The object of the invention is a fixed partial denture according to the preamble to claim 1. According to traditional methods, one or two teeth extracted from between teeth can be replaced with different types of fixed partial dentures, which are attached to support pillars ground into the abutment teeth adjacent to the opening. Thereby, based on impressions, the dental technician makes a metal-framed bridge. The manufacturing costs of the bridge and many treatment visits make the solution expensive. Alternatively, a dental technician or dentist can also use plastic, composite plastic or some hard substance to make a bridge. In this instance usually only a groove is ground into the abutment teeth biting surface for attaching the bridge’s pontic. Treatment costs are relatively expensive due to many work stages. Publications US2005/0037321A1, US2019/0247150A1, US2019/0175307A1 , US4,556,388 and WO00/40170A1 have presented known solutions. In some solutions, it is a known solution to use for attaching the bridge’s pontic a connection which has a spherical part and as its counterpiece a concave hollow-like hemispherical support cup comprised of one piece. The attachment allows the anchoring part to be turned in different directions, but the attachment’s locking is based on the point-like surface pressure of the spherical part caused by a screw or the filling of the hollow’s empty space with a sealing material. In the publication WO2011/152643A2 the locking member is a screw, with which the pontic module’s parts are pressed together. At the same time, their wing parts are pressed around the abutment tooth crowns, but the direction of the wing parts cannot be changed.

In several known fixed partial denture structures, implants anchored in the jawbone have been used, which cannot be made ready during one dentist visit, even when combined with other structures. Known structures do not enable as such assembling a finished bridge structure in which the anchoring parts would be freely selectable independently of one another in terms of size, shape or attachment direction. They also do not allow the stepless adjustment of the distance between the anchoring parts. Any screw locking of the attachment joint of the fixed partial denture pontic places a large point-like stress on the spherical part, which, in use, can break the joint and the structure of the fixed partial denture. The purpose of this invention is to achieve a fixed partial denture that overcomes the above-mentioned drawbacks. The fixed partial denture according to the invention is characterised in what has been presented in the characteristics section of claim 1. A fixed partial denture according to the invention is a modular bridge that has a pontic module comprised of one or more pontics and anchoring parts to be attached to the abutment teeth. According to the invention, the grinding or recesses of the abutment teeth made in the anchoring parts do not have to be parallel to one another and at a specific distance from one another in order to get the bridge in place on the abutment teeth. According to the invention, the position of the anchoring parts to be attached to the abutment teeth can be changed independently of one another in relation to the pontic module. This is enabled by an essentially spherical part belonging to the anchoring part or the pontic, which spherical part is located in a space in the pontic module or anchoring part, which space can also be essentially spherical in shape.

The spherical part can also be, however, a polygonal piece, whose edges together form an essentially spherical piece. Also the counterpiece of the spherical part, i.e. a spherical space, in which the polygonal piece is placed, can be formed from a polygonal surface, the parts of which surface together form an essentially spherical space. The spherical part and/or its counterpiece can also be equipped with edge steps. In a structure such as this, the polygonal part can be turned like a sphere when it has been loosely placed in a space intended for it that is formed by a polygonal surface. After the spherical polygonal part is locked in the space intended for it by pressing the walls of the space formed by the polygonal surface against the polygonal part, the joint is locked efficiently.

According to the invention, the anchoring parts of the modular bridge also do not need to be first attached to the abutment teeth because the modular bridge formed by the anchoring parts and the pontic module between them can be adjusted outside the mouth to fit the space formed by one or more extracted teeth. Also enabling the adjustment of the modular bridge to fit this space is that the anchoring parts’ mutual distance from one another and distance from the pontic module can be adjusted steplessly. The modular bridge according to the invention can be adjusted to be suitably sized and shaped in all adjustment directions on the x, y and z coordinate system. In this instance, the modular bridge according to the invention can be precisely adjusted and attached also to abutment teeth that are differently orientated. Undercuts resulting from the abutment teeth’s positions and differently orientated grinding directions in them would prevent the fitting of a fixed bridge structure in its attachment position. A pontic module and/or anchoring parts according to the invention also do not have to be separately assembled, in the known manner, with the help of an impression using plaster dies or in the mouth by first connecting them to one another with tooth filling material and/or cementing material used to attach dentures.

In a modular bridge according to the invention, cavities that have mutually different shapes, sizes and directions can also be ground into the abutment teeth, which cavities are formed when softened dental tissue is removed from the abutment teeth and/or attaching grooves into which are placed the most suitable anchoring parts. The anchoring parts are attached to the abutment teeth cavities either with filling materials or adhesive or cementing materials used to attach dentures. The anchoring parts can also be cemented, i.e. attached, only to the abutment tooth surface with an attaching flange or by gluing support fibres. During the same visit, the modular bridge with its anchoring parts is cemented, i.e. attached to the abutment teeth in the correct position in place of the missing tooth. Fixing the modular bridge can be carried out simply by tightening, with a separate tool, the pontic module’s fixing device, which can be one or more screws and/or bolts, whereby the anchoring parts with their spherical parts are pressed to be immobile inside the pontic module.

According to the invention, all of the required parts can be prefabricated industrially to be of uniform quality from wear-resistant and sufficiently strong materials, which are medically approved substances. The manufacturing materials can also be mixtures or combinations thereof, which are additionally aesthetically the best fit for the mouth. These materials are, for example, ceramic materials already in use, mutually chemically curing plastics made of two soft plastics, light-curing plastics, composite plastics containing ceramic particles or fibres, different denture metal alloys or combinations thereof. The manufacture of parts using some materials can be done at a high temperature and pressure, whereby no internal stress or partially uncured ingredients remain in the pieces to be manufactured to cause an allergy even after several years. Some materials can be milled from blanks as series production or cast in large series.

