Parapulular pin

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Parapulular pen,
on the right a 2-in-1 pen ,
greatly enlarged
Amalgam filling with parapular stick

A parapulpal pin (or screw ) is used in dentistry as a retention aid . Parapulular pins are made of titanium or non-corrosive base metals and may be gold-plated . Depending on the manufacturer, they have a diameter of around 0.5 mm and a total length (without shaft) of around 4 to 6 mm. They serve to anchor plastic filling materials ( amalgam , composites ) or core build- ups in the dentin .

Attachment

The post is attached by first drilling a fine channel (approx. 2.5 mm deep) with a pre-drill at very low speed (see: contra-angle handpiece ), which has a minimally smaller diameter than the parapulpic post, into the dentin. The pen has a self-tapping thread ( Thread Mate System (TMS) or also: Thread Made System ) and thus finds a good grip when screwing in (also at a very low speed or manually with a small, handy instrument). On the half of the pen there is a thickening that acts as a stop and prevents the pen from penetrating deeper. Towards the shaft there is a predetermined breaking point at which the screwed-in pin detaches from the shaft as soon as the stop reaches the dentine. An attachment in the tooth enamel is not possible because it is too brittle.

The dental trade supplies pens of various sizes. In addition to the regular pens, there are also smaller minikin pens and so-called 2-in-1 pens , in which two pens are mounted one behind the other on a shaft, which can be screwed in one after the other. In any case, it must be ensured that the pre-drill and pin are matched to one another, i.e. belong to the same set . Color markings are helpful here.

indication

The use of parapulular posts is advisable if one or more additional retentions are required when building up a tooth with a plastic filling material in order to achieve adequate fixation and stabilization. While parapulpular posts are well suited for anchoring amalgam fillings , the use of visible anterior fillings with tooth-colored, very transparent composites is often problematic because the metal post can shimmer through. If necessary, the post can be covered with an opaque layer . But that is very time-consuming.

Risks

  • If parapulular pins are used in close proximity to the pulp (pulp), iatrogenic perforations (caused by the treatment) can occur and the pulp can be damaged.
  • If a Parapulpärer pin in the tooth neck region used, it may be due to the fact the tooth that in this area greatly narrows to a perforation in the gap between the tooth root and bone ( periodontal membrane ) may occur, to a (locally restricted) gingivitis ( periodontitis ) can lead.
  • The filling material can break (crumble) if the layer of filling material covering the pin is not sufficiently thick and the pin looks like a wedge.
  • Microcracks and tension in the dentin can lead to pain sensations. (Rarely).
  • A break in the pre-drill in the dentine or a break in the post at a point other than the predetermined breaking point is harmless and does not require any further treatment.

Individual evidence

  1. ↑ para: (from ancient Greek : πᾶρἆ (para) 'at', 'next to') Wilhelm Gemoll : GEMOLL, Greek-German school and manual dictionary , G. Freytag Verlag, Munich.
  2. ↑ pulpär: (from Latin : pulpa 'meat') Joseph Maria Stowasser : Der Kleine Stowasser , Latin-German school dictionary , G. Freytag Verlag, Munich.

Source / literature

See also