There is relatively little appreciation of the changes in maxillary-mandibular relationships occurring during adolescence among subjects with normal and increased overjet. The aim of this study was to assess differences in changes in maxillo-mandibular relationships during the adolescent growth period based on the presence of a normal (< 4 mm) or increased (> 4 mm) overjet in childhood. Our hypothesis was that there is no difference in the change of the A point, nasion, B point (ANB) angle during growth between these two overjet groups. Lateral cephalograms were obtained from 65 subjects taken from the American Association of Orthodontists Foundation (AAOF) Craniofacial Growth Legacy Collections Project. Cephalograms were obtained at ages 7–10 (T0) and 14–17 (T1) with allocation into two groups based on baseline overjet (> 4 mm: group 1, 2-4 mm: group 2). Random effects linear regression was used to account for multiple within -patient measurements with dependent variables including antero-posterior skeletal pattern (based on sella, nasion, A point (SNA); sella, nasion, B point (SNB); and ANB angles). We included a similar number of males (n = 34; 52.3%) and females (n = 31; 47.7%). The mean ANB was higher at baseline in group 1 (5.42, SD 2.16°) than in group 2 (3.08, SD 1.91°). The hypothesis was rejected as the ANB angle reduced by 1.92° more in the larger overjet group with the association being statistically significant after accounting for age and gender (P < 0.001; 95% CI 1.06 to 2.77). No significant gender-related effect (P = 0.624; 95% CI − 0.637 to 1.07) was observed overall. However, there was no significant increase in SNA angle in the > 4 mm overjet group compared to the 2–4 mm group (0.857°, P = 0.271; 95% CI − 0.669 to 2.383). The SNB angle increased by 1.15° more in the higher overjet group but there was only weak evidence of an association (P = 0.086; 95% CI − 2.464 to 0.164). A slight straightening of the facial profile was observed in both groups with a statistically significant greater reduction in ANB arising in the group with larger baseline overjet. This translated into a marginal reduction in the overjet in this group.

中文翻译：

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从儿童期到青春期的II类错牙合的骨骼生长：轮廓是否变直？

对于正常和过度喷射的受试者，青春期期间发生的上颌-下颌关系的变化的了解相对较少。这项研究的目的是根据儿童时期正常（<4毫米）或增加（> 4毫米）的过喷射来评估青春期下颌骨关系变化的差异。我们的假设是，这两个过喷射组之间在生长过程中A点，鼻根，B点（ANB）角度的变化没有差异。侧位脑电图是从65位受试者中获得的，这些受试者来自美国正畸医师协会基金会（AAOF）颅面生长遗产收集项目。头颅图是在7-10岁（T0）和14-17岁（T1）获得的，并根据基线过喷射量（> 4 mm：分为第1组，分为两组）2-4毫米：第2组）。随机效应线性回归用于解释患者内的多个测量结果，并具有因变量，包括前后骨骼模式（基于蝶鞍，鼻孔，A点（SNA）；蝶鞍，鼻孔，B点（SNB）和ANB角度） 。我们纳入了类似数量的男性（n = 34； 52.3％）和女性（n = 31； 47.7％）。第一组的平均ANB在基线（5.42，SD 2.16°）高于第二组（3.08，SD 1.91°）。该假设被拒绝了，因为在较大的过喷射组中，ANB角减小了1.92°，在考虑了年龄和性别之后，该关联具有统计学意义（P <0.001； 95％CI 1.06至2.77）。总体上未观察到明显的性别相关影响（P = 0.624； 95％CI-0.637至1.07）。但是，> 4 mm过喷射组与2-4 mm组相比（0.857°，P = 0.271； 95％CI-0.669至2.383）。在较高的过喷射组中，SNB角增加了1.15°，但仅有弱关联的证据（P = 0.086； 95％CI-2.464至0.164）。在两组中均观察到面部轮廓略微拉直，基线过喷射量较大的组中ANB的减少具有统计学意义。这意味着该组的过喷射量略有减少。在两组中均观察到面部轮廓略微拉直，基线过喷射量较大的组中ANB的减少具有统计学意义。这意味着该组的过喷射量略有减少。在两组中均观察到面部轮廓略微拉直，基线过喷射量较大的组中ANB的减少具有统计学意义。这意味着该组的过喷射量略有减少。