DE102021120277B4 - Dental prosthesis implant containing a mesostructure with shape memory effect - Google Patents

Abstract

Dental prosthesis implant comprising a dental implant containing an implant body and an abutment, a dental prosthesis element and a mesostructure arranged between the abutment and the dental prosthesis element, which contains a polymer with thermoresponsive shape memory properties, wherein the abutment is arranged in a recess of the mesostructure and the dental prosthesis element at least partially surrounds the mesostructure, wherein the dental prosthesis element only partially surrounds the mesostructure, so that the mesostructure is exposed in an area which is intended for contact with the gums in the intraorally placed dental prosthesis implant.

Description

field of the invention

The present invention relates to a dental prosthesis implant comprising a mesostructure which has a recess suitable for receiving the abutment of a dental implant and is suitable for arrangement between the abutment and a dental prosthesis element, wherein the mesostructure contains a polymer with thermoresponsive shape memory properties.

State of the art

A dental implant consists of an implant body that is screwed into the jawbone and represents the tooth root replacement, and an abutment for connecting to a visible dental prosthesis element such as a crown or bridge. The dental prosthesis element is screwed onto the abutment after the dental implant has healed.

Common materials for dental implants are titanium and titanium alloys. Abutments made of these materials are screwed onto the implant body after healing. The dental implant is therefore made of two parts. The screwed connections are never gap-free due to manufacturing tolerances. Bacteria can nest in the micro-gaps, and micro-movements of the parts against each other can release metal particles that accumulate in the surrounding tissue. Many dental implants lead to biological complications with peri-implant bone loss caused by inflammation as a result of bacterially caused peri-implantitis or a foreign body reaction, so there is a risk of implant loss.

Ceramic dental implants are becoming increasingly popular on the market due to their better biocompatibility. Due to the brittleness of ceramics, screw-on solutions are technically demanding and associated with high manufacturing costs. For this reason, one-piece ceramic implants are mainly offered, in which the implant body and abutment are made from one piece. The dental prosthesis element is then glued to the abutment. In order to completely fill the gap between the dental prosthesis element and the abutment, an excess of cement is required, which comes out when the dental prosthesis element is inserted and must be completely removed. However, this proves to be difficult, as the crown edge is usually deep below the gum line and a second surgical procedure is therefore necessary to remove the excess cement. In practice, this step represents the greatest obstacle to the use of ceramic implants.

EP 3 520 730 A1 describes a holding device for dental prosthetic elements, with a dental implant that has an implant shaft for placement in the jawbone and an implant head for placement in the gums, and an intermediate element that can be connected to the implant head for receiving the dental prosthetic element, wherein the intermediate element can consist of a material with a higher elasticity than the dental implant. The intermediate element is intended for placement at least substantially within the gums and is preferably screwed to the dental implant. The dental prosthetic element can be connected to the intermediate element by bonding with cement. By using the intermediate element, it is possible to move the crown edge to a clinically accessible area so that there is no excess cement to be removed in an area under the gum line.

Further state of the art is the US 2020 / 0 297 463 A1 and JP 2004- 337 419 A known.

Problems to be solved by the invention

The implant systems available in the state of the art have disadvantages. Either dental prosthetic elements are screwed onto the abutment, which can lead to infections due to micro-gaps, or they are attached by gluing using an intermediate element.

Due to the disadvantages of the state of the art, there is a need for improved implant systems.

It is the object of the present invention to provide a cost-effective, yet high-quality and, above all, safe solution for attaching dental prosthetic elements to implants. In particular, it is the object of the present invention to provide a screw-free and cement-free fastening system.

Summary of the Invention

The object was achieved by providing a dental prosthesis implant with an improved element between the abutment and the dental prosthesis element. This intermediate element is referred to as a mesostructure in the present invention.

The mesostructure contains shape memory polymers and is characterized by a shape memory effect.

The subject matter of the present invention is a dental prosthesis implant comprising a dental implant containing an implant body and an abutment, a dental prosthesis element and a mesostructure arranged between the abutment and the dental prosthesis element, which contains a polymer with thermoresponsive shape memory properties, wherein the abutment is arranged in a recess of the mesostructure and the dental prosthesis element at least partially surrounds the mesostructure, wherein the dental prosthesis element only partially surrounds the mesostructure, so that the mesostructure is exposed in an area which is intended for contact with the gums in the intraorally placed dental prosthesis implant.

Advantages of the invention

The mesostructure has the advantage that the high degree of precision fit between the abutment and the mesostructure creates a load-stable, bacteria-tight bond, thus eliminating the need for cement, which is required for conventional ceramic implants.

The mesostructure can be connected to the abutment by mechanical forces, especially by static friction.

The expanded form of the mesostructure can be “stored” in a stable manner by cooling it, for example to room temperature.

By using the mesostructure, mechanical properties can be adjusted, such as flexibility, so that the mesostructure can serve as a mechanical buffer. This can prevent biomechanical overload and thus implant loosening or loss.

The mesostructure with appropriate shape memory properties can be adapted to the individual patient and produced cost-effectively and with high quality using a 3D printing process.

Description of the characters

• 1 shows a mesostructure used in the present invention in longitudinal section with dimensions.
• 2A , 2B and 2C show a mesostructure used in the present invention in the external view, top view and internal view, respectively.
• 3A shows a mesostructure used in the present invention after printing and post-curing.
• 3B shows the mesostructure 3A which is mounted on an abutment.
• 3C shows the mesostructure 3A , which after expansion by heating and subsequent storage in the refrigerator to the 3B The abutment used was placed on top and shrunk by heating.

embodiments of the invention

The present invention relates to a dental prosthesis implant.

