Description

The subject of the invention is a set of prosthetic elements comprising a fastening element and a prosthetic crown, the set having means for removing the crown without damaging it and enabling controlled cementation of the set components. The invention also relates to a method for producing a set of prosthetic elements which allows to obtain a set provided with means for removing the crown without damaging it and allowing for controlled cementation of the components of the set.

Today, the rebuilding and reconstruction of lost dentition is an important branch of dentistry. The currently used methods use sets of prosthetic elements, including prosthetic crowns, ensuring the reconstruction of lost dentition, and various types of fastening elements, which, when fastened in the jaw bone or in / on the patient's own tooth, provide an abutment on which the above-mentioned prosthetic crowns are fastened. Such a fastening element can be, for example, an intraosseous implant (implant) equipped with an implant abutment on which a prosthetic crown is fastened. In such a solution, the implant constitutes the fastening part of the fastening element, the role of which is to secure the fastening of the fastening element to the jaw bone of the patient, while the implant abutment provides the abutment for fastening element of the prosthetic crown. Another example of a fastening element is a dental post-and-core, which may be used on root canal treated teeth. Similarly to the fastening element in the form of an implant equipped with an implant abutment, the fastening element in the form of a dental post-and-core has a post, which occupies the space located in the root, acting as an fastening part of the fastening element, and the core part that replaces the tooth core and constitutes an abutment part of the fastening element, providing the abutment for fixing the prosthetic crown. Yet another example of a fastening element is a primary telescopic crown that provides an abutment for fastening a prosthetic crown (secondary crown). Telescopic crowns are a set of two crowns, where the primary crown is usually fastened on the natural teeth by means of cementation. The secondary crown (a prosthetic crown that recreates the tooth morphology or is part of a larger prosthetic work) is placed over the primary one. The secondary crown is held against the primary by frictional forces. Thus, in a telescopic crown system, the primary crown is a fastening element in which the fastening part is a cavity in the primary crown adapted in shape and size to receive the patient's own tooth, allowing the fastening element to be fastened. The outer shell of the primary crown is, on the other hand, an abutment part of the fastening element, which allows the abutment of the secondary crown.

Thus, as can be seen from the above description, in a prosthetic set comprising a fastening element and a prosthetic crown, the prior art fastening elements always provide an abutment part, or an abutment on which the prosthetic crown is placed, and fastening part ensuring the fastening of the fastening element in the bone or in / on the patient's own tooth. The fastening part of the fastening element is provided with a fastening means, which may be e.g. a thread provided on the surface of the fastening part of the fastening element (such as e.g. a thread on the outer surface of the implant), a fastening cavity that encloses the core of the tooth and allows the fastening of the fastening element with cement (e.g. in the primary crown), or a pin inserted into an endodontically treated tooth root (e.g. in a dental post-and-core).

Among the methods of fastening a prosthetic crown on the abutment part of the fastening element (hereinafter also referred to as the abutment), several types of solutions are generally distinguished, among which the most common applications are: fastening the prosthetic crown on the abutment by cementing it or screwing the pre-prepared abutment-crown complex to the implant.

Crowns attached to the abutment using dental cement have many advantages over screw-on crowns. On the one hand, the advantage of cemented crowns is that there is no need to prepare a keyhole, which is made in the aesthetic part of the prosthetic work. This contributes to a better perception of the aesthetics of implants with the cemented crown. At the same time, apart from the aesthetic value, the lack of need to make a hole on the occlusal surface of the cement- fastened crown ensures better control of occlusion, i.e. points of contact with the opposing tooth. On the other hand, crowns fastened with dental cement have a more uniform structure and are more durable. The use of dental cement as a means of fixing the crown on the abutment of the fastening element intraorally also allows the use of the phenomenon of passivation of work in the patient's mouth: the cement acts as a buffer compensating for inaccuracies in the alignment of the prosthetic work, caused by errors arising during the taking of impressions, their transport, casting models, fabrication of the prosthetic work, thermal expansion of materials, volume changes when bonding materials, etc.

There are, however, disadvantages to fastening a crown to an abutment with dental cement. Contrary to screw-on crowns, which are easy to remove from the abutment by simply unscrewing the fastening screw, in the case of crowns fastened with cement, the removal of the crown most often ends with its damage and the need to make a new crown.

The need to use cement in the patient's mouth is in itself a risk factor, so the process of fastening a crown with cement requires from a specialist a great deal of experience and skills to ensure that the amount of cement used is not excessive and that the cement is not pressed into the tissues, which can lead to inflammation of the surrounding tissues.

Methods of removing crowns fastened e.g. on an implant abutment with the aid of dental cement are known in the art. Thus, it is known to use various types of claws that allow grasping the crown and exert a pulling force along the axis of the abutment, and also tools designed to ensure a non-destructive effect (e.g. tongs provided with silicone surfaces of the working parts) are known. Often working with such tools is assisted by the use of talcum powder to increase friction. However, the non-destructive effectiveness of such methods is not high, and the crown may be damaged if the operator is inexperienced. Above all, however, the very effectiveness of these methods is low and most often attempts to remove the crown with these methods fail.

