Effects of two-phase treatment with functional appliances versus one-phase treatment with pre-molar extraction in Class II div 1 monozygotic twins: A case study

The aim of the study was to compare the skeletal, dental, or soft-tissue outcomes of a one-phase camouflage treatment with pre-molar extraction versus a two-phase treatment with combined twin-block high-pull headgear followed by fixed orthodontic treatment in monozygotic twins. 12-year-old male monozygotic twins presented to the dental clinic with complaints about their anterior teeth. Cephalometric analysis of the patients revealed skeletal Class II malocclusion and a long facial type. Extraoral examination of the patients revealed incompetence of lip seal and a convex profile. In Patient 1, the use of a high pull headgear combined with a twin block to correct skeletal anteroposterior and vertical malocclusions with growth modification and then fixed orthodontic treatment was planned. Patient 2 did not comply with the treatment, complaining that the use of the device could cause esthetic problems and difficulties in use. Therefore, camouflage treatment with extraction of four pre-molars was planned as another treatment option for Class II patients in Patient 2. With the camouflage treatment, the patient continued to grow normally. The combined treatment with twin block and a high pull occipital headgear resulted in inhibition of maxillary growth and a reduction in the severity of the skeletal Class II malocclusion, but the mandibular changes were similar in both patients at the end of treatment. Despite the different treatment modalities, both twins achieved a Class I canine-molar relationship and ideal overjet and overbite. Patients can close their lips with improved soft-tissue profiles. The criteria for the choice of treatment depend entirely on the requirements of the patient.