PROCESS FOR MAKING A DENTAL PROSTHESIS AND MUFFLE CONFIGURED TO ENABLE SAID PROCESS

The present invention relates to a process for making a dental prosthesis, and muffle configured to make said process, of the type specified in the preamble to the first claim.

In particular, the present invention has as its object a process for making a dental prosthesis of a mobile type, total or partial, or fixed or mixed, for example of the mobile prosthesis, overdenture or even all-on-four type, at least partially digitised, and a muffle capable of implementing the process. As is well known, prostheses are made manually by specialised operators with the help of special instruments such as the muffle.

The dental muffle is basically a device comprising at least a mould and a counter mould. The mould is usually a container defining a shape suitable for incorporating a dental prosthesis, while the counter-mould comprises a hollow body, which can be constrainable onto the mould and shaped like the mould itself, and a lid which can be coupled to the hollow body defining holes to allow a fluid to escape during the closing stages of the muffle.

Inside the muffle, therefore, a model containing wax of a prosthesis that is intended to be transformed with a lasting, functional, aesthetic and compatible material with the oral cavity is generally housed.

The conventional processes for the fabrication of prostheses basically comprise, in this order, a phase of casting the mould with plaster in a liquid-viscous state, a phase of inserting the wax model of the prosthesis onto the plaster, a phase of finishing the layer of plaster intended to be coupled with the counter-mould, a coating phase in which the plaster exposed around the model is covered with a thin layer of insulating material a phase in which the tubular element of the counter-mould is coupled with the mould, a further phase in which the plaster in a liquid-viscous state is poured into the counter mould so as to completely cover the wax model, a phase in which the tubular element is closed by means of a lid so as to close the entire mould, a phase in which the mould is heated to soften the wax part so as to prepare it for the subsequent removal phase a removal phase in which, once the muffle has been reopened, the wax part of the model is removed so as to leave only the teeth of the model in the mould, a further phase of covering the exposed plaster with a new layer of insulating material, a phase of placing a resin slurry inside the mould cavity freed from the wax, a phase of re- moulding the mould and counter-mould, several mould and counter-mould pressing phases to remove excess resin residues and to precisely couple the mould and counter-mould, a muffle firing phase to bring the resin to hardness so as to make the actual prosthesis, a phase for removing the prosthesis from the muffle and, possibly, a phase for finishing the prosthesis to remove any defects and/or polish the external surfaces of the prosthesis.

The known technique described includes some important drawbacks.

The internal procedure for making the prosthesis is very long, requires many steps and is completely dependent on the precision with which the physical model is made. Therefore, the prostheses made with conventional procedures are not only operator- dependent, but also economically inconvenient and difficult to reproduce identically. Furthermore, the fabrication of such prostheses include lengthy manual fabrication steps that impact the total cost of the prosthesis as they must be supervised by an operator responsible for controlling them.

To overcome these drawbacks, processes involving CAD modelling systems have been devised. For example, patent application US-A-2010143868 describes a method for manufacturing dental components comprising, in summary, at least one step of making a three-dimensional CAD model of the dental component, a step of sintering or laser melting, based on the layer data for each individual layer of the CAD model, by applying layers of powdered material on a manufacturing platform, a heat treatment step in which the platform and the additionally processed dental component undergo heat treatment and are subsequently cooled, and a surface finishing step of the dental component.

The drawback of this technique is that, in addition to being unsuitable for the fabrication of complete mobile prostheses, it is not compatible with the materials conventionally used for the fabrication of said prostheses. Moreover, in order to be able to make correctly formed parts, it is still necessary to resort to even complex finishing steps.

In this situation, the technical task underlying the present invention is to devise a process for making a dental prosthesis and a muffle configured to carry out said process, capable of substantially obviating at least part of the aforementioned drawbacks.

In the context of said technical task, it is an important aim of the invention to obtain a process for making a dental prosthesis and a muffle configured to make said process, which enable to reduce the manual steps and processes necessary for making a complete prosthesis. Furthermore, a further scope of the invention is to realise a process for making a dental prosthesis and a muffle configured to make said process that are universal and can be effectively used for any dental arch and any material.

In conclusion, a further scope of the invention is to realise a process for making a dental prosthesis and a muffle configured to make said process which enable a prosthesis to be made quickly, cheaply and easily whose result does not depend on the manual skill of the operator.

