The present invention relates to a dental implant and dental prosthesis assembly system and method. In particular, but not exclusively, the present invention relates to a dental implant and dental prosthesis assembly system and method comprising a polymeric material and a dental abutment formed from a polymeric material.

It has been found that PAEK polymer, also including PEEK (polyetheretherketone) polymer is useful in the manufacture of dental prostheses, which are typically manufactured by shaping a block of the polymer material, commonly referred to as a dental disc, by means of computer-aided milling. The resulting dental prostheses are affixed to a patients jaw via fixtures implanted into the jaw in order to restore dental appearance and function.

WO2015092391 discloses a method for forming an integrated or repaired dental framework from a polymeric material.

SUMMARY OF INVENTION

According to a first aspect there is provided a dental implant and dental prosthesis assembly system comprising:

a dental implant having a gingival end and an implantable end;

a dental prosthesis; and

a dental abutment formed from a composition comprising or consisting of a polymeric material, the dental abutment comprising:

a body having a first portion, a second portion and a passageway therebetween;

a shoulder located in the passageway;

the shoulder adapted to receive a connector so that in use, a head of the connector abuts against a part of the shoulder, and a body of the connector passes through a bore formed by the shoulder to engage with a dental implant to secure the dental abutment to the dental implant.

A benefit of the dental implant and dental prosthesis assembly system is that the use of the dental abutment improves stress management and load distribution through the prosthesis and dental implant by absorbing stresses and strains transferred to the prosthesis and dental implant through the motion of chewing. The dental implant and dental prosthesis assembly system improves dental implant survival rate due to improved stress management and load distribution through the dental implant which can reduce bone loss around the implant, a known source of implant failure. Furthermore, the dental abutment may improve prosthetic survival rates due to improved strass management. The dental implant and dental prosthesis assembly system improves dental implant survival rate since improved shock absorption, stress management and load distribution through the dental implant due to the dental abutment can reduce the level of bone loss observed around the implant and improve bone level maintenance. Excessive bone loss around the implant can lead to biological and mechanical complications and implant failure. A further benefit of the dental implant and dental prosthesis assembly system is improved patient comfort and reduced pain. The improved dampening of the occlusal forces by the dental implant and dental prosthesis assembly system behave as a stress breaker which is important for implant preservation and patient comfort. Vertical chewing forces are absorbed by the dental implant and dental prosthesis assembly system and redistributed into a range of orientations. The benefit of this absorption and redistribution of vertical chewing forces is that stress is transferred to the bone around the implant for effectively and over a larger surface area which appears to artificially simulate the behaviour of periodontal ligaments. Periodontal ligaments, which are typically lost during placement of the dental are a group of specialised connective tissue fibres that attach a tooth to the alveolar bone within which it sits. Implant design aims to address the loss of periodontal ligaments to reduce bone resorption around the implant, therefore with the use of the dental implant and dental prosthesis assembly system described above, new implant designs become possible which more efficiently mimic the behaviour of the lost periodontal ligament.

Optionally, the dental implant has a cross sectional diameter of 7 mm or less, more preferably, 5 mm or less, or 3 mm or less. Optionally, the dental implant has a cross sectional diameter of 1.0 mm to 7.0 mm. More preferably, the dental implant has a cross sectional diameter of 3 mm to 5 mm and more preferably, from 1.8 mm to 3.0m and more preferably from 1.8 mm to less than 3 mm. Optionally, the dental implant has a length of 3 mm to 55 mm, more preferably from 5 mm to 20 mm and most preferably, from 6 mm to 14 mm, or from 5 mm to 6 mm or less than 6 mm. Optionally, the dental is formed of a metal, ceramic or a polymeric material. A further benefit of the a dental implant and dental prosthesis assembly system is that it enables the use of smaller diameter dental implants and shorter dental implants because of the improved stress management and load bearing capabilities of the dental abutment. Typically, smaller diameter dental implants have been prone to cause increased bone loss and experience poor implant survival rates. However, the Applicants have found that the use of the assembly system reduces the stress received by the implants during chewing and enables the use of smaller diameter dental implants and shorter dental implants because the dental implants are subjected to less stress. The assembly system absorbs a proportion of the stresses transferred to the prosthesis and effectively shields the dental implant from high stresses.

