I have found the most common thread that exists to define the variance amongst end users is their optical impressions. This IS the most critical aspect of CEREC since it is the only means by which we input data into the machine to create our restorations.
This single factor, from the end users comfort level with taking optical impressions to their technique seems to define most aspects of their particular success and limitations with the system. It makes sense really, and ties in with the earlier thread to note that the ability of the operator to get optical images largely determines their use of the system.
How so? Well if one is using devices for years that are designed to obtain single opticals then logically they will be most comfortable with any method (correlation or database) which allows them to continue with this same pattern. Trying to use their comfortable methods, and specific devices for the now required multiple opticals which allow the creation of stitched together dies is cumbersome, and error prone enough for the practitioner to ‘fall back’ to their previous comfort zone.
As mentioned previously, curiously enough, absolute beginners seemingly pick up on taking the multiple images beneficial to 3D imagery easier than many with much prior exposure to single opticals. Therefore, its easily understood that many of these complete beginners are also capable of doing methods like database/antagonist that require these multiple images (and highly accurate ones) with a surprisingly quick learning curve.
Perhaps, as mentioned, they dont have to repattern any pre-existing methods that many with experience have?
Nonetheless, examining closely a few basic guidelines one can easily create very accurate optical dies, from very consistent optical impressions. This removes this necessary ‘liability’ from the system and allows enough clean data and information to the system to avoid many of the defined problems and issues that seem to exist for those having difficulty getting the successful results that others routinely do.
The following are the hardfast ‘rules’ that I personally use to create multiple opticals for CEREC 3D. While this is NOT meant to be posited as THE rules for taking opticals with CEREC, or even implied to the THE official rules, etc. they ARE what I personally consider, and are what I have taught to others who also have routine success with the system. There are a few products (which I have no vested interest in promoting other than their apparent value as stated) which I find invaluable to obtain the results, and a few methods/considerations which I also advocate (regardless of any other ‘official line’, etc.).
I mention what I do for one simple reason, it works!…and it works well!
First off Isolation is KEY..I have found no better device for CEREC opticals than Isolite (www.isolitesystems.com) This device is so beneficial to this method, its as if it was made for this purpose. First off, the Isolite is easily placed, removed, replaced with a great deal of consistency in relocation (helpful between ’sets’ of opticals for orientation, alignment, etc.) Secondly, its comfortable ans soft, making it easy for the patient to wear for these longer CEREC procedures. Third, it drafts the CEREC lens with high volume suction preventing ANY fogging (a known and perplexiing problem with CEREC opticals which greatly reduces possible accuracy). Fourth, it protects these expensive lenses from damage, being impossible to ‘bite the lens’, or bump it into a hard surface which could scratch/chip these expensive pieces (each around a thousand USD). Fifth, and most significantly is the ability to create a reproduceable platform for the placement of ones finger along the buccal corridor. This ‘fingerstat’ allows one to ’slide’ the camera along your positioned finger to -dramatically- reduce if not eliminate any rotation, yaw, twisting, or up/down movement of the camera between the multiple opticals.
The benefit of this cannot be overstated. Simply put it allows to EASILY obtain VERY clear, concise, fluid, and accurate -multiple- optical impressions for the CEREC system. Sliding the camera along ones finger might seem incredibly ’simple’…and it is!… thats why its so easy to teach. More importantly is that without the camera ‘moving’ excessively between the multiple opticals in these axis it makes utter sense that the computer has little difficulty in accurately ’stitching’ them together…and therefore accurately creating a restoration (even multiple restorations).
Next, I consider the fewest possible opticals that will give the computer enough information to accurately generate the results..seems logical enough. For many however, that has been a ‘call to arms’ to then take only one optical…just like the ‘old days’. My positionis simple..IF one optical gives enough information (including adjacent teeth) than one it is…if not, then I take the minimum to get that. I personally like to capture at least 1/2 of the adjacent teeth…why? many reasons. First off, it allows me a reference to design and alter any proposal to accurately address height of contour, emergence profile by using that information gathered from the adjacent teeth. Secondly, the ability of the system to -accurately- position the antagonist against the preparation is apparently much greater (with the adjacent ‘information’ to work with). Even IF the system cannot ‘match’ it then gives the operator a LOT more, and clearer information to manually match with latr if necessary. Again, IF the data input is ‘clean’ the ‘liability’ of more optical impressions becomes insignificant if not irrelevant.
I typically position the target tooth in the lowest extreme of the optical screen, avoiding any undercuts, etc. with the image using the ‘fingerstat’ and Isolite to get as clean input as possible. Make sure that you show as much of the ‘adjacent’ structures as possible without ‘cutting off’ ANY aspect of the preps margin. Then position the same target (again sliding along ones finger) in the top portion without cutting off the margins. So BOTH opticals show ALL of the ‘target’ tooth within the frame. Minimally for consistency, I take routinely 2 prep images…2 antagonist images for a single tooth. I will take 3 prep images, or maximally have taken 4 for entire quadrants. With ‘multiples’ make sure that for each independent ‘unit’ that one simply ‘centers’ or otherwise guarantees that at least ONE of the opticals captures the entire margin of the individual tooth.
