不同垂直骨面型成人微螺钉种植体常植入区骨皮质厚度分析

目的 探讨不同垂直骨面型成人上下颌骨后牙区微螺钉种植体拟植入部位的骨皮质厚度,为临床植入微螺钉种植体提供参考.方法 57例正畸成人患者,髙角组20例、均角组22例、低角组15例;拍摄头颅CBCT,在三维重建模型上测量上颌骨颊、腭侧及下颌骨颊侧骨皮质厚度,进行统计学分析.结果 3组间多数测量部位平均骨皮质厚度的差异均有统计学意义(P<0.05),且高角组的平均骨皮质厚度最小,低角组的平均骨皮质厚度最大.结论 髙角患者在上颌后牙区植入微螺钉种植体需谨慎.     

不同垂直骨面型成人下颌骨皮质厚度的锥形束CT研究

目的:通过测量分析不同垂直骨面型的成人下颌后牙区颊侧骨皮质厚度,为正畸临床治疗中不同骨面型患者种植支抗类型的选用和植入部位的确定提供参考。方法:在成年正畸患者中,按照下颌平面角测量值及纳入标准选择45例病例,均分为高角、均角和低角3组。利用CBCT采集患者颅面部数据并进行三维重建,对下颌后牙区颊侧不同高度（距牙槽嵴顶4、6、8mm处）的骨皮质厚度进行测量,应用SPSS11.0软件包对数据进行方差分析和LSD检验。结果:3组在下颌后牙区骨皮质厚度为高角组<均角组<低角组,同组内厚度4 mm组<6 mm组<8 mm组,有显著差异（P<0.05）。结论:下颌颊侧4 mm处即可进行种植支抗植入,而低角组的骨皮质厚度较高,最好选用助攻法。     

成人不同垂直骨面型颧牙槽嵴区骨皮质密度分析

目的 通过三维重建技术对成人颧牙槽嵴区骨皮质密度进行测量分析,比较不同骨面型间颧牙槽嵴区骨皮质密度以及不同位点间骨皮质密度的差异。方法 选取成人患者螺旋 CT 图像60例（男28例,女32例）进行三维重建,根据下颌平面角( FH-MP) 的大小分为低角、均角、高角3组,分别测量上颌左侧颧牙槽嵴区不同层面基准线上方13、15、17 mm处的骨皮质密度,采用 SPSS 17.0软件包进行数据分析。结果 颧牙槽嵴区骨密度在性别之间无统计学差异;在不同垂直骨面型间存在统计学差异（P<0.05),其中,低角组[(1331.65±185.70) HU]的骨密度最高,高角组[(1245.62±207.63) HU]最低;在不同垂直骨面型组的不同位点之间骨密度存在统计学差异（P<0.05),各组骨密度的集中区域是,高角组位于第一磨牙近中颊根层面,均角组位于近、远中颊根之间,低角组位于第一磨牙远中颊根层面。结论 成人不同垂直骨面型间颧牙槽嵴区骨皮质的密度以及位点分布存在显著差异,该研究为成人选择微种植支抗钉的适宜部位,保证正畸治疗中支抗钉的稳定性提供了参考依据。     

青少年上颌后牙区微种植钉的植入角度研究

目的 通过对不同垂直骨面型患者上颌后牙区的锥形束计算机体层摄影片（CBCT）分析,探讨上颌颊腭向骨质在不同种植植入角度下的厚度,为临床微种植钉植入提供参考.方法 选取60 例Ⅱ类矢状骨面型青少年患者,依照垂直骨面型分为低角、均角和高角三组,进行CBCT 扫描和三维重建.分别测量上颌第二前磨牙与第一磨牙根间区牙槽嵴顶到上颌窦底的高度,并分别测量距离牙槽嵴顶4 mm 处,与相邻牙长轴成90°、60°、45°和30°四个颊侧植入角度的骨质厚度.结果 （1）不同垂直骨面型间,上颌窦底高度的差异有统计学意义（F＝23.66,P ＜ 0.05,低角型最大,高角型最小）;（2）不同垂直骨面型组在相同的植入角度下,骨质厚度的差异有统计学意义,两两比较低角型与高角型间的差异有统计学意义,低角型组大于高角型组（P ＜ 0.05）;（3）同一垂直骨面型组在不同植入角度下,骨质厚度的差异有统计学意义,两两比较45°、30°植入角和90°、60°植入角度间,差异具有统计学意义,90°组、60°组大于45°组、30°组（P ＜ 0.05）.结论 相同植入条件下,Ⅱ类矢状骨面型高角型青少年患者较低角型穿通上颌窦的风险更大.     

