Читать книгу Orthodontic Treatment of Impacted Teeth - Adrian Becker - Страница 34

An eyelet, welded to orthodontic bond material with a mesh backing (Figure 2.4), is soft and easy to contour, enabling its adaptation to the bonding surface to be more intimate and retentive. Its relatively small size and low profile make the mid‐buccal position of several of the more awkwardly placed teeth considerably more accessible as compared with the placing of a conventional bracket. Its modest dimensions are also less of an irritant to the surrounding tissues, particularly during the critical phase as it breaks through gingival tissues in the final stages of its eruption into the oral cavity [15].

Fig. 2.4 Eyelets welded to a pliable band material base, backed by steel mesh.

The need to properly adapt the base of the attachment to the shape of the recipient surface of the crown of the tooth cannot be over‐emphasized. Thus, the use of standard brackets with ‘anatomic’ bases, as supplied by the manufacturer, has been shown [14] to fare considerably better in the mid‐buccal position of the impacted tooth (80.6%) than on any other surface, particularly the palatal surface. The chances of the survival on a palatal site were shown to be 58.3% – i.e. a failure rate of almost 1 in 2. By comparison, a small attachment (such as an eyelet) on a pliable base, properly and individually adapted to the form of the recipient site, which demonstrated a 96.7% level of reliability against detachment, will allow the orthodontist to work with the greatest degree of confidence.

A button is useful for engaging elastic chains and is usually placed on the lingual side of a tooth in circumstances where rotation of the tooth is required. However, it is also suitable in the present context.

For these reasons, small eyelets and buttons are recommended as the initial attachment, which is placed at the time of surgery and removed only when the tooth has progressed to the point where it is in close proximity to the archwire. At that point in time, they should be replaced by the same type of sophisticated bracket that is being used on the other teeth, thereby initiating the more intricate root manipulations of the tooth (rotating, uprighting and torqueing). Also at this point, the impaction will have been treated and there will be no ectopically displaced teeth. All the teeth will be located close to the line of the arches, forming what would otherwise constitute a typical pre‐orthodontic scenario. Elsewhere in this book I have called this environment the ‘orthodontic ballpark’, because the case will have now become a routine orthodontic case.