WO2007015140A2

WO2007015140A2 - Work station and method to build up a surgical template to guide the insertion of osteointegrated implants in the maxillary arches

Info

Publication number: WO2007015140A2
Application number: PCT/IB2006/002091
Authority: WO
Inventors: Leonardo Ciocca; Roberto Scotti; Roberto Mingucci; Giovanni Bacci
Original assignee: Alma Mater Studiorum - Universita' Di Bologna
Priority date: 2005-08-02
Filing date: 2006-08-01
Publication date: 2007-02-08
Also published as: ITTO20050542A1; WO2007015140A8; EP1922015A2; WO2007015140A3

Abstract

Method and work station (1) to build up a surgical template (2) guide, in which at least one real stone cast (4) of the dental arches is made, attached to the real stone cast (4) is a tracking system (17) made taking a three dimensional scan of the surfaces of the real stone (4) cast in order to obtain a virtual reproduction (18) of the teeth and/or the dental mucosa including the tracking system (17), this same tracking system (17) as attached to the real stone cast (4) is applied onto the patient and a CT (computed tomography) scan is performed in order to obtain a three dimensional virtual reproduction (19) of at least the part of the skull showing the tracking system (17), this virtual three dimensional reproduction (19) is then integrated with the virtual reproduction (18) of the teeth and/or the dental mucosa in order to plan the dental implant in a virtual environment, and to create the surgical template guide (2) using the results of the virtual planning.

Description

WORK STATION AND METHOD TO BUILD UP A SURGICAL TEMPLATE TO GUIDE THE INSERTION OF OSTEOINTEGRATED IMPLANTS IN THE MAXILLARY ARCHES

TECHNICAL FIELD

This invention relates to a method and a work station to build a surgical template to guide the insertion of osteointegrated implants into the maxillary arches . BACKGROUND ART

To rehabilitate by means of an osteointegrated implant gaps in the teeth resulting from loss of teeth due to periodontal illness or other causes, modern techniques of oral osteointegrated implantology require the preparation of the implant site by means of controlled speed rotating shaping tools mounted on a hand piece. The osteointegrated implant is then inserted into position by the same controlled torque instruments.

The most complicated stage of the implant procedure described above is the perforation of the bony arch in order to position the implant into that same arch, as even tiny errors of positioning of the angle and of the depth of the implant site may compromise the final result of the implant not only from the aesthetic point of view, but also from the functional one (occlusion, masticatory function, and phonetic function) Furthermore, during the perforation of the bony arch it is essential not to compromise the nervous and vascular system present in the bony arch itself.

In order to assist the dentist in creating the implant site, the use of a surgical template guide has been introduced, which is inserted into the dental arch before perforating the bony arch. The surgical template guide is marked with the guide holes which have been positioned so as to be exactly co-axial to the hole that must be made in the bone of the dental arch; consequently, once the surgical template guide is in position in the dental arch, the dentist only has to insert the tip of the calibrated bur into each hole in the template in order to precisely position the implant into the bony arch. Preferably, the guide hole of the template for the perforation of the surgical template guide is lined with a calibrated metal sleeve, which was manufactured by the same manufacturer that made the dental implant and which has an internal diameter corresponding to the external diameter of the calibrated surgical bur being used.

The precision of the hole made through the bone of the dental arch, the template guide itself, and in particular the perforation guide the template will be much made much more precisely. Until a few years ago, surgical template guides for the insertion of osteointegrated implants in the maxillary arches were made entirely manually with the aid of stone casts of the dental arches of the patient. In order to increase the precision of the surgical templates used to guide the insertion of osteointegrated implants in the maxillary arches it has recently been proposed to create these template guides by using a CAD/CAM technique which is based upon a three dimensional reproduction of the skull as obtained by a CT (computed tomography) scan of the maxillary arches .

An example of the use of a CAD/CAM technique for the creation of a surgical template guide for the insertion of osteointegrated implants into the maxillary arches is described in the article "An immediately loaded CAD/CAM- guided definitive prosthesis: A clinical report" - Christopher B. Marchack - The Journal of Prosthetic Dentistry - 2005- Volume 93 - Number 1. Another example of the use of a CAD/CAM technique to make a surgical template guide for the insertion of osteointegrated implants in the maxilla is described in Patent Application US2004078212. The above described CAD/CAM technique for making a surgical template guide for the insertion of osteointegrated implants into the maxillary arches requires the making of suitable dental prosthesis which will be inserted into the mouth of the patient and the fixing of radio-opaque markers (gutta percha) in order to define a tracking system within the dental prosthesis. Next the dental prosthesis is inserted into the mouth of the patient and the first CT (computed tomography) scan of the maxillary arches of the patient is made in order to obtain a three dimensional virtual reproduction of the maxillary zone with specific reference to the bony structure supporting the dental arches. At this point, the dental prosthesis is removed from the mouth of the patient and a second CT (computed tomography) scan of the prosthesis is made to obtain a three dimensional virtual reproduction of the negative of the maxillary zone with particular reference to the positioning of the teeth.

