"DENTAL COMPOSITE FORMULATIONS"

FIELD OF INVENTION

[001] The embodiments herein relate to polymeric biomaterials more specifically for restorative dentistry, broadly to a composition for an organic resin matrix which can be used for cementation of implants, endodontic sealers, root repair materials, root end filling materials and luting cements.

BACKGROUND OF INVENTION

[002] Polymeric biomaterials are used in Dental composites as restorative material or adhesives. The dental composites are widely used for filling cavity preparations, filling gaps between teeth, minor reshaping of teeth, and as inlays or onlays.

[003] Traditionally, amalgam was the preferred choice as a dental restorative material owing to its low cost, ease of application, strength, durability, and longevity. However, amalgam is no more the preferred choice as it poses many disadvantages. Problems associated with the amalgam include environmental pollution, toxicity of mercury, and aesthetic concerns.

[004] In recent years, the dental composites are used as an alternative to the amalgam. Typically, the dental composites consists of organic resin based matrix and a filler. The organic resin based matrix mostly includes a bisphenol A-glycidyl methacrylate (Bis-GMA) or urethane dimethacrylate (UDMA). Most commonly used fillers are silica-based.

[005] Bis-GMA and UDMA are highly viscous at room temperature and difficult to work with. The organic resin matrix further includes lower viscosity polymerizable component ( "fluid izer"), a methacrylate monomer, such as a tetraethylene glycol dimethacrylate (TEGDMA) or a docecanediol dimethacrylate. However, while providing low viscosity, lower viscosity components (generally low molecular weight monomers) can contribute to increased shrinkage, greater elution of cytotoxic components, and potential tissue damage. The shrinkage can lead to gaps between the filling and the tooth thereby allowing bacteria to enter and may cause secondary caries or pulpitis. Additionally, other problems associated with dental composites are development of stress on the teeth due to unyielding matrix during polymerization shrinkage. Moreover, the dental conposites are bonded to the teeth using intermediary low filled or unfilled diluents containing bonding agents. These diluents may contribute to a greater elution and cytotoxicity and increases the potential interfaces in a tooth-restoration unit. These interfaces may leak leading to bacterial ingress into dental soft tissues like pulp and the aforementioned effects.

[006] Thus, there is a need for a composition of a dental composite which exhibit improved aesthetics yet provide high degree of conversion, low elution, self-adhesive ability, low polymerization shrinkage, low cytotoxicity, and low-post operative sensitivity.

OBJECT OF THE INVENTION

[007] The principal object of the embodiments herein is to provide a composition for organic resin matrix and filler modification for polymeric biomaterials.

[008] Another object of the embodiments herein is to provide a composition for dental composites.

SUMMARY

[009] Accordingly the embodiments herein provide a composition for dental composites. The dental composites includes an organic resin matrix, wherein the organic resin matrix includes silicone macromer resins, polymerizable monomers, adhesive monomers, photo initiators, accelerators, and photoacid catalysts. The organic resin matrix includes a hybrid of two Macromer resins "a" and "c". The Macromer resin "a" also referred as first silicone macromer includes at least one of polysiloxane having Methacrylate terminal group. In another embodiment, Macromer resin "c" also referred as second silicone macromer includes at least one ofpolysiloxane having cyclic epoxy group.

[0010] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description. It should be understood, however, that the following description, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] This invention is illustrated in the accompanying drawings. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0012] FIGS. 1A and I B are block diagrams representing generally, among other things, constituents of an organic resin matrix, according to an embodiment as disclosed herein;

[0013] FIGS. 2A to 2D are example graph depicting rate of elution of experimental dental organic matrix and conventional dental organic matrix stored in an artificial saliva medium for 24 hours, according to an embodiment as disclosed herein;

[0014] FIGS. 2E to 2G are example graph depicting rate of elution of experimental dental organic matrix and conventional dental organic matrix stored in an absolute alcohol medium for 24 hours, according to an embodiment as disclosed herein;

[0015] FIG. 3A is a example graph depicting cytotoxicity levels in experimental dental organic resin matrix and conventional dental organic resin matrix, according to an embodiment as disclosed herein;

[0016] FIG. 3B is a example graph depicting cytotoxicity levels in experimental dental composites and conventional dental composites, according to an embodiment as disclosed herein;

