★ How Dental PFM Crowns are Made | Step-by-Step Photos ☠- wet tissue paper manufacturing proce

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★ How Dental PFM Crowns are Made | Step-by-Step Photos ☠- wet tissue paper manufacturing process

by:NOX BELLCOW     2019-11-12
★ How Dental PFM Crowns are Made | Step-by-Step Photos ☠ -  wet tissue paper manufacturing process
Before I learned myself how to make dentures, crowns, and orthodontic appliances, I didn't even consider that these things were customized individually by the actual person --
When the dentist impressed me with my teeth, I never thought about it.
But it's a job, and not many people will hear about it, let alone know more about it --
I mean I just accidentally found out about it!
But now I'm
A sophisticated manual experience of time
The consumption process that is making the Crown, I would like to share how difficult it really is, not recognized and undervalued.
If you have to have a crown, think about someone somewhere and tailor it specifically for you :-
I hope you find this insight interesting.
These are impressions of the upper and lower teeth delivered to the laboratory.
From clean to disgusting, these are OK!
They must be disinfected first.
The impression on the right has a part of the impression material of different colors, which the Crown is destined to use.
This golden material is smoother than the blue one, so it's also better to capture the details.
That's why it's used in the area where the crown is installed --
It really needs to be accurate.
Porcelain crown is porcelain-fused-to-
The metal crown, consisting of a cap-shaped metal substructure with a porcelain coating (making it perfectly suited to the patient's teeth.
Patients who need a porcelain crown need the dentist to grind the damaged teeth to remove the damaged tissue and create enough space to hold the metal and porcelain crown.
The above impression belongs to a patient who did not leave enough undamaged tooth tissue to support the crown, so the whole tooth was removed and a cone Ridge was drilled on their gums.
A metal pile will be made to install the hole, which will support the porcelain crown like a tooth.
You may see the Jinsui in the impression shown above, where the Jinsui material has been pushed into the holes in the patient's gums.
This spike shape will be completely duplicated in the metal to form a post.
The Plasticine is rolled into a long strip and cut so that it appears on the slot on the back of the metal tray.
This way, in the next step, the plastic plate can be slotted correctly onto the metal tray.
"Important" impression I. e.
The one that contains the impression of the key teeth that require the crown is raised to make it horizontal and centered, and remains about. 1-
2 cm below the Plasticine strip.
Please note that the impression has been trimmed with a surgical knife to remove the excess impression material and to make the impression more flat.
The Plasticine is wrapped around the impression, and some holes are used to fill the center.
The top of the plasticine should be flat and the top should be consistent with the bottom of the slot on the back of the metal tray.
There must be no holes or gaps in the plasticine.
Next, insert a white plastic substrate into the drill.
The tip metal rod at the top is aligned with the drill bit below the base plate.
Silver metal trays are fixed on black metal blocks containing white substrates.
This will ensure that the impression is aligned with the white substrate below.
The black surface can slide around.
The metal rod above the die is consistent with the drill bit below the white substrate for guiding the drill bit to the substrate in order to make the hole in the correct position.
In the later stages of the process, the actors made according to the impression will be divided into several parts --
In this case, it will be 3;
The Crown part needs to be removable, so the casting needs to be separated on both sides of the place where the crown is installed.
Therefore, the place to put the hole must be decided in this step.
Depending on the size of each part, at least 2 holes need to be drilled in each part.
Next, the metal pins will be put into these holes to help with the subsequent relocation.
Insert a metal pin into the hole.
Please note that the Crown will be placed near the two pins.
Dental stone powder is mixed with water in a vacuum mixer.
When the tray is placed on the Shaking Table, the mixture is slowly poured into the impression to prevent the bubbles from being captured.
Bubbles destroy the resulting stone casting.
Pour some of the stone mixture onto the white substrate to prevent bubbles from getting stuck around the nail.
The white substrate is pressed in the slot of the metal tray to make sure it is pressed on the plasticine.
Another impression (lower teeth) is to fill the shaking table with plaster and put a pile of plaster on the table top.
When the pile is slightly solidified, so no more runny nose, the impression is flipped over to the pile, and the plaster is formed around the shape of the impression tray.
The impression must be horizontal and central.
The stone only needs to be used for the "important" upper impression (not plaster), as this casting is to be processed, so it needs to be harder and more durable.
When the plaster and stone set, carefully remove the plasticine and impression tray, leave you the plaster model of the lower tooth, and a stone model of the upper tooth connected to the white substrate with a metal nail.
This is the upper model starting from the top and starting from the bottom when the white substrate is removed.
Metal nails allow the casting to be removed from the base plate and then connected again in exactly the same position.
Remove excess stone from inside and outside the arch.
Then Polish and smooth the model on the side, basically making it decent and easier to handle.
The model was put back on the substrate and sawed into 3 pieces, requiring a cut on both sides of the Crown.
The edge of the gums, which is the top edge of the gums (gums) surrounding the Crown
The Crown needs to greet chewing gum there, marked in red.
The upper part of the stone part is polished into a smooth cone shape until the red line.
Apply wax to the top of the model using surface closures and lubricants so that the wax does not stick to it.
Then use a thin plastic column to help melt the wax fully fill the holes in the model, increase the strength and keep the wax column together.