The two three dimensional virtual reproductions of the maxillary zone obtained by the two CT (computer tomography) scans are superimposed and integrated so as to obtain a single integrated three dimensional virtual reproduction of the maxillary area. At this point, using the integrated three dimensional virtual reproduction of the maxillary zone and using a software designed to three dimensionally plan dental implants, the dental implant and therefore the perforation guide for positioning the dental implant can be virtually planned. Finally, the surgical template guide can be created using the integrated three dimensional virtual reproduction of the maxillary zone and the result of the virtual planning of the dental implant, in particular, a virtual reproduction of the surgical template is made and therefore the surgical template guide is produced from the virtual reproduction of the surgical template guide itself using a three dimensional stereo lithographic printer.

The CAD/CAM methodology described above is generally more precise than traditional manual methods. Nevertheless, the CAD/CAM methodology described above does not always result in a precision that is significantly greater so as to guarantee an optimal result in the dental implant, in particular, the results are insufficiently precise when metal bridges are present as they screen the area surrounding them during the execution of the CT (computed tomography) scan. Furthermore, the CAD/CAM methodology described above calls for an initial CT (computed tomography) scan of the patient and a second CT (computed tomography) scan of the prosthesis, these CT (computed tomography) scans cannot always be easily performed in the public hospital environments in which the majority of patients undergo X- ray analysis.

DISCLOSURE OF INVENTION The aim of the present invention is to provide a method and a work station to produce a surgical template guide for the insertion of an osteointegrated implant into the maxillary arches, in which this method and this work station are free of the inconveniences as described above, and at the same time, are simple and inexpensive to use. In accordance with this invention are provided a method and a work station to make a surgical template guide for the insertion of an osteointegrated implant in the maxillary arches as claimed in the attached claims. BRIEF DESCRIPTION OF THE DRAWINGS

This invention will now be described with reference to the attached illustrations, which show a non- restrictive actual example, in which: figure 1 shows schematically the principal components of a work station to make surgical template guides in accordance with the present invention; figure 2 is a photograph of various markers as used in the work station shown in figure 1; - figure 3 is a photograph of a stone cast of the lower dental arch of a patient who must undergo surgery for an oral implant; figure 4 is a photograph of a stone cast of the upper dental arch of the patient; - figure 5 is a photograph of a surgical template for occlusion of the lower dental arch of the patient; figure 6 is a photograph of a surgical template for occlusion of the upper dental arch of the patient; figure 7 is a photograph of the stone casts of the dental arches of figures 3 and 4, mounted in an articulator and with the insertion of the two surgical templates for occlusion of figures 5 and 6; figures 8 and 9 are two photographs of different surgical templates for occlusion of the lower dental arch for another patient; figures 10 and 11 are two photographs of the surgical template for occlusion as seen in figures 8 and 9 with special markers attached for recasting figures 12 and 13 are two different three dimensional images of the patient's skull as obtained using a CT (computed tomography) scan; figure 14 is a three dimensional image of the patient' s skull obtained by integrating the result of a CT (computed tomography) scan with the result of scanning the surfaces of the stone casts of the dental arches of figures 3 and 4; figures 15, 16, and 17 show three images of part of the three dimensional image of figure 14 of the patient's skull sectioned lengthwise on a vertical plane for the planning of the template guide for the insertion of the osteointegrated implant into the maxillary arches; figure 18 shows a detail of a sectioned three dimensional image of the patient's skull during the virtual positioning of an implant and showing the surgical template guide; figure 19 shows schematically the making of a hole by means of a real template guide for the insertion of osteointegrated implants into the maxillary arches created by means of a virtual model using a stereo lithographic printer; figure 20 shows a detail of the three dimensional image of the patient's skull of figure 14, sectioned lengthwise on the vertical plane and with the addition of part of the virtual surgical template guide; figures 21 and 22 show two three dimensional reproductions of the virtual surgical template guide of figure 20; and figures 23 and 24 show two three dimensional reproductions of the virtual template guide of figure 20 overlaid onto an image obtained by means of scanning the surfaces of the stone cast of the upper dental arches of figure 4. BEST MODE FOR CARRYING OUT THE INVENTION In figure 1 number 1 indicates a work station to create a template 2 guide in resin (illustrated in figure 19) for the insertion of an osteointegrated implant in the maxillary arches. Depending on the size of the implant needed, it is possible to make either a single template 2 guide or many template 2 guides . Work 1 station includes dental 3 casts to make real stone 4 casts (illustrated in figures 3 and 4) or casts in other materials using a standard and well known method that are equivalent to the dental arches of the patient, in particular, a real stone 4 cast of the lower arch

