Patent Description:
Adhesive dentistry is a branch of dentistry that has developed considerably in recent years, in which the development and increasingly widespread use of materials with adhesive properties has revolutionized many aspects of dentistry, both in the restorative and preventive fields.

Dental adhesives serve the primary purpose of ensuring the preservation of fillers or composite cements used in restorative and preventive dental treatments. Moreover, said adhesives, to be used, must be able to withstand mechanical stresses, and in particular stresses from rubbing and/or compression.

To date, dental adhesives are largely resinous preparations composed of (photo)polymerizable monomers, which can have both a structural role, and in particular having the purpose of creating a rigid three-dimensional network structure, and a functional role, through which properties of interaction with the biological environment, for example with collagen fibrils or dentin, or specific properties are conferred to the adhesives.

Among the specific properties shown by the (photo)polymerizable monomers in said resinous preparations, the antibacterial properties are of fundamental importance since they are particularly useful in preventing bacterial colonization phenomena in the dental treatment sites.

<CIT> discloses antibacterial binder compositions for dental use, which comprise (A) an antibacterial primer comprising a polymerizable antibacterial monomer having an unsaturated ethylene group and at least one or more cationic groups selected from the group consisting of ammonium bases, pyridinium bases and phosphonium bases, and a volatile solvent, and (B) an adhesive composition comprising a polymerizable monomer having a group acid, a polymerizable monomer and a polymerization initiator; and an adhesive composition for dental use, which comprises (P) an adhesive primer comprising a polymerizable monomer having an acid group, a hydrophilic polymerizable monomer and water, and (Q) a bonding agent comprising a polymerizable monomer and an acylphosphine oxide compound and an alpha-diketone compound which both serve as a polymerization initiator.

<CIT> discloses an antibacterial dental adhesive composition comprising (A) <NUM>-<NUM> wt% of an antibacterial polymerizable monomer, (B) <NUM>-<NUM> wt% of a polymerizable monomer bearing an acid group, e.g. <NUM>-(meth)acryloyloxyethyl dihydrogen phosphate, (C) <NUM>-<NUM>% by weight of a polymerizable monomer bearing a hydroxyl group, <NUM>-<NUM>% by weight of water and a polymerization catalyst.

<CIT> discloses a light-curing composition for dental restoration based on the mixture of a multifunctional prepolymer of <NUM>,<NUM>-bis-(<NUM>-(<NUM>-hydroxy-<NUM>-methacryloyloxypropoxy)phenyl)propane ("Bis-GMA") and a multifunctional prepolymer formed by replacing hydrogen atoms in the hydroxyl group with methacrylate groups in said Bis-GMA molecules, and further comprising a diluent, an inorganic filler, a photoinitiation system and other additives.

Although examples of photopolymerizable monomers which have a quaternary ammonium functionality (QAMs) acting as antibacterial agents in resinous preparations for dental use are known in the literature and on the market, the Applicant has found that said monomers have a whole series of technical and performance limitations that affect its use and performance.

In particular, the Applicant has found that the hitherto known photopolymerizable monomers which have quaternary ammonium functionalities are generally poorly soluble in organic solvents, and therefore their use is limited to dental adhesives with hydrophilic characteristics, typically primer-type formulations.

Furthermore, the Applicant has found that the present currently known and commercially available photopolymerizable monomers bearing a quaternary ammonium functionalities very often shown a structure characterized by a single methacrylic type group which can limit their use in hydrophobic highly cross-linked dental adhesives, such as bonding-type formulations.

The Applicant has also noted that, if on the one hand the achievement of a relevant antibacterial activity is desirable, it can be accompanied by an undesirable cytotoxic effect, which can compromise the possibility of contact between the compounds having antibacterial properties and the biological substrates, such as the oral mucosa. In particular, the Applicant has noted that the ISO <NUM>-<NUM> standard indicates that a reduction in cell viability greater than <NUM>% is to be considered due to a cytotoxic effect. The Applicant has found that in order to be able to use a compound in a dental adhesive it is therefore necessary to balance these two different and divergent needs.

At last, the Applicant has noted that depending on the structure of the compound, the antibacterial properties deriving from the presence of the quaternary ammonium functionality can vary and be more or less significant and that the structure of the compound can also influence its ability to enter the chain during the (photo)polymerization and, consequently, influencing the mechanical properties of the obtained resin.

Therefore, the aim of the present invention is to develop a new compound having antibacterial properties, capable of being easily and effectively used as an antibacterial monomer in a wide range of adhesive resins for dental use, without causing cytotoxic effect at the concentrations of use and without compromising the mechanical properties of the resins themselves after photopolymerization.

The Applicant has surprisingly observed that it is possible to achieve this and other desirable purposes by suitably identifying some specific structural characteristics of a compound which has quaternary ammonium functionality.

In a first aspect, therefore, the present invention relates to a compound of formula (I):.

Thanks to its specific structural characteristics, the compound according to the present invention in fact shows high antibacterial properties and the absence of unwanted cytotoxic effects, which allow it to be easily and effectively used in a wide range of dental adhesives, without compromising their mechanical properties.

In an additional aspect, the present invention further relates to a photopolymerizable composition comprising at least one compound of formula (I) according to the present invention, and at least one photopolymerization activator.

In fact the structural and antibacterial properties of the compound according to the present invention allow the compound according to the invention and the photopolymerizable compositions containing it to be used in dental treatments, for example in methods of restorative dentistry in order to prevent bacterial colonization phenomena, such as for example caries, in the sites of said treatments.