The dental prosthesis may be formed of a metal, ceramic or a polymeric material. Preferably, the dental prosthesis is formed from a polymeric material. A further benefit of the polymeric dental prosthesis is that stress adsorption and redistribution through the entire dental implant and dental prosthesis assembly system is improved.

The dental prosthesis may be secured to the dental abutment with a screw or an adhesive or a cement.

In an example, the dental prosthesis and the dental abutment may be formed in a single piece. Optionally, the dental prosthesis comprises a plurality of prostheses. Optionally, the system provides a plurality of dental implants, wherein each dental implant is provided with a dental abutment and a prosthesis.

A further benefit of the dental abutment of the dental implant and dental prosthesis assembly system is that the dental abutment improves stress management and load distribution through the dental implant by absorbing stresses and strains transferred to the dental implant through the motion of chewing. The dental abutment improves dental implant survival rate since improved stress management and load distribution through the dental implant can reduce bone loss around the implant which can lead to implant failure. Furthermore, the dental abutment improves prosthetic survival rates due to improved stress management through the dental implant and dental prosthesis assembly system. Optionally, the passageway extends from a first end to a second end. Optionally, the shoulder extends inwardly from a surface of the passageway so that the shoulder forms a bore configured to receive the connector so that in use, the connector abuts against the shoulder and passes through the bore to engage with a gingival end of a dental implant so that the gingival end of the dental implant abuts against the shoulder to secure the dental abutment to the dental implant.

Optionally, the head of the connector is at least partially retained in the first portion of the body. More preferably, the first end, the shoulder and at least a portion of the passageway define a first recess configured to accommodate or at least partially accommodate the head of the connector.

Optionally, the first end of the dental abutment is configured to directly support a dental prosthesis.

Optionally, the passageway is substantially cylindrical. Preferably, the opposing surfaces of the passageway are substantially parallel. Preferably, the passageway has a longitudinal axis extending from a first end of the dental abutment to a second end of the dental abutment.

Optionally, the shoulder is integrally formed in the body. Optionally, the shoulder extends inwardly substantially in a direction perpendicular to the longitudinal axis of the passageway. Optionally, the shoulder extends inwardly at an angle from 40 degrees to 50 degrees to the longitudinal axis of the passageway. Optionally, the first recess is configured to receive a portion of the dental prosthesis. Optionally, the shoulder extends continually around the circumference of the passageway to form an annulus.

Optionally, the shoulder is located partway along a length of the passageway to define a first recess at the first end of the dental abutment and a second recess at the second end of the dental abutment. The second recess may be configured to receive a portion of the dental implant to stabilise the abutment on the dental implant.

Optionally, the shoulder is located approximately halfway between the first end and the second end. Optionally, the shoulder is located from approximately one third to two thirds of the length of the passageway from the first end. Optionally, the shoulder is located at the second end of the body. Optionally, the shoulder has a thickness of around 0.5 mm to 3 mm. More preferably, the shoulder has a thickness of 1 mm to 2 mm or 1 mm or more. Preferably, at least a portion of the shoulder has a thickness of around 0.5 mm to 3 mm and more preferably of around 1 mm or more. Optionally, the shoulder has a length extending from the passageway of 0.5 mm to 2 mm, and more preferably, a length of 1 mm or more.

