Best Bur for typodont teeth?

[mbgandh]

question..

Right now, for most of the class I's,II's and V's, ive been using a few burs to produce an ideal prep...

330- depth cuts for any prep
56 - mostly class II's, V's
169 - divergent walls, bulk of class I work
957 - smooth out pulpal floor
34 - aid in concavity, and smooth out problematic areas on the floor

Now the carbides that they sell at the school kinda suck, and I have to end up buying burs every week or so.

I have heard great things about the 170 or 171? they supposedly take the best qualities from a 169 and the 56. I really like the 169 but sometimes its hard to gauge its depth. 56 can be too wide sometimes.

Does anyone have any tips,suggestions on where to buy burrs outside of the school store? Brand? other numbers?

thanks!
mb

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[wigglytooth]

I use a 556 bur for everything plus hand instruments (hatchet, gmt...for most preps and wedlstadt for the pulpal floor of V). If you develop your hand skills enough, you will be able to use only one bur for your entire prep. The 556 about the correct width and about half of the bur is the depth you need to be. The trick it to be steady and to avoid trimming down your walls while increasing depth or smoothing the floor. It's difficult when you first start, but with practice, it gets easier. Try it on the desktop first and then try it mounted.

The plastic typodont teeth are killer on your burs, especially if you don't have any water to cool your stuff down. If you work slowly though, you should be able to cut a nice prep even with a dulled bur. I know it's always nice to have a fresh one, but if these preps aren't in people or on a test, it doesn't matter too much.

Good luck!

 

[ingemar]

same as wigglytooth...556 straight-fissure for all classes 1, 2, 5...sometimes start with a smaller bur (256 pear-shaped) for the proximal boxes. hand tools to make smooth. 1/4 round low-speed for retention grooves. the burs last me 3-4 teeth before they start burning up the plastic, but you just deal with it and then on exams use like a new bur for every surface. try ebay.

 

[dentstd]

Bur burns result from the massive heat generation without adequate cooling. Even if the water is turned on, you have to make sure the handpiece blows water in the right direction and that the path of the water spray is unobstructed. If you're drilling deep into the tooth, there's a chance that the high occlusal edge of the tooth is blocking the water, so make sure you have an unobstructed water spray. Fix that and your burs'll last much longer.

The 556 bur may not be the best bur to use, because it doesn't cut the right cavosurface angulations, and it cuts sharp line angles. Good for fracturing the tooth.

Most the burs the school offer you are good enough. It's a matter of using them at the right time. Try the course grain (green band) to get more life out of them, but be cautioned that it doesn't cut as smoothly. It cuts more wavy ridges...like ruffled potato chips, so you may want to take a medium grit (blue band) bur to smoothen everything. Our professors don't care if we use course grit burs.

Cutting typodont teeth is different from cutting natural teeth. I use different burs depending on which type. If you're going to use one bur for everything, use the 245 (on real teeth). You can make everything smooth, because dentin is crystalline. On typodont teeth, it doesn't smoothen very well, so the 330 diamond does that job better.

 

[dentstd]

question..

Right now, for most of the class I's,II's and V's, ive been using a few burs to produce an ideal prep...

330- depth cuts for any prep
56 - mostly class II's, V's
169 - divergent walls, bulk of class I work
957 - smooth out pulpal floor
34 - aid in concavity, and smooth out problematic areas on the floor

Now the carbides that they sell at the school kinda suck, and I have to end up buying burs every week or so.

I have heard great things about the 170 or 171? they supposedly take the best qualities from a 169 and the 56. I really like the 169 but sometimes its hard to gauge its depth. 56 can be too wide sometimes.

Does anyone have any tips,suggestions on where to buy burrs outside of the school store? Brand? other numbers?

thanks!
mb

170/171 are just thicker versions of the 169

Microcopy makes great burs, but they're kinda expensive and they only come in bulk. Bursusa does business on ebay, and they're low cost and effective. Their course burs last forever, but be cautioned that their products don't always match the pictures, namely their pears and inverted cones. (As a general rule, don't try to buy the 34D and 330D anywhere. They don't exist outside of dental school, so that's an incentive to stop using them now. Why try to master dentistry using a bur you can't buy commercially?) Don't buy Midwest, because their burs aren't standardized shapes.