The modular bridge according to the invention comprised of parts offers a solution to most missing tooth restoration problems and is essentially completely new in its solutions, structures and function. Although bridge dentures have been made previously from one or two ready-made parts to replace one or more missing teeth, it has not been previously possible, without impressions, to make, during one patient visit, bridges assembled from ready-made parts of different sizes and shapes, which bridges have anchoring parts adjustable on the x, y and z coordinate system.

In a modular bridge according to the invention, a pontic module comprised of one or more parts and its anchoring parts form the final modular bridge. What is essential for the fixed partial denture is that a modular bridge assembled from industrially manufactured parts can be permanently fixed to the abutment teeth in a suitable position for the occlusion during a single visit. The dentist does not need to make any expensive investments in equipment. A relatively small selection of parts required to assemble the modular bridges with their drill bits is sufficient. This saves the dentist and patient both time and trouble compared to other known methods. When a modular bridge is completed in one go, there is no need for dies made with impressions. In terms of cost-effectiveness, this method and bridge structure is financially excellent and industrial production is quite profitable after the initial investments.

The required work stages for installing a modular bridge according to the invention in place in a patient’s mouth are the following, for example. The modular bridge is formed outside of the patient’s mouth such that the modular bridge’s anchoring parts to be fixed to the abutment teeth are attached to a pontic module to be assembled from parts. The pontic module is assembled from parts that allow the assembled pontic module to fit into the empty space formed by a missing tooth or missing teeth.

When selecting the pontic module’s parts, for example the size and shape of the empty space formed by the missing tooth or missing teeth and the colour of the adjacent abutment teeth are taken into account. When selecting the anchoring parts, the size and shape of cavities possibly made in the adjacent abutment teeth is taken into account.

When the modular bridge has been assembled, the formed modular bridge is fitted into place in the patient’s mouth in the empty space formed by one or more missing teeth. In the fitting it is observed whether the parts selected for the modular bridge are suitable. If changes are required to the modular bridge, the parts used in it are changed as required.

The fitting into place of a modular bridge according to the invention is significantly helped by the fact that the anchoring parts to be attached to the abutment teeth in the modular bridge can be moved in relation to the pontic module at this stage. Anchoring parts can thereby be rotated in relation to the pontic module, turned in the sideways direction and/or turned vertically. According to the invention, the anchoring parts can also be moved such that the distance of the anchoring parts to one another is changed. Thereby, the anchoring parts can be rotated, turned or moved in relation to one another on an x, y and z coordinate system independently of one another. This is made possible by the joint member between the anchoring parts and pontic module being spherical. In addition, the spherical joint member can be located in an adjustment part which allows the movement of the anchoring parts’ spherical joint members towards or away from one another.

When a modular bridge according to the invention has been adjusted to fit into the empty space formed by one or more teeth, the anchoring parts of the formed modular bridge can be cemented to the adjacent abutment teeth or cavities formed in them. At this stage, a protective plastic film can be placed over the modular bridge to prevent the cement from adhering to the opposite teeth when the jaws are occluded.

When the modular bridge anchoring parts have been attached to the abutment teeth, a highly liquid adhesive or cement is fed into the spaces of the pontic module’s parts and the spherical joint members between the pontic module and anchoring parts. After that, the parts of the modular bridge can be locked into place with one or more locking members located in the pontic module. The locking members can be, for example, one or more tightening screws, which are tightened with a separate tool such that the parts of the pontic module, the parts of the adjustment members in the pontic module and the parts between the pontic module and anchoring parts are pressed against one another and locked into place to be immobile. Also at this stage, a protective plastic film can be placed over the modular bridge to prevent the cement from adhering to the opposite teeth when the jaws are occluded.

After the adhesive or cement fed into the modular bridge has cured, the modular bridge is complete with the exception of finishing. Any sharp edges, overflowed cementing material or protruding fastening screw heads possibly remaining are ground away in the finishing of the module bridge.

According to the invention, the fixed partial denture is a modular bridge installed in the place of one or more extracted teeth, in which fixed partial denture is a pontic module and anchoring parts to be connected to it that are to be attached to the adjacent abutment teeth. The pontic module of the modular bridge is formed from parts. An anchoring part to be connected to an abutment tooth has been connected to the pontic module with a joint, which allows the anchoring part to move in relation to the pontic module when the modular bridge is fitted into place between the abutment teeth. The joint between the anchoring part and pontic module can be locked to be immobile with the modular bridge locking member after the modular bridge has been put in place in a space formed by one or more extracted teeth. The joint of the modular bridge anchoring part and the pontic module can be spherical such that to the anchoring part or pontic belongs a support sphere, which rests on a spherical space belonging to the pontic module or anchoring part. The anchoring part may also have a concave, hemispherical support cup, which rests on a part in connection with the pontic module, which part is at least partly spherical. The spherical joint allows the rotating of the anchoring part in relation to the pontic module and the turning of the anchoring part sideways in any direction, whereby the anchoring parts can be made to be at the desired angle to one another when attaching the modular bridge to the adjacent abutment teeth. The spherical part and its counterpiece or counterpieces can also be polygonal, but still essentially spherical. In this instance, the polygonal part can be turned when it is not being pressed between the counterpieces. The joint is locked such that the counterpieces are pressed against the spherical or polygonal part. In connection with the modular bridge’s pontic module there can be an adjustment part with the help of which the distance of the anchoring part from the pontic module can be changed. Using the spherical joint and adjustment part, the movement of the anchoring part in relation to the pontic module is possible in all adjustment directions on an x, y and z coordinate system.

According to the invention, the pontic module has two halves, in each of which is an essentially hemispherical recess. When the halves of the pontic module are placed against one another, the hemispherical recesses together form an essentially spherical space. The support sphere belonging to the anchoring part is located inside the spherical space formed inside the pontic module’s halves. The support sphere and spherical space together form a joint, supported by which the anchoring part can be rotated and/or turned to the side in any direction.