The mesostructure is designed to be inserted between the abutment of a dental implant and a dental prosthesis. The dental implant and the dental prosthesis are conventional products and can be made from commercially available materials.

The dental implant has an elongated, substantially cylindrical implant body and an elongated, substantially cylindrical abutment which is arranged on the round and flat upper side of the implant body, wherein the implant body preferably has a larger diameter than the abutment at least at the base of the abutment, whereby the upper side of the implant body is partially exposed. In the present invention, the longitudinal direction is predetermined by the orientation of the two elongated parts of the dental implant, namely the implant body and the abutment. In the longitudinal direction, the dental implant is inserted into the jaw, the recess of the mesostructure receives the abutment and the dental prosthesis element is placed on top.

In the present invention, the term “diameter” refers to a dimension transverse to the longitudinal direction of the preferably substantially cylindrical components, namely implant body, abutment and recess of the mesostructure.

In the present invention, the terms "top", "bottom", "upper", "lower" and the like refer to a dental prosthesis implant in the patient's lower jaw, where the dental implant, the mesostructure and the dental prosthesis element are arranged from bottom to top. In the case of a dental prosthesis implant in the upper jaw, the terms are reversed accordingly.

The implant body is designed to be placed in the jawbone and the abutment in the gums. When placed intraorally, the abutment protrudes above the jawbone and the area of the upper side of the implant body not occupied by the abutment attachment is exposed. The dental implant is preferably made of zirconium oxide, titanium or titanium alloys. In the case of dental implants made of zirconium oxide, The ceramic workpieces used are those with outstanding material properties in terms of their biocompatibility, stability and aesthetics. Zirconia exhibits properties that are comparable to metals or in some cases even superior to them. As a ceramic, it is corrosion-free and is characterized by high flexural strength and fracture toughness.

The dental prosthesis element such as a crown or bridge can consist of zirconium oxide, feldspar ceramic, glass ceramic, Li-disilicate ceramic, polymer-infiltrated ceramic or organic polymers. In one embodiment, the dental prosthesis element consists of an organically modified silica (hetero)polycondensate (ORMOCER ^® ) or a composite comprising an organically modified silica (hetero)polycondensate and a filler.

The mesostructure together with the dental implant and the dental prosthesis element results in the dental prosthesis implant according to the invention.

The process of creating the dental implant is a non-medical procedure; it can be performed entirely outside the human body.

mesostructure

1. (i) Die Mesostruktur besitzt auf ihre Unterseite eine zur Aufnahme des Abutments eines Dentalimplantats geeignete Ausnehmung. Als Stützpfeiler auf dem Dentalimplantat sind Abutments länglich und beispielsweise zylinderförmig mit einem kreisrunden oder ellipsoiden Querschnitt. Ihr Durchmesser ist einerseits so groß, dass sie stabil mit dem Dentalimplantat verbunden sind und mechanische Belastungen aushalten. Andererseits ist ihr Durchmesser deutlich geringer als der Durchmesser des darauf anzubringenden Zahnersatzelements. Ein Abutment ist einerseits lang genug, um die Krone oder Brücke stabil zu fixieren. Andererseits ist die Länge des Abutments durch die vorgegebene Höhe eines Zahnes begrenzt. Diese Vorgaben spiegeln sich entsprechend in der Größe und Form der Ausnehmung der Mesostruktur wider.
2. (ii) Die Mesostruktur ist zur Anordnung zwischen dem Abutment und einem Zahnersatzelement geeignet. Durch diese Vorgabe sind Größe und Form der Mesostruktur weiter eingeschränkt. Insbesondere wird dadurch festgelegt, dass die Abmessungen der Mesostruktur die Abmessungen eines Zahnersatzelements nicht übersteigen dürfen.

The mesostructure used in the present invention has the following structural specifications (i) and (ii) regarding size and shape:

1. (i) The mesostructure has a recess on its underside suitable for receiving the abutment of a dental implant. As a support pillar on the dental implant, abutments are elongated and, for example, cylindrical with a circular or ellipsoidal cross-section. On the one hand, their diameter is large enough to be firmly connected to the dental implant and to withstand mechanical loads. On the other hand, their diameter is significantly smaller than the diameter of the dental prosthesis element to be attached to it. On the one hand, an abutment is long enough to securely fix the crown or bridge. On the other hand, the length of the abutment is limited by the specified height of a tooth. These specifications are reflected accordingly in the size and shape of the recess of the mesostructure.
2. (ii) The mesostructure is suitable for placement between the abutment and a dental prosthesis element. This requirement further restricts the size and shape of the mesostructure. In particular, it stipulates that the dimensions of the mesostructure must not exceed the dimensions of a dental prosthesis element.

The specifications (i) and (ii) largely determine the shape and size of the mesostructure and the recess. For example, the mesostructure can resemble a protective cap for an abutment.

Preferably, the underside of the mesostructure is flush with the exposed upper side of the implant body, i.e. with the area of the flat upper side of the implant body that is not occupied by the abutment attachment. The contact surfaces therefore have the same diameter. Preferably, the diameter of the abutment increases from the contact point upwards and decreases again further up, so that in the lower area of the mesostructure there is a circumferential area with a larger diameter than in the adjacent areas above or below (cf. 1 ). This area with a larger diameter is referred to herein as the circumferential collar. The top of the circumferential collar can serve as a support for the dental prosthesis element, for example the crown edge. It may be preferred that the circumferential collar extends outwards, i.e. in a direction such as in 1 shown longitudinal sectional view, tapers to a point, wherein the outward-running surfaces of the collar are preferably concave or oblique.

