Januari 19, 2017
glidewell laboratories is a massive manufacturerof crowns, bridges, implants and other dental lab products. they’ve developed an assemblyline workflow --based around ember 3d printers--for creating crowns and copings. â here isâ theirprocess for making â porcelain-fused-to-metal dental crowns.they start by 3d scanning a dental impression, which yields a 3d mesh of the patient’smouth. next, a dental technician inserts a model crown into the mesh of the mouth. theyuse specialized software to orient and size the crown. the red regions indicate occlusions-- this is where the model would collide with other teeth. the technician pushes and pullson the mesh to make sure the tooth will fit. this digital mesh is sent to a second technicianwho performs quality control. this is similar
to the previous step, but this technicianis more experienced and makes sure that the shape of the tooth looks natural. next, themodels for the crowns and copings are prepared for 3d printing on ember. a tech uses specialdental software to add supports onto the model. then the models are tightly arranged in aplane. this nesting allows many crowns to be printed at once improving the efficiencyof the process. now this collection of crowns is sent to an ember printer. a tech startsthe printer. the print time is typically around 40 minutes. glidewell uses a specially formulatedresin, which will completely burn out later in the process. after the print is done, atech removes the build head from the printer, scrapes off the print, washes it in alcoholand dries it with an air gun. then the print
goes through a post-curing step under a uvlamp. because the print can have multiple crowns from multiple patients, they createa sheet for each print. the sheet has an image that matches each crown and coping on theprint with the specific patient. for example, the image labels crowns number 1, 2 and 3,which match these crowns on the print and these cases for a patient. the 3d printedcrowns are removed from their supports and are packaged into adorable tooth-shaped containers.a technician takes a 3d printed crown and skillfully applies a thin wax coating on print.this coating smooths the microscopic roughness from the printing process and will yield avery shiny finish on the final part. another technician sprues the crown. they use waxto attach it to a stem. this will create a
passage for metal to flow into the crown duringthe casting process.the sprued crowns are put into a mold and a technician mixes upthe investment material, and pours it around the crowns. when the investment is completelyset, it’s put into an oven until the heat completely vaporizes the wax and 3d printedcrown, leaving a crown-shaped void inside the investment. directly from the oven, theinvestment is inserted into a vacuum casting machine. already inside is a precious metalalloy. the machine flips over and a vacuum pulls the molten metal into the void space.the casting is removed from the machine and left to cool.in a process called divesting,a technician breaks apart the investment with a hammer, and uses an air gun to remove anyremaining pieces of investment.he cuts off
the sprues…. ….and weighs the castingsto determine the price.these casting then go through a polishing step. this metal castingwill form the substructure of the final crown.next an opaque layer is applied to the casting.it acts like a primer. it covers up the grey color of the metal and also increases adhesionwith the porcelain layer. to create the porcelain layer, an “anatomical top†is first 3dprinted on ember in castable resin -- printed at the same time as the coping. the top slidesonto the opaqued casting. the casting and top are then attached to a wax sprue. thepart is surrounded again with liquid investment. after it solidifies, it’s put into an ovenwhere the wax and 3d printed top are melted out, leaving the metal coping embedded insidethe investment. a special ceramic is shot
into the mold, filling the empty space. aftercooling, the investment is removed. the metal substructure is now fused to the porcelaincoating. â they remove the sprue and—the crown goes through some finishing steps, includingdetailed painting and glazing, which gives the crown a natural tooth-like appearance.it is now ready to be shipped back to the dentist who will place it in the patient.thank you so much to glidewell laboratories who produce roughly 1000 crowns, copings andanatomical top units 3d printed on ember per day. it was so much fun working with you all,and it was incredibly instructive to visit your labs.so, if you’d like to learn more about using 3d printing for production, please subscribeto the channel. and to learn more about glidewell,
check out their youtube channel. they havelots of useful videos. thank you so much for watching and have a great day!
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