The present invention relates to an arrangement which is used on an anesthetized patient and which, without any input from the patient and with the aid of instruments, ensures correct orientation of a drill template that has been produced from activation of the patient's bite in the conscious state. The template can be formed, for example by means of stereolithography, with retainer sleeves or retainer members for application of the instrument to the template, fastening screws for fastening the template in the oriented position, and also guide sleeves for forming holes intended to extend to the zygoma from a tooth prosthesis produced by means of the template.

The invention also relates to an instrument for a drill template for forming holes for anchoring screws that can be secured in the zygoma.

In connection with dental installation of tooth prostheses which are to be secured in the zygoma, there are strict requirements for the fastening screws of the tooth prosthesis to be assigned ^' exact positions in their longitudinal extent. The space available for this securing is limited and is situated in close proximity to the internal area of the eye. For the tooth prosthesis to be securely anchored, it is important that the screws are secured in solid parts of the zygoma. It is also important that the screw is not allowed to penetrate into the respective orbital cavity. There is also a requirement that the dental installation procedure can be carried out as a single treatment procedure, which requires, among other things, clearly defined and safe installation methods and equipment and accessories for the installation. The invention is intended to solve the above problems inter alia.

What can principally be regarded as characterizing an arrangement according to the invention is that the instrument is designed to extend from a respective retainer sleeve out of the patient's mouth to a position on the outside of the zygoma, and in that the instrument is designed, by means of an indicator of the hole depth, to indicate the end of the respective drill hole at the outside position for markings. The invention is additionally characterized in that, upon application of the template in the anesthetized state of the patient, without bite activation, suitable application of the instruments permits adoption of the correct orientation by locating a position for the template where the instrument is oriented with the respective marking. In a further development of the inventive concept, one and the same template is assigned two instruments, one for each side of the zygoma. Each side of the zygoma can be assigned two drill holes and two fastening screws. In one embodiment, the retainer sleeves and guide sleeves for each zygoma side are arranged in template parts raised above the remaining inner extent of the inside of the template, and the template part for the first side of the zygoma is displaced in relation to the template part for the second side for the purpose of making free access for instruments and drills for both sides.

An instrument having the features characteristic of the invention is designed, in a position assigned to it on the drill template, to indicate the bottom positions of the holes on the outside of the patient in an indication phase effected in the patient's conscious state. A further characteristic is that, in a subsequent orientation phase, in the same associated position on the drill template, the instrument indicates the correct orientation of the drill template in the patient's anesthetized state by acting on

(tilting, displacing, etc.) the template.

Further developments of the novel instrument are set forth in the subsequent dependent claims.

By means of what has been proposed above, it is possible to use computer support and to identify structures on the template, zygoma, etc., and identify effective fastening points in the zygoma at a distance from orbital cavities and nerves. Remaining teeth, palate, jaw bone, gum and other structures in the oral cavity can also be identified, and an effective drill template can be produced and tested out on the patient when the latter is in a conscious state. The markings can be placed on the skin at the locations of the identified fastening points when the patient is conscious and is able to make bite movements when the template is being tested out. The arrangement and the instrument also mean that the markings can be located by the instrument through tilting or orientation to the correct position of the template when the patient is anesthetized and is not able to cooperate, for example with bite movements, information, etc. The template can also be formed with guide members which are activated when the template adopts the correct orientation.

A presently proposed embodiment of an arrangement and of an instrument will be described below with reference to the attached drawings, in which:

Figure 1 shows from the front, by means of a model of the zygoma, a drill template applied in the mouth of a partially indicated patient, two instruments being connected to the template applied in the oral cavity and extending out from the corners of the patient's mouth,

Figure 2 shows the template and the arrangement according to Figure 1 from underneath,

Figure 3 shows the template from underneath, with guide sleeves and retainer sleeves,

Figure 4 shows the structure of the instrument in a horizontal view,

Figure 5 shows the instrument according to Figure 4 in a vertical view, and

Figure 6 shows the instrument according to Figures 4 and 5 in a perspective view.

In Figure 1, parts of a patient are indicated by 1. The patient's zygoma is indicated by 2. In Figure 1, a manually produced plaster model is also indicated and is here designated by reference numbers 3, 4. The drill template is designated by reference number 5, and a filler part which belongs to the drill template and which is used to simulate the mouth situation is indicated by 6. In accordance with the invention, the drill template is intended to permit the formation of holes for fastening screws 7, 8 and 9, 10 on each side of the zygoma. The holes formed using the template thus extend from the drill template (see Figure 2) to solid parts 2a and 2b on the zygoma. The direction of screwing for the various screws is established by means of the drill template. In the figure, the direction of screwing for the screw 8 has been indicated by 8' . The plaster models 3, 4 are produced in a conventional manner. The drill template 5, 6 is produced in computer-aided equipment by what is called stereolithography, which is already well known and will therefore not be described in any more detail here. For each side of the zygoma, a respective instrument 11, 12 is used, which will be described in more detail below. With the aid of the instrument, markings can be placed on the skin of the patient 1. Said markings are designated by reference numbers 13, 14 for the screws 7 and 10, respectively. The template is also provided

