LONGITUDINAL CHANGES IN THE SKELETAL PATTERN OF DECIDUOUS ANTERIOR CROSSBITE

Some patients who have an anterior crossbite in the deciduous dentitio n lose the crossbite during the transitional stage to permanent anteri or teeth without orthodontic and/or orthopedic treatment. We observed 220 anterior crossbite patients at regular intervals and identified th ree groups of patients: in group N (n=16) the crossbite corrected when the central incisors erupted; in group R-1 (n=16) the crossbite was w ithin 52,51\61,82/83,82,81\71,72,73 and remained unchanged following t he eruption of the permanent central incisors; in group R-2 (n=12) the crossbite extended over 52,51\61,62/83,82,81\71,72,73 and remained fo llowing the eruption of the permanent central incisors. The purpose of this study was to determine whether any differences existed among the above three groups at the initial examination, or if differences aros e during eruption of the teeth. The findings indicate that the mandibu lar position in group N was more posterior than in groups R-1 and R-2, and the lengths of Pog'-Go and Gn-Cd in group N were smaller. Tooth a xis of the lower incisors in groups R-1 and R-2 showed lingual tipping , and the maxilla in group R-2 was underdeveloped. The findings of the longitudinal changes indicated that the maxillary length in group N i ncreased and mandibular forward growth was suppressed. The initial max illary position in groups R-1 and R-2 remained much the same until the permanent central incisors erupted.