【作者】 倪琳；

【导师】 丁寅；

【作者基本信息】 第四军医大学 ， 口腔临床医学， 2002， 硕士

【摘要】 后牙反(牙合)是一种临床常见的错(牙合)畸形，其中多数患者为单侧后牙反(牙合)。单侧后牙反(牙合)患者在下颌的闭口运动过程中，常由于(牙合)干扰的存在及没有适当的牙尖引导，使下颌发生侧向移动，可能引起颞颌关节、颌骨肌肉等方面的功能紊乱，从而影响口颌、牙(牙合)系统的健康。 乳牙列或混合牙列的单侧后牙反(牙合)，随着生长发育，往往不能自行纠正。如未在儿童期进行治疗，将引起颞颌关节的病理性重建、面部的不对称及下颌牙列中线的偏斜。但是否可引起颌骨两侧形态的不对称，目前还不明确。 本研究以儿童及成人单侧后牙反(牙合)患者为实验组，以正常(牙合)者为对照组。通过对头颅定位颏顶位X线片及校正的颞颌关节中位断层X线片进行测量分析，研究错(牙合)畸形与骨性不对称之间是否存在必然联系。 研究分三部分： 1．儿童单侧后牙反(牙合)患者下颌及颞颌关节的对称性研究 以26例儿童单侧后牙反(牙合)患者为实验组，28例正常(牙合)儿童为对照组。拍摄头颅定位颏顶位X线片及校正的颞颌关节中位断层X线片。结果显示：相对于颅底坐标系，单侧后牙反(牙合)患者在前后向及横向都存在显着的不对称。这或许是下颌的功能性侧方移动造成的。但相对于下颌骨坐标系，未见骨性结构的不对称。单侧后牙反(牙合)的儿童，在牙尖交错位时，双侧髁突位置及关节间隙存在不对称。 2．成人单侧后牙反(牙合)患者下颌及颞颌关节的对称性研究 第四早医大学可士学位论文 以ZI例成人单侧后牙反抬患者为实验组，23例正常党成人为照组。拍 摄头颅定位颊顶位X线片及校正的额颌关节中位断层X线片。结果显示： 相对十颅底坐标系，单侧后牙反胎患者在前后向及横向都存在显着的不对 称。认为是单侧后牙反抬患者的下颌相对颅底平面发生了旋转。单侧后牙反 邪与牙列的对称性相关，但并末发现骨性结构的不对称。 3．单侧后牙反抬对下颌及额颌关节生长发育的影响。 以ZI例成人单侧后牙反抬患者为实验组，以26例儿童单侧后牙反抬患 者为对照组。拍摄头颅定位颈顶位X线片及校正的颤颌关节中位断层X线 片。结果显示：相对于颅底坐标系及下颌骨坐标系，二者在骨性结构上均未 见有明显差异。非反抬侧的骸突应置及关节间隙在两组间存在显着差异。回 而不认为单侧后牙反胎将造成下颌的骨性结构不对称。在几童期为适应不对 称殆关系而出现的躲突位置不对称通过生长改建而逐渐趋向双侧平衡。更多还原

【Abstract】 Posterior crossbites is one of the most frequently occurring malocclusion. Most of them are unilateral posterior crossbites. In patients with functional unilateral posterior crossbites, the mandibular shifts laterally toward the crossbites side on closure from opening to maximum intercuspation, often as a result of poor interdigitation and occlusion interference. That may develop into musculoskeletal problems, leading to a functional disturbance.Posterior crossbites, if left untreated, will usually persist from childhood into adulthood, the proposition has been made that untreated crossbite lead to growth alterations resulting in asymmetry on dentition, skeletal remodeling of the temporo-mandibular joints and facial asymmetry. But whether there is a definitive relationship between malocclusion and mandibular asymmetry is still unknown.In this study, patients with unilateral posterior crossbite were as sample andcompare with patients exhibiting nomalocclusion. The present study used SMV radiographs to evaluate asymmetry in the mandibular dentoalveolar or skeletal regions that might be associate with unilateral posterior crossbite. The study consists of three parts:1. Mandibular asymmetry and condylar position in children with unilateral posterior crossbite.The sample consists of 26 children with unilateral posterior crossbite. 28 children with nomalocclusion were as the control. The result showed that: Relative to the cranial floor coordinate system, the mandible in the unilateral posterior crossbite group exhibited significant asymmetry both in the anteroposterior as well as transverse dimension. The asymmetries were probably the result of a functional deviation of the mandible. With referencee to the mandibular coordinate system, no skeletal asymmetry of the mandible was found in the crossbite group. Children with UPCB have asymmetry condylar position in centric occlusion.2. Mandibular asymmetry and condylar position in adults with unilateral posterior crossbite.The sample consists of 21 adults with unilateral posterior crossbite. 23 adults with nomalocclusion were as the control. The result showed that: Relative to the cranial floor coordinate system, the mandible in the unilateral posterior crossbite group exhibited significant asymmetry both in the anteroposterior as well as transverse dimension. The present study found that the mandible in adults with unilateral posterior crossbite was "rotated" when related to the cranial floor, and its dentoalveolar segment was asymmetry. There was no demonstrable mandibular skeletal asymmetry in the unilateral posterior crossbite group.3. The effects of unilateral posterior crossbite to growth and development of mandibular and condylar.-6-The sample consists of 26 children with unilateral posterior crossbite. 21 adults with unilateral posterior crossbite were as the control. The result showed that: Relative to both the cranial floor coordinate system and the mandibular coordinate system, none of the skeletal variables were found to be sianificant between the groups. So the belief that untreated unilateral posterior crossbite lead to skeletal asymmetry of the mandibular was not supported by this study. The remodeling changes took place in condylar head in response to unilateral posterior crossbite.更多还原