SAN MATEO, Calif., July 1, /PRNewswire/ -- Sonitus Medical, Inc., a medical device company that manufactures the world's first non-surgical and removable hearing device to transmit sound via the teeth, today announced that it has received an additional FDA . Jun 16, · Tusker is led by CEO Amir Abolfathi, the inventor and founder behind Sonitus Medical and its tooth-conduction hearing aid. Although the Centers for Medicare & Medicaid Services denied reimbursement for the Sonitus device, the company found a new lease on life after the U.S. military adopted the technology. USB2 US11/, USA USB2 US B2 US B2 US B2 US A US A US A US B2 US B2 US B2 Authority US United States Prior art keywords virtual teeth tooth image actual Prior art date Legal status (The legal status is an assumption and is not a legal conclusion.
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If the teeth are scanned directly in the mouth, the relationship of the upper and lower jaw may be recorded by imaging the surfaces of the teeth in both arches at the same time with the patient biting into the CT bit plate. Alternatively, the arches may be separately scanned. If dental casts of the upper and lower jaws are made, a preferred embodiment is to use a cast holder to record the position of the upper and lower dental cast in relation to the CT bite plate.
The casts may be joined to mounting plates that record their relationship to the CT bite plate and the cast holder. The mounting plates may include magnetic or mechanical fixation systems that join the mounting plates to receivers on the cast holder.
Casts can then be removed from the cast holder in a known spatial relationship to the receiver. The casts can then be moved to the imaging system for imaging. Since the data sets for the upper and lower dental cast are known in relation to the mounting plates and cast holder, data sets from the upper and lower casts can be moved in computer space such that the same three-dimensional orientation exists in computer space as existed when the bite plate was in the mouth.
This creates an accurate virtual computer model of the upper teeth and tissues in relation to the lower teeth and tissues in a specific static orientation. The computer models and fixation device should record the form of the teeth and the positional relation of each data set to a high level of precision since patients can feel an object 12 microns thick between their teeth.
The computer model of the upper and lower jaws just described can be very precise but it does not have information about the shape of the bone supporting the teeth or the position of nerve canals and other information obtained using CT.
The present invention solves this problem by imaging the patient's head and jaws with CT using the CT bite plate. The CT data set may be made with the patient biting into the CT bite plate and may orient the data set to three radiographic markers that allow the information to be moved in computer space such that three dimensional data sets for the dental casts or teeth made using non-radiographic techniques are in the same orientation as the CT data set.
Finally, the patient's head can be positioned during the CT scan such that a normal position natural head position or any other diagnostic position can be recorded. This will allow for the precise analysis of the orientation of the teeth to the eyes, face, lips, ears, horizontal or any other diagnostic reference point recorded during the scan. The computer model made using the described invention creates a precise static model of the patient in a specific jaw position. Movement of the computer model can be created by using data from the CT scan to determine the orientation of the upper teeth to the condyles and rotational centers.
This is commonly done in the dental art by using a face bow to approximate the position of the condyles using the ear hole opening as a guide. The actual condyles imaged in the CT can also be used and information about the shape of the condylar fossae may also be a good approximation of movement. This invention also provides for the incorporation of data sets from commercial digital recording devices.
These devices record movement of the lower jaw in relation to the upper jaw and since a static starting point has been recorded with the CT bite plate, it is a simple process to produce motion of the lower jaw model from that point in virtual computer space. Turning now to the figures, FIG.
The bite plate assembly 12 may include a U-shaped rigid section 5 attached to a thin bite surface 13 made of a radiolucent material that mates with the patient's teeth and yet requires minimal opening of the jaws. The bite surface 13 may include a central forward projection 14 that extends between the lips when the assembly 12 is placed in a patient's mouth.
The forward projection 14 may be joined to a vertical portion 15 that, in some embodiments, extends above or below the plane of occlusion. Wings 20 extend laterally from the vertical portion and follow the contour of the face but do not contact it. In this exemplary embodiment, three or more non-linear radiographic markers 25 are attached to the vertical and wing portions of the CT bite plate. These markers 25 have a radiographic density that makes them visible in the CT data and also have a geometric shape that can be imaged with contact, light, laser, or holographic imaging techniques.
