Category Archives: Acrylic

Reprocil is my new best friend

Posted on May 26, 2007 by CheerioKing| Leave a comment

After doing block carving and vacuform plastic matrix acrylic for a while it has been nice using this material we have been introduced to called reprosil. It comes in many forms, the pictures here is the putty stuff, there is also light, medium and heavy bodied stuff that allows for greater detail, etc. We should be using it soon. This post is short, but I want to illustrate the difference it makes.

The material comes in two buckets. You mix equal parts from both buckets and get a Play-doh type of material. You squish it onto the teeth and let it set. After a few minutes it has turned into a stiff rubbery type of material. Here are some pictures:

reprocil

reprocil

When it sets you prepare the teeth like shown in previous articles and then you use this reprocil as a mold for the original tooth anatomy. Lets see if I can clarify this for you:

  1. Reprosil impression
  2. Prepare teeth
  3. Place acrylic into the reprosil mold and squish it onto prepared teeth
  4. The teeth that come out look like the old teeth and fit onto the prepared teeth.
  5. Time saved: 30 minutes

I have been told that not many dentists use this, and in fact you will rarely use it in the clinic on patients. There are even easier methods than this. Still, it is good to get your hands on everything possible. Here is the difference between the two teeth. Notice the teeth in the typodont are the ones I carved that you thought looked so sweet. i admit they are not my best performance, but this WAS my first one ever. Compare it to the reprosil model.
Reprocil vs vacuform
It is good that we are taught how to carve out of acrylic because sometimes you will be faced with a patient that comes into your office with a broken tooth and you will not have original tooth structure to go by. You will have to carve one and make sure it is of high quality to be used as a temporary. Many students at Temple in the clinics still block carve their temporary crowns.

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Posted in Acrylic, Restorative Dentistry

Finishing the Three Unit Bridge

Posted on May 26, 2007 by CheerioKing| Leave a comment

Now that I have made the plastic form I can start to make the three unit bridge. Vaseline the teeth you have prepared so the acrylic doesn’t stick to them. You don’t use vaseline in a patient, their saliva lubricates everything enough so the acrylic doesn’t stick. Mix the liquid monomer with the polymer sand and pour it into the plastic matrix. Try not to get any air bubbles while pouring. If you do then you can always fill them in later, but it takes extra time.

acrylic three unit bridge

This photo shows what the acrylic looks like after it has been placed on the teeth and the plastic matrix has been removed. Right now it is pretty rubbery. Here are some more shots:

Acrylic three unit bridge

Here is the temporary removed from the mouth. From here it is placed in water or off to the side until it is fully dried.

temporary acrylic bridge

As you can tell there is not very much detail, however it is better than a basic block carving of acrylic. There is still much work to do. The next picture shows the underside of the temporary. Acrylic shrinks a lot so this probably won’t fit on the teeth anymore. A re-line has to be done. A re-line is the process of carving out the middle of these teeth, pouring more acrylic into the hole and then re-seating the bridge back onto the crown preparations. Here is the underside of the crown. The two teeth that fit over the existing prepared teeth are called abutments, the middle tooth which will be ‘floating’ is called the pontic. Ideally the pontic will be in contact with the gingiva to stimulate the tissue on chewing and to keep the bone from resorbing.
Bottom of Acrylic Temporary

After some more carving of the teeth, they start to take form. There are various diamond burs, carbide burs and discs used to get the final results. Here are some shots of the work in progress.

Placement after refinement

final product

This project took me about 10-15 hours. In a couple of weeks we have a practical where we have to do this in three hours. I have noticed in dental school the learning curve is very low at first and it can be frustrating while trying to nail the skills. But once you reach a certain point that curve shoots up exponentially. Before you get any ideas of becoming cocky, let me assure you that when you do reach this exponential growth of skill, you will most certainly be taught a new procedure that leaves you back at the low point in the curve. Let’s hope I can get to the high point of the curve before the practical. Here is my final product:

underneath

bridge

bridge

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Posted in Acrylic, Classes, Restorative Dentistry

The Simpsons Visit the Dentist

Posted on May 23, 2007 by CheerioKing| Leave a comment

A classmate of mine sent these two videos out in an e-mail. I have some other articles in progress, but I need to wait until next month when I can add photos to my Flickr account. A pro account is needed to be able to upload an unlimited amount of pictures but the cost is 25 dollars too much. What I am trying to say is that unless you want to donate 25 dollars you will have to wait until next month to get anything of true value. For now these videos should suffice!

