Class 2 Proximal Box Ideal Prep: Easiest/Best Approach

[dentwiz]

Hey Guys

I am taking my board exam in couple of months and wanted some input of the sdn dental community for the easiest/best approach in doing a Class 2 proximal box ideal prep in terms of

Burs used - prep, finish
Hand piece used - high/low speed
Hand instruments used or not - if yes which ones for what purpose

Best approach on how to

break contact without touching adjacent tooth.
creating the occlusal convergence of the the facial/lingual proximal walls.
creating the bevels ( for class 2 composites ? if you have been taught to ).

I know every school has their own little way of teaching the above...and everyone's input should be helpful for any body taking the board exams.

Cheers!

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[dinesh]

We were never really taught about burs ...more or less left to experiment, what we liked best.

I usually use a small round bur to get the outline of the box, the depth etc.Slowly I near the contact point, till only a very thin peice of the enamel would remain proximally.
I take a hatchet and break it off.
Use my marginal trimmers, and thats' it.

I use highspeed for everything

 

[thedentist2005]

a round bur!!are you out of your mind thats the first time i ever heard that, you will gouge out the tooth

 

[Dr.McSultry]

yeah seriously...a round bur??...gouging + a piss poor outline form and not to mention all the lil' undercuts that you could create - I'm visualizing a prep that looks like a freakin' golf ball!

But then again, kudos to anyone that can cut a Class II prep with a round bur!

 

[dentwiz]

no helpful answers yet! only criticism of the one bad answer...come on guys...make this a useful thread for everyone taking the boards.

cheers!

 

[Googles]

If he can do it with a round bur, all the props to him. Everyone has there own way of doing things - SDN definitely has some uptight people that need to relax.

 

[dinesh]

It's the smallest round bur that we have.
I first drill a hole to around the depth to break the contact point(usaully about 3mm, sometimes a little more), then i expand it to get a slot.

I've seen some classmates use a very small tapered bur to expand the outline of the box.

 

[Tooth]

I use the garrison dental g-ring and matrix band to separate and protect the adjacent tooth.

http://www.garrisondental.com/store/ct_main.cfm

Then I use a 245 or 330 carbide to make the prep. I finish off with a biangle chisel (hatchet) hand instrument to clean up the cavosurface angles.

Sometimes I will scrape the gingival floor with a condeser to smooth it out.

http://www.hu-friedy.com/product/largeImage.aspx?ProductID=PLGSPO

 

[Teja009]

Hai friens,

This is wat the procedure that i have learnt...so read and see if it helps you

After finishin the class 1 out line we have to extend the proiximal side of the cavity So that a thin wall of about 1 mm in thick ness is left. Then take a straight fissure bur and place it proximally near the wall and cut deep to the depth needed for the proximal box preparation of approx about 2-3 mm.
then the thin wall is cut by making dents in the proximal wall and then weak wall is broken By Enamel hatchet . once the wall is broken then make a reverse S curve on the buccal side to break the contact point....

So this long procedure to explain but wen you do practically then that wud be better...

 

[dinesh]

Wow a matrix band..
We were taught to try not to use it.

 

[swhit81]

330 bur to cut the box. 699 to cut retention grooves. gingival margin trimmer to remove unsupported enamel on the gingival seat. hatchets/hoes to remove other unsupported enamel. I placed a wedge and matrix band to prevent damaging the adjacent tooth.

 

[Tooth]

It's not like you're using a normal matrix band. The garrison dental matrix is a thick piece of metal, not just like the foil-like ones you use in your tofflemeir. Check out the link in my previous post.

 

[dinesh]

I realize that. But it's what we've been taught. Of course they dont 'dissallow' it, I use it on occasion if I sence I'm going to be in a little problem, but otherwise I try to do without it.

 

[DesiDentist]

330 to create outline shape and go into dentin, 245 for box. 956 to smooth the pulpal and gingival floor. hand instruments to break contact. I sometimes use a straight/fissue bur to get a good curve on the cavosurface. Use caries detector and go at it w/ a probe to make sure there are no sticks.