Therefore, in a further aspect, the present invention also relates to a compound of formula (I) according to the present invention or a photopolymerizable composition according to the present invention, for use in a method of dental treatment.

Thanks to the antibacterial properties deriving from the presence of the quaternary ammonium functionality, the compound of formula (I) and the photopolymerizable composition according to the invention prevent bacterial colonization phenomena in the sites of said dental treatments, especially in restorative dental treatment methods.

In a preferred fulfilment, said dental treatment is a restorative method.

Finally, in a further aspect, the present invention also relates to a compound of formula (I) according to the present invention or a photopolymerizable composition according to the present invention for use as a medicament.

The antibacterial properties deriving from the presence of the quaternary ammonium functionality make the photopolymerizable compound of formula (I) and the photopolymerizable composition according to the invention suitable for use in the medical field.

Finally, in a still further aspect, the present invention relates to the use of at least one compound of formula (I) according to the present invention as an antibacterial monomer in polymeric compositions.

Preferably, in the compound of formula (I) according to the present invention, R<NUM> is the group -(CH2)<NUM>-.

Preferably, in the compound of formula (I) according to the present invention, R<NUM> is selected from the group consisting of ethylene, n-propylene, and <NUM>,<NUM>-phenylene.

Preferably, in the compound of formula (I) according to the present invention, R<NUM> and R<NUM> are independently selected from the group consisting of: methyl, and ethyl.

Preferably, in the compound of formula (I) according to the present invention, A and B are the same.

Examples of compounds of formula (I) according to the present invention are the following:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
and
<CHM>.

In a preferred fulfilment, the compound of formula (I) according to the present invention is selected from:
<CHM>
<CHM>
and
<CHM>.

Thanks to their specific combination of structural elements, said compounds have in fact been found to be particularly preferable in terms of high antibacterial properties and easy and effective use as antibacterial monomers in a wide range of resinous preparations used as dental adhesives, without compromising their mechanical properties after light curing.

The compound according to the present invention can be prepared according to any of the methods known to the skilled in the art in order to obtain a compound bearing a quaternary ammonium function.

The compound according to the present invention can be synthesized, for example, via the Menschutkin reaction between <NUM> equivalent of di-halide and <NUM>-<NUM> equivalents of tertiary amine in acetonitrile or ethanol (halide concentration <NUM>-<NUM>), adopting reaction temperatures in the range <NUM>-<NUM>, reaction times from <NUM>-<NUM> days. Under these conditions, a final yield generally higher than <NUM>% is obtained. At the end of the reaction, the product is then isolated by spontaneous precipitation in the reaction medium or by precipitation induced by acetonitrile/diethyl ether, acetonitrile/ethyl acetate, dichloromethane/ethyl acetate, dichloromethane/diethyl ether.

In an additional aspect thereof, the present invention further relates to a photopolymerizable composition comprising at least one compound of formula (I) according to the present invention, and at least one photopolymerization activator.

The structural and antibacterial properties of the compound according to the present invention, in fact, allow the compound according to the invention and the photopolymerizable compositions containing it to be used in dental treatments, for example in methods of restorative dentistry in order to prevent bacterial colonization phenomena, such as for example caries, in the sites of said treatments. In said compositions, the compound of formula (I) according to the present invention acts as a photopolymerizable monomer bearing quaternary ammonium functionality with an antibacterial effect, thus allowing the prevention of bacterial colonization, such as for example caries, in the sites where said composition is applied and subsequently photopolymerized.

Preferably, the photopolymerizable composition comprises from <NUM>% to <NUM>% by weight of the at least one compound of formula (I) according to the present invention.

Preferably, in the photopolymerizable composition the at least one photopolymerization activator is selected from any of the photopolymerization activators known for the purpose to the person skilled in the art, more preferably in the group consisting of: camphorquinone (CQ), diphenyl-(<NUM>,<NUM>,<NUM>-trimethylbenzoyl)phosphine oxide (TPO), and phenylpropanedione (PPD), and <NUM>-hydroxy-<NUM>-methoxy benzophenone (UV-<NUM>).

Preferably, the photopolymerizable composition comprises from <NUM> to <NUM>% by weight, more preferably from <NUM> to <NUM>% by weight, with respect to the total weight of the photopolymerizable compounds of the composition, of the at least one photopolymerization activator.

Preferably, the photopolymerizable composition according to the present invention comprises at least one photopolymerization co-activator.

Preferably, in the photopolymerizable composition the at least one photopolymerization co-activator is selected from any of the photopolymerization co-activators known for the purpose to the skilled in the art, more preferably in the group consisting of: ethyl-<NUM>-dimethylamino benzoate (EDMAB), and <NUM>-(ethylhexyl)-<NUM>-(dimethylamino) benzoate (ODMAB), and N,N-di(<NUM>-hydroxy ethyl)-<NUM>-toluidine (DHEPT).

Preferably, the photopolymerizable composition comprises from <NUM> to <NUM>% by weight, more preferably from <NUM> to <NUM>% by weight, with respect to the total weight of the photopolymerizable compounds of the composition, of the at least one photopolymerization co-activator.

Preferably, the photopolymerizable composition comprises, in addition to the at least one compound of formula (I) according to the present invention, at least one further compound comprising at least one ethylenic unsaturated group.

The at least one ethylenic unsaturated group allows said further compound to act as a monomer in the photopolymerizable composition according to the invention.