Moreover, a further aim of the invention is to realise a process, and a muffle thereof, which enable the solution of technical and precision limitations of other systems which manage digital modelling of prostheses, such as, for example, systems which envisage the realisation of the body of the prosthesis and then subsequently bonding the artificial teeth. In fact, these systems in most cases do not envisage the possibility of retouching the teeth and provide a space for gluing the teeth which generates difficulties during gluing and inaccuracies.

In conclusion, a further task of the invention is to realise a process, and relative muffle, which allow to obtain, if required and with the same procedure and equipment, a wax prosthesis for testing starting from the digital modelling so as not to alter the classic protocols adopted in dentistry which provide for aesthetic and functional tests before the realisation of the definitive prosthesis.

The specified technical task and purposes are achieved by a process for making a dental prosthesis, and muffle configured to make said process, as claimed in the appended claim 1.

Preferred technical solutions are disclosed in the dependent claims.

The features and advantages of the invention are hereinafter clarified by the detailed description of preferred embodiments of the invention, with reference to the appended drawings, in which: the Fig. 1 illustrates a perspective view of a muffle configured to carry out a process for making a dental prosthesis according to the invention including both the first moulding support and the second moulding support mutually coupled; the Fig. 2 illustrates a perspective view of a muffle configured to carry out a process for making a dental prosthesis according to the invention in which the first and second moulding supports are mutually decoupled; the Fig. 3 is a perspective view of the first moulding support of a muffle configured to carry out a process for making a dental prosthesis according to the invention in which the first pod is inserted and in which the negative of the dental prosthesis model is visible in transparency; the Fig.4 shows a perspective view of the first moulding support and the pod of Fig. 3 after having obtained the first shaping surface from the first working portion by means of a CNC path; the Fig.5 shows a perspective view of the first moulding support and the pod of Fig. 4 after having arranged the components on the first shaping surface and during the finishing phase; the Fig. 6a illustrates a perspective view of the second moulding support of a muffle configured to carry out a process for making a dental prosthesis according to the invention in which the second pod has been inserted and in which the negative of the dental prosthesis model is visible in transparency; the Fig.6b is a perspective view of the second moulding support and the pod of Fig. 6a after having obtained the second shaping surface from the second working portion; the Fig. 6c is a perspective view of the second moulding support of a muffle configured to carry out a process for making a dental prosthesis according to the invention from which the first moulding support has been removed to surface the finished dental prosthesis; the Fig.7a illustrates a perspective view of the first moulding support of a muffle configured to make a process for making a dental prosthesis according to the invention in which an abundance of material comprising the gingival portion of the prosthesis was poured onto the first shaping surface including the components; the Fig. 7b illustrates a view of the first moulding surface of Fig. 7a following shaping of the gingival portion by removal of material; the Fig. 8 illustrates an exploded view of a muffle configured to carry out a process for making a dental prosthesis according to the invention including lids coupled to both the first and second moulding supports; and the Fig. 9 is an exploded view of a muffle configured to carry out a process for making a dental prosthesis according to the invention in which the lids each include an extractor relief of the relevant pod and the perimeter frames include recesses.

In the present document, the measurements, values, shapes and geometric references (such as perpendicularity and parallelism), when associated with words like “about” or other similar terms such as “approximately” or “substantially”, are to be considered as except for measurement errors or inaccuracies due to production and/or manufacturing errors, and, above all, except for a slight divergence from the value, measurements, shape, or geometric reference with which it is associated. For instance, these terms, if associated with a value, preferably indicate a divergence of not more than 10% of the value.

Moreover, when used, terms such as “first”, “second”, “higher”, “lower”, “main” and “secondary” do not necessarily identify an order, a priority of relationship or a relative position, but can simply be used to clearly distinguish between their different components.

Unless otherwise specified, as results in the following discussions, terms such as “treatment”, “computing”, “determination”, “calculation”, or similar, refer to the action and/or processes of a computer or similar electronic calculation device that manipulates and/or transforms data represented as physical, such as electronic quantities of registers of a computer system and/or memories in, other data similarly represented as physical quantities within computer systems, registers or other storage, transmission or information displaying devices.

The measurements and data reported in this text are to be considered, unless otherwise indicated, as performed in the International Standard Atmosphere ICAO (ISO 2533:1975).

With reference to the Figures, the muffle according to the invention is globally indicated by the number 1.

The muffle 1 is substantially an instrument capable of allowing to create a prosthesis 10 inside within it.

