ONE STEP GINGIVA RETRACTION AND IMPRESSION MATERIAL AND METHOD

Abstract

A dental retraction and impression system providing self-retracting and impression taking of a prepared tooth in one step. Paired setting materials simultaneously retract gingiva, widen a sulcus around the tooth, and take an impression of the tooth and margins. A low viscosity setting gingival retracting impression material having an astringent and a high viscosity setting impression material set together. The high viscosity setting impression material is heavy body and has a higher viscosity than the low viscosity setting gingival retracting material so as to force the low viscosity setting gingival retracting impression material into the gingival space or sulcus.

Claims

1. Paired setting dental gingival retraction impression materials comprising: a setting low viscosity dental impression material; a retracting agent mixed within said setting low viscosity dental impression material; a setting high viscosity dental impression material, wherein said setting low viscosity dental impression material is configured to have a harder onset earlier than said setting low viscosity dental impression material.

2. Paired setting dental gingival retraction impression materials as in claim 1 wherein: said setting low viscosity dental impression material has a viscosity ranging from 120,000 to 150,000 cP; and said setting high viscosity dental impression material has a viscosity greater than 150,000 cP.

3. Paired setting dental gingival retraction impression materials as in claim 1 wherein: said setting high viscosity dental impression material has a viscosity greater than 400,000 cP.

4. Paired setting dental gingival retraction impression materials as in claim 1 wherein: said retracting agent is selected from the group consisting of aluminum chloride, aluminum potassium sulfate, aluminum sulfate, alum, or ferric sulfate.

5. Paired setting dental gingival retraction impression materials as in claim 1 wherein: said retracting agent comprises aluminum sulfate.

6. Paired setting dental gingival retraction impression materials as in claim 5 wherein: said aluminum sulfate comprises greater than ten percent by weight of said setting low viscosity dental impression material.

7. Paired setting dental gingival retraction impression materials as in claim 1 wherein: said setting high viscosity dental impression material has a consistency sufficient to force said setting low viscosity gingival retracting impression material into a sulcus around the prepared tooth.

8. Paired setting dental gingival retraction impression materials as in claim 1 wherein: said setting high viscosity setting impression material has a first hardness when set greater than a second hardness of said setting low viscosity gingival retracting impression material when set.

9. Paired setting dental gingival retraction impression materials as in claim 8 wherein: the first hardness of the setting high viscosity impression material when set is greater than eighty on a Shore hardness type A scale.

10. A kit for providing material for retracting gingiva around a prepared tooth and forming an impression of the prepared tooth in a single operation comprising: a low viscosity setting gingival retraction impression material having a first viscosity; and a high viscosity setting impression material having a second viscosity, wherein the second viscosity is higher than the first viscosity; and wherein said high viscosity setting impression material is configured to have a harder onset earlier than said low viscosity setting gingival retraction impression material, whereby said low viscosity setting gingival retraction impression material is capable of being placed around the prepared tooth and said high viscosity setting impression material is capable of being placed over said low viscosity setting gingival retracting impression material and permitted to set so that gingiva surrounding the prepared tooth is retracted simultaneously with forming the impression of the prepared tooth.

11. A kit for providing material for retracting gingiva around a prepared tooth and forming an impression of the prepared tooth as in claim 10 wherein: the first viscosity ranges from 120,000 to 150,000 cP.

12. A kit for providing material for retracting gingiva around a prepared tooth and forming an impression of the prepared tooth as in claim 10 wherein: the second viscosity is greater than 400,000 cP.

13. A kit for providing material for retracting gingiva around a prepared tooth and forming an impression of the prepared tooth as in claim 10 further comprising: a retracting agent selected from the group consisting of aluminum chloride, aluminum potassium sulfate, aluminum sulfate, alum, or ferric sulfate mixed with said low viscosity setting gingival retraction impression material.

14. A kit for providing material for retracting gingiva around a prepared tooth and forming an impression of the prepared tooth as in claim 10 further comprising: a tip having mixing portion and a cannula; and a dental tray.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 schematically illustrates the present invention and application of a low viscosity setting gingival retracting impression material.

[0017] FIG. 2 schematically illustrates the present invention and application of a high viscosity setting impression material.

[0018] FIG. 3 schematically illustrates the placement of a high viscosity setting impression material in a dental tray.

[0019] FIG. 4 illustrates a full dental tray.

[0020] FIG. 5 schematically illustrates the placement of a dental tray over a prepared tooth.

DETAILED DESCRIPTION OF THE INVENTION

[0021] FIGS. 1 and 2 illustrate the present invention. In FIG. 1 a prepared tooth 10 is surrounded by gingiva 14. A space or sulcus is formed between or at the margin of the gingiva 14 and the surface of the paired tooth 10. A syringe tip 16, attached to a syringe, not illustrated, has a cannula 18 thereon. The cannula 18 may be made of a malleable metal to facilitate placement and positioning. The cannula 18 may have a relatively small gauge to facilitate accurate placement of a low viscosity setting gingival retraction impression material 20 around the perimeter, and preferably around the entire exposed surface of the prepared tooth 10. The syringe tip 16 preferably has a mixing portion that has an augur for mixing two component materials. The low viscosity setting gingival retraction impression material 20 is extruded by the syringe through the syringe tip 16 and the cannula 18. The material 20 has a relatively low viscosity and contains a retracting agent, such as an astringent or hemostatic agent such as aluminum chloride, aluminum potassium sulfate, aluminum sulfate, alum, ferric sulfate or any other known retracting agent.

