Impression trays

Abstract

The impression tray for taking a dental impression of at least one tooth of the present invention comprises a base element having a base surface, a first boundary element and a second boundary element, the first boundary element and the second boundary element being arranged on the base element to form a receiving tray configured to receive a first dental impression material between the first boundary element, the base surface and the second boundary element, the base element having a cavity extending at least partially below the base surface, the cavity and the receiving tray being separated by a base layer of the base element, and the base element having an opening configured to be in fluid communication with the cavity to allow a second dental impression material to be injected into the cavity.

Description

[Technical field]

[0001] The present invention relates to an impression tray for taking a dental impression of at least one tooth, a method for taking a dental impression of at least one tooth using said impression tray, and a process for producing a corresponding dental prosthesis. The present specification also discloses a dental prosthesis, a use of the impression tray for taking a dental impression, and a kit for taking a dental impression. [Background technology]

[0002] In the creation of dental prostheses, also called dental restorations, it is often necessary to take an accurate impression of the patient's teeth for which the dental prosthesis is to be created. Typically, such an impression is taken using a dental impression tray, which has a receiving tray roughly shaped to the shape of the patient's upper or lower jaw and configured to hold a dental impression material. The filled impression tray is pressed against the patient's teeth to create an impression in the dental impression material, which, depending on the substance used, can be allowed to solidify around the teeth. The resulting negative copy of the teeth can then be used to cast models for dental restorations, such as crowns and bridges.

[0003] In the prior art, impression trays are typically of a relatively simple design having a base element that forms the bottom of a receiving tray surrounded on either side by boundary elements and configured to hold dental impression material therein.

[0004] The techniques used today differ mainly with regard to the application sequence of the dental impression material, in most cases different types of silicone rubber with different viscosities are used. The techniques known in the prior art differ in the accuracy with which they reproduce the details of the teeth, especially in the areas around the lower part of the teeth, especially below the gum level.

[0005] The most basic technique employs only a one-stage process that generally uses only a single dental impression material of medium viscosity. While this process is time- and cost-efficient, the reproduction of detail is often deemed insufficient, limiting the usefulness of this approach when a high level of detail is required. A modification of the one-stage process is a process in which two different types of dental impression materials are provided in the impression tray before it is placed in the patient's mouth. Thus, a relatively high viscosity dental impression material is provided in the impression tray as a base, and a second layer of a lower viscosity dental impression material is added. This setup enhances the quality of the impression by using the lower viscosity dental impression material to better penetrate small cavities around the teeth.

[0006] An improvement over the one-stage process that allows for a more accurate negative of the teeth to be obtained is the two-stage impression process, in which a first dental impression is taken using a first dental impression material of relatively high viscosity. After the first impression is taken and the tray is removed from the patient's mouth, a second dental impression material, generally of lower viscosity, is applied over the first impression before the impression tray is placed back into the patient's mouth. Although relatively time consuming, each process generally produces the best results in terms of impression detail, especially in areas below gum level. However, two-stage processes are often difficult to use on many teeth at the same time, because the time it takes to apply the second dental impression material can cause some of the low viscosity dental impression material to harden prematurely, reducing the quality of the impression taken.

[0007] All the above techniques are often considered to have further drawbacks. In particular, when a high quality impression of the portion of the tooth located below the gum level is required, prior art techniques most often require the use of gingival retraction cords that are placed around the teeth before the impression is taken in order to move and retract the gum tissue and to increase the clearance between the gums and the teeth through which the dental impression material can flow. The need for retraction cords is a significant drawback as the application of such retraction cords can be very time consuming and is most often considered to be uncomfortable for the patient.

[0008] In all the above techniques, the quality of the impression can be hindered by gas inclusions in the dental impression material, especially by fluids remaining in the area around the teeth. Most notably, bleeding of the gums during the taking of the impression can lead to defective results and lack of precision. However, such bleeding of the gums is often exacerbated by the application of retraction cords, which must be treated and stopped before the impression can be taken, further increasing the time consumption of the entire procedure.

[0009] A further drawback can occur in a two-stage process when the access of the low viscosity dental impression material to certain parts of the tooth is restricted by the first impression of high viscosity dental impression material, which is formed by the initial pressing, because the tooth is tightly packed into said first impression.

[0010] In all the above techniques, to obtain sufficient accuracy, the first and second dental impression materials usually need to be applied over the entire impression tray, leading to increased material consumption and possible material spillage, which is often uncomfortable for the patient. Summary of the Invention [Problem to be solved by the invention]

[0011] The main object of the present invention was to eliminate or at least reduce the above-mentioned disadvantages of the prior art.

[0012] In particular, it was an object of the present invention to provide an improved impression tray and corresponding method for taking dental impressions that allows for more time- and cost-efficient taking of dental impressions.

[0013] It was now an object of the present invention to provide an impression tray and a corresponding method which allow dental impressions to be taken with greater accuracy, even for details below the gum level.

