Light, Visible

Example 18

Evaluation on Basic Properties of Compound (1-1-1)

[Absorption Properties]

An absorption spectrum was measured by preparing a 2.0×10⁻⁵ mol/L toluene solution of a compound (1-1-1) and measuring the absorption spectrum of the solution. As a result, the maximum absorption wavelength in a visible light region was 477 nm (FIG. 3).

[Light Emission Properties]

The fluorescence spectrum was measured by preparing a 2.0×10⁻⁵ mol/L toluene solution of a compound (1-1-1), which was used in the absorption spectrum, exciting the solution at an excitation wavelength of 365 nm at room temperature, and observing a fluorescence spectrum thereof. As a result, the maximum light emission wavelength was 483 nm, and the half width was 13 nm (FIG. 4). The fluorescence quantum yield in this example was 100%. Furthermore, the lifetime of a delayed fluorescence component was measured using a fluorescence lifetime measurement device and found to be 1.0 μsec. Note that, in the fluorescence lifetime measurement, fluorescence having a light emission lifetime of 100 ns or shorter was determined as instant fluorescence and fluorescence having a lifetime of 0.1 μs or longer was determined as delayed fluorescence, and data of 3.0 to 6.2 μsec was used for calculation of a fluorescence lifetime (FIG. 5).

Example 8

In order to elucidate the particle size dependence of the optical properties of nanomaterials, simulations have been performed using two models: the effective medium model (EMM) and finite element analysis+geometrical optics (FEA+GO). The simple EMM approach assumes that the nanoparticle has a single refractive index (n) and extinction ratio (k), and assumes that the particles are uniformly distributed throughout a low-refractive-index medium (FIG. 1A). The simulated spectrum (FIG. 1B) predicts a dramatic modulation of ca. 40% in the near-IR region of the electromagnetic spectrum using the optical constants of bulk VO₂ in the monoclinic (M1) and tetragonal phases. The simulation assumes a constant refractive index of ca. 1.5, which is typical of polymeric media. These results underscore the need for a uniform distribution of particles within a low-refractive-index matrix to achieve the desired NIR modulation. The FEA+GO simulations allow for a more detailed elucidation of particle-size-dependent optical properties. Spectra have been simulated for a composite with a fill factor of 3.7 wt. % of spherical VO₂ nanoparticles of varying diameters again assuming a temperature-independent refractive index of 1.5 for the polymeric media and the bulk optical constants for the insulating and metallic phases. As the diameter increases from 20 nm to 100 nm, the near-infrared modulation is observed to remain constant at ca. 40% (FIG. 1C). However, the visible light transmittance (at 680 nm) decreases from 80% to 68% for the low-temperature phase. When considering a composite of 100 nm long VO₂ wires with varying diameters, the 50 nm and 100 nm diameter wires show a variation of ca. 45% in the near-infrared, whereas the 20 nm wires show a modulation of ca. 40% (FIG. 1D). Although the NIR modulation is slightly diminished for the 20 nm diameter nanowires, they retain superior visible light transmittance. The substantial diminution in visible light transmittance with increasing particle is derived from the scattering background contributed by larger particles. Agglomeration of particles will to first order mimic the effects of having larger particles. These simulations indicate that the viability of utilizing VO₂ nanocrystals for effective thermochromic modulation will depend sensitively on their dimensions and their extent of dispersion.

