Amalgam Class I Preparation Tips

[cpayne03]

Hi all,

I'm a D1 and have just been introduced to operative dentisty. As of now, we're working on class I amalgam preps. I've been told a number of different techniques, and I'd just like to hear imput from some of the more experienced dentists on this forum as to what their protocol is/bur selection/electric vs airdriven handpiece usage. If you could, as much detail to your procedure as possible would be awesome.

So far, I've tried using a 330 and a 245 on a high speed airdriven handleice, afterwards using a 957 on an electric handpeice at 10k rpm to smooth the floor. Both times my isthmus was pretty wide and the walls very jagged, but the floor wasn't too aweful. How can I prevent giving away too much width? What are your opinions for finishing the walls making them more smooth?

Any input is greatly appreciated, thank you.

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[Faux]

I'm only a D2 but I'll throw in my two cents until the dentists chime in.

I think you're too inexperienced to use so many burs for one prep, especially with each one increasing in width. You just haven't developed the control or the steady hand yet, which is why you're overextending your isthmus, and your walls are rough. Be sure to change out your burs every 2-3 teeth. The newer the bur, the easier the cut, smoother the walls and floor.

Going from operative 1 to operative 2, I changed to using just 330s. I went from a C to almost an A(89). I think using only a 330 gives you some wiggle room for inexperience, due to the 0.8 width and the 1.6 length. I'm not familiar with RPMs yet, but you can easily smooth our your walls while expanding your isthmus if you're steady/slow enough with a 330 on high speed. At that step, I'm practically using the high speed as a slow speed hand piece. Use your explorer to make sure your floors are horizontal and hills are absent, especially around the groves. Use enamel hatchet to do a final check for walls and floor. Be sure to use the actual cutting edge when switching from buccal to lingual wall.

At the end of the day though, everyone finds their own method to doing things. Listen to advice from different people, experiment and find your own way.

 

[ilyon2012]

Hey there!
I am also a D1 and am in my second semester of operative. Operative for me was very much a struggle! I am still building my handskills and will continue to for years to come, but they did not come easily last semester. I really struggled making passable preps and felt at times that I was never going to catch up. But the "ah-hah" moment did come and it feels so good to feel confident about my work!

As far as your concerns, I had the exact same issues. When seeking advice, I was told several things by several different students and faculty and really tried them all until I found what worked for me. A lot of people told me to do an initial prep the width of the 330 on a highspeed (so basically just run the bur through the prep design) then go through the rest with a 330 on a slowspeed. However, I was accomplishing very little with the slowspeed as far as widening the prep and I did not have enough control of the highspeed to be able to keep it from getting too wide.
One professor strongly suggested that I learned to "slowspeed the highspeed" meaning control the rheostat to make the highspeed go slower. This worked wonders as it smooths the walls and floors beautifully and takes on enough tooth structure that I can control it. After experimenting with this, I found that it worked wonders and have used it since. I don't really use the slow speed on Class I and Class II preps anymore and only really touch it when I am learning a new prep so that I can make sure I understand what needs to be done to get the desired result.

 

[schmoob]

Hi all,

I'm a D1 and have just been introduced to operative dentisty. As of now, we're working on class I amalgam preps. I've been told a number of different techniques, and I'd just like to hear imput from some of the more experienced dentists on this forum as to what their protocol is/bur selection/electric vs airdriven handpiece usage. If you could, as much detail to your procedure as possible would be awesome.

So far, I've tried using a 330 and a 245 on a high speed airdriven handleice, afterwards using a 957 on an electric handpeice at 10k rpm to smooth the floor. Both times my isthmus was pretty wide and the walls very jagged, but the floor wasn't too aweful. How can I prevent giving away too much width? What are your opinions for finishing the walls making them more smooth?

Any input is greatly appreciated, thank you.

It's not easy, don't worry.
1st step is buy lots of teeth.....
Also, get yourself a quality pair of loupes.