There are also semi-destructive methods, which consist in drilling recesses in the crown that enable grasping the crown with claw with sharp parts. However, these methods do not ensure the integrity of the crown after removal and often damage it as well.

Yet another method involves drilling through the occlusal wall of the crown to access the screw in the implant abutment. Also this method does not ensure the integrity of the crown after it is removed, and in addition, the correct determination of the correct drilling location is at best very difficult, or requires additional supportive methods such as the use of prefabricated matrices, photographic methods or special tools provided for this purpose.

The completely non-destructive method of removing the crown is ensured by the use of special resins, such as Richwil resin (Almore International). However, the use of such resins requires the presence of healthy opposing teeth, and moreover, it is limited to temporary cemented crowns and is effective only for selected solid cements or works already partially decemented.

As can be seen from the above, while the very problem of removing crowns fixed with dental cement is solved in the prior art by more or less destructive methods or tools, it is still problematic to fasten the crown in a way that allows control over the amount of cement used for fastening. There is therefore a need to provide a set of prosthetic elements, including a fastening element and a prosthetic crown, which will provide a method of joining the crown to the abutment part of the fastening element, in which the prosthetic crown can be secured to the abutment by means of dental cement, wherein the set would provide for a system for both enabling control of the amount of cement used to fasten the crown on the implant abutment, as well as an easy and non-destructive removal of the crown using basic dental tools.

The object of the invention is therefore to develop such a solution that allows to limit the drawbacks of the solutions known from the state of the art. This aim was achieved by a set of prosthetic elements and a method of their production, which are defined by the contents of the independent claims contained herein. The dependent claims define preferred variants of the solutions according to the invention.

The subject of the invention is a set of prosthetic elements including a fastening element and a prosthetic crown, said fastening element having an abutment part on which the said prosthetic crown is placed, and a fastening part equipped with a fastening means intended to fasten the fastening element in the bone or in / on the patient's own tooth, said crown having an occlusal wall and circumferentially connected peripheral side wall, said crown walls defining a cavity that allows the crown to be mounted on the abutment part of the fastening element, and according to the invention said assembly is characterized in that in the peripheral side wall the prosthetic crown has a through opening for receiving a crown removal tool, wherein the wall of said opening is a first abutment surface, and wherein a second abutment surface for said tool is provided in the abutment part of the fastening element, wherein said second abutment surface once the crown is embedded on the abutment part of the fastening element, is positioned in a lumen of a through opening in the circumferential wall of the crown in such a way, that a through gap is formed between the first and second abutment surfaces and the first abutment surface is nearer said occlusal wall of the crown than the second abutment surface.

In a preferred embodiment of the set of prosthetic elements according to the invention, said through opening in the prosthetic crown is in the form of a through-cut in the peripheral side wall of the crown, preferably said cut is an inverted U-shaped cut.

In a further preferred embodiment of the set according to the invention, said through opening is in the form of a through orifice, preferably a round orifice.

Preferably also, in the set according to the invention, said second abutment surface is a wall of an opening provided in the abutment part of the fastening element. In a preferred variant of the set of prosthetic elements according to the invention, said opening in the abutment part of the fastening element is in the form of a cut in the abutment part, preferably a U-shaped cut.

Preferably also, said opening in the abutment part of the fastening element is in the form of an orifice, preferably a circular opening.

Preferably also, said opening in the abutment part of the fastening element is a through opening.

Preferably, in the set according to the invention the fastening part of the fastening element is an intraosseous implant and the abutment part is an intraosseous implant abutment connected to the endosseous implant.

Preferably, in the set according to the invention, the fastening part of the fastening element comprises at least one pin of the dental post-and-core, and the abutment part of the fastening element is the crown part of the dental post-and-core.

Preferably, the set according to the invention is a set of telescopic crowns in which the fastening element is a primary crown and the prosthetic crown is a secondary crown.

The invention also relates to a method of manufacturing a set of prosthetic elements, comprising the step of providing a fastening element and a prosthetic crown, said fastening element having an abutment part on which said prosthetic crown is embedded, and fastening part provided with a fastening means for securing the fastening element to the bone or on the patient's own tooth, said crown having an occlusal wall and a circumferentially thereto connected peripheral side wall, said crown walls defining a cavity allowing a crown to be mounted on the abutment part of the fastening element, the method according to the invention being characterized in that the method according to the invention additionally includes the step of providing the prosthetic crown with a through opening in the peripheral side wall, which through opening is intended to accommodate the tool for removing the crown, and its wall is the first abutment surface for said tool, and the step in which the abutment part of the fastening element is provided with a second abutment surface for said tool, said second abutment surface being provided such that, after the crown is embedded on the abutment part of the fastening element, the second abutment surface is positioned in the lumen of the through opening in the circumferential wall of the crown such that a through gap is formed between the first and second abutment surfaces, and the first abutment surface is nearer said occlusal wall of the crown than the second abutment surface. In a preferred embodiment of the method according to the invention, said through-opening in the prosthetic crown is made in the form of a through cut in the peripheral side wall of the crown, preferably an inverted U-shaped cut.