Preferably, in the photopolymerizable composition the at least one further compound comprising at least one ethylenic unsaturated group is selected from any of the compounds known for the purpose to the skilled in the art, more preferably from the group consisting of: hydroxyethyl methacrylate (HEMA), urethane-dimethacrylate (UDMA), bisphenol A glycidyl dimethacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), <NUM>-methacryloyloxydecyl dihydrogen phosphate (<NUM>-MDP), Bis[<NUM>-(methacryloyloxy)ethyl]phosphate (Bis-MP), methacrylic acid (MA), methyl methacrylate (MMA), <NUM>-hydroxyethyl methacrylate phosphate (HEMA-phosphate), <NUM>-hydroxypropyl methacrylate (HPMA), <NUM>-acrylamido-<NUM>-methyl-sulfonic acid (AMPS), ethylene glycol dimethacrylate (EGDMA), glycerol dimethacrylate (GDMA), <NUM>,<NUM>-dodecanediol dimethacrylate (DDDMA), glycerophosphoric acid dimethacrylate (GPDM), bis[<NUM>-(methacryloyloxy)ethyl] phosphate (Bis-MEP), mono(<NUM>-methacryloyloxy)ethyl phthalate (MMEP or PAMA), mono(<NUM>-methacryloyloxy-<NUM>-hydroxy)ethyl phthalate (PAMM), N-(<NUM>-hydroxy-<NUM>-((<NUM> methyl-<NUM>-oxo-<NUM>-propenyl)oxy)propyl)-N-tolyl glycine (NTG-GMA), N-phenylglycine glycidyl methacrylate (NPG-GMA), <NUM>-methacryloyloxyethyl trimellic anhydride (<NUM>-META), <NUM>-methacryloyloxyethyl trimellic acid (<NUM>-MET), <NUM>,<NUM>-hexanediol dimethacrylate (HDDMA), <NUM>-methacryloyloxy-<NUM>,<NUM>-undecanedicarboxylic acid (MAC-<NUM>), polyethylene glycol dimethacrylate (PEGDMA), biphenyl dimethacrylate (BPDM), di-<NUM>-methacryloyloxyethyl phosphate (di-HEMA phosphate), dimethylaminoethyl dimethacrylate (DMAEMA), di-<NUM>-butane-<NUM>,<NUM>,<NUM>,<NUM>-tetracarboxylic acid hydroxyethyl methacrylate (TCB), N-methacryloyl-<NUM>-amino salicylic acid (<NUM>-NMSA or MASA), pentamethacryloyloxyethyl cyclohexaphosphazene fluoride (PEM-F), di-pentaerythritol penta-acrylate monophosphate (PENTA), <NUM>-(methacryloxyethyl)phenyl hydrogen phosphate (Phenyl-P), <NUM>,<NUM>-dimethacryloyloxyethyloxycarbonyl-<NUM>,<NUM>-benzene dicarboxylic acid (PMDM), <NUM>,<NUM>-bis(<NUM>,<NUM>-dimethacryloyloxyprop-<NUM>-yloxycarbonyl)benzen-<NUM>,<NUM>-dicarboxylic acid (PMGDM), tetra-methacryloyloxyethyl pyrophosphate (Pyro-HEMA), <NUM>-acryloxyethyl trimellic anhydride (<NUM>-AETA), <NUM>-acryloxyethyl trimellic acid (<NUM>-AET), trimethylpropane trimethacrylate (TMPTMA).

In a preferred embodiment, the photopolymerizable composition according to the present invention comprises from <NUM>% to <NUM>% by weight, with respect to the total weight of photopolymerizable compounds of the composition, of at least one further compound comprising at least one ethylenic unsaturated group, wherein said at least a further compound comprising at least one ethylenic unsaturated group is of the hydrophilic type and is selected from the group consisting of: hydroxyethyl methacrylate (HEMA), methacrylic acid (MA), methyl methacrylate (MMA), <NUM>-hydroxyethyl methacrylate phosphate (HEMA-phosphate), <NUM>-hydroxy propyl methacrylate (HPMA), <NUM>-acrylamido-<NUM>-methyl-sulfonic acid (AMPS).

The presence of said amount of the at least one further compound comprising at least one ethylenic unsaturated group of the hydrophilic type makes such a composition particularly useful in supporting and hydrating the collagen fibrils, advantageously allowing the use of the composition for the so-called primer formulations.

