Category Archives: Crown and Bridge

I Love Gold Crowns + Photos

I think one of the fun things to do in dental school is making a gold crown.  I’ll tell you why – as a student you have the control!  After the prep and impression are taken you can decide when to pour up the models, mount them, wax the tooth and cast it.  There are some steps in between to get signed off by faculty, but ultimately the control is in the students hands.  There is no lab slip, no lab time, and no chance for a potential mess up by the lab.  I have recently been working on a gold crown for #18.  Everything has gone very smooth and I am pleased with the outcome.  When a gold crown is treatment planned you will want to take the following steps (this is mostly for Temple Dental students).

1.  The patient has to pay AT LEAST half of the cost of the crown.  At Temple we charge $350.00 which is a steal!  If the patient can pay in full then get them to pay up front, it makes life easier.

2. After they paid, go and get an approval form and fill it out.  Take the approval form to a clinical coordinator so they can stamp it.  After it is stamped, go through the checklist on the form and make sure you have everything done in the chart.  You have to make sure the recall is done, signatures are up to date, etc.

3. Put the form in the chart and submit it to the AEGD window for approval.  This takes 24 hours.  After this time period the chart can be found back in central records.  Go pick the chart up and see if your plan is approved.

4. If you are approved you can get your patient in and start treatment. If not, fix what you are missing and resubmit your form.

Here is the crown I have been working on for the last few weeks (total of 3 appointments for a parapost and composite buildup and prep and impression).  I plan to cement it within the next week.

gold crown on die in articulator

shiny!

gold crown on die in articulator

gold crown on die in articulator

gold crown on die in articulator

gold crown on die in articulator

gold crown on die margins

gold crown on die

Othe reasons to like gold crowns:

Typically there are less appointments because there is not a coping try-in step before porcelain.  The margins always come out better (at least for me).  Gold is simply awesome to look at.

Hope you enjoy the case!

P.S.  I tried to get the bridge, but the patient just wanted to get the crown done. FYI!

Porcelain Fused to Metal Crowns & Photos

***Update (Feb 28, 2009): Porcelain Fused to Metal Crown Part II
Today I had the goal of fast tracking someone through the fixed clinic.  The graduate periodontology clinic picked this patient up right when we were done with his comprehensive cleaning and stalled my treatment by TWO MONTHS!  The service they were trying to treatment plan him for was needed but he is on government aid and they would never approve the treatment grad perio wanted to do.  Anyway, to avoid becoming too bitter in this post, lets just say that I was motivated to get this patients treatment done as quickly as possible so no more delays can get in the way.  His treatment plan is as follows:

1) Extract all remaining maxillary molars
2) Prophy, Flouride, OHI
3) PFM noble metal #22, 23
4) Mandibular RPD, Maxillary FPD
Here is the FMX series:
modified FMX [8]

The extractions were completed, the prophy and scaling was completed and today we started on both of his crowns. I picked a good row instructor in the fixed department so I could get as much as possible done today.  One thing I like about Temple – and I am not sure if it is like this at other schools – if you can get the treatment done in the allotted time then you are given the green flag to do it.  So here are the crown preps I was able to do today.  Remember that everything went smoothly during this appointment and so far this is not common for me. I had some luck on my side today and was happy with the results.  Here is a before shot:

before

I took a pre-impression with impergum (hence the purple on the lips).

Here are my preps, a few from the facial, occlusal and a shot with packed cord:
preps occlusal view

preps occlusal view

facial view of preps

occlusal view of pcked cord

After the preps were done I made the temporaries using Integrity. I had never used Integrity before and I really liked it. I got it from a vendor who got my name from a Temple Dental graduate. Thanks Dr. Beth! The integrity was fairly easy to work with, set quickly, didn’t shrink, and the color (A2) was a great match. The margins were easy to read and easy to trim. Check out the final product:

provisional made

I was able to do all this and get my final impression in one clinic session. I was pretty amazed with how smoothly everything went. Two preps, two provisionals, an impression of the final preps and some photographs all in 3 hours. I know that is nowhere near private practice status – but remember this is dental school and these were my 3rd and 4th crowns (if you remember I finished a bridge not too long ago).