(figure 4) and a real stone 4 cast of the upper arch

(figure 3) are made. Once made, the real stone 4 casts are mounted in an articulator 5 (illustrated in figure 7) which reproduces the movement of the mandible of the patient and reproduces the correct intermaxillary relation between the two real stone 4 casts.

The work 1 station uses impressions 6 in order to make two dental 7 prostheses (illustrated in figures 5 and 6) , one for the upper dental arch and the other for the lower dental arch. As shown in figures 5 and 6, the two dental 7 prostheses may be shaped like the bases of the occlusion in such a way that when inserted into the patient's mouth they keep the patient's mandible in a predetermined fixed position (typically the condyle is positioned in the glenoid fossa ) . Alternatively, as seen in figures 8 and 9, the dental 7 prostheses may be shaped like the bases of the occlusion and in this case already show the shape of the teeth. The two dental 7 prostheses are made using the impressions 6 and using the real stone 4 casts of the patient's dental arches mounted in the articulator 5. The work 1 station includes a series of markers 8 detectable both by scanning the surfaces and by CT

(computed tomography) scan; furthermore, the markers 8 are connectable to the real stone 4 casts and/or to the dental 7 prostheses.

According to the first shape of the markers 8 which are illustrated with an unbroken line in figure 1, each marker 8 is spherical in shape and is made from titanium and has a diameter of from 1 to 4 mm; in this case each marker 8 is glued directly onto the external surface of the stone 4 casts or the dental 7 prostheses using a cyanoacrylic 9 glue.

According to the alternative shape as illustrated with a broken line in figure 1, each marker 8 is a sphere from which protrudes a connecting 10 rod; in this case, each marker 8 is connected to the stone 4 cast of the dental arch, or to the dental 7 prosthesis by inserting the connecting 10 rod of the marker 8 into the body of the real stone 4 cast or into the body of the dental 7 prosthesis. Normally, the connecting 10 rod of a marker 8 may be inserted into the body of a real stone 4 cast or of a dental 7 prosthesis while casting the real stone 4 cast or while casting the resin for the dental 7 prosthesis. Alternatively, the connecting 10 rod of the marker 8 may be inserted in the body of a stone 4 cast or a dental 7 prosthesis after creating the real stone 4 cast or the dental 7 prosthesis; in this latter case, the real stone 4 cast or the dental 7 prosthesis must be perforated using a drill to make holes suitable to receive the connecting 10 rod. Figure 2 shows both the spherical titanium markers 8 and the markers 8 to which are fixed the connecting 10 rods and which are made from a coloured plastic material.

Finally, the work 1 station includes a computer 11 which is directly or indirectly linked to a three dimensional 12 scanner (either laser or optic) , a device 13 to make three dimensional CT (computed tomography) scans of the patient's skull, and a three dimensional stereo lithographic 14 printer.

On the computer 11 is installed graphic design software 15 to allow the integration of the two three dimensional digital images; to name one such software 15 as an example is The Visualization Toolkit (www. vtk. org) . On the computer 11 is also installed three dimensional software 16 that allows for the planning of dental implants, such as the three dimensional software for planning dental implants developed by Medicim in Sint- Niklaas (Belgium) .

Here follows a description of the steps to be followed to make a surgical template 2 guide using the above described work 1 station. As has been previously described, the work 1 station uses known methods to make the real stone 4 casts of the dental arches of the patient; once made, the real stone 4 casts are mounted in the articulator 5 which reproduces the intermaxillary relationships and the movement of the mandible of the patient. Next, using the real stone 4 casts of the patient's dental arches mounted into the articulator 5 the dental 7 prostheses are made, and are shaped in such a way as to conform to the mouth of the patient. If the dental 7 prostheses are made as the bases for the occlusion, then in the occlusion and in the corrected position of the arch are mounted in the real stone 4 casts of the bases of the occlusion with the teeth on the wax, and each mounting can be duplicated using conventional orthodontic techniques in the dental 7 prosthesis which shows therefore the shapes of the teeth and the occlusion as predetermined in the articulator. At this point, onto the real stone 4 casts of the dental arches a number of markers 8 are attached in such a way as to link the real stone 4 casts with the tracking system 17 (illustrated in figures 3 and 4) . Following the preferred method of accomplishing this, the tracking 17 system includes the markers 8 arranged in such a way as to correspond to each implant site, that is, corresponding to where an implant will be positioned; in particular, each marker 8 is arranged in a locatable position corresponding exactly to the central axis of the tooth. Typically, the markers 8 are positioned directly in contact with the dental/gingival surface of the real stone 4 casts of the dental arches. In each case, there must be arranged at least three markers 8 attached to the real stone 4 cast of the upper arches and at least three markers 8 attached to the real stone 4 cast of the lower arches; the presence of at least three unaligned markers 8 is necessary in order to define in an unambiguous way the three dimensional tracking 17 system.