[0022] FIG. 2 illustrates the placement of a high viscosity setting impression material 22 around the perimeter of the prepared tooth 10 on top of the low viscosity setting gingival retraction impression material 20, illustrated in FIG. 1. The high viscosity setting impression material 22 may be placed on top of the low viscosity setting gingival retraction impression material 20 with a syringe, or preferably with a dental tray filled with the high viscosity setting impression material 22. The material 22 has a higher viscosity than the material 20. Additionally material 22 may, but generally need not contain a retracting agent.

[0023] The low viscosity setting gingival retracting impression material 20 has a setting time that is synchronized with the high viscosity setting impression material 22 so that the two materials 20 and 22 will set together forming a single unitary mold. Upon removal of the single unitary mold the impression of the prepared tooth 10 and the gingiva 14, including the sulcus 12 is formed. This impression may then be used as a mold in preparing a crown, bridge, inlay or overly to cover the prepared tooth.

[0024] The low viscosity setting gingival retracting impression material 20 preferably has a viscosity so that it can easily flow into the sulcus 12 around the prepared tooth 10 so as to form an accurate impression. The low viscosity setting gingival retracting impression material 20 also contains a retracting agent so that the gingiva 14 is retracted from the surface of the prepared tooth 10 so as to make possible the taking of a more detailed impression of the prepared tooth 10 so as to provide a good quality impression. The high viscosity setting impression material 22 has a higher viscosity than the low viscosity setting gingival retracting impression material so as to provide a heavier backing material to gently force the low viscosity setting gingival retracting impression material 20 into the sulcus 12. The higher viscosity setting impression material 22 is heavy body and has a mousse-like consistency. The higher viscosity setting impression material 22 has a stiffness sufficient to force or drive the low viscosity setting gingival retracting impression material into the sulcus 12 around the prepared tooth 10. The high viscosity setting impression material 22 preferably has a hardness when set greater than the low viscosity setting gingival retracting impression material 20 when set. The high viscosity setting impression material 22 may have a Shore hardness type A scale greater than eighty when set. Shore hardness is measured with a durometer. This aids in retraction and providing a good impression. This also prevents injury to the gingiva by providing a compliant yet firm force. The heavier setting or high viscosity setting impression material 22 also provides additional strength when combined or attached to the low viscosity setting gingival retracting impression material 20 while also facilitating the removal of the combined single unitary mold from the prepared tooth 10 and the gingiva 14 without breaking or separating so as to provide an accurate impression. A syringe or a dental impression tray may be used to apply the high viscosity setting impression material 22 to the prepared tooth 10 and the low viscosity setting gingival retracting impression material 20.

[0025] Both impression materials 20 and 22 are preferably based on a vinylpolysiloxane or VPS impression material. The VPS impression material has a combination of physical properties that provide strength, elasticity, dimensional stability, and the ability to register detail in any environment. The VPS impression material can provide a wide selection of viscosities and set times. The VPS material has two components that when mixed set into a flexible solid.

[0026] Preferably, the low viscosity setting gingival retracting impression material is thinned to a consistency of a wash type material having a viscosity of 120,000 to 150,000 cP or centipoise at room temperature. For example, water has a viscosity of 0.899 cP at 25° C. This low viscosity setting gingival retracting impression material 20 is placed by the tip 16 and syringe, not shown, around the sulcus and over the tooth to provide retraction as well as fine detail required for an accurate impression. The high viscosity setting impression material 22 is a heavy body, higher viscosity matrix having a viscosity preferably greater than 400,000 cP, or backing material and that adheres to an impression tray and the low viscosity setting gingival retracting impression material, facilitating simultaneous removal of both materials 20 and 22. The high viscosity setting impression material 22 has sufficient body or viscosity to force and hold the low viscosity setting gingival retracting impression material 20 in and around the sulcus 12 or margin between the gingiva 14 and the prepared tooth 10. Both materials 20 and 22 have setting times that are synchronized so that both materials set at approximately the same time so that they adhere together. If desired, the low viscosity setting gingival retracting impression material 20 may be adjusted to have a slightly longer set time substantially equal to a time required to apply the high viscosity setting impression material 22 over the low viscosity setting gingival retracting impression material 20, so that both materials 20 and 22 set together either simultaneously or at approximately the same time.

