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Burs for dental drilling hand-pieces

Development of drilling teeth
Research has uncovered examples of Drilling teeth as long ago as 7,000 years and a pneumatic powered drill burr was produced in 1840s.  By 1914 electrically powered dentist hand-pieces were available which could reach speeds of 3,000rpm. The dental drill we know nowadays is an air turbine drill and was initially developed in New Zealand in 1949 by SIr John Walsh. This was further developed in the USA was more widely produced in 1957. Current dentist drills usually rotate at rates up to 400,000 rpm and a few approaching 800,000 rpm.  The slower dentist drill, which is the sensation most people dislike even more with its heavy grating rotates at around 40,000 rpm because of the extra torque needed to drill out the final pieces of the caries from the tooth.

How is a bur designed?
The actual cutting tool known as the dental bur is most often made of one piece of extremely hard metal.  This is commonly steel with a tungsten carbide coating but sometimes solely comprises tungsten carbide. A few burs also have a diamond coating on the drilling tip.

Burs have three elements - the head, neck and shank.  They come in various shapes and dimensions according to the various drilling procedure needed.

The head contains blades which are the actual cutting tips.  They are positioned at various angles to produce a variety of cutting finishes.

The most common bur designs are round, inverted cone, straight fissure, tapered fissure with each having a different function for most dental cavity work.

Identification of burs
There is a cross national numbering system employed for the burs which makes it easier for dentists or dental office staff to order dental burs from dental supplies companies.  Therefore there is no need to check component numbers between suppliers.

Round burs are numbered with the smallest numbers for ¼, ½, 1, 2, 4, 6, 8 and so on.
Straight fissure burs begin with 50.
Cross-cut straight fissure burs are numbered from 500 and tapered-fissure burs start at 700.

Dental burs are the element of dentist drills that we dislike the most because it is the part that cuts into the tooth itself but without dentist burs, we would be suffering far greater pain for much longer.

About the Author

Rob Keating works at Aluro Dental - http://www.aluro.co.nz/ - suppliers of dental products throughout New Zealand.

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DIY- Smoke coming out of drill, part 2?

Yesterday I had asked a question about smoke coming out of drill when I was drilling holes in wood-

http://answers.yahoo.com/question/index;_ylt=Atnx97yw7kuVIc0A7BgPPIHsy6IX;_ylv=3?qid=20100820120617AAnIgA7

I thought I had overworked the drill but out of curiosity when I opened the drill to my surprise(horror) I found out that the metal coating over the armature was colliding with the motor's electromagnet and getting abrased away. This is not OK. Right?? There is burnt metal powder inside of the drill now due to abrasion. The only way I was able to make the drill work again was by removing the diaphragm(the separator thingy between armature and the gear which rotates the drill bit). This somehow fixed it. But the metal shell thing which covers the armature is badly damaged at some points. Whats the deal. How did this happen? It took me five hour worth of effort to repair it.

Liker Jim said , toss it and buy a new one, there not made to be repaired any more,
harbor freight.com has a good cheap one,
don,t keep using it you may get electrocuted ,

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