Summary In the overall analysis, the response to Phase I treatment was excellent. The patient was treated on a nonextraction basis. There was a short second phase of treatment because of the excellent results achieved with the first phase of orthodontic treatment. The aim of mixed-dentition treatment at the University of the Pacific Orthodontic Department is to establish an ideal result in Phase I therapy and to maintain this result during the supervision period. The second phase can be eliminated, or the extent of Phase II treatment can be significantly reduced.