GB2523004A

GB2523004A - Polyaryletherketone prosthodontics device in the form of an inlay or onlay

Info

Publication number: GB2523004A
Application number: GB1500361.9A
Authority: GB
Inventors: Marcus Jarman-Smith; Nuno Sereno; Reinhard Lobenhofer
Original assignee: Juvora Ltd
Current assignee: Juvora Ltd
Priority date: 2014-01-09
Filing date: 2015-01-09
Publication date: 2015-08-12
Also published as: GB201500361D0; GB201400370D0; WO2015104558A1

Abstract

A method of making a prosthodontics device such as an inlay or onlay for tooth fillings or restoration comprises assessing a cavity 4,22 of a tooth 2,20 which is to be provided with the inlay 6 with flat shapeless surface 8 or the onlay 24 with cusps 26 and making an inlay or onlay from a polymeric material such as polyetheretherketone (PEEK)which is shaped to fit within the cavity and adhesively secured within the cavity.

Description

POLYARYLETHERKETONE PROSTHODONTICS DEVICE IN THE FORM

OF AN INLAY OR ONLAY

The invention relates to a prosthodontics device and particularly, although not exclusively, relates to such a device in the form of an inlay or onlay.

Inlays are indirect tooth restorations (fillings) consisting of solid substances (e.g. gold, porcelain or cured composite resins) which are filled in a tooth cavity and cemented in place.

An onlay is the same as an inlay except that it additionally extends to replace a tooth cusp.

Known prosthodontics devices of the types described suffer various disadvantages. For example, composite resins may leach acid (or other undesirable materials) during curing, which can provoke pain in a patient. Furthermore, such resins may undergo shrinkage during curing which may cause small gaps to form between a tooth cavity and the resin. Porcelain devices may be very hard, making their preparation difficult, time-consuming and/or expensive. In addition, an exposed porcelain surface (e.g. cusp) may cause increased wear on an opposing tooth which it may contact, leading to potential wear on the opposing tooth.

Gold is very expensive. Amalgam or other non-precious metals when used can induce issues associated with metal ion release (e.g. metal allergies).

It is an object of present invention to address the above described problems.

According to a Frst aspect of the invention, there is provided a method of making a prosthodontics device, for example, an inlay or onlay, the method comprising the steps of: (i) assessing a cavity which is to be provided with a prosthodontics device; (H) making a prosthodontics device which is shaped to fit within the cavity; wherein said prosthodontics device comprises a polymeric material which comprises a repeat unit of formula (I) (I) where ti and wi independently represent 0 or I and vi represents 0, 1 or2.

Said polymeric material preferably consists essentially of a repeat unit of formula I. Preferred polymeric materials comprise (especially consist essentially of) a said repeat unit wherein tl=1, v10 and wl=0; tl=0, vl=0 and w10; tl=0, wl=1 and vl=2; ortl=0, vl=1 and wl=0. More preferred comprise (especially consist essentially of) a said repeat unit wherein tl=1, vl=0 and w10; or tl=0, vl=0 and wl=0. The most preferred comprises (especially consists essentially of) a said repeat unitwherein tl=1, vl=0 and wl=0.

In preferred embodiments, said polymeric material is selected from polyetheretherketone, polyetherketone, polyetherketoneetherketoneketone and polyetherketoneketone. In a more preferred embodiment, said polymeric material is selected from polyetherketone and polyetheretherketone. In an especially preferred embodiment, said polymeric material is polyetheretherketone.

Said 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 150180) of at least 4KJm2, preferably at least 5KJm2, more preferably at least 6KJm2. Said Notched Izod Impact Strength, measured as aforesaid, may be less than 10KJm2, suitably less than 8KJm2. The Notched Izod Impact Strength, measured as aforesaid, may be at least 3KJm2, suitably at least 4KJm2, preferably at least 5KJm2. Said impact strength may be less than 50 KJm2, suitably less than 30KJm2.

Said polymeric material suitably has a melt viscosity (M of at least 0.06 kNsm2, preferably has a MV of at least 0.09 kNsm2, more preferably at least 0.12 kNsm2, especially at least 0.15 kNsm2. Advantageously, the MV may be at least 0.35 kNsm2 and especially at least 0.40 kNsm2.

