Indian Board of Orthodontics Case Report: Management of a Skeletal Cl II Malocclusion Using Two-phase Treatment with a Standard Twin Block Appliance

Abstract

NK, a 12-year-old male patient, presented with a Class II division 1 incisor relation on a Class II skeletal base with a decreased maxillomandibular plane angle and decreased face-height ratio. He had a convex profile, incompetent lips, lip trap, deep mentolabial sulcus, everted lower lip and a positive VTO (Visual Treatment Objective). Intraorally, he presented with bilaterally Angle’s Class II molar relation and canine relation, scissor bite in the region of first premolars bilaterally, a closed bite and a 13 mm overjet. He presented with mild spacing in the upper arch and mild crowding in the lower arch with a pronounced curve of Spee. This was further complicated as the LR6 was endodontically treated and temporarily restored; also, enamel hypoplasia was seen in all permanent first molar region. The treatment was carried out in two phases, Phase I involved growth modulation done with a twin block appliance, and Phase II was the postfunctional orthodontic phase for dental corrections and finishing and detailing of occlusion, which was done with a preadjusted edgewise appliance (0.022 × 0.028˝ slot) with MBT (McLaughlin, Bennett, Trevisi) prescription. The posttreatment results were highly satisfactory, showing improvement in facial esthetics and occlusal traits as well as good long-term stability as was evident in the 3-year retention records.