In a further preferred embodiment, the photopolymerizable composition according to the present invention comprises from <NUM> to <NUM>% by weight, with respect to the total weight of photopolymerizable compounds of the composition, of at least one further compound comprising at least one ethylenic unsaturated group, wherein said at least a further compound comprising at least one ethylenic unsaturated group is of the hydrophobic-type and is selected from the group consisting of: urethane-dimethacrylate (UDMA), bisphenol A glycidyl dimethacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), <NUM>-methacryloyloxydecyl dihydrogen phosphate (<NUM>-MDP), Bis[<NUM>-(methacryloyloxy)ethyl]phosphate (Bis-MP), ethylene glycol dimethacrylate (EGDMA), glycerol dimethacrylate (GDMA), <NUM>,<NUM>-dodecanediol dimethacrylate (DDDMA), glycerophosphoric acid dimethacrylate (GPDM), bis[<NUM>-(methacryloyloxy)ethyl] phosphate (Bis-MEP), mono(<NUM>-methacryloyloxy)ethyl phthalate (MMEP or PAMA), mono(<NUM>-methacryloyloxy-<NUM>-hydroxy)ethyl phthalate (PAMM), N-(<NUM>-hydroxy-<NUM>-((<NUM> methyl-<NUM>-oxo-<NUM>-propenyl)oxy)propyl)-N-tolyl glycine (NTG-GMA), N-phenylglycine glycidyl methacrylate (NPG-GMA), <NUM>-methacryloyloxyethyl trimellic anhydride (<NUM>-META), <NUM>-methacryloyloxyethyl trimellic acid (<NUM>-MET), <NUM>,<NUM>-hexanediol dimethacrylate (HDDMA), <NUM>-methacryloyloxy-<NUM>,<NUM>-undecanedicarboxylic acid (MAC-<NUM>), polyethylene glycol dimethacrylate (PEGDMA), biphenyl dimethacrylate (BPDM), di-<NUM>-methacryloyloxyethyl phosphate (di-HEMA phosphate), dimethylaminoethyl dimethacrylate (DMAEMA), di-<NUM>-butane-<NUM>,<NUM>,<NUM>,<NUM>-tetracarboxylic acid hydroxyethyl methacrylate (TCB), N-methacryloyl-<NUM>-amino salicylic acid (<NUM>-NMSA or MASA), pentamethacryloyloxyethyl cyclohexaphosphazene fluoride (PEM-F), di-pentaerythritol penta-acrylate monophosphate (PENTA), <NUM>-(methacryloxyethyl)phenyl hydrogen phosphate (Phenyl-P), <NUM>,<NUM>-dimethacryloyloxyethyloxycarbonyl-<NUM>,<NUM>-benzene dicarboxylic acid (PMDM), <NUM>,<NUM>-bis(<NUM>,<NUM>-dimethacryloyloxyprop-<NUM>-yloxycarbonyl)benzen-<NUM>,<NUM>-dicarboxylic acid (PMGDM), tetra-methacryloyloxyethyl pyrophosphate (Pyro-HEMA), <NUM>-acryloxyethyl trimellic anhydride (<NUM>-AETA), <NUM>-acryloxyethyl trimellic acid (<NUM>-AET), trimethylpropane trimethacrylate (TMPTMA).

The presence of said amount of at least one further compound comprising at least one ethylenic unsaturated group of the hydrophobic-type makes such a composition particularly useful for the formation of a hybrid layer with dentin, advantageously allowing the use of the composition for the so-called bonding formulations.

Preferably, the photopolymerizable composition according to the present invention comprises at least one solvent. Said solvent is advantageously selected from all the solvents commonly used for the production of photopolymerizable compositions for dental use.

Preferably said solvent is selected from the group consisting of: ethanol, acetone, water, and isopropanol.

In addition to the aforementioned components, the photopolymerizable composition according to the present invention advantageously contains one or more additional components known to the skilled in the art, such as for example: inorganic fillers, <NUM>-methoxy phenol (MEHQ, inhibitor), <NUM>,<NUM>-di(tert-butyl)-<NUM>-methyl phenol (BHT, inhibitor), sodium fluoride (NaF).

In a further aspect, the present invention also relates to a compound of formula (I) according to the present invention or a photopolymerizable composition according to the present invention, for use in a method of dental treatment.

Thanks to the antibacterial properties deriving from the presence of the quaternary ammonium functionality, the compound of formula (I) and the photopolymerizable composition according to the invention prevent bacterial colonization phenomena in the sites of said dental treatments, especially in restorative dental methods.

In a preferred embodiment, said dental treatment is a restorative method.

Finally, as an additional aspect, the present invention also relates to a compound of formula (I) according to the present invention or a photopolymerizable composition according to the present invention for use as a medicament.

The antibacterial properties deriving from the presence of quaternary ammonium functionality make the compound of formula (I) and the photopolymerizable composition according to the invention suitable for use in the medical field.

The structure and antibacterial properties deriving from the presence of the quaternary ammonium functionality make the compound of formula (I) particularly suitable for this use, even in fields other than the medical one.

Additional characteristics and advantages of the invention will appear more clearly from the following description of some of its preferred embodiments, given below by way of nonlimiting example with reference to the following exemplary examples.

A colony of bacterium taken from agar plate is inoculated in Brain Hearth Infusion medium (BHI) and grown overnight at <NUM>. The next day, the bacteria are diluted in fresh medium containing the phenol red indicator, up to a density of <NUM><NUM> bacteria/mL.

A stock solution of <NUM>/mL of compound is prepared in BHI medium containing phenol red.

In a <NUM>-well plate, the compound stock solution is diluted serially (the concentration is halved at each step) to obtain the following final concentrations after addition of the bacteria suspension: <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL. A compound-free medium is used as a growth control. A volume of bacterial suspension equal to <NUM>*<NUM><NUM> bacteria/mL is added to each well containing the compound and the control. The dish is incubated at <NUM> for <NUM> hours. Bacterial growth in each well is detected by the phenol red, which turns from red to yellow following acidification of the medium induced by bacterial metabolism. The lowest concentration of the compound causing no evident color change corresponds to the MIC.