MV is suitably measured using capillary rheometry operating at 400°C at a shear rate of 1000s1 using a tungsten carbide die, 0.Smmx3.175mm.

Said polymeric material may have a MV of less than 1.00 kNsm2, preferably less than 0.5 kNsm2.

Said polymeric material may have a MV in the range 0.09 to 0.5 kNsm2, preferably in the range 0.14 to 0.5 kNsm2, more preferably in the range 0.4 to 0.5 kNsm2.

Said polymeric material may have a tensile strength, measured in accordance with 1S0527 (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 80-1 00 MPa.

Said polymeric material may have a flexural strength, measured in accordance with 150178 (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 MPa. The flexural strength is preferably in the range 145-18OMPa, more preferably in the range 145-1 64 MPa.

Said polymeric material may have a flexural modulus, measured in accordance with 1S0178 (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.

Said 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 may be 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 said polymeric material (suitably measured by DSC) may be at least 1%, suitably at least 3%, preferably at least 5% and more preferably at least 10%. In especially preferred embodiments, the crystallinity may be greater than 25%. It may be less than 50% or less than 40%.

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

Said device may comprise (preferably consist essentially of) a composition which comprises said polymeric material. Said composition suitably includes at least 90 wt%, preferably at least 95 wt%, more preferably at least 99 wt% of said polymeric material (especially polyetheretherketone). The balance of the composition may include one or more fillers, for example colourants. Said composition suitably includes less than 5 wt%, preferably less than 1 wt%, more preferably 0 wt% hydroxyapatite. Said composition preferably includes substantially no metal.

Said device is preferably substantially metal-free.

Said device is preferably an insert for a tooth cavity, for example an inlay for a tooth cavity or an onlay for a tooth cavity.

Said insert is preferably shaped in the method so it can fit snugly in the cavity.

Preferably, the shape of the insert (in regions thereof which are to face and/or abut walls which define the cavity) substantially corresponds to the shape defined by walls which define the cavity. Said insert preferably has an irregular shape. Said insert is preferably not symmetrical about any plane.

Said insert preferably includes a first wall which has an irregular shape; it is suitably arranged to fit within and face a wall which defines the cavity. The shape of the first wall preferably corresponds at least in part (preferably substantially entirely) to the shape of the wall which defines the cavity (i.e. at least part, preferably substantially the entirety of, said first wall, has substantially the same shape as that of the cavity). Said insert preferably includes a second wall which suitably is arranged not to face a wall which defines the cavity. Said second wall may be arranged to define an outer surface (e.g. a bite surface) of a tooth which includes the cavity. When said insert is an inlay, the outer surface defined by the second wall may be substantially flat and/or shapeless and/or is not arranged to define a natural-looking surface of a tooth. When, however, said surface is an onlay, the outer surface defined by said second wall may include cusps and/or is shaped to define a natural-looking surface of a tooth.

In step (ii) of the method, said cavity is suitably assessed so as to determine its shape and dimensions so that a said prosthodontics device can be made which can fit into the cavity.

Step (i) may comprise using digital technology to determine the shape and dimensions of said cavity or a model of the cavity may be made, for example by making a cast of the cavity and/or part of a patient's mouth which includes the cavity.

In step (ii), the device may be made by machining, casting, pressing or moulding a sample of said polymeric material. In a preferred embodiment, said device is made by machining. In this case, step (ii) of the method may include the steps of: (a) selecting a blank from which the device can be machined, wherein said blank comprises a polymeric material or a composition as described; (b) using digital technology to collate data to define the shape and/or dimensions of the device; and (c) machining the blank in dependence upon the data.

Step (b) preferably includes scanning the cavity or scanning of a model of a cavity. Step (b) may comprise use of Computer-aided design (CAD) technology.

The method may include a step prior to step (b) of taking an impression of a patient's mouth. The impression may be used to collate said data.

The method preferably involves a CAD/CAM technique whereby data is collated as aforesaid and computer-aided manufacture (CAM) is undertaken in step (c). Thus, in step c), a computer suitably controls the machining of the blank.

