MULTIPLE VISCOSITY GUTTA-PERCHA COATED ENDODONTIC INSTRUMENTS

Abstract

Disclosed herein is an obturator and methods of manufacturing an obturator for filling an endodontically prepared root canal. The obturator comprises an elongated carrier having a distal end, proximal end, and working portion with a combination of filler materials having multiple viscosities coated on the working portion.

Claims

1. An obturator for filling an endodontically prepared root canals, comprising: an elongated carrier having a distal end and a proximal end; a working portion extending from the distal end towards the proximal end; the working portion having an apical portion, a coronal portion end and an intermediate point; a coating of filler material surrounding the working portion of the elongated carrier; wherein the coating of filler material being arranged into at least three segments about the working portion; wherein the at least three segments include a first segment of first filler material characterized by a first viscosity, a second segment of second filler material characterized by a second viscosity and a third segment of third filler material characterized by a third viscosity.

2. The obturator according to claim 1, wherein the first filler material characterized by the first viscosity has a target melt flow of between 0 and 20 g/10 min.

3. The obturator according to claim 1, wherein the second filler material characterized by the second viscosity has a target melt flow of between 50 and 200 g/10 min.

4. The obturator according to claim 1, wherein the third filler material characterized by the third viscosity has a target melt flow of between 0 and 20 g/10 min.

5. The obturator according to claim 1, wherein the first segment extends from the distal end of the carrier to a first point of the apical portion; the second segment extends from the first point of the apical portion to the intermediate point of the working portion and the third segment extends from the intermediate point towards the coronal portion end of the working portion.

6. The obturator according to claim 5, wherein a length of the first segment is between 0.5 mm to 2 mm, a length of the second segment is between 5 mm to 10 mm, and a length of the third segment is between 5 mm to 10 mm.

7. The obturator according to claim 1, wherein the first segment extends from the distal end to the intermediate point, the second segment surrounds the first segment, the second segment extending from the distal end to the intermediate point, and the third segment extends from the intermediate point towards the coronal portion end of the working portion.

8. The obturator according to claim 7, wherein a length of each of the first segment and the second segment is between 5 mm to 10 mm from the distal end, and a length of third segment is between 5 mm to 10 mm.

9. The obturator according to claim 1, wherein the second segment extends from the distal end of the carrier towards coronal portion end, the first segment surrounds a portion of the second segment, the first segment extending from the intermediate point towards the coronal portion end of the working portion, and the third segment surrounds a portion of the second segment, the third segment extending from the distal end up to the intermediate point.

10. The obturator according to claim 9, wherein a length of the second segment is about 16 mm from the distal end to the coronal portion end, a length of the first segment is between 5 mm to 10 mm, and a length of the third segment is between 5 mm to 10 mm.

11. A method of manufacturing an obturator for filling an endodontically prepared root canal, the obturator comprising an elongated carrier having a distal end, a proximal end, and a working portion with a combination of filler materials having multiple viscosities coated on the working portion; said method comprising: (a) providing a mold having a plurality of cavities in the mold; (b) placing the at least two filler materials into each of the plurality of cavities of the mold; (c) baking the mold at a temperature of between 98.9° C. and 154.4° C. for from about 4 h to about 24 h to form the mold having a heated filler material comprising the at least two filler materials, whereby the at least two filler materials have different viscosities upon heating; (d) inserting the working portion of the carrier into the mold having the heated filler material; (e) placing a lid on top of the mold to keep the carrier at a correct depth; (g) allowing the heated filler material to cool at about room temperature, solidify and thereby forming a coating comprising the combination filler material having multiple viscosities on the working portion of the carrier, thereby forming obturator; and (h) removing the obturator from the mold.

12. The method according to claim 11, wherein the at least two filler materials are placed into each cavity of the mold in a following sequence: a first segment of a first filler material is placed into each cavity of the mold; subsequently a second segment of a second filler material is placed over the first segment of the first filler material into the same cavity of the mold, and finally then a third segment of a third filler material is placed over the second segment of the second filler material into the same cavity of the mold.