My overall recommendation is that you continue to buy from your school. Burs from other companies aren't really better. The biggest difference is the grit size. Larger grits last longer. Buy course grits from outside companies if your school doesn't offer them. (They do NOT cut more efficiently. I verified this via a pubmed search.)

 

[wigglytooth]

The 556 bur may not be the best bur to use, because it doesn't cut the right cavosurface angulations, and it cuts sharp line angles. Good for fracturing the tooth.

Sharp line angles are rounded when cutting, hand instruments for smoothing any other line angles. It's never been a problem.

 

[Brokenbus]

A 329 or 330 has never failed me. I'll use a 245 in the slow speed to smooth the walls afterwards

 

[dentstd]

Sharp line angles are rounded when cutting, hand instruments for smoothing any other line angles. It's never been a problem.

You won't know if it's a problem until years down the road when the patient comes back with a fractured tooth. Why not just use the 245 and have the bur round out all angles for you? A nice broad "angle" that the textbooks have pictures of.

 

[dentstd]

A 329 or 330 has never failed me. I'll use a 245 in the slow speed to smooth the walls afterwards

Those are all carbides, right? The 330 comes in both a diamond and carbide form, but they're radically different. The 330 diamond is twice as long as the 330 carbide, and the 330 carbide comes in different taper angulations, depending on the manufacturer. Some are tapered, some are straight. All have rounded edges.

The 330 and 245 carbides are the 2 recommended burs for operative. Anything else cuts the wrong form, and you'll likely cause problems for the patients later down the road.

 

[HupHolland]

I agree with dentstd. the 245 and 330 are much better choices for operative as they are tapered and create smoother line angles. the 556 is good for refining preps on slow speed.

also there is no need to really tilt the 245/330 to obtain the proper convergence as the taper of the bur accomplishes it for you.

Hup

 

[wigglytooth]

You won't know if it's a problem until years down the road when the patient comes back with a fractured tooth. Why not just use the 245 and have the bur round out all angles for you? A nice broad "angle" that the textbooks have pictures of.

The operative professor claims that the 245 won't give you the parallel walls you're looking for, and no one here has ever suggested using it... So I don't use it... and get the results approved by the staff. The 556 on a slow speed, like someone else said, is exactly how I round my stuff out for the external outlines. Hand instruments for the pulpo-axial line angle. Somehow I don't think that everyone at SB could be wrong about the 556😕

 

[HupHolland]

The operative professor claims that the 245 won't give you the parallel walls you're looking for, and no one here has ever suggested using it... So I don't use it... and get the results approved by the staff. The 556 on a slow speed, like someone else said, is exactly how I round my stuff out for the external outlines. Hand instruments for the pulpo-axial line angle. Somehow I don't think that everyone at SB could be wrong about the 556😕

I don't think anyone is "wrong." You will realize soon, if you haven't already, that there are a lot of ways accomplishing the same thing in dentistry. What works in my hands may not work in yours and vice versa.

In addition, some schools teach parallel walls for operative, others teach divergent/convergent walls. I don't know if either method has been proven to have any more success the the other.

At the end of the day it is important to understand why you're doing what you're doing (this is what makes you a doctor, not a mechanic). And if you can accomplish the same procedure differently than I do, then so be it.

Hup

 

[dentstd]

The operative professor claims that the 245 won't give you the parallel walls you're looking for, and no one here has ever suggested using it... So I don't use it... and get the results approved by the staff. The 556 on a slow speed, like someone else said, is exactly how I round my stuff out for the external outlines. Hand instruments for the pulpo-axial line angle. Somehow I don't think that everyone at SB could be wrong about the 556😕

That's because you don't want parallel walls. Slightly convergent walls (3-4 degrees taper) give you the retention and resistance form you want. You create a well that locks the restorative material inside the tooth. Parallel walls give you no retention what-so-ever, although you get more resistance form. I have to clue what Stony Brook's reasoning is.

 

[armorshell]

That's because you don't want parallel walls. Slightly convergent walls (3-4 degrees taper) give you the retention and resistance form you want. You create a well that locks the restorative material inside the tooth. Parallel walls give you no retention what-so-ever, although you get more resistance form. I have to clue what Stony Brook's reasoning is.