Preferably, the overall height of the dental abutment from the first end to the second end is from 3 mm to 5 mm. Optionally the shoulder forms a central bore coaxial to the axis of the passageway. In another example, the bore may be offset from the axis of the passageway. Optionally, the bore is cylindrical and/or the opposing walls of the bore are substantially parallel. Optionally, the bore is conical. Optionally, the first recess has conical walls. Optionally, the wall of the bore is threaded to engage with complementary threads on a surface of a shaft of the connector. Preferably, the threaded wall is configured such that rotation of the connector around the axis of the passageway drives the threaded connector through the bore.

Optionally, the distance between the inner wall of the passageway and the outer wall of the dental abutment (i.e. the thickness of the wall) is 0.5 mm to 2 mm. More preferably, the distance between the inner wall of the passageway and the outer wall of the dental abutment is from 0.5 mm to 5 mm, or from 1 mm to 2 mm, or from 1 mm or more.

Optionally, the dental abutment is configured such that the dental prosthesis is fabricated around an upper portion of the abutment.

The polymeric material preferably comprises a repeat unit of formula (I):

wherein t1 and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2.

The composition, may consist or consist essentially of the polymeric material, or may include, for instance from 60 to 100%, say from 75 to 100% of the polymeric material, with from 0 to 40%, say from 0 to 25% of other materials. The composition may include, for example colourants (e.g. pigments, ceramics, metal oxides (e.g. titanium dioxide)) or fillers (for example reinforcing or wear enhancing fillers or fibres, bioactive fillers such as bioglasses, soluble glasses, zeolites containing antibacterial agents such as silver ions, nanosilver, ceramics such as hydroxyapatite (HA) or substituted HA or treatment agents such as antibiotic doped HA or compounds favourable to the gingiva, diagnostic agents such as radiopaque fillers such as barium sulphate, aesthetic fillers such as reflective agents and light refracting agents, fillers conveying some taste or flavour altering or enhancing effect or breath freshening effect). The composition may include, for instance, 0-10 wt%, suitably 0-6 wt% of colourants. Colourants may be selected so the composition is white. The composition may include, for instance, 0-20 wt%, suitably 0-10 wt% of colourants. Colorants compounded with the polymer enable a range of dental relevant coloration, for example but not restrictive to white, tooth and dentin colour, bone colour, pink, gum and gingiva colour.

Colourants may be employed so that the colour is graduated. In one embodiment, the composition includes no colourant. When a filler is included in the composition, it may suitably be included to improve the mechanical properties and/or bonding characteristics and/or biological acceptability of the composition. However, it has been found that cores for tooth prostheses with excellent mechanical properties can be made without requiring addition of filler. Preferably, the composition comprises at least 80 wt%, at least 90 wt% or at least 94 wt% of the polymeric material. The polymeric material may be the same polymeric material for each of the first and second portions, or may be a different polymeric material. Preferably, the same polymeric material such as PEEK homopolymer is used as polymeric material in each of the first and second portions.

The polymeric material preferably consists essentially of a repeat unit of formula I. Preferred polymeric materials comprise (or consist essentially of) a repeat unit wherein t1 =1 , v1=0 and w1=0; t1=0, v1=0 and w1=0; t1=0, w1=1 , v1=2; or t1=0, v1 =1 and w1=0. More preferred polymeric materials comprise (or consist essentially of) a repeat unit wherein t1 =1 , v1=0 and w1=0; or t1=0, v1 =0 and w1 =0. The most preferred polymeric material comprises (or consists essentially of) a repeat unit wherein t1 =1 , v1 =0 and w1 =0: in other words a homopolymeric polyetheretherketone.

In preferred embodiments, the polymeric material is selected from polyetheretherketone, polyetherketone, polyetherketoneetherketoneketone and polyetherketoneketone. In a more preferred embodiment, the polymeric material is selected from polyetherketone and polyetheretherketone. In another preferred embodiment, the polymeric material is polyetheretherketone such as a homopolymer polyetheretherketone. The polymeric material may have a Notched Izod Impact Strength (specimen 80mm x 10mm x 4mm with a cut 0.25mm notch (Type A), tested at 23°C, in accordance with IS0180) of at least 3KJm ^-2 , preferably at least 4KJm ^-2 , more preferably at least 4.5KJm ^-2 . The Notched Izod Impact Strength may be less than 10KJrrf ² , suitably less than 8KJm ^-2 . The Notched Izod Impact Strength may be at least 3KJm ^-2 , suitably at least 3.5KJm ^-2 , preferably at least 4KJm ^-2 . The impact strength may be less than 50 KJrrf ² , suitably less than 30KJm ^"2 .