13. The method according to claim 11, wherein the at least two filler materials are provided in a form of an injected gutta-percha point.

14. The method according to claim 13, wherein the injected gutta-percha point is prepared by a gated-injection mold process.

15. A method of manufacturing an obturator for filling an endodontically prepared root canal, the obturator comprising an elongated carrier having a distal end, a proximal end, and a working portion with a combination filler material having multiple viscosities coated on the working portion; said method comprising: (a) forming an initial coating of a first filler material over the working portion of the carrier; (b) filling a mold having a plurality of cavities in the mold with a second filler material; (c) baking the mold to form the mold having a heated second filler material; (d) inserting the initial coated working portion carrier into each cavity of the mold having the heated second filler material; (e) placing a lid on top of the second mold to maintain the elongated carrier at a correct depth; (f) cooling the second filler material to form a subsequent coating of the second filler material on a portion of the initial coated working portion carrier, thereby forming the obturator and removing the obturator from the mold.

16. The method according to claim 15, wherein step (a) comprises: (i) inserting the working portion of the carrier into a container having a heated first filler material; (ii) optionally placing a lid on top of the container to keep the carrier at a correct initial depth; (iii) cooling the first filler material to form the initial coating of the first filler material over working portion of the carrier.

17. The method according to claim 16, wherein the container is selected from a crucible or a another mold having a plurality of cavities.

18. The method according to claim 16, wherein the container having the heated first filler material is obtained by baking the container filled with the first filler material at a temperature of between 98.9° C. and 154.4° C. for from about 15 min to about 4 h.

19. The method according to claim 15, wherein the mold having the second filler material is heated to a temperature of between 98.9° C. and 154.4° C. for from about 4 h to about 24 h.

20. The method according to claim 15, wherein the working portion has a taper, and the taper may be a constant taper or a variable taper along its length.

21. The method according to claim 16, wherein the correct initial depth is about 16 mm from the distal end of the carrier.

22. The method according to claim 15, wherein the heated first filler material is characterized by a first viscosity or a second viscosity.

23. The method according to claim 22, wherein when the heated first filler material is characterized by the first viscosity and is initially coated from a coronal end of the carrier to the distal end, the mold is filled with the second filler material up to between 5 mm and 10 mm from the distal end.

24. The method according to claim 15, wherein the heated second filler material is characterized by a second viscosity having a target melt flow between 50 and 200 g/10 min.

25. The method according to claim 22, wherein when the heated first filler material is characterized with the second viscosity and is initially coated from the distal end to a coronal end of the carrier; the mold is filled with second filler material to between 5 mm and 10 mm from the distal end, and is subsequently filled with a third filler material above the second filler material.

26. The method according to claim 15, wherein the initial coating thickness is from 10 μm to 500 μm over a length of the working portion.

27. The method according to claim 22, wherein the heated first filler material is characterized by the first viscosity having a target melt flow between 0 and 20 g/10 min.

28. The method according to claim 22, wherein the heated first filler material is characterized by the second viscosity having a target melt flow between 50 and 200 g/10 min.

29. The method according to claim 25, wherein the heated third filler material is characterized by the third viscosity having a target melt flow between 0 and 20 g/10 min.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0028] FIG. 1A depicts a side view of the silicone mold 21.

[0029] FIG. 1B depicts a side view of the silicone mold 22.

[0030] FIG. 2A depicts a top view of the silicone mold 22.

[0031] FIG. 2B depicts a silicone mold with a lid.

[0032] FIG. 3A demonstrates an obturator (40) of one embodiment with a multiple viscosity filling material coating.

[0033] FIG. 3B demonstrates an obturator (41) of another embodiment with a multiple viscosity filling material coating.

[0034] FIG. 3C depicts a three-segment obturator (42).

[0035] FIG. 4A demonstrates an obturator (43) of an embodiment with a multiple viscosity filling material coating.