Preferably, the selected blank is positioned in a CAD/CAM machine and the machine is arranged to machine the blank in dependence upon the data.

Preferably, machining of said blank is undertaken using at least 5-axis machining, suitably under computer control. In some cases, higher axis (e.g. 7-axis) machining may be undertaken. Machining in step (c) suitably comprises milling. The work piece is suitably cooled during machining so as to control crystallinity of the machined blank.

The method preferably includes the step of adjusting the Ra of a surface of a precursor of said device in order to define said device for fitment in said cavity. Adjusting the Ra may comprise a grit blasting process. Such a process suitably utilises particulate material which becomes embedded in the precursor. Such particulate material may comprise Si02 and/or A1203 Said device preferably has, suitably immediately before fitting in said cavity, a Ra from 0.06 to 7.0 micrometres, where Ra is the roughness average of a surface, expressed in micrometers. This is the arithmetic mean of the absolute departures of a roughness profile from the mean line of a measurement carried out along an arbitrary line along a surface. Ra is suitably measured by a mechanical contact method by means of a stylus drawn in a straight line over the surface with the height of the stylus measured at regular intervals along the surface, wherein the stylus tip has a diameter of 2 micrometres in accordance with DIN EN ISO 4288 and DIN EN ISO 3274, using a Perthometer 5P6 surface profilometer. More preferably, the roughened area may have an Ra from 0.5 to 2.0 micrometres.

In one embodiment, substantially the entirety of said precursor of said device may be treated in order to adjust its Ra as described. Substantially the entirety of said precursor of said device may have a Ra as described. Providing such a device may facilitate bonding of the device in the cavity and/or may facilitate bonding of an optional coating to the device to improve aesthetics of surfaces of the device which are visible in use when the device is positioned in the cavity.

The method may include a step of providing a coating over an area (herein referred to as the or said "exposed area") of the precursor of the device which would otherwise be exposed in use when the device is positioned in a patient's mouth (e.g. when fitted in a cavity).

The exposed area is preferably a surface of the device which faces outwardly in use and/or is an exposed surface of the device in use. It may be a bite surface of a tooth incorporating the device.

Said coating is preferably tooth-coloured. The rest of the device may not be tooth-coloured. It may be the natural colour of said polymeric material.

The method preferably comprises selecting a resin or a resin precursor which is to define said coating and applying, for example using a brush or spatula, said resin or precursor to predetermined areas of the precursor of said device. The resin or precursor may be treated with radiation, suitably to effect polymerisation and/or curing. Said radiation may have a wavelength in the range 350 to SOOnm.

Said coating suitably includes less than 50 wt%, preferably less than 35 wt%, more preferably less than 20 wt%, especially less than 10 wt% of ceramic filler. It may advantageously include less than 5 wt% or substantially zero wt% of ceramic filler. Low (or no) ceramic filler may facilitate the coating being relatively flexible (i.e. non-stifO and/or having a similar elastic modulus to the polymeric material of formula I. Said coating may have a thickness of less than 250 pm (suitably less than 200 pm, preferably less than 150 pm, more preferably less than 100 pm).

Said coating may have a surface area of 2mm2 to 20mm2 and said coating may have a thickness of less than 250 pm (suitably less than 200 pm, preferably less than 150 pm, more preferably less than 100 pm) over said entire surface area.

Said coating preferably has a thickness in the range 10 to 100 pm, preferably over an area of 2mm2 to 200mm2.

According to a second aspect of the invention, there is provided a prosthodontics device, for example an inlay or onlay, made in the method of the first aspect per se.

The invention extends to a prosthodontics device, for example an inlay or onlay per se.

The device may have any feature of the device of the first aspect. The device may be an inlay or onlay comprising said polymeric material, especially a polymeric material which comprises a repeat unit of formula I wherein tl=1, wl=0 and vl=0, forexample polyetheretherketone.

Said device may comprise (preferably consist essentially of) a composition as described according to the first aspect. Said device may be irregular in shape, it may not be symmetrical about any plane. Said device may have a volume in the range 8mm3 to 500mm3, preferably 8mm3 to 250mm3, for example 8mm3 to 150mm3. Said device may have a maximum dimension of less than 10mm, for example less than 8mm.