Bite registration material 28 may be used to record the indentations 30 of the upper and lower teeth when the patient bites into the CT bite plate assembly In some examples, except for the radiographic markers, the CT bite plate assembly is formed entirely of a substantially radiolucent material.
Accordingly, as described below, images captured by a CT machine may clearly display the radiographic markers 25 while less clearly showing the CT bite plate assembly In some embodiments, the radiographic markers 25 are disposed above or below the plane of occlusion formed by the upper and lower teeth. This may enable better imaging and may reduce the chance of the image of the radiographic markers 25 being skewed by its position relative to other radiographic materials in the mouth, such as dental treatment devices, including fillings, crowns, and braces, among others.
In yet other exemplary embodiments, the CT bite plate assembly may include two or more than four radiographic markers 25 that are disposed above or below the plane of occlusion. The x ray source 48 projects radiation across the patient's head and is detected on a rectangular shaped sensor or detector In this example, the patient's head is positioned in a natural posture in relation to the floor and to the horizontal edge of the detector As the x ray source 48 and detector 50 rotate around the patient, the normal head posture may be recorded in the scan data.
In some exemplary embodiments, the CT machine is a cone beam CT unit. Conventional scanning operations may include orienting the patient's head in a position that is not the natural position. Because the image itself includes no reference points, in order to capture the teeth in a known, reproducable orientation, the patient may be required to hold his head or bend his neck in an unnatural position during capturing.
Then, the physician can make a treatment plan based on the known orientation. These positions, while still allowing capturing of desired spatial relationships between facial features, may not create a realistic image of the patient's natural posture because the head was not in a natural position during scanning, and there is no reference that later tells the physician when the head image is oriented in the natural position.
Accordingly, using the captured images to create treatment plans that involve jaw and teeth displacement may consider the patient's appearance in an un-natural posture, providing an appearance that often differs from the patient's natural appearance. In contrast, scanning the patient's head in a natural position or posture in relation to the floor or in relation to the horizontal edge of the detector may be advantageous when the captured images are used to create a treatment plan affecting aesthetics.
Because the scan is taken with the head in a natural position, the aesthetic position of the teeth, head, eyes, lips, ears, and any other soft or hard tissue can be measured and recorded as the patient would appear to others in social settings, instead of with his or her head tilted back or otherwise placed in an unnatural position.
Thus, the natural position of the head is known relative to the horizontal edge of the detector. While developing a treatment plan, the physician can return the image of the head to the natural position for analysis. Further, because the natural position of the head image is known relative to the horizontal edge of the detector, the image still may be manipulated to positions other than the natural position if desired.
Thus, unlike prior systems that capture images in an unnatural position relative to a fixed reference point, the system disclosed herein may capture images in a natural position relative to a fixed reference point, such as a horizontal edge of the detector. A physician then, while manipulating a CT image, can always return the image to the reference point to return to the natural position.
Recording the CT image is described in more detail with reference to a flow chart, identified by the reference numeral , in FIG. In short, FIG. The process begins with placing or positioning the CT bite plate assembly 12 in the patient's mouth, at a step Here, the bite plate assembly 12 may include the registration material for taking an impression of the patient's upper and lower teeth. At a step , the patient is positioned, with the CT bite plate between his teeth, in a CT machine.
The patient's head is positioned in proper diagnostic alignment to horizontal and to the imaging detector. Accordingly, the patient's head is held in a natural position, rather than an unnatural position.
To position the patient's head, he or she may be instructed to look at a location, such as a mirror or point on a wall, that is disposed relatively horizontally from his or her head. At a step , the patient and the CT bite plate 12 are imaged with computed tomography. If the CT bite plate 12 includes the registration material, then the diagnostic jaw position is recorded with the patient's teeth in the registration material. At a step , a point on each marker is located in 3D computer space.
In some exemplary embodiments, the point on the marker may be the most superior point on the surface of the marker. Other points on the marker may be used with equal success, such as for example, the lowermost point, a side location or a tip of a pointed marker.
