Change in clinical crown height in adult patients treated by means of the multi-bracket appliance with extraction of four first premolars

Abstract

Objective:

To evaluate the gingival condition due to adult orthodontic treatment using the clinical crown height (CCH) as an index.

Design:

Retrospective study.

Setting:

Department of Orthodontics at a university.

Participants:

A total of 21 adult female patients with healthy periodontal tissue were treated by means of the multi-bracket appliance with extraction of four first premolars.

Methods:

Three-dimensional (3D) digital dental models were reconstructed to assess the vertical movement of the free gingival margin caused by adult orthodontic treatment. Pre- and post-treatment CCH were measured, and changes in CCH due to treatment were examined.

Results:

The change in CCH by orthodontic treatment was able to be assessed objectively using 3D digital models of the dental casts. In the upper dentition, a significant reduction in CCH was found on the labial and lingual sides of the central incisor, with a mean of –0.28 mm and –0.34 mm, respectively (P < 0.001). In contrast, a significant increase in CCH was found on the labial side of the lateral incisor with a mean of 0.75 mm (P < 0.001). In the lower dentition, CCH on the lingual side of the canine, the second premolar and the first molar increased significantly (P < 0.001), with a mean of 0.41 mm, 0.45 mm and 0.50 mm, respectively. For the buccal side, the second premolar showed a significant increase in CCH with a mean of 0.61 mm (P < 0.001).

Conclusion:

By using the CCH as an index, it was possible to assess the gingival condition after active orthodontic treatment.