1. (A) Die Mesostruktur kann vollständig von dem Zahnersatzelement bedeckt sein, so dass kein Bereich der Mesostruktur freiliegt. Vollständig bedeckt heißt hier, dass in einer Seitenansicht des Zahnersatzimplantats, also senkrecht zur Längsrichtung des Implantatkörpers, kein Bereich der Mesostruktur sichtbar ist.
2. (B) Die Mesostruktur kann unvollständig von dem Zahnersatzelement bedeckt sein, so dass ein Bereich der Mesostruktur freiliegt, also in einer Seitenansicht sichtbar ist. Vorzugsweise liegt der untere Bereich der Mesostruktur frei. Der freiliegende Bereich ist bei Vorhandensein eines oben beschriebenen umlaufenden Kragens der Bereich, der sich von der Oberseite des umlaufenden Kragens bis zur Kontaktstelle mit dem Implantatkörper erstreckt.
   • (B-1) In einer Ausgestaltung der Ausführungsform (B) ist der freiliegende Bereich der Mesostruktur unterhalb des Zahnfleischrandes angeordnet und damit im intraoral gesetzten Zustand unsichtbar.
   • (B-2) In einer anderen Ausgestaltung der Ausführungsform (B) steht der freiliegende Bereich der Mesostruktur über den Zahnfleischrand hervor und ist damit im intraoral gesetzten Zustand sichtbar. In diesem Fall ist die Mesostruktur vorzugsweise gefärbt.

The mesostructure is suitable for arrangement between the abutment and a dental prosthesis element. In other words, the dental prosthesis element is placed on the previously formed composite of dental implant with abutment and mesostructure applied thereon, whereby a dental prosthesis implant is obtained. The dental prosthesis implant is a composite of dental implant, mesostructure and dental prosthesis element and can be present in the following embodiments (A) and (B):

1. (A) The mesostructure can be completely covered by the dental prosthesis element so that no area of the mesostructure is exposed. Completely covered here means that in a side view of the dental prosthesis implant, i.e. perpendicular to the longitudinal direction of the implant body, no area of the mesostructure is visible.
2. (B) The mesostructure can be incompletely covered by the dental prosthesis element, so that a region of the mesostructure is exposed, i.e. visible in a side view. Preferably, the lower region of the mesostructure is exposed. In the presence of a circumferential collar as described above, the exposed region is the region that extends from the top of the circumferential collar to the contact point with the implant body.
   • (B-1) In one embodiment of the embodiment (B), the exposed region of the mesostructure is arranged below the gum line and is thus invisible when placed intraorally.
   • (B-2) In another embodiment of the embodiment (B), the exposed area of the mesostructure protrudes above the gum line and is thus visible in the intraoral state. In this case, the mesostructure is preferably colored.

The dental prosthesis element is manufactured to match the mesostructure using conventional methods. The dental prosthesis element can be connected to the mesostructure by gluing, in particular with cement or another adhesive. Depending on the design, any cement or adhesive residues that may emerge appear in an area that is only slightly below the gum line or not at all. In design (B-1), the area between the mesostructure and the dental prosthesis element is preferably only slightly below the gum line.

In particular, this area is at most 1 mm below the gum line. This makes it possible to easily remove the cement or adhesive residues. In embodiment (B-2) this is even easier because the dental prosthesis element does not extend below the gum line. By moving the crown edge to a level above the gum line using the mesostructure, the crown edge is then easily accessible for cement removal. The use of the mesostructure thus makes it possible to remove any cement and/or adhesive residues smoothly and without leaving any residue, thus avoiding subsequent constant irritation of the gums. For this reason, embodiment (B) is preferred.

The potential elasticity of the mesostructure can create a natural biomechanical damping function that works in a similar way to the periodontium in a natural tooth. This prevents mechanical overload, e.g. when chewing or grinding, which is another advantage over a fully ceramic system.

The abutment protrudes into the recess of the mesostructure. This enables good fixation, in particular a form-fitting fixation between the dental prosthesis element and the dental implant. The mesostructure is preferably designed in such a way that it can surround the attachment of the abutment, in particular laterally. In particular, the attachment is completely surrounded laterally by the mesostructure.

The mesostructure is preferably conical with recess diameters of 2.4 to 2.7 or 2.7 to 3.0 mm and a wall thickness of 0.8 to 1.0 mm (cf. 1 ).

The mesostructure contains a polymer with thermoresponsive shape memory properties, or shape memory polymer for short. This means that the mesostructure also has thermoresponsive shape memory properties. The mesostructure preferably contains at least 50 percent by weight of at least one shape memory polymer. The mesostructure can therefore be expanded without cracking by heating it to a temperature above body temperature. The expanded mesostructure can preferably be "frozen" so that it retains its shape below body temperature, e.g. at room temperature. This ensures the necessary storage stability when not applied directly. After being inserted into the oral cavity and heated to body temperature, the mesostructure contracts back into its original shape due to the shape memory effect, "shrinking" onto the abutment, i.e. the abutment is held in place precisely by shrinking the mesostructure. In this way, a solid abutment-mesostructure bond is created, so that in one embodiment of the invention no adhesive is required between the abutment and the mesostructure.

shape memory polymer

Thermoresponsive shape memory polymers undergo a change in shape and other properties above a characteristic temperature known as the switching temperature. Shape memory polymers are generally specified to include a desired state shape ("desired shape") and an actual state shape ("actual shape"). The desired shape is the shape to which the shape memory polymer attempts to return when above the switching temperature. The actual shape is the shape to which the shape memory polymer is deformed above the switching temperature. The shape memory polymer can be stored in the as-is shape for extended periods of time as long as the shape memory polymer is not exposed to the temperature that triggers recovery of the shape memory polymer's permanent shape.

