WO2018037252A1

WO2018037252A1 - Prosthesis arrangement

Info

Publication number: WO2018037252A1
Application number: PCT/HU2017/050034
Authority: WO
Inventors: Sándor OLASZ; Zoltán Csaba EDVI
Original assignee: Olasz Sandor; Edvi Zoltan Csaba
Priority date: 2016-08-24
Filing date: 2017-08-23
Publication date: 2018-03-01
Also published as: HU231067B1; HUP1600494A2

Abstract

The invention discloses a prosthesis arrangement for using in prosthetic dentistry, comprising a dental implant (104) inserted in a jawbone (103), a first abutment part (120) inserted into the implant (104), a second abutment part (110) mounted on the first abutment part (120) along a second surface area (120b) of the first part (120), a first locking section (126) having isogonic surface, and said second surface area (120b) of the first part (120) is provided with a second locking section (122) having isogonic surface with an angular spacing different to the angular spacing of the first locking section (126); and the isogonic surface of at least one of the locking sections (122,126) is formed with a prime number of angles being greater than ten.

Description

PROSTHESIS ARRANGEMENT

The present invention relates to a prosthesis arrangement for using in prosthetic dentistry comprising an edosseous dental implant adapted to be inserted in a jawbone, a base part inserted into the cavity of the implant along a first surface area of said base part provided with a hole having an axis aligning with the axis of the cavity of the implant, a screw for fixing the base part in the implant, an abutment part mounted on the base part along a second surface area of the base part, and also relates to said base part for a prosthesis arrangement, wherein the base part has a first surface area and a second surface area and is provided with a bore.

A dental prosthesis can be done by a variety of different solutions, eg. by so called edosseous screw implant, or a pinned subperiosteal plate, a discos or basal implant, etc. For screwed implants implanted in the jaw bone two main types are known: one -part and two-part implants.

When implanting two-part implants, the final prosthetic body, ie. the abutment is attached to the implant after several weeks of implanting the im- plant, and a dental crown or bridge is glued or screwed on this abutment, since the coefficient of elasticity of the bone differs significantly from that of the materials of artificial root implants so that some early load acting to the implant may result in too much micro molecular displacements endangering proper ossification. Two-part implants are coupled nowadays mostly titanium or ceramic abutments by a screwed connection.

Prefabricated abutments and zirconia based abutments made by dental prosthetists using CAD / CAM technology and often baked by no sufficient accuracy can also be obtained in the market. Designing the abutment, dental prosthetists must adjust the correct direction and angle and adjust the prosthetic body to the height of the gum. One-part titanium alloy based abutments are typically used at molar part, while at the front part a more aesthetic result can be achieved by using ceramic prosthetic body, since over the years a certain degree of necrosis of the gums and bone tissue is unavoidable. Titanium abutments are easily machinable, their toughness is good and having high strength but after insertion they are in vivo blackened and in case of increased gingivitis may become visible on frontal or premolar parts at the shank of the base of the artificial crown.

It is well known that ceramic is an excellent base material for osteointegration and biocompatibility: it is an ion-bonded, chemically stable compound with a dental function against so called plaque and infections as well. However, the general disadvantage of ceramic materials is that they are brittle, sensitive to fatigue, having small fracture toughness and limited bearing power for tensile and bending stresses, with a high hardness after baking, too, so their subsequent machining is cumbersome and, in addition, microcracks are occurred on their surfaces while grinding.

However, bending stress is unavoidable for dental applications, average angular separation of the implant axis to the normal vector of the occlusal plane is 15°, and the angular correction is ensured by axial rotation of the abutment. In the case of one-piece ceramic abutments there is an increased risk of crushing - nowadays, many constructions combine a ceramic bolt with an intermediate component having a metal base, so these are hybrid abutments.

Patent document US 6244867 discloses a multipart abutment and a screwed base for angle adjustment. Although the invention increase the angular correction possibilities by using an inner inset piece, the main disadvantage of the solution is that coaxial centering is not appropriate, load bearing surfaces for blocking angular rotation can move by bending loads, which can lead to loosening of the assembly and even the loss of the implant.