Said device may include at least part of its surface area (e.g. a part which is to be enclosed by the cavity in use) having a Ra in the range 0.06 to 7.0 micrometers andlor as described according to the first aspect.

Said device may be provided with a coating as described according to the first aspect.

The coating may be tooth-coloured. It may be provided on a surface of the device which faces outwardly in use and/or which is an exposed surface of the device in use, as described according to the first aspect. Coating may be provided on less than 50%, for example less than 25%, of the surface area of the device. Thus, the device preferably includes an area (suitably at least 50% of the total surface area of the device) which is not provided with said coating.

The invention extends to a collocation comprising said prosthodontics device of the second aspect in combination with information relating to the shape of a cavity in which the device may be fitted or in combination with information relating to a patient having a cavity into which the device may be fitted.

The collocation may include said device, for example an inlay or onlay, provided in a package, for example a receptacle, in combination with information sufficient to identify a patient having a cavity into which the device may be fitted.

According to a third aspect of the invention, there is provided a method of fitting a prosthodontics device, for example an inlay or onlay in a cavity, the method comprising: (i) selecting a device which has been made to fit in the cavity, for example in a method of the first aspect or being as described in the second aspect; (U) using an adhesive and/or cement to secure the device in the cavity.

B

The device preferably has a Ra as described according to the first and/or second aspects.

Suitably, the shape and/or size of the device selected in step (i) is substantially identical to the shape and/or size of the device when secured in the cavity. That is, the shape of the device is preferably not changed and/or distorted during or after positioning in the cavity.

Any invention described herein may be combined with any feature of any other invention described herein mutatis mutandis.

Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure lisa cross-section through a tooth showing an inlay for fitment in a cavity in the tooth; and Figure 2 is a cross-section through a tooth showing an onlay for fitment in a cavity in the tooth.

The following material is referred to hereinafter: PEEK -refers to PEEK-OPTIMA grades LTI, LT2 or LT3 having melt-viscosities in the range 0.16 to 0.44 KNsm2, obtained from lnvibio Ltd. The Rocatec system from 3M ESPE -3M ESPE Rocatec Plus. The Rocatec system is a tribochemical method for silicatising surfaces. Tribochemistry involves creating chemical bonds by applying mechanical energy. This supply of energy may take the form of rubbing, grinding or sandblasting. There is no application of heat or light which would normally be the case with chemical reactions. For this reason the Rocatec system may also be referred to as cold silicatisation because the mechanical energy is transferred to the substrate in the form of kinetic energy and thesilicatisation takes place macroscopically without any change in temperature. In general terms, the Rocatec system consists of a coating unit (Rocatector delta or Rocatec junior), microblasting sand Rocatec Pre (cleaning and activating the surface), coating sand Rocatec Plus or Rocatec Soft and a silane solution (3M ESPE Sil resin primer).

Rocatec Pre -refers to a High-purity aluminium oxide (110 pm).

Rocatec Plus -refers to High-purity aluminium oxide (110 pm), modified with silica (Si02).

3M Rocatec ESPE Sil: Silane in ethanol. The silane used in 3M ESPE Sil is characterised by two molecule ends of different polarity. Alkoxy groups of a silanol unit make a chemical bond with the silicatised surface.

3M ESPE Sinfony Light-Curing composite -refers to a high strength, light-cured, ultra- fine particle composite. The main component of the filler mix in SinfonyTM is a special, ultra-fine strontium aluminium borosilicate glass in the sub-micron range. In addition it contains pyrogenic silica, also known as micro-dispersed silicon dioxide. Additionally, it includes a glass ionomer (5% by wt.). The composite includes a mixture of aliphatic and cycloaliphatic monomers.

Referring to Figure 1, a tooth 2 includes a drilled-out cavity 4 in which an inlay 6, having a generally flat, shapeless surface 8, is arranged to be secured to fill and protect the cavity.

