Lentulo spiral

Dental rotary instruments (hereinafter also referred to as drills) are differently designed and stocked approaches that are clamped in dental angle handpieces or turbines or - the drills in a drill comparable. The handpiece drill fit into the commonly used in dentistry technology handpieces.

The rotary instruments are distinguished according to

  • The material of the work piece,
  • The shape of the work piece,
  • The shaft ( diameter and length),
  • The size of the working part (diameter ) and
  • The scope.
  • 3.1 FG shank
  • 3.2 Elbow shaft ( RA)
  • 3.3 handpiece shank (HP and HPT)
  • 4.1 Steel and Carbide
  • 4.2 diamonds
  • 4.3 Ceramic abrasives
  • 4.4 Flexible polishing pad
  • 4.5 Other Forms

Generally

The portions of the drill can be divided into the head, neck and stem, wherein the head is the working portion and the shank of the fastener is used in the drive.

Important features for the quality of the drills are sharpness, material hardness and concentricity. Equally important is the shape accuracy of the instruments, if used in succession.

The drills are identified by color markings, which gives information about each of the diamond grit the teeth or properties.

Materials utilized

Steel

Steel instruments consist of a tungsten -vanadium alloy or stainless steel and are manufactured from one piece. They are particularly sharp in new condition, this sharpness atone but a comparatively fast. They are primarily suitable for the processing of dentin, ie, for excavating (boring ) of the carious defects. And milling to the processing of gypsum and plastic are made of steel, as well as bone milling (e.g., Lindemann milling). Today, steel instruments ( stainless) almost exclusively in oral surgery, implantology or be used. In the treatment areas filling therapy and crown and bridge restorations rather diamond and carbide tools are used.

Carbide

Carbide drills are made from high-density fine grain carbide. They are harder than steel drill and ensures a longer life, without substantially losing sharpness. They can be used for the same purposes as the drill steel, because of its hardness but also suitable for removing the metal fillings ( amalgam ) or metal crowns and bridges. Disadvantage: they are more brittle than steel drill, causing an increased risk of fracture means.

Steel or carbide tools with a fine tooth are referred to as finishers and used for smoothing.

Diamond

Diamond-coated tools have a core made ​​of stainless steel, which is coated by electroplating with diamond grains with different grain sizes are available. The classification and color coding of the grain sizes is specified in DIN EN ISO 7711-3. They are used primarily for machining of the tooth enamel, ie in the preparation of the teeth for the supply of dental crowns and Füllungskavitäten. They are almost exclusively with FG shank (see below ) and are particularly suitable for dental turbines and special ( high-speed ) angle heads.

Ceramic abrasives

Ceramic abrasives also have a core of hardened steel. By means of a binder is this equipped with grains of corundum or silicon carbide. They are used only in exceptional cases, the processing of dental hard tissues, but the processing of metals, such as the filling or denture correction.

Flexible polishing pad

In elastic polishers (also called rubber polishers ) precision grinding and polishing agents are mounted on a stainless steel shaft with a binder of polysiloxane and rubber. With its fine-tuning, they are suitable to polish the surface of plastics, ceramics, precious metals, chrome cobalt, titanium, filling materials, but also of the natural teeth.

Shafts

The shank types are classified according to DIN EN ISO 6360-1. The standard describes the shafts with a three-digit code (XXX ), where the first two digits of the type and diameter of the shaft used to describe: 10 = hand shank Ø 2.35 mm; 20 = angle shank Ø 2.35 mm; 31 = FG shank ø 1.60mm.

The third digit of the code describes the qualitative aspect ratio equal to each other shank types: 2 = very short, 3 = short, 4 = normal, 5 = long, 6 = extra long

Example: An angle shank with normal length is named according to DIN EN ISO 6360-1 with " 204 ". Longer instrument shafts can be 205 or 206.

FG shank

The designation FG shank comes from the English: Friction Grip ( "stiction "). The FG shank is smooth and has a standard diameter of 1.6 mm. FG shanks fit in dental turbines and special ( high-speed ) angle heads. The instruments ( here example round bur ) may have a different total length, from short (16 mm) above normal and long to extra- long ( 25 mm).