[0036] FIG. 4B demonstrates an obturator (44) of another embodiment with a multiple viscosity filling material coating.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0037] The above-mentioned aspects, as well as other aspects, features, and advantages of the present disclosure are described below in connection with various embodiments, with reference made to the accompanying figures.

[0038] The endodontic instrument according the present disclosure is designed having a configuration of filler material disposed on the device that allows more filling material to flow apically, and laterally so it can fill in the canal anatomy properly. The endodontic instrument is an obturator for use in filling an endodontically prepared root canal.

[0039] The endodontic instrument includes an obturator for filling an endodontically prepared root canal, the obturator comprising: an elongated carrier having a distal end and proximal end; a working portion extending from the distal end towards the proximal end; the working portion having an apical portion, coronal portion and an intermediate point; a coating of filler material surrounding the working portion of the carrier; wherein the coating of the filler material is arranged into at least three segments about the working portion; wherein the at least three segments include a first segment of first filler material characterized by a first viscosity, a second segment of second filler material characterized by a second viscosity and a third segment of third filler material characterized by a third viscosity.

[0040] The endodontic instrument according to the present disclosure includes multiple viscosity filler material coatings. In one embodiment of the obturator, the first viscosity is different than second viscosity and the first viscosity is same as third viscosity.

[0041] The carrier may be made of a cross-linkable (e.g., thermoset) material (e.g., first rubber and/or plastic). Examples of cross-linkable materials include, but are not limited to, epoxides, phenolics (e.g., bakelite), polyimides, formaldehyde resins (e.g., urea formaldehyde or melamine formaldehyde), polyester thermosets, unsaturated polyesters, polyurethane, bis-maleimides (BMI), silicone, the like, or any combinations thereof. The cross-linkable material may be present in an amount of from about 1% to about 70%, such as from about 5% to about 45% (e.g., about 10% to about 25%) by wt of the carrier composition. Examples of a carrier composition are disclosed in U.S. Pat. No. 9,675,528, which is incorporated herein in its entirety by reference.

[0042] In an aspect of the obturator, a coating of filler material surrounds the working portion of the carrier. In one embodiment, the coating is a combination of filler materials having multiple viscosities.

[0043] The filler material may be any known filler material including, but not limited to, gutta-percha, thermoplastic, thermoset, chemoplastic, or other resin or polymeric material.

[0044] Examples of polymeric filler materials include, but are not limited to, polyacrylates/methacrylates, polyurethanes, polypropylenes, polyethylenes, polyamides, fluoropolymers, polyesters, polyphosphazenes, polyanhydrides, polysulfides, polyethers, epoxides, polycarbonates, polystyrenes, polyisoprenes, polybutadienes, polyphenylene oxides, silicone rubbers, polylactides, polyglycolides, polycaprolactones, polyamides, polyesteramides, polyorthoesters, polydioxanones, polyacetals, polyketals, polyorthocarbonates, polyhydroxybutyrates, polyhydroxyvalerates, polyalkylene oxalates, polyethylene oxides, polyalkylene succinates, poly(malic acid) polymers, polymaleic anhydrides, poly(methylvinyl) ethers, poly(amino acids), chitin, chitosan, polyamides, polyesters, polyolefins, polyimides, polyarylates, polyurethanes, vinyl esters or epoxy-based materials, styrenes, styrene acrylonitriles, ABS polymers, polysulfones, polyacetals, polycarbonates, polyphenylene sulfides, polyarylsulfides, acrylonitrile-butadiene-styrene copolymers, polyurethane dimethacrylates (hereinafter abbreviated to “UDMA”, triethylene glycol dimethacrylate (hereinafter abbreviated “TEGDMA”), polyethylene glycol dimethacrylate (hereinafter abbreviated “PEGDMA”), urethane dimethacrylate (hereinafter abbreviated “UDMA”), hexane diol dimethacrylate (hereinafter abbreviated “1,6 HDDMA”) and polycarbonate dimethacrylate (hereinafter abbreviated “PCDMA”) and copolymers, terpolymers, or combinations or mixtures thereof.