A <NUM>/mL compound stock solution in BHI medium is prepared. In a <NUM>-well plate, the compound solution is diluted serially (the concentration is halved at each step) to obtain the following final concentrations after addition of the bacteria suspension: <NUM>/mL; <NUM>/mL; <NUM> /mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL; <NUM>/mL. Wells containing a mixture of penicillin and streptomycin antibiotics are used as a positive control. Compound-free medium is used as a growth control. A volume of bacterial suspension equal to <NUM>*<NUM><NUM> bacteria/mL is added to each well containing the compound and the controls. The dish is incubated at <NUM> for <NUM> hours. The lowest compound concentration at which no turbidity of the culture medium is evident is defined as MIC. For the calculation of MBC, aliquots equal to <NUM>µL are taken from the wells showing evident no turbidity of the medium and are plated on BHI agar plates for <NUM> hours. The MBC is calculated as the concentration of compound that did not produce bacterial colony growth on the dish. Bacterial suspensions taken from the positive control (growth medium only) and the negative control (growth medium with Ampicilin <NUM>µg/mL) are also seeded.

A test adapted from a commonly used method for determining the sensitivity of a bacterial strain to antibiotics in solution, known as Kirby-Bauer antibiotic testing or disc diffusion antibiotic sensitivity testing was used (<NPL>). The test performed involves the use of discs imbued with a known concentration of the substance under examination that are placed on a layer of bacteria grown on agar. The diffusion of the bactericidal molecule from the disk into the agar causes the inhibition of bacterial growth in the area surrounding the disk itself where the molecule has spread with the formation of what are called zones of growth inhibition. The diameter of these inhibition zones (transparent circular regions in comparison to the bacterial film) is proportional to the antibacterial efficacy of the molecule to its concentration and to its diffusion ability in the medium.

The DCT test is based on the turbidimetric determination of bacterial growth in <NUM>-well microplates.

On the wall of each well, <NUM>µL of the resin to be tested are polymerized for <NUM>, using a VALO® Grand LED curing light (Ultradent, Milan, Italy) in standard mode (<NUM> mW/cm<NUM>, <NUM> maximum of emission in the ranges of wavelengths <NUM>-<NUM> and <NUM>-<NUM>);
In this way the side walls of the wells are coated with the polymerized material under test. The wells are then washed with phosphate buffered saline (PBS) before inoculating them with bacteria. Keeping the plate in vertical position, <NUM>µL of S. Mutans bacterial suspension (ATCC <NUM>) in brain heart infusion medium (BHI) from an o/n culture, is then deposited on the layer of material present on the side walls of the wells. The plate is held upright for <NUM> hour to allow direct contact between bacteria and the cured material. <NUM>µL culture broth is then added to each of the wells with gentle mixing. The microplate is then placed in the chamber of a spectrophotometer for ELISA plates reading at <NUM> and the optical density in each well is measured at <NUM> at regular intervals (every <NUM> minutes for <NUM> hours). The whole experiment is conducted under aseptic conditions and is repeated on three microplates to ensure reproducibility of the result. <NUM> wells for each microplate were tested for each sample.

The degree of conversion (DC) was measured with a Fourier Transform Infra-Red Attenuated Total Reflectance equipment (FTIR-ATR, Nicolet <NUM>, Thermo Scientific, Milan, Italy).

The photopolymerization of the experimental adhesives took place according to the following protocol:.

To determine the µTBS value, human teeth not affected by caries or ruptures and without signs of previous restorations were used.

The protocol followed for the preparation of dental samples using the commercial total-etch Adper™ Scotchbond™ Multi-Purpose adhesive composed by the primer (Adper™ Scotchbond™ Multi-Purpose Primer) and the bonding (Adper™ Scotchbond™ Multi-Purpose Adhesive) (SBMP; <NUM>™ ESPE, St Paul, MN, USA) with <NUM>-step adhesion technique, is described below:.

The number of sticks obtained for each sample ranges from <NUM>-<NUM>.

The solutions for NMR analysis were prepared by dissolving a portion of material (<NUM>-<NUM>) in <NUM> of deuterated water (D<NUM>O, Sigma-Aldrich, <NUM>% D) or <NUM> of deuterated dimethyl sulfoxide (DMSO-d6, Sigma-Aldrich <NUM>% D). <NUM>-NMR (<NUM> scans), 13C-NMR (<NUM> scans), HH-Cosy (<NUM> scans), gHSQC (<NUM> scans) of the monomers were obtained at room temperature using a Varian <NUM> NMR (Nuclear Magnetic Resonance) spectrometer.

The analysis was carried out with a Fourier transform infrared spectrometer (Nicolet <NUM>, deterctor: DTGS KBr, Thermo scientific), equipped with a diamond ATR (Attenuated total reflectance). The background was recorded against air prior to the characterization of each monomer. A portion of solid monomer (<NUM>-<NUM>), non-derivatized and untreated, was placed on the ATR and pressed by a piston in order to ensure optimal contact. The transmittance (T%) spectrum was recorded in the <NUM>-<NUM>-<NUM> range, with <NUM> scans and <NUM>-<NUM> resolution.

<NUM> grams of <NUM>,<NUM>-dibromo dodecane and <NUM> of <NUM>-(dimethylamino)ethyl methacrylate in <NUM> of acetonitrile were added to a Schlenk-type reactor equipped with a magnetic stir bar. The reaction mixture was heated to <NUM> for <NUM> days obtaining via precipitation with ethyl ether and filtration <NUM> grams (<NUM>% yield) of the compound represented below in Formula (<NUM>)
<CHM>.

The compound prepared (herein and after also referred to as "DDM") was characterized by <NUM>-NMR, 13C-NMR, HH-Cosy, gHSQC obtained with NMR spectrometer (Nuclear Magnetic Resonance) Varian <NUM> and by FTIR-ATR analysis (Nicolet <NUM>, Thermo scientific), spectra are shown in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> respectively.