Dental Three Unit Gold Bridge

I picked up a patient through our preventive dentistry clinic where we do a couple of rotations through each semester. These patients are recall patients who have had dental work done at Temple and come in periodically to maintain their oral health. If the ‘prevdent’ patient happens to have another dental need that needs to be addressed besides a prophy, such as the onset of a new carious lesion, then the student on rotation can add them to their patient pool and address the problem. To make a long story short I picked up a patient from ‘prevdent’ and after addressing his initial problem a new problem was introduced to me.

He called me complaining of the PFM on tooth #21 that had broken off at the gum line. The tooth had been endodontically treated and was brittle. The whole coronal portion of the tooth including a prefabricated post had broken off with the crown. We made an appointment and after reviewing the case clinically and radiographically discussed various treatment plans. The patient decided that he wanted a gold bridge.

The first step was extraction of the retained root of #21. The extraction went smoothly and was allowed to heal for two weeks before our next appointment. The bridge was planned to span from #19 to #22. #19 had mesially drifted into the position of #20 so the bridge would be three units. #19 already had a gold crown so it had to be removed. This tooth was also treated endodontically and a portion of the coronal part of the tooth and a parapost broke off with removal of the crown. The parapost that broke off was not cemented deep enough into the root so a new parapost was placed after increasing the length of the canal with a parapost drill. The post was cemented in the distal canal and two pins were placed in the mesial buccal and mesial lingual portion of the crown. The crown was built up with composite.

The teeth were prepped and provisionalized. Impressions were taken a week later and poured up in jade stone and mounted to the articulator. The wax up began. Here are some photos:

Lingual view
bridge wax up lingual view

Buccal view
bridge wax up

In occlusion
bridge wax up

Contrast
gold bridge wax up

I cast the whole thing in one large ring in two pieces. The distal abutment was separate from the mesial abutment and the pontic. It came out beautiful. The next visit was a try in and solder. The bridge was soldered and temporarily cemented in for two weeks. (Normally you wait one week and then check the gingiva for inflamation and make sure the occlusion was good – but Thanksgiving got in the way) After two weeks the gingiva looked great and the occlusion was fine. The crown was removed (with quite a bit of force from an occlusal hammer) and polished to a shining glow. I thought it looked fantastic. Judge for yourself:

Final Cementation
gold bridge final cementation

Overall I was very pleased with the way the bridge turned out. I am also grateful for my patient who came in for all the dental school appointments needed to make this possible. It took about 5 appointments (including tx plan and extraction) to get the job done.
I am open to comments and suggestions, please share in the comments below.

Gold Crown Videos

It helps to see the process before you do it for the first time. Make sure to add BORAX (I didn’t add any in the video and it still turned out, but better safe than sorry)

Enjoy!

Gold Crown Part I

Gold Crown Part II

Restorative III projects

I haven’t been as diligent in picture taking this year. Partly due to a broken camera for the first month and partly due to time crunches in lab. When you are trying to pass off crown preps, wax-ups, provisionals, and get castings done for a porcelain fused to metal casting the last thing to think about is taking pictures. HOWEVER, I have been able to take a few pictures of some random things we are doing.
Last year in Restorative II we had a gold crown due as our final project. The final project in Restorative III is a porcelain fused to metal (PFM) crown. In short the steps of the PFM crown are similar to the gold crown. You do the crown preparation, make a custom tray, take an impression, pour up jade stone, drill pindex holes, form the base, mount on articulator, cut the jade stone, and then wax up the full crown. This is where it gets different from a gold crown.

Porcelain requires a certain thickness for strength, so instead of casting the whole wax crown you must cut back some of the crown so you can add porcelain to it AFTER it has been cast. The tooth is also prepared differently so after you remove some wax from the crown there is still enough wax left to make a strong enough metal base. The metals minimal thickness is .5mm while the minimum porcelain thickness is 1mm. This means that anywhere on the tooth where there is going to be porcelain you want to reduce it by 1.5-2mm.

