Department of Oral and Maxillofacial Surgery, Barts and the London School of Medicine and Dentistry, London, UK.
Community Dental Service, Barts and the London School of Medicine and Dentistry, London, UK.
Prog Orthod. 2020 May 18;21(1):13. doi: 10.1186/s40510-020-00313-9.
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.
对于正常覆 和深覆 的儿童，人们对其在青春期上颌-下颌关系变化的认识相对较少。本研究旨在评估基于儿童时期正常（<4mm）或深覆 （>4mm）的前提下，在青春期生长过程中上颌-下颌关系变化的差异。我们的假设是，在生长过程中，这两个覆 组的 A 点、鼻根点（Nasion）、B 点（ANB）角度的变化没有差异。从美国正畸医师协会基金会（AAOF）颅面生长遗产收藏项目中获取了 65 名受试者的侧位头颅侧位片。头颅侧位片在 7-10 岁（T0）和 14-17 岁（T1）时拍摄，并根据基线覆 分为两组（>4mm：组 1，2-4mm：组 2）。使用随机效应线性回归来解释多个患者内测量，因变量包括前后骨骼模式（基于蝶鞍、鼻根点、A 点（SNA）；蝶鞍、鼻根点、B 点（SNB）和 ANB 角）。
我们纳入了相似数量的男性（n=34；52.3%）和女性（n=31；47.7%）。组 1 的基线 ANB 更高（5.42，SD 2.16°），组 2 为 3.08，SD 1.91°。由于年龄和性别因素的影响，假设被拒绝，较大覆 组的 ANB 角减少了 1.92°，且关联具有统计学意义（P<0.001；95%CI 1.06 至 2.77）。总体而言，没有观察到与性别相关的显著影响（P=0.624；95%CI-0.637 至 1.07）。与 2-4mm 组相比，>4mm 覆 组的 SNA 角没有明显增加（0.857°，P=0.271；95%CI-0.669 至 2.383）。较高覆 组的 SNB 角增加了 1.15°，但关联证据较弱（P=0.086；95%CI-2.464 至 0.164）。
两组均观察到面部轮廓略有变直，较大基线覆 的组中 ANB 的减少具有统计学意义。这导致该组的覆 略有减少。