In a further advantageous embodiment of the method according to the invention, said through opening is provided in the form of a through orifice, preferably a round orifice.

Preferably also, in the method according to the invention, said second abutment surface is provided by the wall of the opening in the abutment part of the fastening element.

In a further advantageous embodiment of the method according to the invention, said opening in the abutment part of the fastening element is provided as a cut in the abutment part, preferably a U-shaped cut.

Preferably also in the method according to the invention, said opening in the abutment part of the fastening element is provided in the form of an orifice, preferably a circular orifice.

Preferably also in the method according to the invention, said opening in the abutment part of the fastening element is provided as a through opening.

Preferably, in the method according to the invention, the abutment part of the fastening element is provided as an intraosseous implant, and the abutment part is an implant abutment of the endosseous implant connected to the endosseous implant.

Preferably, in the method according to the invention, the abutment part of the fastening element is formed as at least one pin of the dental post-and-core, and the abutment part of the fastening element is the crown portion of the dental post-and-core.

Preferably, in the method according to the invention, the set of prosthetic elements is provided as a set of telescopic crowns in which the fastening element is a primary crown and the prosthetic crown is a secondary crown.

The set of prosthetic elements according to the invention comprises a fastening element and a prosthetic crown.

Within the meaning of the invention, a prosthetic crown is a prosthetic element that rebuilds a single tooth crown. A prosthetic crown is mounted on the abutment part of the fastening element, and the crown may be fastened using dental cement. A prosthetic crown can also be a secondary crown in a set of telescopic crowns, but also an element of a prosthetic bridge or a fastened cemented prosthesis. A prosthetic crown as such is known in the art and is made of an occlusive wall that passes into a peripheral side wall, which is connected with the occlusal wall along its entire periphery. In other words, the occlusal wall extends all along its circumference into a peripheral side wall, forming a crown which is hollow and open on the side opposite the occlusal wall. The occlusal wall and the peripheral side wall thus define a cavity that is adapted in shape and size to the shape and size of the abutment part of the fastening element, allowing the crown to be embedded on the abutment, such that when the crown is secured, its peripheral side wall surrounds the abutment portion of the fastening element. The outer surface of the occlusal wall provides the occlusal surface of the reconstructed tooth crown.

Within the meaning of the invention, a fastening element is a prosthetic element, the task of which is, on the one hand, to provide an abutment on which the prosthetic crown is fastened and, on the other hand, to secure the fastening element to the bone of patient's jaw or own tooth. In this way, a set of prosthetic elements, a crown - a fastening element, ensures the reconstruction of the lost tooth.

As follows from the above, a fixing element within the meaning of the invention always has an abutment part that provides an abutment on which a prosthetic crown is placed and a part that fastens the fastening element in the bone or in or on the patient's own tooth. In this description, the terms abutment part and abutment are used interchangeably to denote the same part of the fastening element serving to receive the prosthetic crown.

Due to the function that the fastening element parts perform in the assembly according to the invention, the fastening part and the abutment part of the fastening element are on opposite sides when viewed along the longitudinal axis of the fastening element. Thus, on one side of the fastening element (provided towards the patient's jaw) there is a fastening part of the fastening element, which is provided with a fastening means, which can be e.g. a thread provided on the surface of the fastening part of the fastening element (such as an external thread on an implant), fastening recess covering the core of the own tooth (as in the primary crown), or a dental post inserted into the endodontically treated tooth root (as in the dental post-and- core). On the other side of the fastening element (provided away from the patient's jaw) there is an abutment part, or abutment, of the fastening element.

The prosthetic crown is placed on the abutment in the target position and the crown is also cemented in this position. A prosthetic margin can be provided in the abutment part of the fastening element whereby, in such an embodiment, in said target position, the peripheral side wall of the prosthetic crown rests on the prosthetic margin of the fastening element. In this position, i.e. in the position where the peripheral side wall of the crown contacts the prosthetic margin provided in the fastening element, the prosthetic crown is fastened with dental cement to the abutment part of the fastening element.

According to the invention, a through opening is provided in the peripheral side wall of the crown, said opening being most preferably provided such that after the prosthetic crown is embedded on the fastening element attached to the patient's bone / tooth, the through opening is accessible from the lingual or palatal side. Said through-opening is provided in the peripheral side wall of the crown in such a way that the axis along which said opening extends inwardly to the crown is substantially perpendicular to the longitudinal axis of the fastening element, i.e. the axis along which the fastening element extends from the abutment part towards the fastening part (i.e. in the direction towards the patient's jaw).