A rough tooth shape is piled up on the pillars with wax.
There is enough space on each side of the wax to install the crown.
Note that the wax is uneven at the top as the v shape means that the Crown will have more pillar support and more surface area to connect the crown.
This will help keep the crown in place, although a strong bite/struggle will work in many directions on the crown.
If the patient has enough dental material to support the crown, these steps are clearly left out because the post is not required.
Instead, the grounded tooth looks similar to the wax shape shown above and builds a crown on it (see the next steps in Crown manufacturing ).
The wax Post is removed from the model and connected to the yellow cone through the gate (wax rod.
Everything in the wax will be surrounded by a special investment material and the wax will be removed leaving the cavity where the wax is located.
Sprue is a wax channel that, when removed, is designed to leave a tunnel from the outside of the investment material to the shape of the inner pillar.
The cone and gate are made smooth and round to transport the molten metal used during casting to the rear shape as smoothly and quickly as possible
Any obstacle creates turbulence and bubbles and slows the metal down.
It is not recommended to slow down the movement of the metal, because the metal cools very quickly and it cannot be set until the shape to be cast is reached.
The position of the gate on the wax column is important.
It has to touch the wax column in the largest/thickest part and then guide the metal to the path with the least resistance.
Mold the flexible tube on the yellow cone so that the wax column and gate are closed near the center of the tube.
A small number of debuts (good name!
) Sprayed on the wax column, this is to make it easier for the investment to flow on the wax to try and prevent the foam.
The investment material is mixed in a vacuum mixer and then slowly poured into the tube.
When the investment is set, take it out of the tube.
The cone is taken out and the cylinder is placed in the furnace in order to burn out the wax, leaving only one hole in the investment, just like the previous wax.
The investment cylinder is then placed into the casting machine to align with the Crucible (where the metal is placed.
Then close the Crucible and cylinder in a vacuum and the metal melts (you can see it in the lower right corner of the photo above ).
When the metal is at the right temperature (Ie.
Completely melted), pour the metal into the cavity of the cylinder.
The cylinder is removed from the machine with pliers and cooled.
The hammer is used to break the metal casting from the investment material.
Any excess investment will be removed from the metal.
Sand Blasting machine is used to ignite a series of fine particles on the surface of metal castings to clean and polish the surface.
The excess metal is removed from the casting, using a fine grade drill * on the metal column, such as a stone drill, to remove any burrs/irregularities and smooth the surface.
Since this can cause the post to get sick, bur is not used to remove any metal
Suitable for patients.
Check the column to see if it fits very well with the stone model.
* The drill is a grinding accessory for an electric phone that rotates as fast as a drill bit.
There are many different designs, different uses and different grades.
Now we start making crowns.
First, the cast wax is built into the shape of the metal base.
The wax must melt before adding the crown as it needs to be tightly adapted.
The edges around the bottom of the Crown must extend up to the red line previously drawn.
If the wax does not rise to the red line, the crown of the result will not meet the patient's gums, and this gap will allow bacteria and food to penetrate under the crown of the tooth, resulting in infection.
The blue collar on the inside of the Crown is the wall frame on which the porcelain layer rests.
The wax crown is then cast in metal just like in the previous steps of the post.
So now there is a post (to the left of the photo) and a metal sub-structure of the jacket Crown (to the right of the photo ).
The Crown is perfectly placed on the post, and there is a tiny and even gap between the two, used to hold them to the cement in the patient's mouth.
It is not shown in the previous steps, but before adding wax, use the spacer at the top of the post, so there is enough gap between the Crown and the post to accommodate this very thin cement layer.
The Crown is "degassed" in the furnace and sandblasted before adding an opaque porcelain coating that prevents the metal color from showing.
The lips on the back of the Crown are not covered in porcelain.
This metal lip is designed to support porcelain, increase strength, and keep clear, clean and clear edges.
Next, build and fire multi-layer porcelain in the stove.
The ceramic mixture is produced by mixing the porcelain powder with the liquid (usually water), which can be added to the crown with a brush.
Paper towels are used to absorb excess water.
Pink porcelain becomes yellow when fired in the furnace, used to represent the dark tooth material tooth quality, which is under the enamel of the natural tooth.
The white porcelain mixture becomes light and transparent porcelain when fired, copying the appearance of enamel in natural teeth.
The goal of dental technicians is to make the porcelain coating in the right shape, but need a larger size than the Crown.
This is because the porcelain will shrink slightly during firing.
The technician will use the photos to use the correct porcelain tone and build the layers in the right way to provide the same look as the patient's adjacent teeth.
Here you need a nice pair of eyes!
After firing, use a drill to grind the porcelain into the correct shape, so that the sides are consistent with the adjacent teeth, the curve of the teeth is smooth, matched with other teeth, and the size is correct.
The drill is also used to grind the details into porcelain to match the same tooth (front molar tooth) on the other side of the arch.
The lower teeth cast early with plaster are used to check whether the Crown is in the right position relative to these relative teeth and whether they are correctly combined.
Do not have early contact when biting/eating.
The last furnace firing procedure is used to glaze the crown and produce a shiny finish.
The metal collar on the back of the Crown is polished and finished!
Stains can also be used on the crown to add more specific details.
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