Example 4

The antibacterial efficacy of unaltered and experimental (doped) dental adhesive resins against non-disrupted cariogenic (caries producing) biofilms was further assessed in terms of relative luminescence units (RLUs) using a real-time luciferase-based bioluminescence assay. Toward this end, experimental dental adhesive resins containing either N—TiO₂ NPs (5%-30%, v/v), N—F—TiO₂ NPs (30%, v/v) and N—Ag—TiO₂ NPs (30%, v/v) were synthesized by dispersing the nanoparticles in OBSP adhesive resin using a sonicator (4 cycles of 1 min, intervals of 15-sec between cycles; Q700, QSonica, USA). Two non-antibacterial (OBSP, and Scotchbond Multipurpose, 3M ESPE, USA) and one antibacterial (Clearfil SE Protect, Kuraray, Noritake Dental Inc., Japan) commercially available dental adhesive resins were also tested for antibacterial functionalities. Streptococcus mutans biofilms were grown (UA 159-ldh, JM 10; 37° C., microaerophilic) on the surfaces of disk-shaped specimens (n=18/group, d=6.0 mm, t=0.5 mm) for either 24 or 48 hours with or without continuous visible light irradiation (405±15 nm). One set of specimens was fabricated with OBSP and was treated with Chlorhexidine 2% (2 min) that served as our control group. Results for the antibacterial efficacies of both unaltered and experimental dental adhesive resins containing either doped or co-doped TiO₂ NPs under continuous visible light irradiation for either 24 or 48 hours, demonstrated that all groups tested displayed similar antibacterial behaviors under continuous visible light irradiation. Such findings suggest that under the conditions investigated (wavelength and power intensity), visible light irradiation had a very strong antibacterial behavior that took place independently of the antibacterial activity of the substrate where biofilms were grown (either antibacterial or not). Such impact made impossible the determination of the materials' real antibacterial efficacies under such light irradiation conditions.

Experiments were then conducted under dark conditions; bacteria were grown in dark conditions for either 24 and 48 hours. The results indicated that the TiO₂-containing adhesive resins were more antibacterial than commercially available non-antibacterial dental adhesive resins (such as OptiBond Solo Plus and Scotchbond Multipurpose). The experimental dental adhesive resins containing 30% (v/v) of nanoparticles (N—TiO₂ NPs, N—F—TiO₂ NPs and N—Ag—TiO₂ NPs) displayed antibacterial efficacies in dark conditions that were similar to Clearfil SE Protect (Fluoride-releasing material, Kuraray, Noritake Dental Inc., Japan). S. mutans biofilms grown on specimens treated with chlorhexidine 2% (2 min) displayed the lowest RLU values amongst all groups investigated, thereby confirming the strong antibacterial behavior of non-immobilized chlorhexidine. In addition, the antibacterial effect was demonstrated to be concentration-dependent, wherein experimental adhesive resins containing higher concentrations of antibacterial nanoparticles (either doped or co-doped) displayed stronger antibacterial effects against non-disrupted S. mutans biofilms. Since long intra-oral irradiation periods (24-hour and 48-hour) are impractical and clinically not feasible, associated with the fact that these materials are intended to be used in the oral cavity's dark conditions, these results were considered of paramount importance and clinically relevant for the commercialization pathway of recently developed antibacterial and bioactive nano-filled dental adhesive resins.

Optical and mechanical properties of both unaltered and experimental dental adhesive resins containing 5%-30% (v/v, 5% increments) of N—TiO₂ NPs were assessed in terms of color stability and biaxial flexure strength. Color stability (n=5) and biaxial flexure strength (n=8) specimens (d=6.0 mm, t=0.5 mm) were fabricated and tested using a color analysis software (ScanWhite, Darwin Syst., Brazil) and an Instron universal testing machine (cross-head rate=1.27 mm/min), respectively. Color stability measurements were performed immediately after specimen fabrication and after water storage (1, 2, 3, 4, 5, 6 months; 37° C.). The color stability results demonstrated that specimens fabricated using either unaltered or experimental dental adhesive resins containing N—TiO₂ NPs (5%-30%, v/v) were subjected to color changes induced by long-term water storage. The highest color variations were observed at two months of water storage (37° C.) for specimens pertaining to experimental groups containing either 5% or 10% of N—TiO₂ NPs. Specimens fabricated with unaltered OptiBond Solo Plus have demonstrated color variations that were similar to the color variations observed for the experimental group containing 20% N—TiO₂ NPs. Specimens fabricated with 30% N—TiO₂ NP-containing dental adhesive resins have shown the least amount of color variation throughout the investigation time (6-mo), and therefore, were considered as the most color stable amongst all materials investigated. From the esthetic standpoint, the human eye can only detect differences in color above a certain threshold (ΔE≥3).