U.S. Pat. No. 5,281,140. discloses a solution providing a variety of positions of rotation available through the intermediate polygonal collar-engaging component. The intermediate component can be fitted to the implant by means of a lower polygonal collar providing anti-rotation effect and it can be fitted to the abutment by means of an upper polygonal collar as well. Thus the product of numbers of angle of the two collar surfaces provides the allowable number of angular positions. However, if the of two numbers of angles have a common di- visor the number of allowable angular positions is actually smaller than the value of their product, since equal angular positions occur as well limiting the number of different angular positions of the abutment. For example, when the number of angles on the lower collar is six and that is nine on the top or vice versa, a circumferential point of the abutment can take up only to eighteen dif- ferent angles from the fifty-four angular positions around the abutment axis as six and nine have a common divisor: the three. This means that the angular position of the abutment can be set by every subsequent 360/18 = 20 degrees, because the remaining thirty-eight angular positions coincide with two-two angular positions of these 18 angular positions, that is remain unexploited. So, for ex- ample, we need to double the number of upper angles to achieve adjustment possibility of steps by 10 degrees, but in this case forming the 36 angular positions located at every 10 degree requires 18 upper angular positions corresponding to a total angular positions of 108 needed but remained mainly unexploited, that makes the precise working process of polygonal surface of the abutment to be extremely labor-intensive.

We have recognized that if the number of angles of at least one of the two polygons is a prime number, all the angular positions can be exploited, since the lower and upper numbers of angles do not have a common divisor different from 1 and itself. If, for example, the lower number of angles is 6 and 5 on the top, all of 30 angular positions are in different angular positions and the abutment can be adjusted by 12 degrees.

Therefore, the object of the present invention is to provide a multipart dental prosthesis comprising an implant, a hollow base fitted in the implant and an abutment holding the artificial crown mounted thereon, wherein forming process of polygonal form locking surfaces is simple and inexpensive due to few number of angles to be created and despite having few angles the angular adjustment of the abutment can be varied by adequately small angular spacings without, for example, the bending strength of the abutment would be deteriorated by any post-machining operation. At the same time the form locking arrangement is suitable for anti-rotational fixing of artificial crowns of so-called 'solo' implants as well. Our further aim is to develop a base part suitable for use in a prosthesis arrangement.

Above objects can be achieved by a prosthesis arrangement according to the invention for using in prosthetic dentistry comprising an edosseous dental implant adapted to be inserted in a jawbone, a base part inserted into the cavity of the implant along a first surface area of said base part provided with a hole having an axis aligning with the axis of the cavity of the implant, a screw for fixing the base part in the implant, an abutment part mounted on the base part along a second surface area of the base part, said first surface area of said base part is provided with a mounting cone section tightly fitted in the cavity of the implant along the direction of said axis; a cylindrical section; and a first locking section having a surface with a cross section of isogonic polygon, and said se- cond surface area of the base part is provided with at least one cylindrical section extended in axial direction, and a second locking section having a surface of isogonic polygon with an angular spacing different to the angular spacing of the first locking section; and the isogonic surface of at least one of the locking sections is formed with a prime number of angles being greater than ten.

A rim adapted for mounting the abutment part is formed between the first surface area and the second surface area of the base part.

The second surface area of the base part is provided with two cylindrical sections along the direction of said axis, and the second locking section is arranged between said two cylindrical sections.

The fixing screw has an Allen key aperture, and a fastening flange is arranged around the aperture.

The polygonal surface is a surface formed by curved surfaces.

The polygonal surface is a surface formed by plane plates.

Above objects can also be achieved by a base part for a prosthesis arrangement, wherein the base part has a first surface area and a second surface area and is provided with a bore, and its first surface area extending along the axial direction of the bore is provided with an adjusting cone section and a cylindrical section and a first locking section having a surface with a cross section of isogonic polygon, and the second surface area extending along the axial direction of the bore is provided with at least one cylindrical section, and a second locking section having a surface with a cross section of isogonic polygon with an angular spacing different to the angular spacing of the first locking section, and the isogonic surface of at least one of the locking sections is formed with a prime number of angles being greater than ten.

A rim is formed advantageously between its first surface area and its second surface area.

The second surface area is provided with two cylindrical sections along the axial direction, and the second locking section is arranged between said two cylindrical sections. The polygonal surface is a surface formed of curved surfaces angularly spaced.

The polygonal surface is a surface formed of planar surfaces angularly spaced.