The through-opening in the peripheral side wall of the prosthetic crown is intended to accommodate the tool for removing the crown. The wall of said through-opening closest to the occlusal wall of the crown provides a first abutment surface for said tool. The second abutment surface for said tool in the set of prosthetic elements according to the invention in one embodiment is provided by the front surface of the abutment part of the fastening element, i.e. a surface substantially perpendicular to the longitudinal axis of the fastening element and which, when the crown is secured to the abutment part, faces the occlusal wall of the crown. In such a preferred embodiment, the prosthetic crown is placed on the abutment of the fastening element in such a way that there is a free space between the front surface of the abutment and the inner surface of the occlusal wall of the crown. This can be achieved, for example, by providing a prosthetic step on the abutment on which the embedded crown rests in such a way that its occlusal wall, after embedding the crown, remains at a distance from the front surface of the abutment. It can also be envisaged that the outer perimeter of the abutment increases along its extent in the direction opposite to the abutment front surface (in the direction towards the patient's jaw), so as to provide a prosthetic step at a certain height of the abutment, i.e. a place where it will no longer be possible to place the crown will any further on the abutment, providing some free space between the front surface of the abutment and the inner surface of the occlusal wall of the crown. At the same time, in such a preferred embodiment, said through- opening in the peripheral side wall of the prosthetic crown is provided so that the said front surface of the abutment part of the fastening element, after the crown is secured, apears in the lumen of the through opening and at the same time so that between said front surface of the abutment part of the prosthetic element a gap is formed between the side wall of the crown and the wall of said opening. This gap interconnects the through opening in the crown with the free space between the front surface of the abutment and the inner surface of the occlusal wall of the crown, thus providing a place for receiving the tool to be inserted between the two abutment surfaces thus formed. Such a tool can be any tool with a pin-shaped working part having an increasing diameter (e.g. a dental probe), wherein the diameter of the tip of the tool that slides in between said abutment surfaces is smaller than the distance between said abutment surfaces and gradually increases along the extention of the tool until it reaches a diameter which is greater than the distance between said abutting surfaces, so that further insertion of the tool in between subjects the edges of the abutting surfaces to forces directed substantially parallel to the longitudinal axis of the fastening element. Upon action of said forces, the implant crown attached to the abutment gets disconnected. Such an action of the tool, i.e. an action applied only in the direction substantially perpendicular to the longitudinal axis of the fastening element, is an optimal action as it works only within the limits of the through opening in the crown, without causing additional stress in the crown, which could for example be caused by swinging movements of the tool, i.e. up-down movements in the longitudinal direction of the fastening element. Such an operation of the tool should be avoided. Due to the mutual relation of the retaining surfaces, removal of the crown can be achieved by simply inserting the tool between the retaining surfaces and further into the lumen of the gap formed therebetween. Such an impact of the tool on the elements of the set ensures non-destructive removal of the crown without the necessity to "pry" it, which is always associated with the risk of damaging the crown. Thus, the solution according to the invention provides optimal conditions for the removal of the crown, without the risk of damaging its outer coating, i.e. its veneering.

In said advantageous embodiment of the solution, said through-opening in the circumferential side wall of the crown is provided at such a distance from said occlusal side of the crown that after the crown has been mounted on the abutment of the fastening element, the edge of the described front surface of the fastening element is located in the crown in the lumen of the opening, which ensures meeting of the condition wherein the first abutment surface (formed by the opening wall of the crown) is nearer the occlusal wall of the crown than the second abutment surface formed by the front face of the fastening element. Preferably, the location of the opening in the peripheral side wall of the crown is provided such that, after the crown is secured to the abutment, the distance between the abutment surfaces allows the use of standard dental tools as a crown removal tool. Within the meaning of the invention, the condition that the first abutment surface is nearer the occlusal wall of the crown than the second abutment surface means in other words that the distance between the point of intersection of the longitudinal axis of the fastening element with the second abutment surface and the point of intersection of said axis with the outer surface of the occlusal wall is greater than the distance between the point of intersection of the longitudinal axis of the fastening element with the first abutment surface and the intersection of said axis with the outer surface of the occlusal wall. The outer surface of the occlusal wall here means the occlusal surface of the crown that is intended to come into contact with the opposing tooth.

In a preferred embodiment of the invention, the opening in the peripheral side wall of the crown is in the form of an orifice, the orifice preferably being circular. It is clear to the person skilled in the art that said orifice may also be oval or have a different shape derived from the method of making it.

In another, advantageous embodiment of the invention, the opening in the peripheral side wall of the crown may have the form of a through cut in the peripheral side wall, whereby a through cut in the circumferential side wall is to be understood as clearance the crown wall which is open on the edge side of the wall opposite to the occlusal wall (i.e. open in the direction towards the patient's jaw). In other words, said cut extends from the edge of the peripheral side wall opposite the occlusal side (where said cut is open) towards the occlusal wall where the cut closes to form the cut wall that provides the first abutment surface. The cut preferably may be in the shape of an inverted U, i.e. a cut, the sides of which extend substantially parallel to the longitudinal axis of the fastening element and meet in the form of an arc thus creating a cut wall providing a first abutment surface. It is clear to one skilled in the art that also other shapes of the cut can provide a suitable wall to form the first abutment surface.

In a further advantageous embodiment, the second abutment surface is formed by a wall of a preferably through opening provided in the abutment part of the fastening element. In a preferred embodiment of the invention, said opening is in the form of a circular, preferably through orifice. It is clear to the person skilled in the art that said orifice may also be oval or otherwise shaped as long as, after the crown is secured to the abutment, the opening in the wall of the abutment is in the lumen of an opening in the peripheral side wall of the crown, providing a second abutment surface as well as providing a thought gap for inserting a tool.

