hello welcome back to another episode of cherish at live I'm dr. Justin Chi for this episode I'll
take you through one of my cases where the patient is unhappy with the aesthetics of his maxillary
central and laterals he has composite bonding resin on these surfaces that were placed due
to a trauma as a teenager we want to enhance the aesthetics of these by removing the old
composite and replacing them with obsidian lithium silicate veneers let's take a look
we have a 30 year old male patient that presents with composite bonding on the labial surfaces of
his maxillary central and laterals he's unhappy with the aesthetics of the resin that was placed
during his teenage years after he suffered a trauma to this area composite bonding was a
great option for the situation but can be very technique sensitive to avoid appearing dull and
monochromatic not to mention extremely challenging to create natural contours using a direct method
some of the composite is discolouring and breaking down between the Central's and also overhangs with
the restorations along the margins are causing gingival inflammation especially around number
7 & 8 the plan for the patient is to replace the old composites with obsidian lithium silicate
veneers before the prep appointment I sent impressions to our fixed department where they
designed a digital diagnostic wax up to help us on the clinical side know if there are any
possible limitations once the designs are approved they then send the digital designs to the bio
temps Department to fabricate Provisionals from those final designs you can hear dr. Muir Shawn
explained this process in more detail in episode 196 we will now begin the procedure with local
infiltrations to ensure our patient is comfortable starting with a coarse grit round ended tapered
diamond I first place vertical depth cuts through the old composites until I reached tooth structure
since the teeth are in a good alignment with the labial surfaces near where we plan on restoring
to the goal is to achieve an even amount of reduction along 7 through 10 I'm aiming for half
a millimeter chamfer at the margins and increasing that reduction to about point 8 millimeters along
the middle and incisal thirds once the old restorations are removed I place a triple
zero cord down in the sulcus to help push the gingival margins out of way the gingiva usually
moves apical e at least about half a millimeter this is really important for any anterior crown
or veneer to not only avoid inadvertently damaging the soft tissue but to also hide the restorative
margins slightly sub gingival once the gingiva rebounds i position and refine the gingival
margins only after the placement of the cord I used the same round in a tapered diamond to reduce
the prep so the margins run along the soft tissue equitably the tip of this bur is approximately 1.2
millimeters in diameter so I run it along the margins until nearly half of the burr is placed
into the tooth this will help create a clear chamfer along the margins and allow for a uniform
thickness of the final restorations in these areas to follow the mesial to distal curvature of the
anterior teeth I run the tapered diamond bur in approximately to a depth of about halfway being
into the contact area we are planning to lengthen the teeth so I flattened the incisal edges and
terminate the margins at the incisal lingual junction to include the entire incisal edge
within the preparations as with any all ceramic preparation we want to round off any internal line
angles for ease of fabrication and to ensure the final restorations are well adapted to the teeth
with minimal internal stress with these veneer preps the main sharp internal line angle is found
at the labial incisal interface so here I'm using a Venus super coarse composite polisher at about
10,000 rpm to round over this transition to have a smooth path of insertion for the veneers from the
facial direction i and all the incisal parts of the prep cervical e from lingual to facial when
the preps are completed I place a second layer of cord into the sulcus to push the tissue utterly
away from the teeth here I'm using a size two and using gentle pressure to push the cord into
the sulcus and then rotating the instrument out to lock it in place if you're having trouble getting
the core to seat go down a size until you find one that can see adequately within the sulcus the
cord should be seated into the sulcus without much force as we want to avoid any potential
damage to the attachment I always wait at least five minutes for the cord to provide the desired
retraction once the time has elapsed I remove the larger top cord while leaving the smaller cord in
place now we have adequate separation of the heart and soft tissue for the light body and pressure
material to flow into this is really important to allow lab technicians to see where the margins are
located after the impression is taken I try in the bio temps to verify that there aren't
any hang-ups along the margins when I verify that they can be seated in the correct position I then
clean and dry the shells really well and then realign the temps with dual cure basic rule 10
materials here I'm using tough temp by pulp then using a technique I picked up from USC dean dr.