The invention will now be described in details by reference to the accompanying drawing. In the drawing

Fig. 1 shows a prosthesis arrangement according to the invention comprising a dental implant implantable in a jaw bone, a base, a bolt and an abutment,

Fig. 2. is a section taken along the line A- A of Fig. 1 depicting an advantageous embodiment of the polygonal connection between the base and the abutment according to the invention,

Fig. 3. and 4. are sections taken along the line A-A of Fig. 1 depicting fur- ther advantageous embodiments of the polygonal connection between the base and the abutment according to the invention.

Figure 1 illustrates a prosthesis arrangement according to the invention comprising an edosseous dental implant 104 adapted to be inserted in a jawbone 103, a base part 120 made of e.g. titanium alloy to be inserted into the cavity 104a of the implant 104 and provided with a hole having an axis T aligning with the axis of the cavity 104a of the implant 104, a screw 130 for fixing the base part 120 in the implant 104 having preferably an Allen keyway opening 131, and an abutment part 110 mounted on the base part 120, wherein an artificial crown 101 can be built on the abutment part 110. At least one first surface area 120a of outer skirt surface of the base part 120 and inner surface of the cavity 104a of the implant 104 can be firmly inosculated. First surface area 120a of the base part 120 to be fitted into the cavity 104a is divided into a plurality of sections along the direction of axis T. In a preferred embodiment shown in the figure a first locking section 126 having an equilateral polygonal surface preventing relative rotation of the base 120 and the implant 104 is formed between a mounting cone section 125 firmly fitted in the cavity 104a of the implant 104 and a cylin- drical section 127. A fastening flange 132 can be formed around the Allen key- way opening 131 of the screw 131, which further improves the strength of the connection between the abutment 110 and the base part 120 along with gluing.

The mounting cone section 125 of the base part 120 is limited by a flange 124, to which the abutment 110 can be fitted. The outer surface of the base part 120 is provided with a second surface area 120b extending between the flange 124 and the upper rim 120c of the base part 120.

In this preferred embodiment, the second surface area 120b is divided into two cylindrical sections 121, 123 and a second isogonic polygonal locking section 122 arranged between the sections 121,123. Abutment 110 with an inner bore 111 may be fitted onto the area 120b of the skirt surface of the base part 120 such that at least a portion of the surface of the inner bore 111 fits to the second surface area 120b. It can be seen that a relative rotation of the base part 120 and the abutment 110 is prevented by fitting of the polygonal locking section 122 and the similar polygon formed on the inner surface of the bore 111 of the abutment 110.

Final fixing of the abutment 110 attached to the implant 104 by means of the base part 120 in the direction of axis T can be achieved e.g. by a screw 130 with internal Allen keyway opening 131. Then an aesthetic, e.g. adhesive- bonded artificial crown can be built onto the firmly fixed abutment 110.

The figure clearly shows that the superstructure, i.e., the abutment 110 and the artificial crown 101 fixed to the base parti 20, attached to the implant 104 implanted into the bone, is in direct contact with a soft tissue, the gingiva 102. The mounting region of the superstructure is considered to be highly risky for infection due to the rich bacterial flora of the oral cavity. Recession and tabescence of the surrounding living tissue, ie the gingiva 102 and the jawbone 103 is actually unavoidable some years after implantation. It is aesthetically more advantageous and biologically reduces the risk of infection if the mate- rial of the abutment 110 is a ceramic composite, but it is a tough, hard and microfissure sensitive material, so it is of utmost importance to reduce the risk of any break. Not individual, eg. CAD / CAM designed prefabricated superstructures are usually worked by the dental prosthetist into final form. The prosthetist chooses from a group of prosthesis arrangements being compatible with a given implant 104 the height of the shoulder 113 of the abutment 110 best approaching the given implanting position and also chooses the inclination relative to the closest axis T, being usually 0°, 15° or 30°, which is generally grinded further, and adjusts the shoulder 113 of the abutment 110 by a small extent (about 0.3-1 mm) below the gingiva 102.

Angular adjustment possibilities around axis T of a one-piece superstructure according to the prior art is solely determined by configuration of the locking section 126 limiting the relative rotation of the implant 104 and the abutment 110 the latter formed as a single piece with the base part 120, that is there are generally 3, 4, 6, 8 or 12 positioning direction allowed by a given implant sys- tern, that is often insufficient, so that for achieving the angular correction of the superstructure around the axis T also the skirt surface of the prefabricated abutment 110 must be formed by hand, eg. by grinding, and inaccuracy of this operation further increases the risk of breaking the ceramic composite material of the abutment 110.