不同垂直骨面型正常（牙合）人切牙区颌骨形态结构特点

目的研究不同垂直骨面型正常（牙合）人切牙区颌骨的形态结构特征。方法通过X线头影测量技术对169名恒牙初期正常（牙合）人进行研究。结果①高角面型齿槽骨厚度窄、切牙区颌骨高度大。低角面型具有相反的形态特征。②在不同垂直骨面型中，上下颌切牙区颌骨形态结构在前后向的代偿变化，主要是腭（舌）侧骨皮质板发生代偿倾斜变化③相对于前颅底平面，正常绐人高角面型上颌切牙、切牙区颌骨代偿性竖直；低角面型代偿前倾。相对于下颌平面，高角面型下颌切牙、切牙区颌骨代偿竖直；低角面型代偿前倾。结论正常（牙合）人切牙区颌骨的形态结构与垂直骨面型联系密切。     

安氏Ⅱ类1分类患者后牙区颊侧皮质骨厚度分析

目的探讨不同年龄和性别的安氏Ⅱ类1分类患者后牙区颊侧皮质骨厚度的差异,为临床精准植入微种植钉提供理论依据。方法选取安氏Ⅱ类1分类患者多层螺旋CT三维重建影像资料88例,分为青少年男性组、青少年女性组、成年男性组和成年女性组4组,各组病例数为22例,测量上颌第二双尖牙和第一恒磨牙间及下颌第一、第二磨牙间,距离牙槽嵴顶3、5、7mm水平的颊侧皮质骨厚度,并对测量结果进行统计学分析。结果上颌第二双尖牙和第一恒磨牙间距离牙槽嵴顶3、5、7mm水平的颊侧皮质骨厚度分别为（1．21±0．21）mm、（1．29±0．20）mm和（1．42±0．19）nun;下颌第一、第二磨牙间距离牙槽嵴顶3、5、7mm水平的颊侧皮质骨厚度分别为（2．23±0．30）mm、（2．70±0．30）mm和（3．09±0．27）mm。青少年组与成年组之间在各水平的颊侧皮质骨厚度差异无统计学意义（P〉0．05）;男性与女性之间在各水平的颊侧皮质骨厚度差异无统计学意义（P〉0．05）。结论上颌第二双尖牙和第一恒磨牙及下颌第一、第二磨牙间皮质骨厚度在青少年与成人之间或男女之间无明显差异;以上部位距离牙槽嵴顶3、5、7mm水平的颊侧皮质骨厚度均可满足微种植钉植入要求。     

下颌后牙区颊侧骨皮质厚度及牙槽宽度的CBCT测量分析

目的应用CBCT测量成人下颌后牙区颊侧骨皮质厚度及牙槽宽度,为临床选择适宜微种植体种类及植入部位提供参考。方法从中国医科大学口腔医院影像科资料库中随机选取68例成人患者的CBCT。男36例,女32例;年龄18³1岁,平均22.8岁。分别测量下颌第一前磨牙至第二磨牙近中两牙根间距牙槽嵴顶3、6、9 mm处骨皮质厚度及牙槽宽度,并对测量结果进行统计分析。结果下颌后牙区颊侧骨皮质厚度及牙槽宽度,左右两侧无统计学差异,性别间无统计学差异(P>0.05)。在3个测量水平第一磨牙与第二磨牙根间颊侧骨皮质及牙槽宽度均最厚,第一前磨牙与第二前磨牙根间区最薄,差异有统计学意义(P<0.05)。结论应用CBCT三维重建能够对拟植入微种植体部位进行测量分析,充分了解植入部位骨质骨量情况及相关解剖条件。下颌后牙区不同部位颊侧骨皮质厚度及牙槽宽度存在差异,有自方向根方,自近中向远中增加的趋势,微种植体植入过程中应考虑这一因素。     