[0014] It was a further object of the present invention to enable the impression tray and corresponding method to allow for the taking of highly accurate dental impressions without the need for gingival retraction cords, as well as to allow the use of said impression tray and corresponding method to address gas inclusions in dental impression materials as well as residual fluids around the teeth, in particular bleeding gums.

[0015] It was an object of the present invention to make it possible to design an impression tray that is easy to manufacture and allows for sustainable reuse of a large portion of said impression tray.

[0016] It was a further object of the invention to make it possible to carry out said method using only raw materials and tools available to the dentist or dental laboratory worker.

[0017] A further object of the present invention was to minimize the amount of formulation required prior to dental impression taking and to minimize waste generation in the process. Also, since the process of taking an accurate dental impression is often considered difficult even for trained professionals, it was an object of the present invention to provide a dental impression tray and corresponding method that requires less training to perform and that allows for highly accurate dental impressions to be taken with a reduced amount of training and experience required of the operator.

[0018] It was a further object of the present invention to conserve material and reduce patient exposure to dental impression materials by enabling the impression tray and corresponding method to accurately take individual tooth impressions.

[0019] The inventors of the present invention have been working to find a solution to the above problem for over 20 years. In early internal experiments, the inventors considered modifying existing impression trays by applying an elastic space holder to the bottom of the receiving tray. Therefore, an elastic space holder, e.g., a rubber cord, was placed on the bottom of the impression tray before applying the high viscosity dental impression material. The intention was that after taking the first dental impression, the elastic space holder would be removed from under the hardened dental impression material to obtain a hollow space under the first dental impression in the hardened dental impression material.

[0020] In each prototype, the elastic space holder was pulled out of the receiving tray through the opening in the outer wall. The first dental impression material was hardened and the elastic space holder was removed through the opening in the side wall, which accordingly fluidly connected with the hollow channel in the hardened first dental impression material. The idea was that for any target tooth, the first dental impression material was penetrated at the bottom of the tooth impression to establish a fluid connection between the hollow channel in the first dental impression material and the tooth impression. The thus-processed receiving tray was placed back into the patient's mouth. A second dental impression material was then pushed through the opening and the hollow channel towards the impression so as to conform (under pressure) to the shape of the tooth to be placed in the first impression.

[0021] Although the inventors considered the general concept promising, each method as a whole did not work well enough in internal experiments. In particular, the time required to fabricate dental impression trays with flexible space holders increased the overall time consumption of the process. In particular, the flexible space holders usually had to be fixed to the bottom of the impression tray by a piece of dental impression material, but the precise placement of each flexible space holder required extensive training of employed workers, further limiting the effectiveness of the initial solutions.

[0022] Also, the width of the flexible spacer holder is essentially limited so that the hollow channel in the first dental impression material is relatively small so as not to deteriorate the adhesive strength of the dental impression material in the dental impression tray. Therefore, in the inventor's own experiments, it was found that in many cases, it was difficult to accurately hit the small channel in the dental impression material when penetrating the first dental impression material, and the use of this technique required too much training. In addition, the usefulness of the earlier method was limited when specific details were required in the impression placed too far from the small hollow channel provided in the dental impression material. Also, the small hollow channel was susceptible to premature hardening of the second dental impression material in the channel.

[0023] Apart from the above steps, the initial solutions envisaged by the inventors also proved unfavourable during the application of the method. Firstly, due to the flexible nature of the space holder, deformation of the flexible space holder when pressure is applied by the patient's teeth may lead to said flexible space holder compressing and further reducing the diameter of said small hollow channel. In the inventors' experiments, this may result in difficulties in removing the flexible material from under the hardened dental impression material and may even prevent parts of the desired channel from being in contact with the second dental impression material. Overall, it was found that the removal of the flexible space holder is relatively difficult and there is always a risk of mechanically damaging the adhesive connection between the first impression and / or the first dental impression material and the impression tray during removal. Similarly, the inventors found unfavourable that the reusability of the removed elastic space holder was rather low and that the respective method further generated a large amount of plastic waste.

[0024] However, the main reason why the inventors redesigned their approach was based on the fact that the best impressions were obtained by applying the second dental material to the openings and channels with a pressure high enough to completely penetrate all the details of the tooth, including the area below the gum line, thereby removing any liquids or gaseous inclusions such as blood. However, in the inventors' own experiments, the earlier solution did not work well enough when the necessary pressure was applied. Most notably, this was because hollow channels were formed between the bottom of the tray and the first dental impression material. The application of pressure by the injection of the second dental material exerted delamination forces that could separate the first dental impression material from the underlying impression tray, and in some tests, the second dental impression material at least partially destroyed the connection between the first dental impression material and the tray. This resulted in undesirable leakage of material from the impression tray (e.g., between the frame of the impression tray and the first dental impression material) and undesirable release of the second dental impression material into the patient's mouth. The inventors have found that even if the pressure exerted by the injection of the second dental impression material does not distort the bond between the first dental impression material and the impression tray, it can cause undesirable deformation of the first impression, resulting in warping and distortion of the entire impression. [Means for solving the problem]

