To analyze mandibular advancement between the traditional Twin Block and the Angel Aligner A6 mandibular advancement clear aligners using cephalometric analysis in growing patients and a repeatable and reproducible digital measurement technique.
This study compared three early orthodontic treatments for Class II division 1 malocclusion in 60 growing patients (mean age: 12.4 ± 1.3 years): Twin Block, standard Angel Aligner, and Angel Aligner A6 with mandibular advancement. After 10 months, both Twin Block and A6 showed greater skeletal correction and mandibular advancement than standard aligners, achieving higher rates of Class I correction. The A6 group also had the shortest overall treatment time. Cephalometric analyses were performed using a digital and reproducible measurement technique. For each patient, lateral cephalograms were taken before treatment (T0) and after treatment (T1, after the functional phase or aligner completion). Thus, a total of 120 lateral cephalograms were analysed. The following skeletal, dental, and soft tissue parameters were analysed.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
60
Mandibular advancement with aligners is achieved using specially designed orthodontic aligners that incorporate built-in mandibular advancement features. These appliances posture the lower jaw forward in a controlled and incremental manner while simultaneously aligning the teeth. The forward positioning of the mandible helps stimulate mandibular growth in growing patients and improves the correction of Class II malocclusion by enhancing sagittal jaw relationship. Aligner replacement was performed at 10-day intervals.
The Twin Block is a removable functional orthodontic appliance used to correct Class II malocclusion by advancing the mandible. It consists of upper and lower acrylic plates with bite blocks that interlock at a specific angle, guiding the lower jaw forward during closure. It is most effective in growing patients to improve jaw relationship and facial profile. The Twin Block appliance, used for mandibular advancement (correction of skeletal class II), was usually worn for a period of 10 months, with a minimum of 14-16 hours per day, including night hours.
University of Salamanca
Salamanca, Salamanca, Spain
ANB (°)
Point A-nasion-point B angle (ANB): relationship between the upper and lower jaws
Time frame: 10 months
Wits appraisal (AO-BO)
projecting points A and B in two perpendicular lines, along the functional occlusal plane
Time frame: 10 months
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Class II correction with aligners (without mandibular advancement) involves the use of clear sequential aligners to improve dental alignment and occlusion by moving teeth into a more favorable position. The correction is achieved through controlled tooth movements such as distalization, interproximal reduction, and vertical control, without actively repositioning the mandible forward.