正常牙合青年牙冠唇颊面中心区轮廓研究

探讨预成序列托槽底板形态、粘接区域牙面轮廓及两者贴合度对直丝弓矫治技术的影响.运用精密轮廓仪测量四川地区青年60副正常牙合模型牙冠表面1纵3横4条曲线,获取前牙及双尖牙临床牙冠表面中心区的轮廓特征.结果显示牙冠唇颊面中心区垂直方向从切牙至双尖牙逐渐变凸,水平方向凸度尖牙唇面近中大于远中;同名牙形态不同个体间存在较大差异. 结论同名牙临床牙冠中心4 mm×3 mm区域形态较为稳定,适合托槽定位;托槽垂直向移位可引起既定转矩值的改变,尖牙托槽底板弧度应有近远中之分.     

透明矫治器压低下前牙的生物力学分析

目的 探索透明矫治器压低下前牙过程中牙齿唇舌向倾斜度的变化规律及相应的生物力学机制,获得牙齿垂直压低过程中的唇舌向控制策略。 方法 建立透明矫治器垂直压低下前牙的仿真模型,设计不同切牙下颌平面角度(incisor mandibular plane angle,IMPA),设置常规组、唇侧压低附件组、唇侧控根嵴组及舌侧控根嵴组,分析下 前牙的位移趋势及唇舌向力矩。 结果 在下前牙压低中,IMPA<90°时牙冠受到舌向力矩;IMPA>90°时,牙冠受到唇向力矩。 牙冠部添加唇侧控根嵴可以增加牙冠唇向转矩趋势,添加舌侧控根嵴及唇侧附件增加牙冠舌向转矩趋势。 结论 透明矫治器压低下前牙中会出现牙冠非设计性的唇舌向移动。 牙冠唇倾时,可以设计舌侧控根嵴来避免牙冠唇向移动;牙冠舌倾时,可以设计唇侧控根嵴来避免牙冠舌向移动。     

骨性Ⅲ类错牙合体分段长轴倾斜方向的一致性评价

目的通过分段测量骨性Ⅲ类错牙合畸形患者上下牙列牙弓内所有牙齿(除第三磨牙)的轴倾角和转矩角,评价牙冠、牙根及全牙位置指标间的关系。方法选取符合纳入标准的29例成人骨性Ⅲ类错牙合患者,拍摄CBCT并收集其Dicom数据,利用Invivo5.1软件对上、下颌各牙的牙冠、牙根、全牙的转矩角和轴倾角进行测量。结果 (1)骨性Ⅲ类错牙合,上、下牙列冠、根及全牙轴倾角一致性较好,两两比较,P0.05。(2)骨性III类错牙合,在全牙列的转矩角中,上牙列冠、根及全牙的一致性较好,两两比较,P0.05,而下牙列除磨牙外所有牙齿冠、根倾斜存在统计学差异,P0.05,牙根与牙体长轴方向及程度较一致,差异无统计学差异,P0.05。结论 (1)骨性Ⅲ类错牙合牙冠的倾斜角度与牙根或全牙的倾斜角度的一致性不高,可能存在牙体位置判别误差;(2)牙根倾斜程度与全牙倾斜程度较一致。     