In another advantageous embodiment of the invention, the opening in the abutment part of the fastening element may be in the form of a through-cut in the abutment part, where a through- cut is meant as a through clearance in the abutment part which is open on the side of said front surface of the abutment part (i.e. open on the side opposite to the patient's jaw). In other words, said cut in the abutment part extends from said front surface of the abutment port (wherein said cut is open) towards the fastening part, where the cut closes to form a cut wall that provides a second abutment surface. The cut preferably may be U-shaped, i.e. a cut the sides of which extend from the front surface substantially parallel to the longitudinal axis of the fastening element and meet in the form of an arc to form a wall thus creating a cut wall providing a second abutment surface. It is clear to one skilled in the art that also other shapes of the cut can provide a suitable wall for forming the second abutment surface.

In a further advantageous embodiment of the invention, a channel is provided in the abutment part of the fastening element which is open on the side of said abutment front surface and which channel extends towards the fastening part along the longitudinal axis of the fastening element. In such a preferred embodiment, the gap formed between the first and second abutment surfaces connects the opening in the prosthetic crown with the channel provided in the abutment part of the fastening element. In such a preferred embodiment, the tool inserted between the first and second abutment surfaces may be pushed deeper into the space of the channel formed in the abutment until the bond of the connecting cement is broken and the crown detaches. In such a preferred embodiment, said opening in the abutment part of the fastening element is provided in such a location that, after the crown is fastened to the abutment, the above-described opening wall in the abutment part is visible in the lumen of the opening in the crown (its edge is thus visible in the lumen of the opening in the crown), while at the same time the condition is met whereby the first abutment surface (formed by the wall of the opening in the crown) is nearer the occlusal wall of the crown than the second abutment surface formed by the wall of the opening in the abutment part of the fastening element. Preferably, the location of the opening in the peripheral side wall of the crown is provided such that the distance between the formed abutment surfaces allows the use of standard dental tools as a crown removal tool.

An embodiment of the set of prosthetic elements according to the invention which is particularly advantageous and the easiest to implement, is one in which the through opening in the peripheral side wall of the crown and the opening, preferably through, in the abutment part of the fastening element are both in the form of round orifices, preferably of the same diameter. It should be noted here that said orifices may have a constant diameter over the entire extent of the through opening, but it is also possible to materialize that the diameter of said through orifices decreases along the extent of the orifices in the direction from the peripheral wall of the crown towards the longitudinal axis of the abutment. In such an embodiment of the solution, the swinging movement of the tool is also allowed in order to introduce additional forces acting on the abutment surfaces. The axially converging openings provide space for a collision-free pendulum movement of the tool, without disturbing the arrangement of the abutment surfaces provided for the tool.

The opening in the abutment part of the fastening element can most preferably be provided in the form of a through opening, i.e. an opening providing a through clearance in a direction perpendicular to the longitudinal axis of the fastening element. In the case of such an advantageous embodiment, such a through opening can be provided over the entire width of the abutment part of the fastening element, whereby the width of the abutment part is understood here to mean the dimension of the abutment along the axis perpendicular to the longitudinal axis of the fastening element. In an embodiment of the invention in which the above-described channel is provided in the abutment part and extending along its longitudinal axis towards the fastening part of the fastening element, the opening in the abutment part is provided as an opening connecting with said channel, i.e. extending along an axis perpendicular to the longitudinal axis of the fastening element and extending into said channel. In such a variant, the through clearance formed between the first (in the crown) and the second (in the abutment) abutment surfaces will extend into said channel, providing space for the tool to be inserted between the abutment surfaces and further inside the channel. However, it is clear to a person skilled in the art that the opening in the abutment does not have to be a through opening, as long as its depth (dimension along the opening axis) provides the length of the gap between the abutment surfaces allowing the tool to be inserted deep enough as to ensure removal of the crown.

The solution according to the invention provides a simple method of removing a crown fastened with a cement on the implant abutment. After the set is attached, the opening in the crown can be closed in a known manner i.e. with the composite material, according to the procedure commonly used for closing the opening in a screwed-on crowns. If necessary, the removal of the composite material is carried out by conventional methods without damaging the crown. At the same time, due to the fact that a clearance is created between the abutment surfaces provided in the prosthetic elements of the set according to the invention, which clearance connects the opening in the crown with the hollow space formed between the occlusal wall of the crown and the front surface of the abutment, and in a preferred variant also additionally with the abovementioned channel provided in the abutment during cementation of the crown, it is ensured that at least a portion of the cement excess drains through the above-mentioned clearance, thus limiting cement introduction into the surrounding tissues.