In at least one embodiment, dental composition specimens fabricated with at 30% N—TiO₂ NPs displayed color variations that were either lower than or close to the human eye detection capability, thereby corroborating the long-term use of these highly esthetic experimental dental adhesive resins. In at least certain embodiments, the dental compositions contain at least 5% to 80% (v/v) of doped-TiO₂ NPs as disclosed herein, such as at least 5% (v/v), at least 6% (v/v), at least 7% (v/v), at least 8% (v/v), at least 9% (v/v), at least 10% (v/v), at least 11% (v/v), at least 12% (v/v), at least 13% (v/v), at least 14% (v/v), at least 15% (v/v), at least 16% (v/v), at least 17% (v/v), at least 18% (v/v), at least 19% (v/v), at least 20% (v/v), at least 21% (v/v), at least 22% (v/v), at least 23% (v/v), at least 24% (v/v), at least 25% (v/v), at least 26% (v/v), at least 27% (v/v), at least 28% (v/v), at least 29% (v/v), at least 30% (v/v), at least 31% (v/v), at least 32% (v/v), at least 33% (v/v), at least 34% (v/v), at least 35% (v/v), at least 36% (v/v), at least 37% (v/v), at least 38% (v/v), at least 39% (v/v), at least 40% (v/v), at least 41% (v/v), at least 42% (v/v), at least 43% (v/v), at least 44% (v/v), at least 45% (v/v), at least 46% (v/v), at least 47% (v/v), at least 48% (v/v), at least 49% (v/v), at least 50% (v/v), at least 51% (v/v), at least 52% (v/v), at least 53% (v/v), at least 54% (v/v), at least 55% (v/v), at least 56% (v/v), at least 57% (v/v), at least 58% (v/v), at least 59% (v/v), at least 60% (v/v), at least 61% (v/v), at least 62% (v/v), at least 63% (v/v), at least 64% (v/v), at least 65% (v/v), at least 66% (v/v), at least 67% (v/v), at least 68% (v/v), at least 69% (v/v), at least 70% (v/v), at least 71% (v/v), at least 72% (v/v), at least 73% (v/v), at least 74% (v/v), at least 75% (v/v), at least 76% (v/v), at least 77% (v/v), at least 78% (v/v), at least 79% (v/v), or at least 80% (v/v), with the balance comprising the curable adhesive resin material, and optionally other components as described elsewhere herein.

The present results demonstrate that experimental dental adhesive resins containing varying concentrations of N—TiO₂ NPs display biaxial flexure strengths that are either similar or better than the strength observed for specimens fabricated with the unaltered OBSP. No differences were observed among the flexure strengths of experimental groups, thereby indicating that the presently disclosed materials can behave very similar to commercially available materials when subjected to masticatory forces.

Specimens (d=6.0 mm, t=0.5 mm) of the unaltered resins and experimental dental adhesive resins containing 30% N—TiO₂ NPs, 30% N—F—TiO₂ NPs and 30% N—Ag—TiO₂ NPs were fabricated and characterized using the state of the art scanning electron microscope. This dual focused ion-beam microscope (Dual-FIB SEM/EDS) is capable, through a destructive process, to characterize and map the chemical composition and distribution of elements in three dimensions. The 3-D characterization and localization of components clearly demonstrated that experimental materials containing co-doped nanoparticles (e.g., 30% v/v, N—F—TiO₂ NPs) displayed an optimized dispersion of filler particles (part of the original composition) when compared to the filler particle distribution observed on specimens fabricated with the unaltered dental adhesive resin. The 3-D images demonstrated that the experimental adhesive resins had more filler particles per unit volume with a more homogeneous size distribution than the filler fraction and size distribution observed on OptiBond Solo Plus samples. In addition, results showed that larger and more agglomerated filler particles tend to result in a polymer matrix containing more pores per unit volume. This finding was corroborated by the pore-size distribution calculated for the unaltered samples and experimental dental adhesive resin samples, where it is possible to observe that the quantity and sizes of pores formed in experimental materials were smaller when compared to the unaltered OptiBond Solo Plus samples.

