基于CBCT的下颌第一磨牙区即刻种植相关的影像学研究

Imaging study on immediate implantation of mandibular first molar based on CBCT

目的利用CBCT研究下颌第一磨牙区即刻种植适宜的植入位点、植入角度与植入深度,为术前数字化设计和临床操作提供参考依据。方法选取100例符合纳入标准的患者CBCT影像学资料,测量下颌第一磨牙区的牙槽骨厚度、颊侧及舌侧骨板厚度、牙根间隔宽度,同时测量下颌第一磨牙与下颌神经管及舌侧骨倒凹的关系,并进行统计学分析。结果由近中至远中,下颌第一磨牙的牙槽骨厚度及颊侧骨板厚度逐渐增大,舌侧骨板厚度逐渐减小;由牙槽嵴顶至根尖,牙根间隔宽度逐渐增大,最大为(5.00±1.42)mm;近中根、远中根、远舌根、牙根间隔顶至下颌神经管的距离分别为(7.47±2.38)mm、(7.19±2.49)mm、(9.59±1.94)mm、(15.90±2.39)mm;由近中至远中,下颌神经管颊侧及舌侧骨板最大厚度分别为(6.54±1.25)mm、(2.53±0.84)mm;下颌舌侧骨倒凹角度为(149.67±8.30)°,倒凹深度为(1.51±0.43)mm。结论在下颌第一磨牙区即刻种植前可通过CBCT规划合适的种植路径,注意避开下颌神经管和舌侧骨倒凹。若根尖至下颌神经管的安全距离足够,可从牙根间隔处植入,若安全距离不足,植入位点可偏近中舌侧,植入角度可适当舌倾。

Objective To investigate the appropriate inserting position,direction and depth of immediate implantation for mandibular first molar by using cone-beam computed tomography(CBCT),and to provide a basis for preoperative digital design and clinical operation.Methods One hundred CBCT images of patients who met the inclusion criteria were selected.The thicknesses of alveolar bone,buccal and lingual bone plate and the width of interradicular septum in mandibular first molar position were measured.Simultaneously,the relationship between mandibular first molar and mandibular nerve canal and lingual bone concavity was measured.Then the statistical analysis was performed.Results From the mesial to the distal side,the thicknesses of the alveolar bone and the buccal bone plate gradually increased,while the thickness of the lingual bone plate gradually decreased.From the coronal to apical direction,the width of the interradicular septum gradually increased,with a maximum width of(5.00±1.42)mm.The distances from the mandibular nerve canal to the mesial apex,the distal apex,the distal-lingual apex and the interradicular septum were respectively(7.47±2.38)mm,(7.19±2.49)mm,(9.59±1.94)mm and(15.90±2.39)mm.From the mesial to the distal side,the maximum distances from the mandibular nerve canal to the buccal and lingual cortical bone surfaces were(6.54±1.25)mm and(2.53±0.84)mm.The angle of the mandibular lingual bone concavity was(149.67±8.30)°,and the depth of the concavity was(1.51±0.43)mm.Conclusion Before performing the immediate implantation in the mandibular first molar region,it is necessary to design the inserting path using CBCT images,keeping a safe distance from the mandibular nerve canal and the lingual bone concavity.If the safe distance between the apex and the mandibular nerve canal is adequate,the interradicular septum will be a suitable position for implanting.Otherwise,the implant can be placed in a mesial-lingual side and inclined slightly lingually.