with a number (for example four) of fastening screws 15, 16, 17, 18. The drill template 5, 6 is tested out with the patient 1 in a conscious state, and members located on the instruments 11 and 12 can be used to indicate the final positions, for example 19 and 20, for the holes formed in the zygoma. Said indication can involve forming said markings 13 and 14, for example with a felt-tip pen, plasters, etc. After being tested in the patient's mouth, the drill template can be removed and subjected to further working, for example adjustment work. The patient is anesthetized thereafter, and the drill template with applied instruments is thereafter applied in the patient's mouth when the patient is considered to be in an anesthetized state. With the aid of the instruments applied in the same positions in relation to the drill template, the drill template can thereafter be applied to its correct position by the instruments indicating the markings in question. There is therefore no risk of the drill template being set obliquely in the mouth in a condition in which the patient cannot then cooperate in the installation. When the orientation reached by means of the instruments has been obtained, the drill template can be made secure in the oral cavity/jaw bone with the aid of the fastening screws 15, 16, 17 and 18. The drilling of the holes can then take place, and the arrangement and instruments guarantee that the direction established in the computer-aided equipment can be maintained.

Figure 2 shows the arrangement and the instruments according to the figure from underneath. The arrangement includes a retaining (mastication) compound of a type known per se. Corresponding structures are also shown as in Figure 1. It will be seen for example that the fastening screw 7 extends from the drill template 4. Supporting members for the instruments are indicated by 22 and 23, respectively. The bottom of the hole for the screw 9 is also indicated here by 20, and

a marking on the patient's skin on the outside of the zygoma has also been indicated by 2b.

Figure 4 shows the inside of the drill template 4. This shows supporting members or retainer sleeves 24, 25 for the instruments. It also shows parts 26, 27, 28 for anchoring the retaining screws (15, 16, 17, 18 according to Figure 1) . Holes for guiding the drills are indicated by 29, 30. The retainer sleeves 24, 25 and the holes 29, 30 are arranged on a raised part disposed on the inside 4a of the template part or on template part 31. A corresponding template part or raised part is present for sleeves and hole indicators for the second instrument and the holes. This template part is not shown in the figure but can be displaced so that the instruments and drills do not obstruct one another in the installation work.

Figure 4 shows the structure of the instrument . The instrument comprises a first part 32 and a second part 33 which is angled in relation to the first part by a first angle α/ . Said angle assumes values in the angle range of 110-150° and, in the example shown, is ca . 130°. The second part 3 comprises a slide 34 which is arranged to be longitudinally displaceable in the direction of the arrows 35 on the second part. The slide 34 in turn bears a third part 36 which is arranged to be longitudinally displaceable in the slide in directions 37 extending substantially at right angles to the direction of movement 35 of the slide. The second part can have a length scale 38 on one or both of its sides. The third part is provided with a conically tapering front part 36a via or with which the end of the drill hole in question is indicated. Information on the hole length has been obtained in conjunction with the computer-aided production, and the slide 34 can be adjusted to this obtained value. The first part 32 is provided with a supporting member 39 in the form of a guide sleeve or guide pin which is

adapted to the retainer sleeve 24, 25. The longitudinal axis of the sleeve 39 is indicated by 39a, and the longitudinal axis of the sleeve extends in relation to the longitudinal direction of the first part at an angle α/ ' which is preferably ca. 60°, but can be in the range of 50-70°.

Figure 5 shows the configurations of the parts in a vertical section that has been turned through 90° in relation to the horizontal section according to Figure 4. Figure 5 shows the presence of a manual actuation member 40 by means of which the slide 34 can be locked onto the second part 33 in different longitudinal displacement positions. The actuation member 40 is also intended to allow the longitudinal displacement position of the third part 36 to be locked in relation to the second part 33.

Figure 6 shows a perspective view of different parts of the instrument and their mutual positions. The parts 33 and 36 are arranged with longitudinal depressions so that they can be locked onto one another by means of the actuation member 40 which, when screwed down, presses the bottom part of the part 36 against the top part of the part 33 so that the slide 34 is locked onto the part 33 and the part 36 is locked onto the slide

34. _. The instrument parts can be locked in their positions on the template during the displacement between said states. The drills/holes can be made continuous, and the drill tips can be seen through the skin.

The invention is not limited to the embodiment described above by way of example, and instead it can be modified within the scope of the attached patent claims and the inventive concept .