The purpose of this study was to investigate the effect of a Hotz plate on development of the maxillary alveolar arch. Gypsum models were obtained from 12 patients with unilateral cleft lip and palate (UCLP) who were treated with a Hotz plate at the time of presentation, lip repair, and palate repair. The models were then measured three-dimensionally with a device called “SURFLASER VMS-250R” (UNISUN Co.). Ten patients who did not wear a Hotz plate were studied as control. In this group, gypsum models were taken at the time of palate repair.
Results:
1. Before setting the Hotz plate, the incisive point was situated on the normal side away from the midplane. Cleft width was 9.4 ± 3.4mm at the alveolar region, 10.3 ± 3.0mm at the anterior palatal region and 12.6 ± 1.5mm at the posterior palatal region.
2. After setting the Hotz plate, the incisive point moved in the anterior, inferior, and medial directions close to the midplane. The tip of the cleft edge on the major segment moved in the anterior, inferior, and lateral directions, and the cleft edge on the minor segment shifted anteriorly and medially. The anterior cleft margin of the major segment moved in the inferior and medial directions, and the minor segment moved medially. The posterior region of the cleft margin bilaterally moved to a more superior and medial position. Thus, the cleft narrowed to 2.9 ± 2.9mm at the alveolar region, 1.8 ± 1.9mm at the anterior palatal region and 8.8 ± 2.3mm at the posterior palatal region. The rate of increase in the superficial content of the minor segment was greater than that of the major segment.
3. The incisive point and canine points were situated more anteriorly in patients with a Hotz plate than in patients in the control group. Furthermore, the superficial content of the palatal surface in patients with a Hotz plate was significantly larger than that in the control group.
4. Our results suggest that the Hotz plate is effective not only for adjusting the alveolar arch form but also for increasing palato-alveolar growth.
