Dental Problems

Fixed Space Maintainer – Band Formation

tooth-5Space maintainers may range from very simple to those complex ones with numerous wires and bands. In this article there is a brief discussion on the construction of the fixed space maintainer, technique for band construction and steps in band formation. Let us examine them.

Construction of space maintainer :
The fixed space maintainer generally is constituted of the following components:

  • a. Band
  • b. Loop or arch wire
  • c. Solder joint
  • d. Auxiliaries

Band:

The band forms an important part of the construction of the various fixed appliances. Several bands are employed such as:

  1. Loop bands:

    • a. Precious metal (first introduced by Johnson)
    • b. Chrome alloy bands
  2. Tailored bands:

    • a. Precious metal
    • b. Chrome alloy
  3. Performed seamless bands:
    • a. Chrome alloy or precious metal which are adopted, festooned and stretched to fit.

A range of performed bands from 1-32 depending on the mesiodistal width of the tooth for the maxillary and mandibular arch are available commercially.

Band material:

Depending on the tooth to be banded, they can be classified as:

  • Anterior teeth -0.003 by 0.125 by 2 inches
  • Bicuspids -0.004 by 0.150 by 2 inches
  • Molar region (deciduous) -0.005 by 0.180 by 2 inches
  • Molar region (permanent) -0.006 by 0.180 by 2 inches

Technique for band construction:

Every band should possess a few ideal criteria such that –

  • It should fit the contours of the tooth as closely as possible, thereby enhancing the placement of the attachment in relationship to the tooth.
  • Should not extend subgingivally any more than necessary.
  • Band material should resist deformation under stresses in the mouth.
  • Resist tarnish.
  • Inherent springiness.
  • Cause no occlusal interference.

Steps in band formation

  • A. Separation
  • B. Band fitting (band pinching)
  • C. Welding
  • D. Soldering
  • A. Separation:

    Adequate separation of the teeth is an essential prerequisite for any banding technique.

    Methods:

    • Brass wire -0.015 inch -0.020 -inch soft brass wire. It works well in young patients with thick periodontal membrane, but can be quite painful.
    • Elastic threads -These provide a gentle force over a prolonged period and are painless at the time of insertion.
  • B. Band formation:

    Various techniques of band formation are known. These can be:

    • a. Direct formation
    • b. Performed bands
    • c. Indirect band technique

    Direct formation of the band in the mouth involves:

    i. Band pinching:

    • The band strips are first contoured in an inciso -gingival or occluso -gingival direction using the Johnson’s contouring pliers. The ends of the strip of the band material are welded and then a loop is made for the reception of Howlett band forming pliers. This contoured strip is located on the tooth in the desired position.
    • The bands should be pinched on the cuspal area and not on the groove areas. This is because, it is difficult to adapt a double thickness of the band in the groove areas.
    • The upper molar band is usually pulled from the palatal side, whereas the lower molar band is pulled from buccal side.
    • The seam of the upper band will be kept at the mesiolingual line angle whereas for the lower, at the mesiobuccal line angle.
    • The two edges of the seam should be parallel to each other so that the band rests uniformly on the tooth surface.
    • In cases where a sufficient clinical crown is available, the peak band -forming plies may be employed on the teeth. These are available as right and left.

    ii. Festooning:

    • This constitutes the countouring of the band in order to follow the gingival margin proximally. The level of the band at the marginal ridge is also adjusted in the process.
    • The distal side may require more trimming because of the lower position of the marginal ridge as well as due to the raised position of the gingival (especially during eruption of the distal tooth).

    iii. Trimming:

    This involves reducing on the buccal and lingual side if required. This primarily adjusts the occluso-cervical length of the band.

    iv. Folded flap method:

    • After the formation of the seam, the excess is cut off, leaving a small remnant. The band is then returned to the tooth and the small remnant is folded neatly against the lingual surface of the tooth.
    • This should be done directly on the tooth: otherwise the band will be made smaller during the process of folding over the tag. The folded over remnant is then spot welded. The band may sometimes require crimping to produce a rolled retentive edge to the band.
    • The occlusal margins of a completely seated band should be slightly below the proximal ridges (1 mm).
    • Gingival margins should extend 0.5 to 1.0 mm into the gingival sulcus (Owen et al 1984). A better criterion is to check clinically for the blanching and relieve the areas where it is seen.
    • Buccally it should be just below the level where the opposing cusps touch the grooves.
    • Lingually, it should be placed just below the deepest portion of the lingual developmental groove.

    A partially indirect technique involves the construction of the bands and then taking impressions to form the appliance on the cast. A totally indirect technique is where the bands are also constructed on the cast. This is useful as it provides a more efficient and faster method.

  • C. Welding:

    Welding is the process during which a portion of the metal being joined is melted and flowed together. Bands are generally joined by welding. Electric spot welding is carried out with electric current being forced to flow through a limited area on the materials to be welded. The resistance of the materials to electric current generates an intense localized heat and brings about fusion of the two surfaces.

  • D. Soldering:

    It is the process by which the two metals are joined together by an intermediary metal of a lower fusion temperature. The most common solder used is the silver solder containing silver, zinc, copper and tin.

    Flux is used to increase the flow and prevent oxidation. The solder is applied to the joint after which finishing is done with a green stone, while polishing with a rouge.

The above article discusses about the fixed space maintainer.

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