不同生长型正常牙合成人上颌第一磨牙牙槽骨厚度CBCT分析

目的    基于锥形束计算机断层扫描（CBCT）数据,比较不同垂直骨面型正常牙合成人上颌第一磨牙颊腭侧不同高度平面牙槽骨厚度的差异。 方法    2013年5月至2014年8月选取解放军第306医院口腔科普查得到的19 ~ 40岁中国汉族正常牙合成人82名,其中高角组32名,低角组50名。测量其CBCT片上的上颌第一磨牙近颊根颊侧、远颊根颊侧及腭根腭侧牙槽骨厚度的相应指标,利用SPSS17.0统计软件对测量结果进行比较分析。 结果    正常牙合成人上颌第一磨牙近颊根颊侧牙槽骨厚度在根尖1/4区低角组大于高角组（P < 0.05）;低角组近颊根颊侧牙槽骨厚度在3/4、1/2和1/4牙根水平均远远小于远颊根颊侧牙槽骨厚度（均P < 0.05）;高角组近颊根颊侧牙槽骨厚度在3/4、1/2牙根水平远远小于远颊根颊侧牙槽骨厚度（P < 0.05）。结论    正常牙合成人上颌第一磨牙颊侧牙槽骨厚度与垂直骨面型有关,临床上应考虑这一因素。     

锥形束CT对微螺钉植入后牙安全区域的分析

目的通过锥形束CT（CBCT）测量上下颌后牙区不同高度牙槽骨近远中向及颊舌（腭）向的骨量,分析微螺钉种植体植入的安全区域。方法选取30例CBCT扫描的成人影像资料为研究对象,对颌骨进行扫描重建,从第前磨牙远中开始向后,在每个牙根间区域（包括上颌结节）距离牙槽嵴顶2、4、6、8、10 mm处,分别测量颊舌（腭）向宽度和近远中宽度。采用SPSS 16.0软件进行单因素方差分析和LSD法比较。结果1）上颌后牙区近远中骨量在同一高度不同位置间均存在统计学差异（P<0.05）,最大近远中骨量位于第二前磨牙和第一磨牙腭侧根间;颊腭向骨量在不同位置、高度间均有统计学差异（P<0.05）,最大颊腭向骨量位于第一磨牙和第二磨牙之间。2）下颌后牙区近远中骨量在不同位置、高度间均有统计学差异（P<0.05）,颊舌向骨量在同一位置不同高度间均存在统计学差异（P<0.05）,最大近远中骨量和最大颊舌向骨量均位于第一磨牙和第二磨牙之间。结论经CBCT获取了上下颌骨后牙段植入微螺钉种植体的安全区域,为后续临床应用提供了有价值的参考。     

不同矢状骨面型患者后牙颊舌向倾斜度及Wilson曲线曲度的CBCT测量研究

目的 研究不同矢状骨面型患者的后牙颊舌向倾斜度及Wilson曲线曲度,探讨不同矢状骨面型患者的后牙水平向倾斜代偿机制,为骨性错畸形治疗中后牙倾斜度控制提供参考依据。方法 本研究已通过单位伦理委员会审查批准,并获得患者知情同意。选取90例青少年及90例成人正畸治疗前的CBCT资料作为研究对象,两组样本中各包括矢状骨面型Ⅰ类、Ⅱ类、Ⅲ类各30例。分别测量每一侧由第一前磨牙至第二磨牙的所有后牙颊舌向倾斜度、第一磨牙及第二磨牙的Wilson曲线曲度,比较不同矢状骨面型的青少年及成人间的差异。结果 与Ⅰ类骨面型成人相比,Ⅱ类骨面型成人的上颌后牙倾斜度减小,下颌后牙倾斜度增大,差异有统计学意义;Ⅲ类骨面型成人上颌后牙倾斜度增大,下颌后牙倾斜度减小,差异有统计学意义;Ⅱ类骨面型成人第二磨牙的Wilson曲线曲度显著性增大,差异有统计学意义。与Ⅰ类骨面型青少年相比,Ⅲ类骨面型青少年的上颌后牙倾斜度增大,差异有统计学意义。不同矢状骨面型青少年下颌后牙倾斜度差异无统计学意义。对比青少年与成人,Ⅱ类骨面型成人上后牙更偏舌倾,除下颌第一磨牙外下颌后牙更偏直立;Ⅲ类骨面型成人下颌后牙除下颌第二磨牙外更偏舌倾,差...     