The prosthesis 10 is preferably a dental prosthesis. Thus, it is an artificial element formed on the basis of, for example, a dental impression of a user.

Thus, the prosthesis 10 preferably comprises at least one or more components 10a. Furthermore, the prosthesis 10 may comprise, in addition to the components 10a, a gingival portion 10b.

The components 10a can be artificial dental components, e.g. artificial teeth, attachments or even substructures for fixed prostheses on natural teeth or implants, e.g. crowns and bridges on natural teeth with or without a substructure, partial or full removable prostheses, skeletal, elements on single or multiple implants such as implant arches, all-on-four Toronto or others.

The 10a components can therefore be semi-finished or even elements that can be made on site, e.g. by casting as explained in more detail below.

The gingival portion 10b is the part of the prosthesis 10, if any, suitable to be positioned at the gum wall and/or palate of a user. The muffle 1 defines a tubular body 2. The tubular body 2 is essentially a perforated body within which the hole is through from side to side. For example, the tubular body 2 may define a specific shape, preferably a circular annular shape.

Furthermore, the tubular body 2 is developed around a main axis 2a.

The main axis 2a is substantially the axis of development of the tubular body 2. The tubular body 2 preferably comprises at least one first moulding support 20.

The first moulding support 20 is an element for making at least part of the prosthesis 10. The first moulding support 20 is substantially an element that the branch technician usually recognises as a counter-mould.

In detail, the first moulding support 20 comprises a first perimeter frame 20a and a first slot 20b.

The first perimeter frame 20a substantially defines the support frame of the first moulding support 20. Furthermore, it is preferably, but not necessarily, circular annular. The first perimeter frame 20a also surrounds the first slot 20b.

The first slot 20b is essentially a through hole from side to side. Furthermore, the first slot 20b is preferably extended along the main axis 2a.

The first moulding support 20 additionally defines a first coupling plane 2b. The first coupling plane 2b is substantially transverse to the main axis 2a. Even more preferably, the first coupling plane 2b is perpendicular to the central axis 2a.

The first coupling plane 2b is defined by a surface of the first perimeter frame 20a. Advantageously, the first slot 20b is configured to be filled with a first pod 3. The first pod 3 is also generally known to the branch engineer by the term "rough".

For example, the filling may be done by casting, waiting for the material comprising the first pod 3 to cure within the first slot 20b, or the first pod 3 may be pre-formed and may simply be placed in the first slot 20b. The first pod 3 is substantially preferably composed of a raw material, which can be easily machined by material removal, for example by mechanical milling, suitable for use as a negative of the first moulding support 20.

The first pod 3 also preferably defining a first working portion 30.

The first working portion 30 preferably protrudes from the first moulding support 20 beyond the first coupling plane 2b. Therefore, with respect to the first perimeter frame 20a, the first working portion 30 is exposed and can be machined. Preferably, the first working portion 30 is apt to be machined to obtain thereon, by removal of material, a first hollow shaping surface 30a.

The first shaping surface 30a is substantially a surface defining housings for the components 10a, possibly defining precisely a negative of the same components 10a of the prosthesis 10. Furthermore, the first shaping surface 30a can also define a negative of part of the gingival portion 10b.

The first working portion 30, moreover, is also suitable to be machined to obtain on it, by removal of material, a first coupling surface 30b. The first coupling surface 30b is substantially a surface disposed between the first shaping surface 30a and the first perimeter frame 20a.

Preferably, the first coupling surface 30b is computer processed using a pre-configured algorithm to be perfectly compatible with a second surface as further explained below. Since the first working portion 30 is configured to protrude from the first coupling surface 2b, at least part of the first shaping surface 30a and the first coupling surface 30b advantageously protrude, when machining is complete, from the first coupling surface 2b.

In addition, as already mentioned, if the first pod 3 is pre-formed, i.e. the first working portion 30 is machined before the first pod 3 is inserted into the first slot 20b, the first shaping surface 30a and the first coupling surface 30b, which are always part of the first working surface 30, preferably protrude from the coupling plane 2b once the first pod 3 is inserted into the first slot 20b.

The tubular body 2 of the muffle 1 may comprise, or even substantially consist of, only the first moulding support 20. Or, the tubular body 2 of the muffle 1 may also include a second moulding support 21. The second moulding support 21 is substantially an element that the branch engineer usually recognises as a mould.

