KR20220155928A - Method of manufacturing removable denture metal frame - Google Patents

Abstract

A method for manufacturing a removable denture metal frame according to various embodiments of the present invention includes the following steps: outputting a resin frame by 3D printing; curing the resin frame; burying the resin frame cured in the curing step; recalling the investment ring buried in the investment step; casting by melting an alloy in the summoned investment ring in the summoning step; polishing the metal frame cast in the casting step; and fitting the metal frame polished in the polishing step to a model.

Description

Method of manufacturing removable denture metal frame {Method of manufacturing removable denture metal frame}

The present invention relates to a method for manufacturing a removable denture metal frame. Specifically, the present invention relates to a method capable of manufacturing a highly accurate removable denture metal frame.

With the development of science and medical technology, average life expectancy has increased worldwide, and the domestic aging index is 104.8% as of 2017, with the population aged 85 or older already exceeding the population aged 15 or older, and the proportion of the population aged 65 or older as of 2020 is about 20%. has entered a 'super-aging society' in which one in five people becomes an elderly person.

In addition, since November 2017, the demand for removable dentures (dentures, partial dentures) is rapidly increasing due to the reduction in the cost of insurance dentures. unable to meet the growing demand.

Recently, we are trying to solve this problem by introducing additive manufacturing method among CAD/CAM systems. Among the additive manufacturing methods, the types of 3D printing that are widely used in dentistry include FDM/SLA/DLP.

However, the removable denture resin frame output by the 3D printing method must be finally made into a metal frame through burial, summoning, and casting. etc. will affect the performance of the final metal frame.

For example, in the case of burial conditions, there is a problem that if the mixing ratio is not properly controlled, the expansion rate control fails and the accuracy of the final metal frame is lowered. In addition, in the process of summoning the investment material ring, there is also a problem such as not being able to withstand the summoning temperature, and the investment material ring is broken, leading to casting failure.

In addition, in the case of summoning conditions, if sufficient summoning temperature and mooring time are not applied, there is a problem in that the buried resin frame is not completely summoned and residues remain, which deteriorates the accuracy of the final metal frame in the casting process.

The present invention is to solve the above problems, it is possible to provide a method for manufacturing a removable denture metal frame with high accuracy.

A manufacturing method of a removable denture metal frame according to various embodiments of the present invention includes the steps of outputting a resin frame by 3D printing; curing the resin frame; burying the resin frame cured in the curing step; Recalling the investment ring buried in the investment step; Casting by melting an alloy in the summoned investment ring in the summoning step; polishing the metal frame cast in the casting step; and fitting the metal frame polished in the polishing step to the model.

The present invention is a method for manufacturing a removable denture metal frame with high accuracy, and can increase the degree of matching between the removable denture metal frame and the CAD design file. In addition, performance indicators related to 2-dimensional fit, 3-dimensional fit, output processing stability, Vickers hardness, and Precision of the removable denture metal frame manufactured by the method of the present invention can be improved.

1 is a process flow diagram of a method for manufacturing a removable denture metal frame according to an embodiment of the present invention.
Figure 2 shows the trueness evaluation process of the removable denture metal frame.
Figure 3 shows a two-dimensional fit evaluation method of the removable denture frame using the Silicone replica technique.
4 shows a cross-sectional view of the measurement position during the two-dimensional fit evaluation, and I shows three points measured with a digital microscope.
5 shows Geomagic Verify software for 3D fitness measurement.
6 illustrates a process of measuring the three-dimensional fit of the palate and the retaining portion of the metal frame.
7 shows a process of evaluating the precision of a metal frame.
8 shows a cube of 10 × 10 × 10 mm for evaluation of processing stability of the output product.
9 is a photograph of measuring stability of output processing using a digital caliper.
10 shows a schematic diagram of Vickers hardness measurement and a method for calculating indentations.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is one well known and commonly used in the art.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

A manufacturing method of a removable denture metal frame according to various embodiments of the present invention includes the steps of outputting a resin frame by 3D printing; curing the resin frame; burying the resin frame cured in the curing step; Recalling the investment ring buried in the investment step; Casting by melting an alloy in the summoned investment ring in the summoning step; polishing the metal frame cast in the casting step; and fitting the metal frame polished in the polishing step to the model.