螺旋CT评价青少年与成年人牙槽骨皮质骨密度及厚度的差异

目的:通过螺旋CT测量,评价不同年龄(青少年12～18岁,成年人19 ～48岁)、性别及位置在牙槽骨皮质骨的厚度及密度的差别.方法:对60例12 ～48周岁患者(男27例,女33例,青少年组35例,成人组25例)进行颌骨螺旋CT扫描,在12个牙根间部位测量牙槽嵴顶至14 mm高度的颊侧皮质骨厚度及灰度值.结果:上下颌骨的皮质骨厚度及密度总体趋势表现为随着距牙槽嵴顶垂直距离增大而增大.上下颌前部皮质骨厚度平均为1.0～1.5 mm.上颌后部厚度为1.1 ～1.8 mm,下颌后部为1.5 ～2.8 mm.下颌后部皮质骨厚度及密度明显高于上颌后部(P＜0.05).皮质骨厚度无明显年龄及性别差异,而青少年皮质骨密度明显低于成年人(P＜0.05).成年人下颌后部骨密度最高,而青少年时期上颌后部骨密度最低.结论:青少年皮质骨密度明显低于成年人,上颌后部最低,而成年患者的下颌后部皮质骨较厚且硬度较大.     

Comparison of cortical bone thickness and root proximity at maxillary and mandibular interradicular sites for orthodontic mini‐implant placement

Authors – Lim JE, Lee SJ, Kim YJ, Lim WH, Chun YS Objectives – To compare maxillary and mandibular cortical bone thickness and rootic proximity for optimal mini‐implant placement. Setting and Sample Population – CT images from 14 men and 14 women were used to evaluate buccal interradicular cortical bone thickness and root proximity from mesial of the central incisor to the 2nd molar. Cortical bone thickness was measured at 0°, 15°, 30°, and 45° angles relative to the root surface using three‐dimensional images. Results – For the cortical bone thickness, there was no statistically significant difference between the maxilla and the mandible in the anterior area; however, there was a significant difference in the posterior area. Cortical bone in the maxilla, mesial and distal to canine interradicular sites, was thickest while thickness in the mandible exhibited a gradual anterior to posterior increase. Cortical bone thickness in the maxilla increased as both level and angle increased, while the cortical bone thickness in the mandible was greatest at 4 mm from the alveolar crest. Root proximity mesial and distal to 2nd premolar interradicular sites was greatest. Conclusion – Based on our results, cortical bone thickness depends on the interradicular site rather than sex or individual differences.     

Evaluation of two morphometric methods of bone loss percentages caused by periodontitis in rats in different locations

Objective

The present study evaluated morphometrically bone loss percentages in experimental periodontitis in rats, comparing different locations (lingual mandible, palatal maxilla and buccal maxilla) and two evaluation methods (distance and area methods).

Material and Methods

Ligatures were placed around the maxillary right second molar and around the mandibular right first molar in 14 female Wistar rats. The contralateral molars served as intragroup controls. After 4 weeks, the rats were sacrificed and their mandible and maxilla were removed. The specimens were dissected and stained with methylene blue dye. Bone loss was evaluated by two different methods on the surfaces of the defleshed jaw. In the first method, the distance from the cementoenamel junction (CEJ) to the alveolar bone crest was measured in the roots of teeth associated with ligature. In the second method, the area of bone loss was determined using the alveolar tissue bone, CEJ and the proximal region of roots associated with the ligature as reference. The data were converted to bone loss percentages caused by ligature: (ligated – unligated) x 100/ligated.

Results

When comparing the distance and area methods, no statistically significant difference was observed (p>0.05). Both methodologies indicated that the maxilla presented greater bone loss than the mandible and it was more accentuated on the buccal side than on the palatal side (p<0.05).