Shape memory polymers can consist of at least two polymer components or preferably of one polymer component with different segments. On the one hand, these are “hard” phases or segments, which also function as network points, and on the other hand, “soft” phases or segments, which connect the network points with each other and are also referred to as switching segments, which high temperatures are elastic and exist in an amorphous form, while at low temperatures they are rigid and exist in a semi-crystalline or vitrified form. Such shape memory polymers can be programmed in terms of their shape by heating them in the desired shape to a temperature which corresponds at least to the so-called switching temperature at which the phase transition (glass transition or melting transition) of the soft or switching segments takes place. At such a temperature, the polymer is then deformed into its actual state, after which it is cooled to its so-called shape fixing temperature, which corresponds to the crystallization temperature or glass transition temperature of the soft or switching segments and is usually lower than the switching temperature. The soft or switching segments are then again in a semi-crystalline or vitrified form, so that the shape is retained. When the temperature is increased to the switching temperature, the soft segments (switching segments) are converted back into their amorphous form so that they can no longer counteract the restoring force induced by the hard component (network points) and the shape memory polymer returns to its original shape, thus "reversing" the mechanical deformation.

The mesostructure can contain such a shape memory polymer. The shape memory polymer is in the desired shape at body temperature. The recess of the mesostructure is adapted in shape and size to the abutment onto which the mesostructure is to be placed. In the desired state, the shape and size of the recess of the mesostructure correspond to the shape and size of the abutment. It can be preferred that the size of the recess, in particular its diameter, is smaller than the size, in particular the diameter, of the abutment. The switching temperature of the shape memory polymer is preferably above body temperature.

The mesostructure is heated above the switching temperature of the shape memory polymer, for example to a temperature in the range of 45 °C to 80 °C, so that an enlargement of the recess can be achieved as follows: The recess of the mesostructure, in particular its diameter, increases either because the heated and softened mesostructure deforms and as a result returns to the actual state of its own accord, or because the heated and softened mesostructure is placed on a structure that is larger than the abutment and is thus deformed to the actual state. The actual shape can then be stably fixed by cooling to the shape fixing temperature, for example to room temperature (about 21 °C) or in the refrigerator (about 4 °C). The mesostructure in the actual shape can deform back from the actual shape to the pre-programmed target shape due to the body heat of the patient in the oral cavity.

In the present invention, the target temperature is the temperature at which the mesostructure assumes the target state. The target temperature is usually the body temperature in the mouth, which can fluctuate between 32 °C and 38 °C, in particular between 35 °C and 37.5 °C. The deformation temperature is a temperature at which the mesostructure assumes the actual state, that is, a state deformed compared to the target state. The deformation temperature is preferably in the range of 45 °C to 80 °C. The shape-fixing temperature is a temperature which is below the target temperature and at which the actual state of the mesostructure is maintained. The shape-fixing temperature is preferably in the range of 0 °C to 25 °C, more preferably in the range of 0 °C to 10 °C.

Shape memory polymers are known in the art and include thermoplastics, thermosets, interpenetrating networks, semi-interpenetrating networks, or blended networks. The polymers may be a single polymer or a blend of polymers. The polymers may be linear or branched thermoplastic elastomers with side chains or dendritic structural elements. Suitable polymer components for forming a shape memory polymer include: polyphosphazenes, polyvinyl alcohols, polyamides, polyester amides, polyamino acid(s), polyanhydrides, polycarbonates, polyacrylates, polyalkylenes, polyacrylamides, polyalkylene glycols, polyalkylene oxides, polyalkylene terephthalates, polyorthoesters, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyesters, polylactides, polyglycolides, polysiloxanes, polyurethanes, polyethers, polyether amides, polyether esters, and copolymers thereof. Examples of suitable polyacrylates include polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, polyhexyl methacrylate, polyisodecyl methacrylate, polylauryl methacrylate, polyphenyl methacrylate, polymethyl acrylate, polyisopropyl acrylate, polyisobutyl acrylate and polyoctadecyl acrylate.

The shape memory polymer can be selected from the group of thermoplastic and/or thermoelastic polymers including thermoplastic elastomers. Suitable thermoplastically processable shape memory polymers are linear block copolymers, in particular from the group of polyurethanes, block copolymers of polyethylene terephthalate and polyethylene oxide, block copolymers of polystyrene and poly(1,4-butadiene), ABA triblock copolymers of poly(2-methyl-2-oxazoline) (A block) and polytetrahydrofuran (B block), Multiblock copolymers made of polyurethanes with poly(ε-caprolactone) switching segment, block copolymers made of polyethylene terephthalate and polyethylene oxide, and block copolymers made of polystyrene and poly(1,4-butadiene). Other examples of shape memory polymers are polyurethane elastomers whose hard segment-forming phase is made up of a diisocyanate, such as methylene diphenyl diisocyanate (MDI), isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HMDI), toluene-2,4-diisocyanate (TDI), 1,5-pentane diisocyanate (PDI) or the like, and a diol, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol or the like. Both the aforementioned diisocyanates and the polyols can be used individually or in any mixture with one another. In thermoplastic polyurethane elastomers with thermoresponsive shape memory effects, the soft segment can be, for example, an oligoether, in particular from the group polyethylene oxide, polypropylene oxide, polytetramethylene ether glycol (PTMEG) and a combination of 2,2-bis(4-hydroxyphenyl)propane and propylene oxide. Furthermore, the soft segment can be, for example, an oligoester, in particular from the group polyethylene adipate, polypropylene adipate, polybutylene adipate, polypentylene adipate and polyhexalene adipate, although other oligoesters have also proven useful. The oligoesters can be formed by reacting aliphatic or aromatic dicarboxylic acids with glycols having 2 to 10 carbon atoms. The dicarboxylic acids can be used individually or as mixtures, e.g. in the form of a succinic, glutaric and adipic acid mixture. To produce the polyester polyols, it may be advantageous to use the corresponding dicarboxylic acid derivatives, such as carboxylic acid diesters with 1 to 4 carbon atoms in the alcohol residue, carboxylic acid anhydrides, carboxylic acid chlorides or the like, instead of dicarboxylic acids. Examples of polyhydric alcohols include: The polyhydric alcohols can be used alone or, if appropriate, in a mixture with one another. The polyester polyols can have molecular weights between 400 g/mol and 10,000 g/mol.

