离体上颌第二前磨牙根管颊舌向弯曲的发生情况

目的：确定人上颌第二前磨牙的颊舌向根管弯曲程度和情况。方法：收集213个离体的上颌第二前磨牙，拍近远中向的X线片，用Photoshop5．0软件分析根管，Weine氏法测量根管的弯曲度，测量角度大于18度时，则认为根管有明显的弯曲，根管的构型采用Vertucci分类法。结果：单根单根管上颌第二前磨牙的根管弯曲仅有2个，单根双根管牙齿的根管明显弯曲有6个，在28个双根牙中有明显根管弯曲的6个，根管弯曲的牙齿总发生率为6．6％(14/213)。根管弯曲的发生部位多为根尖1/3或附近。结论：上颌第二前磨牙颊舌向根管弯曲的发生率较低。     

离体的上颌第一前磨牙的根管和牙根情况的研究

目的 :观察上颌第一前磨牙的牙根及根管形态。方法 :115个离体的上颌第一前磨牙 ,对牙齿进行近远中向X线照像 ,然后从根中 1/3横断 ,按Vertucci :分类法对根管系统进行记录。结果 :74个牙是单根 (64 % ) ,41个牙是双根 (3 6% ) ,双根牙根管均是Ⅰ型 (1) ,即每个牙均是 2个根管 ,每个根 1个根管 ,而 3 9%的单根牙是 1个根管 ,61%的单根牙有 2个根管 [Ⅱ型 (2 1) ,Ⅳ型 (2 ) ,Ⅴ型 (1 2 ) ]。结论 :上颌第一前磨牙的根管类型相对复杂。     

下颌前磨牙牙根形态和根管系统的锥形束CT研究

目的采用锥形束CT(Cone-beam computed tomography,CBCT)研究下颌前磨牙牙根及根管系统解剖形态特征。方法回顾148例患者288颗下颌第一前磨牙和218颗下颌第二前磨牙的CBCT影像,分析牙根和根管系统形态,采用Vertucci等提出的分类法对根管构型进行分类。结果 288颗下颌第一前磨牙单根牙285颗,双根牙2颗。三根牙1颗;根管Ⅰ型占77.78%,Ⅱ型0.34%,Ⅲ型2.08%,Ⅳ型0.69%,Ⅴ型14.58%,Ⅶ型1.04%,Ⅹ型0.69%,C型2.78%。218颗下颌第二前磨牙全部为单根;根管Ⅰ型占98.17%,Ⅴ型占1.83%。结论下颌前磨牙大多数是单根单根管。下颌第一前磨牙根管系统具有较大的变异性。下颌第一前磨牙多根管类型主要是Ⅴ型,C型根管的检出率也较高。而下颌第二前磨牙多根管的发生率远低于下颌第一前磨牙。多根管的分歧发生在根中或根尖1/3处。CBCT可用于下颌前磨牙复杂根管形态的评价。     

上颌前磨牙牙根及根管形态的锥形束CT研究

目的研究上颌前磨牙牙根形态、三根管的发生率和根管解剖形态,为临床诊疗提供参考。方法选取珠海市口腔医院412名患者,共779颗上颌第一前磨牙,728颗上颌第二前磨牙的锥形束CT(cone-beam computed tomography,CBCT)扫描数据,分析上颌前磨牙的牙根及根管形态,三根管的发生率、双侧对称性、根管分叉位置等。结果上颌第一前磨牙三根管发生率为1.8%,上颌第二前磨牙三根管发生率为0.3%,上颌第一前磨牙三根管发生率显著高于上颌第二前磨牙(X^2=8.304,P=0.004)。上颌第一前磨牙三根管对称率为27.3%,上颌第二前磨牙无对称三根管结构出现。上颌前磨牙解剖形态可为单根、双牙根或三牙根,其内部根管形态复杂,存在七种Vertucci根管类型,上颌第一前磨牙以VertucciⅣ型为主,上颌第二前磨牙则以VertucciⅠ型常见。三根管上颌前磨牙的根管分叉位置多见于根中或根上1/3,16颗三根管上颌前磨牙都具有三个独立的根尖孔。结论上颌前磨牙根管形态复杂多变,CBCT对发现变异和额外根管具有重要辅助作用。     

