This application claims priority from European Patent Application Serial No. 09176456.3, filed Nov. 19, 2009.
The invention relates to a method and system for designing a dental restoration, and in particular to a method and system for designing a dental restoration of a type comprising a dental implant and a dental abutment receivable on the implant.
A dental restoration is typically used to replace part of a natural tooth or even one or more entire natural teeth in a patient's mouth. A replacement of an entire tooth typically comprises a super structure, like a crown or a bridge, which typically is designed to resemble visible parts of a natural tooth. The tooth replacement typically further comprises a dental implant by which the replacement can be anchored in a patient's jaw. In many cases the super structure is connected to the dental implant via an abutment. Therefore such an abutment typically has an interface to the implant as well as a further interface to the super structure.
The dental implant is typically an elongated pin or screw which is inserted in a patient's jaw by surgery. After insertion the implant typically has to heal into the patient's jaw before the abutment and the super structure are placed on it. Typically the dental implant has a certain inclination angle in the patient's jaw to fit the anatomic situation in the patient's mouth, like for example the geometry of the gums and the jaw and their position relative to one another. On the other hand the super structure and/or the abutment may have to be angularly aligned to adjacent teeth so that the visible part of the final dental restoration is generally inline with such teeth. The angle required to fit with adjacent teeth may however be different from the angle of the implant. The abutment therefore may also provide for compensating such an angular offset.
To make the dental restoration fit nicely with adjacent teeth in a patient's mouth the abutment and/or the super structure is/are typically prepared by help of a physical model of the patient's teeth. Such a physical model typically also reproduces at least part of the inserted dental implant, for example an interface of the implant which is supposed to receive the abutment. Therefore a dental technician, for example, may physically shape and fit the abutment and/or the super structure into the desired place at the model.
The abutment and/or the super structure may also be prepared by using a CAD/CAM technique. In such a technique the shape of the physical model is typically captured by an optical measuring device. The so obtained computer model may then be used to design and manufacture the abutment and/or the super structure by computer aid. For the design of the abutment the shape of the implant interface is typically required in the form of computer data or a computer model. There are a variety of different implants on the market having dedicated uniquely shaped interfaces. Accordingly the implant manufacturers normally also provide computer models of at least the interfaces of their implants.
On the other hand in addition to the shape of the interface the actual position of the interface relative to other teeth in a patient's mouth is usually required to design the abutment and the super structure properly. For example the abutment and the super structure are usually designed to not only match with the interface of the implant, but also such that visible parts of the final dental restoration are positioned well inline with adjacent teeth.
In particular the inclination angle of the implant can typically not be provided by the implant manufacturer, but must be determined at the actual situation in a patient's mouth or at the physical model of the patient's teeth. To determine the inclination angle of the implant a measuring element is typically used. The measuring element is typically received on the interface of the implant and subsequently captured by the optical measuring device, like for example a three-dimensional scanner. The measuring element is typically shaped, for example elongated, such that its inclination angle can be determined from the captured shape. Some measuring elements also have a structure which indicates a rotational orientation, for example for use with implants having interfaces that require rotational positioning of the abutment to be received.
The inclination angle and eventually the rotational orientation are typically required to appropriately position the computer model of an implant interface on a CAD system so that further parts of the dental restoration can be designed based thereon.
In summary the implant manufacturers typically have to provide data about the shape of the implant, data about the measuring element, and physical measure elements. On the other hand dental labs which use CAD/CAM methods for making tooth replacements based on several implant types typically purchase and maintain data libraries holding data about different implant types and measuring elements, and typically keep a stock holding a variety of physical measuring elements. Further the dental labs typically determine the inclination angle (and eventually the rotational orientation) of the implant in addition to capturing the situation in a patient's mouth.
Although these approaches are established in the preparation of dental restorations there is still a need for facilitating the design of a dental restoration using a certain implant of a variety of different implants. It is further desirable to minimize the time period required to provide a dental restoration, and to provide a relatively inexpensive dental restoration that nevertheless has a relatively high quality.
