What is a crown extension?
A crown extension is a dental-surgical measure. The visible part of the tooth, which protrudes from the bone into the oral cavity and is surrounded by the gums, we speak of the crown, is surgically “extended”. However, this is not an additive measure, i.e. something that is added, but on the contrary, an action in which something is removed in close proximity to the tooth. This paradox is what ultimately results in the “extension”.
Reasons for a crown extension
Depending on the findings (initial situation), it may be necessary to want or need to preserve a tooth, otherwise the next step, namely tooth extraction (pulling the tooth) will leave a gap. It is then difficult or unsatisfactory to provide the tooth with a dental prosthesis afterwards. For example, this may be the case with a tooth that has a deep hole (caries) near the alveolar process (bone crest).
Another example would be a tooth in which a part of the crown is so badly fractured (broken off) that the basic treatment of a filling can no longer be carried out correctly according to the rules of dentistry. There are two main reasons that play a major and important role in this case. Firstly, it would be the drainage and secondly, the lack of support for special measures during the placement of the filling, such as the application of a band or bulbed (curved) matrix (metal band to be applied around the tooth to restore the anatomical shape of the tooth).
It is necessary to perform absolute or relative drainage of the tooth. Absolute drainage is achieved by using and placing a so-called rubber dam (latex shield). In case of relative drainage it is necessary to exclude the rising liquid from the sulcus (upper gumline) by using cotton rolls.
Sometimes, however, there are limits to this due to the defect situation, i.e. the absence of parts of the tooth, for example if the tooth or defect ends at bone level. In this case, surgical removal of the jawbone can be used to allow parts of the tooth to protrude that were previously covered by the bone, thus creating a visual and measurable extension. This can then be used to dry the tooth with the help of a matrix in the required dry condition and with the necessary support for a matrix or crown preparation.