Using the same ‘position’ rules, and trying to additionally ‘match’ camera frame to camera frame with the shot of the prep to the shot with antagonist record in place, I take the antagonist images (cutting with BULL easily facilitates this). Its common sense really to think that IF the information is SO ‘clean’ ‘going into the system’… the computer should (and routinely does) easily ‘match’ them up to get an accurate die to work with. I STRONGLY believe that this is KEY to why I (and others I have taught these very methods) seemingly have VERY LITTLE difficulty in getting excellent restorations from the machine..This should be closely analyzed to see if and how it factors in the wide variety of ‘issues’ others apparently have. If so the solution is quite simple..instead of having to involve elaborate schemes, etc. to ‘accommodate’ their own personal method which MAY be the problem to begin with?? Personally I have NOT spent the time to analyze why others have their problems, being far busier showing others how to successfully and consistently achieve these results instead. I leave that to others so inclined, but its hard to overlook the obvious IF it works…do it!!! apparently what others ARE doing does NOT deliver this same accuracy and consistency…again to each his own.
What I personally recommend HAS been successfully used, and implemented in real world clinical environments throughout the world…I share the ‘basics’ of that here. This is based on the widely popular trimming of the antagonist record mesial/distal using the Rule of BULL. Cut mesial distal the Buccal aspect of an upper prep…lingual aspect of a lower (obviously ‘reversed’ for crossbite cases) This typically simply removes excess registration material which serves no purpose anyway. More significantly it makes a VERY CLEAR ‘line’ which to follow/see/orient as additional information while taking these optical impressions. I try to cut back as far as practical without altering the ‘information’ the record provides with the guidance of the opposing occlusion. This often ‘exposes’ at least the margin of the prepped tooth (in a typical occlusion) and that -further- allows ‘orienting’ the individual optical images to ‘position’ them as consistently as possible ‘between sets’.
There are many different ways to ‘cut’ the registrant…thats the reason I cut it the way I do. Its a VERY elegant ’solution’ with its ‘core’ being one simple tenet…GIGO…IF ANY method ‘works’ to allow for clean data input, it will be timeless…as this one has proven to be. I first evolved cutting the registrant using BULL with R1000 -long- before any association with developing CEREC sw with Sirona….interestingly enough while many others perpetually complain of their concerns in getitng this method to ‘deliver’ for them, I continue to use the very same ‘methods’ with the very latest version being developed today (a not yet released beta version). Again, its based upon simply delivering pure data to the computer…thats timeless.
Further, cutting the registration as such does not eliminate the potential functional information in a normal occlusion which dictates that cusp tips rest upon the marginal ridge of the opposing occlusion which easily happens if one cuts Buccal-Lingual as some advocate instead. Further, realize that ALL ‘data input’ to the system is entered as the optical impressions we take. The ability to ’see’ the position of the tooth beneath the record (as BULL trimming yields) in addition to the very apparent ‘line’ the cut positions on the image screen GREATLY reduces the ‘variance’ between images, and further provides valuable ‘information’ for the computer itself to accurately ‘match’ the image sets ‘together’ to yield an accurate ‘die’ …and accurate restorations…
Since I advocate trimming with BULL, I obviously also advocate removing the registrant to cut it. This curiously has garnered a range of beliefs, methods, opinions. Personally, I dont buy those arguments, or positions. The careful (and extraordinarily easy) use of the registration material I use is created to be used by removing the material from the mouth (and accurately registering models extraorally together). Using Exabite 2 NDS, or Clinicians Choice Bite registration makes one seriously wonder if others are having so much difficulty with ‘distortion’ or reinsertion error, etc…perhaps they need to try these materials instead? since that is completely a non-issue when using those materials.
Notably these PVS based materials are ‘thixotrpoic’ (they flow, but have ‘gel like’ properties preventing displacement/sag) I place the registration and wait until its set enough to not have a fingernail ‘mark’ the surface. then removing it its VERY easy to cut accurately as it continues to ’set’ where it becomes quite rigid (cutting it too late will lead to a tendency to crumble instead of cut clean). Cut the registration using BULL…remove any ’spikes’ or other excess which might interfere with imaging. By the time one replaces the registration it is rigid enough to all but ’snap’ into place….they NEVER ‘move’ and witht he BULL ‘cut’ one can EASILY –SEE– ANY movement and displacement of the record directly over the prep itself! Therefore its EASY to –SEE– if its FULLY seated, moving, etc. which it routinely seats -extremely- intimate, and extraordinarily well…again no ‘mystery’ as to why the occlusion of those I have taught these methods to do not seem to have the same ‘issues’ that others do…IF the system CAN match the images…no surprise the restorations will accurately fit.