高角骨性Ⅲ类错牙合牙齿倾斜位置特征

目的　了解高角Ⅲ类错牙合 畸形患者全牙轴倾及转矩特征,以期为临床治疗提供指导。 方法　收集符合纳入标准的高角骨性I类（13名）及Ⅲ类（11名）错牙合 畸形共计24名患者头颅CBCT影像Dicom数据,利用invivo 5.1软件进行全牙轴倾度及转矩测量。 结果　（1）高角I类及Ⅲ类左右同名牙倾斜度一致性较好,P＞0.05,此后左右同名牙数据一并处理。（2）高角Ⅲ类与I类矢状向比较：①高角Ⅲ类,上前牙根舌向转矩增大趋势,但仅在上尖牙表现统计学差异,P＜0.05;②高角Ⅲ类,下前牙根舌向转矩减小,P<0.05,差异有统计学意义;③ 高角Ⅲ类,上后牙近中轴倾、下后牙远中轴倾趋势,但差异无统计学意义,P>0.05。（3）高角Ⅲ类与I类横向比较：①高角Ⅲ类,上前牙远中轴倾增加,差异有统计学意义;下前牙轴倾变化趋势不明,仅下中切牙表现远中轴倾（P<0.05）;② 高角Ⅲ类,上后牙根舌向转矩增大,有统计学差异;下后牙根舌向转矩减小趋势,但差异无统计学意义。（4） 高角I类及Ⅲ类与Andrews正常牙合 矢状向及冠状向各牙倾斜位置比较：① 矢状向：高角I类Ⅲ类上下前牙根舌向转矩增大,上下后牙明显近中倾斜;② 冠状向：高角I类Ⅲ类上下前牙远中倾斜增大,上下后牙根舌向转矩加大。 结论　（1）高角骨性Ⅲ类牙齿位置在垂直方向的代偿表现强于矢状方向;（2）高角骨性Ⅲ类上下前牙唇舌向倾斜移动风险较高,移动时更应注重牙齿的整体移动;（3）高角骨性Ⅲ类上颌后牙明显颊向倾斜,上牙列横向扩展范围减小,扩弓后稳定性可能降低。     

高角骨性Ⅲ类错牙合牙齿倾斜位置特征

目的　了解高角Ⅲ类错牙合 畸形患者全牙轴倾及转矩特征,以期为临床治疗提供指导。 方法　收集符合纳入标准的高角骨性I类（13名）及Ⅲ类（11名）错牙合 畸形共计24名患者头颅CBCT影像Dicom数据,利用invivo 5.1软件进行全牙轴倾度及转矩测量。 结果　（1）高角I类及Ⅲ类左右同名牙倾斜度一致性较好,P＞0.05,此后左右同名牙数据一并处理。（2）高角Ⅲ类与I类矢状向比较：①高角Ⅲ类,上前牙根舌向转矩增大趋势,但仅在上尖牙表现统计学差异,P＜0.05;②高角Ⅲ类,下前牙根舌向转矩减小,P<0.05,差异有统计学意义;③ 高角Ⅲ类,上后牙近中轴倾、下后牙远中轴倾趋势,但差异无统计学意义,P>0.05。（3）高角Ⅲ类与I类横向比较：①高角Ⅲ类,上前牙远中轴倾增加,差异有统计学意义;下前牙轴倾变化趋势不明,仅下中切牙表现远中轴倾（P<0.05）;② 高角Ⅲ类,上后牙根舌向转矩增大,有统计学差异;下后牙根舌向转矩减小趋势,但差异无统计学意义。（4） 高角I类及Ⅲ类与Andrews正常牙合 矢状向及冠状向各牙倾斜位置比较：① 矢状向：高角I类Ⅲ类上下前牙根舌向转矩增大,上下后牙明显近中倾斜;② 冠状向：高角I类Ⅲ类上下前牙远中倾斜增大,上下后牙根舌向转矩加大。 结论　（1）高角骨性Ⅲ类牙齿位置在垂直方向的代偿表现强于矢状方向;（2）高角骨性Ⅲ类上下前牙唇舌向倾斜移动风险较高,移动时更应注重牙齿的整体移动;（3）高角骨性Ⅲ类上颌后牙明显颊向倾斜,上牙列横向扩展范围减小,扩弓后稳定性可能降低。     

胎儿牙齿硬组织发育的临床应用解剖

目的：探讨国人胎儿牙齿硬组织发育状况。方法：对正常胎龄10-38周的胎儿上、下颌骨作连续切片,观察乳、恒牙胚及其相关结构发生规律。结果：牙体硬组织形成于14-20周,牙齿的增殖、钙化、萌出同时进行,牙釉质、牙本质厚度随胎龄增长而增加,各乳磨牙牙尖总是近颊尖最先发牛,恒牙板总是位于乳牙胚舌侧。结论：国人牙体硬组织发育成熟较低,牙釉质、牙本质厚度与胎龄呈正相关。     

