{"id":3430,"date":"2008-11-18T15:46:00","date_gmt":"2008-11-18T14:46:00","guid":{"rendered":"https:\/\/www.zerodonto.com\/en\/2008\/11\/micro-screws-in-orthodontics-clinical-problems\/"},"modified":"2017-11-28T12:19:21","modified_gmt":"2017-11-28T11:19:21","slug":"micro-screws-in-orthodontics-clinical-problems","status":"publish","type":"post","link":"https:\/\/www.zerodonto.com\/en\/2008\/11\/micro-screws-in-orthodontics-clinical-problems\/","title":{"rendered":"Micro-screws in Orthodontics \u2013 clinical problems"},"content":{"rendered":"

\u00a0<\/span><\/p>\n

The use of micro-screws in orthodontic anchorage is becoming more and more frequent in both vestibular and lingual techniques with brackets, and in more aesthetic and comfortable techniques without brackets.<\/p>\n

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Micro-screw insertion should be considered a surgical procedure as erroneous handling of the bone can easily lead to <\/span>an inflammatory reaction around the screws and incorrect positioning can lead to their <\/span>loosening.<\/span><\/p>\n

Thus, in an attempt to make things clearer and to answer questions we have been asked by many of our colleagues, we can make a list of the problems that can be encountered and also share our experience in solving them. <\/span><\/p>\n

The main problems which we can encounter when inserting a micro-screw are:<\/span><\/p>\n

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  1. Premature loosening of the micro-screw;<\/span><\/li>\n
  2. An inflammatory reaction around the micro-screw with subsequent expulsion of the latter and the simultaneous loss of a small quantity of bone mass around the micro-screw;<\/span><\/li>\n
  3. Micro-screw breakage<\/span>;<\/span><\/li>\n
  4. Periodontal damage when we \u201ctouch\u201d the dental element with the micro-screw;<\/span><\/li>\n
  5. Damage to anatomical structures close to the insertion site (vascular, neural and maxillary sinus); <\/span><\/li>\n
  6. Decubitus ulcer on the alveolar mucosa and buccal mucosa, which often develops, above all, in the inferior dental arch.<\/span><\/li>\n<\/ol>\n

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    1. Screw loosening<\/span><\/h3>\n

    It is important to make some comments on this topic.<\/p>\n

    Nowadays, one can find osteointegrable micro-screws with a rough surface. After insertion of the screws, one must wait for osteointegration to occur before loading them. They are more difficult to remove. <\/span><\/p>\n

    Micro-screws with a smooth surface also exist, and these are mostly used by orthodontists. These screws do not osteointegrate and they become anchored to the bone through friction.<\/span><\/p>\n

    Let us begin by recounting something which is only the fruit of our experience. While it is true that in implantology the conical-shaped screw allows for a greater primary stability and thus an increased certainty of osteointegration, the same cannot be said for smooth, non-osteointegrable micro-screws. The smooth micro-screw is anchored via the friction that it has with the bone.<\/span><\/p>\n

    If we use a conical micro-screw, it can become completely unscrewed <\/span>if turned just half way anticlockwise. On the other hand, a cylindrical micro-screw continues to rub along its path without losing stability even if it becomes slightly unscrewed. Thus, judging from our experience, the conical, non-osteointegrable screws should not be used. <\/span><\/p>\n

    Furthermore, if elastic bands are used, it is important to fasten them to the head with some composite fluid in order to prevent micro-screw loosening. This is because band oscillations, which can be produced when the patient speaks or eats, are transmitted to the micro-screw thereby loosening it. Infact, an oscillation of the band transmits a force to the micro-screw in a clockwise direction, and moments later another force in an anti-clockwise direction. As the force in the anti-clockwise direction is set against a lesser friction of the micro-screw, the screw tends to loosen. In order to prevent this from occurring, it is sufficient to fix the elastic band to the micro-screw using some fluid composite which keeps it in place.<\/span><\/p>\n

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    In order to prevent micro-screw loosening, we recommend avoiding immediate loading. One should wait at least one week in order to allow optimal tissue integration of the screws. <\/span><\/p>\n

    2.<\/span> Inflammatory reaction<\/span><\/h3>\n

    There are two reasons why an inflammatory reaction may occur around the micro-screw.<\/span><\/p>\n

    If the reaction is immediate, it may be due to incorrect handing of the bone tissue or contamination of the surgical site.<\/span><\/p>\n

    If the reaction occurs later on, it may be due to micro movements of the micro-screw within the bone which trigger a foreign body response and seizure of the screw. <\/span><\/p>\n

    Only titanium and never stainless steel micro-screws should be employed due to titanium\u2019s properties and its biocompatibility.<\/span><\/p>\n

    \"P1000300\"<\/a><\/p>\n

    We use the following standard operating procedure: <\/span><\/p>\n