Wire and Archwire Instruments
In orthodontic practice, a wide range of pliers is used for manipulating wire elements. Special pliers are used to construct appliances, with their working parts (beaks) adapted to a specific task. For example, there are separate modifications for forming angles and loops of Adams clasps, creating complex multi-angled bends of starburst clasps, and preforming archwires with convenient slots.
Special attention should be given to third-order bends. To create torque rotation in the area of a single bracket, torque-bending pliers are used. It is important to understand that the pliers themselves only function to rigidly fix the wire, whereas the actual rotation is performed by an additional key.
For intraoral use, a tubular instrument is intended for bending distal end fragments of archwires, which is necessary for dental arch consolidation. Various cutters (converging sharply sharpened blades) are also used for working with wire, which are divided into distal angled cutters (with a pad to hold the cut-off fragment), telescopic cutters (for extra-hard facebow wires), and standard cutters.
Ligation and Working with Elastic Elements
Specialized clamps and ligators are used to fix the elements of the bracket system. Wire ligatures are tied using mosquito-type clamps or telescopic clamps. The latter allow forming the first turn snugly against the bracket, ensuring a firm fixation and saving the physician's time. If it is required to connect several brackets into a block with a long wire, a ligator with a fork-shaped branch and spool is used.
Elastic ligatures are fixed in several ways. The most common is the use of clamps with symmetrical recesses or hooks for securely holding the ring-shaped ligature. An alternative method involves using an instrument with a U-shaped working part: the ligature is stretched and transferred behind the bracket wings with a rotational movement. To remove elastics, an instrument with a spirally curved tip is used, allowing removed elements to be threaded onto it.
Debonding and Adhesive Removal Instruments
The removal of adhesive-fixed elements (debonding) requires care not to damage the enamel. For labial brackets, straight (for the anterior segment) or curved (for the lateral segments) pliers with a comb-like working part are used. There are modifications with paired bifurcated beaks for removing brackets along with the archwire, as well as ergonomic pistol pliers.
For lingual appliances, pliers with an extended angulated part or telescopic instruments with a spring mechanism are used. The removal of band rings is carried out either with knocking-out pliers (creating opposing pressure) or cutting pliers (fragmenting the ring wall). Remnants of the fixing material are preliminarily peeled off with special adhesive removal cleaning pliers, consisting of a scraper beak and a supporting beak with a plastic pad.
Rotary Instruments: Purpose and Classification
Rotary instruments are used for high-speed preparation of hard tissues of the maxillofacial region and the correction of dental structures. Any such instrument consists of a shank (for securing in the handpiece) and a working part.
According to the international ISO system, instruments are classified by 5 key criteria:
- Material type of the working part.
- Length and type of the shank.
- Shape of the working part.
- Abrasiveness or type of flute cutting.
- Maximum diameter.
| Type | Main Purpose |
|---|---|
| Bur | Preparation of hard tooth tissues |
| Cutter | Planar preparation, cutting |
| Disc | Separation, planar preparation |
| Abrasive | Preliminary processing |
| Polisher | Finishing processing |
Materials of Rotary Instrument Working Parts
The coating of the working part determines the properties and field of application of the instrument:
- Diamond grit: fixed to a steel blank by a metal bond (by electroplating or sintering). Electroplated deposition ensures uniform grain embedding, reducing heat generation. The sintering method (with iron or bronze alloys) is used for dental laboratory instruments. Some turbo instruments have spiral or diamond-shaped grooves for water cooling.
- Ruby chips (finishers): used for processing plastics. The main advantage is the absence of surface heating, which prevents prosthesis deformation.
- Tungsten carbide materials: burs and cutters made of tungsten carbide and cobalt are created by powder metallurgy. Computerized diamond cutting guarantees ideal blade symmetry. Solid tungsten carbide (maximum strength) and combined (on a steel base, cheaper) instruments are distinguished.
Briefly: answers to topical questions
What cross-section do ProFile system instruments have?
ProFile system instruments have a complex U-shaped cross-sectional shape.
The cross-sectional shape determines the type of endodontic instrument. For quick identification, the instrument is marked with a corresponding geometric figure on the end of the handle. Unlike ProFile files, other instruments have different cross-sectional shapes:
- Reamer (K-Reamer) — triangular cross-section.
- File (K-File) — quadrangular cross-section.
- Flexible file (K-Flexfile) — rhombic cross-section.
- Hedstrom file (Hedstrom) — round cross-section.
What taper do ProFile system endodontic files have?
ProFile system endodontic files have an increased taper of 4, 6, 8, 10, and 12%.
Unlike basic instruments, which most often have a 2% (0.02) taper, files with increased taper have a number of features:
- Designed for use in an endodontic handpiece.
- Used in a rotating clockwise mode.
- The recommended rotation speed is 150–350 rpm.
- For visual identification, the shanks of such instruments have a gold-plated coating.
What else to study on this topic
- Features of the application of distal angled cutters and telescopic instruments
- Structure and operating principle of thermoactive archwires and instruments with a cold element
- Protocol for working with convertible buccal tubes
- Technique of applying a ligature director when crossing wire ligatures
- Differences between single-sided, double-sided, peripheral, and continuous diamond disc coatings
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Other topics in «Chapter 3. Dental Instruments»
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.