上颌第二前磨牙根管峡发生率和位置的研究

目的：研究离体单根的上颌第二前磨牙根尖1—6mm处根管形态及根管峡部的发生率和位置的情况。方法：收集离体上颌第二前磨牙60颗，自根尖开始，片切去除1mm牙根后，用美蓝染色根切面，在显微镜下观察并记录各横截面的根管数和峡部分布情况。在距根尖1～6mm区域内每隔1mm处重复以上操作。结果：上颌第二前磨牙双根管率是41．67％；根管峡部在距根尖4mm水平最高。结论：上颌第二前磨牙根管峡部在距根尖3—5mm区最高发；根尖1～6mm区域根管系统形态复杂。     

中国人群上颌磨牙近中颊根根管形态研究

目的：研究中国人群中上颌磨牙近中颊根根管的解剖形态。方法：选取138颗离体上颌磨牙，截去牙冠，完全暴露髓室底，用08＃号K锉疏通近中颊根MB及MB2至根尖孔，并扩大至15＃号，对单根管但存在两个根尖孔的牙齿，从根尖孔方向用08＃号K锉逆行通畅根管，术前术后分别用数字X线机从近远中方向和颊腭向行诊断丝平行投照。结果：在138颗离体牙中除了2颗因根管钙化近中颊根MB不能完全用08＃号K锉疏通，其余136颗离体牙中近中颊根Ⅰ型根管有47颗（34.6％）、Ⅱ型根管有46颗（33.8％）、Ⅲ型根管有28颗（20.6％）、Ⅳ型根管有9颗（5.8％）、Ⅴ型根管有6颗（4.4％）。结论：中国人群中上颌第一、第二磨牙近中颊根双根管发生率为65.4％。提示上颌磨牙近中颊根MB2发生率很高，因此掌握其解剖形态对临床完善治疗有着重要的意义。     

上颌第一前磨牙根管形态的锥形束CT研究

目的利用CBCT评估上颌第一前磨牙根管解剖形态。方法收集因种植手术前评估,正畸治疗前评估,复杂疑难根管治疗等原因拍摄的CBCT 710例,根据样本纳入标准得到404例双侧CBCT图像,记录患者的姓名,性别,年龄,牙位,牙根和根管数目,牙根弯曲方向和根分叉的位置。结果上颌第一前磨牙以单根牙和多根牙多见,三根牙最少见,单根牙发生率为65.1%,双根牙发生率为34.7%,三根牙发生率为0.2%,有2例左侧颊根分为两根,为三根牙。单根牙和双根牙在男女性别间的发生率无统计学差异,根管类型中14.7%有1个根管为Ⅰ(1-1)型,85.1%为复杂的两根管类型(Ⅱ型到Ⅶ型及2-1-2-1型),只有0.2%有三根管为Ⅷ型。上颌第一前磨牙牙根弯曲的发生率为38.1%。根据弯曲方向分为5种类型,颊侧弯曲22.7%,舌侧弯曲17.3%,近中弯曲11.6%,远中弯曲42.1%,S形弯曲6.2%。上颌第一前磨牙牙根分叉的发生率为34.9%,根据分叉的部位分为根冠1/3、根中1/3、根尖1/3分叉,发生率为31.6%,44.7%,23.8%。结论上颌第一前磨牙多为单根牙,而且多为单根牙双根管,单根牙的根管形态多样,牙根多向远中弯曲,牙根分叉位于牙根中段。     