[0045] Examples of polyacrylates include, but are not limited to, polymethyl methacrylate, polyhydroxy ethyl methacrylate, or hydroxy ethyl methacrylate (HEMA). Examples of fluoropolymers include, but are not limited to, Teflon® PTFE or Teflon® PFA.

[0046] Examples of polyesters include, but are not limited to, polylactic acid, glycolide, polycaprolactone or a co-polymer thereof. An example of silicone rubber is polysiloxane.

[0047] The filler material according to the present disclosure are characterized by different viscosity upon heating.

[0048] The filler materials may be of the same formulation however made by different heat treatments to have different viscosities, For Example, baking the gutta-percha between 98.9° C. and 154.4° C. for between 4 hours and 24 hours to achieve the low viscosity gutta-percha, as disclosed in U.S. Pat. No. 5,372,759, which is incorporated herein by reference; or baking the gutta-percha between 98.9° F. and 154.4° C. for a period of time between 15 minutes and 4 hours to achieve the high viscosity gutta-percha.

[0049] The filler material may be of different formulations with different initial viscosities. For example the formulation for the low flow or high viscosity may be a matrix comprising a heat flowable material, wherein the heat flowable material is gutta-percha; and heat conductive particles of a size 1 micron or less dispersed in the heat flowable material of the matrix, wherein the particles are non-metallic, as disclosed in U.S. Pat. No. 9,192,545, which is incorporated herein in its entirety by reference.

[0050] The filler material for the low flow or high viscosity may include additional processing aid additives such as antioxidants, waxes, and/or saturated fatty acids.

[0051] For the obturators with three segments of filler material, the high viscosity filler material at the distal end of the obturator can provide an “apical plug” effect, which will help with stopping excess filler material from extruding through the apex of a root. In one embodiment of the obturator, filler materials are characterized by different viscosities upon heating. For example, a first filler material characterized by a first viscosity, a second filler material characterized by a second viscosity, a third filler material characterized by a third viscosity, and so on.

[0052] In one embodiment of the obturator, the first filler material is characterized by a first viscosity having a target melt flow between 0 and 20 g/10 min; alternatively, between 0.5 and 15 g/10 min; and alternatively, between 5 and 10 g/10 min.

[0053] In another embodiment of the obturator, the second filler material is characterized by a second viscosity having a target melt flow of above 50 g/10 min; alternatively, above 100 g/10 min or between 50 and 200 g/10 min or between 55 and 80 g/10 min.

[0054] According to yet another embodiment of the obturator, the third filler material is characterized by a third viscosity having a target melt flow of between 0 and 20 g/10 min; alternatively, between 0.5 and 15 g/10 min; alternatively, between 5 and 10 g/10 min.

[0055] The flow rates above are tested with a mass of 2.26 kg, a temperature of 108° C. and an orifice diameter of 0.0823 inches.

[0056] In one aspect of the obturator, the coating of filler material is arranged into at least three segments about the working portion. The at least three segments includes a first segment of first filler material characterized by first viscosity, a second segment of second filler material characterized by second viscosity and a third segment of third filler material characterized by third viscosity.

[0057] Each segment of the obturator may be arranged in a layer, for example, one or two layers of filler material (initial and subsequent) having different viscosities. There may be a variation that includes viscosity gradient in the filler material from the distal end to the coronal end of the filler material, or alternatively there is a viscosity gradient from the outside (subsequent layer) to the inside (initial layer) of the filler material.