The polymeric material suitably has a melt viscosity (MV) of at least 0.06 kNsrrf ² , preferably has a MV of at least 0.09 kNsrrf ² , more preferably at least 0.12 kNsrrf ² , or at least 0.15 kNsrrf ² . Advantageously, the MV may be at least 0.30 kNsrrf ² and/or at least 0.35 kNsrrf ² . An MV of 0.4 kNsrrf ² has been found to be particularly advantageous in the manufacture of accurate, strong dental prosthetics. MV is suitably measured using capillary rheometry operating at 400°C at a shear rate of 1000S-1 using a cylindrical tungsten carbide die, 0.5mmx3.175mm (diameter x length of die). The polymeric material may have a MV of less than 1.00 kNsm-2, preferably less than 0.5 kNsm-2. The polymeric material may have a MV in the range 0.09 to 0.5 kNsm-2, preferably in the range 0.14 to 0.5 kNsm-2, more preferably in the range 0.4 to 0.5 kNsm- 2.

The polymeric material may have a tensile strength, measured in accordance with IS0527 (specimen type 1 b) tested at 23°C at a rate of 50mm/minute of at least 20 MPa, preferably at least 60 MPa, more preferably at least 80 MPa. The tensile strength is preferably in the range 80-110 MPa, more preferably in the range 80-100 MPa.

The polymeric material may have a flexural strength, measured in accordance with IS0178 (80mm x 10mm x 4mm specimen, tested in three-point-bend at 23°C at a rate of 2mm/minute) of at least 50 MPa, preferably at least 100 MPa, more preferably at least 145 MPa. The flexural strength is preferably in the range 145-180M Pa, more preferably in the range 145-164 MPa.

The polymeric material may have a flexural modulus, measured in accordance with IS0178 (80mm x 10mm x 4mm specimen, tested in three-point-bend at 23°C at a rate of 2mm/minute) of at least 1 GPa, suitably at least 2 GPa, preferably at least 3 GPa, more preferably at least 3.5 GPa. The flexural modulus is preferably in the range 3.5-4.5 GPa, more preferably in the range 3.5-4.1 GPa. The polymeric material may be amorphous or semi-crystalline. It is preferably crystallisable. It is preferably semi-crystalline. The level and extent of crystallinity in a polymer is preferably measured by wide angle X-ray diffraction (also referred to as Wide Angle X-ray Scattering or WAXS), for example as described by Blundell and Osborn (Polymer 24, 953, 1983). Alternatively, crystallinity may be assessed by Differential Scanning Calorimetry (DSC).

The level of crystallinity of the polymeric material may be at least 1 %, suitably at least 3%, preferably at least 5% and more preferably at least 10%. In or preferred embodiments, the crystallinity may be greater than 25%. It may be less than 50% or less than 40%. Preferably the prosthodontic device includes a framework having the aforementioned levels of crystallinity.

The main peak of the melting endotherm (Tm) of the polymeric material (if crystalline) may be at least 300°C.

For the polymeric material, it is preferred that t1 =1 , v1 =0 and w1 =0.

According to a second aspect, there is disclosed a dental abutment formed from a composition comprising or consisting of a polymeric material, the dental abutment comprising:

a body having a first portion, a second portion and a passageway therebetween,

a shoulder located in the passageway

the shoulder adapted to receive a connector so that in use, a head of the connector abuts against a part of the shoulder, and a body of the connector passes through a bore formed by the shoulder to engage with a dental implant to secure the dental abutment to the dental implant. The polymeric material preferably comprises a repeat unit of formula (I): wherein t1 and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2. The polymeric material may have the same characteristics as described in reference to the polymer material according to the first aspect. Optionally, the passageway extends from a first end to a second end.