avi scheisse Don I flowed the material along the margins first like a light body impression
material and then seat the shelves I found this to help minimize bubbles along these areas I
applied a thin layer of Vaseline to the preps to aid with the removal after they're cured one of
the most challenging situations when provisional izing veneers is keeping them in place while the
finals are being fabricated there's no temporary cement that I'm aware of that can keep these in
place and we don't have any mechanical retention to rely on so I found the only way to hold these
on is to bond these in at the center of the labial surface I spot H with phosphoric acid and about a
2x2 millimeter area on the labial surface of each of the preps I then cure a bonding agent directly
where I edged and then place a small amount of camouflage flowable composite on each of these
areas and then seat the Provisionals this is the only way that I've been able to successfully keep
these in place after the Provisionals are bonded into place I'm smoothing out the lingual margins
with a composite polisher just so these areas blend in really well with the tooth surface I then
use a fine diamond football to adjust the high spots on the Provisionals while carefully avoiding
the tooth structure which could certainly alter the margin position when it comes time to removing
the temps I place vertical depth cuts until the acrylic is thin enough where I can see the color
of the preps showing through I avoid cutting entirely through the Provisionals with the high
speed so I don't inadvertently mutilate the preps beneath when the material is thin enough I twist
with the Christiansen crown removal tool until it breaks the temps apart for a quick removal
if there are any areas of composites still on the tooth surface I recommend using a slow speed round
bur to gently remove the excess I try in each veneer individually to verify they seat properly
and the margins are flush to the teeth with number 7 and 10 I checked the distal contacts first to
ensure that the contacts are not interfering with the seating of these restorations with multiple
unit cases it's best to check the contacts against the adjacent non prepared teeth first and adjust
these as needed then check the contacts of your restorations two at a time we want to
verify that the margins and the restorations when seated together match the flush nests as when we
checked them individually if they're off in any way then there is likely a heavy contact somewhere
to prepare the veneers for cementation we apply IVA clean to the internal surfaces for 20 seconds
and rinse and dry them out afterwards we apply a coat of Mana Bond Plus which contains the required
silane coupling agent to allow the resin cement to adhere to the ceramic surface for the preps
I use a total edge technique to maximize the bond of these veneers I first protect the canines with
a clear mylar strip and then with 37 percent phosphoric acid on all those preps for about
20 seconds next I apply a thin layer of glue ma desensitizing agent to all of the preps and
allow that to sit for at least a minute and then aspirate any excess I follow that with avec lars
excite FD SC adhesive the F indicates that it is a fluoride releasing adhesive and DSC is dual cure
single composite I applied the bonding agent along the margins and with pressure ensure I scrub the
material into the dentin really well for at least 20 seconds and this allows the resin monomers to
effectively infiltrate the collagen matrix since the adhesive is a dual cure after air thinning
to remove the solvents I go ahead and see 8 & 9 using very linked aesthetic resin cement I really
like using this cement for aesthetic situations because it is available in five different shades
that can increase or decrease the value as needed there are try and paste that correspond to each of
the shades so you can determine which shade will work best for each case we went with the neutral
for these veneers as we didn't need to alter the final shade with the cement once the veneers are
fully seated we tack cure along the gingival margins to accelerate the cement to a gel state
to aid with the removal after most of the cement is removed along the gingival margins and lingual
we polymerize these areas more so they can help hold the veneers in place during the interproximal
removal which is usually the most challenging area we repeat this same process on the laterals
the patient was extremely happy with the final results as the Obsidian lithium silicate veneers
provided a much more natural appearance over the old composite restorations and blended in very
well with the rest of his natural dentition the material offers three hundred and eighty-five mega
Pascal's of flexural strength so obsidian offers a great combination of beauty and durability
and is my go-to material for aesthetically demanding cases on behalf of everyone here
at the lab thank you for watching chairside live and we'll see you back here next time
you