A curious aside…why is more effort seemingly spent trying to understand why a select group is having difficulty…than to understand why a select group is NOT having those same difficulties? Would it not help -everyone- to perhaps ‘figure out’ why those who are having success actually -do- and THEN create recommendations, positions based on that?…instead of creating positions to hopefully ‘fix’ the ongoing problems of those …who even with those recommendations -still- have problems? I do digress;)…
So, overview…I -personally- start by prepping the tooth…take a registration, remove and cut it with BULL…replace it…powder the area…take opticals of antagonist -first- Simply remove the registration, powder the small area previosly covered by the registration and take the prep opticals…very fluid, very ergonomic, very accurate…so are the results!
Ray Becker
7 responses so far ↓
1 Chris Winterholler // Nov 25, 2005 at 10:18 am
Ray. THe last paragraph said it all. This is by far the most efficient method of database / antagonist as I have tried Armen’s Trick with the Luxabite placed on the tooth and imaged before prep and then repowdering the whole thing after the prep. It works but is not time efficient.
Are you also in agreement that if the OI taken with the Long axis if the Tooth, Cooincident with the path of insertion of the prep, coincident in angle to the Camera that all of the auto occlude adjust modes can be left on to do their job without much editing required.
I use this all the time but it would not be possible to use the machine on auto mode if my OI’s were junk.
Chris
2 Ray Becker // Nov 28, 2005 at 10:07 pm
Hi Chris,
Thats a great point when taking opticals. I totally agree with your assessment that keeping the long axis ‘consistent’ throughout opticals is huge in accuracy. This was pointed out to me with a very good analogy by Mark Fleming as keeping the draw as though one is working a bridge prep draw with multiple units…great analogy.
One can easily ’scan’ the tooth prep(s) before taking the actual opticals and even get ‘practice’ with taking the multiple opticals using the finger as a ‘guide’ to slide along (the ‘fingerstat’ mentioned) and from that few seconds one can then determine a great deal of valuable information for the subsequenty opticals to be taken, including the best long axis to consistently keep between individual images as you mention.
I have found that even though the system has a pretty amazing capability of taking images that are slightly askew in one axis or another and then still creating a die… it just makes sense to ‘enter’ as ‘clean’ data as possible since everything is ‘built’ upon that input.
I have noted from watching many others and their techniques that curiously the same persons having the most difficulties with a wide range of nuances in everything ranging from proposals to contacts, occlusion, images being accepted, etc.,etc. seem to also employ ‘technique’ which either minimizes the potentially valuable information possible with highly accurate multiple opticals, or they use methods which are not as optimally clean as they could be.
People may not like to hear that its them and not soome problem with the sw, but I strongly have witnessed that to be the case. Those open minded change to improve their technique..the others blame the sw, or a shortcoming with the system, unwilling to admit its maybe their technique.
The more ‘askew’ the opticals, the more necessarily ones results logically relies heavily on the sw itself, and easily one can understand that with any system the more error, no matter how small initially it compounds ‘downstream’.
Thats the ‘logic’ of the mentioned system, as you say…even with a wide array of other methods, its very elegant ergonomically (never ‘covering’ the same ground twice…always timely moving to the end result) is designed to be highly accurate, and efficient in a real world setting. The reason I believe its so ‘elegant’ (in the truest sense of that word as it relates to computing) is because its so straightforward and simplistic in implementation, BASED on just clean input as possible.
As you note, and I mention, the benefits are many and varied. The most significant aspect I have noted is reproduceability. I have witnessed first hand so many absolute beginners take very accurate quad impressions/dies… almost immediately that -something- simply has to be there.
Amazingly, and astonishingly I have also experienced that even with the very latest developmental version of the sw (as I know you also are using) that I am still finding it the best way to get consistently accurate results from db/at.
Asking myself why, I can only surmise its based completely on one simple tenet GIGO…all of its ‘principles’ are based on getting VERY accurate and easily stitched images, logically this puts less ‘burden’ on the sw…they stitch quicker, and generate more accurate results very consistently.
That said, its not a panacea, just a method with a strong and growing base of users. What I recommend is that persons try (and completely try -exactly- as described) the methods such as this. IF what one is doing works for them…continue…
But if they are not experiencing the same results others are having try another one that does. I make a STRONG suggestion with that said. Dont ‘cherry pick’ a method and only do some of elements then in frustration suggest that ‘I tried it…didnt work for me’…come to find out usually only one ‘aspect’ was actually honestly employed and done as prescribed.
