Hexadecyl, Heptadecyl, Octadecyl , nonadecyl or eicosyl. 10. the application of the antibacterial methacrylate monomer containing quaternary ammonium salt and carbamate structure as claimed in claim 1 as main body resin in dental restorative material. the