JP4295076B2 - Dental prosthesis manufacturing model - Google Patents

Description

  The present invention relates to the manufacture of a dental prosthesis, and more particularly to a method for manufacturing a dental prosthesis suitable for manufacturing using CAD / CAM.

The dental prosthesis is intended to replenish the tooth formation site and return to the tooth close to the natural tooth, and is intended to restore the tooth state that matches the formation site and does not change from before the formation. In the present situation, the manufacturing requires many steps.
Attempts have been made to incorporate measurement and manufacturing using a computer such as CAD / CAM into this process for the sake of simplicity.

In this method, the tooth formation site or the surface shape of the model where the formation site is restored is converted into coordinate data using techniques such as contact probe, non-contact laser and optical imaging, and this coordinate data is modified and modified. After that, the prosthesis block is processed by an NC machine tool, which makes it possible to manufacture a low-cost prosthesis without human labor, but there is no change in the process until the first model is created. In order to perform contact measurement using a probe and non-contact measurement using a laser beam, etc., it is impossible in a close dentition environment. Due to the complexity, the significance of CAD / CAM is diluted.
In addition, when a margin line is obtained from a model, it is impossible to obtain a margin line with high accuracy because it is lost in the manufacturing process when a complicated model is manufactured.

In Japanese Patent Laid-Open No. 04-253853, as a model for creating a prosthesis by CAD / CAM, an impression material is arranged between an abutment tooth and an occlusal tooth after the abutment tooth is formed, The impression material including the occlusal tooth surface and the surface state of the abutment tooth is obtained by clamping with teeth, and a model is formed from the shape copied on the impression material, and the model surface is contacted with a CAD / CAM contact probe. After measuring the surface shape by the method, it is described that a prosthesis shape is obtained.
Japanese Patent Laid-Open No. 04-253853 discloses that the surface and height of the occlusal teeth and the maximum ridge are accurately obtained, but there is no disclosure about accurate measurement of the margin line.
JP 04-253853 A

As described above, the margin line (boundary portion between the prosthesis and the natural tooth when the prosthesis is mounted) can be detected when the abutment tooth shape is molded with the impression material, and the timing thereof is determined. If you miss it, you need to take another impression, which increases the burden on patients and doctors.
The margin line indicates the boundary between the natural tooth and the prosthesis after the prosthesis is inserted and arranged in the formation site. If there is a gap in this boundary, secondary caries will occur. It is necessary to have a matched connection.

  In view of the above, the present invention provides an impression acquisition step of obtaining a tooth shape of a tooth forming part and its adjacent region, a step of extracting a characteristic part such as a margin line from the shape of the tooth forming part, and the acquired impression By injecting the curable member from the adjacent region to the feature site shape, it is possible to form a mold having a state suitable for mechanical and optical measurement of the margin line. Further, not only CAD / CAM but also normal general technical work, it is possible to easily extract the shape of a characteristic part such as a margin line.

The present invention enables accurate detection of margin line information, which is a parameter indispensable when processing a prosthesis, by CAD / CAM with a simple operation at the time of impression acquisition. In addition to the prosthesis processing by CAD / CAM, it is possible to accurately detect margin line information even with ordinary general technical work, with simple work. The present invention significantly deviates from the conventional model manufacturing process. It can be carried out in a range of work that can be done, and it can be created enough with the work so far without giving special training to dentists and dental technicians, giving a sense of security.

The prosthesis in the present invention is an inlay, a crown bridge, or the like. A crown that is prosthetic on the abutment tooth after mainly forming the abutment tooth is preferable. In addition to the crown, it is also effective for inlay bridges and other prostheses.
Tooth formation site and its adjacent region in the present invention indicate the teeth on both sides of the tooth to be prosthetic, and if two prosthetic teeth are adjacent to each other, indicate both sides, but if there is a tooth only on one side, Only one side may be sufficient.
In addition, at least the adjacent region may be used, and the adjacent tooth may not be included. That is, according to the present invention, it is only necessary to obtain the first mold by filling the curing agent with the margin line as a boundary when acquiring an impression. Examples of the curing agent include an immediate polymerization resin and a pattern resin, but are not limited thereto.
It is preferable to perform the exclusion operation to obtain the unevenness that makes the margin line stand out on the impression, but if the margin line can be found on the impression without performing the exclusion operation, the work to make the unevenness of that portion stand out May be performed.

After forming the first mold, a curing agent is filled from above to form a second mold.
Examples of the curing agent for the second mold include, but are not limited to, gypsum and quick-hard cemented gypsum.
After these molds are cured, a mold is formed in which the first mold is bonded onto the second mold.
By scanning and measuring the first mold with a contact or non-contact probe or the like and converting it into three-dimensional data, the diameter (interdental distance), height, and further buccal tongue distance of the maximum ridge is obtained. An accurate margin line and an abutment tooth surface shape can be obtained from the second mold.
In addition, information such as the diameter (interdental distance), height, and buccal distance of the maximum ridge can be obtained from a bite WAX or the like obtained in advance.
From the first mold, an accurate margin line is scanned and measured with a contact or non-contact probe, etc., and converted into three-dimensional data. There are cases where the diameter (interdental distance) and the height of the are required.
The mold can also be used to check if the desired prosthesis has been formed or to compensate after the prosthesis has been manufactured.
In some cases, a crown mold may be formed on the mold by waxing up, and the surface shape of the mold may be measured by CAD / CAM to form three-dimensional data.
Further, the mold can be applied not only to the three-dimensional data conversion by CAD / CAM but also to normal general technical work.