At a step , the collected CT data is reformatted to create a volume rendered model of the diagnostic anatomy of the patient. While the collected CT data may be used to create a full model of the diagnostic anatomy of the head and face of the patient, FIG.
In FIG. This scatter makes the CT data set for the teeth non diagnostic. Returning to FIG. At a step , the mandible data is separated from the rest of the computer model, as is shown in FIGS.
This provides the ability to analyze jaw movement and develop a treatment plan consistent with desired jaw movement. Either before or after the CT image is obtained as described in the flow chart , a non-radiographic image of the patient's teeth also may be obtained. Referring first to FIG. The process begins at a step by inserting the CT bite plate 12 into the patient's mouth and imaging the upper and lower teeth and tissue directly in the mouth.
Also at this time an image is taken of a lateral aspect of the teeth and the radiographic markers with the patient biting into the CT bite plate.
These images may be taken using non-radiographic imaging devices, such as laser devices, light devices, or holographic devices to image the teeth. At a step , a data set is created for the top arch and a data set is created for the bottom arch. Each of these data sets also includes data representing the radiographic markers. At a step , the image data of the lateral aspect of the teeth and of radiographic markers may then be used as a reference to move and locate the upper and lower scan data to a correct position in the computer space.
The CT data set and the non-radiographic data set are then brought together. At a step , pixels of the radiographic markers in the CT data set are used as references to move the non-radiographic data sets of the upper and lower teeth and tissues into the same 3D orientation. Finally, at a step , the data sets from the upper and lower non-radiographic imaging are joined to the upper and lower data sets from CT imaging using the radiographic markers as reference points. Joining may be accomplished using Boolean operations and may occur for both the upper teeth set and for the lower teeth set.
Another exemplary process of capturing a non-radiographic image is described with reference to a flow chart, referenced as in FIG. Here, at a step , a dental plaster cast is made of the upper and lower teeth and tissues. These may be made in any conventional manner. At a step , the dental casts are placed in the CT bite plate 12 and the radiographic markers are imaged by a scanning machine.
One example of this is shown in FIG. Here, the radiographic markers are being imaged by a contact digitizer. A closer view is shown in FIG. At a step , the CT bite plate is removed and the upper and lower casts are imaged in the same 3D orientation as was the radiographic markers. Accordingly, the dental casts are imaged relative to the radiographic markers in the CT bite plate Once one of the upper and lower casts is imaged, the other also may be imaged.
Separate imaging of the upper and lower casts enables easier analysis for treatment, as described further below. At a step , image data from the radiographic markers may be used to orient the scan data of the upper and lower casts and move them to correct positions in the computer space. Then, at step , as described above with reference to FIG. At step , the data sets from the upper and lower non-radiographic imaging are joined to the upper and lower data sets from CT imaging using the radiographic markers as reference points.
The cast holder 45 is a mechanical device that has an upper member 32 and lower member 34 that can be separated and repositioned into the exact same orientation. Each cast is also joined to a mounting plate 49 that precisely connects to the upper and lower member of the cast holder with a mechanical or magnetic receiver After mounting the casts in the cast holder, the upper and lower dental casts can be removed and placed in the imaging system.
The digital imaging system can use any number of methods that include laser, light, holographic or contact digitizing to image the dental casts and the CT bite plate. The CT bite plate and the lower cast are moved to the scanner 62 from the cast holder and the cast and CT bite plate are positioned in the receiver 60 and scanned. The probe of the scanner 64 creates a data set of the surface of the CT bite plate on the lower cast.
The contours of the radiographic markers are scanned with the probe and the precise location of the markers recorded in three-dimensional computer space. A second scan is made of the lower cast with the CT bite plate removed from the cast, thereby providing an accurate digital data set for an image of the lower cast. Finally, the upper cast is placed in the receiver 60 and scanned. Since the orientation of the upper cast relative to the lower cast is known and reproduced with the cast holder 45 it is possible to move the data set for the upper cast in three-dimensional computer space to the exact relationship that existed when the casts were mounted in the cast holder.
In some examples, the upper and lower casts are placed within the scanner in a fully occluded position, not separated by the CT bite plate. In this position, the upper and lower casts are scanned together. The CT bite plate may then be inserted between the upper and lower casts, and then may be imaged to measure the separation generated by the CT bite plate.