Retention comes from a couple of things:

1. Modulus of elasticity of dentin: On condensation, the dentin flexes slightly creating a natural undercut the amalgam locks into.

2. In a parallel form prep you place .5mm retention grooves in dentin just axially to the axiopulpal line angle.

For finishing I'd recommend using a 56 instead of a 556 considering the 556 is crosscut which makes it more aggressive and thus less suitable for finishing. As you've learned today, there are two common schools of thought on how retention form should be established in amalgam preparations. Make sure you figure out which one your local regional board expects to see before you take it. 😉

 

[dentstd]

Even if you were to do parallel walls, there's another bur that cuts a better shape. I havn't seen it at the school's store, though. You'd have to order it directly. It's the 835 and 835R diamonds. They're both cylinders. The 835 is supposed to have sharp corners, but due to manufacturing limitations, it's slightly rounded. The 835R has more pronounced roundedness. Any of these 2'll give you slightly better form that the 5x-based series (56, 1156, 156, 57, 1157,...etc)

 

[monreal]

Retention comes from a couple of things:

1. Modulus of elasticity of dentin: On condensation, the dentin flexes slightly creating a natural undercut the amalgam locks into.

2. In a parallel form prep you place .5mm retention grooves in dentin just axially to the axiopulpal line angle.

1- Is this actually proven? Friction wouldn't surprise me though.

2- I couldn't imagine how to put grooves axially to the axiopulpal angle. Do you mean the two proximal grooves (axiobuccal and axiolingual)? These don't provide any retention to the occlusal part of the filling.

 

[dentstd]

1- Is this actually proven? Friction wouldn't surprise me though.

2- I couldn't imagine how to put grooves axially to the axiopulpal angle. Do you mean the two proximal grooves (axiobuccal and axiolingual)? These don't provide any retention to the occlusal part of the filling.

Sounds highly time-consuming and complicated. Retention grooves suck. End of story. You know how people can overcome all this? Use the 245 to get converging walls, and problems go away.

 

[monreal]

Sounds highly time-consuming and complicated. Retention grooves suck. End of story. You know how people can overcome all this? Use the 245 to get converging walls, and problems go away.

Agreed. But I was just trying to learn from Armorshell post.

245 is the best for me now. I first used 330. Comparing to 245 it's better 'cause its 2 mm long (right depth), downside it gives too much roundness in the angles.

 

[TheWiredNerv]

I use 556 for almost everything except Class II. It was said from the beginning of school year that literature shows parallel walls are fine for amalgam retention. Facualty here that use 556 for amalgam prep for years have not complained about amalgam failure due to retention form.

There are more than one way to skin a cat.

 

[armorshell]

1- Is this actually proven? Friction wouldn't surprise me though.

2- I couldn't imagine how to put grooves axially to the axiopulpal angle. Do you mean the two proximal grooves (axiobuccal and axiolingual)? These don't provide any retention to the occlusal part of the filling.

I can't find a citation from Summitt, pubmed or any of the operative faculty (I think they're all at the ADEA annual session) to get you something tangible at the moment.

Yes I am talking about retention grooves is those areas, and they're only recommended by Summitt for additional retention of the proximal box, considering the retention you get from everything else in the occlusal area. I think someone else mentioned that you get a good amount of retention from friction in a parallel prep as well, which I forgot to mention.

 

[armorshell]

I use 556 for almost everything except Class II. It was said from the beginning of school year that literature shows parallel walls are fine for amalgam retention. Facualty here that use 556 for amalgam prep for years have not complained about amalgam failure due to retention form.

There are more than one way to skin a cat.

IIRC the reason behind the "parallel wall prep" is the majority of amalgam failures are due to failure of resistance form (fracture) rather than failures of retention form.

 

[Brokenbus]

Those are all carbides, right? The 330 comes in both a diamond and carbide form, but they're radically different. The 330 diamond is twice as long as the 330 carbide, and the 330 carbide comes in different taper angulations, depending on the manufacturer. Some are tapered, some are straight. All have rounded edges.

The 330 and 245 carbides are the 2 recommended burs for operative. Anything else cuts the wrong form, and you'll likely cause problems for the patients later down the road.

yeah youre right, i was talking carbide. 329 works for premolars and small conservative preps thats why I like it.