Saturday, July 21, 2012

Episode 379/500: Dental Gadget

I've had this video up on Youtube for a week and have had a few interesting suggestions as to what exactly this gadget does.


My mother and father owned a business in a really old building - they rented office space in there - and - as a young kid, I'd be all over the place hiding and adventuring with my younger brother.



The basement was this incredible pirate ship that was filled with old gadgets from bygone eras.  I'd always try to figure out what function/utility they were designed for.  Fast forward my entire life and here I am again - rifling through drawers in the building and come across this funny thing.


Dr. In.Saini has already left to find a cure for alien gingivitis (or something of similar usefulness) - so - I have to demo this thing on myself.  But, before that - 


What do you think it's for?


Cheers


Ashley











Thursday, July 19, 2012

Episode 378/500: Partial Dentures of Choice

So few things in life are straightforward - and that includes partial dentures.  I thought the choice was either a provisional acrylic partial (the ones no patient wears), or a cast partial (the ones no patient wears).  So - 2 choices and patients typically can't stand them for anything other than esthetics....hmm.


Recently, I've started seeing more residents delivering a heck of a lot more of flexible partial dentures - ie - valplast. Perhaps once it was the "garbage method" of treating partial edentulism (maybe it still is)....but...more often than not, patients love these prostheses. Their gingival health is in excellent shape, no rest seats into the adjacent teeth, superb comfort and great esthetics.




Valplast, partial denture, flexible denture

There is very little evidence to support one way or another. This appears to be an opinion/experience driven donkey cart.

What's your choice?  Cast or Flexible.

Place in comments.

Cheers




Wednesday, July 18, 2012

Episode 377/500: Digital Calipers

I was "raised" in dental school to use a Boley Gauge to make "accurate" measurements.  We sharpened the ends so we were able to slide them interproximal and get exact dimensions.  I learned how to line up one line with another to obtain an exact measurement.
Fast forward 10 years - I can't remember how to read the gauge!  Yikes.  I still haven't relearned.  Is that sad?  I'm not sure.  I learned how to type on typewriters....haven't seen one of those in a heck of a long time....haven't looked back either.


Dr. InSaini lent me his digital calipers during the residency - he had a research project that involved measuring mandibular incisors.  Wow - what a difference from the classic methods of measuring teeth - be it a boley gauge, a ruler, a compass, etc.  I turn it on, zero, and bam.  It's done.  No, it's not autoclavable - but - much of the measuring usually is at the lab bench/desk before setting sails intraorally.

Thanks Bob.




Cheers


Ashley






Monday, July 16, 2012

Episode 376/500: Locator Pickup Complete Denture


Ok, imagine the scene.  I have some red rope wax in my hands and I'm trying to fiddle with it intraorally - trying to provide some "blockout" relief to the 4mm of threads that are exposed on this implant.

If you've ever tried to place rope wax intraorally - it doesn't work.




I mulled over a few blockout options w/ Dr. K....... blue mousse, another type of wax, horse hair (just kidding)...and he said he used teflon tape before.

As if.

Oh yeah....and....it worked.


So, a few years back, when denture set #9 was fabricated (ok, maybe I"m off a few sets), the clinician forgot to blockout the threads on the implant - and - locked the denture in.  It's extremely easy to forget to blockout those threads.  I"ve been lucky so far.  It took them 3-4 hours to try to weasel that denture off the implant - without sectioning (cutting) the denture in 2-4 pieces.  I'm 99.3% sure that's where those ding marks in the implant came from.


Phew.  I was spared from the "locked in denture goddess".



Using the teflon tape was much easier than wax, cheaper and less messy than bluemousse, and easier to handle than horse hair. 

Thanks Dr. K.  I will miss you. :)  You've been a great mentor in the realm of prosthodontics and funny jokes.

..and as your door says now, "Do not mistake my kindness for weakness".  100% true.







Thursday, July 12, 2012

Episode 375/500: Implant Abutment Material Selection Tips




This tip sheet came from the regional laboratory and provides a couple of hints regarding implant abutment MATERIAL selection.



There are 3 basic materials from which custom implant abutments are constructed: titanium, zirconia, and Type III gold alloy. Titanium and zirconia abutments are designed using a computer program and milled. Titanium is a gray color (some companies offer nitride coating as an option, which is a gold color) and zirconia is available in several shades  of  “white”.    