[0058] An obturator with different filler material configurations coated about the working portion is illustrated in FIGS. 3A, 3B, 3C, 4A and 4B. An obturator ((40: as shown in FIG. 3A), (41: as shown in FIG. 3B), (42: as shown in FIG. 3C), (43: as shown in FIG. 4A), (44: as shown in FIG. 4B)), is depicted herein. The obturator comprises: an elongated carrier (31) having a distal end (32) and a proximal end (30); a working portion (33) extending from the distal end towards the proximal end. The distal end may have a diameter ranging from 0.2 mm to 2 mm. The working portion includes an apical portion (35), a coronal portion (34) and an intermediate point (33a). The coronal portion (34) ends at a coronal end (34a), while the apical portion (35) ends at the distal end (32) or tip end. The working portion (33) may be tapered or non-tapered. The taper may be a constant taper or a variable taper along the length of the working portion (33). The taper range may be from 0% to 10%. The length of the working portion is a length ranging from 14 mm to 20 mm.

[0059] In one embodiment of the obturator (42, FIG. 3C), the first segment (20a) extends from the distal end (32) of the carrier to a first point (35a) of the apical portion (35); the second segment (20b) extends from the first point (35a) of the apical portion to the intermediate point (33a) of the working portion and the third segment (20c) extends from the intermediate point (33a) towards the coronal end (34a) of the working portion. The length of the first segment is between 0.5 mm to 2 mm; alternatively, between 1 mm to 1.5 mm. The length of the second segment is between 5 mm to 10 mm, alternatively between 7 mm to 9 mm; and the length of the third segment is between 5 mm to 10 mm; alternatively, between 7 mm to 9 mm. The first segment (20a) includes a first filler material characterized by a first viscosity, the second segment (20b) includes a second filler material characterized by a second viscosity, and the third segment (20c) includes a third filler material characterized by a third viscosity.

[0060] In a more specific embodiment of the obturator (42, FIG. 3C), the first viscosity is different than the second viscosity and the first viscosity is the same as the third viscosity. The first segment (20a), the second segment (20b) and the third segment (20c) form a coating that surrounds the surface of the working portion from the coronal end to the distal end.

[0061] In another embodiment of the obturator (40, FIG. 3A), the first segment (10a) extends from the distal end (32) to the intermediate point (33a), the second segment (10b) surrounds the first segment (10a), the second segment extending from the distal end (32) to the intermediate point (33a), and the third segment (10c) extends from the intermediate point (33a) towards the coronal portion end (34a) of the working portion (33). The length of each of the first segment and the second segment is between 5 mm to 10 mm from the distal end; alternatively, between 7 mm to 9 mm. The length of the third segment is between 5 mm to 10 mm from the intermediate point to the coronal portion end. The first segment (10a) includes a first filler material characterized by a first viscosity, the second segment (10b) includes a second filler material characterized by a second viscosity, and the third segment (10c) includes a third filler material characterized by a third viscosity.

[0062] In a more specific embodiment of the obturator (40, FIG. 3A), the first viscosity is different than the second viscosity and the first viscosity is the same as the third viscosity. Alternatively, when the first viscosity is same as the third viscosity, the first segment (10a) and third segment (10c) form an initial coating that surrounds the surface of the working portion from the coronal end to the distal end, while the second segment (10b) coats the first segment (10a), extending from the distal end (32) to the intermediate point (33a). The total length of the first segment and the third segment is from about 16 mm to about 19 mm as measured from the distal end to the coronal end.

[0063] In yet another embodiment of obturator (41, FIG. 3B), the second segment (15a) extends up to from the distal end (32) of the carrier towards coronal end (34a), the first segment (15c) surround a portion of second segment (15a), extending from an intermediate point (33a) towards the coronal portion end (34a) of the working portion and the third segment (15b) surround a portion of second segment (15a), extending from the distal end (32) up to an intermediate point (33a). The length of the second segment (15a) is about 16 mm from the distal end (32) to the coronal end (34a); alternatively, about 19 mm. The length of first segment (15c) is between 5 mm to 10 mm as measured from the intermediate point (33a) towards the coronal portion end (34a) of the working portion (33); alternatively, between 7 mm to 8 mm. The length of the third segment (15b) is between 5 mm to 10 mm as measured from the distal end (32) to an intermediate point (33a); alternatively, between 7 mm to 9 mm. The first segment (15c) includes a first filler material characterized by a first viscosity, the second segment (15a) includes a second filler material characterized by a second viscosity, and the third segment (15b) includes a third filler material characterized by a third viscosity.