In the latter case, the tubular body 2 may substantially comprise first moulding support 20 and second moulding support 21. Even more in detail, the tubular body 2 may be divided into two parts corresponding to first moulding support 20 and second moulding support 21.

The second moulding support 21 is substantially similar to the first moulding support 20. In fact, it has almost the same function and, if present, allows the second moulding support 20 to complete the negative with which to make the entire prosthesis 10. Thus, the second moulding support 21 can be coupled with the first moulding support 20 and can, in this respect, be almost identical to the first moulding support 20. In essence, in this case, the first moulding support 20 and second moulding support 21 are mutually invertible and correspondingly usable.

Or, the first moulding medium 20 and the second moulding medium 21 may be mutually different and not invertible. For example, the first moulding support 20 may define a higher thickness than the second moulding support 21 in order to accommodate most of the prosthesis 10.

Preferably, therefore, the second moulding support 21 is an element that allows at least part of the prosthesis 10 to be made. In detail, the second moulding support 21 comprises a second perimeter frame 21a and a second slot 21b.

The second perimeter frame 21 a substantially defines the support frame of the second moulding support 21. Furthermore, it is preferably, but not necessarily, circular annular. The second perimeter frame 21 a also surrounds the second slot 21 b.

The second slot 21b is essentially a through hole from side to side. Furthermore, the second slot 20b is preferably extended along the main axis 2a.

The first moulding support 20 additionally defines a second coupling plane 2c. The second coupling plane 2c is substantially transverse to the main axis 2a. Even more preferably, the second coupling plane 2c is perpendicular to the main axis 2a.

The second coupling plane 2b is defined by a surface of the second perimeter frame 20a.

Thus, the second coupling plane 2c is capable of being aligned with the first coupling plane 2b when the first moulding support 20 and the second moulding support 21 are coupled. Therefore, the coupling planes 2b, 2c are defined by surfaces of the respective perimeter frames 20a, 21a intended to be mutually contacted when first moulding support 20 and second moulding support 21 are coupled.

Advantageously, the second slot 21b is also configured to be filled with a second pod 4. The second pod 4 is also generally known to the branch coach also with the term "rough".

For example, the filling may be done by casting, waiting for the material comprising the second pod 4 to harden within the second slot 21 b, or the second pod 4 may be pre formed and may simply be placed in the second slot 21 b.

The second pod 4 is substantially preferably composed of a raw material, which can be easily machined by material removal, for example by mechanical milling, suitable for use as a negative of the second moulding support 21. The second pod 4 also preferably defining a second working portion 40.

The second working portion 40 preferably protrudes from the second moulding support 21 beyond the second coupling plane 2c. Therefore, with respect to the second perimeter frame 21 a, the second working portion 40 is exposed and can be machined. Preferably, the second working portion 40 is apt to be machined to obtain thereon, by removal of material, a second shaping surface 40a.

The second shaping surface 40a is substantially a surface defining a negative or part of the one or more components 10a or of the gingival portion 10b of the prosthesis 10. Furthermore, the second shaping surface 40a and the first shaping surface 30a, when first moulding support 20 and second moulding support 21 are coupled, define the complete negative of the entire prosthesis 10.

The second working portion 40, moreover, is also apt to be machined to obtain on it, by removal of material, a second coupling surface 40b. The second coupling surface 40b, similarly to the first coupling surface 40a, is substantially a surface disposed between the second shaping surface 40a and the second perimeter frame 21 a.

Also in this case, since the second working portion 40 is configured to protrude from the second coupling plane 2c, at least part of the second shaping surface 40a and the second coupling surface 40b advantageously protrude, when the machining is finished, from the second coupling plane 2c. Furthermore, if the second pod 4 is preformed, i.e., the second working portion 40 is worked before the second pod 4 is inserted into the second slot 21b, the second shaping surface 40a and the second coupling surface 40b, which are always part of the second machining surface 40, preferably protrude from the second coupling plane 2c once the second pod 4 is inserted into the second slot 21 b. Then, preferably, the second coupling surface 40b is also computer processed using a pre-configured algorithm to be perfectly compatible with the first coupling surface 30b. Even more in detail, the first and second coupling surfaces 30b, 40b are mutually counter-shaped, i.e. they define an identical interface surface and are essentially perfectly capable of being coupled in the sense that the first coupling surface 30b acts as a male element and the second coupling surface 40b acts as a female element or vice versa.

