The sticky relationship between Dentists and Dental Laboratories Mark Jackson, RDT Precision...
-
Upload
lisandro-seely -
Category
Documents
-
view
217 -
download
2
Transcript of The sticky relationship between Dentists and Dental Laboratories Mark Jackson, RDT Precision...
Bound by SiliconeThe sticky relationship between Dentists
and Dental Laboratories
Mark Jackson, RDTPrecision Ceramics Dental Laboratory, DAMASMontclair, CA
According to the FDA, the Dental Laboratory is a Medical Device Manufacturer and subject to FDA Good manufacturing Practices…..
The Dentist and the Dental Lab
But things haven’t always been like this!
During the middle ages and throughout the 19th century, dentistry was not a profession in itself, and often dental procedures were performed by barbers or general physicians.
Barbers usually limited their practice to extracting teeth which alleviated pain and associated chronic tooth infection.
The Dentist evolved from the Barber Shop
At the turn of the century, most dentists were expected to make their own dentures crowns and bridges, but by the 1900’s the dentists realized the economic benefits of finding specialized help.
The Dentist Evolved from the Barber Shop
Professional relations were best summarized in two simple words:
“Yes Doctor.”
The Dental Technician evolved from the “Plaster Monkey”
The “Plaster Monkey” was actually a term of endearment, and the “dental mechanic” became an important member of the dental team, though dentists still kept them closely supervised….and undereducated.
The Dental Technician evolved from the “Plaster Monkey”
Dental Technicians were forbidden to attend lectures and meetings, and in 1963, the NADL and ADA broke off relations.
It was a contentious time.
The Dental Technician evolved from the “Plaster Monkey”
Today’s credentialed technicians have strong backgrounds in material science, dental anatomy and CAD/CAM technology, and in some cases can earn more than a general dentist.
CDT, RDT & MDT Credentials
Despite some professional growing pains, and some sibling rivalry, we share a relationship that is mutually beneficial, financially rewarding and based on a shared respect.
HOWEVER….
But it’s still tenuous….
The dental impression is the key ingredient in our relationship, and can often make or break it. We depend on the quality, consistency and the technical
support provided by our impression material manufacturers.
Our Relationship is held together by a third party
Impressions are the foundation of everything we do.
It all starts with a great impression....
But usually not…..More than 50% of the impressions we receive are substandard, yet only 1-2% will be returned
Proper tray selection
Proper use of tray adhesive
Material properly mixed
Adequate volume of material
Adequate adhesion between
materials
No pressure points or tray pinching
No teeth contacting the tray
Good detail of margin (finish line)
Good detail of prepared teeth
No voids or pulls in the material that
will cause interference
What makes a “Good Impression?”
While this impression displays a number
of problems, it was clearly the improper
tray for this application. Improper tray
selection can cause tray flex and
rebound.
Proper Tray Selection
This tray had no adhesive at all, and
also shows signs of possible tray
distortion. Tray adhesives are
specifically formulated and not
interchangeable.
Proper Use of Tray Adhesive
With modern impression delivery systems,
mixing problems have been all but eliminated,
however glove contamination and chemicals
can inhibit polymerization and setting resulting
in tacky washed out appearance.
Improperly mixed material
Improperly filled impression trays
can result in missed anatomical
features or movement of the
material within the tray borders
Inadequate volume of material
Inadequate adhesion between
different impression materials can be
caused by contamination, exceeding
the working time or improper storage
of material.
Adequate adhesion between materials
This tray was either not positioned
properly, or was the wrong size. When
this happens, the tray can flex and
spring back, distorting the impression,
or in the best case hold the bite open.
Pressure points and tray pinching
Like the previous example of a pressure
point, this tray was either the wrong
size, or improperly positioned, but
instead of a soft tissue compression, we
have tooth-on-tray contact.
Teeth in contact with the tray
Poor gingival retraction and
syringing technique.
Margin discrepancies
Not bleeding the mixing tip or
poor syringing technique has
resulted in air folding or
entrapment
Margin discrepancies
Insufficient retraction or tearing
Margin discrepancies
Improper retraction, possible fluid
or chemical contamination
Margin discrepancies
Improper retraction allowing
blood or saliva to pool around the
prepared tooth. Exceeding
working time.