[0027] An additional advantage of adjusting the set time of the low viscosity setting gingival retracting impression material 20 longer than the high viscosity setting impression material 22 is that as the high viscosity setting impression material 22 sets it gets stiffer or harder earlier than the low viscosity setting gingival retracting impression material 20 creating more of a backing for driving the low viscosity setting gingival retracting material 22 into the sulcus 12. This aids retraction and improves the resulting impression.

[0028] The low viscosity setting gingival retraction impression material 20 is preferably applied around the sulcus 12 or margin between the prepared tooth 10 and the gingiva 14 with a syringe and syringe tip 16. The low viscosity setting gingival retraction impression material 20 is preferably placed over the entire exposed prepared tooth 10 surface. The high viscosity setting impression material 22 may be similarly applied with a syringe as illustrated in FIG. 2, but is preferably applied by first placing it in a dental impression tray, as illustrated in FIG. 3-5, and applied over the prepared tooth 10 and the low viscosity setting gingival retracting impression material 20 so as to form the impression. Therefore, after both materials 20 and 22 set and upon removal of the dental impression tray 24 or 30 both materials 20 and 22 are set and remain attached together as well as attached to the dental impression tray 24 or 28 so as to be removed in a single unit. This single unit or single unitary impression may then be used by a dental lab to prepare a crown, bridge, inlay, or overlay to fit over the prepared tooth 10.

[0029] FIGS. 3-5 illustrate a preferred technique or method for applying the high viscosity setting impression material. FIG. 3 illustrates the placement of the high viscosity setting impression material 22 into a quadrant or partial dental tray 24 or a full dental tray 28 having a groove or channel 30. The partial or full dental tray 24 and 28 maybe made of a porous flexible material or a non-porous rigid plastic material. The dental trays 24 or 28 need only be sufficiently rigid to prevent undue flexing so as to result in an accurate impression. The high viscosity setting impression material 22 may be placed in the dental trays 24 or 28 with a bulk syringe 26 having a nozzle. FIG. 4 illustrates a full dental tray which may also be used if a full dental impression is desired. A tray having different sizes for of any desired section or quadrant of the mouth may be used.

[0030] FIG. 5 schematically illustrates the low viscosity setting gingival retracting impression material 20, the high viscosity setting impression material 22, and a partial dental tray 24 applied to a prepared tooth 10. The low viscosity setting gingival retracting impression material 20 is placed into the sulcus 12 between the gingiva 14 and around and over the prepared tooth 10, preferably as illustrated in FIG. 1. The partial dental tray 24 is filled with the high viscosity setting impression material 22 and is positioned over the prepared tooth 10 so that the high viscosity setting impression material 22 is in contact with and covers the unset low viscosity setting gingival retracting impression material 20. Optionally, some of the high viscosity setting impression material 22 may be placed on the top of the prepared tooth 10 prior to placement of the filed cap or partial dental tray 24. Adjacent opposing tooth 32 may be used by the patient to apply pressure to the cap or partial dental tray 24.

[0031] The present invention is a unique dental impression system that makes taking a dental impression easier and more predictable. The low viscosity setting gingival retracting impression material stops fluid flow and controls bleeding and gently displaces the soft tissue or gingiva around the prepared tooth. The low viscosity setting gingival retracting impression material may contain more than 10%, and preferably 15% by weight of a retracting agent, such as aluminum sulfate. The retracting agent in combination with the low viscosity setting gingival retracting impression material and pressure applied by the high viscosity setting impression material retracts the gingiva widening the sulcus adjacent the prepared tooth creating a space permitting the low viscosity setting gingival retracting impression material to flow therein. This facilitates capturing all the margins resulting in a clear final impression.

[0032] The present invention is a gingiva retraction and impression system comprising use in combination of a low viscosity setting gingival retracting impression material and a high viscosity setting impression material. The system also comprises mixing nozzles and delivery tips used in a syringe, preferably having a mechanical advantage. The low viscosity setting gingival retracting impression material typically comprises two components that are mixed with a mixing nozzle and extruded through a delivery tip for placement around the prepared tooth. The high viscosity setting impression material also typically comprises two components that are mixed together with a mixing nozzle and extruded through a delivery tip. After mixing the two impression martials set. The system also comprises a dental tray in which the high viscosity setting impression material is placed before placement on the prepared tooth. The two impression materials work together in a single step to retract the gingiva and form an impression of the prepared tooth and margins. The impression is then used in making a crown, bridge, inlay, overlay or other dental work.

[0033] The single step gingival retraction and impression system of the present invention may be practiced according the following steps. Prepare the tooth for taking an impression and dry the area, place the low viscosity setting gingival retracting impression material into the gingival sulcus and around the tooth with a syringe, place the high viscosity setting impression material in a tray, placed the tray with the high viscosity setting impression material over the unset low viscosity setting gingival retracting impression material, apply pressure until the two impression materials are set, typically between 3 and 5 minutes, remove the tray together with the set two impression materials.

[0034] The present invention permits a clinician to take an accurate impression without the need for a prior retraction step. By combining the retraction necessary in a single step with taking an impression, the present invention saves time and cost, as well as makes dentistry easier.