[Effect of two stage corticotomy on maxillary protraction].

For the purpose of clarifying the effects of two stage corticotomy on maxillary protraction, experimental studies by using of 5 male Japanese monkeys (Macaca fuscata) were performed. Results from cast analysis, roentgenographic cephalometry and histological examinations were as follows. I. In experimental groups that received two stage corticotomy with maxillary protraction, apical base of maxillary bone protruded markedly. II. In control groups that maxillary protraction was applied without corticotomy, sutured area around maxilla seemed to be influenced by orthopedic force. However, hardly any influence from orthopedic force was seen in experimental groups. III. In both groups individual teeth of upper dental arch hardly moved. IV. After two stage corticotomy, no circulatory disturbance in maxillary bone except for reactive inflammation of pulp in anterior teeth and vacuolar degeneration in anterior teeth and posterior teeth was seen, and periodontal tissue remained almost unaffected. This suggested that corticotomy should be performed carefully, especially in anterior apical base of maxillary bone.