The solution according to the invention also relates to a method of producing a set of prosthetic elements comprising providing prior art prosthetic elements (i.e. fastening element and prosthetic crown) and providing said elements with means according to the invention for removing the crown without damaging it and allowing controlled cementation of the set components. Said means in the method according to the invention are provided by a method step in which a through opening is made in the peripheral side wall of the prosthetic crown, which through opening is intended to receive the crown removal tool w its wall provides a first abutment surface for said tool. In a second step of the method according to the invention, a second abutment surface for said tool is provided in the abutment part of the fastening element, said second abutment surface being provided such that, after the crown is embedded on the abutment part of the fastening element, the second abutment surface is located in the lumen of the through opening in the peripheral side wall of the crown such that a through gap is formed between the first and second abutment surfaces. The two steps are performed in such a way as to cause that the first abutment surface that is provided by the opening in the crown is nearer said occlusal wall of the crown than the second abutment surface that is provided in the abutment portion of the fastening element. The performance of both steps can be envisaged in a manner known in the art, i.e. by drilling an opening in the peripheral side wall of the crown at a suitable height with respect to the second abutment surface provided in the abutment, for example. It is clear to the person skilled in the art that the sequence of steps in the method may be arbitrary, i.e. it may first be envisaged to provide a second abutment surface in the abutment part (e.g. by laser cutting, drilling etc.), and then the opening position in the peripheral wall of the crown can be adjusted accordingly so that a through gap is formed between the first and second abutment surfaces, and the first abutment surface is nearer the occlusal wall of the crown than the second abutment surface. It is also possible to first make an opening in the crown by providing a first abutment surface and then in a next step provide a second abutment surface. In the era of digital techniques, it is also possible to design both elements in a virtual environment and manufacture them as ready in a known manner using CAD / CAM methods.

Further features and advantages of the invention will become more apparent from the following description of the preferred embodiments, which are presented for illustrative purposes only and do not in any way limit the scope of protection defined by the appended claims. The set of prosthetic elements according to the invention is shown in the exemplary embodiments based on the drawing, in which:

Fig. l is a schematic cross-section schematic view of the set of prosthetic elements comprising the fastening element and the prosthetic crown in a first embodiment.

Fig. 2 is a schematic cross-section view of the set of prosthetic elements including the fastening element and prosthetic crown in a second embodiment

Fig. 3 is a schematic cross-section schematic view of the set of prosthetic elements comprising the fastening element and the prosthetic crown in a third embodiment.

Fig. 4 is the set of prosthetic elements according to the first embodiment as viewed from the side of the opening in the peripheral side wall of the crown.

Fig. 5 is the set of prosthetic elements according to the second as viewed from the side of the opening in the peripheral side wall of the crown.

Fig. 6 is the set of prosthetic elements according to the fourth embodiment as viewed from the side of the opening in the peripheral side wall of the crown.

Fig. 7 is the set of prosthetic elements according to the fifth embodiment as viewed from the side of the opening in the peripheral side wall of the crown.

Fig. 8 is the set of prosthetic elements according to the sixth embodiment as viewed from the side of the opening in the peripheral side wall of the crown.

Figures 9 and 10 schematically show steps of crown removal by insertion of the tool between the first and second abutment surfaces.

Fig. 11 schematically illustrates the discharge of cement excess through the gap formed between the first and second abutment surfaces.

In the above drawing figures, similar reference numerals refer to similar elements.

The set of prosthetic elements 1 according to the invention in the embodiment shown in Fig. 1 has a fastening element 2 and a prosthetic crown 3, said fastening element having an abutment part 2', on which said crown 3 is embedded, and an fastening part 2" provided with a fastening means 4. The prosthetic crown 3 has an occlusive wall 5 and a circumferentially connected side wall 6, in which there is a through opening 7, the wall of which forms the first abutment surface 8, while the top surface of the abutment portion 2' forms the second abutment surface 9, and a through gap 10 is provided between the first 8 and second 9 abutment surfaces.

The fastening means 4 in the fastening part 2" of the fastening element 2 in the embodiment of the set 1 according to the invention shown in Fig. 1 is provided as a thread formed on the surface of the fastening part 2", which enables the fastening element 2 to be fastened to the patient's bone (not shown).

The through-opening 7 in the peripheral side wall 6 of the crown 3 is intended to receive the crown removal tool, whereby the through opening 7 transforms into the through gap 10 between the first abutment surface 8 and the second abutment surface 9, allowing the tool to be inserted through opening 7 at said through gap 10 (not shown).

In the embodiment shown in Fig. 1, a through opening 7 is provided in the peripheral side wall 6 of the crown 3 in such a way that the axis X along which said opening extends inwards to the crown is perpendicular to the longitudinal axis Y of the fastening element 2, i.e. an axis along which the fastening element extends from the abutment part 2' towards the fastening part 2" (i.e. in a direction towards the patient's jaw).

As shown in Fig. 1, the prosthetic crown 3 is embedded on the abutment part 2' of the fastening element 2 in such a way that a free space remains between the front surface of the abutment part 2', i.e. the surface opposite the occlusal wall 5 forming in this embodiment the second abutment surface 9, and said occlusal wall 5 of crown 3, forming in this embodiment said gap 10.

