Efficiency of early and late Class II Division 1 treatment.

The aim of this study was to assess the efficiency of early and late Class II Division 1 treatment in the mixed and permanent dentition. Treatment efficiency was defined as a better result in a shorter treatment time. We examined 204 patients with Class II Division 1 malocclusions treated in the early mixed dentition (n = 54), late mixed dentition (n = 104), and permanent dentition (n = 46). The pretreatment and posttreatment dental casts were evaluated with the peer assessment rating (PAR) index. The duration of treatment decreased with progressing dental development: patients in the early mixed dentition (dental stage [DS] 2) were treated for 57 months, patients in the late mixed dentition (DS 3) for 33 months, and patients in the permanent dentition (DS 4) for 21 months. Patients treated exclusively with fixed appliances had a shorter treatment duration (19 months for Herbst and 24 months for multibracket) than did patients treated with functional appliances or a combination of appliances (38 months for functional appliances and 49 months for a combination). The PAR score reduction (improvement) increased with progressing dental development: DS 2 patients had a PAR score reduction of 64%, DS 3 patients had a reduction of 73%, and DS 4 patients had a reduction of 77%. Patients treated exclusively with fixed appliances had a greater PAR score reduction (77%) than did patients treated with functional appliances or a combination (60% for fixed appliances and 71% for functional or a combination). Based on the results of this investigation, we concluded that treatment of Class II Division 1 malocclusions is more efficient in the permanent dentition (late treatment) than it is in the mixed dentition (early treatment).