DE19629708A1 - Method for pre-operative planning of teeth implants, to establish drilling coordinates in jaw - Google Patents

Abstract

The method uses a mould made respectively for upper and lower jaws, having cupped trays (3) arranged on the moulds, which are then put in an articulator. The trays are positioned with the interposing and securing of a metal arc (4) of a bite fork (5). The moulds are then removed from the articulator and with trays and bite fork are fixed in a base unit. The bite fork is spatially oriented according to the acquired primary data. The primary data is entered in a computer which establishes the complete implant coordinates based on the primary data of the native jaw. The complete coordinates of the clamped upper or lower jaw tray are determined in a NC positioning system, and entered in the computer. The primary data and the tray coordinates are calibrated in the computer and the implant coordinates are transferred to the NC system, across an interface. Drilling sleeves are then positioned and fixed using the NC positioning system at the tray according to the established implant coordinates.

Description

The invention relates to a method for preoperative planning of Dental implants and the establishment of drilling coordinates in the jaw by the computer-aided evaluation of primary data from imaging Structural examinations of the bones in the upper and lower jaw and the Implementation of the determined coordinates in a drilling template for Preparation of the implant site.

The permanent implantation of superstructures on endosseous implants on partially edentulous or edentulous jaws requires careful Alignment of the implant bed in the real anatomical situation, especially with regard to the positioning of the bone holes for the implants taking into account the given amount of bone. DE 43 28 490 A1 describes a method and for preoperative planning a device for determining the position and preoperative alignment of endosseous implants in the jawbone using Information from computer tomography (CT) recordings and for setting of the jaw holes for the implants depending on the intended prosthetic solution and the available bone available. in the Individuals then use the known method to start with the reconstruction an ideal prosthetic restoration on a scale of 1: 1, in which starting from a wax model, first a plastic splint is manufactured. In this row of teeth replicated in this way Consideration of the individual manufacturers for their implant systems given distances in the central fissure in the occlusal surface  or oro-facial filled with X-ray contrast medium in the middle of the tooth Marking holes introduced. Based on CT images of the in CT plastic splint used in implant position are x-ray Primary data recorded, which takes into account the existing Should allow bone ridges of the alveolar ridge in the implant area. To determine the optimal positioning of the jaw holes using the Primary data is still suggested, by adding to the existing one Bone matched inclination optimized drilling coordinates specify.

The inclination angle determined on the computer using the CT images are measured using a parallelometer based on the in X-ray contrast marking holes in the tooth center Plastic rail inserted. In this way, a drilling template for Are made available, which - used in implant position - as Guide device for the drill when drilling the jaw holes should be used.

An advantage of the above, from a 1: 1 plastic reconstruction prepared drilling template results from the fact that the milling cutter when setting the jaw bores receive a certain amount of guidance and thus the Successful implantation does not depend solely on the. Skill of the treating surgeon. However, there are fundamental weaknesses compared, which relativize the advantages: The acquisition of primary data the CT is complex and represents a relatively complete one Primary data set available. Still is in the process described above the handling of this primary data is problematic because the reference level of the CT scan, from when implementing the inclination in the parallelometer is assumed, on the computer, but essentially manually he follows. Systematic incorrect inclination can occur whereby in the extreme case an irreparable therapy situation can occur.

Another disadvantage is that of systematically fixed Distances of the holes in the implant is assumed. By on this way, predetermined lateral orientation of the bores or  Screws with respect to the jaw remain to adapt to the existing one Bone supply only the variable inclination by one by the respective Inclination axis going to the center of the tooth. Except that none Change of position of the implant body according to mesial / distal or labial / oral, For example, if there is insufficient bone, one is Adaptation taking into account anatomical structures, such as Nerve canals, maxillary or paranasal sinuses, etc., practically impossible.

The previously known method attempts these uncertainties through the Proposal to take into account, the holes open semi-circular train to provide surgeons with intraoperative correction options to be kept open. However, this causes the drilling template to lose its actual shape Function.

This results in the object of the invention, a method available to ask which is based on the specific anatomical situation, d. H. the available bone, and under free Positionability of all implant coordinates an exact implementation of the Allows drilling coordinates in the drilling template.