The pontic module halves or separate corresponding compressing parts in the pontic module can be pushed against one another such that the support sphere or polygon of the anchoring part is pressed against the walls of the essentially hemispherical recesses of the pontic module halves or compressing parts. The pontic module halves can also be formed from many kinds of polygons and they can be pressed against one another with a locking member, which is a tightening screw or similar mechanical locking member, which presses the pontic module halves or separate compressing parts against one another and locks the anchoring part’s support sphere to be immobile in relation to the pontic module.

In the support hollow inside the pontic module can be two adjustment parts or compressing parts between which the support sphere of the anchoring part is located. The adjustment parts and the support sphere between them can be moved in the support hollow such that the distance of the anchoring part connected to the support sphere from the pontic module can be changed.

In connection with the adjustment parts inside the pontic module halves is a locking member, with the help of which the adjustment parts and the support sphere between them can be locked in place. The locking member is a tightening screw or similar locking member which presses the adjustment parts against one another and locks the adjustment parts, the support sphere between them and the anchoring part connected to the support sphere to be immobile in relation to the pontic module.

The pontic module can also be formed by a uniform piece inside of which is a support hollow for two adjustment parts or compressing parts and their locking member. Between the adjustment parts is a support sphere to which the anchoring part is connected. The adjustment parts’ locking member is formed by a locking sheet and tightening screw, with the help of which the locking sheet can be pushed against the adjustment parts such that the locking sheet locks the adjustment parts, the support sphere between them and the anchoring part connected to the support sphere to be immobile in relation to the pontic module.

The modular bridge’s anchoring parts have protrusions which are attached to the abutment teeth’s cavities with cement, and adhesive or filling material has been placed between the parts of the modular bridge to lock in place the modular bridge parts to be immobile in relation to one another.

In the following, the invention is described using examples with reference to the appended drawings, in which

LIST OF FIGURES Figure 1 shows an axonometric projection of parts of a modular bridge according to the invention.

Figure 2 shows parts of a modular bridge according to the invention Figure 3 shows an axonometric projection of parts of a modular bridge according to the invention connected together

Figure 4 shows a side view of the modular bridge parts of Figure 3. Figure 5 shows a top view of a modular bridge according to the invention Figure 6 shows an axonometric projection of a modular bridge according to the invention and abutment teeth to which the bridge can be connected Figure 7 shows a top view of a modular bridge according to Figure 6 connected to the adjacent abutment teeth.

Figure 8 shows a vertical sectional view of a modular bridge connected to the adjacent abutment teeth.

Figure 9 shows an axonometric projection of parts of a modular bridge according to the invention.

Figure 10 shows a vertical sectional view of the modular bridge assembled from the parts of Figure 9, connected to the adjacent abutment teeth

Figure 11 shows an axonometric projection of parts of a modular bridge according to the invention. Figure 12 shows a vertical sectional view of the modular bridge assembled from the parts of Figure 11, connected to the adjacent abutment teeth

Figure 13 shows a vertical sectional view of a modular bridge according to the invention.

Figure 14 shows a horizontal sectional view of the modular bridge of Figure 13. Figure 15 shows a horizontal sectional view of a modular bridge according to the invention.

Figures 16 and 17 show an axonometric projection and top view of an anchoring part of a modular bridge according to the invention.

Figures 18 and 19 show an axonometric projection and top view of an anchoring part of a modular bridge according to the invention.

Figure 20 shows a vertical sectional view of the modular bridge according to the invention of Figures 16 and 17 connected to the adjacent abutment teeth

Figure 21 shows a vertical sectional view of the modular bridge according to the invention of Figures 18 and 19 connected to the adjacent abutment teeth Figure 22 shows an axonometric projection of parts of a modular bridge according to the invention. Figure 23 shows a vertical sectional view of a modular bridge according to the invention connected to the adjacent abutment teeth.

Figure 24 shows an axonometric projection of parts of a modular bridge according to the invention.

Figure 25 shows a vertical sectional view of a modular bridge according to the invention assembled from the parts of Figure 24, connected to the adjacent abutment teeth.

Figure 26 shows an axonometric projection of parts of a modular bridge according to the invention.

Figure 27 shows a vertical sectional view of a modular bridge according to the invention assembled from the parts of Figure 26, connected to the adjacent abutment teeth.

DESCRIPTION OF THE FIGURES

A fixed partial denture according to the invention is a modular bridge that has a pontic module comprised of one or more pontics and anchoring parts to be attached to the abutment teeth. The fixed partial denture according to the invention of Figure 1 is a modular bridge 1 which is comprised of industrially produced parts, which are in Figure 1 a pontic module 2 assembled from two parts and two anchoring parts 3. In Figure 1, the pontic module 2 is formed from two halves, between which the support spheres 4 of the anchoring parts 3 are placed. The halves of the pontic module 2 are locked together using a locking member, which is, for example, a tightening screw 5. Figure 1 shows apertures 6 in the pontic module 2 halves. When locking the pontic module 2 halves to one another, the tightening screw 5 equipped with a thread is threaded into the aperture 6 of the half on the right in the figure and rotated into the threaded aperture 6 in the opposite pontic module 2 half. The pontic module 2 halves of Figure 1 have, on the sides next to the abutment teeth, concave, essentially hemispherical recesses 7 that correspond with the size and shape of the anchoring parts’ 3 support spheres 4. When the pontic module 2 halves are placed against one another, the recesses 7 form in the pontic module 2 two essentially spherical spaces in which the anchoring parts’ 3 support spheres 4 can be placed such that the anchoring part’s 3 support sphere 4 can rotate in this spherical space. The protrusion of the anchoring part 3 to be connected to the abutment tooth comes out of the pontic module’s 2 spherical space through an opening 8. The opening 8 is dimensioned such that it prevents the support sphere 4 from slipping out of the recess 7. However, the opening 8 is so large that the protrusion of the anchoring part 3 to be connected to the abutment tooth can rotate in different directions with the support sphere 4 acting as a rotational axis. Thus, the anchoring part 3 support sphere 4 and pontic module 2 spherical space together form a joint supported by which the anchoring part 3 can be suitably directed such that the anchoring part 3 protrusion can be fitted to the abutment tooth or a cavity formed in it.