The invention in one aspect relates to a method for designing a dental restoration of a type comprising a dental implant and a dental abutment receivable on the implant. The abutment is adapted to be received on the dental implant and is further adapted to receive a dental super structure. The method comprises the steps of:
For the purpose of this specification a dental abutment as referred to herein is preferably generally adapted for connecting a dental implant and a dental super structure, like a dental crown or bridge, for example.
The invention may be advantageous in that it preferably allows for making a physical model of an abutment, for example a wax-up, unnecessary because the invention preferably enables a combination of a user-defined implant surface representation and a predetermined abutment model. The invention may further be advantageous in that it may make a measuring element for determining an implant inclination angle and/or an implant rotational orientation unnecessary in the preparation of a dental restoration. Further the invention may facilitate the preparation of a dental restoration based on one of a variety of different dental implants. In particular besides the presence of a physical implant or part thereof further information about the implant may not be required for the preparation of the dental restoration. The invention may further not require a determination of an inclination angle of the dental implant in a patient's mouth. Because the determination of the inclination angle may be omitted, tolerances resulting therefrom are preferably avoided so that the invention may help maximizing the precision of the dental restoration. The invention may further generally help minimizing efforts in the preparation of a dental restoration, and may provide for a relatively inexpensive dental restoration.
In one embodiment the method further comprises the step of using a computer representation (D′) of an inner super structure surface (D) to provide a computer representation (C′) of an outer abutment surface (C). The method may further comprise the step of providing the predetermined abutment model with the implant receiving surface representation (B′) and the outer abutment surface representation (C′) to provide the user-adapted abutment model. Thus the user-adapted abutment model may be provided with the implant receiving surface representation (B′) based on the implant surface representation (A′), and optionally in addition with the outer abutment surface representation (C′) based on the inner super structure surface representation (D′). The outer abutment surface representation (C′) may however also be part of the predetermined abutment model, and may remain generally unchanged.
Further the method may comprise the step of modifying the outer abutment surface representation (C′) and/or the implant receiving surface representation (B′) with computer aid. The method may also comprise the step of modifying the predetermined abutment model and/or the user-adapted abutment model with computer aid. Therefore the invention is advantageous in that it may provide for a rapid design of an abutment model, but may in addition enable a user modification of the predetermined abutment model.
In one embodiment the method may comprise the step of capturing a surface (A) of the dental implant to provide the user-created implant surface representation (A′). The user-created implant surface representation (A′) may be obtained from measuring a surface of a physical dental implant, for example from optically or mechanically scanning a surface of a physical dental implant. Such a physical implant may be an implant analog, for example, which resembles an implant which is insertable or inserted in a patient's mouth. However for better clarity it is generally referred to an “implant” in this specification although in some instances an implant analog may be used instead of an actual implant. Further the method may comprise the step of storing the user-created implant surface representation (A′) as reference implant surface representation (A″) in a database. Such a reference implant surface representation (A″) may thus be maintained available for further use so that a new capturing of a dental implant may be avoided. This may help minimizing time and costs in the preparation of the dental restoration.
The method may further comprise the step of determining at least one of an inclination angle and a rotational orientation of the dental implant. Although such a method step may be made unnecessary by the invention, the invention may still allow the determination of the inclination angle and/or the rotational orientation of the dental implant. Thereby the compatibility of certain CAD software operating according to a prior art method may be maintained. For example software configured to comply with a method requiring information about the inclination angle and/or the rotational orientation may still be supported by the present invention.
In one embodiment the method further comprises the step of matching the user-created implant surface representation (A′) with at least one reference implant surface representation (A″). The reference implant surface representation (A″) may for example be retrieved from a database storing a plurality of different predetermined implant surface representations. Further the appropriate reference implant surface representation (A″) may be identified from comparing the user-created implant surface representation (A′) with at least one of the reference implant surface representations, and from selecting the reference implant surface representation (A″) which matches the user-created implant surface representation (A′) best, for example in shape. The appropriate reference implant surface representation (A″) may further be selected from a database by a user, for example by user input of certain information about the dental implant, like for example the type and/or the manufacturer.