[0025] After continued development, the inventors have found that the above object can be surprisingly solved by means of a dental impression tray as defined in the claims. Herein, by providing the dental impression tray itself with a cavity with an opening, the need for an elastic space holder is eliminated and the above drawbacks are eliminated. With the dental impression tray of the present invention, the first dental impression material can be applied directly to the receiving tray without the need for further processing, making the taking of the first dental impression comparable to the known two-step process. After taking the first impression, the first dental impression material can be penetrated with a common drilling tool at any point relative to any desired tooth, and the bottom of the receiving tray can also be penetrated to establish a fluid connection between the cavity of the impression tray and the impression taken with the first dental impression material. After the impression tray thus processed is placed back in the patient's mouth, a second dental impression material is injected under pressure through the opening into the cavity and through the obtained through-hole into the first impression, adapting to the shape of the teeth with high local selectivity and high precision. Each process allows for the acquisition of high quality dental impressions in a short time, typically about 3-4 minutes, without the need for special training or experience, resulting in a significant increase in time efficiency compared to prior art methods that often require 20 minutes or more to acquire a dental impression with sufficient accuracy. The harmful effects of blood and other fluids as well as gaseous inclusions are suppressed by the application of pressure during injection, beneficially eliminating the need for retraction cords except in the most difficult cases. Compared to the inventor's previous conception, waste generation is reduced and the reliability as well as the time efficiency of the process are significantly improved. Most importantly, since the pressure applied by the injection of the second dental impression material does not affect the interface between the impression tray and the first dental impression material, the undesired release of the second dental impression material into the surroundings of the impression tray and delamination of the first impression material and the receiving tray can be completely prevented.

[0026] The above mentioned objects are achieved by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention are disclosed in the dependent claims and in the following description. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The embodiments which are preferred below are combined in particularly preferred embodiments with features of other preferred embodiments. Thus, combinations of two or more embodiments described below as particularly preferred are highly preferred. Also preferred are embodiments in which features of one embodiment which is preferred to a certain extent are combined with one or more additional features of other embodiments which are preferred to a certain extent. The features of the preferred methods, dental prostheses, uses and kits correspond to the features of the preferred impression trays.

[0028] The impression tray for taking a dental impression of at least one tooth according to the present invention comprises: a base element having a base surface; A first boundary element; a second boundary element; the first boundary element and the second boundary element are disposed on the base element to form a receiving tray configured to receive a first dental impression material between the first boundary element, the base surface, and the second boundary element; The base element has a cavity extending at least partially below the base surface, the cavity and the receiving tray being separated by a base layer of the base element, and the base element has an opening configured to be in fluid communication with the cavity and to allow a second dental impression material to be injected into the cavity.

[0029] The above-mentioned configuration of the base element, the first boundary element and the second boundary element corresponds to a common configuration of dental impression trays known to a person skilled in the art, where the base element is the bottom of the impression tray having a surface which is part of the receiving tray, in other words the part of the impression tray which is configured to receive the dental impression material and on which the dental impression material can be placed.

[0030] Unlike the prior art, the base element has a cavity that extends at least partially below the base surface. In other words, the base layer is the wall of the cavity facing the receiving tray, and its outer surface forms the base surface of the receiving tray. This cavity has an opening that allows the injection of the second dental impression material into the cavity. Thus, the impression tray of the present invention is adapted and configured for use in the method of the present invention, and a direct fluid communication between the cavity and the receiving tray can be established by penetrating the base layer of the base element, for example with a drill.

[0031] From the above description, it is clear that the receiving tray is suitable for receiving the first dental impression material and the opening is suitable for injecting the second dental impression material into the cavity. It is understood by those skilled in the art that the first dental impression material and the second dental impression material are not part of the impression tray of the present invention, but are provided in the method of the present invention for taking a final dental impression. The concept of the present invention can be applied to specific dental impression trays, such as impression trays that are exclusively focused around a specific part of the jaw or impression trays that can be used outside the human mouth, for example, to take an impression of a missing tooth or an impression of an animal, but a general design is recognized. The impression tray of the present invention that is typically used is most often configured to be placed in the human mouth so that at least one tooth is placed in the receiving tray, and / or the first and second boundary elements are configured to at least partially hold the first dental impression material in the receiving tray when replaced by at least one tooth, and / or the impression tray is configured to take a dental impression of multiple teeth, preferably all teeth of the upper or lower jaw, simultaneously.

[0032] An advantage of the present invention is that the impression tray of the present invention is very flexible in terms of the material. The impression tray is not limited in terms of the raw material used for its preparation, since the penetration of the base layer in the method of the present invention can be performed, for example, with a dental drill suitable for molding hard materials. Preferably, the impression tray of the present invention is such that the base element and / or the first boundary element and / or the second boundary element comprise a material selected from the group consisting of metal materials and plastic materials, preferably plastic materials, more preferably thermoplastic resins and thermosetting resins, said elements preferably consisting of the respective materials. It is clear that a person skilled in the art will in most cases not use materials that have known adverse health effects and are not considered safe for application in the human mouth.

