Efficiency and Accuracy in Denture Base Processing
Dennis Urban CDT
As we look at where the dental laboratory industry stands with acrylic denture base processing and as I travel around the country lecturing and training on removable technology , I find that removable dental technicians still advocate the old reliable technique in which removable technology was built .
Press packing is still the most widely used method in acrylic processing followed by injection and then by pour acrylic techniques . The success and accuracy of these techniques depends on the right materials and of course the expertise of the technician . I am a big fan of heat cured acrylic and have also been a longtime advocate of microwave curing . There are many differences in quality on many of the heat cured acrylics out on the market . I judge an acrylic by natural shade , the strong bond between denture base , flexural strength , impact resistance , bond to denture teeth and finishing and polishing qualities . I also look for a low shrinkage rate in an acrylic .
Diamond D ® from Keystone Industries is the one acrylic that has been consistent in all of these qualities over the years . Those who know me in the industry know that I do not compromise when it comes to quality . I am only interested in giving the patient the best possible case with the ultimate in aesthetics and function , so when Keystone Industries introduced their new Tecnoflask for microwave denture curing , I was very excited to test out this flask with Diamond D ® acrylic . The results were phenomenal . I got the same quality results time after time . I can now cure a denture in 4 minutes in a 500w-700w microwave oven utilizing Diamond D ® 20 minute monomer or cure for 9 minutes using regular heat cure monomer . Made of the best thermoplastic material suitable for a conventional microwave oven , the thickness and overall shape of Tecnoflask makes it stand out from competition . Tecnoflask ’ s toughness and resistance makes it safe against continuous pressure and high temperatures with no damage done to the mufffle . I use these flasks every day at our lab with peace of mind that every case is going to be a quality one . You can even cure metal partials , hybrid and bar cases with microwave technology . Another plus is that the acrylic is being cured from the inside out resulting in virtually no free monomer after curing . This is very important for patients who have a sensitivity to monomer .
The following is the Tecnoflask Diamond D ® microwave technique :
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1 ) Wax up denture for finish in the normal manner . ( Figure 1 ) |
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2 ) Invest denture in bottom half of Tecnoflask in a half and half mixture of plaster and stone . ( Figure 2 and 3 ) |
3 ) After gypsum has set up , Vaseline all gypsum areas . ( Figure 4 ) |
4 ) Attach top half of flask and tighten all bolts . ( Figure 5 ) |
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5 ) Mix up type 3 gypsum and vibrate into flask , filling entire flask . ( Figure 6 )
6 ) After gypsum is set , remove bolts and insert flask in microwave and set timer for 1 minute and 30 seconds . ( Figure 7 )
7 ) Open flask , remove the bulk of the wax and boil out the remaining wax . Clean all waxy residue off teeth and prepare teeth by roughening ridge lap of teeth or if desired make diatoric holes for added retention . ( Figure 8 )
8 ) Paint on Diamond D separator ( 2 coats works well ). ( Figure 9 )
9 ) Mix Diamond D heat cure acrylic and 20 minute monomer according to manufacturer ’ s guidelines . ( Figure 10 )
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10 ) When material is ready to pack ( comes away from jar without sticking but not at snap stage ), pack into flask and trial pack . ( Figure 11 )
11 ) Make sure metal protector is placed on top of flask when packing . This will ensure longevity and protection for the Tecnoflask . ( Figure 12 )
12 ) Open flask , remove excess and add more acrylic . After pressing , remove excess again , paint model with Diamond D ® separator , close flask and tighten bolts . ( Figure 13 and 14 )
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13 ) Place in Microwave and cure for 4 minutes . ( Please note , if using heat cure monomer , cure denture for 3 minutes at 40 % power , 3 minutes at 60 % power and 3 minutes at 90 % power . Microwave can easily be programmed for all three power levels ). ( Figure 15 )
14 ) Take flask out of microwave and bench cool for 20 minutes . Immerse in cold water for 5 minutes and deflask . ( Figure 16 ).
15 ) Check occlusion ( Figure 17 ) and finish and polish denture ( Figure 18 and 19 ).
Denture technology has been making some significant advances in materials and technique ’ s including more natural looking and wear efficient denture teeth . With the recent introduction of digital technology , we are likely to see even more changes in the way we approach removable technology . Keep in mind that even with digital technology , a denture base resin is still being utilized whatever the method the digital denture is being made . All in all , utilize materials and methods which are consistent in producing quality . Show off your technical talents by bypassing methods which will sacrifice doctor and patient expectations and keep patient satisfaction in mind .
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