Monthly Archives: May 2007

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

Making a Three Unit Bridge Using a Vacuform

Posted on May 20, 2007 by CheerioKing| Leave a comment

It’s a vacuform also called vacuumform or vac-u-form. It is a device used to suck down heated plastic onto a figure or mold allowing the plastic to take the shape of the mold. I find it very fun to use and am still building up courage to use it on my face. (sarcasm)
Our typodont comes with a tooth missing in the molar region. This allows us to practice a three unit bridge. First we have to prep the teeth as I have shown in previous posts. Here are some more pictures:

crown preps

crown preps

three unit crown prep

You can see the missing tooth I am talking about. We took an impression of the teeth BEFORE we prepped the molars. This was the first step. We can then take our mold which shows the original teeth (missing tooth too) and wax in another tooth so when we make our vacuform clear plastic matrix it has all three teeth in it. Like so:

preparing stone model for vacu form

preparing stone model for vacu form

The best method to ut this tooth in is to place it in the stone model (don’t wax it in yet) and use the opposing typodont arch and put these two together. This assures that you get the tooth into the right place. Then you can use some wax and drip it on the stone model and secure your tooth in there. You can now use this to make your vacuform mold.

The following picture is the vacuform machine. It has a heating element on top and a vacuum on the bottom. You place the model in between the two like so:

CIMG1488

Then place a plastic square in the appliance:

CIMG1489

Here is a shot of the heating coils looking through the plastic matrix sheet:

CIMG1490

The heating unit is turned on and the plastic starts to get warm and droops down:

Vacuum form machine

Vacu form machine

When the plastic gets hot enough you turn on the vacuum and SLAM the plastic down over the mold. It takes the form of the teeth:

formed to impression

Then all you do is cut out the matrix for the teeth you want to restore, in our case it is teeth 18-20, a three unit bridge. Here are a couple more shots:

matrix on typodont

matrix on typodont

My next post will be the process of restoring these three teeth.

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Posted in Classes, Crown and Bridge, Restorative Dentistry

Welcome to the Real World

Posted on May 15, 2007 by CheerioKing| Leave a comment
The following is an article I asked Linda Zdanowicz from Exceptional Dental Practice Management to write specifically for dental students and what they should look for when preparing to leave dental school. Most of my readers are far from entering the work force, so to make this useful try to keep the following pointers in the back of your mind as you are bombarded with information during dental school.

Have you ever thought about what it’s like for young people getting ready to leave dental school to embark on the career they’ve worked so hard for? I think dental school does a great job of preparing them to work on teeth and if all they had to do was walk into a room full of teeth every day, they’d be just fine. It’s what they don’t learn that can cause discouragement and disillusionment. First of all, it’s tough to start a practice, and very expensive. You don’t want to make mistakes with equipment. I think it would be a great idea to call a few dentists who seem to have updated offices and ask if you can stop by at lunch time or the end of a day and see their equipment and ask questions about what they are happy they bought and what they wish they’d left on the shelf. Keep a list of the pros and cons of everything you think you’d like to have in your office. Be sure that you really want to spend time making your own crowns before you invest in a Cerec machine. They’re expensive and they seem to update with a new model often. I’ve heard good and bad about them so do your homework and consider using a lab at first until you can see some examples of the crowns that result from them.

Don’t be a sucker for every thing the sales reps want to sell you. Ask if they loan you equipment before you actually buy it. My boss tried out one of the new ergonomic chairs and found it wasn’t for him. He was glad to have sampled it rather than bought it.

One thing that new, young dentists seem to struggle with is hiring staff, or if they are associating or buying an existing practice, establishing themselves as a leader with an existing staff. When hiring staff I think it would be smart to have a span of ages with a least one person having some experience in management. I’ve seen a lot of very young dentists hire older, more experienced staff thinking that they will lend them credibility with patients and be helpful in teaching them the ropes. That is sound thinking as long as you have the ability to establish the fact that you are still the boss. Have a good idea of the basic way you want your practice to be and ask your staff to help you make it happen. Write a mission statement, a focus statement and a motto to give your staff a good idea of where you plan to go. If you see that someone wants to take control or treat you in a condescending manner, you need to make it clear immediately that you do not appreciate that and will not tolerate it. If it happens again, it is time to look for someone else. If you allow your staff to push you around, you will never regain leadership of that staff. I’ve walked into situations like that in which a young dentist will look at me as if to say, Help!, and I am amazed at how ineffective they….READ THE REST OF THE ARTICLE

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Posted in Practice Management

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

Crown Preparation Quality and Practical

Posted on May 1, 2007 by CheerioKing| Leave a comment

I had an interesting conversation with a good friend of mine the other day. He works for a large lab and gets to see all sorts of lab work that is sent into the lab from dentists and the work that is done by the lab and sent back out to the dentists. He talked mainly about two dentists who send in work to the lab.

One dentist, we will call him Dr. Malpractice sends in crown preps that look absolutely horrible. Crooked margins, too much tooth structure removed in some places and not enough in other places. There is no rhyme or reason as to what the dentist is trying to do (as far as the lab can tell). This may be slightly exaggerated, but you get the point. On the other hand there is another dentist, we’ll call him Dr. Millionaire, that sends in his work and every single prep is a masterpiece. Crowns are easy to read and the exact amount of tooth structure has been removed which makes the labs job easy.

I wondered what would make the difference between these two dentists. Education? Age? Patient demographics? I know most of the readers of this blog won’t care, so I have decided to talk about my crown practical and relate it to these two dentists. The first crown prep you make will look like Dr. Malpractice’s prep. After a few (maybe 20) tries in the fake mouth you will create a decent looking tooth. Then you get to move onto the maxillary (upper) arch and relearn everything backwards looking in your mirror. Top that off by the fact that you have no suction so your mirror get water on it as soon as you start to drill and you can’t see anything anyway…

I am not trying to scare you, school will strike the fear into your heart all by itself, I am just preparing you mentally. I was reading the blog by Ping about how they had to set dentures in less than 3 hours for one of their practicals. I am sure that must have been quite the experiance.

Last Monday we had to do a crown prep for our practical and I felt like I did alright. It was one of those practicals where you grade your own work and then the instructor grades your work. You aren’t penalized for the grade you give yourself, so I always give myself one check. What I wanted to talk about is the intricacy required to do a proper crown prep. Have you ever sat down and looked at ruler with a mm measurement on it? One mm. Go and look. It is small. A tooth has functional cusps (cusps that fit into the central groove of the opposing arch) and non functional cusps (these do not fit into the opposing arch cusps) and each of these have to be reduced a certain amount. 1.5mm for functional cusps and 1mm for non functional cusps. The best way I have found out to gauge this depth is to make depth cuts into the tooth at intervals so I know how deep I am going (this is also the method taught at Temple).

Next would be axial reduction. Axial reduction is the sides of the teeth. This is reduced by .75 mm and can be difficult when using a large bur. It has been recommended to us as students to get the 850 diamond bur to do crown preps. i don’t exactly know why we just didn’t get this bur in our kit to begin with, but it costs 5.50 cents in our dental school store. (If you want a box, let me know, I get discounts on everything!)

So after all of these technical measurements and drilling (measure twice, cut once!) you should end up with a beautiful crown prep that you would be proud to put into your own mouth and make Dr. Millionaire jealous. While I am not close to making Dr. Millionaire envious of my work (I DO still work on plastic teeth) I would like to think I am better than Dr. Malpractice which, from my friends description, isn’t very hard.

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Posted in Classes, Handpiece, Restorative Dentistry