First, in the step of outputting the resin frame by 3D printing, additive manufacturing may be used among CAD/CAM systems. More specifically, a model can be scanned to form an STL file before 3D printing, and a design for manufacturing a removable denture frame can be performed through CAD design. Next, a slicing process can be performed to output the CAD design file. This slicing CAD design file can be output by 3D printing.

Specifically, 3D printing may be performed in a stereo lithography apparatus (SLA) method. Also, 3D printing may be performed with a stacking angle of 30 degrees to 60 degrees and a layer thickness of 80 μm to 120 μm. Preferably, 3D printing may proceed with a stacking angle of 45 degrees and a layer thickness setting of 100 μm. Under these conditions, an optimal removable denture resin frame can be output.

Next, the output resin frame can be made into a metal frame through hardening, burial, summoning, and casting.

Specifically, in the curing step, the output resin frame may be post-cured. For example, in the curing step, post-curing may be performed for 10 to 20 minutes.

Preferably, post-curing may be performed for 15 minutes. This curing time improves the match between the removable denture metal frame and the CAD design file. In addition, performance indicators related to 2-dimensional fit, 3-dimensional fit, print processing stability, Vickers hardness, and precision can be improved.

Next, in the burial step, the cured resin frame may be buried. In the step of burying, the resin frame may be buried by mixing investment material powder and liquid. The investment material powder may be a variety of phosphate-based investment materials. For example, the investment material powder may have a composition including quartz, cristobalite, magnesium oxide, and ammonium phosphate. The liquid may have a composition including amorphous silica, an alkali such as Na ² O, and water.

At this time, the mixing ratio (burial material powder: liquid) may be 24 ml to 28 ml. That is, the resin frame may be buried by mixing 24 ml to 28 ml of liquid per 100 g of investment material powder. Preferably, the resin frame may be buried by mixing 26 ml of liquid per 100 g of investment material powder. The expansion rate can be adjusted through the investment material mixing ratio, which can help in the production of a more accurate final metal frame because it is possible to compensate for the shrinkage of the casting alloy during casting. In addition, the matching degree of the removable denture metal frame and the CAD design file can be increased through this mixing ratio. In addition, performance indicators related to 2-dimensional fit, 3-dimensional fit, print processing stability, Vickers hardness, and precision can be improved.

Next, in the summoning step, the investment material ring buried in the investment step may be summoned. At this time, the summoning temperature and holding time of the buried resin frame are important because they can be directly related to the accuracy, strength, and lifespan of the final metal frame.

Specifically, in the summoning step, the buried investment material ring may be summoned at a summoning temperature of 850 ° C to 950 ° C. Preferably, the summoning step may be performed at a summoning temperature of 900 °C.

Meanwhile, in the summoning step, the mooring time may be 30 to 90 minutes. Preferably, it can proceed for 90 minutes of mooring time in the summoning step.

The degree of conformity between the metal frame of the removable denture and the CAD design file can be increased through the specific heat retention temperature and holding time. In addition, performance indicators related to 2-dimensional fit, 3-dimensional fit, print processing stability, Vickers hardness, and precision can be improved.

Next, in the casting step, the alloy may be melted and cast in the summoned investment ring in the summoning step. For example, it can be cast by melting a non-precious metal alloy into a summoned investment ring. Specifically, the non-noble metal alloy may be an alloy including any one selected from the group consisting of Co, Cr, Mo, Mn, Si, Nb, Ta, and C.

Next, in the polishing step, the cast metal frame may be polished.

In the next fitting step, the polished metal frame can be fitted to the model. For example, a polished metal frame may be used by mounting it in the oral cavity.

Hereinafter, it will be described in detail through specific embodiments of the present invention.

However, the following examples are only for exemplifying the present invention, and the present invention is not limited by the following examples.