Here is a shot of tooth #8, upper left central incisor with a temporary on it. If you look to the right you will see a chunk of acrylic on tooth #5 an upper 1st premolar. We are doing the porcelain on the opposite premolar, #12.

#8 temporary

The next picture is of tooth #12 after the preparation, provisional, impression, jade stone, pindex, and articulator mount. It is ready to be waxed up. We wax up the tooth to look like the full tooth and then we remove wax in certain areas of the tooth (facial, occlusal, coronal 1/3 of the lingual, and the mesial and distal contact areas. Porcelain also has to meet metal at a 90 degree butt joint angle. The cut back also has specific dimensions. Here is the mounted articulator with #12:

articulator first premolar pindex

I have made the wax cut back and sent it off for investing. It turned out nicely. I will be taking picture as we progress with this project. The next steps will be to add various layers of porcelain to the casting. There is an opaque layer which covers the color of the dark metal casting, a dentin layer to add natural tooth color and then a translucent layer to look like enamel. The steps include time in the oven at very hot temperatures after layers are added to bake the porcelain on. More to come on these details.

We have also been practicing doing PFM preps on various other teeth in the mouth. It is hard to believe that we will be doing this on patients in about 22 weeks. Here are some more pictures:

PFM cown preps and temporaries

Temple Dental Lockers

Pathology Lecture:

PICT0102

More information on PFM’s (I did a google search so you can browse these at your leisure, most are randome websites)

http://www.pjsdental.com/porcelain_to_metal.htm

http://www.smartooth.com/PFM%20Preparation.htm (Has some good preparation shapes and critiques)

Making a Custom Tray

The need for a custom tray arises for a couple of reasons: The impression material is typically an elastomeric compound and these types of materials are most accurate when they have a uniform thickness. The custom tray allows the material to have a uniform thickness. Stock trays do not fit the mouth as well because of their universality. This is important for the pouring of models used later in the process and it is important when making a fixed partial denture. When using a custom tray a more accurate abutment distance is achieved. Before I say that it is detrimental for anyone to use a stock tray the differences in bulk of material were les than 1mm and the differences in abutment differences were 100 micrometers or less. Even so accuracy in dentistry is an important factor. I am not sure how often custom trays are used in the everyday practice of dentistry, but it is better to be exposed to everything than just a little. So this is how to make a custom tray:

Before any one gets their hopes up I did not have my camera when I made the custom tray so few pictures are available. The process is pretty simple though.  Here are the steps: Continue reading

Gold Crown

UPDATE (11/14/2007) : Added videos of the Gold Casting Process.

Our final project in Restorative II is to make a gold crown from start to finish. Looking at all the steps required to make a gold crown can give you an ulcer. In total it took about 2-3 weeks of work. When I say 2-3 weeks this doesn’t mean 2-3 weeks of solid work. We had a couple of practicals to do in this time along with daily work and physiology every morning. There are some things about making a crown that SEEM like they are a pain, but I chalk this up to being inexperienced. I have written about the learning curve in dental school before and this project is no different. At first it can be uncomfortable. With experiance it become second nature and then it becomes fun. One important thing before I discuss the process: You have to be anal over the quality of your work, because if that gold crown comes out and doesn’t fit your tooth…you’re STARTING OVER!

So to ease the burden of some of the new dental students or to those of you who have not done this yet here are the things we have been doing. Those of you who have done this before, then please share your tips!
We made a crown preparation of tooth #3 (maxillary first molar). After the preparation is done (MAKE SURE IT IS EXCELLENT) you make a temporary for it and you also take an impression using a custom tray. The custom tray is made out of a material called Triad. It is made on a stone model of your typodont. Here is what it looks like: Continue reading

Iraq SGT Shot in Face, Saved by Incisor

1) We got this in our dental school email today and even though it is a year old I had nPhoto courtesy of Flickr user nagillumever seen it and thought it was a very cool story. Cliffs notes: A SGT rounded the corner in a house being raided and came face to face with a 9mm handgun. The gun was fired at point blank range right into the upper lip of the SGT…

…well if you want to read more check out the story at Snopes.