[0017] FIG. 4A represents absorption mode FTIR recorded with ATR of conventional resin based matrix N5 (BT) after polymerization, according to an embodiment as disclosed herein;

[0018] FIG. 4B represents absorption mode FTIR recorded with ATR of conventional resin based matrix N5 (BT) before polymerization, according to an embodiment as disclosed herein;

[0019] FIG. 4C represents absorption mode FTIR recorded with ATR of experimental resin based matrix N4 (E) after polymerization, according to an embodiment as disclosed herein;

[0020] FIG. 4D represents absorption mode FTIR recorded with ATR of experimental resin based matrix N4 (E) before polymerization, according to an embodiment as disclosed ; herein;

[0021] FIG. 4E represents absorption mode FTIR recorded with ATR of experimental resin based matrix N3 (G) after polymerization, according to an embodiment as disclosed herein;

[0022] FIG. 4F represents absorption mode FTIR recorded with ATR of experimental resin based matrix N3 (G) before polymerization, according to an embodiment as discfosed herein;

[0023] FIG. 4G represents absorption mode FTIR recorded with ATR of experimental resin based matri 2 (T) after polymerization, according to an embodiment as disclosed herein; [0024] FIG. 4H represents absorption mode FTTR recorded with ATR of experimental resin based matrix N2 (T) before polymerization, according to an embodiment as disclosed herein;

[0025] FIG. 41 represents absorption mode FTIR recorded with ATR of Experimental resin based matrixNl (U) after polymerization, according to an embodiment as disclosed herein;

[0026] FIG. 4J represents absorption mode FΉR recorded with ATR of Experimental resin based matrix Nl (U) before polymerization, according to an embodiment as disclosed herein;

[0027] FIG. 5A is an example FTIR-ATR graph of un-polymerized materials showing peak areas under 1638 aliphatic C=C vibration for the organic matrix based composite 1 U and control matrix based composite 5BT, according to an embodiment as disclosed herein;

[0028] FIG. 5B is an example FTIR-ATR graph of un-polymerized materials showing peak areas under 1638 aliphatic C=C vibration for the organic matrix based composite 1 U and control commercial composite 8C, according to an embodiment as disclosed herein;

[0029] FIG. 5C is an example FTIR-ATR graph of un-polymerized materials showing peak areas under 1638 aliphatic C=C vibration for the organic matrix based composite 1 U and control commercial composite 7R, according to an embodiment as disclosed herein;

[0030] FIG. 5D is an example FTIR-ATR graph of un-polymerized materials showing the peak area under 880 oxirane vibration for the organic matrix based composite 1U and control commercial composite 6S, according to an embodiment as disclosed;

[0031] FIG. 6 is a graph depicting micro-tensile bond strength of the experimental organic matrix based four composites U, G, E, T and conventional dental composite bonded without any adhesive and two commercial composites bonded with known adhesives and a control commercial self-adhesive restorative cement on human teeth, according to an embodiment as disclosed herein;

[0032] FIG. 7 is an example graph depicting dimensional change of composites during polymerization measured at different instants showing expansion and shrinkage of the experimental and conventional dental composites, according to an embodiment as discbsed herein;

[0033] FIG. 8 A is an example ΡΉΙ -ΑΤΙ graph showing lack of oxygen inhibition in the experimental organic matrix containing composite 1U unlike internal standard control composite 5BT at 2mm thickness, according to an embodiment as disclosed herein;

[0034] FIG. 8B is an example ΡΉΚ-ΑΉ graph showing lack of oxygen inhibition in the experimental organic matrix containing composite 1U unlike control commercial composite 8C at 4 mm thickness, acco rd ing to an e mbod ime nt as d isc lo sed here in;

[0035] FIG. 8C is an example FTIR-ATR graph showing lack of oxygen inhibition in the experimental organic matrix containing composite 1U unlike internal standard control composite 5BT at 4mm thickness, according to an embodiment as disclosed herein;

[0036] FIG. 8D is an example F R-ATR graph showing lack of oxygen inhibition in the experimental organic matrix containing composite 1 U unlike control commercial composite 7R at 2mm thickness, according to an embodiment as disclosed herein;