To achieve this object, the invention proposes a method with the following Process steps before:

• 1. Creation of a model of the upper and lower jaw;
• 2. Creation of deep-drawing rails on the models;
• 3. placing the models in an articulator;
• 4. Attach the deep-drawing rails and insert the Metal bow of a bite fork and its fixation;  
• 5. Remove the models from the articulator and plane-parallel Fixation of the models with deep-drawing rails and bite fork in one Socket device;
• 6. Acquisition of primary data of those fixed in the deep-drawing rails native jaw, whereby the bite fork is spatially oriented;
• 7. loading the primary data into a computer;
• 8. Determine the full implant coordinates using the Primary data of the native jaw on the computer;
• 9. Acquisition of the complete coordinates in an NC Positioning device clamped upper or lower jaw Deep-drawing rail;
• 10. Load the deep-drawing rail coordinates into the computer;
• 11. Calibration of primary data and deep drawing rail coordinates in Computer;
• 12. Transfer of the implant coordinates from the computer via a Interface to the NC positioning device;
• 13. Positioning and fixing drill sleeves to the deep-drawing rail to the specified position using the NC positioning device Implant coordinates.

The process assumes that plaster models of the upper and Lower jaw.

The plaster models are made using the known method Thermoformed rails made. The plastic material of the deep-drawing rails should with conventional X-ray technology, especially with  Transverse slices, opaque, d. H. be radiopaque. In addition to the additional possibility to use this for calculations in the computer Using a geometric reference can also make the real one non-invasively Mucosal thickness can be determined. In contrast, the thermoformed rail Material in OPG images is not radiopaque.

The plaster models are now placed in an articulator without the deep-drawing rails set.

The thermoformed rails are put on and the metal arch of the bite fork is interposed and fixed with light-curing paste, for example.

The plaster models are removed from the articulator. The Thermoformed rails with the fixed bite fork and the models are composed. Models, thermoformed rails and bite fork are now fixed plane-parallel in a base unit.

The metal bow of the bite fork including the one attached to it Thermoformed rails protrude horizontally from the support column of the bite fork fixed. This support column in turn becomes vertical on a reference level, for example a base plate, both in the recording process for Obtaining the primary data of the native jaw as well as later drilling sleeve positioning using a multi-axis NC Positioning device attached.

Before the primary data is acquired, preference is given to the imaging techniques used matched contrasting markers attached to the deep-drawing rails. X-ray methods are used for example steel balls or glued, thin metal strips. At other methods, for example nuclear magnetic resonance (MRI) appropriately suitable contrast agents are used. These markers are used all the identification and assignment of individual transverse sections to corresponding OPG.  

After the patient with the upper and lower jaw clearly in the bite fork fixed and the thermoformed rail spatially with respect to the insertion point is clearly oriented, the primary data is acquired with a imaging process. Here is an advantage of the invention Procedure that uses both CT scans, conventional X-ray procedures such as transverse sections or orthopantomograms (OPG) or MRI Methods can equally be used to obtain the primary data.

In the next step, the primary data is loaded into a computer. While data directly available in digital form, for example from CT or MRI images or from conventional ones Digital images (OPG, transversal x-rays), with corresponding Software that can be directly processed are in film form existing images are scanned into the computer via a scanner and digitized, which also makes them accessible for further processing are.

Using the appropriate software, which is already on commercially available Personal computers, the ideal implant position becomes interactive fixed, taking into account the existing bone supply is that the implant itself as well as the complete set of coordinates of the Screws, d. H. of the jaw bores are variable. So it is from the real anatomical situation of the patient's jaw, whereby Icons of the implants to be used to scale Original implant can be aligned vertically and transversely as well a lateral shift to the anterior or posterior also at any time is feasible.

The patient's position in the bite fork is a reference plane can be defined at any time using CT or MRI primary data. In the The use of OPG and transversal shots is through the plane Bite fork or the deep-drawing rail when shooting as well as in the Positioning device clearly defined.  

For example, on the plaster models of the upper and lower jaw attached thermoformed rails become one on the work table multi-axis NC positioning device, d. H. one over a corresponding one Interface numerically remotely controllable from the computer Positioning robot, clamped. To do this, either those of the Bite fork detached thermoformed or used on the Plaster models are molded from new, identical deep drawing coupons. In this Position, the deep-drawing rail coordinates are completely recorded, for example via a CCD camera with digital data conversion, and also loaded into the computer. For the clear definition of all Coordinates is an occlusal view of the corresponding one Plaster model of a deep-drawn rail sufficient. The deep-drawing rail Coordinates are also digitized and read into the computer.