In other words, a marker is placed in correspondence to the implant site of each implant (that is, in correspondence to where the implant will be positioned) . If several implants need to be positioned within the same dental arch, then such markers 8 arranged in correspondence to the implant site of each implant are sufficiently numerous to define the tracking 17 system within the dental arch in question; if only one or two implants are arranged within the same dental arch, then such markers 8 arranged in correspondence to the implant site for each implant are not sufficient in number to define the tracking 17 system of the dental arch in question, and therefore it is necessary to arrange more markers 8 until you reach a minimum number of three.

Once the tracking 17 system is in place on the real stone 4 casts of the dental arches, the real stone 4 casts surfaces are scanned by a three dimensional scanner 12 in order to obtain a virtual 18 reproduction of the teeth and/or the dental mucosa (illustrated in figure 14) including the tracking 17 system. It is important to ensure that the virtual 18 reproduction includes not only the teeth, but also some of the dental mucosa in the case of the dentulous patient, whereas for an edentulous patient only the dental mucosa is shown in the virtual 18 reproduction.

One way of doing this is that each marker 8 is externally painted a colour that is opaque and that is also different from the colour of the real stone 4 casts.

At this point, to the patient is applied the same tracking 17 system previously copied onto the real stone 4 casts of the dental arches; the one that resulted from applying the dental 7 prostheses onto the real stone 4 casts of the dental arches in order to transfer the tracking 17 system from the real stone 4 casts of the dental arches to the dental 7 prostheses and therefore the dental 7 prostheses complete with tracking 17 system are inserted into the mouth of the patient.

Using the first shape of the markers 8 , in order to transfer the tracking 17 system of the real stone 4 casts of the dental arches onto the dental 7 prostheses cavities need to be dug into the dental 7 prostheses which correspond to the position of the markers 8 and then each cavity is filled with a resin in a plastic state, and finally the dental 7 prostheses are applied onto the real stone 4 casts of the dental arches in order to obtain a negative imprint of the markers 8. Once the negative imprint of the markers 8 is obtained, the dental 7 prostheses are left attached to the real stone 4 casts of the dental arches until the resin has solidified so as to incorporate the markers 8 so that when the dental 7 prostheses are separated from the real stone 4 casts of the dental arches the markers 8 themselves go with them. Alternatively, once the negative imprint of the markers 8 is obtained the dental 7 prostheses are separated from the real stone 4 casts of the dental arches while the resin is still in a plastic state and into the negative imprints are inserted new markers 8 having the same shape and the same dimensions as the markers 8 attached to the real stone 4 casts of the dental arches; however, this method is slightly less precise than the methodology described above. Once the dental 7 prostheses complete with the tracking 17 system have been inserted into the mouth of the patient, a CT (computed tomography) scan is made of the maxillary arches of the patient in order to obtain a virtual 19 three dimensional reproduction (illustrated in figures 12 and 13) of the skull including the tracking 17 system.

Depending on what is shown above, the three dimensional scan of the surfaces of the real stone 4 casts can be done before the CT (computed tomography) scan of the maxillary arches of the patient, or alternatively the CT (computed tomography) scan of the maxillary arches of the patient can be done before the three dimensional scan of the surfaces of the real stone 4 casts.

The above described methodology enables us to have at our disposal the real stone 4 casts with the tracking 17 system attached in order to make the three dimensional scan of the surfaces in such a way as to obtain the virtual 18 reproduction of the teeth and/or the dental mucosa. In some situations, you might have available only the virtual 19 three dimensional reproduction of the skull showing the tracking 17 system as obtained by the CT (computed tomography) scan of the maxillary arches of the patient and the dental 7 prostheses fitted with the tracking 17 system; in other words, the original real stone 4 casts are not available. In this case, it is necessary to make a copy of the original real stone 4 casts by recasting them using the dental 7 prostheses.

