hello and welcome to chair side life I'm Megan strong and I'm will Schmitt registered dental
assistant here at global dental and today's show is exciting work kicking off a brand new
series with dr. Qi and in this first installment he's addressing some of the common problems and
solutions that the dental team and then also the lab kind of faces women taking digital interaural
scans alright well in this first episode he's scanning number 30 just the quadrant he's gonna
take a look at it and see if it's ready to go to the lab or to design with his own in office
mill but first we're gonna talk about occlusion margins occlusal clearances and the contacts well
that's exciting let's not wait another minute let's get to it so once all of your scans have
been captured whether it's a fixed prosthesis and a liner or removable appliance it's very
important that before you send that case off to the laboratory that you analyze the entire model
to ensure that all the data points are captured accurately if anything is missing that will lead
to restoration or prosthesis that just might not fit correctly it might be loose it might
be too tight the contacts might be a lot heavier than you would want them to be so truly what is
the lab looking for so that's what we're gonna review in this next segment how do we analyze
the entire model together before you send it off to the lab for that accurate fitting restoration
or prosthesis so you've captured your digital impression now before you send it off to the
lab or to whatever service you're sending the STL scans to you want to make sure you analyze your
digital impression your digital models first to ensure that you have all of the critical
data points that the lab will need to create a precise fitting accurate restoration so we
have our preparation in this case we have a single unit crown prep on tooth number 30 the lower-right
first molar you can see it here and the entire quadrant so starting off with the entire model
with most of these type of cases single unit posterior restorations or preparations we want
to scan from the last tooth forward to at least the canine I recommend at least to the canine or
cuspid so that you have data points extra data points for yourself and the dental designer to
create anatomy within the restoration that is true to form for that patient also those extra
data points to the mesial and distal will allow a more accurate recreational or generation of the
bite registration for the patient without those data points over the adjacent teeth to the prep
the scanner is going to have a much more difficult time establishing the patient's occlusion so we
have most of the teeth that we want again the entire quadrant of the canine all the way back
to the last tooth in this case number 31 what areas of those teeth do we want to capture so
we want to make sure that the teeth are visible on the occlusal we have most of the data on the
occlusal the lingual surfaces are filled in well and also the buccal surfaces are filled in well
and also the gingival margins that just allows for a clean accurate impression of our patient
now those surfaces are certainly critical but in area we can't ignore will be the contact surfaces
over the adjacent teeth so in this case number 29 and 31 the two teeth next to the preparation
those contact surfaces next to the prep also have to be filled in if those are missing the
restoration is most likely going to be too wide mesial distal e and that would mean a lot more
adjustments or you on your end when you're going to try to seat it on the patient so making sure
that's filled in will be critical next probably the most important aspect of the entire quadrant
scan for the prep is the prep you want to make sure the occlusal of the prep the axial surfaces
of the prep and the margins are all filled in so they're not missing any critical data points
within it if there are any holes within that you definitely want to capture that and fill that in
now for the margins you want to make sure that the margins are visible they're clean and for those
equitable or even sub gingival margins that adequate retraction was accomplished whether
you're using laser you're using retraction cord or they have the retraction pastes some method
to move the tissue away from the preps so that the margins are visible if you cannot see the
margins at this point on your digital impression how can you expect someone else down the line the
dental technician to know where to position the margins so it's going to be very critical that
those are also visible within your digital model so analyzing the entire model making sure you that
you have accurate data points over the adjacent teeth the contact surfaces of the adjacent teeth
and the entire preparation nothing's missing everything is filled in correctly and the
margins are visible that's how you can ensure that your print model is accurate enough for a precise
fitting restoration to be created on it so for the opposing you can see here on the lower I scanned
again from the last tooth to at least the canine on the mesial side we want to try to establish
the same number of teeth on the opposing so you can see I have number six scanned in here all the
way back to number two so if we just analyze the opposing the upper model here we want to
ensure that most of the occlusal and the buccal and lingual surfaces of the opposing model are
captured it's going to be very difficult for the dental technician or even for yourself if you're
designing these restorations in office chair side it's going to be hard for your design software to
know how high to build the restoration if some aspect of the opposing dentition is missing so
again making sure the occlusal buccal and lingual surfaces are filled in appropriately and that way
we can establish an accurate bite and occlusion for that restoration now in this restorative case
you can see I'm missing a little bit within this gingival embrasure on the buccal between 12 and
13 also on the lingual for this particular case a restore situation is not critical on
the opposing area but if this case were to be used if it were a full arch stand if it were
to be used for removable appliance like a sleep appliance certainly with the liners clear liners
you want to make sure that all of the areas within the embrasures the gingival embrasures
are also filled in but in this case a restorative case most of the occlusal buccal lingual will be
sufficient so once you analyze that information many of the scanners today have some additional
features so in this case the eye taro element has an occlusal clearance function so when I activate
that occlusal clearance function we can see some areas on the right here or this area here that
has a color map it will reveal on the preparation how close it is or how far away from the opposing
that prep is there's a scale function for the eye taro I like to change the scale usually it will
default to the last or third option where the range of revealed colors is between one point
one to two point three millimeters of clearance I like to change that to the middle option of half a
millimeter to one and a half millimeters and what that will do is just change the areas that are the
colors that are on the teeth and right now I know with that setting if there are any colors that
are on the prep it means that the prep is less than one and a half millimeters of clearance so
clearance distance from the opposing so at that point you can make the decision whether or not
to reduce a little more on the patient and most likely you would need to most of the materials
that we use today whether through the lab or chair side like the lithium silicate glass ceramics
even with brookster restorations one and a half millimeters is what we're shooting for to allow
for adequate strength and also for the technician or the design software to create occlusal Anatomy
that conforms well to the patient's dentition so it will give you more natural-looking Anatomy on
your durations so that's a great feature and with digital scans before you send it off you have the
option of maybe making edits to the digital model you can go back you can delete areas
that are not reduced enough you can delete areas that may not have been retracted enough that's
one of the most wonderful aspects of a digital impression system being able to edit your digital
models before they get sent off to the lab so that's how you want to analyze your models it's
not just a matter of going through the sequence positioning of course all of that is important
the fundamentals of keeping things dry positioning where you need the camera to capture the data but
analyzing the model is going to be an important aspect of using your digital impression system
to ensure that you're getting the most accurate representation of your patients dentition for
that precise fitting restoration or appliance that you plan on using thank you so much for
your time well thank you so much for that dr. G and stay tuned for future episodes in this
series or dr. Qi is going to dive deeper into common problems associated with these types of
stands well I can't wait for that but for today well wrapped up here so on behalf of everyone
here at global dental thank you so much for watching we'll meet you right back here next time