The mutual contact surfaces of the pontic module 2 spherical space and anchoring part 3 support sphere 4 can be roughened to ensure that the modular bridge 1 anchoring parts 3 and pontic module 2 lock to be immobile after the pontic module 2 halves have been pressed against one another using a locking member, which is for example a tightening screw 5.

The pontic module 2 halves of Figure 2 have, on the sides next to the abutment teeth, the anchoring parts’ essentially hemispherical recesses 7 replaced with essentially hemispherical recesses equipped with edge steps 46. The surface of the recesses can be formed from locking edges, whereby the sharp edges of the hemispherical recesses located in the pontic module 2 halves coincide with the support spheres from the opposite sides.

An alternative course of action is that instead of the support spheres 4 of one modular bridge anchoring part 3 or both anchoring parts there can be polygonal pieces which lock into the pontic module recesses 7 or the edge steps 46 replacing them with the tightening screw 5 pressing the pontic module 2 halves against one another. The polygonal pieces can also be connected with one or more shafts and/or pegs to the anchoring parts 3. If required, between the anchoring part 3 polygonal pieces and pontic module 2 halves’ recesses or edge steps replacing these, can be injected a highly liquid, chemically curing adhesive, cement or filling material along special channels as is shown in the example of Figure 10. This prevents the liquids in the mouth getting into this space to later cause a bad taste or smell in the mouth.

Figure 3 shows an axonometric projection of parts of a modular bridge 1 according to the invention, which include the other half of the pontic module 2 and both anchoring parts 3 to be installed on it. Figure 3 shows a situation in which the support spheres 4 of the anchoring parts 3 have been pushed into the recesses 7 of the pontic module 2 halves and the protrusions of the anchoring parts 3 point in opposite directions. In Figure 3, the other half of the pontic module is not shown to give a more illustrative view of the anchoring parts 3 and rotation supported by the support sphere 4. In the example of Figure 3, the midlines that run through the centre points of the support spheres 4 are perpendicular against the straight wall of the pontic module 2 half. The dotted lines drawn to intersect with them cut the transverse lines running through the biting surfaces of the protrusions of the anchoring parts 3 to be connected to the abutment teeth at the angles a and b. The rotation angles a and b can freely be changed independently of one another.

Figure 4 shows a side view of an example in which the support spheres 4 of the anchoring parts 3 have been pushed into the recesses 7 of the other half of the pontic module 2 of the modular bridge 1 according to the invention of Figure 3. The protrusions of the anchoring parts 3 have been turned in different directions, one downward and the other upward. As a result, the dotted line running through the centre points of the support spheres 4 cuts the longitudinal lines running through the biting surfaces of the protrusions of the anchoring parts 4 at the angles g and d. The turning angles g and d can freely be changed independently of one another.

Figure 5 shows a top view of a modular bridge 1 according to the invention which has a pontic module 2 assembled from two parts, i.e. two halves, with the protrusions of the anchoring parts 3 having been turned sideways in different directions, on the support spheres 4 located in the spherical spaces formed from the recesses 7 in the pontic module halves. The midline running along the joint line of the pontic module 2 biting surface cuts the longitudinal lines running via the midline of the biting surfaces of the anchoring parts’ 3 protrusions at the angles e and z. The protrusions’ laterally changing angles e and z can be changed independently of one another. An alternative course of action is for the straight walls of the pontic module 2 halves to be placed against one another to be partially or fully formed to be wavey and/or angular, but still perfectly fitted against one another. Thereby the joint line of the biting surface can be made to run in a winding pattern along the corresponding tooth’s anatomical surface grooves as inconspicuously as possible. Figure 6 shows a large cavity 11 and a small cavity 12 made in the abutment teeth 9 and 10 and extending from the side next to the missing tooth to the biting surface, the shape and size of which cavities correspond essentially with the anchoring parts’ 3 protrusions. If required, anchoring parts fitting the cavity can be selected by fitting to it different-sized, solid impressions of anchoring parts. A pontic module 2 assembled from parts of a suitable size, shape and colour selected from a prepared selection, to which pontic module anchoring parts 3 fitting the made cavities and their protrusions and support spheres 4 are connected. The halves of the assembled pontic module 2 are combined loosely enough with a tightening screw 5 that the protrusions of the anchoring parts 3 can be turned and/or rotated at the fitting stage.

Figure 7 shows a top view of a modular bridge 1 fitted to the abutment teeth 9 and 10 in place of a missing tooth. Figure 7 indicates the fit of the anchoring parts’ 3 protrusions to the differently orientated and different-sized cavities 11 and 12 of the abutment teeth 9 and 10, because the anchoring parts 3 can be rotated in relation to one another and their position can be changed in the pontic module 2 on the x, y and z coordinate system independently of one another as shown in Figures 3-5.

The vertical sectional view of a modular bridge 1 shown in Figure 8, shows the other half of the pontic module 2 and as a vertical sectional view seen on the level A-A of the midline of the pontic module 2 shown in Figure 7 the anchoring parts 3, support spheres 4, tightening screw 5, adjacent abutment teeth 9 and 10 with their cavities 11 and 12 and one bicuspid 14 adjacent to an abutment tooth. The assembled modular bridge 1 is fitted to the abutment teeth 9 and 10 by turning the protrusions of the anchoring parts 3 and rotating them on their support spheres 4 until the protrusions of the anchoring parts 3 are in an ideal position in the cavities 11 and 12 of the abutment teeth 9 and 10. If the protrusion of the anchoring part 3 and cavity of the abutment tooth are not exactly the same shape, a gap or empty space may remain between them, as shown in Figure 8. In the cavity 11 under the anchoring part has been left an empty hollow 15, which however is filled with cement and/or filling material in connection with the final attachment of the modular bridge. Both anchoring parts 3 can be turned and rotated on their support spheres 4 independently of one another. The turning of the anchoring part 3 in different directions is only limited by the joint between the support sphere 4 and anchoring part protrusion coinciding with the edge of the opening 8 formed by the recesses 7 in the pontic module 2 halves.