[0037] FIG. 8E is an example FΉR-ATR graph showing lack of oxygen inhibition in the experimental organic matrix containing composite 2G unlike control commercial composite 8C at 2mm thickness, according to an embodiment as discbsed herein;

[0038] FIG. 8F is an example FHR-ATR graph showing lack of oxygen inhibition in the experimental organic matrix containing composite 3E unlike control commercial composite 8C at 2mm thickness, according to an embodiment as disclosed herein;

[0039] FIG. 8G is an example ΡΉΚ-ATR graph showing lack of oxygen inhibition in the experimental organic matrix containing composite 3E unlike internal standard control composite 5BT at 2mm thickness, according to an embodiment as disclosed herein; and

[0040] FIG. 8H is an example ΡΉΚ-ATR graph showing lack of oxygen inhibition in the organic experimental matrix containing composite 3E unlike control commercial composite 7R at 2mm thickness, according to an embodiment as discbsed herein.

DETAILED DESCRIPTION OF THE INVENTION

[0041] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non- limiting embodiments that are detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0042] Throughout the description any instance of reference to "experimental dental composite" anywhere in the specification refers to a "dental composite". Further, throughout the description any instance of reference to "experimental dental resin matrix" anywhere in the specification refers to "organic dental resin matrix".

[0043] The embodiments herein provide a composition of an organic resin matrix for polymeric biomaterials. Further, embodiments herein provide a composition for dental composites. The properties of said dental composites include lo w elution, low cytotoxicity, high degree of conversion, no shrinkage, low-post operative sensitivity, no oxygen inhibition, and self-adhesive ability.

Composition of the organic resin matrix

[0044] The embodiments herein provide a composition for organic resin matrix, wherein the organic resin matrix includes Silicone macromer resins, polymerizable monomers, adhesive monomers, photo initiators, accelerators, and photoacid catalysts.

Macromer resins [0045] The organic resin matrix includes two Macromer resins "a" and "c" as shown in FIG 1. In an embodiment, Macromer resin "a" also referred as first silicone macromer includes at least one of polysiloxane having Methacrylate group. However, it should be noted that any other methacrylate group can be substituted for the mono methacryloxy propyl group terminated polysiloxane described. In another embodiment, Macromer resin "c" also referred as second silicone macromer includes at least one of polysiloxane having cyclic Epoxy group. However, it should be noted that any other cyclic ring opening polymerizable group can be substituted for the Epoxy cycto hexyl ethyl terminated polysiloxane described.

Functional moieties of Macro me rs

[0046] The Macromer resin "a" has a first functional moiety "b" and Macromer resin "c" has a second functional moiety "d" as shown in the FIG. 1. In an embodiment, the first functional moiety "b" includes at least one of a free-radical polymerizable Methacrylate group and the second functional moiety "d" includes at least one of a ring-opening polymerizable cyclic Epoxy group.

Polynieriz ble monomers

[0047] The polymerizable monomers are represented as "e", "f ' and "g" as shown in the FIG. 1. In an embodiment, "e" is any one of the many dimethacrylates available, "f is BisGMA and "g" is TEGDMA. In another embodiment, polymerizable monomers are in the range of 10% to 18%.

Adhesive

[0048] The adhesive is used to impart self-adhesive property. In an embodiment, acidic ester, aliphatic tetra carboxylic acid, and a hydrophilic monomer in a tertiary butanol vehicle are included to impart self-adhesive property. In an embodiment, the adhesive can be used within a range of 2% to 4%.

Photoinitiators, Accelerators and Photoacid catalysts

[0049] The photoinitiators, accelerators, and photo acid catalysts are used to facilitate polymerization. In one embodiment, the photoinitiator includes dketone. In one embodiment, the accelerator includes hydrogen donor. In one embodiment, the photoacid catalysts include a photoacid. In one embodiment, the photoinitiator, accelerator, and photoacid catalyst group can be within a range o f 1 % to 2%.