In at least one embodiment, the present disclosure includes a dental composition, comprising doped and/or coated TiO₂ NPs, and a curable resin material, wherein the curable resin material comprises a polymer precursor component. The TiO₂ NPs may comprise at least one dopant or coating selected from the group consisting of N (nitrogen), Ag (silver), F (fluorine), P (phosphorus), and PO₄ (phosphate). As noted above, in non-limiting embodiments, the dental composition may comprise a volume to volume ratio of doped TiO₂ NPs to curable resin material in a range of 1% to 80% (v/v), 5% to 50% (v/v), or 10% to 40% (v/v), for example. The polymer precursor component may be photocurable. The polymer precursor may be selected from the group consisting of acrylates, methacrylates, dimethacrylates, epoxies, vinyls and thiols. The polymer precursor may be selected from the group consisting of ethylenedimethacrylate (“EDMA”), bisphenol A glycidyl methacrylate (“BisGMA”), triethyleneglycol dimethacrylate (“TEGDMA”), 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane (UDMA), pyromellitic glycerol dimethacrylate (PMGDM), and 2-hydroxyethyl methacrylate (HEMA). The dental composition may comprise at least one solvent. The at least one solvent may be selected from the group consisting of water, ethanol, methanol, toluene, ethyl ether, cyclohexane, isopropanol, chloroform, ethyl acetate, acetone, hexane, and heptanes. The dental composition may comprise a polymerization initiator. The dental composition may comprise a filler. The dental composition may be selected from the group consisting of dental resins, dental bonding agents, dental adhesives, dental cements, dental restoratives, dentals coatings, dental sealants, acrylic resins, and denture teeth. The dental composition may comprise bioactive and/or antibacterial activity in the absence of visible or ultraviolet light. The dental composition may be used to form a hardened dental article after a photocuring step. In at least one embodiment, the disclosure includes an in vivo dental process, comprising applying the dental composition to at least one of a dental restorative and a dental substrate, and causing the dental restorative to be bonded to the dental substrate via the dental composition after a step of photocuring the dental composition.

Accordingly, the present disclosure is directed to at least the following non-limiting embodiments:

Clause 1. In at least one embodiment the present disclosure includes a dental composition, comprising doped TiO₂ nanoparticles, and a curable resin material, wherein the curable resin material comprises a polymer precursor component.

Clause 2. The dental composition of clause 1, wherein the doped TiO₂ nanoparticles comprise at least one dopant selected from the group consisting of N (nitrogen), Ag (silver), F (fluorine), P (phosphorus), and PO₄ (phosphate).

Clause 3. The dental composition of clause 1 or 2, wherein the doped TiO₂ nanoparticles further comprise at least one second dopant selected from the group consisting of N, Ag, F, P, and PO₄.

Clause 4. The dental composition of any one of clauses 1-3, comprising a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 1% to 80% (v/v).

Clause 5. The dental composition of any one of clauses 1-4, comprising a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 5% to 50% (v/v).

Clause 6. The dental composition of any one of clauses 1-5, comprising a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 10% to 40% (v/v).

Clause 7. The dental composition of any one of clauses 1-6, wherein the polymer precursor component is photocurable.

Clause 8. The dental composition of any one of clauses 1-7, wherein the polymer precursor is selected from the group consisting of acrylates, methacrylates, dimethacrylates, epoxies, vinyls and thiols.

Clause 9. The dental composition of any one of clauses 1-8, wherein the polymer precursor is at least one selected from the group consisting of ethylenedimethacrylate (EDMA), bisphenol A glycidyl methacrylate (BisGMA), triethyleneglycol dimethacrylate (TEGDMA), 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane (UDMA), pyromellitic glycerol dimethacrylate (PMGDM), and 2-hydroxyethyl methacrylate (HEMA).