[0033] The inventors of the present invention have found that using a rigid material is beneficial, but the skilled person can identify suitable rigid materials, such as plastics. The application of elastic materials may be interesting for certain applications, but the inventors have found that the use of elastic materials may cause pressure changes caused by the injection of the second dental material into the first dental material to be propagated, resulting in deformation or distortion of the bond at the interface between the first impression material and the impression tray. Preferably, the impression tray of the present invention is such that the base element and the base layer are made of a rigid material, preferably a metal material, a ceramic material or a rigid plastic material.

[0034] Among the above mentioned materials, plastic materials are preferred, since they not only facilitate the penetration of the base layer, but are also relatively cheap and can be produced in a very efficient manner, for example by injection molding. It is also possible to produce the base element and the base layer from metal materials, for example aluminum or titanium, but in many cases the penetration of these materials is considered to be too difficult and the price unfavorable.

[0035] In some applications it is beneficial if the base element consists of a single piece. This allows for efficient production of the components, for example by injection moulding of plastic. The respective impression trays are usually not reusable. However, this is often not considered a drawback, since for hygiene reasons different impression trays are often used for different patients. Therefore, preferably, the impression tray of the present invention has a base element consisting of a single piece.

[0036] However, for some applications, it may be advantageous to use a base element consisting of two or more parts. This is beneficial, for example, for storing parts, for example, an impression tray is assembled from two or more parts just before the process. Among designs with two or more parts, a particularly beneficial embodiment is a base element, in which the base layer is replaceable and the impression tray is at least partially configured to be reusable. In this embodiment, the body of the base element may be made, for example, from a metal material, and the cavity may be formed between the base layer and the main part of the base element, for example, by inserting a plastic base layer into the remaining part of the base element. When the base layer is pierced with the method of the invention, the replaceable base layer can be easily removed together with the hardened dental impression material, while the body of the base element is usually reused together with the first and second boundary elements. In this embodiment, waste generation may be minimized. Accordingly, preferably, the impression tray of the present invention is configured such that the base element consists of two or more parts connected to each other, and the cavity is preferably formed between a first part having the base layer and a second part having the opening, and / or the base element consists of two or more parts, and the base layer of the base element is configured such that it is reversibly and non-destructively removable from the other parts of the base element, and the base layer preferably consists of a replaceable part and the other parts of the base element preferably consist of reusable parts.

[0037] In order to enhance the adhesion between the base surface and the first dental impression material, the inventors propose that the base surface should be configured, for example, to have a plurality of macroscopic protrusions thereon. Thus, preferably, the impression tray of the present invention is such that the base surface is a textured surface, the base surface preferably has a plurality of macroscopic protrusions and / or is substantially uniformly configured over the entire surface area.

[0038] The inventors of the present invention have been able to provide suitable design suggestions for the first boundary element and the second boundary element. That is, preferably, in the impression tray of the present invention, the first boundary element is a boundary wall, the shape of the boundary wall preferably corresponds to the shape of the front surface of the human dentition, and / or the first boundary element has one or more holes, preferably a plurality of holes, and the first boundary element more preferably has a lattice structure. Similarly, preferably, in the impression tray of the present invention, the maximum height of the first boundary element relative to the base surface is in the range of 10 to 38 mm, preferably in the range of 13 to 28 mm, more preferably in the range of 18 to 25 mm. Similarly, preferably, in the impression tray of the present invention, the second boundary element is a bulge, the shape of the bulge preferably corresponds to the shape of the human palate, or the second boundary element is a boundary wall, the shape of the boundary wall preferably corresponds to the shape of the back surface of the human dentition, and / or the second boundary element has one or more holes, preferably a plurality of holes. Additionally, preferably, in the impression tray of the present invention, the maximum height of the second boundary element relative to the base surface is in the range of 2 to 30 mm, preferably in the range of 5 to 20 mm, more preferably in the range of 10 to 17 mm.

[0039] In most applications, it is particularly preferred that the cavity essentially completely occupies the space below the base surface. In this embodiment, the bottom of the receiving tray, i.e. the base surface, always has a portion of the cavity directly below it. This embodiment is particularly beneficial as it allows high flexibility in penetrating the base layer and is very easy to establish fluid communication with the cavity without having to hit small structures below the base layer. Preferably, the impression tray of the present invention has the cavity extending essentially entirely below the base surface, and the projected areas of the base surface and the cavity are essentially the same, preferably in top view.