In another embodiment the method comprises the step of conforming the user-created implant surface representation (A′) at least partially to the reference implant surface representation (A″). Thereby the precision of the user-created implant surface representation (A′) may be increased. Further this may allow for capturing the user-created implant surface representation (A′) at a relative low precision (for example relatively low scan resolution) and increasing the precision subsequently. Thus a less complex measuring device may be used and/or less measuring time may be required for capturing the user-created implant surface representation (A′). The method may further comprise the step of using the predetermined implant surface representation to determine the inclination angle and/or the rotational orientation of the dental implant. This may be performed, for example, by determining the inclination angle and/or the rotational orientation of the user-created implant surface representation (A′) relative to the reference implant surface representation (A″). Thus the inclination angle and/or the rotational orientation may be determined from comparing the alignment between two structures rather than from deriving the inclination angle and/or the rotational orientation from only one structure itself. This may provide for a relatively precise determination of the inclination angle and/or the rotational orientation.
In one embodiment the abutment model may be retrieved from a database holding a plurality of different abutment models. The abutment model may be selected by a user, for example. Therefore a user may provide information about the dental restoration, for example the type of tooth to be restored (front tooth or side tooth, for example), and this information may be used to retrieve the appropriate abutment model.
The abutment model may then be provided with the implant receiving surface representation (B′). The method may further comprise the step of replacing a predetermined implant receiving surface representation that is associated with the abutment model. The predetermined implant receiving surface representation may in particular be replaced by the implant receiving surface representation (B′) which is based on the user-created computer representation (A′). For example the abutment model may be provided by an implant manufacturer, and the abutment model may comprise a predetermined implant receiving surface representation belonging to a certain implant of this manufacturer. And the invention preferably allows replacing this predetermined implant receiving surface by a customized one.
In a further embodiment the implant receiving surface representation (B′) may be provided without a determination of an inclination angle and/or the rotational orientation of the dental implant being required or performed. Thereby the determination of the inclination angle and/or rotational orientation may be made unnecessary.
In one embodiment the method further comprises the step of providing an outer super structure surface representation (E′) of the super structure. Such a surface may be designed to fit a certain situation in a patient's mouth. The method may further comprise the step of creating a computer model of the super structure based on the inner and outer super structure surface representations (D′, E′). The outer super structure surface representation (E′) and the creation of the super structure model may be performed on a CAD system for example.
In one embodiment the user-adapted abutment model and/or the super structure model are used to create machine instructions for machining the abutment and the super structure. Further the method may comprise the step of machining the abutment and the super structure. Machining may comprise material removal (like milling or grinding for example) or material build-up (like laser sintering or 3D printing for example.
In one embodiment the method comprises the step of providing a dental implant link which is adapted to be received on a dental implant base. For the purpose of this specification the term “implant base” refers to the part of the dental restoration which is typically used for anchoring the dental restoration in a patient's jaw, although the same part may also be simply referred to as “implant” in dentistry. Further for the purpose of this specification the dental implant link and the dental implant base, when combined, may be referred to as “dental implant”, although in dentistry the dental link may sometimes be referred to as a part of an abutment. Accordingly the dental implant link together with the implant base may form the dental implant.
A further aspect of the invention relates to a system for designing a dental restoration of a type comprising a dental implant and a dental abutment receivable on the implant. The system is adapted for:
In one embodiment the system is adapted for using a computer representation (D′) of an inner super structure surface (D) to provide a computer representation (C′) of an outer abutment surface (C), wherein the system is adapted for providing the predetermined abutment model with the implant receiving surface representation (B′) and the outer abutment surface (C′) to provide the user-adapted abutment model.
In a further embodiment the system is further adapted for modifying the outer abutment surface representation (C′) and/or the implant receiving surface representation (B′) with computer aid.
In still another embodiment the system is adapted for modifying the predetermined abutment model and/or the user-adapted abutment model with computer aid.
Thus the system is preferably generally adapted to perform the method of the invention. Features of the method of the invention therefore may also be features of the system of the invention.