Clause 10. The dental composition of any one of clauses 1-9, further comprising at least one solvent.

Clause 11. The dental composition of any one of clauses 1-10, further comprising a solvent selected from the group consisting of water, ethanol, methanol, acetone, toluene, ethyl ether, cyclohexane, isopropanol, chloroform, ethyl acetate, hexane, and heptanes.

Clause 12. The dental composition of any one of clauses 1-11, further comprising a polymerization initiator.

Clause 13. The dental composition of any one of clauses 1-12, further comprising a filler.

Clause 14. The dental composition of any one of clauses 1-13, wherein the curable resin material is selected from the group consisting of dental resins, dental bonding agents, dental adhesives, dental cements, dental restoratives, dentals coatings, dental sealants, acrylic resins, and denture teeth.

Clause 15. The dental composition of any one of clauses 1-14, comprising bioactive and/or antibacterial activity in the absence of visible or ultraviolet light.

Clause 16. A kit for forming a dental composition, the kit comprising doped TiO₂ nanoparticles, and a curable resin material, wherein the curable resin material comprises a polymer precursor component.

Clause 17. The kit of clause 16, wherein the doped TiO₂ nanoparticles comprise at least one dopant selected from the group consisting of N (nitrogen), Ag (silver), F (fluorine), P (phosphorus), and PO₄ (phosphate).

Clause 18. The kit of clause 16 or 17, wherein the doped TiO₂ nanoparticles further comprise at least one second dopant selected from the group consisting of N, Ag, F, P, and PO₄.

Clause 19. The kit of any one of clauses 16-18, comprising sufficient doped TiO₂ nanoparticles and curable resin material such that the dental composition comprises a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 1% to 80% (v/v).

Clause 20. The kit of any one of clauses 16-19, comprising sufficient doped TiO₂ nanoparticles and curable resin material such that the dental composition comprises a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 5% to 50% (v/v).

Clause 21. The kit of any one of clauses 16-20, comprising sufficient doped TiO₂ nanoparticles and curable resin material such that the dental composition comprises a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 10% to 40% (v/v).

Clause 22. The kit of any one of clauses 16-21, wherein the polymer precursor component is photocurable.

Clause 23. The kit of any one of clauses 16-22, wherein the polymer precursor is selected from the group consisting of acrylates, methacrylates, dimethacrylates, epoxies, vinyls and thiols.

Clause 24. The kit of any one of clauses 16-23, wherein the polymer precursor is at least one selected from the group consisting of ethylenedimethacrylate (EDMA), bisphenol A glycidyl methacrylate (BisGMA), triethyleneglycol dimethacrylate (TEGDMA), 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane (UDMA), pyromellitic glycerol dimethacrylate (PMGDM), and 2-hydroxyethyl methacrylate (HEMA).

Clause 25. The kit of any one of clauses 16-24, further comprising at least one solvent.

Clause 26. The kit of any one of clauses 16-25, further comprising a solvent selected from the group consisting of water, ethanol, methanol, acetone, toluene, ethyl ether, cyclohexane, isopropanol, chloroform, ethyl acetate, hexane, and heptanes.

Clause 27. The kit of any one of clauses 16-26, further comprising a polymerization initiator for combining with the doped TiO₂ nanoparticles, and curable resin material.

Clause 28. The kit of any one of clauses 16-27, further comprising a filler for combining with the doped TiO₂ nanoparticles, and curable resin material.

Clause 29. The kit of any one of clauses 16-28, wherein the curable resin material is selected from the group consisting of dental resins, dental bonding agents, dental adhesives, dental cements, dental restoratives, dentals coatings, dental sealants, acrylic resins, and denture teeth.

Clause 30. The kit of any one of clauses 16-29, wherein the dental composition has bioactive and/or antibacterial activity in the absence of visible or ultraviolet light.

Clause 31. A hardened dental article formed from the dental composition of any one of clauses 1-15, after the dental composition has been photocured.