The coupling surfaces 30b, 40b are in detail constructed in such a way that, when coupled, they allow the perimeter frames 20a, 21 a to come into contact at the coupling planes 2b, 2c. To facilitate coupling and facilitate automatic alignment of the parts, the muffle 1 may comprise coupling means 22.

The latter are essentially elements capable of achieving mutual engagement between first moulding means 20 and second moulding means 21.

Preferably, the coupling means 22 comprise a plurality of male elements 22a and corresponding female elements 22b.

The male elements 22a are positioned on one between the first perimeter frame 20a and the second perimeter frame 21 a. For example, they may be pins or dowels or other similar elements.

Thus, in general, they preferably protrude transversally to the first coupling plane 2b or the second coupling plane 2c, for example parallel to the main axis 2a.

Furthermore, they are distributed around the first slot 20b or the second slot 21b, respectively. For example, they may be three in number and distributed around the main axis 2a every 120° as shown in the Figs. 1 -2 and 6a-6c.

The female elements 22b are essentially configured to each accommodate a respective male element 22a. Thus, the female elements 22b may be substantially holes or cavities. Furthermore, the female elements 22b are arranged on the other between the first perimeter frame 20a and the second perimeter frame 21 a around the first slot 20b or around the second slot 21 b respectively.

Therefore, when first moulding support 20 and second moulding support 21 are mutually coupled the male elements 22a are introduced into the female elements 22b so as to block the mutual rotation between first moulding support 20 and second moulding support 21.

The muffle 1 , of course, is intended to be anchored to machinery known in the present state of the art configured to process the pods 3, 4.

Such machinery may include, for example, mechanical cutters or other machinery capable of removing material from the working portions 30, 40.

Thus, the muffle 1 may comprise anchoring means 23.

The anchoring means 23 may be distributed on the first moulding support 20 and/or the second moulding support 21. The anchoring means 23 are configured to allow anchoring of the muffle 1 , in particular respectively the first moulding support 20 and the second moulding support 21 , to the processing machine equipment. Even more in detail, the anchoring means 23 define the important function of allowing the positioning and subsequent repositioning of the first moulding support 20 and/or the second moulding support 21 , at any stage of processing, to maintain the same orientation in the machine, i.e. the same working reference system. This is particularly useful, for example, when it is necessary to remove the muffle 1 from the machine in order to carry out external, for example manual, machining processes, and when it is then necessary to reposition the muffle 1 with the same starting orientation on the machine fixture in order to continue the overall process of making the dental prosthesis 10.

Furthermore, preferably, the anchoring means 23 comprise a plurality of reliefs 23a. The reliefs are substantially protrusions protruding from the first perimeter frame 20a and/or the second perimeter frame 21a radially relative to the main axis 2a. Thus, the reliefs 23a are distributed around the first perimeter frame 20a and/or the second perimeter frame 21 a respectively. Alternatively, the reliefs 23a could be replaced by equivalent means, i.e. by one or more recesses 23b or hollows, as shown in Fig. 9, distributed radially with respect to the main axis 2a and respectively around the first perimeter frame 20a and/or the second perimeter frame 21a.

In general, it is sufficient for the anchoring means 23 to define for the first moulding support 20 and/or for the second moulding support 21, gripping means suitable for allowing attachment to the tooling at fixed positions of the first moulding support 20 and/or for the second moulding support 21.

The muffle 1 allows for a new process for making a dental prosthesis 10.

In particular, the procedure exploits the conformation of the muffle 1 to facilitate the fabrication of the finished article, i.e. the prosthesis 10.

The procedure comprises, in addition to the muffle 1 , a number of fabrication steps. Preferably, the procedure comprises at least one filling phase. In the filling step, at least the first slot 20b is filled with a first pod 3 defining the first working portion 30.

As mentioned above, the first pod 3 may be made by pouring raw material inside of the slot 20b possibly provided with a bottom container case to give a rough shape to the first working portion 30 protruding from the first perimeter frame 20a.

Alternatively, the first pod 3 can be prepared in advance and positioned, i.e. constrained by interlocking, in the first slot 20b on the first perimeter frame 20a.

Of course, in the filling phase, the second slot 21 b of the second moulding support 21 , if present, could also be filled in the same way with the second pod 4 defining the second working portion 40.

Having prepared the first moulding support 20, or the first moulding support 20 together with the second moulding support 21 , an acquisition step may be carried out. Of course, the acquisition step, being independent of the filling step, can also be carried out prior to the filling step.