Optionally, the shoulder extends inwardly from a surface of the passageway so that the shoulder forms a bore configured to receive the connector so that in use, the connector abuts against the shoulder and passes through the bore to engage with a gingival end of a dental implant so that the gingival end of the dental implant abuts against the shoulder to secure the dental abutment to the dental implant.

Optionally, the head of the connector is at least partially retained in the first portion of the body. More preferably, the first end, the shoulder and at least a portion of the passageway define a first recess configured to accommodate or at least partially accommodate the head of the connector.

Optionally, the first end of the dental abutment is configured to directly support a dental prosthesis.

Optionally, the passageway is substantially cylindrical. Preferably, the opposing surfaces of the passageway are substantially parallel. Preferably, the passageway has a longitudinal axis extending from a first end of the dental abutment to a second end of the dental abutment. Optionally, the shoulder is integrally formed in the body. Optionally, the shoulder extends inwardly substantially in a direction perpendicular to the longitudinal axis of the passageway. Optionally, the shoulder extends inwardly at an angle from 40 degrees to 50 degrees to the longitudinal axis of the passageway. Optionally, the first recess is configured to receive a portion of the dental prosthesis. Optionally, the shoulder extends continually around the circumference of the passageway to form an annulus.

Optionally, the shoulder is located partway along a length of the passageway to define a first recess at the first end of the dental abutment and a second recess at the second end of the dental abutment. The second recess may be configured to receive a portion of the dental implant to stabilise the abutment on the dental implant.

Optionally, the shoulder is located approximately halfway between the first end and the second end. Optionally, the shoulder is located from approximately one third to two thirds of the length of the passageway from the first end. Optionally, the shoulder is located at the second end of the body. Optionally, the shoulder has a thickness of around 0.5 mm to 2 mm. More preferably, the shoulder has a thickness of 1 mm or more. Preferably, at least a portion of the shoulder has a thickness of around 0.5 mm to 2 mm and more preferably of around 1 mm or more. Optionally, the shoulder has a length extending from the passageway of 0.5 mm to 2 mm, and more preferably, a length of 1 mm or more. Preferably, the overall height of the dental abutment from the first end to the second end is from 3 mm to 5mm. Optionally the shoulder forms a central bore coaxial to the axis of the passageway. In another example, the bore may be offset from the axis of the passageway. Optionally, the bore is cylindrical and/or the opposing walls of the bore are substantially parallel. Optionally, the bore is conical. Optionally, the first recess has conical walls. Optionally, the wall of the bore is threaded to engage with complementary threads on a surface of a shaft of the connector.

Preferably, the threaded wall is configured such that rotation of the connector around the axis of the passageway drives the threaded connector through the bore.

Optionally, the distance between the inner wall of the passageway and the outer wall of the dental abutment (i.e. the thickness of the wall) is 0.5 mm to 2 mm. More preferably, the distance between the inner wall of the passageway and the outer wall of the dental abutment is from 0.5 mm to 5 mm, or from 1 mm to 2 mm, or from 1 mm or more.

Preferably, the shoulder protrudes from the surface of the passageway substantially normal to the plane of the surface.

Optionally, the dental abutment is configured such that the dental prosthesis is fabricated around an upper portion of the abutment. In a third aspect, there is disclosed a kit comprising a dental abutment as described. The kit may further comprise a dental implant. Preferably, the dental abutment and/or the dental implant are provided in a receptacle in a sterile state.

