Till Örebro universitet

OBJECTIVES: To evaluate and compare the skeletal and dentoalveolar effects of tooth-borne (TB) and tooth-bone-borne (TBB) rapid maxillary expansion (RME).

MATERIALS AND METHODS: Fifty-two consecutive patients who met the eligibility criteria were recruited and allocated to either the TB group, mean age 9.3 years [standard deviation (SD) 1.3], or the TBB group, mean age 9.5 years (SD 1.2). Cone-beam computed tomography (CBCT) records and plaster models were taken before (T0), directly after (T1), and 1 year after expansion (T2). Dentoalveolar and skeletal measurements were made on the CBCT images. The dental expansion was also measured on the plaster models.

RANDOMIZATION: Participants were randomly allocated in blocks of different sizes using the concealed allocation principle in a 1:1 ratio. The randomization list was also stratified by sex to ensure homogeneity between groups.

BLINDING: Due to clinical limitations, only the outcomes assessors were blinded to the groups to which the patients were allocated.

RESULTS: Skeletal expansion in the midpalatal suture and at the level of the nasal cavity was significantly higher in the TBB group. However, the magnitude of the expansion in the midpalatal suture was around 1 mm [95 per cent confidence interval (CI) 0.5-1.7, P = 0.001] more and perhaps not clinically significant. The magnitude of the expansion at the level of the nasal cavity was almost two times higher in the TBB group (95 per cent CI 0.7-2.6, P = 0.001). The dental expansion, alveolar bending, tipping of the molars, and stability 1 year post-expansion did not show any statistically significant differences between the groups. The actual direct cost of the treatment for the TBB group was approximately €300 higher than TB group.

LIMITATIONS: Double blinding was not possible due to the clinical limitations.

CONCLUSIONS: In young preadolescents with constricted maxilla and no signs of upper airway obstruction, it seems that conventional TB RME achieves the same clinical results with good stability 1 year post-expansion at lower cost.

TRIAL REGISTRATION: The trial was not registered.