光固化树脂材料充填上颌前牙过大间隙

背景：光固化树脂是一种新型材料,具有色泽美观、强度高、应用广泛、操作简便且价廉等特点。修复时不磨牙或少磨牙,患者乐于接受。 目的：观察光固化树脂充填上颌前牙过大间隙的效果。 方法：共收治32例患者,75个上颌大间隙,107颗牙齿;其中男15例,女17例;年龄21-52岁;牙位分别为双侧中切牙1个间隙,14例;双侧中切牙、左侧侧切牙、左尖牙3个间隙,3例;双侧中切牙、右侧侧切牙、右侧尖牙3个间隙,2例;左侧中切牙、侧切牙、尖牙和右侧中切牙、侧切牙4个间隙,3例;双侧中切牙和侧切牙3个间隙,6例;左侧中切牙、侧切牙和右侧中切牙、侧切牙、尖牙4个间隙,4例。均采用光固化树脂充填过大上颌前牙间隙。随访观察牙冠形态,密合度、颜色、磨损程度及松动度情况。 结果与结论：随访3年,32例患者中修复成功17例,树脂修得的牙冠形态及密合度良好,修复体不松动脱落,无任何变色;修复基本成功9例,修复的牙冠形态及密合度欠佳,修复体不松动脱落,但在龈缘处和牙体接触处修复体有缺陷,有轻度变色;修复失败6例,牙冠形态及密合度较差,修复体松动或脱落,修复体严重变色,需要重新修复。     

上颌对称性多生前磨牙1例

患者,男,29岁,2006年12月24日因上颌腭部多生牙影响舌在口腔内活动度,要求治疗。检查:右侧上颌第一前磨牙与第二前磨牙间腭侧有一多生牙,左侧第一磨牙与第二磨牙间颊侧有一多生牙,双侧多生牙牙冠形态与第一前磨牙完全相同,并影响功能,在麻醉下拔除双侧上颌多生牙。     

替牙期前牙反(牙合)患者治疗后口周力分布变化的研究

测量替牙期前牙反(牙合)患者治疗前后口周力的分布情况,为替牙期前牙反(牙合)的预防和临床治疗提供理论依据.临床选取30名替牙期前牙反(牙合)患者,年龄8岁～12岁,平均年龄10.8岁,其中男性15名,女性15名,测量其治疗前后姿势位时上、下中切牙区唇、舌侧,左右上、下第一前磨牙区颊舌侧,左右上、下第一磨牙区颊舌侧口周力值,分析姿势位时受试者牙弓周围口周力分布变化的情况及规律.治疗前后受试者口周力各区域的分布规律基本一致;值得注意的是治疗后下切牙舌侧不再存在负压现象;治疗前后上中切牙区口周力测量值存在着显著的差异(P＜0.05).口周肌肉等软组织具有适应硬组织改变的功能,随着硬组织结构的改变,口周软组织通过发生相应的变化来维持口颌系统原有平衡、稳定状态.     

成人牙根唇舌侧牙槽骨的厚度

背景：牙根在牙槽骨的位置及周围骨板厚度影响着口腔治疗,治疗过程中如果对牙齿控制不当可造成医源性并发症。以往对颌骨的研究主要针对解剖学、骨厚度或骨密度,对于牙根在牙槽骨内的空间位置及其与周围骨骼的关系,研究关注较少。 目的：建立颌骨的数字化计算机三维模型,测量牙根的唇舌侧牙槽骨厚度。 方法：选择牙列完整无明显骨骼吸收的年轻成人70例,采用牙科专用锥形束CT机进行颌面部扫描,将扫描中采集的容积信息传入计算机工作站,以及冠状位或矢状位多平面重建,获得高质量的重建图像,原始数据以DICOM格式导入计算机,并输出到整合的3D设计软件Invivo5软件进行测量。 结果与结论：重建的颌骨数字化模型可从多平面进行观察及测量,实验测得70 例患者各个牙根唇舌侧牙槽骨厚度的均值：上下前牙舌侧牙槽骨厚度大于唇侧(P < 0.05);除上前磨牙的牙颈部唇侧牙槽骨较厚外, 其他前磨牙舌侧牙槽骨厚度大于唇侧(P < 0.05);上磨牙和下颌第一磨牙唇舌侧牙槽骨厚度接近,下第二磨牙唇侧牙槽骨厚度大于舌侧(P < 0.01)。结果证实,成人不同牙位的唇舌侧牙槽骨厚度差异较大。     

