need tips on doing cavity preps in Operative

[mike05tusdm]

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Hello All,

This is a very general post, but I'm looking for all of the nuggets of wisdom I can find!

Anyway, we have our first practical(MO on #18) next week. We've been spending many hours in preclin trying to get good. I've been drilling like crazy for the last couple weeks, I see some improvement, but I don't have consistency-I'll do a really good prep, then I'll do a lousy one right after.

One problem is with getting the occlusal portion at the right depth. They want 1.5mm in the central fossa, so I use a 330(which is 1.5mm) long to get the right depth, but while doing the rest of the occlusal, I have trouble keeping from cutting the prep a little deeper.

Another is seeing the mesial box-I'm angling the typodont towards me, but I have trouble seeing the buccal and lingual edges of the box(so often the pulpal floor is not even). I'm going in with a 330 and using a "pendulum" motion to make the box and using hand instruments afterwards to refine the prep.

Also, the practical is in the simulation clinic on manikin heads, not just on typodonts, so it makes vision even harder with the entire head in the way, I have a lot of trouble angling myself so I can see the proximal box.

I guess it's really hard to give pointers on a message board, but I'm open to any ideas people have had. I'm sure a few of my classmates are on this board as well. 🙂

Mike

 

[eleannaDDS]

Hi Mike,

We've been drilling since the second week of September and still, most of us have our ups and downs - so don't get discouraged if you end up with a lousy prep once in a while. What matters is your overall trend throughout the year.

We have our third practical next week, on operating in the maxillary arch as well. We haven't done any preps on 3rd molars, but I imagine that it would be more difficult than the 1st and 2nd molars we've been working on due to vision limitations.

We're working on mannikins as well so I totally understand your frustration about not being able to see interproximally very well. After assisting in the clinic with real patients, I've realized that it doesn't get any easier so it's important that you just find the best positions to see various aspects of the tooth. There isn't a single working position where you'll be able to see everything at once.

When you're cutting the central fossa area, do you cut to spec immediately? If so, try obtaining a depth of 1.25 mm and then move on. I've found that you end up removing quite a bit of additional material when you are smoothening out floors and walls. Besides, you can always cut more later, but you can't piece back what you've cut.

Some of my classmates like using the 330, but I've had more luck with the 245 because of the shape of the bur itself. I find that it's really easy to undercut with the 330, possibly creating and uneven floor or angled axial walls. You might find this angulation problem in your proximal boxes if you're using an 'pendulum' motion.

In terms of seeing the mesial box on maxillary molars, I usually either use direct vision from in front of the patient to judge whether the sides are parallel to the long axis of the tooth; look from the front of the patient with a hand mirror to look at enamel rod correction; but mostly I look occlusally with a hand mirror in my normal working position.

The best positions, though, is those that are most comfortable for you. This is your opportunity to find them so keep on moving your chair and your mirror around until you find what's good for you. I hope that some of my thoughts help, or at least give you some other ideas. Keep in touch! I'm in first-year too and I'm interested in what you guys at Tufts are learning. It seems like there's a bit of variation just in terms of operative. It'll be cool to find out what techniques you do differently. I'll send you my email address by private message.

Good Luck!

 

[Big_Poppa DDS]

Tooth number 18 is a second molar, lower left second molar. The US dental schools don't use the system that the rest of the world does, Tooth 1, 8 would be tooth number 1.

As far as burs when I was in pre clinic I used a 330 and did relatively well, because of its inverted cone shape and that its 1.8 mm depth is almost ideal and gives you some room to smoothen the floor. If found the best way to smoothen the walls of the prep is pumping the foot pedal of the high speed - at first I used the slow speed but I don't think that was the best way, just be careful not to over widen the isthmus. Also, make sure your outline form is rounded and bevel the axiopulpal line angle.

Good luck, Don't get discouraged if you don't do well, I remember I totally bombed my first practical 67%, an MO on 31, but by the end of the course I scored an 86 on another class 2 amalgam prep.

 

[eleannaDDS]

Temporarily forgot that American schools didn't go by the universal system. A prep on 18 would make more sense then. Only went by instinct.

 

[Big_Poppa DDS]

I understand, I am taking the Canadian Board next month and have to get used to the other system.

 

[mike05tusdm]

Thanks for all the tips for everyone who responded-some were useful. I wish I had more time and more teeth to work on this, but I've done all I could. Sigh....

The practical is tomorrow, I'm sure I'm going to bomb it-Ack! I practiced all I could, got sick of buying more teeth, so I just want it to be over and move on. The next isn't for a month, and the last three are in May/June Oh well, hope I can do semi-decent on the last 4!

MH