[0040] On the other hand, it may be preferable to limit the extent of the cavity below the base surface. Although it is generally recommended to have the cavity extend over its entire length, for example along the entire U-shape of a typical impression tray, it may be preferable to limit the width of the cavity below the base surface. This allows for more flexibility in making the impression tray and provides more stability overall. In particular, if the cavity is located in the center of the impression tray, the trade-off of being more difficult to hit during the piercing step of the method of the present invention is generally minor. In view of this, preferably, the impression tray of the present invention has a cavity that extends centrally below the base surface, preferably over the entire length of the base surface, and the width of the cavity is preferably in the range of 20-80%, preferably 30-70%, more preferably 40-60% of the width of the base surface.

[0041] Although it is possible to use relatively large cavities, the inventors suggest that the volume of the cavities should be kept small in order to reduce the amount of second dental impression material required to fill the cavities and to allow efficient application of pressure during injection.Accordingly, preferably the impression tray of the present invention has an average height of the cavities below the base surface in the range of 0.1-15 mm, preferably in the range of 0.5-5 mm, more preferably in the range of 1-2 mm.

[0042] With regard to efficiency of production and avoidance of undesired release of second dental impression material into the mouth, it is clearly beneficial to limit the number of openings in the cavity, although there may be more than one opening connected to the cavity.Preferably, the impression tray of the invention is such that the cavity has exactly one opening and / or the cavity is airtight except for the openings.

[0043] Considering the method of the present invention in the light of the above, it is clear to the skilled person that the opening is not located in the base layer of the base element, so that in the majority of cases the opening is not located in the base surface or is generally at least spatially separated from the part of the receiving tray that receives the first dental impression material. Thus, the opening does not establish a direct fluid connection between the receiving tray and the cavity. Thus, the skilled person will understand that the base layer usually does not have an opening configured to allow the second dental impression material to be injected into the cavity. Most preferably, the base layer and / or the base surface do not have any openings that are through holes. In other words, the impression tray of the present invention that is usually used is in most cases a base layer that is a hard base layer and / or that does not have a through hole that connects the receiving tray with the cavity.

[0044] The most convenient location of the opening can be identified based on the general constraints of the placement of the impression tray in the patient's mouth during dental impression taking. Typically, impression trays of the invention are used in most cases where the opening extends from the cavity through the base element to the outer surface of the impression tray and / or the opening is not located in the first or second boundary element.

[0045] To allow for easy injection of the second dental impression material, for example by a syringe, the inventors propose to arrange a tube in the opening, which can accommodate the injection part of the respective injection device during the process steps. The respective embodiment is particularly preferred, since it can further prevent undesired release of the second dental impression material from the syringe into the patient's mouth. Thus, preferably, the impression tray of the present invention is such that the opening connects with a tube, which is preferably configured to receive the injection element of an injection device, preferably a syringe, and / or the tube is preferably part of a handle, which facilitates handling of the impression tray, in particular its placement in and removal from the mouth.

[0046] Since the base layer needs to be penetrated in the method of the present invention, the inventors suggest that the thickness of the base layer should be fairly thin and may specify a preferred range that allows each impression tray to be easily prepared and reduces the risk of undesired penetration of the base layer. That is, preferably, the impression tray of the present invention has a base layer thickness in the range of 0.1 to 10 mm, preferably in the range of 1 to 3 mm, more preferably in the range of 1.5 to 2 mm.

[0047] The method of the present invention utilizing the impression tray of the present invention will now be described in more detail, which will be more readily understood by describing the exemplary process disclosed below with reference to the drawings. As disclosed above, the present invention relates to a method of taking a dental impression of at least one tooth using the impression tray of the present invention, (a) preparing an impression tray of the present invention; (b) filling a receiving tray with a first dental impression material to obtain a filled impression tray; (c) placing the filled impression tray into the person's mouth such that at least one tooth is located within the first dental impression material to obtain a temporary imprint of at least one tooth within the first dental impression material; (d) removing the impression tray with the temporary imprint from the mouth and penetrating the first dental impression material, preferably at the bottom of the temporary imprint together with the underlying base layer, with a drilling tool to form through holes and establish fluid communication between cavities and the temporary imprint to obtain a filled and remodeled impression tray; (e) placing the filled and remodeled impression tray back into the person's mouth such that at least one tooth is repositioned within the temporary imprint; (f) forcing a second dental impression material through the through hole and into the temporary imprint by injecting the second dental impression material through the opening and into the cavity, thereby conforming the second dental impression material to the shape of at least one tooth to form a final imprint; (g) removing the impression tray with the final imprint from the person's mouth. Steps (a)-(c) correspond to the general first step of the prior art two-step process described above. As explained above, the impression tray with the temporary imprint is then modified with a drilling tool to establish through holes through the first dental impression material as well as the base layer and to establish corresponding fluid communication between the cavities in the impression tray and the temporary imprint in the first dental impression material.

[0048] After such processing, the impression tray is replaced in the person's mouth to ensure a good fit between the teeth and the temporary imprint. The second dental impression material is then injected into the cavity through the openings and forced through the through holes into the temporary imprint to form a final imprint around the teeth. The final imprint, which can then be used, for example, to cast a dental model, is then removed from the person's mouth.