Thus, the second scan will correspond in separation distance to the full CT image, including the CT bite plate. One example is a sphere 26 that is attached to the CT bite plate The probe from the contact digitizer records a data set for the exposed surface of the spherical radiographic marker and a specific point with an x, y, and z location can be recorded A useful example is the most superior point on the surface of the sphere.
The same point can be located on the data set from the CT scan of the patient. This data will be represented as grayscale bitmaps. The pixel that represents the most superior pixel on the radiographic image can also be easily located and recorded.
By locating three non-linear points on markers in the CT data as well as the contact digitizing data it is possible to move the data sets for the upper and lower cast into the same orientation as existed for the CT scan data. This creates a virtual model of the CT data as well as the contact digitizing data in the same three-dimensional computer space.
The CT data set is then reformatted as a 3D computer model such as a stereolithography. Three points 27 indicate the position of the markers in the scan data. The CT scan data 68 with points representing the radiographic markers 58 are illustrated with the radiographic scatter removed It is then possible to move the computer data representing the teeth 66 to its correct spatial position in relation to the CT data 68 using a three point move from the points recording the marker positions 27 to the computer position represented in the CT scan indicated by points Once moved, the radiographic and non-radiographic data can be joined using Boolean operations.
The same process can be used to move the scan data of the upper teeth into proper position the CT scan data. Referring to FIG. Points can be selected on or in the area around the articulating surfaces of the condyles 72 to represent the rotational center 74 for the mandible. In a conventional system for determining rotational center, the patient's ear holes are used with a face bow to determine an approximation of the position of the rotational centers. This improved method eliminates the need for a face bow, and the system can determine an approximation for the position of the rotational center.
Movement of the mandibular computer model can also be controlled by using standard condylar inclinations and Bennett angles to define average movements. This axis may be determined by selecting points on or in the area around the condyles 72 to represent the rotational center 74 for the mandible, as described above with reference to FIG. This may be done with a conventional input device, such as a keyboard, mouse, or other input device.
Because the CT data contains all the information for the mandible and condyles, selecting points on or in the area around the condyles 72 may identify the rotational center more accurately than prior art devices relying on the face bow. At a step , a user rotates the virtual model of the lower teeth and the mandible about the axis.
Using methods known the art, at a step , the user may then apply standard average measurements to computer model for lateral, protrusive and rotating movements to obtain calculated movement data. At a step , the obtained movement data is used to move the virtual model of lower jaw and teeth in relation to the upper jaw and head. In an alternative embodiment, instead of estimating and selecting the rotational axis, the rotational axis is determined through additional scanning steps.
One example of this process is shown in and described relative to FIG. This process may begin at a step , where a digital recording device, such as, for example ARCUSdigma, records the axis of opening, lateral, and protrusive movements of the mandible. At a step , at least one sensor is associated with the CT bite plate and calibrated to identify the position of the upper teeth relative to a head sensor.
This is represented and described with reference to FIG. At a step , the sensor attaches to the labial surface of lower teeth and calibrates with teeth in the CT bite plate to record the position of the lower teeth relative to the head sensor. At a step , the CT bite plate may be removed, and the patient opens and closes his mouth to record the kinematic location of axis.
At a step , the axis points are saved as digital data, such as for example, as ASCI Text, thereby recording the x, y and z position of the axis points. At a step , the patient moves the mandible laterally and protrusively, and the relative location, as determined by the sensors, is recorded.
At a step , the timing and location of movements are saved or stored as digital data, such as the ASCI Text. Then, as described above with reference to FIG. Positional tracking of the patient's physical mandible can be accomplished in many ways that include ultrasound, infrared, light and other methods of recording the positional relationship of the maxillae and mandible to a sensor. Four ultrasound microphones 76 are attached to the head and three ultrasonic transmitters 78 are attached to the CT bite plate with a magnetic fixation device The patient bites into the bite registration 28 to reproduce the same positional relationship existed when the CT scan was made.