Clause 32. An in vivo dental process, comprising: applying a dental composition to a dental surface, the dental composition comprising doped TiO₂ nanoparticles, and a curable resin material, wherein the curable resin material comprises a polymer precursor component; and causing the dental composition to be bonded to the dental surface by photocuring the dental composition.

Clause 33. The dental process of clause 32, wherein the dental surface is at least one of a dental restorative and a dental substrate.

Clause 34. The dental process of clause 32 or 33, wherein the doped TiO₂ nanoparticles comprise at least one dopant selected from the group consisting of N (nitrogen), Ag (silver), F (fluorine), P (phosphorus), and PO₄ (phosphate).

Clause 35. The dental process of any one of clauses 32-34, wherein the doped TiO₂ nanoparticles further comprise at least one second dopant selected from the group consisting of N, Ag, F, P, and PO₄.

Clause 36. The dental process of any one of clauses 32-35, wherein the dental composition comprises a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 1% to 80% (v/v).

Clause 37. The dental process of any one of clauses 32-36, wherein the dental composition comprises a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 5% to 50% (v/v).

Clause 38. The dental process of any one of clauses 32-37, wherein the dental composition comprises a volume to volume ratio of doped TiO₂ nanoparticles to curable resin material in a range of 10% to 40% (v/v).

Clause 39. The dental process of any one of clauses 32-38, wherein the polymer precursor component is photocurable.

Clause 40. The dental process of any one of clauses 32-39, wherein the polymer precursor is selected from the group consisting of acrylates, methacrylates, dimethacrylates, epoxies, vinyls and thiols.

Clause 41. The dental process of any one of clauses 32-40, wherein the polymer precursor is at least one selected from the group consisting of ethylenedimethacrylate (EDMA), bisphenol A glycidyl methacrylate (BisGMA), triethyleneglycol dimethacrylate (TEGDMA), 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane (UDMA), pyromellitic glycerol dimethacrylate (PMGDM), and 2-hydroxyethyl methacrylate (HEMA).

Clause 42. The dental process of any one of clauses 32-41, wherein the dental composition further comprises at least one solvent.

Clause 43. The dental process of any one of clauses 32-42, further comprising a solvent selected from the group consisting of water, ethanol, methanol, acetone, toluene, ethyl ether, cyclohexane, isopropanol, chloroform, ethyl acetate, hexane, and heptanes.

Clause 44. The dental process of any one of clauses 32-43, wherein the dental composition further comprises a polymerization initiator.

Clause 45. The dental process of any one of clauses 32-44, wherein the dental composition further comprises a filler.

Clause 46. The dental process of any one of clauses 32-45, wherein the curable resin material is selected from the group consisting of dental resins, dental bonding agents, dental adhesives, dental cements, dental restoratives, dentals coatings, dental sealants, acrylic resins, and denture teeth.

Clause 47. The dental process of any one of clauses 32-46, wherein after curing, the dental composition has bioactive and/or antibacterial activity in the absence of visible or ultraviolet light.

Clause 48. The dental process of any one of clauses 32-47, wherein the dental surface has been acid-etched prior to the application of the dental composition thereon.

While the present disclosure has been described herein in connection with certain embodiments so that aspects thereof may be more fully understood and appreciated, it is not intended that the present disclosure be limited to these particular embodiments. On the contrary, it is intended that all alternatives, modifications and equivalents are included within the scope of the present disclosure as defined herein. Thus the examples described above, which include particular embodiments, will serve to illustrate the practice of the inventive concepts of the present disclosure, it being understood that the particulars shown are by way of example and for purposes of illustrative discussion of particular embodiments only and are presented in the cause of providing what is believed to be the most useful and readily understood description of procedures as well as of the principles and conceptual aspects of the present disclosure. Changes may be made in the formulation of the various compositions described herein, the methods described herein or in the steps or the sequence of steps of the methods described herein without departing from the spirit and scope of the present disclosure. Further, while various embodiments of the present disclosure have been described in claims herein below, it is not intended that the present disclosure be limited to these particular claims.