In the acquisition step, a digital model 5 of the prosthesis 10 is acquired.

This model 5 can be obtained, for example, from a digitally acquired dental impression using an intra-oral scanner. Intra-oral scanners are widely known devices in the current state of the art and the acquisition step is normally carried out by the branch technician. Thus, model 5 may correspond to the computer transposition of the dental impression that is intended to be reproduced as a prosthesis 10 denture. Of course, model 5 may not correspond exactly to the dental impression, since prostheses serve precisely to replace, for example, parts of the dental arch that are no longer intact or present, but it may be the result of elaboration during the acquisition phase or following it.

Or, in the acquisition phase, model 5 may simply be imported into a computer through which at least one subsequent stage of the procedure is realised.

In any event, the methodology by which the model 5 is realised is not particular to the subject matter of the present invention and, as it is widely known, is considered to be obvious to the person skilled in the art.

The process, therefore, comprises a definition phase. In the defining step, at least the first shaping surface 30a hollow is defined. In particular, the first shaping surface 30a is counter-shaped to the model 5 in an area of the prosthesis 10 including one or more components 10a. Furthermore, the shaping step is performed by means of an algorithm implemented in said computer.

Thus, the computer can be configured to interface with any machinery involved in the process in order to control the other process steps based on the acquired and processed model 5.

If the second moulding surface 21 is also provided, the second moulding surface 40a is also defined in the definition phase. Thus, the shaping surfaces 30a, 40a together are counter-moulded to the entire model 5, so that the negative of the entire prosthesis 10 can be replicated.

The procedure thus comprises a machining phase. In the machining step, the first working portion 30 is at least machined by obtaining the first shaping surface 30a on the first working surface 30. If the second moulding medium 21 is also provided, in the machining step the second working portion 40 may also be machined by obtaining the second shaping surface 40a on the second machining surface 40.

In the machining step, substantially computer or computer-controlled CNC routing can be performed on the working portions 30, 40 to derive the shaping surfaces 30a, 40a. The process, advantageously, comprises an introduction phase. In the introduction step, one or more components 10a are introduced onto the first shaping surface 30a. The introduction can take place by simple positioning, for example when the components are semi-finished, or by casting material, for example resin, to enable the components 10a to be made directly on the first shaping surface 30a. This is possible because the first shaping surface 30a, representing the negative of the model 5, includes, for example, recesses for the introduction, by positioning or casting, of artificial teeth and may also include pins for the positioning of, for example, fixed prosthesis frameworks to be embedded in the material intended to make up the gingival portion 10b. If the procedure is intended, for example, for the fabrication of prostheses 10 comprising exclusively components 10a such as a dental bridge, it may essentially also end with the aforementioned introduction step.

Or, the procedure may also include a casting step in which a material, preferably polymeric, is cast to define the gingival portion 10b. The procedure may then be completed in different modes.

For example, in a mode depicted in the Figs. 7a-7b, the procedure may comprise a muffle 1 having only the first moulding support 20 in the absence of the second moulding support 21. Thus, the polymeric material, for example PMMA or wax, may be cast in the casting step such that it protrudes largely beyond the first coupling plane 2b. Then, a further processing step in which the polymeric material is directly removed, as shown in particular in Fig. 7b, may be provided to define the gingival portion 10b of the prosthesis 10.

In a further mode in which the second moulding support 21 is present and as shown in Figs. 6a-6c, the process may comprise, following the casting step, a step of coupling first moulding support 20 and second moulding support 21.

The shape of the gingival portion 10b, according to this second mode, is then defined by the second moulding surface 40a instead of the material removal tools.

Following the coupling, in addition, the procedure may comprise a polymerisation phase. In the polymerisation step, the muffle 1 may be polymerised, for example by baking, by means of a hot polymerizer, for example also an oven.

In addition, the process could further comprise an opening step in which the first moulding support 20 is decoupled from the second moulding support 21 so that the finished prosthesis 10 emerges.

The aforementioned step may, for example, be performed once the prosthesis 10 has hardened. In particular, by decoupling the first moulding support 20, it is possible to make the one or more components 10a of the prosthesis 10 surface.

Of course, the procedure could also include other steps.

For example, the process could include a finishing step, prior to the casting step, in which the components 10a are rectified, for example by mechanical milling.

Finally, the process could include a finishing step in which the entire prosthesis 10 is ground, for example by mechanical milling.