I mention tools like the Isolite, etc. simply because they have proven to make this method absolutely predictable. When I witness people doing it with all the ‘tips’ mentioned surprisingly they too then experience a FAR better CEREC experience also…to me thats what really matters most.
You are so correct to note that its VERY fast, clean, fun, and predictable when the input is ‘pure’ Chris!
Ray
3 Chris Winterholler // Dec 1, 2005 at 11:49 am
Ray,
Its too bad that this is probably a discussion between two people. THe hardest thing I have encountered teaching the Fundementals of CEREC is the incredible subtlety of success dependent on Good Camera Technique.
Once people get this principle that you line things up, Take the same shot at the same angle, pitch, roll, and yaw. THe machine turns in to a Gattling Gun for Crowns. SO many get lost in the design modes for inordinate amounts of time that they get dissillusioned with the machine. I hope with your resources you make another one of those DVD’s about this very subject.
Always good to visit with you,
Chris
4 Ray Becker // Dec 1, 2005 at 1:12 pm
Hey Chris,
Actually a lot of people advise me they are really tired of the ‘baggage’ apparent associated with completely unmoderated format(s) just to get a ‘one-liner’ tip every once in a blue moon…
I finally took up Tom on his repeated requests and find/refer many here for the very rich resources it yields, complete and thorough references to topics, certainly the perspective of the authors, but respectful of that as well.
Many simply want to hear what someone who has proven their capacity and mettle in a particular arena has to say, especially if they freely, and willingly share it for the benefit of others.
It seems a great vehicle to get unfiltered (and thorough) perspectives from those who have evolved, invented, created successful and valuable materials, techniques, methods for busy clinicians.
I will see how it works out, but its designed to get a point out there, thoroughly, on target, complete without the ‘atta boy’, ‘I agree’, AND the unfortunately sometimes ridiculously nasty ‘opinions’ etc. from those who just cant seemingly moderate themselves to common respect and decency.
As you note there is quite a bit to ‘understand’ and consider with ANY method, spelling that ALL out takes time and effort from the author, so its incredulous to believe a one-liner can help one with a technique such as this… but then again…ever note that those delivering ‘one-liners’ often are the same ones NOT trying to ‘advance’ their methods…just ‘troubleshoot’ the same old same old…
The results/benefit of successful use of db/at are quite dramatic and apparently FAR more ’significant’ than any ‘one-liner’ can possibly understand;)
In other forums one spends just as much time hearing others opinions (NOT to be confused with constructive dialog which COULD potentially have overall value) that getting complete messages out is difficult if not impossible.
So many write me on the side saying please just ignore them (sadly THEY write on the side because of the uncomfortable ‘environment’ that negativism naturally creates and fosters…too bad really). Universally I hear “I appreciate and value your help”…which in the past I did simply ‘deal with it’…. Here its far easier to share MY valuable time to help others…without that ‘liability’…
This format is not ‘closed’ to questions, as your post notes, but its more aligned to archive, arrange, and ‘reference’ complete thoughts, without the ‘attaboy’ chattiness. So having ‘referred’ many who ask the same questions to the complete ‘overview’ here makes it more a ‘reference’ than ‘chatty’…certainly used and viewed though.
I am told it helps to have the complete ‘thought’ available to reference…thats what DentalBlogs apparently is about…
The absolute amazement people get when they FINALLY ‘get it’ is as you note Chris…a real revelation…THOSE supporters are the same ones who ‘lurk’ other forums and tell me a wide range of ‘reasons’ they believe the naysayers just cant/dont/wont ‘get it’…
Unlike those individuals, I think doing it -either- way is perfectly OK!…just as you and MANY others note, this way ABSOLUTELY can and does work, and well! As you also note it opens up HUGE doors, and potential for the technology!
Ray
5 Benjamin Hornstein // Mar 9, 2006 at 7:54 am
Ray,
Could you please forward information about your DVD’S.
Thanks,
Ben
6 melinda // May 12, 2006 at 10:15 pm
I attended a CEREC 3 lecture today and am wondering if the average learning curve is measured in months or years. The speaker mentioned that COSTCO/PriceClub (similar to Walmart) will be hiring dentists for their stores to sell one-day-crowns at $300 each for members - also offered is $150 Zoom whitening. When this becomes popular, the general dentists’ crown fee will have to drop to be competitive… then how will we repay our $116,000.00 loan? Also the unit has only a 3-yr. warranty, and the extended warranty does not cover parts ( ie. thousand dollar gears). With my luck, I would be the one to purchase the German dud and it would malfunction the day the 3 yr warranty expired. Are there other draw-backs?
7 Nathan Muirhead // Sep 22, 2006 at 9:43 pm
Not just a two way discussion! Thanks Ray and Chris for your thoughts. I’m curious about what powdering tips you might have for a beginning user of CEREC as to what powder brand you like the most, tips on how close to powder how long, how to correct etc.
Thanks for this great resource
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