|Keywords:||Dentistry; Bone Anchored Expansion; CBCT; Expansion; MARPE; Mini Implants|
|Full text PDF:||http://www.escholarship.org/uc/item/88x5s9xq|
Objective:The aim of this clinical pilot study is to see if a novel mini-implant assisted rapid palatal expander (MARPE) has similar dental and skeletal treatment effects in an Early Treatment Group (ETG) and a Late Treatment Group (LTG) through the use of Cone Beam Computed Tomography (CBCT) analysis. Methods:Orthodontic patients requiring MARPE were asked to participate in a clinical study. A pilot study consisting of ten patients were grouped into an ETG or LTG according to their Cervical Vertebral Maturation Stage (CVMS). Five patients with CVMS stage 1-4 were placed in the ETG, and 5 patients with CVMS stage 5 were placed in the LTG. CBCTs were taken for initial records (T0), immediately after expansion (T1), and 6 months after expansion was complete (T2). Skeletal versus dental effects, and palatal volume were measured between T0, T1 and T2, and between groups, using Dolphin Imaging and itk-SNAP.Results:Similar results were seen between groups for all the skeletal outcomes except at NW, BBW, TDTZ from T1-T0, Basal Bone Width and Buccal bone width at 14mm from T2-T1, and MW, and TDTZ from T2-T0, where these measures showed statistical significance between groups. The ratio of mid-palatal suture opening at M1 and expansion width in the appliance at T1, was 69% in the ETG and 34% in the LTG. There was 6° of dental tipping in the LTG, and 1° of tooth uprighting in the ETG after expansion. Buccal bone width at both 11 and 14 mm decreased during expansion, and then increased during the retention phase in both groups. Palatal volume increased following expansion, with a slight decrease during the retention phase. In the ETG there was 61% skeletal expansion, 10% bone bending and 29% dental tipping, compared to 34% skeletal expansion, 4% bone bending, and 62% dental tipping in the LTG.Conclusion:The use of a novel MARPE has overcome the limitations of a traditional tooth-anchored appliance, allowing force to be directed adjacent to the mid-palatal suture, opening up the suture and achieving true skeletal expansion in a late treatment group. This pilot study has shown significant differences in certain measures between the ETG and LTG, however increasing our sample size will determine if there is a true difference between groups.