The cavity 4 is formed in a conventional manner. Then a mould is taken of an appropriate part of the patient's mouth which includes the cavity, using a standard impression tray. The mould is then poured with dental plaster and allowed to set. The part of the mould defining the cavity (at least) is scanned to collate relevant CAD data which is input into a 3-axis, preferably a 3+2 axis or a 5-axis CAD-CAM machine. The machine produces the inlay 8 or a precursor of the inlay (which may be finished manually) from a PEEK disc. Thus, the inlay is made wholly from PEEK.

The following steps may then be undertaken to cement the inlay in position: (i) The walls of the cavity 4 are prepared, for example by etching of the enamel surface with a phosphoric acid solution.

(ii) The surfaces of the inlay 8 which are to contact the cavity are roughened, for example using 3M ESPE Rocatec Plus.

Before cementation, the surfaces of the PEEK inlay which are to contact the cavity 4 are roughened (e.g. use 3M ESPE Rocatec) and then coated with a thin unfilled light-curing composite (e.g. Heliobond, Ivoclar Vivadent) which acts as a primer. Then the inlay is adhesively secured in position with a dual curing high viscosity composite cement (e.g. Variolink II, IvoclarVivadent).

The inlay described could be used as manufactured in the machining process described in which case it may be beige in colour (which is the natural colour of PEEK). This may be suitable when the inlay is minimally visible in use. As an alternative, before the inlay is cemented in the cavity 4, it could be veneered, for example using 3M ESPE Sinfony (Trade Mark) opaque and composition.

The inlay can be very strongly secured in position as described. The PEEK material may be advantageous, at least for the following reasons: (i) The inlay can be made with very high precision meaning that substantially no voids will exist between inlay and cavity.

(ii) No acid (or any other) substance will leach from the PEEK inlay, since it does not go through a curing step during its fitment in the cavity.

(iii) The inlay will exhibit minimal shrinkage, expansion or degradation during its life time.

(iv) The inlay may be relatively cheaply manufactured but provide a high quality result.

Referring to Figure 2, a tooth 20 includes a drilled out cavity 22 in which an onlay 24 having cusps 26 is arranged to be secured to fill and protect the cavity. The onlay is generally produced from PEEK following the steps described in relation to the inlay.

However, after machining, the onlay is suitably finished to improve its aesthetics and to cover areas made of PEEK which may otherwise be visible in use. For example, such areas of PEEK may be veneered as follows: (i) Areas to be veneered are sand blasted using 3M ESPE Rocatec Plus (pressure = 3 bar; distance 1cm) to ensure an even rough surface is obtained).

(U) A primer (3M ESPE Rocatec Sil) is applied to the areas and dried.

(iii) An opaque (3M ESPE, Opaque) is applied over the primer and polymerised.

(iv) A dentin veneer (3M ESPE Symphony) is applied over the opaque and polymerised.

The aforementioned steps result in the potentially visible areas of the onlay being coated in a white-coloured tooth-like layer.

After the treatment described, the onlay may be adhesively secured in the cavity as described for the inlay.