<NUM> grams of the compound represented in Formula (<NUM>) obtained through the procedure in Example <NUM>, are placed in <NUM> of water in a light-shielded Schlenk-type reactor equipped with a magnetic stir bar. <NUM> grams of silver fluoride (AgF) in <NUM> of water is added dropwise to the reactor. The reaction is left at room temperature for <NUM>. The raw product is filtered and lyophilized obtaining quantitatively the compound represented in Formula (<NUM>)
<CHM>.

The compound prepared (herein and after also referred to as "DDM-F") was characterized by <NUM>-NMR, 13C-NMR, 19F-NMR, HH-Cosy, gHSQC obtained with NMR (Nuclear Magnetic Resonance) Varian <NUM> spectrometer, spectra are shown in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> respectively.

<NUM> grams of <NUM>,<NUM>-dibromo dodecane and <NUM> of <NUM>-(dimethylamino)propyl methacrylamide in <NUM> of acetonitrile were added to a Schlenk-type reactor equipped with a magnetic stir bar. The reaction mixture was heated to <NUM> for <NUM> days obtaining via precipitation with ethyl ether and filtration <NUM> grams (<NUM>% yield) of the compound represented below in Formula (<NUM>)
<CHM>.

The prepared compound (herein and after also referred to as "DDMP") was characterized by <NUM>-NMR, 13C-NMR, HH-Cosy, gHSQC obtained with NMR spectrometer (Nuclear Magnetic Resonance) Varian <NUM> and by FTIR-ATR analysis (Nicolet <NUM>, Thermo scientific), spectra are shown in <FIG>, <FIG>, <FIG>, <FIG> and <FIG> respectively.

<NUM> grams of the compound represented in Formula (<NUM>) obtained through the procedure in Example <NUM>, are placed in <NUM> of water in a Schlenk type reactor shielded from light and equipped with a magnetic stir bar. <NUM> grams of silver fluoride (AgF) in <NUM> of water is added dropwise to the reactor. The reaction is left at room temperature for <NUM>. The raw product is filtered and lyophilized obtaining quantitatively the compound represented in Formula (<NUM>)
<CHM>.

The prepared compound (herein and after also referred to as "DDMP-F") was characterized by <NUM>-NMR, 19F-NMR, HH-Cozy, obtained with a NMR (Nuclear Magnetic Resonance) Varian <NUM> spectrometer, spectra are shown in <FIG>, <FIG>, and <FIG> respectively.

<NUM> grams of <NUM>,<NUM>-dibromo dodecane and <NUM> of <NUM>-(diethylamino)ethyl methacrylate in <NUM> of acetonitrile were added to a Schlenk-type reactor equipped with a magnetic stir bar. The reaction mixture was heated to <NUM> ° C for <NUM> days obtaining via precipitation from dichloromethane/ethyl ether and filtration <NUM> grams (<NUM>% yield) of the compound represented in Formula (<NUM>)
<CHM>.

The compound prepared (herein and after also referred to as "DDE") was characterized by <NUM>-NMR, 13C-NMR, HH-Cozy, gHSQC obtained with a NMR (Nuclear Magnetic Resonance) Varian <NUM> spectrometer and by FTIR-ATR analysis (Nicolet <NUM>, Thermo scientific), spectra are shown in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> respectively.

<NUM> grams of <NUM>,<NUM>-dibromo dodecane and <NUM> grams of <NUM>-amino-N, N-dimethylaniline in <NUM> of acetonitrile were added to a Schlenk-type reactor equipped with a magnetic stir bar. The reaction mixture was heated to <NUM> ° C for <NUM> days obtaining by precipitation with ethyl ether and filtration <NUM> grams (<NUM>% yield) of the compound represented below in Formula (<NUM>)
<CHM>.

The compound prepared (herein and after also referred to as "DDMAPMA") was characterized by <NUM>-NMR, 13C-NMR, HH-Cosy, gHSQC obtained with NMR (Nuclear Magnetic Resonance) Varian <NUM> and FTIR-ATR analysis (Nicolet <NUM>, Thermo scientific), spectra are shown in <FIG>, <FIG>, <FIG>, <FIG> and <FIG> respectively.

<NUM> grams of <NUM>,<NUM>-dibromo dodecane and <NUM> grams of N-(<NUM>-pyridylmethyl) methacrylamide in <NUM> of ethanol were added to a Schlenk-type reactor equipped with a magnetic stir bar. The reaction mixture was heated to <NUM> ° C for <NUM> days obtaining via precipitation with ethyl ether and filtration <NUM> grams (<NUM>% yield) of the compound represented below in Formula (<NUM>)
<CHM>.

The compound prepared (herein and after also referred to as "DDPyMMA") was characterized in terms of by <NUM>-NMR, 13C-NMR, HH-Cozy, gHSQC obtained with NMR (Nuclear Magnetic Resonance) Varian <NUM> spectrometer and by FTIR analysis. ATR (Nicolet <NUM>, Thermo scientific), spectra are shown in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> respectively.

<NUM> grams of <NUM>,<NUM>-dibromo xylene and <NUM> of <NUM>-(dimethylamino)ethyl methacrylate in <NUM> of acetonitrile were added to a Schlenk-type reactor equipped with a magnetic stir bar. The reaction mixture was left at room temperature (<NUM>) for <NUM> hours obtaining via precipitation with ethyl ether and filtration <NUM> grams (<NUM>% yield) of the compound represented below in Formula (<NUM>)
<CHM>.