Distribution of interglobular dentine in human tooth roots

The present study was designed to examine the distribution of interglobular dentine in human tooth roots. The material comprised 17 teeth, of which 3 were premolars extracted for orthodontic reasons from children 10-12 years of age and the other teeth (4 incisors, 3 canines and 7 molars) were extracted for periodontitis from individuals aged 32-63 years. All teeth were free of caries and cervical dentine defects. Ground sections of the teeth cut longitudinally were stained with basic fuchsin and observed by fluorescence and confocal microscopy as well as transmitted light microscopy. Basic fuchsin stained the dentinal tubules, interglobular dentine and the granular layer of Tomes. These structures appeared intense blue to faint violet with transmitted light microscopy, whereas their staining displayed intense fluorescence with fluorescence microscopy. Therefore, the interglobular dentine could be detected more sensitively with fluorescence and confocal microscopy than with transmitted light microscopy. Typical interglobular dentine was present in coronal dentine in most of the teeth. In the radicular dentin, position and size of the interglobular dentine was different among the teeth examined. Most of the teeth had the interglobular dentine in the cervical part of the roots (type A). Two premolars displayed the interglobular dentine in the coronal half of the root (type B). The types A and B contained large interglobular areas. A small amount of interglobular dentine was restricted to the apical half of the roots of two canines and one molar (type C). In contrast to types A and B which were seen at both labial or buccal and lingual sides of roots, the interglobular dentine of type C was seen only at one side, labial or lingual. Some of the tooth roots did not show any interglobular dentine (type D). Most of the incisors, canines and premolar were types A, B, and C, respectively, and the molars were mixed types A, C, and D. These results suggest that the factors affecting dentinogenesis during root formation are unique for each tooth.     

Kabuki syndrome: description of dental findings in 8 patients

The cardinal features of Kabuki (Niikawa-Kuroki) syndrome (KS) include characteristic facial dysmorphic features, mild to moderate mental deficiency, skeletal abnormalities, dermatoglyphic abnormalities, and postnatal growth retardation. We identified 8 patients with KS in a genetics clinic over the past 5 years. All were Caucasians, except for 2 who were of mixed Aboriginal and Caucasian descent. All had the facial gestalt, the dermatoglyphic abnormalities characteristic of the syndrome, and developmental delay. Dental abnormalities of permanent teeth were seen in all 8 cases; 6 had missing lower incisors. Five patients had uniquely abnormal upper incisor teeth shape; the upper incisors had a 'flat head' screwdriver-shaped appearance. Other dental abnormalities included missing lower lateral incisors, missing second premolars, and ectopic upper 6-year molars. We believe the presence of the unique dental findings will prove useful in the diagnostic assessment of individuals with KS.     

Tooth homology in mammals

The development of the chewing, lacerative and omnivorous dentition type was confirmed on the base of the author's studies on the dentition of placentalia representatives. The use of vegetable food by the rodents and herbivorous mammals induces an efficient development of molars, absence or reduced number of incisors and canines of the upper jaw and increased number of incisors and absence of canines of the lower jaw, resulting into the proposal of an alteration of the dentition formula for rabbits and for the rest of the rodents (Simplicidentata), for herbivorous and for horses. In beasts of prey, besides the efficient development of the canines, a transition of the premolars and certain molars into laceratives is found. In omnivorous mammals, together with the efficient development of canines, an efficient development of molars and premolars as chewing teeth is also established.     