In a fourth aspect, there is disclosed a method for assembling a dental implant assembly system, the method comprising:

(i) selecting a dental abutment as described in the first aspect;

(ii) selecting a connector;

(iii) inserting said connector into a first end of the dental abutment and through a bore of the dental abutment and engaging the connector with a gingival portion of a dental implant fixed in a bone of a jaw in a human or animal body, wherein the gingival portion is exposed through the bone, and fixing the dental abutment. Optionally, the method further provides building a dental prosthesis around the first end of the dental abutment or affixing a dental prosthesis to the first end of the dental abutment.

Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

Figure 1 illustrates a cross sectional view of an example of a dental abutment; Figure 2 illustrates a cross sectional view of a dental implant and dental prosthesis system;

Figure 3 illustrates a cross sectional view of a dental abutment and dental implant; Figure 4 illustrates several examples of dental implant and dental prosthesis systems;

Figure 5 illustrates examples of dental implant and dental prosthesis systems; Figure 6 illustrates a dental implant and dental prosthesis system;

Figure 7 illustrates a dental implant and dental prosthesis system;

Figure 8 illustrates another example of a dental implant and dental prosthesis system;

Figure 9 illustrates a further example of a dental implant and dental prosthesis system;

Figure 10 illustrates a dental implant and dental prosthesis system; and

Figure 11 illustrates a dental implant and dental prosthesis system.

In the drawings like reference numerals refer to like parts.

DETAILED DESCRIPTION

The dental implant and dental abutment assembly system is shown in the following Figures. Figure 1 shows an exemplary embodiment of a dental abutment 10 formed from a polymeric material. Dental abutments 10 in accordance with the invention are preferably polymeric abutments having a composition consisting of polyetheretherketone (PEEK) polymer, preferably, PEEK-OPTIMA ™ of melt viscosity (MV) 0.45kNsm-2 , simply referred to hereinafter as PEEK. Preferably still, the PEEK polymeric prostheses are formed from a JUVORA™ Dental Disc made from said PEEK-OPTIMA™.

Figure 1 shows a cross section through the dental abutment 10. The dental abutment 10 has a body having a first portion 16, a second portion 18 and a passageway 12 extending between the first portion 16 and the second portion 18. The dental abutment 10 also has a shoulder 20 located in the passageway 12. The shoulder 20 is adapted to receive a connector 40 (shown in Figure 2) so that in use, a head 42 of the connector 40 abuts against a part of the shoulder 12, and a body 44 of the connector 40 passes through a bore 30 formed by the shoulder 12 to engage with a dental implant 50 (shown in Figure 2) to secure the dental abutment 10 to the dental implant.50. The passageway 12 has a surface or inner wall 14. The shoulder 20 is a shelf like feature extending inwardly from the inner wall 14 of the passageway 12 towards a longitudinal axis (A) of the passageway 12. In one example, the shoulder 20 extends continually around the inside (inner) wall 14, and in an alternative example the shoulder is formed in discrete sections. The shoulder 20 extends towards the central longitudinal axis (A) of the passageway 12 but does not reach the central axis of the passageway 12 so that tip or lip of the shoulder 20 forms a bore 30. The shoulder has a first side 22, and a second side 24, and an end portion 26. The end portion 26 of the shoulder 20 forms the inner wall of the bore 30. The shoulder 20 extends from the passageway 12 substantially perpendicular to the longitudinal axis (A) of the passageway. A benefit of this arrangement is that the shoulder 20 provides a substantial bearing surface 22 to retain the head 42 of the connector. By providing a substantially flat surface in which the head 42 of the connector 40 abuts, improved stress absorption is achieved between a dental prosthesis and the dental implant 50. Improved stress management between the dental prosthesis and the dental implant reduces the risk of implant failure.