This first calibration records the position of the ultrasonic transmitters 78 , CT bite plate 12 , and upper teeth in relation to the microphones The ultrasonic transmitters 78 are then attached to the lower bite fork and the software again is calibrated to record the positional relationship of the lower bite fork and transmitters to the microphones 76 with the patient's teeth in the CT bite plate.
The CT bite plate can then be removed to record the motion of the lower jaw to the upper. The patient's lower jaw is guided in opening and closing positions. The software can then calculate the actual position of the condylar rotational points 72 on the axis of rotation This information is recorded as digital data, such as ASCI Text, and can be directly related to the virtual jaw model described in this invention.
The patient can then move in protrusive and right and left lateral jaw movements. The software will record the timing and positional movement of the jaw and record the data as digital data, such as ASCI Text. This text can then be used to move the virtual model of the mandible in computer space.
Pixels with a grayscale value to render soft tissue FIG. Pixels with a grayscale value for bone and teeth can also be selected to render a computer model FIG. An exemplary system for performing the processes and methods described herein is shown in FIG. An output device, such as a display and input devices , such as keyboards, scanners, and others, are in communication with the processing unit Additional peripheral devices also may be present.
The processor may for example be a microprocessor of a known type. The memory may, in some embodiments, collectively represents two or more different types of memory.
For example, the memory may include a read only memory ROM that stores a program executed by the processor , as well as static data for the processor In addition, the memory may include some random access memory RAM that is used by the processor to store data that changes dynamically during program execution. The processor and the memory could optionally be implemented as respective portions of a known device that is commonly referred to as a microcontroller.
The memory may contain one or more executable programs to carry out the methods contained herein, including joining, separating, storing, and other actions including Boolean actions. The system also may include a CT machine , an imaging device , and a digital recorder These may be any of the CT machines, imaging devices, and digital recorders described herein.
Data from the CT machine , the imaging device , and the digital recorder may be accessed by the processing unit and used to carry out the processes and methods disclosed. Data may be communicated to the processing unit by any known method, including by direct communication, by storing and physically delivering, such as using a removable disc, removable drive, or other removable storage device, over e-mail, or using other known transfer systems over a network, such as a LAN or WAN, including over the internet or otherwise.
Any data received at the processing unit may be stored in the memory for processing and manipulation by the processor In some embodiments, the memory is a storage database separate from the processor Other systems also are contemplated.
The present invention relates to a dental tooth system that eliminates the steps of cutting, shaping and positioning pre-fabricated denture teeth by hand in the construction of dentures. Digital information from imaging casts of teeth and supporting tissues is joined in computer space to create a virtual model of the patient.
Virtual teeth that have the same shape as known pre-fabricated denture teeth are positioned in the computer model and then modified to have the proper form to be joined to the denture base material and to the opposing teeth.
The virtual model is used to position the actual pre-fabricated denture teeth in the proper spatial relationship to the dental cast and to cut the occlusal surface of the teeth and the retentive surface of the teeth that will be processed to the denture base material. This system eliminates much of the manual labor and cost of constructing dentures. Turning now the figures, FIG. The cast is positioned in a digital imaging system The imaging system 14 may be contact imaging system, or may be a light, laser, radiographic, holographic, or other suitable imaging system.
The imaging system creates a data set of the 3D surface of the dental cast in a known spatial relationship to the mounting plate receiver The data can be stored in computer memory as a text file recording specific x, y and, z points in relation to the mounting plate receiver or the points can be altered to produce a mathematical surface or solid model of the dental cast using mathematical algorithms known in the imaging art. In one exemplary embodiment, the surface image of the dental cast is saved as a.
The upper dental cast is imaged in the same manner to create a data set for the surface of the upper cast in relation to the mounting plate receiver. In some embodiments, the. Undercuts in the virtual model also maybe eliminated. Boolean operations may then be used to separate the dental cast data from the extruded object. The extruded object is saved as a separate. The record base can be manufactured with, for example, layered manufacturing such as stereolithography or any of a number of digital additive manufacturing systems that will make a plastic object from a.
In some embodiments, the record base can also be manufactured from a blank of plastic material using machining processes, such as, for example, a process performed with number controlled milling. For machining, such as when milling, the. The wax rim also may be designed as a digital 3D file of the planned shape needed for the dentist.
