An interventional study of Infrazygomatic Crest Miniscrews in Class II Malocclusion, sponsored by Mansoura University. Recruiting at 1 site in Egypt. Open to participants aged 15 Years to 30 Years. Per ClinicalTrials.gov, last updated 2026-10-20.
Sponsored by Mansoura University · Not applicable, Interventional, and Treatment
This prospective clinical study will evaluate the effects of moving the entire upper dental arch backward using infrazygomatic crest miniscrews in participants with Class II malocclusion.
Class II malocclusion is a type of bite problem in which the upper and lower teeth do not have a normal front-to-back relationship. Infrazygomatic crest miniscrews provide temporary skeletal anchorage that can be used to move the upper teeth backward while reducing dependence on patient cooperation.
Participants will receive orthodontic treatment using bilateral infrazygomatic crest miniscrews connected to the upper orthodontic archwire through power arms and elastomeric chains. Changes produced by treatment will be evaluated using clinical photographs, radiographs, and digital dental models obtained before distalization and after correction of the Class II molar relationship.
The study will assess dental, skeletal, soft-tissue, and maxillary arch changes associated with this treatment approach.
Class II malocclusion is commonly treated by distal movement of the maxillary dentition when appropriate. Conventional distalization approaches may depend on patient cooperation and may have limitations related to anchorage control. Temporary skeletal anchorage devices, including orthodontic miniscrews, provide a source of anchorage that can reduce dependence on patient compliance.
The infrazygomatic crest is located superior and lateral to the maxillary molar region. Placement of miniscrews in this extra-alveolar region allows orthodontic tooth movement with less interference between the miniscrews and the roots of the teeth during distalization.
In this prospective clinical study, en-masse distalization of the maxillary dental arch will be performed using bilateral infrazygomatic crest miniscrews. After orthodontic leveling and alignment, 6-mm power arms will be positioned between the maxillary lateral incisors and canines bilaterally. Elastomeric chains will connect the power arms to the infrazygomatic crest miniscrews to produce distalizing forces.
Study records will be obtained at two time points: before treatment (T1) and after correction of the Class II molar relationship (T2). Records will include extraoral and intraoral photographs, lateral cephalometric and panoramic radiographs, and digital dental models.
Cephalometric evaluation will be used to assess skeletal, dental, and soft-tissue changes. Digital dental models will be used to assess changes in maxillary arch dimensions, including arch length, arch perimeter, and transverse dental arch widths. Pre-treatment and post-distalization measurements will be compared to evaluate the effects of total maxillary arch distalization using infrazygomatic crest miniscrews.
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Exclusion Criteria:
Participants with Class II malocclusion will undergo en-masse maxillary arch distalization using bilateral infrazygomatic crest miniscrews. Two miniscrews measuring 2 mm in diameter and 12 mm in length will be used. Six-millimeter power arms will be placed bilaterally between the maxillary lateral incisor and canine. Closed elastomeric power chains will connect the miniscrews to the archwire hooks, applying approximately 350 g of distalizing force.
Device: Infrazygomatic Crest Miniscrews
Two bilateral infrazygomatic crest miniscrews (Ortho Central, Korea), 2 mm in diameter and 12 mm in length, will be used as skeletal anchorage for en-masse maxillary arch distalization. The miniscrews will be inserted in the infrazygomatic crest region, commonly between the maxillary first and second molars, approximately 11 mm above the occlusal plane. Six-millimeter power arms will be placed bilaterally between the maxillary lateral incisor and canine. Closed elastomeric power chains will connect the miniscrews to the archwire hooks, applying approximately 350 g of distalizing force.
Change in Sagittal Position of the Maxillary First Molar (U6 Crown to Y-Axis)
The sagittal position of the maxillary first molar will be assessed on lateral cephalometric radiographs by measuring the linear distance, in millimeters, from the mesiobuccal crown of the maxillary first molar (U6) to the Y-axis. The Y-axis is defined as a vertical reference line perpendicular to the X-axis and passing through Sella. Change between T1 and T2 will be used to quantify maxillary first molar distalization.
Time frame: Baseline (T1) and six months after treatment initiation (T2), following correction of the Class II molar relationship.
Plan to share: No — Individual participant data will not be shared. The study protocol does not include a plan for sharing participant-level data, and data will be kept confidential in accordance with institutional and ethical requirements.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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