The bore 30 is configured to receive a connector 40 as shown in Figure 2. The connector is a screw or a bolt or other similar connector. In use, a connector 40 is inserted into the dental abutment 10 through the first end 16 and into the passageway 12. The connector then passes through the bore 30 and is retained by the shoulder 20 such that a head 42 or retainer portion of the connector 40 abuts against the first side 22 of the shoulder 20. The connector body or shaft portion 44 of the connector 40 passes through the bore 20 to engage with a gingival end 52 of a dental implant 50 so that the gingival end 52 of the dental implant 50 is drawn towards the dental abutment 10 and abuts against the second side 24 of the shoulder 20 to secure the dental abutment 10 to the dental implant 50. The first end 16, the shoulder 20 and at least a portion of the passageway 12 form a first recess 18 which is able to accommodate a head 42 of the connector 40. The first end 16 of the dental abutment 10 is configured to support a dental prosthesis 60 as shown in Figures 4 and 5. Dental abutments 10 of the present invention may be machined from a block of material, for example a polymeric block, by computer aided milling, with the specific geometry of the dental abutment in dependence upon data collated using digital technology and in relation to the intended recipient of said dental abutment 10. As such the outer dimensions and shape of the dental abutment are dependent on the requirements of the recipient.

A benefit of the dental abutment is that it improves stress management and load distribution through the dental implant by absorbing stresses and strains transferred to the dental implant through the motion of chewing. Polymeric materials such as PEEK polymer have an elastic modulus (GPa) closer to the elastic modulus of natural bone and considerably lower than other known materials used in dental prostheses. For example, the elastic modulus of PEEK-OPTIMA™ is 4.1 GPa, whereas the elastic modulus of titanium is 1 10 GPa. By using a dental abutment of the present invention, the survival rates of dental implants can be improved by improving stress management and load distribution through the dental implant because the dental abutment is able to absorb stress more effectively. Furthermore, using a dental abutment of the present invention can reduce bone loss around the implant, and bone loss has been found to cause implant failure. Furthermore, the dental abutment improves prosthetic survival rates due to improved strass management.

In an example, the passageway 12 is substantially cylindrical. The inner wall 14 of the passageway 12 is substantially smooth. In another example, opposing surfaces of the passageway 12 are substantially parallel. The shoulder 20 provides a means for securing the abutment 10 to the dental implant 50. The shoulder 20 is like a shelf or protrusion extending from the surface 14 of the passageway 12. The shoulder 20 extends inwardly substantially in a direction normal to the surface 14 of the passageway 12. In one example, the shoulder 20 has a thickness of 1 mm or more. Alternatively, the shoulder 20 has at least a portion having a thickness of 1 mm or more. In one example, all portions of the shoulder 20 have a thickness of 1 mm or more. The shoulder 20 has a length as measured from the surface 14 of the passageway 12 to a wall 32 of the bore 30 of 1 mm or more.

In one example, the shoulder forms a central bore 30 coaxial to the axis A of the passageway 12. In another example, the bore 30 may be offset from the axis A of the passageway 12. In another example, the wall 32 of the bore 30 is threaded to engage with complementary threads on a surface of the shaft portion 44 of the connector 40. The threaded wall may be configured such that rotation of connector 40 around the axis of the passageway 12 drives the threaded connector 40 through the bore 30.

Figure 2 shows an example whereby the shoulder 20 located partway along a length of the passageway 12 to define a first recess 17 at the first end 16 of the dental abutment and a second recess 19 at the second end 18 of the dental abutment 10. The second recess 19 is configured to receive a portion of the dental implant 50 to stabilise the abutment 10 on the dental implant 50.

Figure 3 shows a typical example of a dental abutment where the distance 15 between the inner wall 14 of the passageway 12 and the outer wall 14' of the dental abutment 10 (i.e. the thickness of the wall) is 1 mm or more. The shoulder thickness 23 is 1 mm or more.

Figure 4 shows examples of the dental implant and dental prosthesis assembly system. The dental implant and dental prosthesis assembly system includes a dental implant 50 having a gingival end 52 and an implantable end 54 and a dental prosthesis 60. The dental abutment 10 is as described above.