2) I have also been introduced to another website that you can bookmark for further reading. It is called The Endo Blog by Dr. Jason Hales. It is new, so be sure to bookmark it or add it to your reader and welcome him to the world of blogging!

3) Also coming soon is the long write up of my gold crown. I finished it today! I have some other things to do before our projects are due on Thursday like finishing my provisional for #3 (the tooth we did the gold crown on) and finishing my three unit bridge. Just some minor adjustments like polish and occlusion. Here is an excerpt from my gold crown article:

“The polishing steps for a gold crown entail about 7 jaw clenching steps from start to finish. I was biting down so hard while I polished that I went through 3 acrylic mouth guards. After so much work with impressions, models, waxing, investing, and casting you don’t want to screw up the crown while polishing it. The sweat equity, tears, and blood devoted to this project would have been enough to kill an undergraduate student. Why do you think they make AADSAS so hard? It weeds out the weak and the timid, the faint of heart, and those with high blood pressure. Applicants like that couldn’t handle this type of stress. If you fail this crown you have to repeat the year. Needless to say the tension in the pre-clinic was thick. After finishing the first 6 steps I’ll admit I was disappointed. My crown looked as dull as a slab of granite. I felt like someone had painted it gray and then stabbed a knife into my back. The crown and the knife sat there, festering. I was a beaten man.
I had no one to reach out to, my classmates had their own crowns to worry about, my teacher had that glossed over look in his eyes that said “If another student comes up here for advice I will go postal�, and I couldn’t see an upperclassman anywhere. I am sure the upperclassman had enough problems anyway. They didn’t want to deal with a mere ‘D1′. What did I know anyway? After all, I wear scrub pants and don’t even work on real patients. I would be scoffed at. With no one to turn to I looked at my work area and saw Red Rouge. It seemed to look at me longingly.

“PLEASE! Pick me up and rub me on your gold crown with your low speed hand piece and a polishing wheel!�

Caught up in the moment I replied, “Okay�, as my classmates glanced at me clearly annoyed that I was talking to myself again.

I picked up the Rouge and started to rub it into my polishing wheel softly but with great purpose, like I had done it before. It felt right. The quiet, slow ‘whirrrrrr’ of my hand piece drowned out the moans and wailings of the classroom. I was alone. I began to gain confidence in the skills I had learned over the past 6 months. The feeling of complete and utter belonging overwhelmed me, and a tear fled from my eye and floated onto my polishing brush as if to calm the raging sea of red that had enveloped the polishing wheel. I lifted the hand piece to my gold crown, which was seated firmly to my stone die. The red bristles began to dance off the gold like sparks in the wind. Everything was moving in slow motion now. Some of my classmates looked up to watch the magnificence that was unfolding before their eyes like spring blossoms. I wouldn’t be exaggerating if I were to say I saw tears of wonderment well up in their eyes. The dull gold, which had once been a nagging wound in my back, slowly subsided as the gold began to sparkle like the salmon of Capistrano. As I looked at my reflection in the gold crown I no longer saw a beaten man. I saw the chiseled face of a student who had been whittled and pruned by instructors. It was this moment that I had realized my true calling as a dentist. I have Red Rouge to thank for it.

Okay, well maybe that was a little overkill. I had fun writing it and there are some truths to it. The crown does look ugly until you add red rouge to it. It wasn’t as difficult as this excerpt claims to be, but there IS truth to every joke. DID ANYONE CATCH THE DUMB AND DUMBER PHRASE I USED? It also feels very good to almost be done with a class that has been going for 6 months. That is half a year (duh), but it is long. Our instructors are great. Dr. Boberick is also an excellent instructor in my opinion, although today he told us that he has been called every four letter word in the book. I am sure all of us have been. Here is my four letter word for this class: It has been pure ‘gold’. Stay tuned for the real article.

Making a Three Unit Bridge Using a Vacuform

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.

I Crown Prep Thee ‘Sir Provisional’

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!