Type  III  gold  abutments  are  waxed  by  hand  on  a  machined  UCLA  alloy  metal  platform,  then  in-­ vested and cast. Naturally, they are a yellow gold color


zirconium abutment, implant abutment, implant margin, crown margin, moulage, dental implant, procera

In general, cast gold UCLA abutments allow for greater flexibility in design. For example, when the implant is not placed very deep and the platform is only slightly subgingival or is equigingival, your first thought may be to use a zirconia abutment because any part of the abutment that is visible will be tooth-colored. 


However, there are limits to the angles titanium and zirconia can be milled. With titanium and zirconia, the body of the abutment cannot be milled more than 30° off-axis from the body of the implant. At the margin, zirconia cannot be milled more than 40° from the long axis of the implant. 


zirconium abutment, implant abutment, implant margin, crown margin, moulage, dental implant, procera


Whereas gold can be cast into any form, including an almost 90° angle from the long axis of the im- plant. This allows flexibility in designing abutments for implants that were not placed in ideal positions, such as offset to the lingual or plat- forms that are not deep enough.


Milled abutment designs are limited by the capabilities of the milling machine. There are certain angles and dimensions that are impossible to achieve. Zirconia must also have a certain thickness to resist fracture. If it is milled too thin, especially at the margin, it will fracture. It can even fracture under the hydrostatic pressure of cementing a crown. 


Cast gold abutments can be shaped freehand and overcome many of the limitations of milling. There is also a minimum thickness for gold (for strength), but it is easier to manipulate the contours and overcome shortcomings in gold than with milled abutments. The yellow color of Type  III  gold  is  also  more  esthetic  and  ‘warm’  under  thin  biotype  tissues   than the dull gray color of titanium. 


Even some all-ceramic restorations, such as Lava, look good over a Type III gold abutment due to the opaqueness of the zirconia coping blocking out the gold color. 

Wednesday, July 11, 2012

Episode 374/500: Cracked Tooth Transillumination

I'm slowing editing the 4gb of video that I compiled while putting together a complex amalgam video.  I was able to capture a huge portion of it under the dental operating microscope.  We're fortunate to have several endodontic microscopes for use during endo - I'd have to say that a microscope is approaching the standard of care for endodontics.....but in all honesty - who am I?


So, imagine me running around the building asking for people's opinions regarding placement of a complex amalgam.  "What would you do here? What retentive features do you regularly use?....on and on.....


I slither into the endodontist's office and ask his opinion.  He mentioned to take a look to see if there was a fracture.  I was like...."hmmm".  None of the other folks including me even thought about evaluating perioperatively (during the preparation) for fractures by using a light - we just - assumed there would be a fracture and included it/them into the preparation/restoration design. Interesting...


tooth fracture, tooth crack, fractured tooth, transillumination,cracked tooth
Transillumination to find a horizontal crack in an
all porcelain crown. I'm using the fibre optic
handpiece light

tooth fracture, tooth crack, fractured tooth, transillumination,cracked tooth
The crack can't be seen with the flash on


tooth fracture, tooth crack, fractured tooth, transillumination,cracked tooth
Turn the flash off on the camera and voila - you viewers can
see the crack and as well, I haven't set my camera well enough
to operate in low light minus flash.



There are a number of gadgets for transillumination - from using a handpiece light (the photos above show me using a handpiece coupler to highlight a fracture in an all ceramic crown), to a purpose built light - to a $4.99 bore light.


tooth fracture, tooth crack, fractured tooth, transillumination,cracked tooth
$4.99 bore light does the trick


Finding a fracture is one thing - now what to do about that fracture is an other.  
A cardinal rule that I've been taught is not to follow a crack, but, preoperatively evaluate for signs and symptoms for cracked tooth - then - discuss treatment options.  It's not always that straightforward, and there is little scientific evidence to argue the best treatment in a case like this.  Does this tooth require more than a cuspal coverage amalgam?  Good question. I honestly still have not found the answer - and - that's one answer that I wanted to find out.

Questions to ask yourself:
1.  Preoperative signs/symptoms
2.  What is the occlusion - is there a plunging cusp, parafunctional habits, patient age, tooth slooth
3.  Postoperative signs/symptoms - no change, better, worse

Cheers

Ashley



Sunday, July 8, 2012

Episode 373/500: USS Midway Aircraft Carrier

Since we were visiting San Diego, I figured I'd take the boys (minus mom) to go and see the USS Midway Aircraft Carrier.  Sure enough, the flight deck was exciting, but further down into the ship, their attention span waned.  I almost didn't even make it to the sacred dental section - but - we found it. After both boys slipped down some stairs (only small bruises), and complaints of the smells, I was able to capture a small segment of video.  Spiderman was an attention grabber!