Margin discrepancies and lack of detail
This impression has voids and pulls
caused by exceeding working time,
moving the tray after seating, or not
enough material. These defects can
interfere with occlusion and mounting
models
Pulls or voids that can cause interference
Communicating with our Dentist clients
Evaluating remakes
Every impression would be a perfect one, that had been inspected by the dentist, and was free of the defects we just discussed, but that is rarely the case….
In a perfect world…..
Most dental laboratories have a profit margin of 10% or less. That means they may have to do as many as 19 units at no profit to pay for a single remake.
Remake evaluation
Every remake is evaluated to determine the nature of the failure. In some cases it is laboratory error or product failure, and sometimes it is doctor error.
Remake evaluation
The easiest way to see if the impression was the problem is to simply insert the new die into the old impression and look for the discrepancy.
Remake evaluation
A common problem is misreading the margin, usually caused by a bad impression, though technician error does happen too.
Remake evaluation
Frankly, the lab takes some blame due to errors in mixing stone, applying surfactant or surface disinfectants, though we try to automate these processes when possible.
Remake evaluation
But in an overwhelming number of cases the problem can be traced back to a bad impression. In some cases we accepted them when we really should have sent them back.
Remake evaluation
There’s never time to do it right
And it’s even less likely there will be time to do it over!
This is where many of us revert back to our primordial roots, avoid confrontation and “do our best” at the doctors instruction
Remake evaluation
At Precision Ceramics……
We take the “passive aggressive”approach…
The “habitual offender” card
PCDL tips for reducing remakes
Carefully inspect your impression before releasing your patient. Any pull, voids, bubbles, unset or sticky material indicates contamination or a mixing problem. This will lead to a remake.
If you use a desensitizing substance on prepared teeth, apply it AFTER taking your
impression. These substances effect impression materials and if used improperly will guarantee a remake.
Retraction cord containing epinephrine, or other material containing epinephrine
will cause deterioration, sticky or unset margins in some impression materials. AGGRESSIVELY rinse and clean the prepared teeth before injecting your wash material.
Materials containing Ferrite sulfate will cause some impression materials to not set
properly, especially in thin areas such as margins. Save yourself a remake; clean and rinse your preps well before taking the impression
If you are using “sideless” triple trays, PLEASE check to see that the patient did not
bite into, or onto the tray. If they did, when we mount the models, the bite will be off, and you will lose precious time adjusting the occlusion and possibly ruining the crown, or sending it back for repairs. A preliminary check could save hundreds of dollars later.
PCDL tips for reducing remakes PLEASE take some time to make sure your temporaries are in occlusion, and that contacts are tight. For long
span bridges, or cosmetic make-overs, consider our lab processed temporaries. Believe it or not, we have seen three and four unit bridge cases with single crown temporaries on the abutments. That’s a great way to guarantee your bridge will NOT fit!
We recommend a two cord technique. A combination of #00 and #2 cords will provide adequate retraction for nice clear exposure of your margins.
For anterior cases, please send an impression of the temporaries, or a diagnostic wax up, so that we can try and
match patient expectations. Photos, shade maps and other tools will ensure a happy patient and a happy doctor. When injecting wash impression around the margins, use a stirring motion and “jiggle” the material constantly to
avoid air bubbles or voids. Never stop and restart an impression. If you don’t think the cartridge has enough material left to completely encircle the prep, use a new cartridge. If the case has loose tissue, of if the prep is very subgingival, use the cartridge tip to push the tissue away as you inject the material to prevent it from laying over onto the margin.
DO NOT use the “touch” technique to determine if your impression is set; use an inexpensive egg timer or other
timing device. The manufacturer has done extensive tests to determine the best setting time and conditions. The material you are touching has been exposed to air, and may set before the was material has, and it is important to have this part intact and accurate. Don’t touch; thime it or you may end up remaking it.
All crown preps should have adequate prep reductions of at least 1.5 mm for both PFM and All Ceramic Crowns.
Note: 7 out of 10 tips are impression related!
Sometimes, we just can’t rehabilitate a doctor on our own..
We call in reinforcements!
Kerr Rep