Video 1

Video 2

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Posted in Acrylic, Humor

I Crown Prep Thee ‘Sir Provisional’

Posted on May 5, 2007 by CheerioKing| Leave a comment

Courtesy of Flickr: snake3yesI felt like I needed a more interesting title than Crown and Acrylic…that is so boring. Most people will find it boring reading about a random student in a random city practicing dentistry on plastic teeth and bragging about it on the internet…it doesn’t quite shout out ‘READ ME’. I decided to spunk it up (yes this is my idea of going wild :)

Our recent projects have included continuing our crown preparations and making acrylic provisionals for the crown preps. I have taken many photos this time as I know this is what most people like. We had to do four teeth OUTSIDE of the head out on the table tops. This was to help us get a feel for what we were doing. Here are the steps, and if anyone has any tips or hints or somthing they like that makes a crown prep easier (like bur selection) please let everyone know by using the comments section.

Step 1: Break proximal contact with mesial and distal tooth (if it applies) with a 169-170. I like to use the 169L (L denotes ‘long’).
Step2: Occlusal reduction – make depth cuts on the functional cusps first at 1.5mm then reduce. Do the non-functional cusps 2nd. Reduce 1mm. I use a cylinder shaped diamond for this step.
Step 3: Axial reduction (sides of tooth) using depth cuts to .75mm using a torpedo shaped diamond bur. Use this buccally and lingually.
Step 4: Use a diamond flame shaped bur for the proximal of the tooth and reduce .75mm

I have been told that it is possible to do the entire tooth using one bur. This may be true and may not be for the faint of heart. The magic bur I have heard about is the 880 diamond bur. Please let us know what you think.
These steps usually do the trick. Sometimes (more often than not) I have a ‘bad day’ in the clinic and it takes me 3 hours to get a crown looking semi decent. Last Thursday I went home feeling great because I did two in less than 45 minutes and in my opinion they look great…we’ll see what my instructors think.

Enough talk! Here are the pictures!

Here is a mandibular 1st molar prepped with it’s temporary crown next to it.

crown prep and temporary

crown prep and temporary

dental crown prep tooth

dental crown prep tooth

dental crown prep tooth

Here is maxillary 2nd molar in the typodont
dental crown prep tooth

CIMG1372

Temporary

All three of our projects
three preps and two temporary

The fixed portion of Restorative II has been fairly laid back. Not very much reading; a couple of chapters a week or so, but still very informative and very interesting. I think it feels laid back because we don’t have four other classes that we are taking with it. With these projects out of the way we have a couple of more and we are finished. A three unit temporary bridge and a gold crown. Also at the end of the year if you have any failed projects there is a make up day
where you can redo some practicals for a new grade. The new grade is the one you keep…good or bad. If you would like to be “Crown Prepped ‘Sir Provisional’” then send me pictures of your crown preps and or provisionals so they can be showcased right here on DMDstudent.com!

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Posted in Acrylic, Crown and Bridge, Restorative Dentistry

Tips On Using Acrylic to Make Temporaries

Posted on November 2, 2006 by CheerioKing| Leave a comment

No doubt you will be using acrylic during your first semester in dental school. Learning how to use acrylic is fundamental because your competancy in it’s use will be graded in your board examinations (not all board require it though…I think…please enlighten me), but more importantly, your mastering of acrylic will be important for your patients. Many of you will say, well what do you know? You’ve been going to school for two months! You’re right. I am not implying that I have mastered acrylic, but I merely want to share what I have learned that has helped me so far. I would also like to open this discussion up for any suggestions you may have in creating the perfect margin or contact, etc. Feel free to leave a comment below.

TIP #1

Always coat your little pestle with LOTS of vaseline. If your acrylic hardens in here is can be very difficult to remove. Even a thin coat of acrylic in the pestle is hard to remove! Also NEVER use a sharp instrument to remove the acrylic. It will scratch the glass surface and turn your pestle into a crappy bowl. Scratching your pestle will make it hard to mix and remove acrylic. Here is a nice picture of the pestle:

crucible

It has also been mnetioned that you can use a rubber pestle to mix the acrylic in.  The kits at Temple should have a rubber bowl in it.  It is the same size as the glass ones and has a suction cup on the bottom.  If you use this then you don’t have to use vaseline.

TIP #2

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Posted in Acrylic