上颌第二磨牙近颊根根管形态的研究

目的:运用透明牙技术研究上颌第二磨牙近颊根根管形态。方法:收集离体上颌第二磨牙70颗,先去除牙髓,根管内注入印度墨水,经10%硝酸脱钙,酒精梯度脱水,于99%水杨酸甲酯中透明,在放大镜下观察根管形态,按Vertucci标准对根管分类。结果:70颗上颌第二磨牙中67颗为三根牙,占95.71%。67颗三根牙的腭根和远颊根均为单根管,近颊根单根管率为55.22%。70颗上颌第二磨牙中,近颊第二根管(MB2)的发生率为42.86%,其根管类型以Ⅱ型(2-1)和Ⅳ型(2-2)为主。结论:上颌第二磨牙近颊根根管形态复杂,对其解剖形态熟练掌握,能够提高该牙根管治疗的成功率。     

422颗上颌第一前磨牙牙根及根管解剖形态的观察

目的:了解上颌第一前磨牙的牙根和根管形态,为临床治疗提供解剖学依据.方法:收集422颗上颌第一前磨牙.按性别分组,统计分析各牙根形态出现率;采用透明牙技术观察分析根管形态,根据Vertucci分类法,统计分析各根管形态的出现率;采用SPSS11.5软件包对数据进行X2检验.结果:(1)422颗标本中,单根牙占57.36%,双根牙占41.47%.三根牙占1.18%.男性组分别为33.58%、62.68%和3.73%.女性组分别为66.67%、33.33%.没有三根牙.2组间有显著性别差异(P＜0.01).(2)415颗透明牙标本中,共观察到9种根管形态.Ⅰ型占10.12%,Ⅱ型占10.60%,Ⅲ型占6.02%.Ⅳ型占56.63%,Ⅴ型占12.05%,Ⅵ型占1.93%.Ⅶ型占0.72%,Ⅷ型占1.45%,Ⅸ型占0.48%.单根管(Ⅰ型)占10.12%.双根管(Ⅱ-Ⅶ型)占87.95%,三根管(Ⅷ,Ⅸ型)占1.93%.结论:上颌第一前磨牙牙根形态多样并有显著性别差异.而且根管形态类型复杂.充分了解其解剖形态.对临床治疗具有重要意义.     

上颌第一前磨牙根管系统研究

目的：制作上颌第一前磨牙离体牙透明标本，研究其根管系统解剖形态。方法：100颗上颌第一前磨牙经透明髓腔处理后，直接在体视显微镜下读取根管系统的形态并作规律性统计处理。结果：①上颌第一前磨牙根管口分为单、双两种类型，②主根管形态以2－2型、1－1型和2－1型常见，③侧副管发生率高，根管侧枝和根尖区的细小分支均高达14％，而且伴随双根管出现的管间交通也高达9％。结论：上颌第一前磨牙的根管治疗效果不确定性较大。     

Soft-tissue stretching: a possible control factor in craniofacial morphogenesis

abstract – A hypothesis is presented which links posturally induced stretching of the facial soft-tissue layer, craniofacial morphology and airway adequacy into a suggested cycle of factors related to craniofacial morphogenesis.     

离体下颌前磨牙根管及牙根形态研究

目的 :研究离体下颌前磨牙的牙根及根管形态。方法 :观察并记录 69个离体下颌第一前磨牙及 93个下颌第二前磨牙牙根的基本形态 ,对牙齿进行近远中向X线摄片 ,当X线片上显示疑问根管时 ,分别从根中 1/3 ,根尖 1/ 3横断 ,确定根管的类型 ,按Vertucci’s分类法对根管系统进行记录。结果 :所收集的下颌前磨牙均为单根 ,其中大多数下颌第一前磨牙的根管类型是I型 ( 1) ,93个下颌第二前磨牙的根管均为I型 ( 1) ,下颌第一前磨牙的根面沟发生率较高 ( 15 / 69) ,且此类型的下颌第一前磨牙常有双根管 ,主要是V型 ( 1-2 ) ,下颌第二前磨牙的根面沟发生率相对较低 ( 5 / 93 )。结论 :当X线片上显示下颌第一前磨牙的异常影像时 ,应进行详细的X线检查和髓腔探查 ,避免误判或治疗时遗漏根管。     

Number of roots and canals in maxillary first premolars: study of an Andalusian population