DD

 

[Prosthoman]

Burs used - prep, finish
Class II amalgam prep : 330 or 334
Class II comp Prep : small round bur, or 330 work fine

Hand piece used - high/low speed
prep amalgam: high speed, sometimes you have to use slow so combination both
Prep compost: high speed, sometimes you have to use slow so combination of both

Hand instruments used or not - if yes which ones for what purpose
Absolutely used in both preps: breaking contact, enamal hatchet or any hatchet that can break contact



Best approach on how to

break contact without touching adjacent tooth.
use matrix band safest
or when droping into the box, leave at lease .5 mm if proximal wall, so thin enough that you can break it with a hand instrument.
or use thinest bur ( Brasler has thin bur) look it up

creating the occlusal convergence of the the facial/lingual proximal walls.
for both prep use 330, 334

creating the bevels ( for class 2 composites ? if you have been taught to ).
slow speed, thinnest bur you have
or hand instrument, if you are good at it
in the board, never use high speed, you might mess up



I know every school has their own little way of teaching the above...and everyone's input should be helpful for any body taking the board exams.

Cheers!

 

[nuts]

May I ask if retentive grooves are placed in composite Cl II preps? We were taught to put them in school but don't know Board requirements.

Also, would anyone recommend a flame-shaped finishing bur for the bevels?

For amalgam Cl IIs, is a gingivo-pulpal retentive groove needed? Can bonded amalgams be used or has to use varnish?

Thanks for your help!

 

[drmanpa]

here are the answers

May I ask if retentive grooves are placed in composite Cl II preps? We were taught to put them in school but don't know Board requirements.

Wreb wants you to place retentive grooves if its a slot prep , if it is conventinal prep ,its up to you. They won't take out points if you did not place them for a conventional preparation.
Also, would anyone recommend a flame-shaped finishing bur for the bevels?
You may but I usually find it difficult with it and prefer hand instruments

For amalgam Cl IIs, is a gingivo-pulpal retentive groove needed? Can bonded amalgams be used or has to use varnish?




Thanks for your help!

 

[nuts]

Thanks drmanpa! May I also ask how easy it will be to do the proximal bevels with hand instruments? It will be supported enamel in this area unlike the gingival cavosurface area. Will digging with the hand instruments chip this area easily?

 

[JakeMUSC]

#245 bur high speed. do you your outline and drop the box leaving a tiny bit of proximal wall to avoid hitting adjacent tooth. use hand instrument to punch out the thin wall and smooth rest of your prep.

 

[Twinkletoez]

First 2 things!

1. Visualize the s curve of the finalized outcome so that you will have just 1mm clearance between the opened box and the adjacent tooth. (for practice it helps to draw it on with a marker) Its a pain in the butt to try and trim off the box edges with a chisel and you could fracture cusps by doing it.

2. Wedge Wedge Wedge! This will help you from hurting the tooth next door and stop you before you ruin the gingiva on your typodont.

If you have a tendency to go too deep, use a 330 bur bc its exactly 1.5mm long. I like the 245 though.

Widen the proximal dovetail to the pre-drawn or imagined angles for the box, leaving about 1mm of the proxial wall, this will be sure to make the axial depth of the box at 1.5mm. I like to make it all even with the pulpal floor before dropping the box. Our instructors said to use a pendulum type motion to drop down. then take a chisel or hachet to snap out the remaining enamel. Running a chisel back and forth and a 556 bur will help flatten the gingival wall and make it perpendicular with the walls. To do the retentive grooves use a 1/4 round bur on slow speed. Place it in the point angle of the box and turn it on full, push into the side wall and pull upwards to the level of the pulpal wall. Do it about 3x/side and you should have some solid grooves that will hold the 23 explorer nicely.

That's my 2 cents. Hope it helps.

 

[thedentist2005]

just wanted to give some friendly advice use a carbide bur for your box, a 56,330 i personally prefer a 256, be as conservative as you can with your outline condenser must fit!! after you have your box , use a round bur on a low speed to excavte decay, i am extrememly hesitant to use a round bur on a high speed, the only time i would use it initially is when i am doing a class 3 composite

 

[ScDds]

lol Don't you have any faculty or instructor you can go to?

It is probably best that you practice and learn what is best and fastest for you.

 

[estrato]

whats the verdict on placing retention grooves in amalgam preps....and bevelling for composite preps? can someone fill me in on the details of these