how to cut class III preps?

[StarCraft]

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hey guys, we just started school and we didn't learn how to prep class IIIs yet. i was wondering if you could help me. i've just been mounting some natural teeth and practicing on class I and IIs. how do you do class IIIs? i know it involves the proximals on anterior teeth. which walls diverge? i know the general shape that it looks kinda like a half circle but i don't know which walls converge or diverge. thanks!

 

[Tooth Pulp]

hey guys, we just started school and we didn't learn how to prep class IIIs yet. i was wondering if you could help me. i've just been mounting some natural teeth and practicing on class I and IIs. how do you do class IIIs? i know it involves the proximals on anterior teeth. which walls diverge? i know the general shape that it looks kinda like a half circle but i don't know which walls converge or diverge. thanks!

So what's going on? You haven't officially had operative yet, but you are practicing? I wouldn't suggest any drilling until you've been instructed. The worst thing you can do is develop bad habits.

 

[StarCraft]

we did some class Is and IIs briefly in freshman year. can you actually help now?

 

[Noble6]

Wall inclination doesn't really matter since it's composite. Just go in with a round bur angled towards the mesial. Make sure you break contact on the gingival. You want the incisal and gingival walls to be parallel. You want to go deep enough to just see light through from the facial.

 

[Tooth Pulp]

Use either 1.2 round or 170. Keep bur perpendicular to the tooth surface. Establish depth and outline. Inciso-gingival width is 1.5-2mm. depth is about 1.25 at the gingival and 1.50 at the incisal. Extend mesial-distally about 1.25 and like the other poster said, you want to be able to see a little light coming through in the embrasure. Extend about .5mm into facial embrasure and that should be enough. Outline is basically rectangular. 90 deg. cavo-surface margins. Retention using a 1/4 round in the incisal wall and I think a little notch in the axio-gingival wall.

 

[Mackchops]

Bury a 330 depth of cutting head. Go up. Go down. Extend as necessary if soft. Fill. Repeat.

 

[omaralt]

Use either 1.2 round or 170. Keep bur perpendicular to the tooth surface. Establish depth and outline. Inciso-gingival width is 1.5-2mm. depth is about 1.25 at the gingival and 1.50 at the incisal. Extend mesial-distally about 1.25 and like the other poster said, you want to be able to see a little light coming through in the embrasure. Extend about .5mm into facial embrasure and that should be enough. Outline is basically rectangular. 90 deg. cavo-surface margins. Retention using a 1/4 round in the incisal wall and I think a little notch in the axio-gingival wall.

measurements mean nothing if your doing composite; it's all about caries removal. i remember when i did my first class III i went by the measurements; stopping every few mins to measure w/my probe. my instructor laughed at me and told me to "just get the damn cavity out".

to the OP; please dont try to learn this on your own; wait until they teach you how to do it; one of the hardest things to do is un-learn bad habits/techniques. learn it properly from the get go and you'll be in better shape. relax; no matter how much you know or do; your not going to graduate early

 

[Quizno]

Can anyone discuss the techniques they use to restore the Class III? Specifically how to avoid a gingival overhang

 

[HupHolland]

Can anyone discuss the techniques they use to restore the Class III? Specifically how to avoid a gingival overhang

Assuming I have incisal contact still intact, I use a mylar strip with no wedge.

I place the strip in the sulcus and have my assistant hold it in place from the facial. I place enough composite into the preparation just to barely overfill to avoid voids. I then fold the strip over the lingual of the prep/tooth and press it against the tooth, curing for 10s from the incisal, release mylar, cure 30s from lingual.

Finish with flame shape diamond to remove any gingival overhang or facial excess and football carbide/diamond to finish lingual cingulum/marginal ridge.

Hup

 

[Mackchops]

Can anyone discuss the techniques they use to restore the Class III? Specifically how to avoid a gingival overhang

Wedgy wedgy wedge! And they come in different sizes for a reason. Use one that fits to hold your mylar strip in place and place it tightly enough to get a little separation between adjacent tooth. Fill. Use your fingers to squeeze composite into contact. Cure. When you remove everything the contact should be a tad too tight - easier to remove than add. Polish and give patient a mirror to show off your mad bonding skillz.

 

[dentalWorks]

measurements mean nothing if your doing composite; it's all about caries removal. i remember when i did my first class III i went by the measurements; stopping every few mins to measure w/my probe. my instructor laughed at me and told me to "just get the damn cavity out".

to the OP; please dont try to learn this on your own; wait until they teach you how to do it; one of the hardest things to do is un-learn bad habits/techniques. learn it properly from the get go and you'll be in better shape. relax; no matter how much you know or do; your not going to graduate early

Hes a Class-A gunner.... trying to Rambo the hand skills early so he/she spends more time with didactic

 

[FutureDent020]

measurements mean nothing if your doing composite; it's all about caries removal. i remember when i did my first class III i went by the measurements; stopping every few mins to measure w/my probe. my instructor laughed at me and told me to "just get the damn cavity out".

to the OP; please dont try to learn this on your own; wait until they teach you how to do it; one of the hardest things to do is un-learn bad habits/techniques. learn it properly from the get go and you'll be in better shape. relax; no matter how much you know or do; your not going to graduate early

You're right omaralt, as long as you preserve tooth structure, cut conservatively, and remove the carries you should be good. But in pre-operative they preach perfection i.e. measurements since caries don't exist. It's the only grading criteria. Things change in clinic. But you have to abide by measurements in pre-operative

 

[bballrules]

Sounds great, hope it won't trouble you. I think it'll be good for everyone who wants to learn. Thanks your your time.