Defraia Efisio, Baroni Giulia, Marinelli Andrea
Department of Orthodontics, University of Florence, Via del Ponte di Mezzo 46-48, 50127 Florence, Italy.
Angle Orthod. 2006 May;76(3):446-51. doi: 10.1043/0003-3219(2006)076[0446:DADITM]2.0.CO;2.
The objective of this study was to compare the dental arch dimensions in the mixed dentition in two modern samples living in the same geographic area and separated by almost 35 years. A group of 83 subjects (39 boys and 44 girls) born between 1953 and 1959 (mean age: eight years and three months +/-15 months for the boys and seven years and 11 months +/-12 months for the girls) were compared with a group of 84 subjects (38 boys and 46 girls) born between 1990 and 1998 (mean age: eight years and eight months +/-12 months for the boys and eight years and four months +/-11 months for the girls). Measurements were taken on dental casts for posterior and anterior arch segments, intermolar and intercanine width, and mesiodistal size of incisors. The available anterior space in both arches and the posterior and anterior transverse dimensions were calculated. Groups were compared using a nonparametric test (Mann-Whitney U-test) for independent samples (P < .05). Results show that both boys and girls of 1990s showed significantly smaller maxillary intermolar width when compared with 1950s. Posterior transverse interarch discrepancy was significantly minor in girls of 1990s. The present population has a greater probability of developing a malocclusion as a consequence of the secular trend toward the reduction of the width of the upper arch.
本研究的目的是比较生活在同一地理区域、相隔近35年的两个现代样本在混合牙列期的牙弓尺寸。将一组83名受试者（39名男孩和44名女孩）与另一组84名受试者进行比较，第一组受试者出生于1953年至1959年之间（男孩平均年龄：8岁3个月±15个月，女孩平均年龄：7岁11个月±12个月），第二组受试者出生于1990年至1998年之间（男孩平均年龄：8岁8个月±12个月，女孩平均年龄：8岁4个月±11个月）。对牙模进行测量，以获取牙弓后段和前段、磨牙间宽度、尖牙间宽度以及切牙的近远中尺寸。计算两个牙弓中可用的前部间隙以及前后横向尺寸。使用非参数检验（曼-惠特尼U检验）对独立样本进行组间比较（P < 0.05）。结果显示，与20世纪50年代相比，20世纪90年代的男孩和女孩上颌磨牙间宽度均显著更小。20世纪90年代女孩的后牙弓横向差异明显更小。由于上牙弓宽度呈长期减小趋势，当前人群发生错牙合畸形的可能性更大。