Starting from the insertion point of the deep-drawing rail when the Primary data used in the positioning device as the coordinate zero point is set, the primary data is calibrated with the Deep-drawing rail coordinates in the clamping device of the Positioning device.

After defining all implant coordinates, i.e. H. the unique spatial orientation of the jaw holes, the position data transferred to the NC positioning device via an interface. In it on the deep-drawn rails clamped together with the plaster model Precisely positioned drilling sleeves within the scope of the manufacturing accuracy fixed, the through hole in terms of positioning and Orientation exactly according to the jaw holes determined on the basis of the primary data corresponds.

Due to the reproducible fixation of the patient with the bite fork in the imaging recording process and the coordinate acquisition of the Plaster model together with the deep-drawing rail in the positioning robot the method according to the invention offers for the first time the possibility of To uniquely relate coordinate sets in the computer, d. H. to calibrate and with it the uncertainties of manual manipulations involved in  previous procedures are inevitable in principle to circumvent. To this In this way, the surgeon receives a drilling template that is lossless Implementation of those obtained using the imaging method Allows information.

An advantageous development of the method according to the invention provides that before the acquisition of the primary data the following procedural steps be performed:

• a. Attachment of optical fibers to the deep-drawing rails in the Area of the implant positions, their light exit openings are directed facial or anterior;
• b. Fixing the jaws in the deep-drawing rails;
• c. Irradiation of intense light, preferably laser light, into the Light entry openings of the optical fibers;
• d. Adjustment of the X-ray machine to those visible from the outside Spots of light that pass through the soft tissue facial to the Face of the patient are projected.

By connecting the optical fibers to a laser pointer, for example are connected, the intense points of light through the Soft tissue on the patient's face is clear and sharp from the outside bounded recognizable. For example, on these light markings X-ray device for transverse sectional images precisely adjusted. To this This ensures that the transverse cuts are exactly at the desired implant positions can be performed. The optical fibers are, for example, with small metal rings on the deep-drawing rails glued, whereby the metal rings in turn have a function as X-ray Markers can meet the unique assignment of the transverse sections enable to the OPG.  

The drill sleeves in the positioning robot are expediently d. H. the positioning device, glued to the deep-drawing rail. By using a post-curable adhesive, For example, a light-curing adhesive, the drill sleeves can be used fixed force-free with a small drop of adhesive on the deep-drawing rail will. This can be done, for example, according to the process of actual drilling sleeve positioning the positions on the deep-drawing rail be scanned and small, light-curing adhesive spots are set be, which makes the adhesive particularly economical to use. A fast and secure fixation of the drill sleeves is achieved by the Glue point after placing the drill sleeve by irradiation with concentrated UV light, for example through an optical fiber, immediately is cured. This will prevent accidental slipping effectively prevented.

Since the drill sleeves themselves are small and light, the Positioning device only needs to be sufficiently accurate however, not being able to transfer large forces. For example the conversion of a plotter is conceivable, only by one or two additional inclination axes is expanded.

If OPG recordings are preferred, it is advisable if the positioning robot of the motion curve of the used X-ray device follows. This makes it particularly easy to set up are and must essentially implement the determined inclinations can.

The fact that the drill sleeves in the area of the glue point, d. H. of Glue drop, before sticking with a stopper from light machinable material are sealed, it is ensured that the Milling cutter for setting the jaw holes not through remnants of the hardened Adhesive is hindered, but only the easily machinable plug must penetrate.  

The method according to the invention is decisive through a device relieved, in which the deep-drawn rails of the upper and lower jaw in the are attached to the arc of a bite fork in the manner described above. Thereby is the clear position fixation of the patient already with the acquisition which enables primary data. This is an essential requirement that later the unambiguous assignment of the primary data to the Gypsum model coordinates, i.e. H. to the positioning device passed implant coordinates can take place.

The adjustment of a transverse x-ray device according to claim 5 is preferably carried out with a deep-drawing rail on which optical fibers are attached are, the light exit openings are directed facially or anterior and whose light entry openings are connected to a laser. The laser Light points enable exact positioning of the transverse X-rays and largely avoid the risk of being wrong placed X-ray sections. On the one hand, this eliminates the need the patient through a variety of x-rays with relatively high Radiation doses, on the other hand, reliable data is immediately available the positioning of the jaw holes.

The drill sleeves expediently consist of titanium. Titan has namely the advantage of having excellent material properties and moreover to be absolutely biocompatible, which means that there is hardly any risk of infection, if abrasion or the like should get into the jaw bore. This Risk can be minimized in that the drill sleeves at least in the Inside the bore with a hard, wear-resistant coating are provided, for example surface nitriding or carburization.

