Orthodontists make every possible effort to create full smiles, and non-extraction treatments are becoming increasingly popular among patients. However, dental arch dimensional changes tend to relapse, and this instability is one of the main reasons why non-extraction treatment remains an open question. Key factors guiding the choice between extraction and non-extraction are the amount of crowding and aesthetic concerns, and non-extraction treatment is therefore often indicated in patients with moderate, and sometimes severe, crowding who could benefit from increased lip support.
This presentation focuses on the rationale for non-extraction treatment and its long-term stability. We compared data from dental casts and lateral cephalograms of patients consecutively treated with a trans-palatal arch in the upper arch and a lip bumper in the lower arch during the mixed dentition stage followed by fixed appliances in the permanent dentition with those of an untreated matched control sample, both during treatment and at long-term follow-up. Arch widths, perimeters, and lengths as well as crowding and incisor proclination were evaluated. In the treated group, upper and lower dimensional changes improved significantly after treatment with trans-palatal arch and lip bumper before the application of braces, whereas only minor increases were recorded after fixed appliance treatment. At long-term follow-up, all the arch widths were slightly decreased, with a 0.4 millimeter increase in crowding, considered clinically irrelevant. However, overall dental arch changes remained stable. The best predictors of relapse and long-term stability were also evaluated.