Conclusion

The findings of this study show that both the area and the distance methods can be used to evaluate bone loss caused by ligature placement in rats, and suggest applying the morphometric methodology to the maxilla on the buccal side.     

Cortical bone thickness in dentate and edentulous human cadavers

BACKGROUND: A critical component of treatment planning in dental implant therapy is the amount of available bone. Thick cortical plates have been the primary way to achieve primary implant stability. However, information about cortical bone thickness in various regions of the maxilla and mandible is largely missing. Hence, it was the purpose of this cadaver study to determine an average cortical bone thickness in different tooth locations. METHODS: To determine the average thickness of buccal and lingual plates, 28 cadaver heads (68% male and 32% female) with an average age of 73.1 years were measured at various locations correlating to molar (M), premolar (PM), and anterior (A) regions. Edentulous and dentate regions also were recorded. RESULTS: Average buccal cortical thicknesses were 1.69 mm (M), 1.43 mm (PM), and 1.04 mm (A) in the edentulous maxilla; 2.06 mm (M), 1.78 mm (PM), and 1.36 mm (A) in the edentulous mandible; 2.23 mm (M), 1.62 mm (PM), and 1.59 mm (A) in the dentate maxilla; and 1.98 mm (M), 1.20 mm (PM), and 0.99 mm (A) in the dentate mandible. Average lingual cortical thicknesses were 2.06 mm (M), 1.60 mm (PM), and 1.36 mm (A) in the edentulous maxilla; 2.39 mm (M), 1.88 mm (PM), and 1.66 mm (A) in the edentulous mandible; 2.35 mm (M), 2.0 mm (PM), and 1.95 mm (A) in the dentate maxilla; and 2.51 mm (M), 1.92 mm (PM), and 1.24 mm (A) in the dentate mandible. CONCLUSIONS: The average cortical thickness of the buccal plates ranged from 1.0 to 2.1 mm in the edentulous maxilla and mandible, with the thinnest area in the anterior maxilla and the thickest area in the posterior mandible. The buccal plate of the dentate maxilla and mandible ranged from 1.6 to 2.2 mm in thickness, with the thinnest area in the lower anterior region and the thickest area in the upper posterior region.     

Cheek and tongue pressures in the molar areas and the atmospheric pressure in the palatal vault in young adults.

The pressures acting on the maxillary and mandibular posterior teeth from the tongue and cheeks were measured in 24 adults aged 22-29 years. In addition, the pressure in the palatal vault was recorded. The pressure at two maxillary (buccal and lingual) and two mandibular (buccal and lingual) measuring points, and in the palatal vault was recorded simultaneously. Repeated recordings of the pressures at rest, and during chewing and swallowing were made. The pressures at rest were of similar magnitude (about 2 g/cm2) at the buccal and lingual sides of the mandibular posterior teeth. The median resting pressure at the maxillary posterior teeth was 2.7 g/cm2 on the buccal side and 1.0 g/cm2 on the lingual side. The difference in the maxilla was significant, but not in the mandible. It was concluded that the equilibrium of tooth position is maintained by the pressure from the cheeks and the tongue. During chewing and swallowing the pressures on the lingual side of the teeth were greater than those on the buccal side. At rest about half of the subjects had a negative pressure at the palatal vault, but no correlations between the resting pressure at the palatal vault and the resting pressures on the teeth were found.     

偏颌畸形患者的牙弓特征

目的　分析偏颌畸形患者的牙弓特征,为临床矫治提供参考。方法　采用三维坐标测量仪在20例偏颌 畸形患者(试验组)和20例正常人(对照组)的牙模型上测量上下颌尖牙、前磨牙和磨牙牙尖的三维坐标值,分 析牙弓矢向和横向的对称性、上下牙弓的协调性和牙齿倾斜度,采用SAS 6·03进行统计学检验。结果　试验组上 颌尖牙和第一前磨牙距腭中缝的距离偏向侧大于偏离侧(P<0·05),下颌从尖牙到第二磨牙偏向侧距中线的距离 小于偏离侧(P<0·05);上颌尖牙和第一前磨牙的牙弓宽度比率较对照组小(P<0·05),而上颌第二前磨牙和第一 磨牙的牙弓宽度比率与正常无统计学差异(P>0·05);上颌后牙偏向侧颊向倾斜度大于偏离侧,下颌后牙偏向侧 舌向倾斜度大于偏离侧(P<0·05);上颌偏向侧和偏离侧牙齿的矢向位置无统计学差异(P>0·05)。结论　偏颌畸 形患者上牙弓前部窄于下牙弓,上颌牙齿矢向位置无差别,而上下颌两侧后牙颊舌向倾斜度存在明显差异。     