The mesostructure can preferably be produced using a printing process. Therefore, shape memory polymers are preferred which can be obtained from starting compounds with at least one organically polymerizable group or a reactive ring. An organically polymerizable group is to be understood here as meaning that this group is accessible to a polyreaction in which reactive double bonds or rings are converted into polymers under the influence of heat, light or ionizing radiation. During polymerization, neither molecular components are split off nor do they migrate or rearrange. These groups should particularly preferably also be accessible to a thiol-ene polyaddition when a thiol is added. Alternatively, they can be accessible to a ring-opening polymerization. Examples of these are norbornene groups. The reactive double bond can be selected as desired and is, for example, a vinyl group or part of an allyl or styryl group. A group with a double bond which is accessible to a Michael addition and contains a methylene group activated as a result of its proximity to a carbonyl group is preferred. Among these, acrylic acid and methacrylic acid groups or derivatives thereof are preferred.

In one embodiment, the radiation-polymerizable material contains a starting component with cycloolefinic groups, a thiol with at least two thiol groups per molecule and an initiator and/or catalyst for the radiation-induced thiol-ene addition reaction between the thiol groups and a double bond of the cycloolefinic groups. The starting component can be a silicic acid (hetero)polycondensate modified with cycloolefinic groups. The thiol can contain at least two thiol groups per molecule or can be a mixture of two trithiols. Examples of oligothiols for thiol-ene polyaddition are trimethylolpropane tri(3-mercaptopropionate) (TMPMP), trimethylolpropane trimercaptoacetate) (TMPMA), pentaerytritol tetra(3-mercaptopropionate) (PETMP), pentaerytritol tetramercaptoacetate) (PETMA), glycol dimercaptoacetate, 2, 3-di((2-mercaptoethyl)thiol-1 -propanethiol (DMPT), glycol di(3-mercaptopropionate), ethoxylated trimethylolpropane tri(3-mercaptopropionate), biphenyl-4-4''-dithiol, P-terphenyl-4,4''-dithiol, 4,4'-thiobisbezenethiol, 4,4'-dimercaptostilbene, benzene-1,3-dithiol, benzene-1,2-dithiol, Benzene-1,4-dithiol, 1,2-benzenedimethanethiol, 1,3-benzenedimethanethiol, 1,4-benzenedimethanethiol, 2,2'-(ethylenedioxy)diethanethiol; mercaptoethyl ether, 1,6-hexanedithiol, 1,8-octanedithiol and 1,9-nonanedithiol. A phosphine oxide, preferably a diphenylphosphine oxide and very particularly preferably 2,4,6-trimethylbenzoyldiphenylphosphine oxide (LTPO), can be added as an initiator and/or catalyst for the light-induced thiol-ene addition reaction.

In the present invention, it is particularly preferred that the starting compound with at least one organically polymerizable or reactive ring is an organically modified silica (hetero)polycondensate, i.e. an inorganic-organic hybrid polymer. An example of such a hybrid polymer is ORMOCER ^® . The term "silica (hetero)polycondensate" is intended to include both silica polycondensates and silica heteropolycondensates which, in addition to silicon, contain heteroelements such as B, Al, Zr, Zn, Ti and the like. The starting compound is a polysiloxane based on monomeric silanes which have one, two or three hydrolyzable groups. The silanes are functionalized with the above-mentioned organically polymerizable groups or reactive rings, for example with (meth)acrylic groups or cycloolefinic groups, such as norbornenyl groups.

production of the mesostructure

The production of the mesostructure and its shaping can be carried out using conventional methods, which include not only ablative processes but also additive processes.

The mesostructure can be made of grindable material. In this case, the mesostructure can be adapted to the anatomical situation before insertion or provided with a recess to accommodate the abutment.

The mesostructure is preferably produced by a 3D printing process, for example using the one-photon polymerization or two-photon polymerization (TPA) technique. One-photon polymerization may be preferred because larger areas can be solidified at once compared to TPA, allowing for very fast processing.

An example of a method for producing a mesostructure using a radiation-induced printing method according to the technique of the one-photon polymerization process is characterized in that the mesostructure is produced by solidifying a liquid or viscous material which contains a polysiloxane component which was formed by hydrolytic condensation of silanes with hydrolyzable groups and an organically polymerizable residue, and an initiator and/or catalyst for the radiation-induced polymerization of the organically polymerizable residue, wherein the solidification takes place by directing light from a radiation source onto an area of a surface of a substrate, wherein a layer of the liquid or viscous material located there is subjected to organic polymerization by the action of radiation and is thereby solidified, whereupon further layers of the liquid or viscous material, each of which is located on the layer of the last solidified material, are solidified with the aid of this radiation source.