Abstract— A study of 150 extracted maxillary first premolars from citizens of Seville, Andalusia, southern Spain, revealed 60 teeth with one root (40.0%), 85 teeth with two roots (56.7%) and five teeth with three roots (3.3%). The distribution of root canal shapes in the sample showed that all teeth with two or three roots had type I root canals (each canal had one apical foramen). Conversely, most of the single-rooted maxillary first premolars had root canal shape type II (two canals converging in the same apical foramen). Only 1.3% of the teeth had a unique orifice in the pulp chamber and only one root canal. These results emphasized the importance of good knowledge of the root canal morphology and the need for a careful radiographic examination as part of competent root canal therapy of maxillary first premolars.     

Root and canal morphology of maxillary premolars and their relationship with the crown morphology

ObjectivesTo investigate the relationship between crown/root size and root/canal morphology of maxillary premolars.MethodsOne hundred and thirty-three first (P1) and 110 second (P2) maxillary premolars were used. Mesiodistal and buccolingual diameters and root heights of P1 and P2 were recorded to the nearest 0.01 mm. The number of single and multi-rooted premolars was recorded based on the Turner's classification. Root canal morphology was studied using a clearing technique with Vertucci's classification. Pearson's correlation coefficient was used to analyze the relationship between tooth size and root/canal morphology.ResultsTwo-rooted P1 was found in 33.9% of male and 22.5% of female. P2 showed a single root in 85.4% of male and 82.6% of female. In case of P1, the number of root canals (P<0.05) and apical foramina (P<0.01) was significantly different between male and female. P1 crown dimensions were larger in double-rooted teeth than in single-rooted ones. Significant differences were observed in buccolingual (P<0.05) and crown area (P<0.05) in females. Root height was smaller in double-rooted than in single-rooted P1. A similar trend was observed for P2 with a larger crown size in teeth with two apical foramina compared with those with a single foramen.ConclusionsTwo-rooted P1 with two or more apical foramina are more commonly seen in males than in females. For P1, the correlation of number of roots and apical foramina was stronger with buccolingual diameter than with mesiodistal diameter in both genders. P1 and P2 with large crown dimensions tend to have multiple roots and apical foramina.     

Ethnic differences in craniofacial and upper spine morphology in children with skeletal Class II malocclusion

Objectives:To analyze differences in upper cervical spine and craniofacial morphology, including posterior cranial fossa and growth prediction signs, between Danish and South Korean pre-orthodontic skeletal Class II children and to analyze associations between upper cervical spine morphology and craniofacial characteristics.Materials and Methods:One hundred forty-six skeletal Class II children—93 Danes (54 boys and 39 girls, mean age 12.2 years) and 53 Koreans (27 boys and 26 girls, mean age 10.8 years)—were included. Upper spine morphology, Atlas dimensions, and craniofacial morphology, including posterior cranial fossa and growth prediction signs, were assessed on lateral cephalograms. Differences and associations were analyzed by multiple linear and logistic regression analyses adjusted for age and gender.Results:Significant differences between the ethnic groups were found in the sagittal and vertical craniofacial dimensions (P < .001), mandibular shape (P < .01), dental relationship (P < .01), posterior cranial fossa (P < .05), and growth prediction signs (P < .001). No significant differences were found in upper spine morphology and Atlas dimensions between the groups. Upper spine morphology/dimensions were significantly associated with the cranial base angle (P < .01), sagittal craniofacial dimensions (P < .001), posterior cranial fossa (P < .001), and growth prediction signs (P < .05).Conclusions:Upper spine morphology/dimensions may be valuable as predictive factors in treatment planning for growing Class II children.     

上颌第三磨牙的形态观察

目的 探讨上颌第三磨牙牙尖数目与牙根型、牙根型与根管数目间的关系,为上颌第三磨牙的保留和再利用提供参考。方法 利用电子数显游标卡尺对上颌第三磨牙进行测量分析,观察牙尖数目和牙根的关系,并通过透明标本的制作观察其髓腔形态。结果 上颌第三磨牙根长大于冠长,颊舌径大于近远中径。其（牙合）面以三尖型居多,其次是四尖型。二尖型和三尖型融合根比例大,四尖型和五尖型者,则二根比例较大。根管系统虽较为复杂,但主要是双根管和三根管型。结论 上颌第三磨牙牙尖与牙根、牙根与根管间的关系有一定的规律性。?     