安氏Ⅱ1类错(牙合)不同骨面型的牙颌垂直向形态特征分析

目的：探讨安氏Ⅱ^1类错[牙合]不同骨面型牙颌垂直向形态特征。方法：选取恒牙初期的正常[牙合]Ⅱ^1类错[牙合]均角型、高角型、低角型的X线头颅侧位片各30张，男女各半，进行X线头影测量分析，通过多组间单因素方差分析及两两比较，明确Ⅱ^1类错[牙合]3种骨面型和正常[牙合]的牙颌垂直向形态变化。结果：（1）所有Ⅱ^1类错[牙合]总体上颌复合体的前部相对于后部垂直向发育过度。均角组上颌复合体整体相对发育过度，颅底-下颌支复合体发育不足：高角组上颌复合体前部发育过度，后部和颅底-下颌支复合体发育不足；均角组和高角组下颌有后下旋转的趋势。低角组颅底-下颌支复合体的垂直生长相对于上颌复合体的后部发育过度，上颌复合体前部发育正常。下颌有前上旋转的趋势。Ⅱ^1类错[牙合]L6的垂直高度降低，U6远中倾斜。高角组、均角组U6垂直高度未增加，功能[牙合]平面（FOP）前下倾斜．高角组U6及功能[牙合]平面倾斜的程度最大；低角组U6垂直高度降低，远中倾斜程度最小，功能[牙合]平面未见异常。结论：Ⅱ^1类错[牙合]不同骨面型牙颌形态表现出不同的垂直向特征，治疗时垂直向控制应采取不同的措施。     

Correlation between facial growth patterns and cortical bone thickness assessed with cone-beam computed tomography in young adult untreated patients

BackgroundThe vertical facial growth pattern is one of the most important issue in the orthodontic diagnosis and treatment. Previous studies investigated the association between interdental bone thickness and facial divergence using mainly bidimensional analysis. When two-dimensional dental radiographic views are not sufficient for diagnosis and measurements, cone-beam computed tomography (CBCT) images should be used to assess the alveolar bone structure three-dimensionally and with high accuracy and reliability.The aim of the present study was to evaluate the correlation between alveolar bone thickness and facial divergence in young adults untreated patients using a three-dimensional method analysis with CBCT images.MethodsRecords of 30 untreated patients (mean age 16 ± 2 years) with Angle Class I and mild to moderate crowding were analyzed. Subjects were classified as hypodivergent (<39˚), normodivergent (41 ± 2˚), and hyperdivergent (>43°). according to the inter-maxillary angle between the sagittal maxillary plane (ANS-PNS) and the mandibular plane (GN-ME). The alveolar bone thickness measurements were taken for the buccal and palatal/lingual surfaces of maxillary and mandibular anterior teeth. Axial-guided navigation (AGN) was used to locate all landmarks using a specific software (Horos 3.0).ResultsThe statistical analysis showed a significant difference between the hypodivergent and hyperdivergent group regarding buccal bone height (P = 0.005), buccal apical bone thickness (P = 0.003) and palatal mid-root bone thickness (P = 0.006). Moreover, buccal bone height (P = 0.006) was found to be statistically significant different in normodivergent compared with hypodivergent individuals.ConclusionsFacial types were found to be correlated with alveolar bone thickness. The hyperdivergent subjects presented thinner alveolus bone in the anterior maxilla and at almost all sites in the mandible. Clinicians should be aware of the possibility of thin cortical bone plates in hyperdivergent patients, reducing antero-posterior movements to avoid fenestration and dehiscence.