The mesostructure is preferably produced using digital light processing (DLP) using starting compounds that preferably contain groups containing reactive C=C double bonds, such as (meth)acrylic or norbornenyl groups and/or ring-opening polymerizable groups. In addition to DLP technology, shaping can also be carried out using other additive light-curing processes, such as stereolithography (SLA), µ-stereolithography (µ-SLA), 2-photon polymerization (TPA), multi jet modeling (MJM), poly jet printing (PJP), CLIP processes (Continuous Liquid Interface Production), film transfer imaging (FTI, e.g. Admaflex Technology), lithography-based ceramic manufacturing (LCM), hot lithography or the TwoCure process or mask stereolithography (MSLA).

The printable material preferably has a viscosity of at most 50 Pa·s at room temperature. Polymerizability should preferably be possible at 385, 405 or 460 nm.

The shaping of the photosensitive, flowable material systems can be realized after adding various types of additives (for initiation, to avoid overpolymerization, for stabilization, etc.).

After 3D printing, the components can be washed with various solvents, preferably isopropanol, in an ultrasonic bath. The components can preferably be subsequently post-cured, for example photo-initiated with a flashlight device (optionally with protective gas), Spectramat, dental spotlight and/or high-intensity LED spotlight and/or thermally initiated in an oven, with an IR spotlight and/or microwave.

In addition to the light-curing processes, other processes such as Fused Deposition Modeling (FDM), Fused Film Fabrication (FFF), Selective Laser Sintering (SLS), Selective Laser Melting (SLM), Electron Beam Melting (EBM) can be used.

initiators

Initiators such as phosphine oxides or peroxides are additives for initiating radical polymerization. Preferably, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (LTPO) or dibenzoyl peroxide (DBPO) are used. Aliphatic photoinitiators can also be used, for example α-ketocarboxylic acids or their esters, ethyl pyruvic acid ester and aliphatic α-diketones such as 2,3-butanedione and 2,3-pentanedione. Mixtures of the various initiators can also be used advantageously. For example, a photoinitiator can be combined with a thermal initiator, with the photoinitiator being used for pre-crosslinking during 3D printing and the thermal initiator subsequently for post-curing in the oven. Two photoinitiators can also be used, with their absorption ranges coordinated so that that one photoinitiator splits during 3D printing and the second during post-curing with light of a wavelength that differs from the emission wavelength of the printer's LED.

fillers

Unfilled polymers or unfilled hybrid polymers can be used as the material basis for the mesostructures. Composites that contain polymers or hybrid polymers and fillers may be preferred.

Any filler can be used. Examples are primary particles in the nanometer range, which can be agglomerated to form larger particles or (fully) dispersed as required. Instead or in addition, larger particles can be added. Inorganic, organic, inorganic-organic, splinter-shaped, spherical or fibrous fillers can be used. Dental glass powders with particle sizes between 0.01 µm and 15 µm are particularly preferred as splinter-shaped fillers. SiO ₂ , TiO ₂ , ZnO, ZnS and ZrO ₂ nanoparticles with particle sizes between 2 nm and 200 nm are particularly preferred as spherical fillers. The fillers can be surface-modified to improve the bond between the filler particles and the cross-linked matrix. The surface modification preferably carries groups that can be polymerized into the organic network of the polymer.

UV absorbers and brighteners

UV stabilizers, particularly preferably inorganic and organic UV absorbers, can be used to counteract problems associated with so-called “overcuring.” Examples of inorganic UV absorbers are titanium oxide, zirconium oxide and zinc oxide. Examples of organic UV absorbers are benzophenones such as DHDMBP = 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone, Cyasorb UV-416 = 2-(4-benzoyl-3-hydroxyphenoxy)ethyl acrylate, Cyasorb UV-531 = 2-hydroxy-4-n-octoxy-benzophenone, Cyasorb UV-9 = 2-hydroxy-4-methoxy-ben zophenone, Chiguard BP-1 = 2,4-dihydroxybenzophenone, Chiguard BP-4 = 2-hydrox-4-methoxy-benzophenone-5-sulfonic acid and Chiguard BP-2 = 2,2',4,4'-tetrahydroxy-benzophenone; and benzotriazoles such as Tinuvin 327 = 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chloro-2H-benzotriazole, Chiguard 323 = 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate, Chiguard R-445 (benzotriazole), Chiguard 5431 = 2,2'-Methylene bis(6-( Tinuvin 2-(2H-benzotriazol-2-yl)-4,6-ditertpentyl-phenol, Chiguard 5411 = 2-(2'-hydroxy-5'-tert-octylphenyl)-benzotriazole and Chiguard 234 = 2-[2-hydroxy-3,5-di-(1,1-dimethylbenzyl)]-2H-benzotriazole.

Organic UV absorbers are preferred which have reactive groups such as (meth)acrylate groups for covalent bonding to the matrix (e.g. Chiguard 323). Surprisingly, DBPO (as well as structurally comparable initiators) also acts as an organic UV absorber.

Examples of optical brighteners are TBT = 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole), Uvitex OB- Eutex 127 = 1,1'-biphenyl-4,4'-bis[2-(methoxyphenyl)ethenyl], Eutex KCB = 2,2'-(1,4-naphthalenediyl)bisbenzoxazole, Eutex CBS = 1,1'-biphenyl-4,4'-bis[2-(sulphophenyl)ethenyl]disodium salt and Eutex KSN = 4,4-bis(5-methyl-2-benzoxazole)ethylene.

adhesive

A thin film of an adhesive can be used to create an additional chemical bond between the mesostructure and the abutment. The adhesive can be adapted to the dental implant (e.g. ZrO ₂ ) and the shape memory polymer or the composite of the mesostructure. Classic, commercially available organic systems or well-known ORMOCER ^® -based systems can be used. Examples include self-etching adhesives that contain silica (hetero)polycondensates that have both organically polymerizable groups, in particular (meth)acrylic groups, and phosphonate, sulfate or sulfonate groups.