[0064] In a more specific embodiment of the obturator (41, FIG. 3B), the first viscosity is different than the second viscosity and the second viscosity is the same as the third viscosity. Alternatively, when the second viscosity is the same as the third viscosity, the portion of the second segment (15a) extending from the distal end (32) up to an intermediate point (33a) and the third segment (15b) overlap to form a coating that surrounds the surface of the working portion, while the first segment (15c) coats a portion of second segment (15a), extending from an intermediate point (33a) towards the coronal portion end (34a).

[0065] In a further embodiment of the obturator (43, FIG. 4A), a transition between the outer segments (50b) and (50c) is depicted. The first segment (50a) extends down from the coronal end (34a) of the carrier to the distal end (32), the second segment (50b) surrounds a portion of the first segment (10a), extending from the distal end up to an intermediate point (33a), and the third segment (50c) extending from intermediate point (33a) towards the coronal portion end (34a) of the working portion (33). The first segment (50a) includes a first filler material characterized by a first viscosity, the second segment (50b) includes a second filler material characterized by a second viscosity, and the third segment (50c) includes a third filler material characterized by a third viscosity. In a more specific embodiment, the first viscosity is different than the second viscosity and the first viscosity is the same as the third viscosity.

[0066] In yet a further embodiment of the obturator (44, FIG. 4B), a multiple viscosity filling material coating having several segments is shown. The first segment (60g) extends down from the coronal end (34a) of the carrier to the distal end (32). The second segment (60a) extends from the distal end (32) of the carrier to a first point (35a) of the apical portion (35); the third segment (60b) extends from the first point (35a) of the apical portion to the intermediate point (33a) of the working portion; the fourth segment (60c) extends from the intermediate point (33a) to the intermediate point (33b) of the working portion; the fifth segment (60d) extends from the intermediate point (33b) to the intermediate point (33c) of the working portion; the sixth segment (60e) extends from the intermediate point (33c) to the intermediate point (33d) of the working portion and the seventh segment (60f) extends from the intermediate point (33d) towards the coronal end (34a) of the working portion. The length of the first segment (60g) is about 16 mm from the 16 mm to about 19 mm as measured from the distal end to the coronal end. As one of ordinary skill in the art will understand, the number of segments over the first segment can be varied according to manufacturing process and can be as few as two overlaying segments, and as many as ten overlaying segments. The length of the second segment (60a) is between 0.5 mm to 2 mm; alternatively, between 1 mm to 1.5 mm. The length of the each of third segment (60b), fourth segment (60c), fifth segment (60d), sixth segment (60e) and the seventh segment (60f) is between 2 mm to 5 mm. The multiple segments of the obturator can be formed using different filler material characterized by different viscosities.

[0067] A method of manufacturing the obturators are herein disclosed. The method for manufacture of obturator 42 includes:

a) providing a mold having a plurality of cavities in the mold;
(b) placing the at least two filler materials into each of the plurality of cavities of the mold;
(c) baking the mold at a temperature of between 98.9° C. and 154.4° C. for from about 4 h to about 24 h to form the mold having a heated filler material comprising the at least two filler materials, whereby the at least two filler materials have different viscosities upon heating;
(d) inserting the working portion of the carrier into the mold having the heated filler material;
(e) placing a lid on top of the mold to keep the carrier at a correct depth;
(g) allowing the heated filler material to cool at about room temperature, solidify and thereby forming a coating comprising the combination filler material having multiple viscosities on the working portion of the carrier, thereby forming obturator; and
(h) removing the obturator from the mold.

[0068] The molds (11,12) to be used in the manufacture of the obturators according to the present disclosure are illustrated in FIG. 1A and FIG. 1B. The mold is preferably a silicone mold but can be made out of any suitable material that allows the formation and removal of the obturator from the mold. FIG. 2A depicts top view of the silicone mold 11 with a plurality of cavities (21) in the mold. FIG. 2B depicts silicone mold with a lid (22).