[0049] The method of the present invention can be performed, for example, by a dentist. However, those skilled in the art will recognize that the method will most often be performed by a dentist's assistant or other non-medical individual (e.g., a dental laboratory worker). Thus, the method of the present invention is not a surgical, therapeutic, or diagnostic method, but rather is part of a process for obtaining a dental reconstruction model.

[0050] The inventors have found that the above method of the present invention provides excellent results. However, in some cases, the fit between the tooth and the temporary imprint may be too tight and the clearance between the tooth and the first dental impression material may not be sufficient for the second dental impression material to fully penetrate along the tooth, reducing the accuracy of the imprint to some extent. Therefore, the inventors propose that the temporary imprint may be slightly molded around the tooth of interest before application of the second dental impression material in order to remove material and increase the clearance. For this purpose, for example, a drilling device that is also used to establish fluid communication with the cavity may be used. In a more preferred embodiment, a specific molding tool may be used, as described below. In summary, preferably, in the method of the present invention, step (d) also includes a step of molding the temporary imprint with a molding tool to increase the clearance of at least one tooth within the temporary imprint.

[0051] A particular advantage of the present invention is that a particular efficient cleaning can thus be achieved, so that it is easy to remove contaminants and residues from the fabrication process, by simply pressurizing the temporary imprint through the openings with compressed air, which is for example easily available to most workers in the dental field.Thus, preferably in the method of the present invention, step d) also comprises the step of removing residues from the penetration process, by pressurizing a gas, preferably air, through the openings into the cavity and through the through holes into the temporary imprint.

[0052] Generally, it is preferred in the methods of the present invention to dry at least one tooth and the surrounding area of ​​the mouth prior to step (e), preferably using compressed air.

[0053] Those skilled in the art are familiar with suitable dental impression materials. The method of the present invention and the impression tray of the present invention are not limited to specific dental impression materials. Those skilled in the art can, for example, directly obtain the respective materials from specialized suppliers, and if necessary, adapt the shape of the dental impression tray to the properties of dental impression materials. For example, those skilled in the art can configure the volume and injection pressure of the cavity and the diameter of the through hole to match the physicochemical properties of the second dental material and allow sufficient flow.

[0054] The term dental impression material implies a representative suitability of the material, for example, coated wax, plastic composition or hardenable polymer compound, as understood by those skilled in the art. Among the wide variety of possible materials, the inventor considers that the use of silicone rubber compounds for the dental impression material is superior in most applications, since it usually allows a very accurate impression to be obtained without any health risks to the patient. As disclosed above, in order to obtain the best results and to allow efficient treatment, it is recommended in most cases that the viscosity of the second dental impression material, i.e. the impression material injected through the cavity and the through-hole, is lower than that of the first dental impression material. Such materials are freely available from common suppliers and are often labeled with an indicator such as "low viscosity". Accordingly, preferably, in the method of the present invention, the first dental impression material and / or the second dental impression material comprises silicone rubber, and / or the viscosity of the second dental impression material is lower than that of the first dental impression material.

[0055] The advantage of the method of the present invention is that it allows the use of tools available to dentists and / or dental laboratories.Thus, preferably in the method of the present invention, said drilling tool is a dental drill, the diameter of said drilling tool is preferably in the range of 2-5 mm, preferably in the range of 3-4 mm, and / or said shaping tool is a sickle probe or a scaler, preferably a sickle probe, and / or said injection device is a syringe.

[0056] Regarding the overall process of taking an impression, the inventors propose a specific procedure that generally gives good results. Specifically, preferably in the method of the present invention, in step (c), pressure is applied to the filled impression tray, preferably by biting with teeth, to improve the imprint of at least one tooth in the first dental impression material, and / or in steps (e) and (f), pressure is applied to the filled and remodeled impression tray, preferably by biting with teeth, to improve the fitting of at least one tooth in the temporary imprint. Similarly, preferably in the method of the present invention, in step (f), the second dental impression material is allowed to harden in a time range of 10 to 180 seconds, preferably in a time range of 20 to 60 seconds.

[0057] An advantage of the present invention is that excellent results can be obtained without the need for retraction cords. Although the use of retraction cords may be advantageous in certain applications and / or may provide some additional accuracy in the impression, it is clearly preferred for most applications not to use retraction cords, as this results in a very time-efficient process that is often considered more comfortable for the patient. Thus, preferably, in the method of the present invention, no retraction cords are used to prepare at least one tooth prior to step (f).

[0058] The advantage of the present invention is that no unnecessary peeling force is applied between the first dental impression material and the impression tray.However, the inventor also proposes to use an adhesive to promote bonding, since it may be beneficial to avoid delamination caused by vibrations, for example by a drill, during the penetration process, especially when using a flat base surface.Therefore, preferably, in the method of the present invention, in step (b), an adhesive is used to promote bonding between the first dental impression material and the base surface.