In one embodiment the system comprises a database holding a plurality of predetermined abutment models. The system may further comprise an interface for receiving the user-created surface representation (A′) of the dental implant. Therefore the system of the invention may enable the preparation of a dental restoration based on a physically available dental implant and/or dental link and otherwise independent from information or materials from the implant manufacturer. On the other hand the system thus may allow for the preparation of a dental restoration using predetermined abutment model. Therefore the user-adapted abutment may also be created relatively rapidly.
The method of designing a dental restoration according to the invention may generally comprise steps of capturing a situation in a patient's mouth, and further steps of designing and manufacturing dental restoration components for fitting the situation in the patient's mouth. The situation in a patient's mouth may for example be captured from a plaster model which is casted from an impression of the patient's teeth or directly from the patient's mouth by optically scanning, for example. The so captured situation may then be used as a basis for designing components of the dental restoration.
For better understanding the dental restoration is described in its configuration first, and subsequently the method of the invention is described by way of an example.
In the example shown in
The head structure 13 has an abutment 3 and a super structure 4. In the example the super structure is a dental crown (for restoring one tooth), however may in another example be a bridge (for restoring two or more teeth). The abutment 3 has an outer abutment surface C which is adapted to receive the super structure 4. Accordingly the super structure 4 has an inner super structure surface D fitting with the outer abutment surface C. For example the inner super structure surface D and the outer abutment surface C may generally correspond in shape with one another. Further the inner super structure surface D and the outer abutment surface C may be scaled proportionally relative to one another. Thus the inner super structure surface D and the outer abutment surface C may be shaped such that a bonding layer can be arranged between. The bonding layer may for example have a generally uniform thickness, or may taper off toward its outside boundaries. Such a bonding layer may for example comprise a dental luting cement. The super structure 4 may further comprise a framework and a veneering (not shown in detail). In this case the framework may be basically a supporting structure for providing a certain mechanical stability for the dental restoration, whereas the veneering may provide for pleasing aesthetic characteristics.
The dental restoration 1 further has a screw 14 for mounting the link 5 onto the implant 12. In the example shown the dental restoration 1 is adapted such that the screw 14 can extend through the abutment 3 and the link 5 into the implant base 2. In particular the abutment 3 and the link 5 each have a through hole through which the screw 14 can extend. Thus the link 5 may be affixed to the abutment 3 first and the so formed assembly may be subsequently secured on the dental implant 12.
A method in the preparation of the dental restoration according to an embodiment of the invention is described in the following. The implant 12 may be standardized and made available to dentists for use in a patient's mouth. Further the head structure 13 may be individually prepared by a dental lab to fit a certain situation in a patient's mouth as well as a certain standardized implant. The implant 12 and the head structure 13 may then be merged, for example by the dentist, to form the dental restoration.
The method step may further comprise matching of the user-created implant surface representation A′ (shown in
The reference implant surface A″ may further be stored on a computer, for example in a database for further use.
The database 200 may be used for matching of the user-created implant surface representation A′ with a reference implant surface representation retrieved from the database 200. For example an appropriate reference surface representation A″ (not shown) may be identified in the database based on a comparison of the implant surface representation A′ with at least one reference surface representation contained in the database 200. The reference implant surface representation A″ which matches the implant surface representation A′ best may then be proposed to a user who can accept or reject the predetermined implant surface representation A″ for further use. The implant surface representation A′ may therefore be captured at a relatively low precision (for example relatively low resolution and/or relatively high tolerances) but at a precision sufficient to select a more precise reference implant surface representation A″ from the database. This may minimize the time, and further may allow using a relatively inexpensive measuring device, for capturing the implant surface representation A′.
The reference surface representation A″ may further be selected by a user, for example by user input of date about the dental implant (for example implant type, and/or implant manufacturer). The computer may therefore have a user interface via which such data can be entered, for example via keyboard, by a data carrier, via a data capturing device, like a bar code or RFID reader, or in any other appropriate manner. The so identified reference surface representation A″ may be then retrieved and used in the matching as described and illustrated under
So the so created user-adapted abutment model 3″ may then be used for designing the dental super structure as illustrated in
Number | Date | Country | Kind |
---|---|---|---|
09176456.3 | Nov 2009 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/US10/56962 | 11/17/2010 | WO | 00 | 7/31/2012 |