Craniofacial and pharyngeal airway morphology in patients with acromegaly

Abstract

Objective. The aim of this study was to assess differences in craniofacial characteristics, upper spine and pharyngeal airway morphology in patients with acromegaly compared with healthy individuals. Materials and methods. Twenty-one patients with acromegaly were compared with 22 controls by linear and angular measurements on cephalograms. The differences between the mean values of cephalometric parameters were analyzed with Mann-Whitney U-test. Results. With respect to controls, anterior (p < 0.05), middle (p < 0.01) and posterior (p < 0.05) cranial base lengths were increased, sella turcica was enlarged (p < 0.001) and upper spine morphology demonstrated differences in the height of atlas (p < 0.01) and axis (p < 0.05) in patients with acromegaly. Craniofacial changes were predominantly found in the frontal bone (p < 0.01) and the mandible (p < 0.05). As for the airway, patients with acromegaly exhibited diminished dimensions at nasal (p < 0.001), uvular (p < 0.01), mandibular (p < 0.01) pharyngeal levels and at the narrowest point of the pharyngeal airway space (p < 0.001) compared to healthy controls. Soft palate width was significantly higher (p < 0.001) and the hyoid bone was more vertically positioned (p < 0.01) in patients with acromegaly. Conclusions. Current results point to the importance of the reduced airway dimensions and that dentists and/or orthodontists should be aware of the cranial or dental abnormalities in patients with acromegaly.     

Tooth agenesis and craniofacial morphology in pre-orthodontic children with and without morphological deviations in the upper cervical spine

AIM: To analyze differences in prevalence and pattern of tooth agenesis and craniofacial morphology between non syndromic children with tooth agenesis with and without upper cervical spine morphological deviations and to analyze associations between craniofacial morphology and tooth agenesis in the two groups together. METHODS: One hundred and twenty-six pre-orthodontic children with tooth agenesis were divided into two groups with (19 children, mean age 11.9) and without (107 children, mean age 11.4) upper spine morphological deviations. Visual assessment of upper spine morphology and measurements of craniofacial morphology were performed on lateral cephalograms. Tooth agenesis was evaluated from orthopantomograms. RESULTS: No significant differences in tooth agenesis and craniofacial morphology were found between children with and without upper spine morphological deviations (2.2 ± 1.6 vs 1.94 ± 1.2, P > 0.05) but a tendency to a different tooth agenesis pattern were seen in children with morphological deviations in the upper spine. In the total group tooth agenesis was associated with the cranial base angle (n-s-ba, r = 0.23, P < 0.01), jaw angle (ML/RLar, r = 0.19, P < 0.05), mandibular inclination (NSL/ML, r = -0.21, P < 0.05), mandibular prognathia (s-n-pg, r = 0.25, P < 0.01), sagittal jaw relationship (ss-n-pg, r = -0.23, P < 0.5), overjet (r = -0.23, P < 0.05) and overbite (r = -0.25, P < 0.01). CONCLUSION: Etiology of tooth agenesis in children with upper spine morphological deviations was discussed. The results may be valuable for the early diagnosis and treatment planning of non syndromic children with tooth agenesis.     

Furcation topography of the maxillary and mandibular first molars

The objective of the present study was to describe the topography of the furcation area of the maxillary and mandibular first molars. By using a photogrammetric method, the furcation areas of extracted teeth were plotted to obtain 3-dimensional contour maps. By comparing the individual 10 drawings of the maxillary and mandibular first molars, respectively, some morphological characteristics of the furcation areas could be described. Accordingly, the study showed the complexity of the furcation areas with presence of a number of small ridges, peaks and pits forming a mixture of convexities and concavities.