To transfer the tracking 17 system from a dental 7 prosthesis to the corresponding copy of the real stone 4 cast, the markers 8 are not connected directly to the dental 7 prosthesis, but are inserted into semi-spherical housing 20 seats (shown in figures 9 and 10) and sunk well into their interior so that they become embedded into the dental 7 prosthesis; preferably the housing 20 seats are made of Teflon or a similar material having a certain elasticity such that they retain the markers 8 securely and yet permit the insertion/extraction of the markers 8 into/out of the same housing 20 seats. Before recasting a copy of the real stone 4 cast using the dental 7 prosthesis, the titanium spherical markers 8 of the dental 7 prosthesis are substituted with plastic markers 8 (for scanning the surfaces it is not necessary to use titanium, which is much more expensive than plastic) having connecting 10 rods which protrude from the dental 7 prosthesis (as illustrated in figures 10 and 11) , in this way, the connecting 10 rods of the markers 8 are submerged into the body of the copy of the real stone 4 cast and when the copy of the real stone 4 cast is separated from the dental 7 prosthesis the markers 8 remain in the copy of the real stone 4 cast and separate from the dental 7 prosthesis.

At this point, the graphic design software 15 is used to elaborate the virtual 19 three dimensional reproduction of the skull with the virtual 18 reproduction of the teeth and/or the dental mucosa so as to superimpose the images of the tracking 17 system present in the virtual 19 three dimensional reproduction of the skull with the tracking 17 system present in the virtual 18 reproduction of the teeth and/or the dental mucosa. In other words, the result of the CT (computer tomography) scan is combined with the result of the scan of the surfaces, in such a way as to have exact conformation of the bone structure (computed tomography) with exact conformation of the surfaces of the dental arch (scan of surfaces) . Figure 14 shows a virtual 19 three dimensional reproduction of the skull integrated with the virtual 18 reproduction of the teeth and/or the dental mucosa.

It is important to underscore that the CT (computed tomography) of the maxillary arches of the patient does not allow for a good reproduction of the teeth and especially of the dental mucosa due to the need to limit the radiation load to which the patient' s head is exposed

(in particular, the scan must be made with a step of no less than about lmm) . By contrast, the scan of the surfaces of the real stone 4 casts of the dental arches allows a very accurate and precise reproduction of the teeth and the above all, of the dental mucosa. The integration of the virtual 19 three dimensional reproduction of the skull with the virtual 18 reproduction of the teeth and/or the oral mucosa gives a final result that is extremely faithful and reduces to a minimum the unavoidable load of radiation to which the patient is exposed. Simply, another way of doing this is that in order to obtain a virtual 18 reproduction of the teeth and/or the dental mucosa including the tracking 17 system instead of scanning the surfaces of the real stone 4 casts of the dental arches it is possible to scan the surfaces of the dental 7 prostheses instead. In this case it is necessary that the markers 8 are in the vestibular surface (cheek) of the dental 7 prostheses because if they are enclosed within the dental 7 prostheses they will not be visible on the scan of the surfaces . It is important to underscore that the scan of the surfaces of the dental 7 prostheses results in a virtual 18 reproduction of the teeth and/or the dental mucosa with a precision that is inferior to scanning the surfaces of the real stone 4 casts; in consequence, whenever possible, it is always preferable to obtain the virtual 18 reproduction of the teeth and/or the dental mucosa by scanning the surfaces of the real stone 4 casts.

Using the virtual 19 three dimensional reproduction of the skull integrated with the virtual 18 reproduction of the teeth and/or the dental mucosa allows for the virtual planning of the dental implant, and therefore for the relevant holes for the support of the dental implant itself. In particular, as illustrated in figures 15, 16, and 17, in correspondence to each marker 8 that identifies a site in which to implant an implant, the integrated image of the virtual 19 three dimensional reproduction of the skull and the virtual 18 reproduction of the teeth and/or the dental mucosa is sectioned lengthwise on a vertical plane, in this way it becomes easy to identify the axis 21 of insertion of the implant (figure 18) and subsequently to choose the length and the size of the implant from amongst the commercially available alternatives (figure 18). At this point (still referring to figure 18) the metal 22 roots of the implant can be virtually positioned inside the integrated image of the virtual 19 three dimensional reproduction of the skull and the virtual 18 reproduction of the teeth and/or the dental mucosa. Subsequently, depending on the result shown in figure 18 within the integrated image of the virtual 19 three dimensional reproduction of the skull and the virtual 18 reproduction of the teeth and/or the dental mucosa a virtual surgical template 2 guide is created, which reproduces in negative the shape of the dental arches and/or the dental mucosa; and finally, the virtual surgical template 2 guide is perforated by a virtual guide 23 hole, which is co-axial to the axis 21 of insertion of the implant and has a diameter that receives without play the calibrated metal guide 24 sleeve (illustrated in figure 19) appropriate to the chosen implant .