The operation of the muffle 1 described above in structural terms is substantially described in the procedure for making the prosthesis 10. The process of making a dental prosthesis, and the muffle 1 configured to make said process, according to the invention achieve important advantages.

In fact, the process of making a dental prosthesis and the muffle configured to make said process make it possible to eliminate almost all the manual steps of the process and, moreover, to reduce the number of manual steps necessary to make a complete prosthesis.

Moreover, the procedure and the muffle are universal and can be used effectively for any dental arch and any material.

In particular, the pods 3, 4 emerge from the muffle 1 with respect to the coupling plane 2b, 2c, in detail respectively from the first moulding support 20 and the second moulding support 21 , and thus define a blank created within the muffle 1 by inserting the material which hardens and fits into appropriate undercuts adhering precisely and becoming a single body with the muffle 1 itself during processing, i.e. milling. This allows the tool of the milling fixture to easily reach all the necessary inclinations to be able to remove all the excess blank and make moulds and counter-moulds true to CAD modelling without colliding with the fixture or muffle itself. Moreover, even more in detail, the shaping and coupling surfaces 30a, 30b, 40a, 40b delimiting the outline of the surface of the prosthesis by defining favourable zones to allow a correct coupling of first moulding support 20 and second moulding support 21 when the pods 3, 4 are inserted therein and, above all, to allow machining of the tool starting longitudinally from the edge of the prosthesis 10 and continuing to the edge of the muffle 1 in a sinuous course, allowing the cavities and surfaces to be easily reached by the tool.

In fact, if one were to use a planar surface or other surface which does not have the characteristics of the shaping surfaces 30a, 30b, 40a, 40b, i.e. the three-dimensionality and the fact that they are obtained from pods 3, 4 which protrude from the coupling plane 2b, 2c so that they themselves can protrude with respect to it, it would not be possible to make correct moulds and counter-moulds for prosthesis 10 as the tool would not be able to reach all the material to be removed in many situations.

The shaping surfaces 30a, 30b, 40a, 40b and the pod 3, 4 protruding with respect to the coupling plane 2b, 2c determine the favourable conditions for the realisation of the moulds and counter-moulds, given by the sets of first moulding support 20 and first pod 3 and second moulding support 21 and second pod 4, allowing the tool to reach the excess material of the blank to be removed, avoiding the formation of deep and narrow cavities with and without undercuts or inclinations that cannot be reached due to collisions with the blank or the surfaces of the prosthesis 10 itself.

In conclusion, the process and the muffle allow a prosthesis to be made quickly, cheaply and easily from 3D modelling.

The invention is susceptible to variations within the scope of the inventive concept as defined by the claims. For example, one or more of the moulding supports 20, 21 may also comprise a lid 6. The lid 6 may thus be constrainable to the first and/or second perimeter frame 20a, 21 a at a face opposite the working portion 30, 40 of the respective pod 3, 4. The lid 6 could then be constrained to the first perimeter frame 20a and/or the second perimeter frame 21 a parallel to the first coupling plane 2b or the second coupling plane 2c by means of screws or other equivalent means insertable within pre-configured cavities, as shown for example in Fig. 8.

Furthermore, as shown in Fig. 9, the lid 6 may also comprise an extractor relief 60.

If present, the extractor relief 60 is positioned at a face of the lid 6. Furthermore, the extractor relief 60 is substantially protruding transversely, for example normally, to the face of the lid 6.

If the face of the lid 6 comprising the ejector relief 60 faces the first slot 20b or the second slot 21b and the latter comprise a respective pod 3, 4, the ejector relief 60 penetrates at least partially within the first slot 20b or the second slot 21 b and interferes with the respective pod 3, 4 and is substantially configured to push the pod 3, 4 outwardly of the respective slot 20b, 21 b. Thus, the extractor relief 60 is configured to interfere with the pod 3, 4 to remove it from the respective moulding support 20, 21. Therefore, if the lid 6 comprises an extractor relief 60, it may be used according to two modes: one in which the extractor relief 60 faces outwards from the tubular body 2 and the lid 6 has the sole function of plugging the first moulding support 20 or the second moulding support, and a second mode in which the extractor relief 60 is introduced into a slot 20b, 21 b and interferes with the pod 3, 4 to allow its extraction.

In this respect, all details are replaceable by equivalent elements and the materials, shapes and dimensions can be any.