Doris J M, Bernard B W, Kuftinec M M, Stom D
Am J Orthod. 1981 Mar;79(3):326-36. doi: 10.1016/0002-9416(81)90080-4.
A study was conducted for the purpose of comparing mesiodistal tooth widths between a group of patients with good tooth alignment and a group of patients with crowded dental arches. Crowded arches were defined as those with more than 4 mm. of space deficiency. The hypothesis tested was whether the arches with more than 4 mm. of crowding consistently had larger teeth than the ones with lesser or no crowding. The difference in sizes between the groups (forty males and forty females) for all teeth measured was found to be statistically significant (p less than 0.001). The multivariate data analysis indicated that the two groups were derived from two different populations and that the maxillary lateral incisors and second premolars and the mandibular canines and premolars were particularly different in these groups. It was also determined that the teeth in males were uniformly larger than in females, but not to a statistically significant level. There was less correlation, however, between the sex and the status of the tooth alignment in dental arches, so that both sexes had similar distribution of crowding versus noncrowding. On the basis of this study of eighty North American Caucasians, it is suggested that one should consider the sum of mesiodistal widths of teeth, in addition to the arch length analysis, in formulating an orthodontic treatment plan. When the cumulative tooth mass of the twenty permanent teeth is 140 mm. or more, the clinician may want to consider extraction therapy for such a case.
为比较一组牙齿排列良好的患者与一组牙弓拥挤患者的近远中牙宽度，进行了一项研究。牙弓拥挤被定义为存在超过4毫米的间隙不足。所检验的假设是，拥挤超过4毫米的牙弓的牙齿尺寸是否始终大于拥挤程度较小或无拥挤的牙弓。在测量的所有牙齿中，两组（40名男性和40名女性）之间的尺寸差异具有统计学意义（p小于0.001）。多变量数据分析表明，这两组来自两个不同的总体，上颌侧切牙、第二前磨牙以及下颌尖牙和前磨牙在这两组中差异尤为明显。还确定男性的牙齿总体上比女性大，但未达到统计学显著水平。然而，性别与牙弓中牙齿排列状况之间的相关性较小，因此男性和女性在拥挤与不拥挤方面的分布相似。基于对80名北美白种人的这项研究，建议在制定正畸治疗计划时，除了牙弓长度分析外，还应考虑牙齿近远中宽度的总和。当20颗恒牙的累计牙量为140毫米或更多时，临床医生可能需要考虑对此类病例进行拔牙治疗。