Presence of enamel on the incisors of the llama (Lama glama) and alpaca (Lama pacos)

Attempts have been made to define the relationships among the South American camelids, the guanaco, llama, alpaca, and vicuna, by comparing the morphology of their incisors. The alpaca has been reported to have an incisor morphology similar to the vicuna, lacking enamel on the lingual surface. The llama and guanaco are said to have enamel on both the labial and lingual surface of their incisor teeth. These comparisons have been based on gross morphological observations and not on histologic analysis. This study was undertaken to determine whether or not alpaca teeth have enamel on the lingual surface. The cross-sectional histologic anatomy of the incisor teeth was compared in two closely related South American camelid species, the llama (Lama glama), and the alpaca (Lama pacos). Thick sections (300 μm) and scanning electron microscopy were the techniques utilized. The mandibular first, second, and third incisors were examined in four llamas and five alpacas. A substantial layer of enamel was present on all surfaces of all llama incisors. The enamel layer on the labial surface of the alpaca incisors closely resembled that found in the llama. The enamel layer on the lingual surface of the alpaca incisors, although greatly reduced, was distinctly present. Alpacas may be more closely related to guanacos and llamas than to vicunas. A histologic study of vicuna incisors would help to better define the relationships of the four camelids. Anat Rec. 249:441–449, 1997. © 1997 Wiley-Liss, Inc.     

转矩作用对微植体矫治力系内收上前牙影响的三维有限元研究

目的研究转矩力的作用对于微植体矫治力系内收上前牙的影响。方法利用MIMICS软件和有限元软件ABAQUS,建立微植体矫治力系的有限元模型,并在该模型上计算分析有无转矩及转矩作用区域对中切牙和侧切牙移动趋势的影响。结果不加转矩时,中切牙和侧切牙都表现出舌向倾斜的趋势。在100g·cm转矩力的作用下,随着转矩作用区域的增大,中切牙的唇向移动趋势逐渐减小,侧切牙由舌向移动逐渐转为唇向移动。结论转矩能够有效改变牙齿的移动方式,如果转矩从中切牙之间开始向两侧远中方向逐渐减少,效果会更好。     

Odontoblast processes of the mouse incisor are plates oriented in the direction of growth

Odontoblast processes are thin cytoplasmic projections that extend from the cell body at the periphery of the pulp toward the dentin-enamel junction. The odontoblast processes function in the secretion, assembly and mineralization of dentin during development, participate in mechanosensation, and aid in dentin repair in mature teeth. Because they are small and densely arranged, their three-dimensional organization is not well documented. To gain further insight into how odontoblast processes contribute to odontogenesis, we used serial section electron microscopy and three-dimensional reconstructions to examine these processes in the predentin region of mouse molars and incisors. In molars, the odontoblast processes are tubular with a diameter of ~1.8 μm. The odontoblast processes near the incisor tip are similarly shaped, but those midway between the tip and apex are shaped like plates. The plates are radially aligned and longitudinally oriented with respect to the growth axis of the incisor. The thickness of the plates is approximately the same as the diameter of molar odontoblast processes. The plates have an irregular edge; the average ratio of width (midway in the predentin) to thickness is 2.3 on the labial side and 3.6 on the lingual side. The plate geometry seems likely to be related to the continuous growth of the incisor and may provide a clue as to the mechanisms by which the odontoblast processes are involved in tooth development.     

Evolution and development of the mammalian dentition: Insights from the marsupial Monodelphis domestica

To understand developmental mechanisms of evolutionary change, we must first know how different morphologies form. The vast majority of our knowledge on the developmental genetics of tooth formation derives from studies in mice, which have relatively derived mammalian dentitions. The marsupial Monodelphis domestica has a more plesiomorphic heterodont dentition with incisors, canines, premolars, and molars on both the upper and the lower jaws, and a deciduous premolar. The complexity of the M. domestica dentition ranges from simple, unicusped incisors to conical, sharp canines to multicusped molars. We examine the development of the teeth in M. domestica, with a specific focus on the enamel knot, a signaling center in the embryonic tooth that controls shape. We show that the tooth germs of M. domestica express fibroblast growth factor (FGF) genes and Sprouty genes in a manner similar to wild‐type mouse molar germs, but with a few key differences. Developmental Dynamics, 2011. © 2010 Wiley‐Liss, Inc.