The compound prepared (herein and after also referred to as "XyDM") was characterized in terms of by <NUM>-NMR, 13C-NMR, HH-Cozy, gHSQC obtained with NMR spectrometer (Nuclear Magnetic Resonance) Varian <NUM> and by FTIR analysis- ATR (Nicolet <NUM>, Thermo scientific), spectra are shown in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> respectively.

In order to test the antibacterial properties of the compounds prepared in Examples <NUM>-<NUM>, on colonies of S. Mutans (ATCC <NUM>), a bacterium commonly found in the human oral cavity, a test was set up to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) according to the "Determination of minimum inhibitory concentration (MIC)" methods and "Determination of minimum bactericidal concentration (MBC)" described above.

The results are reported in Table <NUM>.

The compounds according to Examples <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> were tested on bacterial strains different from S. Mutans with the same methods described above, obtaining the MIC and MBC values reported in Table <NUM>.

The compounds according to Examples <NUM>, <NUM>, <NUM>, and <NUM> were tested in order to evaluate their cytotoxicity on primary cells from human dental pulp according to the "Determination of cytotoxicity" method described above, obtaining the values reported respectively in the following Tables <NUM>, <NUM> ,<NUM>, and <NUM>. Cells were extracted from healthy third molars of patients after informed consent (Authorization Single Regional Committee FVG, study ID <NUM>, <NUM> August <NUM>). After extraction, the stem cell nature was ascertained by evaluating the expression of the positive markers CD <NUM>, CD <NUM>, CD <NUM> and the negative markers CD <NUM>, CD <NUM> and CD <NUM>.

From the obtained data, the compound according to Example <NUM> did not show significant signs of decrease in cell viability even at concentrations higher than the MIC and MBC, and therefore can also be used in contact with the oral mucosa.

From the obtained data, compound DDE according to Example <NUM> shown a maximum non-cytotoxic concentration (<NUM>µg/mL) higher than its MIC and MBC values against the analyzed bacteria strains, thereby confirming the suitability of the compound to be used also in contact with the oral mucosa.

The Applicant observed that the maximum tested non-cytotoxic concentration of the compound DDMAPMA according to Example <NUM> is higher than the respective MIC and MBC values (<NUM>-<NUM>µg/mL) against the analyzed bacteria strains, thereby confirming the suitability of the compound to be also used in contact with the oral mucosa.

The Applicant observed that for the compound DDPyMMA according to Example <NUM> the concentrations corresponding to the MIC and MBC values against the analyzed bacteria strains are lower than the maximum tested non-cytotoxic concentration (<NUM>µg/mL), thereby confirming the suitability of DDPyMMA for it use in contact with the oral mucosa.

In conclusion, from the data shown in Examples <NUM> and <NUM> it is possible to conclude that the compounds according to the invention show an adequate balance of antibacterial properties and cytotoxicity profile which allow their use in contact with the oral mucosa, especially in compositions for dental adhesives.

The bactericidal properties of the compounds according to Examples <NUM>, <NUM>, <NUM>, <NUM> and <NUM> were tested in various primer-type preparations, using the method "Bacterial inhibition determination - Agar diffusion test " described above. The disk soaked in the tested primer formulation without addition of compounds according to Examples <NUM>, <NUM>, <NUM>, <NUM> and <NUM> was used as a negative reference.

For the tests, the following primer-type formulations were used, identified by the following codes:.

Primer "L1" was diluted with <NUM>% by weight of solvent, water (H<NUM>O) or ethanol (EtOH) obtaining the following mixtures: <MAT> <MAT> and <MAT>.

Primer "L2" was diluted with <NUM>% by weight of solvent (water or ethanol) obtaining the following mixtures: <MAT> <MAT>.

Primer "R5" was diluted with <NUM>% by weight of solvent (water or ethanol) obtaining the following mixtures: <MAT> <MAT>.

Primer "Pa" was diluted with <NUM>% by weight of water obtaining the following final mixture: <MAT>.

Tables <NUM>, <NUM> e <NUM> show the obtained results.

For all three formulations of DDM primers, the greater the concentration of the monomer in solution, the higher the bactericidal action (a proportional increase in the range of inhibition of bacterial growth can be noted). Furthermore, the three different formulations containing the same concentration of monomer shown comparable bactericidal activity.

In general, the L1 and L2 primer formulations added with DDMP were found to be more efficient than those of R5 primers. Between them, the bactericidal action is overall comparable, although L1A shown a better effect.

In any case, the greater the concentration of the monomer in solution, the higher the bactericidal action (a proportional increase in the inhibition range of bacterial growth can be noted).

All three primer formulations with all <NUM> monomer types tested shown comparable bactericidal activity. The presence of a modest zone of inhibition even in the control of the acid primer formulation (PaA) is probably due to bacterial death induced by the acidification of the culture medium.

The bactericidal properties of the compounds according to Examples <NUM>, <NUM>, <NUM> and <NUM> within a reference bonding resin called R2 were tested using the "Direct contact test (DCT)" method described above. As a negative reference, the reference bonding resin was used without adding compounds according to the invention.

The reference resin called R2 has the following composition (% by weight):.

and was diluted with <NUM>% by weight of EtOH for use.