The method according to the invention is described below with reference to the drawings explained in more detail:

The individual shows:  

Figure 1 is a pair of plaster model with deep-drawing rails in the base device.

Fig. 2 is a bite fork according to the invention having deep draw rails;

Fig. 3 is a detailed view of Fig. 2;

FIG. 4 shows a patient skull fixed in position in the bite fork according to FIG. 2;

FIG. 5 shows a dialog box the planning software;

Fig. 6 is a side view of a positioning device according to the invention;

Fig. 7 is a cross section of a drilling template according to the invention.

In Fig. 1 a perspective view is shown how in each case a plane-parallel plaster model 1 a and 1 b from the upper or lower jaw to each other in the vertical direction displaceable clamping plates of a base unit 2 are clamped. On the plaster models 1 a and 1 b there are already deep-drawn rails 3 created individually from plastic film.

Fig. 2 also shows in perspective view how the deep-drawing rails 3 of a bite fork total provided with the reference numeral 5 are mounted on the metal sheet 4. The metal arch 4 is fastened to a column 6 of the bite fork 5 , which is oriented perpendicularly with respect to a base plate 7 .

Optical fibers 8 are attached to the deep-drawing rails 3 , the light exit openings of which are directed towards the facial or anterior in the region of the implant positions and are connected to a laser pointer 9 with their light entry openings.

FIG. 3 shows a detailed view of a deep-drawing rail from FIG. 2 on the light exit openings of the optical fibers 8 . These are glued in the area of the implant position with metal rings 10 , which can be used, for example, to identify and assign transverse cuts to the corresponding OPG. In addition, 3 metal markers 11 are glued onto the deep-drawing rail, which have lead strips glued onto thin plastic film, for example.

The deep-drawing rails 3 are attached to the metal arch 4 in a defined orientation by being placed on the plaster models 1 a and 1 b of the upper and lower jaw in the base unit 2 , the metal arch 4 is coated with - preferably light-curing - adhesive and is inserted occlusally between the plaster models 1 a and 1 b with the deep-drawn rails 3 attached. Then the plaster models 1 a and 1 b are moved together in parallel in the base unit 2 until the metal arch 4 is fixed in the functional chewing plane between the deep-drawing rails 3 . After the adhesive has hardened and the optical fibers 8 and the metal markers 11 have been attached, the bite fork 5 is ready for further implementation of the method.

FIG. 4 shows how a patient's skull 12 is fixed in position in the deep-drawing rails 3 of the bite fork 5 for data acquisition by means of X-rays or other imaging methods. This schematically indicates how the laser light emitted by the optical fibers 8 generates light spots 13 which are sharply delimited on the skin surface of the patient, to which, for example, the light sight of an X-ray device can be precisely adjusted when taking transversal slice images and thus the cut image can be taken exactly at the marked implant position . The insertion point of the bite fork 5 marks the coordinate zero point.

Fig. 5 shows the dialog window of the planning software on the computer. In detail, an OPG scanned into the computer and digitized is shown in the left window 14 a, while the right window 14 b shows a transversal sectional view. In addition to the anatomical structures, the metal markers 11 are clearly recognizable, which in this case are designed as metal balls and enable a clear position assignment in the OPG and in the transverse section.

In OPG 14 a, the horizontal dashed line denotes the plane defined by the metal arch 4 during the X-ray exposure. The assignment is clear.

The vertical or oblique, lightly dashed lines designate them interactively based on the available bone determined drilling coordinates set using appropriate input devices for the implants.

In Fig. 6 is a positioning device as a whole is designated with the reference numeral 15. This has a table 16 and a positioner 17 , which can be positioned in a computer-controlled manner in all spatial directions and angular tilting.

According to the method according to the invention, a plaster model 1 a or 1 b is clamped together with the thermoformed rail 3 placed on the table 16 . The coordinates of the plaster model 1 a / b are then recorded, digitized and loaded into the computer using a deep-drawing rail 3, for example using a CCD camera, in which the implant positions are determined on the basis of the primary data.

Using the markers 11 , the primary data, for example from OPG and transverse sections, are automatically calibrated in the computer with the plaster model coordinates recorded by the CCD camera 18 . This is done, for example, by also defining the insertion point of the bite fork 5 in the positioning device 15 as the coordinate zero point.