USS Miidway, dental clinic, navy, naval dental clinic, spiderman
All smiles before entering the USS Midway.





The dental clinic was very similar to the USS Lexington's dental clinic -  I visited it with my brother and parents Jan 2012.  I had a little more time to capture some decent video as the boys were at their uncle's wedding down under.


Friday, July 6, 2012

Episode 372/500: Implant Success

Situation:  Fending off sleep.  Our 3 boys are FINALLY dreaming in our San Diego hotel room and I've been thinking of this post off and on throughout the day.  We've spent the entire day playing at a number of children learning places, while mom plays business person at a conference.


 I thought I'd take some time and post a question regarding this past week's treatment - and soon - the tip that Dr. K gave me on how to solve a potential issue when restoring the case below.


We've been fabricating an implant supported maxillary fixed overdenture for this patient, and we're just about complete - I"m 1/2 way through the clinical insertion stage - it's a slow process (especially if you are a newbie......me)


But this implant photograph is not of her maxillary arch - it's her mandibular arch.  Let's review her history.


dental implant, denture, locator, complete denture, removable denture, prosthodontics



CC: 55 yo female presents w/ a chief complaint of "my upper denture continually breaks and the locator nylon inserts always wear out"
History of present illness:
    Patient was born with a cleft palate and has undergone several surgical procedures as a child to close the cleft.  She became edentulous 30 years previously.
   6 Branemark implants placed in the maxilla and mandible 25 years ago 
Maxilla: 2 failed within a few years, and 1 is unrestorable due to location
Mandible: 2 failed within a few years

So, we elected to fabricate a fixed overdenture for her maxilla - more on that later.  The real question is about this image:

Mandibular right implant:

dental implant, denture, locator, complete denture, removable denture, prosthodontics
Whoa. Doesn't look like that from the occlusal shot! That's a
locator abutment/attachment

dental implant, denture, locator, complete denture, removable denture, prosthodontics
This one has taken a beating over the past 25 years.

Is that a success or failure?

The textbooks (and websites) always show the easy cheesy, nice looking implants - rarely real life.  In the course of practice, you come across many crazy looking things and without a support network to go to, it's difficult to make a solid decision about almost anything!
Let's see.  Implant success has been classically described by Albrektsson (among many other classifications) as:

No pain
No mobility
No peri-implant radiolucency
No progressive marginal bone loss

I apologize for the lack of radiographs (there is still approximately 10-12mm of implant in bone), however, there is no mobility, no pain, and no peri-implant radiolucency.  There has been progressive marginal bone loss - but - she was a super smoker and it's still in after 25 years. 

Ask the patient if she wants to keep it? Darn right she wants to keep it.  It has been restored with some sort of denture retentive abutment for the past 20 years and don't even think about removing it, or, not "attaching it" with a locator attachment in the denture.  I'm not sure you can sleep this implant easily.

So, begs the question - what would you do?  I'm not sure there is a right answer. We're going to keep it in function and keep the locator.  

Bonus - what do you think has caused the number of bur marks in the threads?


Tuesday, July 3, 2012

Episode 371/500: Experience Needed - Amalgam Retention




A few viewers asked for some tips on complex amalgam placement.  I"ve been hesitant to discuss amalgam, (it's controversial...), but, I've been given some great tips over the years and wanted to share them. I ran around the building a few times as well to ask others what tips they have - some really nice ones were described.

Before we put together the entire series, I wanted to ask viewers their opinions on what additional retentive features they would add.  I learned a few tips just from shooting the video from other residents and mentors.


I was also fortunate enough to capture Dr. InSaini on video discussing why I wasn't able to detect the mesial decay (see photo below) on the radiograph.

Your help is appreciated!


Kind regards,


Ashley
dental radiograph, amalgam, filling, tooth, xray, periapical
Preop radiograph




filling, amalgam, restoration, preparation, decay, cavity, molar, mandibular molar
The mandibular molar on the far right is the tooth to be prepared





filling, amalgam, restoration, preparation, decay, cavity, molar, mandibular molar
Great view of the caries on the distal
An incipient lesion at its finest

.



filling, amalgam, restoration, preparation, decay, cavity, molar, mandibular molar
Heavily stained pulpal floor.
filling, amalgam, restoration, preparation, decay, cavity, molar, mandibular molar
Mesial Caries -- Take another look at the radiograph and
see if you can see caries.
filling, amalgam, restoration, preparation, decay, cavity, molar, mandibular molar
What retentive elements would you add to this preparation?