Example 1: Trueness evaluation of removable denture metal frame according to post-curing time

It was produced in the process sequence according to FIG. 1, but the trueness of the metal frame produced by varying the post-curing time before burial after 3D printing was evaluated. Referring to FIG. 2 , trueness evaluation means the degree of agreement between an expected value of a measurement result and a true value. That is, the more the fabricated removable denture metal frame matches the CAD design file, the fewer errors and the higher the accuracy.

As a result of the evaluation of trueness, referring to Table 1 below, the average value of the post-curing time group of 15 minutes was 88.0 μm, and the average value of the post-curing time group of 30 minutes was 98.8 μm. That is, it was determined that it was most appropriate to cure and bury the resin frame after 15 minutes.

Unit: RMS (μm) Trueness Post cure time 15 minutes One 95.9 2 75.7 3 85.5 4 82.5 5 100.6 Mean±SD 88.0±10.1 Post cure time 30 minutes One 109.9 2 87.1 3 89.5 4 98.8 5 108.9 Mean±SD 98.8±10.6

Example 2 : Production of the final metal frame according to the conditions of the mixing ratio and selection of the optimal mixing ratio

The resin frame was buried by mixing 24ml, 26ml, and 28ml of liquid per 100g of investment material powder, and the final metal frame was produced through the summoning and casting process. After removing and trimming the sprue of the cast metal frames, the trueness evaluation was conducted. As a result of the evaluation of trueness, referring to Table 2 below, the average value of the lethargy ratio 24ml group was 190.3㎛, the average value of the lethargy ratio 26ml group was 129.7㎛, and the average value of the lethargy ratio 28ml group was 169㎛. That is, the average value of the 26ml mixing ratio group was 129.7 μm, which was the best, and it was determined that it was most appropriate to bury the resin frame with the mixing ratio 26ml.

Unit: RMS (μm) Trueness Honsubi 24ml One 134.3 2 134.6 3 136.7 4 173.4 5 372.6 Mean±SD 190.3±103.2 Honsubi 26ml One 114.4 2 150.9 3 149.7 4 112.3 5 121.4 Mean±SD 129.7±19.1 Honsubi 28ml One 313.8 2 181 3 121.8 4 105.2 5 123.4 Mean±SD 169.0±85.9

Example 3: Trueness evaluation of removable denture metal frame according to summoning temperature

The trueness of the metal frame produced according to the summoning temperature was evaluated. That is, the buried investment material ring was summoned according to the summoning temperature of 850 ° C, 900 ° C, and 950 ° C, and the final metal frame was produced through a casting process. After removing and trimming the sprue of the cast metal frames, the trueness evaluation was conducted. As a result of the trueness evaluation, referring to Table 3 below, the average value of the summoning temperature 850 ° C group was 124.7 μm, the average value of the summoning temperature 900 ° C group was 114.6 μm, and the average value of the summoning temperature 950 ° C group was 139.5 μm. That is, it was determined that it was most appropriate to summon the resin frame at a summoning temperature of 900°C.

Unit: RMS (μm) Trueness Summoning temperature 850℃ One 132.7 2 117.9 3 120.9 4 121 5 131.2 Mean±SD 124.7±6.7 Summoning temperature 900℃ One 122.5 2 145 3 100.6 4 111.1 5 93.8 Mean±SD 114.6±20.2 Summoning temperature 950℃ One 142.8 2 119.4 3 153.3 4 129.2 5 152.6 Mean±SD 139.5±14.9

Example 4: Trueness evaluation of removable denture metal frame according to mooring time

The trueness evaluation of the fabricated metal frame was conducted according to the mooring time. After summoning by mooring for 30 minutes, 60 minutes, and 90 minutes at a summoning temperature of 300 ℃ and 900 ℃, the final metal frame was produced through a casting process. After removing and trimming the sprue of the cast metal frames, the trueness evaluation was conducted. As a result of the evaluation of trueness, referring to Table 4 below, the average value of the 30-minute holding time group was 113.3 μm, the average value of the 60-minute holding time group was 106.3 μm, and the average value of the 90-minute holding time group was 98.8 μm. In other words, it was determined that it was most appropriate to moor 90 minutes when summoning the resin frame.