[0069] The at least two segments may include a first segment of a first filler material, a second segment of a second filler material, and a third segment of a third filler material.

[0070] In an embodiment of the method of manufacture of the obturator (42), the at least two filler materials are placed into each cavity the mold in a following sequence: a first segment (20a) of first filler material is placed into each cavity of the mold; subsequently a second segment (20b) of the second filler material is placed over the first segment of the first filler material into the same cavity of the mold, and finally then a third segment (20c) of the third filler material is placed over the second segment of the second filler material into the same cavity of the mold.

[0071] The length of the first segment is between 0.5 mm to 2 mm; alternatively, between 1.0 mm to 1.5 mm. The length of the second segment is between 5 mm to 10 mm, alternatively between 7 mm to 9 mm; and the length of the third segment is between 5 mm to 10 mm; alternatively, between 7 mm to 9 mm.

[0072] In one embodiment of the method, the at least two filler materials are provided in the form of an injected gutta-percha point. US. Pat. Appl. No 20140272802 and U.S. patent Ser. No. 10/484,633 disclose gutta-percha points made by injection molding; each reference is incorporated in its entirety herein by reference.

[0073] The gutta-percha point having the at least two filler materials is prepared by gated-injection mold process. For Example, a first filler material would be injected first while the other segments are gated off, then the second filler material would be injected. It is conceivable that either first filler material or second filler material could be injected first. The gates would be there for the first injection cycle, but then be removed for the second cycle so that it forms one filler material point with multiple segments. US. Pat. Appl. No. 20200094456 discloses gated injection molding of an obturator, which is incorporated herein in its entirety by reference.

[0074] The mold (12) containing at least two filler materials is baked in an oven to form the mold having heated filler material comprising the at least two filler materials, whereby the at least two filler materials have different viscosities upon heating. The mold is baked between 98.9° C. and 154.4° C. for about 4 h to about 24 h; Alternatively, the mold is baked between 110° C. and 143.3° C. for about 6 h to about 20 h; Alternatively, the mold is baked between 121.1° C. and 137.7° C. for about 8 h to about 16 h.

[0075] The at least two filler materials have different viscosities upon heating is intended to mean that after heating, the at least two filler materials includes a first segment of heated first filler material characterized by first viscosity, a second segment of heated second filler material characterized by second viscosity and a third segment of heated third filler material characterized by third viscosity. In a more specific embodiment, the first viscosity is different than the second viscosity and the first viscosity is the same as the third viscosity. For example, the heated first filler material is characterized by a first viscosity having a target melt flow between 0 and 20 g/10 min; alternatively, between 0.5 and 15 g/10 min; and alternatively, between 5 and 10 g/10 min. The heated second filler material is characterized by a second viscosity having a target melt flow of above 50 g/10 min; alternatively, above 100 g/10 min or between 50 and 200 g/10 min or between 55 and 80 g/10 min and the heated third filler material is characterized by a third viscosity having a target melt flow of between 0 and 20 g/10 min; alternatively, between 0.5 and 15 g/10 min; alternatively, between 5 and 10 g/10 min. In an embodiment, the first filler material and the third filler material may have same composition.

[0076] After the filler materials is heated; the working portion (33) of the carrier is inserted into each cavity of the mold having the heated filler material. A lid (22) is placed on top of the mold (12) to keep the carrier at a correct depth. The heated filler material will then be allowed to cool at room temperature for at least 1 hour; alternatively, between 2 to 4 h. The heated filler material then solidifies and forms a coating comprising the combination filler material having multiple viscosities on the working portion of the carrier, thereby forming obturator (42). The carrier/obturator is then removed from the mold.

