Endodontic instrument standartisation

Instruments for opening and widening of canal orifices.

Equipment for endodontic treatment.

The most convenient for dental practice classification of endodontic instruments is based on their function:

1. Instruments for opening and widening of canal orifices.

2. Instruments for reaming of canal.

3. Instruments for widening of canal.

4. Instruments for obturation of the pulp space.

Gates-Glidden drills are an integral part of new instrumentation techniques for both initial opening of canal orifices and deeper penetration in both straight and curved canals. Gates-Glidden drills are designed to have a weak spot in the part of the shaft closest to the handpiece so that, if the instrument separates, the separated part can be easily removed from the canal. They come in sizes 1 through 6.

The Peeso reamer is most often used in preparing the coronal portion of the root canal for a post and core. One must be careful to use the "safe-ended" Peeso drill to prevent lateral perforation.

The Orifice Opener is more flexible than the Gates-glidden but is still recommended only for straight portion of canal.

Historically, very lit­tle was done to improve the quality or standardization of instruments until the 1950-s when two research groups started reporting on the sizing, strength, and materials that went into hand instruments. After the introduction of standardized instruments, about the only changes made were the universal use of stain­less rather than carbon steel and the addition of smaller (No. 6 and 8) and larger (No. 100 to 150) sizes as well as color coding and the re-emergence of power-driven instruments.

By 1962, a working committee on standardization had been formed including manufacturers and the American Association of Endodontists. This group evolved into the present-day International Standards Organization (ISO).

1. A formula for the diameter and taper in each size instrument and filling material was agreed on.

2. A formula for a graduated increment in size from one instrument to the next was developed.

3. A new instrument numbering system based on in­strument metric diameter was established.

This new numbering system, using numbers from 10 to 100, was not just arbitrary, but was based on the diameter of the instruments in hundredths of a milli­meter at the beginning of the tip of the blades, a point called D1 (diameter I), and extending up the blades to the end point of the blades at D2 (diameter 2) – 16 mm in length.

The full extent of the shaft, up to the handle, is in three lengths: standart. 25 mm; long, 31 mm; and short, 21 mm. The long instruments are often neces­sary when working in canines over 25 mm long, whereas the shorter instruments are helpful in second and third molars, in deciduous teeth or with the patient who cannot open widely.

Dimensions in millimeters. Revision of ADA Specification No. 28

Size	Diameter (tolerance, + 0.02mm)	Handle color code
	0.08	0.14	Cray
	0.10	0.16	Purple
	0.15	0.21	White
	0.20	0.26	Yellow
	0.25	0. 51	Red
	0.30	0. 56	Blue
	0.35	0.41	Green
	0.40	0.46	Black
	0.45	0.51	White
	0.50	0.56	Yellow
	0.55	0.61	Red
	0.60	0.66	Blue
	0.70	0.76	Green
	0.80	0.86	Black
	0.90	0.96	White
	1.00	1.06	Yellow
	1.10	1.16	Red
	1.20	1.26	Blue
	1.30	1.56	Green
	1.40	1.46	Black
	1.50	1.56	White

Дата добавления: 2014-01-05