Prior to the final attachment in place of the modular bridge 1, the modular bridge 1 is cleaned and dried outside the mouth if required. Thereafter, curing adhesive is applied onto the modular bridge’s 1 tightening screw 5 and the mutual contact surfaces of the pontic module 2 halves and the support spheres 4 of the anchoring parts 3 to prevent the discoloration of seams and the loosening of parts due to different beverages and foodstuffs over the years. Immediately, a sufficient amount of luting cement is placed in the cavities 11 and 12 of the abutment teeth 9 and 10, into which luting cement the protrusions of the pre-assembled modular bridge’s 1 anchoring parts 3 are pushed. For the duration of the installation, onto the modular bridge’s 1 biting surface can be placed a separate plastic film 43 to prevent the cement from adhering to the opposite teeth when the jaws are occluded. This way the modular bridge 1 settles in the desired position in the place of the missing tooth, at the same time fitting with the occlusion of the teeth. After that, with a separate tool, the tightening screw 5 is tightened until the parts of the pontic module 2 press the support spheres 4 of the anchoring parts 3 between their pontic module 2 halves to be immobile to form a fixed modular bridge 1 from the pontic module 2 and anchoring parts 3. Finally, the apertures 6 made in the pontic module 2 halves for the tightening screw 5 are filled with filling material the colour of the tooth. Cement and filling excesses are removed mostly before they are cured and the modular bridge 1 and its anchoring parts 3 are kept tightly in the correct position during curing by biting the teeth together.

Alternatively, the cementation stages of the modular bridge can be carried out in two stages such that in the first stage, the modular bridge 1 is fitted into the cavities 11 and 12 of the abutment teeth, the dentition is occluded and the bridge’s tightening screw 5 is used to tighten the anchoring parts 3 to be immobile. If the modular bridge is easy to detach from the differently orientated abutment teeth, the first stage of the two-stage cementation can be carried out such that first the modular bridge is dismantled outside of the mouth and cleaned and dried if needed. Thereafter, as shown in Figure 8, curing adhesive is applied onto the mutual contact surfaces of the pontic module 2 halves and the support spheres 4 of the anchoring parts 3. The modular bridge 1 is assembled immediately and pushed into the abutment teeth’s bare cavities into which no cementing material has been spread. The teeth are occluded and the tightening screw is rotated tightly shut.

After the adhesive cures, the modular bridge 1 is detached, the cavities 11 and 12 and the anchoring parts are cleaned and dried. Thereafter, the second cementation stage is carried out, i.e. a sufficient amount of luting cement is placed in the cavities 11 and 12 of the abutment teeth 9 and 10, into which luting cement the immobile protrusions of the modular bridge anchoring parts 3 are pressed. The other measures as in Figure 8.

Figure 9 shows an axonometric projection of parts of a fixed partial denture 1 according to the invention. In this example, one anchoring part 3 with its support sphere 4 is in line with the solution shown in Figure 1 , but in the support sphere 4 of the other anchoring part 3 is an aperture 16, into which the anchoring part’s 3 support peg 17 fits. The length of the support peg 17 is slightly longer than the diameter of the support sphere 4 and the partial cracks 18 in the support sphere 4 allow the diameter of the support sphere aperture 16 to grow when the support peg 17 is placed in the aperture 16. Thereby, the anchoring part 3 does not come loose from the pontic module 2 when the assembled modular bridge 1 is being fitted into the mouth. The pontic module 2 has for the end of the support peg 17, a turning hollow 19, which connects to the essentially hemispherical recess 7 of the pontic module’s 2 half. Thereby, the anchoring part 3 can be turned to the sides and both upward and downward on the support sphere 4 within the limits allowed by the opening 8 in the essentially hemispherical recess 7 of the pontic module 2.

Figure 10 shows a vertical sectional view of a modular bridge 1 according to the invention assembled from the parts of Figure 9, connected to the adjacent abutment teeth 9 and 10. The modular bridge’s 1 other anchoring part 3 with its support sphere 4 is uniform and in the other anchoring part 3 the anchoring part 3 and the support sphere 4 are separate, such as shown in Figure 9. This structure allows the mutual distance between the pontic module 2 and the anchoring parts 3 to be changed steplessly, whereby the protrusions of the anchoring parts 3 can be made to fit precisely in the cavities 11 and 12 of the abutment teeth 9 and 10. At the same time, thereby only a few pontic modules 2 of different sizes are required for the opening points formed by extracted teeth of different lengths. In Figure 10, the space between the pontic module 2 and the posterior abutment tooth 9 is wider than the corresponding space in Figure 8. A suitable pontic module 2 has been achieved for this space because the anchoring part 3 has been moved on its support peg 17 into precisely the correct position in the corresponding cavity 11 of the abutment tooth 9. The entire length of the support peg 17 is still inside the support sphere 4. The turning hollow 19 located between the pontic module 2 halves is filled in connection with cementation through the filling channel 20 with chemically curing cementing or filling material. At the same time, the air in the hollow 19 exits through a discharge channel 21 to the external surface of the pontic module 2 close to the aperture 6 of the tightening screw 5. When the turning hollow 19 is filled with adhesive, there can be small side channels in the filling channel 20 along which the adhesive travels to all of the contact surfaces of the pontic module’s 2 parts. Other cementation, tightening of the tightening screw 5 and finishing are carried out as shown in Figure 8, filling all of the openings and apertures.

