Li Yuhan, Li Kexin, Li Xiangyi, Yin Yibiao, Ren Zilong, Cai Sijia, Yan Xiulin
Department of Orthodontics, School and Hospital of Stomatology, Shenyang clinical medical research center of orthodontic disease, China Medical University, NO.117, Nanjing North Street, Heping District, Shenyang, 110002, Liaoning, China.
Department of Stomatology, Chongqing Hospital, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Chongqing, China.
Clin Oral Investig. 2025 Sep 16;29(10):455. doi: 10.1007/s00784-025-06540-w.
To evaluate the effects of different pretreatment sinus-root relationships on external apical root resorption (EARR) and apical root displacement (ARD) of maxillary molars in maxillary premolar extraction treatment using a split-mouth design.
Paired palatal roots of maxillary molars with different sinus-root relationships from the same patients were included in groups based on pretreatment CBCT. The relationships were classified as follows: type I, root separated from the maxillary sinus floor (MSF); type II, root contacting MSF; and type III, root protruding into the maxillary sinus. Pretreatment and posttreatment CBCT images were superimposed to quantify three-dimensional ARD. EARR length was measured post-orthodontics. Groups I vs. II and II vs. III were analyzed using paired t-tests/Wilcoxon tests, respectively. Analysis of associated factors was conducted using Generalized Estimating Equations (GEE).
Mean EARR was < 1 mm across all types. Type II roots exhibited greater extrusive displacement in vertical ARD (P < 0.01) and increased EARR (P < 0.001) compared to type I. Type III roots demonstrated reduced mesial ARD compared to type II (P < 0.05), with no significant difference in EARR between types II and III. Type II roots were found to promote more EARR than type I (P < 0.001), while type III roots restricted mesial ARD compared to type II (P < 0.05).
Roots contacting MSF before orthodontic treatment increase EARR of maxillary molars, though the values remain clinically acceptable. Protrusion into the maxillary sinus prior to orthodontic treatment restricts the mesial movement of molar roots in the maxillary premolar extraction treatment, suggesting MSF morphology modulates orthodontic outcomes, duration, and anchorage demands.
A pretreatment evaluation of sinus-root relationship is recommended to anticipate the sequelae and biomechanical limitation in maxillary molars. However, complications from MSF proximity rarely necessitate excessive concern from orthodontists clinically.
采用自身对照设计，评估在上颌前磨牙拔除治疗中，不同的治疗前窦根关系对上颌磨牙根尖外吸收（EARR）和根尖根位移（ARD）的影响。
根据治疗前CBCT，将同一患者具有不同窦根关系的上颌磨牙腭侧根对分组。关系分类如下：I型，牙根与上颌窦底（MSF）分离；II型，牙根接触MSF；III型，牙根突入上颌窦。将治疗前和治疗后的CBCT图像叠加，以量化三维ARD。正畸治疗后测量EARR长度。分别使用配对t检验/威尔科克森检验对I组与II组、II组与III组进行分析。使用广义估计方程（GEE）进行相关因素分析。
所有类型的平均EARR均<1mm。与I型相比，II型牙根在垂直ARD中表现出更大的挤出位移（P<0.01），EARR增加（P<0.001）。与II型相比，III型牙根的近中ARD减少（P<0.05），II型和III型之间的EARR无显著差异。发现II型牙根比I型牙根促进更多的EARR（P<0.001），而与II型相比，III型牙根限制近中ARD（P<0.05）。
正畸治疗前接触MSF的牙根会增加上颌磨牙的EARR，尽管该值在临床上仍可接受。正畸治疗前突入上颌窦会限制上颌前磨牙拔除治疗中磨牙牙根的近中移动，提示MSF形态会调节正畸结果、持续时间和支抗需求。
建议对窦根关系进行治疗前评估，以预测上颌磨牙的后遗症和生物力学限制。然而，临床上正畸医生很少需要过度担心因接近MSF而产生的并发症。