A benefit of the a dental implant and dental prosthesis assembly system is that the use of the dental abutment improves stress management and load distribution through the prosthesis and dental implant by absorbing stresses and strains transferred to the prosthesis and dental implant through the motion of chewing. The dental abutment may improve dental implant survival rate since improved stress management and load distribution through the dental implant can reduce bone loss around the implant which can lead to implant failure. Furthermore, the dental abutment may improve prosthetic survival rates due to improved strass management. Using a dental abutment 10 allows the selection of smaller dental implants 50. The dental abutment 10 allows the use of either a smaller diameter dental implant 50 as shown in Figure 4a or a shorter dental implant 50 as shown in Figure 4b. For example, the dental implant 50 shown in Figure 4a has a cross sectional diameter d of 3 mm or less. This allows for minimal bone removal from the jaw while implanting the dental implant. In one example, d ranges from 1.8 mm to 3.0 mm. Figure 4b shows shorter dental implants 50. In this example, the dental implant has a length of 5 mm to 10 mm, or from 5 mm to 6 mm or less than 6 mm. Figure 5 also illustrates examples of dental implant and dental prosthesis systems. Figure 5a shows a known example, wherein a metal dental abutment is used necessitating the use of a larger diameter dental implant and a longer dental implant. Figures 5b and 5c show benefit of using a dental abutment 10 according to the present invention and how this impacts the relative dimensions required for the dental implant 50.

Figure 6 illustrates a dental implant and dental prosthesis system wherein the dental prosthesis 60 and the dental abutment 10 are formed as a single piece. The dental implant 50 sits within the second recess 19 of the dental abutment 10. The dental prostheses and the dental implant are secured by the use of a metal screw 30. The wall between the metal screw head 30 and the top of the dental implant 50, has a thickness of at least 1 mm.

Figure 7 illustrates a dental implant and dental prosthesis system wherein the dental prosthesis 60 is fixed around or built onto the dental abutment 10. The dental abutment 10 can be secured to the dental prosthesis 60 by means of adhesion, for example using dental cements in the wall interface between the two components so that they mechanically lock when securing the screw 30 to the dental implant 50. The dental implant 50 sits within the second recess 19 of the dental abutment 10.

Figure 8 illustrates another example of a dental implant and dental prosthesis system wherein the dental prosthesis 60 is fixed around or built onto the dental abutment 10. The dental implant 50 abuts the second side 24 of the shoulder and therefore does not sit in a second recess of the dental abutment 10.

Figure 9 illustrates a further example of a dental implant and dental prosthesis system wherein the dental prosthesis 60 is cemented onto the dental abutment 10 at a cement line 62 at the wall interface between the two components. The dental implant 50 sits within the second recess 19 of the dental abutment 10.

Figure 10 illustrates an example of the dental implant and dental prosthesis assembly system in use chewing a nut for example. As the jaws move towards each other to chew the nut, vertical forces are transferred through the prosthesis 60 and to the dental implant 50. The dental implant and dental prosthesis assembly system includes a dental abutment 10 which acts to absorb and redistribute the vertical stresses propagated to the dental prosthesis 60. The inset drawing shows an illustration of the stresses transferred through the dental prosthesis 60 to the dental implant 50. The dental abutment 10 scatters the stresses so that the stress is not only felt at the implantable end of the implant 50, but throughout the implant.

A dental implant and dental prosthesis assembly system having a plurality or dental implants 50 and dental prosthesis 60 is shown in Figure 11 wherein the effect is further improved by the plurality of dental prosthesis 60. Vertical stresses absorbed by the dental prosthesis 60 closest to the nut are transferred through the neighbouring prostheses 60 and through the second dental implant 50, being further scattered by the second dental abutment 10.

The dental abutment is manufactured via injection moulding or CAD/CAM milling.

It will be clear to a person skilled in the art that features described in relation to any of the embodiments described above can be applicable interchangeably between the different embodiments. The embodiments described above are examples to illustrate various features of the invention. Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.