In the next step the specified computer drilling coordinates are passed via an interface to the positioning device 15th This places the drill sleeves 19 on the deep-drawing rails 3 exactly at the predetermined coordinates. The drill sleeves 19 are made of titanium, for example, and are closed at the front with an easily machinable plastic stopper 20 to prevent the penetration of adhesive 21 , which is applied for fixation between a drill sleeve 19 and the deep-drawing rail 3 . Intensive UV light is optionally radiated onto the adhesive 21 through an optical fiber 22 in order to cure it more quickly.

According to the method according to the invention, the deep-drawing rail 3 with the glued-on drill sleeves 19 thus provides an absolutely clear drilling template which is optimally matched to the real anatomical situation in the patient. The guidance of the milling cutter in the precisely positioned drill sleeves 19 allows for the first time a precise implementation of the optimal drilling and implant coordinates in the patient's jaw, which is largely independent of the skill of the surgeon.

Claims (15)

1.Procedure for the preoperative planning of dental implants and for the determination of drilling coordinates in the jaw by computer-aided evaluation of primary data from imaging structural examinations of the bones in the upper or lower jaw and implementation of the determined implant coordinates in a drilling template for the preparation of the implant site, characterized by the process steps:

• 1. Creation of a model of the upper and lower jaw;
• 2. Creation of deep-drawing rails on the models;
• 3. placing the models in an articulator;
• 4. placing the deep-drawing rails and interposing the metal bow of a bite fork and fixing them;
• 5. Removal of the models from the articulator and fixation of the models parallel to the plane with deep-drawing rails and bite fork in a base unit;
• 6. Acquisition of primary data of the native jaws fixed in the deep-drawing rails, the bite fork being spatially oriented in a defined manner;
• 7. loading the primary data into a computer;
• 8. Determination of the full implant coordinates based on the primary data of the native jaw on the computer;
• 9. Acquisition of the complete coordinates of the upper or lower jaw deep-drawn rail clamped in an NC positioning device;
• 10. Load the deep-drawing rail coordinates into the computer;
  11. Calibration of primary data and deep-drawing rail coordinates in the computer;
• 12. Transfer of the implant coordinates from the computer via an interface to the NC positioning device;
• 13. Positioning and fixing drill sleeves on the deep-drawing rail using the NC positioning device on the defined implant coordinates.

2. The method according to claim 1, characterized in that before the acquisition of the primary data marker attached to the deep-drawing rails will. 3. The method according to claim 1, characterized in that the Acquisition of the primary data is carried out using a computer tomograph (CT). 4. The method according to claim 1, characterized in that the Acquisition of the primary data is carried out with a nuclear spin tomograph (MRI). 5. The method according to claim 1, characterized in that the Acquisition of primary data using conventional X-ray imaging technology, especially OPG and transversal slice images.   6. The method according to claim 1, characterized in that the in Image data present primary data scanned into the computer and be digitized. 7. The method according to claim 1, characterized in that the following method steps are carried out before the acquisition of the primary data:

• 7.a. Attachment of optical fibers to the deep-drawing rails in the area of the implant positions, the light exit openings of which are directed facially or anteriorly;
• 7.b. Fixing the jaws in the deep-drawing rails;
• 7.c. Irradiation of intense light, preferably laser light, into the light entry openings of the optical fibers;
• 7.d. Adjustment of the X-ray device to the light spots visible from the outside, which are projected facially through the soft tissue onto the face of the patient.

8. The method according to claim 1, characterized in that the Drill sleeves are glued to the deep-drawing rail. 9. The method according to claim 7, characterized in that the Drill sleeves in the area of the glue point with a plug before gluing be closed from easily machinable material. 10. The method according to claim 1, characterized in that the NC positioning device of the motion curve of the used X-ray device follows.   11. Device for carrying out the method according to claim 1, characterized in that deep-drawn rails of the upper and lower jaw on Bow of a bite fork are attached. 12. Device for performing the method according to Claims 1 and 4, characterized in that on a deep-drawing rail Optical fibers are attached, the light exit openings of which are facial or are directed anterior and their light entry openings to a laser are connected. 13. Device for performing the method according to claim 1, characterized in that the X-ray marker is attached to an adhesive film brought brought metal strips. 14. Device for performing the method according to claim 1, characterized in that the drill sleeves are made of titanium. 15. Device for carrying out the method according to claim 1, characterized in that the drill sleeves at least inside the Bore with a hard, wear-resistant coating.