Figure 11 shows an axonometric projection of a pontic module 2 structure disassembled into parts. In the example shown in Figure 11 , the anchoring parts 3 and support spheres 4 are as shown in the example of Figure 1 , but inside the pontic module 2 halves is, for the movable adjustment parts 22, a precise support hollow 23 in which the adjustment parts 22 are possible to move until both of the anchoring parts’ 3 protrusions precisely coincide with the cavities 11 and 12 of the abutment teeth 9 and 10. Thereby, this structure also allows the mutual distance between the pontic module 2 anchoring parts 3 to be changed steplessly. In the back part of the support hollow 23 is a filling channel 20 and discharge channel 21 also in this embodiment. In the pontic module 2 of Figure 11 , the adjustment parts 22 press the support sphere 4 of the anchoring part 3 to be immobile with a separate adjustment screw 24 and the pontic module’s 2 tightening screw 5 ensures that the adjustment parts 22 pressed together remain in their final position in the support hollow 23 formed between the pontic module 2 halves. On one side of one of the pontic module’s 2 halves is the opening 26 of the adjustment screw 24, into which fits a tool that can be used to tighten the adjustment screw 24 such that the adjustment parts 22 are pressed into contact with the support sphere 4. On the inner surface of the pontic module 2 opening 26, for the adjustment screw 24 head, is an extension, which, at the same time, functions as a limiter preventing the adjustment parts 22 from sliding out too much or coming loose from the pontic module 2 at the fitting stage. A pontic module 2 assembled from two parts can also be pressed using a tightening screw 5 such that all of the parts 2, 22 and 4, which are mutually made to measure, can be made fully immobile.

Figure 12 shows a vertical sectional view of a modular bridge 1 according to the invention assembled from the parts of Figure 11 , connected to the adjacent abutment teeth 9 and 10. In this example, the anchoring parts 3 and the support spheres 4 are uniform as in Figure 8. Moving the adjustment part 22 in its support hollow 23 guarantees that the protrusions of the anchoring parts 3 precisely coincide with the cavities 11 and 12 of the abutment teeth 9 and 10. If the protruding lower part 27 of the adjustment part 22 plugs the opening above the gumline and between the pontic module 2 and abutment tooth 9, the lower edge 27 of the plugging adjustment part can be ground smaller after cementation of the modular bridge 1. Thereby is achieved a sufficiently large cleaning space at the gumline between the pontic module 2 and the abutment tooth 9. Behind the adjustment parts 22 after the fitting there may remain an empty support hollow 23, which is filled at the cementation stage, as described in the description of Figure 10. Finally, all of the pontic module’s 2 apertures and openings are filled and finished as described above. In Figure 13 is shown a vertical sectional view of a modular bridge 1 according to the invention, in which the pontic module 2 has been made to be a one-part piece already at the manufacturing stage. Thereby, on the sides next to each abutment tooth 9 and 10 of the one-part frame part 44 of the pontic module 2, support hollows 23 have been formed that open up towards the abutment teeth 9 and 10. The support hollows 23 inside the pontic module 2 frame part 44 can also be formed into a uniform tunnel. Into the support hollows 23 or the uniform support hollow have been threaded the adjustment parts 22 and the anchoring parts’ 3 support spheres 4 between them with the protrusions of the anchoring parts 3 remaining visible. The support spheres 4 of the anchoring parts 3 are pressed with the adjustment parts 22 to be immobile inside the pontic module 2 frame part 44. Figure 14 shows a horizontal sectional view of the modular bridge 1 of Figure 13. At the attachment stage of the modular bridge 1 the adjustment parts 22 with their support spheres 4 are locked to be immobile with a tightening screw 5 pressing the locking sheet 42 and the adjustment parts 22 into the support hollow’s 23 side wall. The adjustment parts’ 22, support spheres’ 4 and support hollow’s 23 mutual contact surfaces can be rough as is shown in Figure 1 , whereby the locking between the parts is made to be extremely strong. The support hollows 23 can be formed in both the horizontal and vertical direction to be such that the adjustment parts 22 can also be moved in relation to the height of the pontic module 2 biting surface. Thereby the pontic module 2 can be fitted into the spaces between the abutment teeth 9 and 10 that are of different widths, also at different heights in relation to the other teeth’s biting surfaces. The first cementation stage of the modular bridge 1 is carried out similarly as shown in the description of Figures 8 and 10.

In the examples presented above, at the fitting stage of the modular bridge 1 according to the invention, the tightening screw 5 or 24 of the pontic module 2 can be in the counter aperture 6 or 25 without pressing the adjustment parts 22 and/or the anchoring parts 3 together to be fully immobile. The parts still do not fall from their place in the support hollows 23 because under the head of the tightening screw 5 or 24 there can be a small coil spring which presses lightly on the locking sheet 42 and/or adjustment parts 22, preventing the parts from falling from the support hollows.

Figure 15 shows a horizontal sectional view of a modular bridge according to the invention in which the recesses 7 intended for the anchoring parts’ 3 support spheres 4 are equipped with edge steps 46. The recesses 7 are still essentially hemispherical such that the support spheres 4 of the anchoring parts 3 fit well into the recesses 7. When the adjustment parts 22 are not pressed against the support spheres 4, the anchoring parts 3 can easily be turned. After the adjustment parts 22 are pressed against the support spheres 4 such that the sharp edges of the recesses’ 7 edge steps 46 coincide with the support spheres from its opposite sides. Thereby, the support spheres 4 and at the same time the anchoring parts 3 are firmly locked in place.

The cementation of the modular bridge of Figure 15 is carried out in the same way as described above. Inside the support hollows 23 or uniform support hollow can be placed one or more separate springs behind the adjustment parts 22 to press the adjustment parts slightly outward from the pontic. Thereby, the anchoring parts 3 are easier to put in the correct position in the cavities 11 and 12 of the abutment teeth at the cementation stage. Similar springs can also be used in the modular bridges according to the invention of Figures 10, 12, 13 and 14.