[0050] In one embodiment as shown in the FIG. I B, the experimental dental composite includes the composition of Silicone Macromer "c" ranging between 7-15%, Silicone Macromer "a" ranging between 5-10%, at least one Dimethacrylate "e" ranging between 1-3%, BisGMA "f ranging between 7-9%, TEGDMA "g" ranging between 3-5%, Aliphatic tetra carboxylic acid ranging between 0.32-0.4%, Hydrophilic monomer ranging between 0.32-0:4%, Acidic ester ranging between 0.12-0.24%, Photosensitizer ranging between 0.2 -0.4%, Photoinitiator ranging between 0.2 -0.4%, Photoacid generator ranging between 0.12-0.24%, Hydrogen donor ranging between 0.2 -0.4%, Vehicle/solvent ranging between 0.32-0.4%, and Filler ranging between 65- 75%.

Preparation of the Organic Resin Matrix

[0051] The resin matrix undergoes polymerization by free radical induced addition polymerization and cationic ring opening polymerization concurrently. In an embodiment, during co-polymerization, the terminal groups of hybridized silicone macromers resin react with the monomers as shown in the FIG. 1A. The constituents are mixed in a cyclic mixer to obtain a homogeneous product. To the resulting homogenous product, 1 % to 2% dftcetone, photoacid and a hydrogen donor are added and mixed in a cyclic mixer and stored in a brown/black container. Furthermore, 1 % to 2% of acidic monomer like dipentaerythritol pentaacrylate phosphoric acid ester (PENTA), acid like butane tetracarboxylic acid, and hydrophilic monomer like hydro xyethyl methacrylate (HEMA) in a tertiary butanol vehicle are added to obtain the final matrix mixture.

Composition for Dental Composite

[0052] Further, the embodiments herein provide a composition for dental composites, wherein the organic resin matrix is combined with unsilanized filler. In an embodiment, the composition includes 20-35% of organic resin matrix and 65-80% of unsilanized filler. In an embodiment, the unsilanized filler includes Quartz, silica, and glass. In an embodiment, the dental composite comprised 30% of the prepared organic resin matrix and 70% unsilanized Quartz filler.

Dental Composites exhibiting enhanced Physical Properties and Biological Response

[0053] The dental composites including the aforementioned composition exhibit enhanced physical properties and biological response such as low elution, low cytotoxicity, high degree of conversion, no shrinkage, low-post operative sensitivity, and self-adhesive ability.

[0054] The low elution of undesirable substances such as Bisphenol A (BP A), BADGE, Bis DMA, Bis GMA corresponds to a better matrix and composite as shown in the FIGS. 2A, 2B, and 2C (in artificial saliva medium) and FIGS. 2E, 2F (in alcohol medium). Whereas, high elution of undesirable substance such as Bisphenol A (BPA) corresponds to an undesirable matrix as shown in the FIG. 2D (in artificial saliva medium) and the FIG. 2G (in alcohol medium).

[0055] The low cytotoxicity of the dental composite is a resultant of low elution of undesirable substances. The low cytotoxicity is observed in experimental dental composite and relatively high cytotoxicity is observed in conventional dental composites as shown in the FIG. 3B.

[0056] Degree of conversion refers to degree of polymerization. It refers to the percentage of monomer units being converted to polymers. The degree of conversion was highest in experimental resin matrix N4 as shown in the FIG. 4C and least in conventional resin matrix N5 as shown in the FIG 4 A.

[0057] The shrinkage upon polymerization can cause high internal stress. The conventional matrix may undergoes only free radical polymerizati n wherein, linear molecules come together during polymerization, by pulling the mass together, thus occupying less space post-polymerization than pre-polymerization and causes significant volumetric shrinkage. Conventional matrix monomers have low molar volume and more number of reactive double bonds that converts to single bonds during polymerization. Whereas the experimental hybrid macromer-dimethacrylate copolymerized matrix has very high molar volume and fewer double bonds that convert to single bonds during polymerization. The molar volume of one typical embodiment explained hereinabove is approximately 30 times more than the conventional matrix. However the viscosity is much less compared to the conventional matrix monomers. Further, the experimental matrix undergoes cationic ring opening addition polymerization in addition to free radical polymerization, wherein the ring molecule opens up for polymerization reaction, it occupies more space post-polymerization than pre-polymerization. Since the free radical polymerizable monomers are used in less quantity as the macromer hybrid has low viscosity and easy to handle, the shrinkage would be much lower. Further, polymerizatbn stress is reduced in the experimental materials as the matrix is uncoupled from the unyielding fillers and thus is more free to move. Unlike conventional materials, whose matrices are bound tightly to fillers through coupling agents.