The wax rim, like the record base, may be manufactured using any suitable method, including using layered manufacturing and machining, including milling. Reference points on the virtual cast may be used to create the form of the wax rim. Some examples of references points are the retromolar pad and the labial sulcus. These reference points are well known in the dental art and are used by dental technicians to make wax rims using the traditional hand process. The form of the virtual wax rim is also saved as a.
Once the wax rim and record base have been manufactured they can be joined together and shipped to the dentist to try in the patient's mouth. An upper or lower cast can be used with this process.
While the example described above employs a digital process, in some exemplary embodiments, traditional processing can be used, including blocking-out undercuts with wax and making the record base with acrylic resin or a light cured composite. The wax rim can be formed by manually adding wax to the record base using anatomic landmarks.
The upper and lower wax rim and record base may then used by the dentist to evaluate the shape, aesthetics and bite relationship of the record base and wax rim in the patient's mouth. Any changes that are required may be made in the wax by the dentist. The dentist also may makes a centric bite record of the spatial relationship of the upper and lower jaws using the wax rims and record bases.
The centric bite record and record bases are then sent to be imaged again and to have pre-fabricated denture teeth positioned properly in the wax rim. Turning now to FIG. The lower cast is shown seated in the mounting plate receiver and the upper cast is held in position with a centric bite record , obtained from the dentist. The bite record was made by the dentist and it records the correct orientation of the upper cast to the lower for construction of the dentures.
A calibrating mounting plate receiver is attached to the upper mounting plate The calibrating mounting plate receiver may be used to record the spatial orientation of the upper mounting plate to the scanner and its mounting plate receiver This will position scan data about the upper cast and wax rims in the same orientation in the virtual model as exists in the patient's mouth.
Any additional scans of the upper cast, wax rim, or denture teeth can then be moved in the virtual model to the same orientation as existed with the bite record Next the upper and lower casts , and wax rims may be scanned to determine the shape of the rims after the dentist modified them with the patient. The reshaped wax rim may indicate information such as, for example, the midline, position of anterior teeth and the occlusal plane.
This information along with other virtual anatomic reference points may be used to position virtual denture teeth with a shape identical to the actual manufactured denture teeth in the computer model. This surface is generally not changed in the process of positioning denture teeth and making dentures because it has an ideal pre-formed aesthetic form. The occlusal biting surface of the denture tooth is oriented toward the opposing arch and in conventional methods is frequently ground by hand to create proper contact with the opposing denture teeth during function.
The surface directed toward the residual ridge is frequently ground extensively to accommodate the form of the residual ridge and implant components. As the surface is ground away, the retentive features in the denture tooth are also removed. Now referring to FIG.
This can cause the denture tooth to become less retentive in the denture base material unless the retentive features are reground into the tooth.
Space also may be created for implant components if the denture is stabilized with implants. Dentures are constructed from pre-fabricated denture teeth and each tooth has a specific form and color.
The form of the teeth is generally indicated by a mold number and each manufacturer maintains consistent manufacturing practices to insure that the teeth are always the same size and form. In some embodiments, the data set for each virtual tooth is made by scanning the actual pre-fabricated denture tooth and saving the scan data in a 3D file format. The scanning may be accomplished using any known scanning system, including those types identified herein. Alternatively, the data set may simply be provided by the tooth manufacturer or may otherwise be obtained.
There are many 3D file formats in the imaging art and the. The virtual teeth are moved in computer space to align with the virtual image of the wax rim , reference plane and record base, as shown in FIG. The virtual reference plane may be a flat virtual plane for monoplane tooth set-up or alternatively, a section of a sphere for setting the teeth to a curve.
Since the reference plane is virtual, any number of shapes can be used, providing the operator with multiple options. The disclosed methods are much improved over conventional methods since the virtual teeth can overlap other objects in computer space during the positioning process.
In conventional methods, the dental technician hand grinds each tooth and fits it to the residual ridge and opposing tooth before moving on to the next tooth. Using a virtual model, all the teeth can be positioned ideally as shown in FIG. Once the virtual teeth have been positioned in the correct relationship to the residual ridge and opposing teeth, a Boolean operation is used to cut the surface of the virtual teeth such that a space exists between the teeth and the residual ridge or implant components.