Establish a foundation by focusing on the very most basics. Establish good finger rests, it's very important to maintain stability. Also pay VERY close attention to your movements to ensure you aren't angling the bur.
Stick to the 330 on high speed, it should be fine. You want smooth movement when creating your outline form. It should feel like it's gliding.
957 is too wide IMO. Also, unless I'm mistaken, isn't that for the pulpal floor only? It won't smooth your walls. I prefer the 56. After the 330, use 56 on slow speed IN REVERSE so you can sharpen your pulpal line angles. As you do that it'll clean the walls too. Then clean up the walls and pulpal floor with the sharp side of your hatchet.

It takes alot of practice to build the stability and control. Lots and lots of practice.

 

[cpayne03]

Thanks for the input guys, I bought a bunch of teeth and plan on trying out some different ways of going about it and the one resulting in the best prep I guess will be the one I'll stick to for now!

 

[ncide]

330 high speed for initial depth and shape, then 56 for the floor on a slow speed and finally 330 on slow speed for smoothing up the walls and getting proper angulation.

We started Class I's back in August...

 

[cpayne03]

330 high speed for initial depth and shape, then 56 for the floor on a slow speed and finally 330 on slow speed for smoothing up the walls and getting proper angulation.

We started Class I's back in August...

Wish we started back then. All we did last semester were good ol waxups...

I also wish there was a way to practice this stuff other than just at school

 

[ncide]

Wish we started back then. All we did last semester were good ol waxups...

I also wish there was a way to practice this stuff other than just at school

Which school is this? I know of some schools that don't even start any pre-clinical work until the second year.

 

[cpayne03]

Which school is this? I know of some schools that don't even start any pre-clinical work until the second year.

WVU, pretty sure operative is just a 1 semester course for us

 

[Advance]

Wish we started back then. All we did last semester were good ol waxups...

I also wish there was a way to practice this stuff other than just at school

I'm in the same boat as you. We just started doing class I last week.

 

[Blake1e]

Hi all,

I'm a D1 and have just been introduced to operative dentisty. As of now, we're working on class I amalgam preps. I've been told a number of different techniques, and I'd just like to hear imput from some of the more experienced dentists on this forum as to what their protocol is/bur selection/electric vs airdriven handpiece usage. If you could, as much detail to your procedure as possible would be awesome.

So far, I've tried using a 330 and a 245 on a high speed airdriven handleice, afterwards using a 957 on an electric handpeice at 10k rpm to smooth the floor. Both times my isthmus was pretty wide and the walls very jagged, but the floor wasn't too aweful. How can I prevent giving away too much width? What are your opinions for finishing the walls making them more smooth?

Any input is greatly appreciated, thank you.

For class 1 preps I usually use a 330 and round 4 (or whatever size round burr is appropriate for the size of prep). I start with 330 on 200k rpm. Then at the end use a round 4 burr at 4k rpm to both smooth the prep and remove whatever decay is left without doing any unnecessary reducing. If your isthmus is too wide using a 330 then use a smaller burr like a round 1 or 2 instead.

Another way to do class 1's is to make the initial prep (depth and basic shape) using 330 or a round burr. Then use a fine KR diamond with a flat tip on 40k or so rpm to reduce and smooth where needed.

After enough practice youll be able to do an entire prep without changing burrs.

 

[ncide]

For class 1 preps I usually use a 330 and round 4 (or whatever size round burr is appropriate for the size of prep). I start with 330 on 200k rpm. Then at the end use a round 4 burr at 4k rpm to both smooth the prep and remove whatever decay is left without doing any unnecessary reducing. If your isthmus is too wide using a 330 then use a smaller burr like a round 1 or 2 instead.

Another way to do class 1's is to make the initial prep (depth and basic shape) using 330 or a round burr. Then use a fine KR diamond with a flat tip on 40k or so rpm to reduce and smooth where needed.

After enough practice youll be able to do an entire prep without changing burrs.

Round 4 for an amalgam prep? Your angles will not be ideal.

 

[ncide]

There's a reason why some schools don't teach operative until the second semester. Wax-ups are designed to help you understand and see the dental anatomy before you start irreversibly poking holes in teeth.

We studied dental anatomy and carved teeth out of wax congruently, and also worked on honing our hand skills during that time as well.