The real surgical template 2 guide is made by using the virtual surgical template 2 guide and the three dimensional stereo lithographic 14 printer, and subsequently, into the guide 23 holes of the real surgical template 2 guide are inserted the calibrated metal guide 24 sleeves (illustrated in figure 19) belonging to the chosen implant. Alternatively, the virtual surgical template 2 guide may be used to drive a numerically controlled machine tool in such a way as to obtain the real surgical template 2 guide from a block of resin.

As seen in the diagram in figure 19, in practice, the real surgical template 2 guide is then positioned onto the dental arches of the patient and the holes through the dental arch are made by inserting the tip of the bur into the guide 23 holes.

Figure 20 shows part of the three dimensional image of the skull of the patient of figure 14 sectioned lengthwise on the vertical plane and with the addition of part of the virtual template 2 guide containing the virtual 24 sleeves. Figures 21 and 22 show two three dimensional reproductions of the virtual template 2 guide of figure 20; in figure 21 the guide holes 23 and the relative axes 21 are indicated, while in figure 22 the virtual guide 24 sleeves are indicated. Finally, in figures 23 and 24 are shown two three dimensional reproductions of the virtual template 2 guide of figure 20 overlaying a virtual 18 reproduction of the teeth and/or dental mucosa as obtained by scanning the surfaces of the stone 4 cast of the upper dental arch shown in figure 4. Figure 23 shows the guide 23 holes and the images of the markers 8, while figure 24 shows the virtual sleeves 24. A template 2 guide such as the one described above can be used in combination with various surgical intervention methods; for example, it can be used in the "flap surgery" technique for positioning implants; in "one-stage" surgical technique; in the "transmucosal implants" surgical technique; and in the "minimal intervention" surgical technique. In this last case, the calibrated metal guide 24 sleeves are made from titanium and must protrude from the edge of the surgical template 2 guide towards the mucosa and have the contour of a circular scalpel, such as determines the first incision of a gingival operculum. From what is shown above, clear results of the CT (computed tomography) of the maxillary of the patient do not always result in a good reproduction of the teeth, and above all of the dental mucosa because the mucosa is relatively transparent to radiation, and because it is necessary to limit the radiation load to which the patient's head is exposed (it is important that the scan is done with a step of about lmm) . For these reasons it is necessary to integrate the virtual 19 three dimensional reproduction of the skull obtained by CT (computed tomography) with the virtual 18 reproduction of the teeth and/or the dental mucosa obtained by scanning the surfaces of the stone 4 casts of the dental arches or as obtained by scanning the surfaces of the dental 7 prostheses . The method described above to make a surgical template 2 guide for the insertion of an osteointegrated implant into the maxillary arches presents various advantages, as it is quick and inexpensive to make and allows high precision transfer between the simulation made in the virtual environment and the workplace. Furthermore, each method can be used equally well on patients who are completely or partially dentulous, that is to say, patients who have all or some of their teeth, and on edentulous patients, that is those patients who are without teeth, or who have few remaining teeth.

Claims

1) Method to make a template (2) guide for the insertion of an osteointegrated implant in the maxillary arches; the method consisting of the following steps: to use a integrated image of the virtual (19) three dimensional reproduction of the skull and a virtual (18) reproduction of the teeth and/or the dental mucosa in order to plan virtually the implant and to determine the size and the position of the holes for the support of said implant; to make at least one virtual template (2) guide within the integrated image of the virtual (19) three dimensional reproduction of the skull and the virtual (18) reproduction of the teeth and/or the dental mucosa; to produce at least one virtual guide (23) hole in the virtual template (2) guide corresponding to the site in which to implant the implant; to make at least one real template (2) guide showing the guide (23) hole using the virtual template (2) guide; the method is characterised by the fact of including the further steps of: to create at least a real stone (4) cast of the dental arches of the patient; to connect to the real stone (4) cast of the dental arches the tracking (17) system composed of a number of markers (8) ; to scan the three dimensional surfaces of the real stone (4) cast of the dental arches including the tracking (17) system in order to obtain a virtual (18) reproduction of the teeth and/or the dental mucosa including the tracking (17) system; to apply to the patient the same tracking (17) system as used in the real stone (4) cast of the dental arches; to make a CT (computed tomography) scan of the maxillary arches of the patient in order to obtain a virtual (19) three dimensional reproduction of at least part of the skull showing the tracking (17) system; and to integrate the virtual (19) three dimensional reproduction of the skull with the virtual (18) reproduction of the teeth and/or of the dental mucosa so as to superimpose the images of the tracking (17) system present in the virtual (19) three dimensional reproduction of the skull with the images of the tracking (17) system present in the virtual (18) reproduction of the teeth and/or the dental mucosa.