[0058] The dental composites showed self adhesive ability due to addition of adhesives such as acidic ester, acid, and a hydrophilic monomer in a tertiary butanol vehicle. Also, the absence of strong dehydrating agent such as acetone reduces the post-operative sensitivity.

Comparison Tests

[0059] A few comparison tests have been conducted to showcase the properties and enhanced biological response of the novel organic resin matrix such as low elution, low cytotoxicity, high degree of conversion, no shrinkage, low-post operative sensitivity, no oxygen inhibition, and self-adhesive ability.

Example 1

[0060] Objective: To study rate of elution in conventional matrix and experimental matrix.

[0061] Comparison tests were conducted to check the rate of elution in the conventional matrix and the experimental matrix.

[0062] Elution tests were conducted in artificial saliva medium (aging medium) and absolute alcohol (ethanol as aging medium). High peak corresponds to greater elution.

[0063] In the FIGS. 2A to 2F, x-axis indicates time taken for elution (in minutes) and y- axis indicates magnitude of elution in microabsorbence units.

In artificial saliva medium (aging medium):

[0064] The experimental composite matrix (N2) showed the least elution as shown in the FIG. 2B and the conventional resin matrix (OBT) showed the highest elution as shown in FIG. 2D. The elution rate in the artificial saliva medium is as follows:

OBT > N3 > N2 > Nl In absolute alcohol (ethanol as aging medium):

[0065] The experimental organic matrix (Nl) showed the least elution as shown in the FIG. 2E and the conventional matrix (OBT) showed the most elution as shown in the FIG. 2G. The elution rate in the absolute alcohol medium is as follows:

OBT > N3 > Nl

Example 2

[0066] Objective; To study cytotoxicity levels in the conventional resin matrix and the experimental resin matrix.

[0067] Comparison tests were conducted to check the cytotoxicity levels in the conventional resin matrix and the experimental resin matrix.

[0068] The FIG. 3A represents cytotoxicity levels in the experimental dental organic matrix and the conventional organic matrix. The experiment was conducted in BH 21 and MG 63 cell lines.

[0069] In the FIG. 3A, x- axis indicates different groups of organic resin matrices and y- axis indicates cell- viability in percentage.

[0070] Cell viability is greatly affected by the organic resin matrix part of the composite greatly rather than the inorganic (filler) part. Thus, the tests were conducted for the matrices separately and composites (matrix + filler) separately.

[0071] The experimental organic resin matrix showed optimum cell viability in both BHK21 and MG63 cell lines. The conventional organic resin matrix showed excessive proliferation of cells leading to abnormal growth of cells which could translate to undesirable hyperplasia greater than the negative control which could probably be due to expression of proliferating cellular nuclear antigen (PCNA) as a result of elution of BisPhenol A. [0072] In the FIG. 3B, x- axis indicates different group of experimental composites (organic matrix and filler) and the conventional composite (organic matrix and filler) and y-axis indicates cell- viability in percentage. The experiment was conducted on a primary Mes (Mes is a code used in the experiment for Human mesenchymal stem cells) and a permanent cell line BHK 21 using Trypan Blue exclusion dye staining Flow cytometric counting (TB) and mitochondrial assay (MTT) respectively. The experimental composite showed greater cell viability compared to the conventional composites SN (silorane based composite Filtek P90), RF (BisGMA-TEGDMA based composite Restofill) and CX (Polysiloxane-Dimethacrylate based composite Ceram X) in both the cell lines. Thus, greater cell viability corresponds to lower cytotoxicity.

Example 3

[0073] Objective: To study the degree of conversion in the conventional matrix and the experimental matrix.

[0074] Comparison tests were conducted to check the degree of conversion in the conventional matrix and the experimental matrix.

In the FIG. 4A to 4J, x-axis indicates the wave number (cm ^"1 ) and the y-axis indicates the absorbance.

[0075] The degree of conversion of the sample was estimated using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy.