[0059] Those skilled in the art will appreciate that the above-mentioned advantages of the method of the present invention are transferable to the process of producing a dental prosthesis or dental reconstruction. Thus, the process of producing a dental prosthesis, in particular a crown, of the present invention comprises: The method of taking a dental impression of the present invention comprises the steps of: (h) preparing a dental prosthesis for at least one tooth based on the final imprint or a model prepared from the final imprint.

[0060] In view of the above, the present invention also relates to a dental prosthesis. In particular, the present specification discloses a dental prosthesis made by the process of the present invention.

[0061] Those skilled in the art will appreciate that the present invention also relates to the use of impression trays as detailed above. More precisely, this specification also discloses the use of impression trays of the present invention for taking dental impressions.

[0062] Finally, the inventors propose that the impression trays of the present invention are most conveniently provided in the form of a specific kit that also provides other elements required to carry out the method of the present invention. Thus, the dental impression-taking kits disclosed herein include one or more impression trays of the present invention; one or more drilling tools and / or one or more drilling heads for the drilling tools; and optionally one or more forming tools.

[0063] Preferably, the kit of the present invention further comprises: First dental impression material and / or a second dental impression material; The first dental impression material and / or the second dental impression material are preferably provided in an injection device.

[0064] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. [Brief description of the drawings]

[0065] [Figure 1] FIG. 1 shows two impression trays, not of the present invention, configured for placement on the upper and lower jaws of a person's mouth. [Diagram 2] FIG. 2 is a first perspective view showing an example of an impression tray of the present invention in a preferred embodiment. [Diagram 3] FIG. 3 is a second perspective view of the impression tray of FIG. [Figure 4] FIG. 4 is a third perspective view of the impression tray of FIGS. 2 and 3. [Diagram 5] FIG. 5 is a cross-sectional view of a method of the present invention using an impression tray of the present invention, showing a first point in the method in a preferred embodiment. [Figure 6] FIG. 6 is a cross-sectional view of a method of the present invention using an impression tray of the present invention, showing a second point in the method in a preferred embodiment. [Figure 7] FIG. 7 is a cross-sectional view of a method of the present invention using an impression tray of the present invention, showing a third point in the method in a preferred embodiment. [Figure 8] FIG. 8 is a cross-sectional view of a method of the present invention using an impression tray of the present invention, showing a fourth point in the method in a preferred embodiment. [Figure 9] FIG. 9 shows an example of a punching and forming tool useful in the method of the present invention.

[0066] 1 shows two impression trays 10 that include common elements rather than the impression tray of the present invention and that can be used to take dental impressions using prior art methods. These impression trays 10 include a base element 12 having a base surface 14 bounded by the first boundary element 16 and the second boundary element 18, which are disposed on the base element 12 to form a receiving tray 20 configured to receive a first dental impression material 22.

[0067] 2, 3 and 4 are schematic diagrams of the impression tray 10 of the present invention in three different views. Similar to the impression tray 10 of FIG. 1, the impression tray 10 includes a base element 12 having a base surface 14, which is disposed between the first boundary element 16 and the second boundary element 18 to form a receiving tray 20. The impression tray 10 includes a cavity 24 in the base element 12 that extends below the base surface 14. The resulting base layer 26 separates the cavity 24 from the receiving tray 20 and has an opening 28 in fluid communication with the cavity 24. In this embodiment, the impression tray 10 is made entirely of polypropylene and is made by injection molding. The impression tray 10 includes a base element 12 made of a single piece, and the base surface 14 has a plurality of macroscopic protrusions (not shown) that extend uniformly over the entire surface area.

[0068] The first boundary element 16 is a boundary wall and has a number of holes that allow the first dental impression material to release pressure when a temporary impression is taken. In one example of an impression tray 10, the cavity 24 extends entirely below the base surface 14 and is airtight except for one opening 28. The opening 28 extends from the cavity 24 through the base element 12 to the outer surface of the impression tray 10 and connects with a tube 32 that is part of a handle 34.

[0069] In a preferred embodiment of the impression tray 10 shown, the first boundary element 16, the second boundary element 18, the tube 32 and the handle 34, as well as part of the base element 12, are made from a metal, for example aluminium, while the base layer 26 and the base surface 14 are made from a plastic, for example polypropylene, and are designed to be removable and replaceable, making it possible to realise a partially reusable impression tray 10.

[0070] Figures 5 to 8 show, in schematic cross-sectional views, the use of the impression tray 10 shown in Figures 2 to 4 in a method for taking a dental impression of the present invention at various stages of the method. Figure 5 shows the impression tray 10 prior to application of the first dental impression material 22.

[0071] FIG. 6 shows the impression tray 10 having temporary imprints of teeth within the first dental impression material 22 when the relatively high viscosity silicone rubber is allowed to harden in a person's mouth for approximately 45 seconds.

[0072] FIG. 7 shows the result of a drilling process in which the first dental impression material 22 and the underlying base layer 26 have been penetrated with a drilling tool 36 to form through holes 38 that establish fluid communication between the cavity 24 and the temporary imprint.