This special adaptation results in an even more load-stable, bacteria-proof overall bond. In a preferred embodiment of the invention, the use of an adhesive makes the use of cement superfluous.

production of the dental implant

The method for producing a dental prosthesis implant according to the invention comprises the following steps (i) to (vi) in the order given.

Step (i) comprises providing a dental implant with an implant body and an abutment. The provision may be carried out entirely outside the patient's body. In this case, all subsequent steps may also be carried out outside the patient's body. Preferably, however, the provision comprises the int intraoral placement of the dental implant, i.e. insertion into the patient's jawbone. In this case, steps (iv) to (vi) are also carried out on the intraoral dental implant.

Step (ii) comprises providing a mesostructure used in the present invention. The mesostructure contains a shape memory polymer and a recess. The recess is adapted in shape and size to the abutment of the dental implant provided in step (i). The aim of this adaptation is preferably for the recess to accommodate the abutment as completely and precisely as possible. Preferably, the recess of the mesostructure is set so that it has a smaller volume at body temperature than is required to accommodate the abutment. In this way, a tension is generated when shrinking at body temperature. The mesostructure therefore wraps tightly around the abutment during shrinking due to tension, resulting in a precise, gap-free seal and a strong bond to the abutment.

Step (iii) comprises changing the temperature of the mesostructure from a target temperature to a deformation temperature and forming a deformed mesostructure with an enlarged recess diameter. Preferably, the target temperature is a temperature in the range of body temperature, which can in particular vary between 35 °C and 37.5 °C, and the deformation temperature is a temperature in the range of 45 °C to 80 °C.

Between step (iii) and step (iv), a step can be carried out which comprises cooling the mesostructure deformed in step (iii) to a shape-fixing temperature lower than the target temperature while maintaining the deformation of the mesostructure. The shape-fixing temperature is below body temperature and is a temperature in the range from 0 °C to 25 °, for example room temperature, and preferably a temperature in the range from 0 °C to 10 °C. At the shape-fixing temperature, the expanded mesostructure can be "frozen" in a dimensionally stable manner. This ensures the necessary storage stability when not applied directly.

Step (iv) involves uniting the mesostructure and the dental implant by receiving the abutment into the recess of the deformed mesostructure. In this step, the mesostructure is placed on the abutment.

Step (v) involves shrinking the deformed mesostructure at the target temperature to form an abutment-mesostructure bond. After being inserted into the oral cavity and warmed to body temperature, the mesostructure contracts back into its original shape due to the shape memory effect, whereby it "shrinks" onto the abutment, i.e. the abutment is precisely accommodated by shrinking the mesostructure, so that a solid abutment-mesostructure bond is created.

Step (vi) comprises attaching a dental prosthesis element to the abutment-mesostructure composite to form the dental prosthesis implant. The mesostructure preferably has a circumferential collar in the lower region, the upper side of which is preferably only slightly below the gum line when placed intraorally. The dental prosthesis implant has a recess and is placed on the mesostructure so that the lower edge of the dental prosthesis implant can rest on the upper side of the collar. This design makes it easy to remove any cement or adhesive residues that occur when attaching the dental prosthesis implant to the mesostructure. Alternatively, the recess of the dental prosthesis element can be adapted so precisely to the shape and size of the mesostructure that only a thin film of adhesive fits between the mesostructure and the dental prosthesis element and is required to attach the dental prosthesis element. In this case, there may be no adhesive residues or only such small amounts of them that removal of adhesive residues is not necessary or is not required.

examples

(A) Synthesis of resin system 1 (silane-based system)

• Zur Vorlage von 745,2 g (3,0 mol) 3-Glycidyloxypropyldimethoxysilan werden unter trockener Atmosphäre Triphenylphosphin als Katalysator, BHT als Stabilisator und anschließend 284,1 g (3,3 mol) Methacrylsäure zugetropft und bei 85 °C gerührt (ca. 1 Tag). Nach Zugabe von Essigester (300 ml/mol Silan) und H₂O zur Hydrolyse mit HCl als Katalysator wird bei 30 °C gerührt. Die Aufarbeitung erfolgt nach ca. mehrtägigem Rühren durch mehrmaliges Ausschütteln mit wässriger NaOH und mit Wasser und Filtration über hydrophobierten Filter. Es wird zunächst abrotiert und anschließend mit Ölpumpenvakuum abgezogen. Es resultiert ein flüssiges Harz ohne Einsatz von Reaktivverdünnern (Monomeren) mit einer Viskosität von ca. 3,5 - 5,5 Pa·s bei 25 °C.

In a first synthesis step, base resin (a) was prepared:

• Triphenylphosphine as a catalyst, BHT as a stabilizer and then 284.1 g (3.3 mol) of methacrylic acid are added dropwise to 745.2 g (3.0 mol) of 3-glycidyloxypropyldimethoxysilane under a dry atmosphere and stirred at 85 °C (approx. 1 day). After adding ethyl acetate (300 ml/mol silane) and H ₂ O for hydrolysis with HCl as a catalyst, the mixture is stirred at 30 °C. After stirring for several days, the mixture is worked up by shaking it out several times with aqueous NaOH and with water and filtering it through a hydrophobic filter. It is first evaporated in a rotary evaporator and then drawn off using an oil pump vacuum. The result is a liquid resin without the use of reactive diluents (monomers) with a viscosity of approx. 3.5 - 5.5 Pa s at 25 °C.