Unit: RMS (μm) Trueness Mooring time 30 minutes One 122.5 2 129.8 3 110 4 113 5 91 Mean±SD 113.3±14.7 Mooring time 60 minutes One 116 2 106.5 3 99.1 4 102 5 108 Mean±SD 106.3±6.5 Mooring time 90 minutes One 109.9 2 87.1 3 89.5 4 98.8 5 108.9 Mean±SD 98.8±10.6

Example 5 : Evaluation of major performance indicators of removable denture metal frames manufactured according to the optimal process technology

The main performance indicators of the metal frame manufactured according to the process conditions optimized in Examples 1 to 4 (post-curing time 15 minutes + mixing ratio 26 ml + summoning temperature 900 ° C + holding time 90 minutes) were evaluated. That is, 2-dimensional fit, 3-dimensional fit, print processing stability, Vickers hardness, trueness, and precision were evaluated.

(1) 2-dimensional fit evaluation

In the two-dimensional fit evaluation, the adaption between the model and the metal frame was measured using the silicone replica technique as shown in FIG. 3 .

In the silicone replica technique, the thickness of light body silicone represents the gap between the model and the metal frame, and the smaller the thickness of light body silicone, the better the fit and retention.

The cross section of the cut light body silicone was measured with a digital microscope, and the measured position is the median point of the palate and the median point between the top of the left and right ridges and the midline (Left point, Right point) was.

As a result of evaluating the two-dimensional fit of the removable denture metal frame manufactured according to the optimal process technology, referring to Table 5 below, it was confirmed that the average value was 104 μm, which was very excellent.

Unit : ㎛ Left(L) Middle(M) Right(R) Mean 2-dimensional goodness of fit One 76.36 102.32 126.30 101.66 2 93.74 64.04 121.11 92.96 3 181.27 117.68 126.15 141.70 4 83.15 75.00 95.58 84.58 5 121.18 90.50 91.30 100.99 Avg. - - - 104.38 StDev - - - 21.99

(2) 3-dimensional fit evaluation

The 3D fit evaluation was measured by scanning the oral model and the inner surface of the resin frame of the removable denture fabricated by 3D printing, and then overlapping them through Geomagic Verify software as shown in FIG. 5 . Referring to FIG. 6, in order to evaluate the correct fit value of the removable denture metal frame, the three-dimensional fit was evaluated by dividing the retaining part and the palate.

As a result, referring to Table 6 below, as a result of evaluating the three-dimensional fit of the removable denture metal frame manufactured according to the optimal process technology, the average value of the fit of the retainer was 80.9㎛, and the average value of the fit of the palate was 58.4㎛, which is an excellent performance indicator. .

Unit: RMS (μm) Adaptation maintenance department One 65.1 2 86.1 3 87.4 4 66.1 5 99.9 Mean±SD 80.9±15.0 palate One 53.1 2 58.7 3 65.2 4 65.5 5 49.4 Mean±SD 58.4±7.2

(3) Trueness evaluation

As a result of evaluating the trueness of the removable denture metal frame manufactured according to the optimal process technology, referring to Table 7 below, the average value was 88.0 μm, which showed excellent performance indicators.

Unit: RMS (μm) Trueness One 95.9 2 75.7 3 85.5 4 82.5 5 100.6 Mean±SD 88.0±10.1

(4) Precision evaluation

Precision evaluation means the degree of agreement between measurement results, and was measured as shown in FIG. 7 . That is, Precision means the degree of matching between the manufactured removable denture metal frames, and the more the metal frames match each other, the higher the precision.

As a result of precision evaluation of the removable denture metal frame manufactured according to the optimal process technology, the average value was 55.1㎛, which satisfied the excellent performance index.