[0073] 8 shows the impression tray 10 with the final imprint after removal from the person's mouth. It can be seen that the second dental impression material 30 (here a relatively low viscosity silicone rubber) has been injected into the temporary imprint through the openings 28, the cavities 24 and the through holes 38, conforming precisely to the shape of the teeth.

[0074] In the method shown in Figures 5-8, tooth clearance in the temporary imprint was increased before application of the second dental impression material 30, and residues from the drilling and molding steps were removed by cleaning the impression tray 10 with compressed air injected for 10 seconds through the opening 28. The final impression obtained in Figure 8 can be used, for example, to make a model that can be used in the fabrication of a dental prosthesis.

[0075] FIG. 9 shows an example of a punch tool 36 and a forming tool 40 that can be used in a preferred embodiment of the method of the present invention. [Explanation of symbols]

[0076] 10 Impression tray 12 Base Elements 14 Base Surface 16 First boundary element 18 Second boundary element 20 Receiving Tray 22 The first dental impression material 24 Cavity 26 Base Layer 28 Opening 30 Second Dental Impression Material 32 Tube 34 Handle 36 Drilling tools 38 Through hole 40 Forming tools

Claims

1. A base element (12) having a base surface (14), a first boundary element (16), and a second boundary element (18), wherein the first boundary element (16) and the second boundary element (18) are disposed on the base element (12) to form a receiving tray (20) configured to receive a first dental impression material (22) between the first boundary element (16), the base surface (14), and the second boundary element (18), the base element (12) has a cavity (24) that at least partially extends beneath the base surface (14), and the cavity (24) and the receiving tray (20) are separated by a base layer (26) of the base element (12), the base element (12) has an opening (28) configured to be in fluid communication with the cavity (24) to inject a second dental impression material (30) into the cavity (24), An impression tray (10) for obtaining a dental impression of at least one tooth.

2. The base element (12) and the base layer (26) are made of a rigid material, preferably a metallic material, a ceramic material, or a rigid plastic material, The impression tray (10) according to claim 1.

3. The base element (12) consists of a single part or two or more parts, the base layer (26) of the base element (12) is removably detachable from other parts of the base element (12) reversibly and non-destructively, the base layer (26) is preferably an exchangeable part, the other parts of the base element (12) are preferably reusable parts, The impression tray (10) according to claim 1 or 2.

4. The cavity (24) is centered beneath the base surface (14), preferably extending over the entire length of the base surface (14), the width of the cavity (24) is preferably in the range of 20% to 80%, preferably 30% to 70%, more preferably 40% to 60% of the width of the base surface (14), The impression tray (10) according to claim 1 or 2.

5. The cavity (24) is airtight except for the opening (28), The impression tray (10) according to claim 1 or 2.

6. The opening (28) is connected to a tube (32), Preferably, the tube (32) is configured to receive an injection element of an injection device, preferably a syringe, and / or preferably the tube (32) is part of a handle (34) that facilitates handling of the impression tray (10), in particular placement in and removal from the oral cavity. The impression tray (10) according to claim 1 or 2.

7. (a) preparing the impression tray (10) according to claim 1 or 2; (b) filling the receiving tray (20) with a first dental impression material (22) to obtain the filled impression tray (10); (c) placing the impression tray (10) filled such that at least one tooth is disposed within the first dental impression material (22) into a human oral cavity to obtain at least one provisional imprint within the first dental impression material (22); (d) removing the impression tray (10) having the provisional imprint from the oral cavity, preferably at the bottom of the provisional imprint, penetrating the first dental impression material (22) together with the underlying base layer (26) using a piercing tool (36) to form a through-hole (38), establishing fluid communication between the cavity (24) and the provisional imprint to obtain the filled and modified impression tray (10); (e) returning the filled and modified impression tray (10) into a human oral cavity such that at least one tooth is re-disposed within the provisional imprint; (f) injecting a second dental impression material (30) into the cavity (24) through the opening (28), thereby pushing the second dental impression material (30) through the through-hole (38) into the provisional imprint and conforming it to the shape of at least one tooth to form a final imprint; (g) removing the impression tray (10) having the final imprint from a human oral cavity. A method for obtaining a dental impression of at least one tooth using the impression tray (10) according to claim 1 or 2.

8. Step (d) also includes shaping the provisional imprint using a shaping tool (40) to increase the clearance of at least one tooth within the provisional imprint, and / or The method according to claim 7 also includes a step of removing the residue by penetration, wherein the step (d) pressurizes a gas, preferably air, into the cavity (24) through the opening (28) and into the temporary imprint through the through-hole (38). The method according to claim 7.

9. The method according to claim 7, wherein the viscosity of the second dental impression material (30) is lower than the viscosity of the first dental impression material (22).

10. The steps of the method for obtaining a dental impression according to claim 7, and (h) a step of manufacturing at least one dental prosthesis for a tooth based on the final imprint or a model produced from the final imprint. A process for manufacturing a dental prosthesis, particularly a dental crown.

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