In the case of a two-piece superstructure according to US 5,281,140 additional angular correction by grinding is less considerable, affecting favorably the risk of fracture, but the upper polygonal form locking section increasing the angular correction possibilities in some extent takes the flexural torque acting be- tween the abutment 110 and the base parti 23. However, the risk of fracture can be reduced substantially if much more angular adjustment positions are provided around the T-axis, instead of achieving any angular correction of the superstructure by grinding.

As the metal base part 120 and the ceramic abutment 110 begin to engage at the flange 124, the flange 124 conveys a large portion of the compression load to the base part 120. The continuation of the flange 124 of the base parti 20 is cylindrical or slightly conical section 123, which positions and stabilizes the ceramic abutment 110 perpendicularly to the axis T on the one hand, and transmits bending stresses to the base part 120 on the other. In the case of an angular correction around axis T increased bending stress acts on the ceramic abutment 110 close to the flange 124, therefore, a cylindrical or slightly conical design is used at this section 123, avoiding alterations in the arm of the force acting on the abutment 110 perpendicularly to axis T, occurring occasionally in a form lock- ing arrangement preventing rotation. The locking section 122 bearing a more moderate bending stress and situated over the section 123 has a form locking feature, it is e.g. polygonal, which prevents the relative rotation of the abutment 110 and the base part 120. It is further possible to reduce the risk of fracture so that the bending moment acting between the abutment 110 and the base part 120 is to be borne by a part being independent of the form locking section 122 acting as angular adjustment device, preferably the cylindrical section 123.

Preferably, the flange 124 for fitting the abutment 110 is formed between the first surface areal20a and the second surface area 120b of the base partl20. The second surface area 120b of the base part 120 is preferably provided with at least one cylindrical section 121,123 along the axis T but, for example, in the case of using two cylindrical sections 121,123, the second locking section 122 can conveniently be arranged between the two cylindrical sections 121,123. Figure 2 is a sectional view along line A- A of Figure 1, showing the locking connection between the base part 120 and the abutment 110, which in this preferred embodiment is a prime numbered isogonic rectangular polygon formed in the locking section 122 of the second surface area 120b of the base part 120. For this design, sufficient number of angular positions can be provided without deteriorating bending strength of the abutment 110, since by rotating the base part 120 around the axis T in 360° the abutment 110 may always located at different angles without any reoccurrence. If the base part 120 and the abutment 110 are rotated into the optimal direction, the two parts can be glued together. Since the abutment 110 and the base part 120 have prime numbered angular positions, number of angles of connection formed on the locking section 122 does not have any commonly divisor with the number of angles in the first locking section 126 of the implant 104, relative positions of angles between the abutment 110 and the base part 120 is equal to the product of number the angles of the locking sections 122,126 without any reoccurrence of angular positions, except when locking sections 122,126 are polygons of the same prime number, of course. For example, in case of using the hexagonal first locking section 126 and a second locking section 122 having eleven angles; the abutment 110 can be adjusted to sixty-six different angles around the axis T, which means a minimum angular distance of 5.45°.

Such a large number of different angular positions can only be achieved by means of an extremely large number of angles if none of the locking sections 122,126 have a prime number. For example, in the case of using a hexagonal first locking section 126 and a twelve angled second locking section 122, the abutment 110 can be set to seventy-two angular positions around the axis T indeed, but the numbers of angles of the two polygons do have common divisors different from the ones own, namely the number two and the three, that is only twelve angular positions, that is one sixth (2 * 3 = 6) of all possible seventy-two angular positions are different from each other meaning the least angular distance is 30° in contrast with 5.45° above. When, preferably, a prime number greater than 10 is used, a sufficiently small angular distance is available to adjust the abutment 110 adequately.

As the cylindrical form of the cylindrical section 127 so the metal base part 120 and the ceramic abutment 110 are fitted together advantageously by another cylindrical section 121 above the locking section 122 in order to displace in the direction of axis T the effect of bending moment acting on the locking section 122 as well.

Thus, in the case of using a locking section 126 having an arbitrary number of angular spacing and a locking section 122 with a different angular spacing of a prime number (or vice versa), unnecessary duplicate angular positions can be avoided, since the angular spacing of the two locking sections 122,126 do not have a single common divisor so that, each angle combination can be exploited, and the compulsory and break-risk increasing post-working of the skirt of the abutment 110 becomes unnecessary, since the number of possible angular positions according to the prior art is significantly increased, while their angular spacing is greatly reduced.