[0076] Degree of conversion in Conventional Matrix was calculated using the formula: The areas under the relevant peaks as given in the formulae below are measured and calculated

\C = C aliphatic (1638) / C = C aromatic (1608Vn polymerized re sin composite)

DC% = \- -r — '- -L t ' _{x l00}

\C = C aliphatic (1638) / C = C aromatic (1608)w unpofymerized resin composite) [0077] Degree of conversion in Experimental Matrix was calculated using the formula:

Methacrylate region:

(c = C aliphatic (1638) / C = C aromatic (l ₆ 08)in polymerized re sin composite)

| DC% = 1 x lOO

(C = C aliphatic (1638) /C = C aromatic (1608);« unpolymerized re sin composite)

Oxirane region:

{pxirane (880) I C - H (1254) « polymerized re sin composite

DC% = 1 - x lOO

{oxirane (880) / C - H (1254)/ ^' « unpolymerized re sin composite

l it uic x ucgi cc ui vuiiv c i aum ui CA c i i incii iiii uian ices (N1-N4) and conventional matrix (N5)

Nl (U) : represents Urethane dimethacrylate (UDMA)

N2 (T) : represents Triethylene glycol dimethacrylate (TEGDMA)

N3 (G) : represents Bisphenol A glycidyl methacrylate (Bis-GMA)

N4 (E) : represents Ethoxylatedbisphenol A dimethacrylate (BisEMA)

N5 (BT) : represnts conventional matrix (Bis GMA- TEGDMA)

[0079] From the table below, it is apparent that the degree of conversion is higher in the experimental matrix compared to the conventional matrix. Further, the highest degree of conversion was observed with experimental matrix N4 (E) as shown in the FIG. 4C followed by experimental matrix N3 (E) as shown in FIG. 4E, Nl (E) as shown in the FIG. 41, N2 (E) as shown in the FIG. 4G and lowest degree of conversion was observed in conventional matrix (N5) as shown in the FIG. 4A.

N3(G) 81.49 (4.808)

N4(E) 95.49 (7.092)

N5(BT) 39.62 (6.864)

Example 4

[0080] Objective: To study the concentration of polymerizable components in the conventional matrix and the experimental matrix.

[0081] Comparison tests were conducted to check the concentration of polymerizable components in the conventional matrix and the experimental matrix.

[0082] FIG. 5A represents concentration levels of polymerizable components in the experimental dental composites and the conventional composites.

[0083] In the FIGS. 5A to 5D, x-axis indicates wave number in (cm ^"1 ) and y- axis indicates absorbance.

[0084] The experimental composite matrix (1U) showed the least concentration of 0.016 while the control matrix based composite 5BT showed the highest concentration of 0.288 for FTIR-ATR of un-polymerized materials under the peak area 1638 aliphatic C=C vibration as shown in the FIG. 5A.

[0085] Further, the experimental composite matrix (1 U) showed the least concentration of 0.016 while the control commercial composite 8C showed the highest concentration of 0.192 for FTIR-ATR of un-polymerized materials under the peak area 1638 aliphatic C=C vibration as shown in the FIG. 5B.

[0086] Similarly, the experimental composite matrix (1 U) showed the least concentration of 0.016 while the control commercial composite 7R showed the highest concentration of 0.271 for FTIR-ATR of un-polymerized materials under the peak area 1638 aliphatic C=C vibration as shown in FIG. 5C.

[0087] In the FIG. 5D, the experimental composite matrix (1 U) showed the least concentration of 0.025 while the control commercial composite 6S showed the highest concentration of 0.273 for ΡΉΚ-ATR of un- polymerized materials under the peak area under 880 oxirane vibration as shown in the FIG. 5D.

[0088] In the above the FIGS. 5A to 5D, the area under peak indicates the concentration of a. particular group in the compound tested. From the above FIGS it is evident that the experimental composite occupies lesser area under the peak. Lesser is the area under the peak, lesser is the concentration.

Example 5

[0089] Objective: To study the rate of micro-tensile bond strength in the conventional composite and the experimental composite.

[0090] Comparison tests were conducted to check the micro-tensile bond strength in the conventional composite and the experimental composite.

[0091] FIG. 6 represents the micro- tensile bond strength levels in the experimerititl dental composites and the conventional composites.

[0092] In FIG. 6, x-axis indicates stress applied in Pa and y- axis indicates the experimental dental composites and the conventional composites.