For the tests execution, different quantities of the compounds according to examples <NUM>, <NUM>, <NUM> and <NUM> were added to the resin R2 in a quantity range from <NUM> to <NUM>% by weight. The homogeneity of the material to be tested was ensured before application in the wells by carrying out a sonication (<NUM>%, <NUM>) and mixing with Vortex (<NUM> rpm, <NUM>) of the various resins added with the compound according to the invention.

<FIG> shows the optical density curves recorded during the tests conducted with the DDM compound according to Example <NUM>, added in concentrations of <NUM>%, <NUM>% and <NUM>% by weight to the resin R2 and, for comparison, the curve of optical density of the resin R2 alone.

As can be seen from the low optical density values found during the tests, the resin containing the DDM compound according to Example <NUM> was able to inhibit bacterial survival by contact even at the lowest concentration tested (<NUM>% by weight).

<FIG> shows the optical density curves recorded during the tests conducted with the DDE compound according to Example <NUM>, added in concentrations of <NUM>%, and <NUM>% by weight to the resin R2 and, for comparison, the density curve R2 resin optics alone.

As can be seen from the low optical density values found during the tests, also the resin containing the DDE compound according to Example <NUM> was able to inhibit bacterial survival by contact even at the lowest concentration tested (<NUM>% by weight).

<FIG> shows the optical density curves recorded during the tests conducted with the DDMAPMA compound according to Example <NUM>, added in concentrations of <NUM>%, and <NUM>% by weight to the resin R2 and, for comparison, the density curve R2 resin optics alone.

As can be seen, the resin containing the DDMAPMA compound according to Example <NUM> already at a concentration of <NUM>% by weight in the resin R2 was able to inhibit bacterial survival by contact.

<FIG> shows the optical density curves recorded during the tests conducted with the DDPyMMA compound according to Example <NUM>, added in concentrations of <NUM>, <NUM> and <NUM>% by weight to the resin R2 and, for comparison, the optical density curve of the R2 resin alone.

As can be seen, the resin containing the DDPyMMA compound according to Example <NUM> was able to inhibit bacterial survival by contact at a concentration of <NUM>% by weight in the R2 resin.

The ability of the compounds according to examples <NUM>, <NUM> and <NUM> to enter the polymer chain during photopolymerization, and therefore to act as antibacterial monomers, was tested using the "Determination of the degree of conversion (DC)" method described above. As a reference, the reference resin was used without adding compounds according to the invention.

The compounds were added in quantities of <NUM>% by weight to a reference resin called RT3 having the following composition:.

diluted with <NUM>% by weight of EtOH for use.

For the tests execution, the homogeneity of the material to be tested was ensured by carrying out a sonication (<NUM>%, <NUM>) and mixing with Vortex (<NUM> rpm, <NUM>) of the various resins added with the compound according to the invention.

<FIG> shows the comparison between the polymerization kinetics of the RT3 resin as such and with <NUM>% by weight of the compounds according to Examples <NUM>, <NUM>, and <NUM>. All three resins showed a value of DC% not significantly different from the reference resin, free of compounds according to the invention.

The ability of the compounds according to examples <NUM>, <NUM> and <NUM> to not affect the mechanical properties of the dental adhesives with which they are formulated, was tested using the method "Determination of the applied tensile strength (Microtensile Bond Strength - µTBS)" described above, by adding <NUM>% by weight of compounds according to the invention to the commercial adhesive Adper™ Scotchbond™ Multi-Purpose Adhesive (SBMP; <NUM> ™ ESPE, St Paul, MN, USA), according to the following procedure.

<NUM>% by weight of a compound according to Examples <NUM>, <NUM> and <NUM> was added to an exactly weighed quantity of SBMP inside a dark Eppendorf tube. The mixtures were sonicated (<NUM>%, <NUM>) and mixed with Vortex (<NUM> rpm, <NUM>) until complete solubilization of the tested compounds. Thus, <NUM> new adhesive systems were obtained which were tested in terms of tensile strength (Microtensile Bond Strength test - µTBS). The test was performed by placing the individual samples (sticks) in the appropriate slots for the microtensile tests with cyanoacrylate glue using the specifications reported in the guidelines of the Academy of Dental Materials for this test (<NPL>). In particular, the "active gripping" configuration was used with the aid of the Zapit glue (Dental Ventures of America, Corona, CA, USA;) and the "Microtensile tester" tool produced by Bisco Inc. , Schaumburg, IL , USA.

<FIG> shows the result of the tensile strength characterization tests carried out on the reference resin alone ("SBMP"), and on the resin added with <NUM>% by weight of the compounds according to examples <NUM>, <NUM> and <NUM> ("SBMP+<NUM>% DDE", "SBMP+<NUM>%DDMAPMA", and "SBMP+<NUM>% DDPyMMA") respectively.

The value of the tensile strength expressed in MPa is shown on the abscissa axis.

Claim 1:
A compound of formula (I):

        A-R<NUM>-B     (I)

wherein:
R<NUM> is selected from the group consisting of:
-(CH<NUM>)<NUM>-, and
<CHM>
and
A and B are independently selected from the group consisting of:
<CHM>
wherein:
R<NUM> and R<NUM> are independently selected from the group consisting of: methyl, ethyl, and n-propyl;
R<NUM> is selected from the group consisting of methylene, ethylene, n-propylene, and <NUM>,<NUM>-phenylene;
Y is selected from the group consisting of:
<CHM>
and
and <MAT> are independently selected from the group consisting of: F-, Cl-, and Br-.