In the embodiment of the invention schematically shown in Fig. 1, the through gap 10 can be obtained by providing a prosthetic step 13 on the fastening part 2" so that by adjusting the size of the crown and the position of the through opening 7 in the peripheral wall 6 of the crown 2, when the crown is embedded it rests on the prosthetic step 13 so that its occlusal wall remains at a distance from the front surface of the abutment which in this embodiment provides the abutment surface 9.

The through opening in the peripheral side wall of the prosthetic crown is intended to accommodate the tool for removing the crown. The wall of said through opening 7 closest to the occlusal wall of the crown provides a first abutment surface 8 for said tool.

As can be seen in Fig. 1 (and better in the view of the set according to this embodiment shown from the side of the opening 7 as shown in Fig. 4), once the crown 3 is embedded on the abutment part 2' of the fastening element 2, the second abutment surface 9 is positioned in the lumen of the through opening 7, which means that through the opening 7 available is the gap 10, formed between the first 8 and second 9 abutment surfaces, and wherein, as can be seen in Fig. 1, the first abutment surface 8 is nearer the occlusal wall 5 of the crown 3 than the second abutment surface 9. The condition that the first abutment surface 8 is nearer the occlusal wall 5 of the crown 3 than the second abutment surface 9 means in other words that the distance between the Y axis intersection with the second abutment surface 9 and the Y axis intersection with the outer occlusal wall 5 surface is greater than the distance between the Y axis intersection with the first abutment surface 8 and the Y axis intersection with the outer surface occlusal wall 5. The outer surface of the occlusal wall here means the occlusal surface of the crown intended for contact with the opposing tooth.

In the embodiment of the set according to the invention shown in Fig. 1, the fastening element has two separate parts, i.e. an abutment part 2', which functions as an abutment on which the prosthetic crown 3 is placed, and a fastening part 2", whose role is to secure the entire fastening element to the patient's bone or own tooth. As shown in Fig. 1, the abutment 2' is fastened in the fastening part 2" by means of a clamping bolt 12 embedded in a channel 11 provided in the abutment 2' and, respectively, in a channel 12' provided with a thread allowing the fastening screw 12 to be screwed in, which connects the abutment part with the fastening part, thus forming a complete fastening element 2. Fastening elements of this type, such as the one schematically shown in Fig. 1, are known in the art as prosthetic elements comprising the combination of a intraosseous implant and an implant abutment. The known in the prior art, an intraosseous implant may in the set according to the invention act as an fastening part of a fastening set, while the implant abutment may function as an abutment part of a fastening element. Both can be joined together by bolt or friction. In the prior art, there are also known one-piece implants in which the intraosseous implant and the abutment form one integral whole, and such one-piece implants also exemplify the fastening element according to the invention.

Fig. 2 schematically shows a preferred embodiment of a set of prosthetic elements according to the invention, in which the second abutment surface 9 is provided by a wall of a through opening 14 provided in the abutment part 2', such that a through gap 10 is formed between the abutment surfaces 9 and 8 connecting said through opening 14 with channel 11.

As shown in Fig. 2, as in the embodiment shown in Fig. 1, the first abutment surface 8 is closer to the occlusal wall 5 of the prosthetic crown 3 than the second abutment surface 9 which is farther away from said occlusal wall 5. Fig. 3 shows schematically a preferred embodiment of a set of prosthetic elements according to the invention, in which the second abutment surface 9 is provided by a wall of a through opening 14 provided in the abutment part 2', the through opening 14 being provided over the entire extent along the axis X, perpendicular to the longitudinal axis Y the fastening element. In this variant of the solution, the through gap 10 is provided by a through opening 14 connecting with a through opening 7 in the circumferential side wall 6 of the prosthetic crown.

Fig. 4 shows schematically in a view from side of the opening in the peripheral side wall the embodiment of the solution shown in Fig. 1. In the lumen of the through opening 7 there is a front surface of the abutment part 2' (indicated by a dashed line), which forms the second abutment surface 9. The drawing shows that the first abutment surface 8 is closer to the occlusal wall 5 of the crown 3 than the second abutment surface 9, which is further away from the said occlusal wall 5. In the embodiment shown, the through opening 7 is provided in the form of a circular orifice.

Fig. 5 shows schematically a view from the side of the opening in the peripheral side wall in the embodiment shown in Fig. 2. In the lumen of the through opening 7 there is a wall of the through opening 14 forming a second abutment surface 9. It is shown in the drawing that the first abutment surface 8 is closer to the occlusal wall 5 of the crown 3 than the second abutment surface 9, which is further away from said occlusal side 5. A through gap 10 is formed between the abutment surfaces 8 and 9 and it connects said through opening in the circumferential wall of the crown with the implant abutment channel 11 provided in of the abutment part 2' (marked with a dashed line). In this embodiment, both openings 7 and 14 are in the form of a circular orifice.

