Yavuz Ibrahim, Baydaş Bülent, Ikbal Ayşegül, Dağsuyu Ilhan Metin, Ceylan Ismail
Department of Orthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey.
Am J Orthod Dentofacial Orthop. 2006 Nov;130(5):634-8. doi: 10.1016/j.ajodo.2005.02.026.
The aim of this study was to evaluate whether early loss of the permanent first molars has an effect on the developmental stages and eruptive conditions of the third molars.
Panoramic radiographs and dental casts of 165 adolescent patients (103 boys, 62 girls) with unilateral early loss of a permanent first molar were used to assess the developmental stages of the third molars. The formation stages of third molars on the extraction sides were evaluated, and the formative conditions of the contralateral teeth were used as controls. The Mann-Whitney U test was used to assess sex differences in formation stages of the third molars. The Kruskal-Wallis analysis of variance (ANOVA) was used to determine whether there were significant differences in the developmental stages of the third molars between the various extraction quadrants. In addition, the Wilcoxon signed rank test and the paired t test were used to compare the differences in the developmental stages and eruptive conditions of the third molars between the extraction and control sides.
The Mann-Whitney U test showed no significant sex differences for the formation stage of the third molars. Therefore, the data from both sexes were pooled. No statistically significant differences were found in the developmental stages of the third molars between the various extraction quadrants in the same jaw and between those in the mandible and maxilla. However, statistically significant differences were found in developmental stages (P <.001) and eruptive conditions (P <.05) of the third molars between the extraction and control sides. The development of the third molars on the extraction side was significantly accelerated compared with the contralateral teeth.
Early loss of the permanent first molars might have an accelerating effect on the development of the third molar on the extraction side compared with the contralateral teeth. Therefore, emergence of the third molars on the extraction side might be hastened, and these teeth might erupt earlier than the contralateral teeth.
本研究的目的是评估恒牙第一磨牙的早期缺失是否会对第三磨牙的发育阶段和萌出情况产生影响。
对165例单侧恒牙第一磨牙早期缺失的青少年患者（103例男孩，62例女孩）的全景X线片和牙模进行分析，以评估第三磨牙的发育阶段。对拔牙侧第三磨牙的形成阶段进行评估，并将对侧牙齿的形成情况作为对照。采用曼-惠特尼U检验评估第三磨牙形成阶段的性别差异。采用Kruskal-Wallis方差分析（ANOVA）确定不同拔牙象限的第三磨牙发育阶段是否存在显著差异。此外，采用Wilcoxon符号秩检验和配对t检验比较拔牙侧和对照侧第三磨牙的发育阶段和萌出情况的差异。
曼-惠特尼U检验显示第三磨牙形成阶段不存在显著的性别差异。因此，将两性的数据合并。在同一颌骨的不同拔牙象限之间以及下颌骨和上颌骨之间的第三磨牙发育阶段未发现统计学上的显著差异。然而，在拔牙侧和对照侧的第三磨牙发育阶段（P <.001）和萌出情况（P <.05）方面发现了统计学上的显著差异。与对侧牙齿相比，拔牙侧第三磨牙的发育明显加速。
与对侧牙齿相比，恒牙第一磨牙的早期缺失可能会对拔牙侧第三磨牙的发育产生加速作用。因此，拔牙侧第三磨牙的萌出可能会提前，并且这些牙齿可能比对侧牙齿更早萌出。