The cut surface of the denture teeth may be saved as a. The same process may be used to set and shape the lower virtual denture teeth. Several free. The positioning block 66 is made in a known x; y, and z orientation in computer space that reproduces the spatial orientation of the upper cast recorded with the centric bite record and calibrating mounting plate receiver A Boolean operation may then be used to cut the shape of the virtual denture teeth from the surface of the virtual positioning block This will leave indentations in the block that are the negative shape of the denture teeth.
The indentations are generally millimeters deep. The 3D data set of the virtual positioning block is then saved as a. The mill is used to cut the surface of the plaster to create indentations that are the negative shape of the actual denture teeth, as determined in the virtual model. Once the actual positioning block is prepared, the actual pre-manufactured denture teeth may be introduced into the indentations.
This is very simple task for a laboratory technician, since the correct position of each tooth has already been determined from the shape of the indentations in the plaster block. Next the surfaces of the denture teeth facing the residual ridge or implant components are cut by machining, such as with a mill The surface of the virtual teeth to be cut was discussed above, with reference to FIG.
After the surface of the denture teeth facing the residual ridge has been milled, the positioning block may be positioned in the same relation to the upper cast as was determined from the bite record FIG. The space discussed above during the virtual cutting discussion with reference to FIG.
This may embed and orient the teeth in the wax in the substantially identical position as the teeth in the virtual image. Once secured in the wax, the teeth may be lifted or otherwise removed from the positioning block In some exemplary embodiments, placement of the actual pre-manufacture denture teeth are placed within the indentations in the positioning block using an automated system, such as a robot system.
In some of these embodiments, the robot may select the teeth based on the virtual images, retrieve and orient them, and place them in the positioning block with the occlusal or biting surfaces embedded in the block, matching the virtual image.
In some embodiments, the actual denture teeth may be made or modified such that extensions or unique shapes are made that allow for precise positioning of the teeth in the positioning block using a robot system.
This can be accomplished using a robotic system to pick up each specific tooth and to position it in a specific position determined from the virtual positioning of the virtual denture teeth.
The process used on the upper denture teeth may be used to mill and position the lower denture teeth. Note that the upper and lower casts , , are in the same spatial orientation as existed when they were imaged with the centric bite record in FIG. Note also that the referencing points are also in the same orientation. The wax try-in set-up, with the teeth, is then sent to the dentist to try in the patient's mouth to validate the proper position of the teeth and to make static records of the patient's jaw movement.
Static records are a common method of approximating the positional orientation of the upper jaw in relation to the lower jaw. Normally one or more of protrusive, left, and right lateral static records are made. The protrusive record may be made with the patient's lower jaw moving forward until the upper and lower front teeth are in an end to end relationship.
A recording material such as wax is placed between the denture teeth to record the positional relationship of the upper denture to the lower. These static records allow duplication of the patient's jaw position and movements in the lab.
Now referring to the calibrating mounting plate receiver , note that the position of the three referencing points have changed to new positions with the static bite record in place, and each new point position can be recorded as an x, y, and z coordinate in relation to the lower mounting plate receiver After the position of the protrusive record has been made, the right lateral and left lateral records also may be placed between the teeth and the position of each reference point recorded again.
In some exemplary embodiments, a total of points are recorded, three for the centric position, three for the protrusive position and three for the right and the left lateral position. Since three points can determine the position of any object in computer space, the position of the virtual upper denture can be moved using each set of three points for the centric, protrusive, right lateral and left lateral position of the upper denture and teeth.
The position of the cusp in centric relation position and protrusive position is illustrated. The position of the upper cusp in a right lateral position is indicated by the reference numeral and the position of the upper cusp in a left lateral position is indicated by the reference numeral Note the area of interference that occurs when the molar is in the left lateral position.