Therefore, the isogonic surface of at least one of the locking sections 122,126 of the prosthesis arrangement according to the present invention is formed with a prime number of angles.

Figures 3 and 4 are also sectional views along the line A-A of Fig. 1 in the case of further preferred embodiments, wherein the locking section 122 providing connection of the base part 120 and the abutment 110 is visible in cross-section. It can be seen from the figures that the locking section 122 can be formed as a pinion (Fig. 3) or even a sprocket (Fig. 4) or a similar part with curved surfaces instead of a regular polygon formed by planar surfaces, provided that this design has elements with a cross section having the same and con- gruent arrangement by equal angular spacings viewed perpendicularly to the axis T.

Therefore, the main advantage of the multipart dental prosthesis to be implanted in a jaw bone according to the present invention as compared to the so- lutions of the prior art is that production process of polygonal form locking surfaces is simple and inexpensive due to the few number of angles to be created and despite having few angles the angular adjustment of the abutment 110 can be varied by adequately small angular spacings without, for example, the bending strength of the abutment would be deteriorated by any post-working opera- tion.

Claims

1. Prosthesis arrangement for using in prosthetic dentistry, comprising an edosseous dental implant (104) adapted to be inserted in a jawbone (103), a base part (120) inserted into the cavity (104a) of the implant (104) along a first surface area (120a) of said base part (120) provided with a hole having an axis (T) aligning with the axis of the cavity (104a) of the implant (104), a screw (130) for fixing the base part (120) in the implant (104), an abutment part (110) mounted on the base part (120) along a second surface area (120b) of the base part (120) characterized in that said first surface area (120a) of said base part (120) is provided with a mounting cone section (125) tightly fitted in the cavity (104a) of the implant (104) along the direction of said axis (T); a cylindrical section (127); and a first locking section (126) having a surface with a cross section of isogonic polygon, and said second surface area (120b) of the base part (120) is provided with at least one cylindrical section (121,123) extended in axial (T) direction, and a second locking section (122) having a surface of isogonic polygon with an angular spacing different to the angular spacing of the first locking section (126); and the isogonic surface of at least one of the locking sections (122,126) is formed with a prime number of angles being greater than ten.

2. The prosthesis arrangement according to claim 1, characterized in that a flange (124) adapted for mounting the abutment part (110) is formed between the first surface area (120a) and the second surface area (120b) of the base part (120).

3. The prosthesis arrangement according to claim 2, characterized in that the second surface area (120b) of the base part (120) is provided with two cylindrical sections (121, 123) along the direction of said axis (T), and the second locking section (122) is arranged between said two cylindrical sections (121, 123).

4. The prosthesis arrangement according to claim 3, characterized in that the fixing screw (130) has an Allen key aperture (131), and a fastening flange ( 132) is arranged around the aperture (131).

5. The prosthesis arrangement according to claim 4, characterized in that the polygonal surface is a surface formed by curved surfaces.

6. The prosthesis arrangement according to claim 4, characterized in that the polygonal surface is a surface formed by plane plates.

7. A base part (120) for a prosthesis arrangement, wherein the base part (120) has a first surface area (120a) and a second surface area (120b) and is provided with a bore, characterized in that its first surface area (120a) extending along the axial (T) direction of the bore is provided with an adjusting cone section (125) and a cylindrical section (127) and a first locking section (126) having a surface with a cross section of isogonic polygon, and the second surface area (120b) extending along the axial (T) direction of the bore is provided with at least one cylindrical section (121, 123), and a second locking section (122) having a surface with a cross section of isogonic polygon with an angular spacing different to the angular spacing of the first locking section (126), and the isogon- ic surface of at least one of the locking sections (122,126) is formed with a prime number of angles being greater than ten.

8. The base part (120) according to claim 7, characterized in that a flange (124) is formed between its first surface area (120a) and its second surface area (120b).

9. The base part (120) according to claim 8, characterized in that its second surface area (120b) is provided with two cylindrical sections (121, 123) along the axial (T) direction, and the second locking section (122) is arranged between said two cylindrical sections (121, 123).

10. The base part (120) according to claim 9, characterized in that the polygonal surface is a surface formed of curved surfaces angularly spaced.

11. The base part (120) according to claim 9, characterized in that the polygonal surface is a surface formed of planar surfaces angularly spaced.