[0093] In the FIG. 6, U, G, E, T and BT composites were bonded to human dentin without any dentin adhesive. C and S were bonded to human dentin using the recommended total etch and se ^' lf-etch techniques- based dentin adhesives. GIC is the self-adhesive dental restorative cement available in the market which does not use any adhesive to bond to. human dentin. From the FIG. 6 it is evident that the experimenta l composites U, G, E and T are bonded to human dentin without any adhesive.

Example 6

[0094] Objective: To study the rate of dimensional change in the conventional composite and the experimental composite.

[0095] Comparison tests were conducted to check the rate of expansion and shrinkage in the conventional composite and the experimental composite.

[0096] FIG. 7 represents the rate of dimensional change in the experimental dental composites and the conventional composites.

[0097] In the FIG. 7, x-axis indicates dimensional change in percentage and y- axis indicates time taken for the change.

[0098] In the FIG. 7, the experimental dental composites U and T showed no shrinkage at all the time intervals tested. A mild expansion, having not more than 1.2% was noted for U and T, which is within the standard recommended by ADA for dental materials. Further, the experimental composites G and E showed mild shrinkage till 1 h which was less than commercial composites R and C and initially not different from the low-shrink commercial composite S.

Example 7

[0099] Objective; To study the oxygen inhibition in the conventional composite and the experimental composite.

[00100] Comparison tests were conducted to check the oxygen inhibition in the conventional composite and the experimental composite.

[00101] In the FIG. 8A to 8H, x-axis indicates wave number in cm-1 and y- axis indicate absorbance. In the FIG. 8A, shows the lack of oxygen inhibition in the novel organic matrix containing the experimental composite 1 U (C=C peak area 0.013) at 2mm thickness when compared with the internal standard control composite 5BT (C=C peak area 0.014) at 2mm.

[00102] Further, the FIG. 8B shows the lack of oxygen inhibition in the novel organic matrix containing the experimental composite 1 U (C=C peak area 0.004) at 4mm thickness when compared with the control commercial composite 8C (C=C peak area 0.01) at 4mm.

[00103] Similarly, the FIG. 8C shows the lack of oxygen inhibition in the novel organic matrix containing the experimental composite 1 U (C=C peak area 0.004) at 4mm thickness when compared with the internal standard control composite 5BT (C=C peak area 0.01 ) at 4mm.

[00104] The FIG. 8D shows the lack of oxygen inhibition in the novel organic matrix containing the experimental composite 2G (C=C peak area 0.002) at 2mm thickness when compared with the control commercial composite 7R (C=C peak area 0.006) at 2mm.

[00105] Further, the FIG. 8E shows the lack of oxygen inhibition in the novel organic matrix containing the experimental composite 2G (C=C peak area 0.002) at 2mm thickness when compared with the control commercial composite 8C (C=C peak area 0.005) at 2mm.

[00106] Furthermore, the FIG. 8F shows the lack of oxygen inhibition in the ^: novel organic matrix containing the experimental composite 3E (C=C peak area 0.001) at 2mm thickness when compared with the control commercial composite 8C (C=C peak area 0.005) at 2mm.

[00107] Similarly, the FIG. 8G shows the lack of oxygen inhibition in the novel organic matrix containing the experimental composite 3E (C=C peak area 0.008) at 2mm thickness when compared with the internal standard control composite 5BT (C=C peak area 0.014) at 2mm.

[00108] The FIG. 8H shows the lack of oxygen inhibition in the novel organic matrix containing the experimental composite 3E (C=C peak area 0.001) at 2mm thickness when compared with the control commercial composite 7R (C=C peak area 0.006) at 2mm. [00109] Dental composites available currently are prone to inhibition of polymerization reaction in the presence of oxygen. Unless special precautions are taken like covering the surface of polymerizing material with light-transmitting films, this cannot be prevented. However during the experiment, the experimental dental composites 1U, 2G 3E and 4T were found to undergo un- inhibited polymerization in the presence of oxygen as evidenced by the significant reduction in peak areas under their respective polymerizing groups. In the above the FIGS 8A to 8H the area under peak indicates that the oxygen inhibition is not there.

[00110] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.