Figure 16 shows an axonometric projection of the anchoring parts 3 of a modular bridge 1 according to the invention and in Figure 17 they are seen from the top. The support spheres 4 of the anchoring parts 3 can be as shown in Figure 1 , but in the anchoring parts the shapes on the sides next to the biting surfaces and abutment tooth are different. The anchoring part biting support 28 extends only over a small part of the biting surface and thus when making a corresponding cavity, relatively little hard dental tissue is removed. On the side of the anchoring part next to the abutment tooth has been formed a flange 29, which fits as well as possible onto the abutment tooth’s intact side surface.

Figures 18 and 19 show anchoring parts 3 of a modular bridge according to the invention, which parts fit crowned teeth. Figure 18 shows an axonometric projection of the anchoring parts 3 with locking screws 31 and in Figure 19 they are seen from the top.

The anchoring parts 3 of Figures 18 and 19 differ from those shown in Figure 1 such that the anchoring part 3 has, instead of a protrusion placed in the cavity of the abutment tooth 9 and/or 10, a support hook 30, which is attached to a support aperture made in the biting surface of the abutment tooth 9 and/or 10. The staying of the support hook in the support aperture is ensured after cementation and/or gluing with a small locking screw 31, which leans on an counter groove 32 on the biting surface of the support hook 30 of the anchoring part 3. Figure 20 shows a vertical sectional view of a modular bridge 1 according to the invention, connected to the adjacent abutment teeth 9 and 10. The solution shown in Figure 20 essentially corresponds with the solution shown in Figure 8, which shows the other half of the pontic module 2, abutment teeth 9 and 10, tightening screw 5, the biting supports 28 and flanges 29 of the anchoring parts shown in Figures 16 and 17. Small cavities for the biting supports have been ground into the abutment teeth 9 and 10 on the side of the pontic module 2 only in the biting surface. The cavities partly chamfer the edge of the abutment tooth. At the flanges 29, the surface of the abutment tooth has only been treated with known methods, so that the gluing of the flanges on the enamel surface is successful. The biting support absorbs the greatest bite stress and in addition the glued flange prevents the entire modular bridge from coming loose and rotating. Otherwise, the final attachment is carried out in the same way as shown in the examples presented above. There are anchoring parts and their biting supports and flanges in different sizes, shapes and colours.

Figure 21 shows a vertical sectional view of a modular bridge 1 according to the invention, connected to the adjacent abutment teeth 9 and 10, which have prosthetic crowns 33. In the example of Figure 21, into the prosthetic crowns 33 of the abutment teeth 9 and 10 have been drilled support apertures for the support hooks 30 of the anchoring parts 3 shown in Figure 18 and 19 and diagonal apertures 34 for the locking screws 31 of the anchoring parts 3. The support aperture for the support hook 30 for the anchoring part 3 is made starting from the tooth’s biting surface into the prosthetic crown 33 into the hard tissue of the abutment tooth 9 and/or 10 approximately in the longitudinal axis of the abutment tooth 9 and/or 10 such that some of the intact prosthetic crown 33 partly remains on the tooth edge to support the support hook 30. The support apertures are made with a special drill the size of which corresponds with the support hook 30 of the anchoring part 3. The drill has a limiter, which prevents drilling too deep.

In Figure 21 is a diagonal aperture 34 made in the abutment tooth 10 with a suitably sized drill for the locking screw 31. The aperture 34 of the locking screw 31 is parallel to the counter groove 32 of the support hook 30 of the anchoring part 3 shown in Figure 19. The locking screw 31 of the posterior abutment tooth 9 has already been attached to its aperture 34. Finally, the installation of the anchoring parts 3 is finalised by removing the parts of the locking screws 31 that remain visible up until the biting surfaces of the abutment teeth 9 and 10.

Figure 22 shows an axonometric projection of the parts of a modular bridge 1 according to the invention. In Figure 22, the pontic module 2 has a separate, exchangeable lower part 35, which can be changed if required for one or more parts of a different size and/or shape. Thereby, it is possible to form in the depression in the place of the extracted tooth a pontic module 2 that is always the right size, which is at the same time in contact with both the gumline and the antagonist during occlusion. The exchangeable lower part 35 is attached to the pontic module 2, for example such that in the lower part 35 is one or more grasping pegs 36, which are formed to lock with the counter hole 37 of the grasping peg in the adjacent part of the pontic module 2. The parts of the pontic module 2 shown in Figure 22 are connected with one another into a uniform piece such that the tightening screw 5 is used to press the pontic module 2 halves together, whereby the grasping peg 36 of the lower part 35 gets caught in the counter hole 37 between the halves. The exchangeable lower part 35 can be coupled to be part of the pontic module 2 also in some other mechanical manner.

Figure 23 shows a vertical sectional view of a modular bridge according to the invention formed from two pontic parts, which is connected to the adjacent abutment teeth. The modular bridge of Figure 23 has, in addition to one pontic 2, a second pontic 45. The pontics of the bridge are combined with one another with a two-part joint sphere 38.

Because the pontic modules 2 and 45 located next to one another are connected to one another with a two-part joint sphere 38, the mutual position of both pontic modules can be varied and the modular bridge 1 can be brought in the desired position supported by the abutment teeth 9 and 10 during occlusion to fit with the antagonist.

Figure 24 shows parts of a modular bridge 1 according to the invention and Figure 25 shows a vertical sectional view of the modular bridge 1 assembled from parts shown in Figure 24 attached to the adjacent abutment teeth 9 and 10. This example shows a small sized pontic module 2, the internal design of which has been changed such that the opening point of a very small missing tooth is possible to replace with a pontic module 2. The concave, essentially hemispherical recesses 7 corresponding to the anchoring part’s 3 support spheres 4 in the pontic module 2 shown in Figures 24 and 25 intersect one another, forming a uniform double hollow. Correspondingly, an amount can be cut away from the opposing sides 39 of the support spheres 4 of the anchoring part 3 so that the support spheres 4 of two anchoring parts 3 together fit into the double hollow formed by the recesses 7 in the pontic module 2 halves. With this arrangement, the anchoring part 3 can freely be fitted in different positions to the abutment teeth 9 and 10. An empty space can remain between the cut opposing sides 39 of the anchoring parts’ 3 support spheres 4, which space can be filled in connection with cementation along the filling channel 20 in the manner presented above.

