Comparison of the anterior alveolar bony changes of moderately crowded cases treated either with extraction or non-extraction orthodontic treatment

Extraction vs. non-extraction treatment in orthodontics has been debated for many decades. The alveolar bone surrounding the anterior permanent teeth should be a factor in making this decision. This article examines two separate studies that measured bony changes following orthodontic treatment in moderately crowded cases. A total of 59 cases (39 non-extraction and 20 four premolar extraction) were examined using CBCT, 2-D extraoral radiographs, and orthodontic models. The heights and thicknesses of the anterior bony support were measured on both the facial and lingual surfaces in extraction and non-extraction cases with the changes compared between the groups. Results showed that both treatment modalities experienced statistically significant bone loss with the lingual surfaces, which received the greatest and most consistent changes from orthodontic treatment. There were no statistically significant locations that showed a positive bony change. The pattern of bone loss from treatment was very similar for extraction and non-extraction cases with the non-extraction cases, on average, having a greater amount of bone loss.