Fig. 6 shows schematically a preferred embodiment in which the opening 7 is in the form of a cut (i.e. a circumferentially open clearance) which is open at one end where the crown 3 adjoins the prosthetic step 13 while on opposite end the cut is closed to form a cut wall which provides the first abutment surface 8. In other words, the cutout shown in the embodiment in Fig. 6 has an inverted U shape, i.e. a cut whose sides run parallel to the longitudinal axis Y of the implant and meet in the arc-wise fashion to to form a wall of the cut which provides for the first abutment surface 8. It will be clear to one skilled in the art that also other shapes of the cut can provide a suitable wall to form the first abutment surface. In this preferred embodiment, the second abutment surface 9 is provided by the wall of a circular through opening 14 provided in the abutment part 2' (marked by dashed lines). As shown in Fig. 6, it can be seen that the first abutment surface 8 is closer to the occlusal wall 5 of the crown 3 than the second abutment surface 9, which is farther away from said occlusal wall 5. Between the abutment surfaces 8 and 9, a through gap 10 is formed that connects said through cut 7 in the peripheral wall of the crown with a channel 11 (marked with a dashed line).

Fig. 7 shows schematically a variant of the solution in which the through opening 7 in the peripheral wall 6 of the crown 3 has the form of a round orifice, and the opening 14 is analogous to that shown in Fig. 6, except that in the example of the solution shown in Fig. 6, the cut has the shape of an inverted U-cut, but in the variant shown in Fig. 7, the through opening 14 is a U-shaped cut, wherein the arc-shaped part of the cut which is in the lumen of the through opening 7 in the crown 3 provides for a wall forming the second abutment surface 9. It is also seen in Fig. 7 that the first abutment surface 8 is closer to the occlusal wall 5 of the crown 3 than the second abutment surface 9 which is farther away from said occlusal wall 5. A passage is formed between the abutment surfaces 8 and 9 through gap 10 which connects said through opening 7 in the peropheral wall of the crown with the channel 11 provided in the abutment part 2' (marked with a dashed line).

Fig. 8 shows schematically an embodiment in which the through opening 7 is realized as an inverted U-cut, and the through opening 14 is implemented as a U-shaped cut (partly indicated by a dashed line). Analogously to the previous embodiments, also in Fig. 7 it can be seen that the first abutment surface 8 is closer to the occlusal wall 5 of the crown 3 than the second abutment surface 9, which is farther away from said occlusal wall 5. Between the abutment surfaces 8 and 9, there is a through gap 10 connecting said through opening 5 in the peripheral wall of the crown with the channel 11 of the abutment part 2' (marked with a dashed line).

Figures 9 and 10 schematically show how to remove a crown by inserting a tool between the abutment surfaces. In the exemplary embodiment shown, a through opening 7 is provided in the peripheral side wall of the prosthetic crown so that the second abutment surface 9, after embedding the crown, is in the lumen of the through opening, and that a through gap 10 is created between the abutment surface 8 and the abutment surface 9. This gap connects opening in the crown with the channel 11, thus providing a place to receive the tool 16 to be inserted between said two abutment surfaces. Such a tool can be any tool with a pin-shaped working part having an increasing diameter (e.g. a dental probe), wherein the diameter of the tip of the tool that is inserted between said abutment surfaces (Fig. 9) is smaller than the distance between said abutment surfaces and gradually increases along the extension of the tool until it reaches a diameter greater than the distance between the abutment surfaces, so that further insertion of the tool between the abutment surfaces causes the edges of said abutment surfaces to be subjected to forces substantially parallel to the longitudinal axis of the fastening element. Under the influence of the above-mentioned forces, the implant crown attached to the abutment gets disconnected (Fig. 10).

Figure 11 schematically shows the discharge of cement excess through the clearance formed between the first 8 and second 9 abutment surfaces.

The set of prosthetic elements according to the invention is used in a manner known in the art, which will now be illustrated by an example of a set in which the abutment part of the fastening element is an implant abutment and the fastening part is an implant (intraosseous implant), as schematically shown in Fig. 11. In such an exemplary set, the abutment is screwed onto the implant embedded in the patient's bone, and then an appropriate amount of cement is spread over the inner surface of the crown (i.e., in a cavity defined by the peripheral sidewall and occlusive wall of the crown). Then the crown is placed on the abutment into its final position, i.e. the position where the crown rests on the prosthetic step. The increasing pressure inside the abutment-crown system causes cement excess to escape to the outside (as schematically shown in Fig. 11 by arrows). Traditionally, the main escape route for cement is a dangerous direction deep into the patient's tissues, often resulting in complications. However, in the solution according to the invention, thanks to the through openings in the abutment and the crown, creating a through gap 10 connecting the opening in the crown with the space between the crown and the abutment, there is a valve effect - the cement has an additional, safe exit route to the outside of the abutment-crown system and to the possible channel for the screw fastening the abutment.

Therefore, the solution according to the invention allows to significantly reduce the risk of periimplant cementitis (inflammation of the tissues around the implant caused by an excess of prosthetic cement).

Although the above advantageous operation of the set of elements according to the invention is described in the preferred examples in which the fastening element comprises an implant abutment serving as an abutment part and a medial implant that functions as a fastening part, it is clear to a person skilled in the art that the solution according to the invention can be used within the scope of the following claims also in other known sets including, for example, one- piece implants, a telescopic crown system or a dental post, core and crown.