This area of interference is also called a working interference in the dental art. Now referring to the right lateral position , note the area of interference , this area of interference is called a balancing interference. In a conventional process, these areas of interference were ground by hand to reduce the lateral forces on the denture and to maintain stability. The upper denture teeth have the same three dimensional form as the original design, as shown in FIG. The upper virtual model can be positioned in centric, right lateral, left lateral and protrusive positions and all positions in between.
The area marked protrusive is the area removed from the lower teeth from centric relation position to the protrusive position to reduce or eliminate interference. The area marked lateral area is the area removed from the centric to the right and left lateral position to reduce or eliminate interference.
Boolean operations are used to remove material from the lower virtual denture teeth. Illustrated in the preferred embodiment is a balanced type of occlusion but any type of denture tooth or concept of denture occlusion can be created with this virtual design process. Static centric, right lateral, left lateral and protrusive records are described in the disclosed embodiments of this disclosure, but other methods of tracking of the mandible can be used also and they include, for example: ultrasound, infrared, light, averaged measurements to record the positional relationship of the maxillae to the mandible, and other suitable methods.
This recorder employs four ultrasound microphones attached to the head and three ultrasonic transmitters attached to the lower record base. The positional movement and timing of the movement of the jaw is saved as z, y, and z coordinates in ASCI text and can be used to create movement of the virtual computer model, enabling interference recognition and bilateral balancing of the upper and lower dentures.
Processing includes removing the wax and record base from the teeth and fixing them in a suitable denture base material to secure them in place relative to each other. This may be done using, for example, a heat or autopolymerizing denture base material.
As explained above, the pre-manufactured denture teeth have been cured in the denture base material, and now they may be returned to the mounting plate. Any errors introduced during the processing are corrected by machining, such as by milling, the surfaces of the denture teeth to the shape of the virtual denture. Since the exact orientation of the upper cast is known in relation to the mounting plate and the mill, it is a simple process to attach the processed denture and cast to the mill and cut the biting surfaces to insure they are the same shape as originally designed.
This ensures a better fit than traditional methods, where processing errors were not easily detected or repaired. In addition, the lower teeth are cut with the mill to have a surface that is in harmony with upper teeth as they move against the lower tooth surfaces. This harmony is accomplished by recording the virtual movements of the upper teeth in centric, lateral and protrusive position and to use Boolean computer operations remove virtual material from the surface of the lower denture teeth and create surfaces that are in harmony with the patient's jaw movement, as discussed above with reference to FIG.
The surface of the teeth is saved as a. This is a simple process using Boolean operations and recording multiple upper jaw positions in relation to the lower. In addition, the memory also may include stored image data of a plurality of pre-manufactured teeth that is retrievable using the processor to select one or images.
In some exemplary embodiments, the images may be stored on a database accessible only over a network connection, such as a WAN or LAN including the Internet, among other networks. Further, the processing unit may be configured to generate programming code for operating a tool cutting machine, such as an NC mill, as described below. The system also may include a machining tool, such as an NC mill , an imaging device , and a digital recorder The NC mill may be any other machining suitable for machining the pre-fabricated teeth, positioning blocks, record bases, wax rims, or other components as described herein.
Data from the NC mill , the imaging device , and the digital recorder may be accessed by the processing unit and used to carry out the processes and methods disclosed. Data may be communicated to or from the processing unit to the NC mill , the imaging device , and the digital recorder by any known method, including by direct communication, by storing and physically delivering, such as using a removable disc, removable drive, or other removable storage device, over e-mail, or using other known transfer systems over a network, such as a LAN or WAN, including over the Internet or otherwise.
Frequently patients have teeth that must be removed due to dental decay or periodontal disease. New advances in dental implant treatment make it possible to create artificial teeth attached or supported by dental implants.
Immediate dentures are made for these patients and the immediate dentures are made before the natural teeth are removed. The device is programmed via software with a regular PC with the device attached via a cable and settings are stored on the BTE microphone unit.. The FDA k clearance for Conductive hearing loss is the second for the SoundBite prosthetic device and marks another significant milestone for the company. The SoundBite hearing system will be available starting early this fall through physicians and audiologists in a few select markets in the US see where at www.
Thanks for sharing this info! This is great info and I have been looking for a long time for something like this. Thanks again:. Interesting article