[0077] Another aspect of a method of manufacturing the obturators is disclosed. The obturators 40, 41, 43 and 44 may be prepared by the method disclosed herein. The method includes:

(a) forming an initial coating of a first filler material over a working portion (33) of the carrier;
(b) filling a mold (12) having a plurality of cavities with a second filler material;
(c) baking the mold to form the mold having the heated second filler material;
(d) inserting the initial coated working portion carrier into each of the plurality of cavities of the mold having the heated second filler material;
(e) placing a lid (22) on top of the mold to maintain the elongated carrier at a correct depth;
(f) cooling the heated second filler material to form a subsequent coating of the second filler material on a portion of the initial coated working portion carrier, thereby forming the obturator and removing the obturator from the mold.

[0078] According to the present embodiment, the method of forming an initial coating of a first filler material over the surface of working portion (33) of the carrier includes (i) inserting the working portion of the carrier into a container having a heated first filler material; (ii) optionally placing a lid on top of the container to keep carrier at a correct initial depth; (iii) cooling the filler material to form an initial coating of a first filler material over a working portion of the carrier.

[0079] The container is selected from a crucible (1) or a initial mold (11) having a plurality of cavities (21). The container having a heated first filler material is obtained by baking the container filled with first filler material between 98.9° C. and 154.4° C. for about 15 min to about 4 h; Alternatively, the initial mold is baked between 121.1° C. and 137.7° C. for about 2 h to about 4 h. The mold having second filler material is heated between 98.9° C. and 154.4° C. for about 4 h to about 24 h; Alternatively, the mold is baked between 121.1° C. and 137.7° C. for about 8 h to about 16 h.

[0080] When the lid is placed on the top of the container to keep the carrier at a correct initial depth, the depth is about 16 mm from the distal end of the carrier.

[0081] The heated first filler material is characterized by a first viscosity or a second viscosity. The heated first filler material is characterized by first viscosity having a target melt flow of between 0 to 20 g/10 min; alternatively, between 0.5 and 15 g/10 min; and alternatively, between 5 and 10 g/10 min. The heated first filler material may be characterized by a second viscosity having a target melt flow of greater than 50 g/10 min; alternatively, above 100 g/10 min or between 50 and 200 g/10 min or between 55 and 80 g/10 min.

[0082] In an embodiment of the method of manufacture of obturator, when the heated first filler material characterized by a first viscosity is used to create an initial coating from the coronal end to the distal end working portion carrier (for example, first segment (10a) and third segment (10c) of obturator (40, FIG. 3A), wherein first viscosity is same as the third viscosity), then the mold (12) is filled with second filler material up to between 5-10 mm from the distal end (10b). The heated second filler material in step (c) of the method, is characterized by a second viscosity having a target melt flow of greater than 50 g/10 min; alternatively, above 100 g/10 min or between 50 and 200 g/10 min or between 55 and 80 g/10 min. After performing further subsequent step (c) to (f), the obturator 40 is obtained.

[0083] In yet another embodiment of the method, when the heated first filler material is characterized with a second viscosity is used to create an initial coating from the distal end to the coronal end of the carrier (for example, second segment (15a) of the obturator (41, FIG. 3B)); the silicone mold (12) is filled with a second filler material between 5-10 mm from the distal end (segment 15b) and subsequently filled with a third filler material (segment 15c) over the top of the second filler material. The heated second filler material in step (c) of the method, is characterized by a second viscosity having a target melt flow of greater than 50 g/10 min; alternatively, above 100 g/10 min or between 50 and 200 g/10 min or between 55 and 80 g/10 min. The heated third filler material is characterized by a third viscosity having a target melt flow of between 0 to 20 g/10 min; alternatively, between 0.5 and 15 g/10 min; and alternatively, between 5 and 10 g/10 min. After performing further subsequent step (c) to (f), the obturator 41 is obtained.

[0084] The initial coating thickness is from 10 μm to 500 μm over the length of the working portion.

[0085] While the present disclosure has been described with reference to one or more embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims. In addition, all numerical values identified in the detailed description shall be interpreted as though the precise and approximate values are both expressly identified.