An interventional study of Upper molar distalization in Distalization, Class II Malocclusion and Aligner Therapy, sponsored by Aristotle University Of Thessaloniki. Recruiting at 1 site in Greece. Open to participants aged Up to 30 Years. Per ClinicalTrials.gov, last updated 2025-06-27.
Sponsored by Aristotle University Of Thessaloniki · Not applicable, Interventional, and Treatment
The goal of this randomized clinical trial is to compare distalization of maxillary first and second molars achieved with a device supported with mini screw implants in the palate (Advanced Molar Distalization Appliance, AMDA®) with distalization of maxillary first and second molars achieved with clear aligners (Spark®) supported by Class II elastics.
The main questions it aims to answer are:
Is there any difference in achieving upper molar distalization with the Advanced Molar Distalization Appliance (AMDA®) supported by miniscrew implants and with clear aligners (Spark®) supported by Class II elastics at the end of active distalization phase?
Is there any difference between the two groups in the anchorage loss at the end of total treatment?
Additionally, the differences in the movements of premolars, canines and incisors will be analyzed in all three planes of space (sagittal, transverse, vertical), as well as the duration of treatment between the two groups and subgroup comparisons will be performed regarding age, gender, presence of maxillary third molars and severity of malocclusion.
Participants will be randomly assigned to the AMDA® or Spark® group. Treatment will take place at the Department of Orthodontics and participants will have to visit the clinic every 4-6 weeks for regular check ups. Intraoral scans, photographs and x-rays (panoramic x-ray, cephalometric x-rays) will be taken before treatment, at the end of active distalization phase and at the end of treatment.
The aim of the study is to compare distalization of maxillary first and second molars achieved with the Advanced Molar Distalization Appliance (AMDA®) supported by miniscrew implants with distalization of maxillary first and second molars achieved with clear aligners (Spark®) supported by Class II elastics. All patients will be randomly assigned into two groups:
Lateral cephalometric radiographs of the patients' heads and three-dimensional (3D) intraoral scans of the maxillary and mandibular arches will be taken:
Cone Beam Computed Tomography (CBCT) dental scans will be taken in patients assigned to the AMDA group:
Completion of orthodontic treatment of all patients will be accomplished when Class I molar and canine relationships, normal overjet and overbite, a good leveling and alignment of the teeth, and a tight occlusion of the posterior teeth will be achieved.
In all these three time points the corresponding 2D and 3D analysis will include:
All patients will be treated in the Postgraduate Clinic of the Department of Orthodontics at the Aristotle University of Thessaloniki by the applicant (Mrs. Samandara) under the supervision of Professor Papadopoulos. Assistance will be provided by the postgraduate students after insertion of the appliance, during the follow up appointments for checking and re-activating the appliances.
Exclusion Criteria:
The AMDA arm consists of patients that will be treated initially for molar distalization with a miniscrew implant supported device (AMDA®) and for anterior teeth retraction (after molar distalization) with the same device and fixed appliances. The miniscrew implants will be inserted in the anterior region of the palate, especially 6-9 mm posterior to the incisive foramen and 3-6 mm paramedian.
Procedure: Upper molar distalization
The Spark® arm consists of patients that will be treated with clear aligners and elastics for both molar distalization and anterior teeth retraction.
Procedure: Upper molar distalization
This study aims to compare upper molar distalization movement achieved with a non-compliance miniscrew implant supported appliance (AMDA®) with distalization of upper molars achieved with clear aligners (Spark®) supported by Class II elastics.
Linear measurements for anteroposterior changes of maxillary first molar distalization movement at the end of active distalization (until Class I molar relationship is achieved).
Cephalometric analysis performed in lateral x-rays and cast analysis performed in intraoral scans will provide us with linear measurements assessing the anteroposterior movement of maxillary first molars.
Time frame: T1: Baseline records (initial records before the beginning of treatment). T2: 8-12 months, end of distalization phase records (records taken at the end of upper molar distalization, when upper first molars will be bilaterally in Class I malocclusion).
Linear measurements for anteroposterior changes of maxillary first molar distalization movement at the end of total orthodontic treatment.
Cephalometric analysis performed in lateral x-rays and cast analysis performed in intraoral scans will provide us with linear measurements assessing the anteroposterior movement of maxillary first molars at the end of orthodontic treatment.
Time frame: T1: Baseline records, (initial records before the beginning of treatment). T3: End of treatment records (records taken at the end of orthodontic treatment after removal of all orthodontic appliances), an average of 24 months.
Angular measurements for anteroposterior changes of maxillary first molar distalization movement at the end of active distalization (until Class I molar relationship is achieved).
Cephalometric analysis performed in lateral x-rays will provide us with angular measurements assessing the anteroposterior movement of maxillary first molars.
Time frame: T1: Baseline records (initial records before the beginning of treatment). T2: 8-12 months, end of distalization phase records (records taken at the end of upper molar distalization, when upper first molars will be bilaterally in Class I malocclusion).
Angular measurements for anteroposterior changes of maxillary first molar distalization movement at the end of total orthodontic treatment.
Cephalometric analysis performed in lateral x-rays will provide us with angular measurements assessing the anteroposterior movement of maxillary first molars at the end of orthodontic treatment.
Time frame: T1: Baseline records, (initial records before the beginning of treatment). T3: End of treatment records (records taken at the end of orthodontic treatment after removal of all orthodontic appliances), an average of 24 months.
Duration of active distalization phase
Comparison of the duration of active distalization between the two approaches (AMDA® and Spark®).
Time frame: T1: Baseline records (initial records before the beginning of treatment). T2: 8-12 months, at the end of distalization phase (records taken at the end of upper molar distalization, when upper first molars will be bilaterally in Class I malocclusion).
Duration of total treatment
Comparison of the duration of total treatment between the two approaches (AMDA® and Spark®).
Time frame: T1: Baseline records, (initial records before the beginning of treatment). T3: End of treatment records (records taken at the end of orthodontic treatment after removal of all orthodontic appliances), an average of 24 months.
Plan to share: Yes — All collected IPD (Study Protocol, Statistical Analysis Plan (SAP), Informed Consent Form (ICF), Clinical Study Report (CSR), Analytic Code will be shared.
Supporting information: Study protocol, Sap, Icf, Csr, Analytic code
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Aristotle University Of Thessaloniki