2) Method according to claim 1, wherein the same tracking (17) system attached to the real stone (4) cast of the dental arches is applied to the patient in the following steps: to make at least one dental (7) prosthesis using the real stone (4) cast of the dental arches of the patient; to attach to the dental (7) prosthesis the same tracking (17) system as attached to the real stone (4) cast of the dental arches; and to insert into the mouth of the patient the dental (7) prosthesis with the tracking (17) system attached before making the CT scan of the maxillary arches of the patient in order to obtain the three dimensional virtual

(19) reproduction of the skull including the tracking

(17) system. 3) Method according to claim 2, wherein to obtain a virtual (18) reproduction of the teeth and/or dental mucosa including the tracking (17) system a three dimensional scan of the surfaces of the dental (7) prosthesis including the tracking (17) system is made instead of a three dimensional scan of the surfaces of the real stone (4) cast of the dental arches including the tracking (17) system.

4) Method according to claim 2 or 3, wherein to apply to the dental (7) prosthesis the same tracking (17) system as attached to the real stone (4) cast of the dental arches the dental (7) prosthesis is overlaid onto the real stone (4) cast of the dental arches.

5) Method according to claim 4, wherein the tracking (17) system is made contemporaneously in the real stone (4) cast and in the dental (7) prosthesis. 6) Method according to claim 4, wherein the attachment of the tracking system (17) onto the dental (7) prosthesis is comprised of the following steps: to dig cavities in the dental (7) prosthesis to correspond with the positions of the markers (8); to fill the cavities made in the dental (7) prosthesis with a resin in its plastic state; and to overlay the dental (7) prostheses onto the real stone (4) casts of the dental arches to obtain a negative imprint of the markers (8) .

7) Method according to claim 6, wherein once the negative imprint of the markers (8) is obtained the dental (7) prostheses are separated from the real stone (4) cast of the dental arches while the resin is still in a plastic state and into the negative imprints are inserted new markers (8) of the same shape and the same size as the markers (8) associated with the real stone (4) casts of the dental arches.

8) Method according to claim 6, wherein once the negative imprint of the markers (8) is obtained the dental (7) prostheses are left overlaid on the real stone (4) casts of the dental arches until the resin has solidified in order to embed the markers (8) and is then separated from the real stone (4) casts of the dental arches taking the markers (8) with them.

9) Method according to claim 1, wherein the same tracking (17) system attached to the real stone (4) cast of the dental arches is applied to the patient in the following steps: to make at least one dental (7) prosthesis; to apply to the dental (7) prosthesis a tracking (17) system; and to insert into the mouth of the patient the dental

(7) prosthesis with the attached tracking (17) system before making the CT scan of the maxillary arches of the patient in order to obtain the three dimensional virtual (19) reproduction of the skull including the tracking

(17) system.

10) Method according to claim 9, wherein to obtain a virtual (18) reproduction of the teeth and/or dental mucosa including the tracking (17) system a scan of the three dimensional surfaces of the dental (7) prosthesis with attached tracking (17) system is made instead of scanning the three dimensional surfaces of the real stone

(4) cast of the dental arches with attached tracking (17) system. 11) Method according to claim 9, wherein the real stone (4) cast of the dental arches with attached tracking (17) system is made using the dental (7) prosthesis with attached tracking (17) system by means of casting. 12) Method according to claim 11, wherein before casting the real stone (4) cast of the dental arches, the markers (8) defining the tracking (17) system of the dental (7) prosthesis are substituted with similar markers (8) with attached connecting (10) rods; in this way, the connecting (10) rods of the markers (8) are submerged into the body of the real stone (4) cast and at the moment of separating the real stone (4) cast from the dental (7) prosthesis the markers (8) remain in the real stone (4) cast and separate from the dental (7) prosthesis .

13) Method according to claim 12, wherein the markers (8) are inserted into semi spherical housing (20) seats and are sunk well into the interior of the dental (7) prosthesis.

14) Method according to claim 13, wherein the housing (20) seats have a certain elasticity such that they retain the markers (8) securely and yet permit insertion/extraction of the markers (8) into/out of the same housing (20) seats.

15) Method according to claim 14, wherein the housing (20) seats are made of Teflon. 16) Method according to one of the claims from 1 to 15, wherein each marker (8) of the tracking (17) system is placed in direct contact with the dental/gingival surfaces of the real stone (4) model.