 

[vk223]

Hey I'm also a D1. #330 has a better length, but I feel like you have to be more skillful for the isthmus since the width is a bit wider than #329. Most of us use #329 here instead of #330, because #329 has a smaller diameter (0.6 mm I believe). So it allows a little more room to smooth out that isthmus later on. And yeah, don't make isthmus too wide initially. Smooth it out to make it 1mm wide.

 

[xoltarin]

You should be able to do that prep with a 330 bur and smooth out the walls and floor with 556 bur. On real pt.s even a 330 can be enough.. as for learning try drawing your preps with a pencil before you begin and mark the isthmus width.

Sent from my SAMSUNG-SM-G920A using SDN mobile

 

[cpayne03]

Anyone have any tips on class V preps? I found that using the slowspeed under 12k helps a lot when I'm doing our PAs. I understand this isn't practical on patients, so I use the airdriven high-speed to practice.

For graded work, at least on our fake teeth, I have so much more control and do better work by just starting with the electric at 12k using a 329, progressing to:
34 bur at 8 to 10k
34 at 3k for slight refinement
Hoe and chisel lightly for walls
Literally scraping a 1/4 round bur gingivally and occlusally for retention (actually does a great job...I swear)
Lastly, 34 at just a few hundred rpms to really smooth everything out good

 

[cpayne03]

Btw, one thing I found that helps (may eat up time, but helps) is starting with a new set of burs after each PA and using them till the next PA. They're so dull it's hard to make a mistake honestly. It'll take forever, but on a PA what's ultimately at stake is your grade, so might as well take whatever you can for advantage.

 

[toofdoc22]

As someone else said, buy lots of teeth. There's no substitute for practice. What I like to use is a 556 diamond. I think the tip size is 1mm. Its more expensive but I can achieve outline form, flattening of pulpal floor and smoothing of all walls with one bur.

 

[virajpatel]

Our sim lab instructor does not allow us to use slow speed on the Class I. We are also limited to 330 and 245 on the high speed handpiece. Is there anyone that can provide a set of directions on how to do a class I on the occlusal of molars and premolars. Is the idea just to follow the grooves and shape comes? Also, my indirect vision sucks, I find myself hunching all the time to see the tooth i'm working on. Any tips on how to work on indirect vision, i feel like there needs to be a whole class just to teach that.

 

[ncide]

Our sim lab instructor does not allow us to use slow speed on the Class I. We are also limited to 330 and 245 on the high speed handpiece. Is there anyone that can provide a set of directions on how to do a class I on the occlusal of molars and premolars. Is the idea just to follow the grooves and shape comes? Also, my indirect vision sucks, I find myself hunching all the time to see the tooth i'm working on. Any tips on how to work on indirect vision, i feel like there needs to be a whole class just to teach that.

The indirect vision comes with practice. It takes time, so don't fret if you don't get it right off the bat. It took me months.

You can slightly depress the rheostat to get the high speed to spin at lower RPMs like a slow speed. Just follow the grooves, keep the bur centered and controlled, and refine it at lower RPMs after you've established the main parameters of your prep at high speed.

 

[TanMan]

Once you start getting more practice on patients, you can start prepping by feel and not rely on vision as much. You will have developed a tactile sensation for caries. The way your bur moves through solid tooth structure vs carious tooth structure is something you'll learn after you master indirect vision.

 

[InformMe123]

Any give tips for Class 2 preps? Also, its confusing how everyone uses different burs for the same prep, how is it in real practice?

 

[ncide]

Any give tips for Class 2 preps? Also, its confusing how everyone uses different burs for the same prep, how is it in real practice?

Generally the 330 is the workhorse that most use. You can use a 330 or 245 to drop the box.

 

[Screwtape]

Any give tips for Class 2 preps? Also, its confusing how everyone uses different burs for the same prep, how is it in real practice?

Everyone has their favorite burs. Mine is the 557. That and a round bur is pretty much all I need for most preps.

 

[786783]

Round 4 for an amalgam prep? Your angles will not be ideal.

Which angles? Internal line Angles? Pulpo-axial line angles?

 

[frozenicecreamDMD]

Which angles? Internal line Angles? Pulpo-axial line angles?

its an old post, i think it is meant the buccal or lingual walls or axial wall.
there is no way you can drill a class II/I prep with a round 4 in sim lab to an ideal standard.