In the present invention, at the time of impression acquisition, a convex portion showing at least a margin line is formed in the impression.
Since the work is performed in a state where there is a patient, confirmation is easy.
The convex portion showing the margin line is not limited to the convex portion and may be a concave portion as long as the curing agent at the time of obtaining the first mold is retained. In addition, irregularities may be formed by performing a modification work on some landmarks.

Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1A shows a state after the abutment teeth 13 are formed, and adjacent teeth are indicated by 11 and 12.
A state in which a pressure removal operation for raising the margin line 15 in advance is performed. The exclusion operation is an operation for spreading and temporarily fixing the gingiva with respect to the state where the margin line 15 of the abutment tooth 13 is hidden by the gingiva 14, and wrapping the exclusion yarn around the periphery of the gingiva, The gingiva of the part wrapped around is temporarily fixed in a state of being spread. Since the purpose of the exclusion operation is to spread the gingiva, it may be a material / medicine other than the exclusion thread, and can be impregnated with or attached to the drug solution for exclusion and can be inserted between the gingiva and the tooth. May be used. The exclusion part is indicated by AP.

Next, the impression material 16 filled in the tray 10 is pressed against the periphery of the abutment teeth 13 and the adjacent teeth 11 and 12 to take an impression. FIG. 1B shows after the impression is taken. The margin line portion 20 around the abutment tooth recess 18 has an impression in the state of protruding as an exclusion portion APA, and 17 and 19 are adjacent tooth recesses corresponding to the adjacent teeth 11 and 13 shown in FIG. Is formed. Reference numeral 18 denotes an abutment tooth recess corresponding to the surface shape of the abutment tooth 13 of FIG.
In the impression material 16 of the tray 10, the quick-drying polymer resin material 21 is filled in the recesses 17 and 19 formed by the adjacent teeth with the margin line portion 20 emphasized by the exclusion portion APA as a boundary, and the first mold 21 is filled. Form. In some cases, it is better to fill the portion with the margin line portion 20 emphasized by the exclusion portion APA as a boundary with paraffin WAX or the like.
Further, a curing agent is filled in the entire area of the impression material 16 (FIG. 1C).

After the curing, as shown in FIG. 2A, the first mold 21 forms the adjacent tooth mold, and the second mold 22 is formed around the abutment tooth portion 26. The exclusion portion is a portion for specializing the margin line, and may be cut out as necessary.
The first mold 21 and the second mold 22 are detachable, and the combined state is as shown in FIG.
The mold measures the surface shape using a contact-type or non-contact-type measurement probe or an optical imaging method. At that time, in order to measure the surface shape of the abutment tooth and the margin line, the separator 29 may be cut from the second die.

The measurement is performed by measuring the margin line 30 of the second mold or measuring the margin line portion 23 of the first mold 21. However, it is more preferable to measure the margin line 23 of the first mold 21. In some cases, 29 may not be manufactured.
Furthermore, from the first mold, the length 27 and the cheek tongue length of the maximum ridge are measured, and the tooth height value 28 can be measured. Further, the tooth height value 28 can be measured by installing a bite WAX obtained in advance on the first mold 21.
The first mold 21 and the second mold 22 may be measured while being combined or may be measured in a separated state, but when measuring separately, set common position information in advance. This makes it easy to combine the first type data and the second type data on the three-dimensional data.

After measuring the three-dimensional data of the margin line 30 and the diameter 27 and the tooth height value 28 corresponding to the maximum bulge portion into data, the virtual prosthesis is converted into three-dimensional data and evaluated. The prosthesis is formed by grinding, cutting, other rapid prototype processing using photo-curing by laser irradiation, and other processing.
For the processing, the data is transmitted to a center having technical ability through the Internet or the like to be processed, and is input to an NC processing apparatus possessed by itself and processed by a known method.
After processing, this prosthesis can be applied to the first mold and the second mold, and the finish can be confirmed.

  According to the present invention, a more accurate prosthesis can be manufactured, and conventionally, a trimming operation as a pretreatment is not always required, and a technician and a dentist can easily manufacture a prosthesis.

It is a figure for demonstrating the Example of this invention. It is a figure for demonstrating the Example of this invention.

Explanation of symbols

10 Tray 11, 12 Adjacent tooth 13 Abutment tooth 14 Gingival 15 Margin line 16 Impression material 17, 19 Adjacent tooth recessed part 18 Abutment tooth recessed part 20, 30 Margin line part 21 First mold 22 Second mold

Claims (3)

Measure the surface shape of the model obtained by filling the mold that has the shape of the area including part or all of the abutment teeth and adjacent teeth as a recess and then curing, using a measurement probe or optical imaging Then, in the dental prosthesis manufacturing model for producing the prosthesis by producing three-dimensional data of the shape of the dental prosthesis from these measured values and processing the raw blocks based on the three-dimensional data. ,
The model is hardened by injecting a hardener around the concave / convex part consisting of a margin line in a concave model obtained from a part or all of the adjacent tooth centered on the abutment tooth. The first model from which the information on the maximum ridges, the distance between adjacent teeth, the height, and the shape data of the surroundings is obtained, and the concave portion corresponding to the abutment tooth and the hardener on the first model. The abutment tooth shape formed by injecting and hardening and the second model capable of measuring the margin line are formed, and the first model and the second model can be combined and separated. Dental prosthesis manufacturing model. The dental prosthesis manufacturing model according to claim 1, wherein materials of the first model and the second model are different . The dental prosthesis manufacturing model according to claim 1, wherein the concavo-convex portion is formed so as to emphasize an exclusion treatment site on an impression .

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