The invention is not restricted to the details of the foregoing embodiment(s). 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), orto any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1. A method of making a prosthodontics device, for example an inlay or onlay, the method comprising the steps of: (i) assessing a cavity which is to be provided with a prosthodontics device; (ii) making a prosthodontics device which is shaped to fit within the cavity; wherein said prosthodontics device comprises a polymeric material which comprises a repeat unit of formula (I) (I) where tl and wi independently represent 0 or 1 and vi represents 0, 1 or2.
2. A method according to claim 1, wherein said polymeric material comprises (preferably consists essentially of) said repeat unit wherein U =1, vi =0 and wi =0.
3. A method according to claim 1 or claim 2, wherein said polymeric material is polyetheretherketone.
4. A method according to any preceding claim, wherein said polymeric material has a Melt Viscosity in the range 0.09 to 0.5 kNsm2, preferably in the range 0.4 to 0.5 kNsm2.
5. A method according to any preceding claim, wherein the level of crystallinity of said polymeric material is greater than 25%.
6. A method according to any preceding claim, wherein said device comprises (preferably consists essentially of) a composition which comprises said polymeric material, wherein said composition includes at least 90 wt%, preferably at least 99 wt%, of said polymeric material.
7. A method according to any preceding claim, wherein said device is substantially metal-free.
8. A method according to any preceding claim, wherein said device is an insert for a tooth cavity.
9. A method according to claim 8, wherein the shape of the insert in regions thereof which are to face and/or abut walls which define the cavity substantially corresponds to the shape defined by walls which define the cavity.
10. A method according to claim 8 or claim 9, wherein said insert includes a first wall which has an irregular shape and is arranged to fit within and face a wall which defines the cavity, wherein the shape of the firstwall corresponds at least in part to the shape of the wall which defines the cavity; and said insert includes a second wall which is arranged not to face a wall which defines the cavity, wherein said second wall is arranged to define an outer surface of a tooth which includes the cavity.
11. A method according to any preceding claim wherein, in step (ii) of the method, said cavity is assessed so as to determine its shape and dimensions so that a said prosthodontics device can be made which can fit into the cavity, wherein preferably step (i) comprises using digital technology to determine the shape and dimensions of said cavity or a model of said cavity is made.
12. A method according to any preceding claim wherein, in step (U), the device is made by machining and step (H) of the method includes the steps of (a) selecting a blank from which the device can be machined, wherein said blank comprises a polymeric material or a composition as described; (b) using digital technology to collate data to define the shape andlor dimensions of the device; and (c) machining the blank in dependence upon the data.
13. A method according to claim 12, wherein step (b) includes scanning the cavity or scanning of a model of said cavity.
14. A method according to any preceding claim, wherein machining in step (c) comprises milling and the work piece is cooled during machining so as to control crystallinity of the machined blank.
15. A method according to any preceding claim, wherein the method includes the step of adjusting the Ra of a surface of a precursor of said device in order to define said device for fitment in said cavity.
16. A method according to claim 15, wherein adjusting the Ra comprises a grit blasting process which utilises particulate material which becomes embedded in the precursor.
17. A method according to any preceding claim, wherein said device has, immediately before fitting in said cavity, a Ra from 0.06 to 7.0 micrometres, where Ra is the roughness average of a surface expressed in micrometers.
18. A method according to any of claims 15 to 17, wherein substantially the entirety of said precursor of said device is treated in order to adjust its Ra.
19. A method according to any preceding claim, wherein the method includes a step of providing a coating over an area of a precursor of the device which would otherwise be exposed in use when the device is positioned in a patient's mouth.
20. A method according to claim 19, wherein said coating is tooth-coloured.
21. A method according to claim 19 or claim 20, wherein the method comprises selecting a resin or a resin precursor which is to define said coating and applying said resin or precursor to predetermined areas of the precursor of the device.
22. A method according to any of claims 19 to 21, wherein said coating includes less than 10 wt% of ceramic filler and preferably includes substantially zero wt% of ceramic filler.
23. A method according to any of claims 19 to 22, wherein said coating has a thickness of less than 250 pm.
24. A method according to any of claims 19 to 23, wherein said coating has a thickness in the range 10 to 100 pm over an area of 2mm2 to 200mm2.
25. A prosthodontics device, for example an inlay or onlay, made in the method of any preceding claim.
26. A prosthodontics device which is an inlay or onlay comprising a polymeric material which comprises a repeat unit of formula I of claim 1 wherein t11, w10 and v10, wherein said device is irregular in shape, is not symmetrical about any plane, has a volume in the range 8mm3 to 500mm3, and a maximum dimension of less than 10mm, wherein at least part of its surface area has an Ra in the range 0.06 to 7.0 micrometers, and wherein, preferably, said device is provided with a coating which is tooth-coloured.
27. A collocation comprising a prosthodontics device according to claim 25 or claim 26 in combination with information relating to the shape of a cavity in which the device may be fitted or in combination with information relating to a patient having a cavity into which the device may be fitted.
28. A collocation according to claim 27, wherein said device, for example said inlay or onlay, is provided in a package, for example a receptacle, which is in combination with information sufficient to identify a patient having a cavity into which the device may be fitted.
29. A method of fitting a prosthodontics device, the method comprising: (i) selecting a device which has been made to fit in the cavity, in a method according to any of claims ito 26; (ii) using an adhesive and/or cement to secure the device in the cavity.