Figure 26 shows parts of a modular bridge 1 according to the invention and Figure 27 shows a vertical sectional view of the modular bridge 1 assembled from parts shown in Figure 26 attached to the adjacent abutment teeth 9 and 10. This example also shows a small-sized pontic module 2, which can be used when a missing tooth’s opening point is very small. In the examples shown in Figures 26 and 27, the support sphere 4 of the anchoring part 3 has not been connected permanently to the anchoring part 3. The anchoring part 4 has been connected to the pontic module 2 such that the support sphere 4 has been placed in the spherical space formed by the recesses 7 in the pontic module’s 2 halves, when two halves of the pontic module 2 are placed opposite against one another. The anchoring part 3 is connected to the pontic module 2 such that the anchoring part 3 has a support cup 40 with a concave middle corresponding to the size and shape of the support sphere 4, which support cup rests against the support sphere 4 in the pontic module 2. In this instance, the connecting of the two anchoring parts 3 to the pontic module 2 at different sides of it can be carried out such that there are two spherical spaces in the pontic module 2 into which separate support spheres 4 are placed. The anchoring parts 3 are placed on different sides of the pontic module 2 such that the hemispherical concave support cup 40 of the anchoring part 3 is pressed against the support sphere 4 on the corresponding side.

The connecting of the two anchoring parts 3 to the pontic module 2 at different sides of it can be also carried out such that in the pontic module 2 there is a double hollow formed by two hemispherical recesses, in which is placed a small two-part inner sphere 41 that is reminiscent in shape of the two-part joint sphere 38.

The anchoring parts 3 are placed on different sides of the pontic module 2 such that the hemispherical concave support cup 40 of the anchoring part 3 is pressed from the corresponding side against the inner sphere 41 in the pontic module 2. The inner sphere 41 is loose and the concave support cups 40 of the anchoring parts 3 precisely coinciding with the outer surfaces next to the abutment teeth 9 and 10 turn and rotate when moving the anchoring parts 3. When the tightening screw 5 presses the halves of the pontic module 2 together, the concave support cups 40 and the one-part support sphere 4 or the two-part inner sphere 41 remaining between, together with the anchoring parts 3, lock into a uniform modular bridge 1. Between the support cups 40 an empty space can remain, which is filled as presented above. The above-described modular bridge 1 structure enables the making of different-sized pontic modules 2 by changing the length remaining between the support cups 40 of the two-part inner sphere 41 while the size of the spheres 4 or 41 remains the same and by adjusting the pontic module 2 and its recesses 7 to a corresponding dimension. Connecting two anchoring parts 3 to the pontic module 2 on its different sides can also be carried out such that in both halves of the pontic module 2 is just one hemispherical recess 7, which together form one spherical space when the halves of the pontic module 2 are pressed against one another. Thereby, just one sphere, which is for example a symmetrical support sphere 4, can be used as the inner sphere. Thereby, the anchoring parts 3 are placed on different sides of the pontic module 2 such that the hemispherical concave support cup 40 of the anchoring part 3 is pressed from the corresponding side against the support sphere 4 in the pontic module 2. In all of the shown modular bridges according to the invention, a strong bite stress is placed on the anchoring part 3 and thus the fixed joint of the anchoring part with the support sphere 4 or concave support cup 40 must be made as stable and thick as possible. Still the fixed joint does not restrict too much the turning of the anchoring part when the modular bridge is fitted into the abutment teeth cavities 11 and 12.

According to the invention, the different alternatives presented above can be combined, by adapting them, with one another and it is possible to replace missing teeth with these combinations even in many kinds of clinically challenging cases. Thereby, for example the structures shown in Figures 1-15 can be combined with the solutions shown in Figures 16-23. The structures of Figures 24-27 can also be combined with the above-mentioned alternatives by changing the other sphere of the two-part joint sphere 38 to correspond with the support sphere’s cut opposing side or the concave support cup 40.

LIST OF REFERENCE NUMBERS

1 Modular bridge

2 Pontic module

3 Anchoring part

4 Support sphere 5 Tightening screw

6 Tightening screw’s counter aperture

7 Essentially hemispherical recess

8 Recess opening

9 Posterior abutment tooth 10 Anterior abutment tooth

11 Large cavity

12 Small cavity 13 Dotted line of anchoring part’s longitudinal midline

14 Second bicuspid

15 Empty hollow under the anchoring part

16 Support sphere’s aperture 17 Anchoring part support peg

18 Support sphere’s partial cracks

19 Turning hollow of the support peg head

20 Filling channel 21 Air discharge channel 22 Adjustment part

23 Adjustment part support hollow

24 Adjusting screw

25 Adjusting screw’s counter aperture

26 Adjusting screw opening 27 Adjustment part’s protruding lower part

28 Anchoring part biting support

29 Anchoring part flange

30 Anchoring part support hook

31 Locking screw 32 Counter groove of support hook’s locking screw

33 Prosthetic crown

34 Locking screw’s diagonal aperture

35 Pontic module’s exchangeable lower part

36 Exchangeable lower part’s grasping peg 37 Grasping peg’s counter hole

38 Two-part joint sphere

39 Support sphere’s cut opposing side

40 Concave support cup

41 Inner sphere comprised of one or two parts 42 Adjusting part’s locking sheet

43 Plastic film

44 Frame part of pontic module

45 Second pontic

46 Edge steps made into adjustment part’s recess