Unit: RMS (μm) Precision One 75.9 2 64.9 3 51.1 4 48.1 5 34.6 6 76.8 7 52 8 64.4 9 38.1 10 45 Mean±SD 55.1±14.8

(5) Evaluation of output processing stability

To evaluate the processing stability of the printed product, as shown in FIG. 8, the processing error was evaluated by measuring the width × length × height (10 × 10 × 10 mm) of the repeatedly manufactured workpiece.

Referring to FIG. 9 , the width, length, and height of the processed cube were indicated in red (width), blue (length), and black (height), respectively, and were measured using digital calipers. The machining error of the width × length × height of the processed cube must exist within the range of 9.9 to 10.1 mm.

As a result of evaluating the processing stability of the cube workpieces manufactured according to the optimal process technology, referring to Table 9 below, the average value of the horizontal area was 9.97mm, the average value of the vertical area was 9.97mm, and the average value of the height area was 9.95mm, which is an excellent performance indicator. confirmed.

Unit: mm width Vertical Height One 9.98 9.97 9.97 2 10.03 9.91 9.92 3 9.96 10.03 9.95 4 9.96 9.94 9.97 5 9.93 10.00 9.96 Mean±SD 9.97±0.04 9.97±0.05 9.95±0.02

(6) Vickers hardness evaluation

Referring to FIG. 10, the Vickers hardness evaluation is a method of measuring the hardness by the surface of the mark made on the specimen after applying a static load to the specimen with a diamond presser having a facing angle of 136 ° using a microhardness machine. When evaluating the Vickers hardness, it was measured using a specimen of width × length × height (10 × 10 × 2 mm). After placing the fabricated metal specimen in the Vickers hardness measuring instrument, a total of 5 static loads (0.2 gf) are applied for 15 seconds, and the average of the two facing angles is obtained. The Vickers hardness measurement formula is Hv = 0.1891 × F / d ² , where d is the average of two face-to-face angles and F is the static load of a diamond indenter with a face-to-face angle of 136°.

As a result of Vickers hardness evaluation of specimens manufactured according to the optimal process technology, referring to Table 10 below, the average value was 420 HV0.2, which satisfied excellent performance indicators.

Unit: HV0.2 1 measurement 2 measurements 3 measurements 4 measurements 5 measurements Mean One 412 399 404 422 411 410 2 409 409 404 441 407 414 3 432 441 430 427 422 430 4 411 404 422 441 422 420 5 446 427 411 435 409 426 Avg. - - - - - 420 StDev - - - - - 8

The above description of the present invention is for illustrative purposes, and those skilled in the art can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. There will be. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present invention. do.

Claims (7)

Outputting a resin frame by 3D printing;
curing the resin frame;
burying the resin frame cured in the curing step;
Recalling the investment ring buried in the investment step;
Casting by melting the alloy in the summoned investment ring in the summoning step;
polishing the metal frame cast in the casting step; and
Method of manufacturing a removable denture metal frame comprising the step of fitting the metal frame polished in the polishing step to the model. According to claim 1,
The 3D printing method of manufacturing a removable denture metal frame, characterized in that in progress in the SLA (Stereo Lithography Apparatus) method. According to claim 1,
The 3D printing method of manufacturing a removable denture metal frame, characterized in that proceeding at a layer thickness of 30 to 60 degrees and a layer thickness of 80 to 120 ㎛. According to claim 1,
In the curing step, the method of manufacturing a removable denture metal frame, characterized in that to proceed with post-curing for 10 to 20 minutes. According to claim 1,
In the step of burying, the manufacturing method of the removable denture metal frame, characterized in that the resin frame is buried by mixing with 24 ml to 28 ml of liquid per 100 g of investment material powder. According to claim 1,
In the summoning step, the manufacturing method of the removable denture metal frame, characterized in that the summoning of the buried investment ring at a summoning temperature of 850 ℃ to 950 ℃. According to claim 1,
In the summoning step, the method of manufacturing a removable denture metal frame, characterized in that in progress for a mooring time of 30 minutes to 90 minutes.

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