Elbow shaft ( RA)

The elbow - stem is also known as RA shaft (from the English: Right Angle ). It is normally locked manually in the angle head and therefore has a notch on the shaft end. RA- shafts have a diameter of 2.35 mm and an overall length of between 22 mm and 34 mm.

The total length of the instruments is affected by the length of working part, that an elbow instrument with shank type 204, with a longer working part also a greater overall length than the corresponding round bur.

Handpiece shank (HP and HPT)

Handstückschäfte (HP = Handpiece ) also have a diameter of 2.35 mm and between 34 mm and 70 mm long. You have no notch that is attached by a chuck in the handpiece.

For Dental handpieces there are also thick stems ( HPT Handpiece Thick ) with a diameter of 3.0 mm and a length of 34 mm and 44.5 mm.

Form of the working part, application areas and speeds

Steel and carbide

Almost all instrument types are available, which are classified according to ISO 2157 in different sizes.

One of the most used and most versatile instruments is the round drill which is also called round bur. This and the Radbohrer, the inverted cone, the fissure and more here unmapped steel or carbide drills are recommended for excavating used (removal or " boring " carious dental hard tissues ), where Radbohrer and inverted cones serve, in particular, to prepare sub -sections for anchoring plastic filling material. However, metals and plastics can be processed with it.

Finishers are used to smooth the surface, used surgical instruments ( eg milling cutters after Lindemann ) for bone and plaster and plastic milling for development of models and prostheses.

The instruments shown should be min -1 ( revolutions / minute) and 40,000 min-1 used at a speed between 5,000.

Before insertion of dental implants, special instruments are used, the used part of the implant system. This specially adapted to the diameter and length of the implant drill to be at a very low speed ( approximately 2000 min-1 ) was used to prepare the implant in the bone. These instruments have in part a so-called inner cooling, where through a small channel through the shank physiological saline solution is fed directly to the working tip to flush out bone chips or debris and to prevent overheating and damage to the bone ( Thermonekrose ).

Diamonds

Diamonds are suitable to process even the very hard enamel. They therefore serve primarily the preparation of Füllungskavitäten and teeth to receive crowns. There are diamonds of different grain size on the market. Thus, for example, a tooth stump can be smoothed before the impression. Many manufacturers mark the grain with color rings.

The machining of metals with diamonds is not advised, because these will be " smear", lose focus and will quickly become unusable.

With smaller diamonds full speed dental turbines can be used by up to 400,000 min -1. With diamonds with a larger diameter, the speed must be reduced because of the enormous centrifugal forces can otherwise lead to breakage of the instrument. At these high speeds, cooling with water (spray) is essential, because at points very high temperatures occur that would damage the tooth.

Ceramic abrasives

Ceramic grinding body (also called calculi) used to work pieces (especially chrome dentures and other ( precious) metal work ) to prepare and smooth. They are available in different grain sizes are available, which can be identified by their color. Even natural teeth and dentures can be worked well with ceramic grinding wheels, for example, to correct the occlusion.

The optimum speed is depending on the material to be processed between 20,000 and 50,000 min-1 min -1.

Flexible polishing pad

(Also called rubber polishers ) Flexible polishing pad can be used as the last step in the preparation before the high gloss polish with polishing paste. The workpiece can be very hot.

They achieve their optimum effect depending on the grain and workpiece at a speed between 5,000 rpm and 20,000 rpm 1 -1.

Other forms

There is a wealth of other forms for any purpose, dental and dental technical working: Disc -shaped, flame shaped, pear-shaped, lens-shaped, flame -shaped, cup- shaped, etc. Also Mandrelle as a support for ( diamond coated ) cut-off wheels and Schmirgelpapierträger and felt cone, goat hair brushes and Leinenschwabbeln as a carrier for Bimspulver and polishing pastes are available.

Root canal instruments

In addition to the hand tools are also mechanically driven rotary instruments available for root canal treatment: Giro -files, Hedstrom files, reamers, but especially root filler ( Lentulo, named after Henri Lentulo ). These instruments must be operated with special elbows in part, strengths and different lengths are available in many ( marked with color rings ).

Swell

  • Walter Hoffmann- ax handle: Encyclopedia of dentistry, Quintessence Verlag, Berlin
Occlusion (dentistry)
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