• Zur Vorlage von 131,1 g (0,50 mol) von Grundharz (a) werden unter Rühren bei ca. 90 °C ca. 68 g (1,0 mol) Cyclopentadien (CP) (durch Spaltung von Dicyclopentadien frisch hergestellt) zudestilliert und danach noch bei 90 °C weitergerührt. Die Umsetzung kann mittels NMR verfolgt werden. Die flüchtigen Bestandteile wie z. B. unumgesetztes Cyclopentadien werden im Ölpumpenvakuum bei Temperaturen bis zu 90 °C abgezogen. Es resultiert ein flüssiges Harz ohne Einsatz von Reaktivverdünnern (Monomeren) mit einer Viskosität von ca. 53 - 110 Pa·s bei 25 °C. Eine weitere Aufarbeitung ist in der Regel nicht erforderlich.

In a second synthesis step, resin system 1 was prepared:

• Approximately 68 g (1.0 mol) of cyclopentadiene (CP) (freshly prepared by splitting dicyclopentadiene) are distilled into 131.1 g (0.50 mol) of base resin (a) while stirring at approximately 90 °C, and then stirring is continued at 90 °C. The reaction can be monitored using NMR. The volatile components such as unreacted cyclopentadiene are removed in an oil pump vacuum at temperatures up to 90 °C. This results in a liquid resin without the use of reactive diluents (monomers) with a viscosity of approximately 53 - 110 Pa s at 25 °C. Further processing is generally not necessary.

(B) Preparation of the resin mixture for 3D printing

In resin system 1, 0.0005 mmol/g resin mixture (based on resin system + thiol) of absorber 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (TBT) is first dissolved with stirring (if necessary with a solvent, which is then removed again). The trithiol trimethylolpropane tri(3-mercaptopropionate) (TMPMP) (m molar ratio of SH:C=C = 0.9:1), in which the stabilizer pyrogallol (0.2 wt.% based on resin system + thiol) and the photoinitiator Lucirin TPO (1.0 wt.% based on resin system + thiol) were dissolved with stirring at 40 °C, is then added. The resulting resin mixture is used for 3D printing as part of a photo-induced thiol-ene polyaddition.

(C) 3D printing of mesostructures and placement on the ZrO ₂ implant

Based on the resin mixture prepared according to (B), the mesostructure was prepared with the 1 The parts were printed to the specified dimensions using a Rapidshape S 60 LED 3D printer (DLP principle) with a layer thickness of 50 µm and an exposure time of 31 s per layer at a light intensity of 6.15 W/m ² with the underside facing the build platform, washed, dried and post-cured with a flash light.

2A , 2B and 2C show a mesostructure used in the present invention in the external view, top view and internal view, respectively.

The 3A to 3C illustrate the steps of the procedure. 3A shows a mesostructure after printing and post-curing. 3B shows the “fitting” of the mesostructure from 3A by placing it on an abutment with a desired diameter, i.e. target diameter. 3C shows the mesostructure 3A which is placed on an abutment. The mesostructure was previously heated to about 50 °C and placed on an abutment with a larger diameter than the target diameter, thereby expanding it. The expanded structure was then stabilized in the refrigerator and then placed at room temperature on the 3C The abutment shown is placed with a target diameter and heated. The heating causes the mesostructure to "shrunk" onto the abutment.

In clinical practice, the “fitting” and “shrinking” of the mesostructure is preferably carried out intraorally on the placed dental implant.

Claims (8)

Dental prosthesis implant comprising a dental implant containing an implant body and an abutment, a dental prosthesis element and a mesostructure arranged between the abutment and the dental prosthesis element, which contains a polymer with thermoresponsive shape memory properties, wherein the abutment is arranged in a recess of the mesostructure and the dental prosthesis element at least partially surrounds the mesostructure, wherein the dental prosthesis element only partially surrounds the mesostructure, so that the mesostructure is exposed in an area which is intended for contact with the gums in the intraorally placed dental prosthesis implant. dental implant after claim 1 , wherein an adhesive film is contained between the abutment and the mesostructure and/or between the mesostructure and the dental prosthesis element. dental implant after claim 1 or 2 , whereby the implant body and the abutment are formed as one piece. Dental prosthesis implant according to one of the preceding claims, wherein the mesostructure is designed such that it completely surrounds the abutment. Dental prosthesis implant according to one of the preceding claims, wherein the mesostructure has, as a lower end, a surface surrounding the recess, which serves as a contact surface for the surface of an implant body carrying the abutment, and in the lower region a circumferential collar, the upper side of which serves as a support surface for the lower edge of the dental prosthesis element. Dental prosthesis implant according to one of the preceding claims, wherein by heating the desired shape of the mesostructure at 37 °C to a temperature in the range of 45 °C to 80 °C, a reversible deformation of the mesostructure under Increasing the recess diameter can be achieved. Dental prosthesis implant according to one of the preceding claims, wherein by heating the desired shape of the mesostructure at 37 °C to a temperature in the range from 45 °C to 80 °C, a reversible deformation of the mesostructure can be brought about with an increase in the recess diameter, the deformation brought about by heating can be maintained by cooling the mesostructure to a temperature in the range from 0 °C to 25 °C and the desired shape can be restored by heating the cooled mesostructure to 37 °C. Dental prosthesis implant according to one of the preceding claims, wherein a reversible enlargement of the recess diameter of at least 5% can be brought about by heating from 37 °C to a temperature in the range of 45 °C to 80 °C.