17) Method according to one of the claims from 1 to 16, wherein each marker (8) of the tracking (17) system is spherically shaped, and is made of titanium and has a diameter between 1 and 4mm. 18) Method according to claim 17, wherein each marker (8) is a perfect sphere and is attached to the respective real stone (4) cast of a dental arch by the medium of a glue (9) . 19) Method according to claim 17, wherein each marker (8) has a spherical head from which protrudes a connecting (10) rod; each marker (8) is connected to the respective real stone (4) cast of a dental arch by inserting the connecting (10) rod of the marker (8) into the core of the same real stone (4) cast.

20) Method according to one of the claims froml to 19, wherein each marker (8) is made of titanium and is externally painted with an opaque colour.

21) Method according to one of the claims froml to 20, wherein the markers (8) are inserted into semi spherical housing (20) seats and are sunk well into the interior of the dental (7) prosthesis such that they become embedded.

22) Method according to claim 21, wherein the housing (20) seats have a certain elasticity such that they retain the markers (8) securely and yet permit insertion/extraction of the markers (8) into/out of the same housing (20) seats.

23) Method according to claim 22, wherein the housing (20) seats are made of Teflon. 24) Method according to one of the claims from 1 to 23, wherein the tracking (17) system comprises a marker (8) placed to correspond with each implant site.

25) Method according to claim 24, wherein a marker (8) associated with an implant site is arranged in a tracking point corresponding exactly to the central axis of the tooth.

26) Method according to claim 24 or 25, wherein, in correspondence to each marker (8) that designates the implant site of an implant, the integrated image of the virtual (19) three dimensional reproduction (19) of the skull and the virtual (18) reproduction of the teeth and/or the dental mucosa is sectioned lengthwise on a vertical plane to determine the axis (21) of insertion of the implant and subsequently to determine the length and the size of the implant.

27) Method according to one of the claims from 1 to

26, wherein each virtual surgical template (2) guide is made using the same virtual surgical template 2 guide by copying the negative of the shape of the dental arches and/or the dental mucosa.

28) Method according to one of the claims from 1 to

27, wherein the virtual surgical template (2) guide is perforated with a virtual guide (23) hole, the which is coaxial to the axis (21) of insertion of the implant and is of a diameter into which snugly fits without play the calibrated metal guide (24) sleeve belonging to the chosen implant.

29) Method according to claim 28, wherein into the guide (23) hole of the real surgical template (2) guide is inserted a calibrated metal guide (24) sleeve belonging to the chosen implant.

30) Method according to one of the claims from 1 to 29, wherein the real surgical template (2) guide is made from the virtual surgical template (2) guide using a three dimensional stereo lithographic printer (14) .

31) Method according to one of the claims from 1 to 29, wherein the virtual surgical template (2) guide is used to drive a numerically controlled machine tool so as to obtain the real surgical template (2) guide from a block of resin.

32) Work (1) station to make a surgical template (2) guide for the insertion of an osteointegrated implant into the maxillary arches; the work station comprises: the dental (3) impressions to make at least one real stone (4) cast of the dental arches of the patient; a series of markers (8) that are detectable by scanning the surfaces or by CT (computed tomography) ; the means (9) to attach the markers (8) to the real stone (4) cast of the dental arches in such a way as to define a tracking (17) system; the means to apply (7) to the patient the same tracking (17) system as attached to the real stone (4) cast of the dental arches; a three dimensional scanner (12) to make three dimensional scans of the surfaces of the real stone (4) cast of the dental arches with the tracking (17) system so as to obtain a virtual (18) reproduction of the teeth and/or the dental mucosa including the tracking (17) system; equipment (13) to make a three dimensional computed tomography in order to generate a virtual (19) three dimensional reproduction of the skull including the tracking (17) system; a three dimensional printer (14); a computer (11) that can be connected to the equipment (13) necessary to make a computer tomography scan, to the three dimensional scanner (12), and to the three dimensional printer (14); a software (15) for graphic purposes to integrate the virtual (19) three dimensional reproduction of the skull with the virtual (18) reproduction of the teeth and/or the dental mucosa so as to superimpose the image of the tracking (17) system present in the virtual (19) three dimensional reproduction of the skull with the image of the tracking (17) system present in the virtual (18) reproduction of the teeth and/or the dental mucosa; a software (16) for planning dental surgery so as to virtually plan the implant, to determine the size and the position of the holes for the support of the same implant, and to generate at least one virtual template guide (2) within the integrated image of the virtual (19) three dimensional reproduction of the skull and the virtual (18) reproduction of the teeth and/or the dental mucosa .