利用曲面断层片进行下颌骨测量的研究

目的 评价利用曲面断层片进行下颌骨测量的可行性.方法 分别测量51 例患者的曲面断层片和头颅侧位片上的下颌角、下颌升支长、下颌体长、下颌综合长几项指标,分析其相关性.结果 下颌角、下颌升支长、下颌体长度、下颌综合长的测量值在曲面断层片上与头颅侧位片上的相应指标呈显著相关.结论 在统一拍摄条件下,曲面断层片能够用做下颌骨的测量.     

曲面断层片和头颅后前位片诊断下颌骨不对称的可行性探讨

目的:探讨曲面断层片和头颅后前位片在分析下颌不对称畸形中的作用。方法:人头颅骨标本5具,常规方法分别拍摄有钢珠标志和无钢珠标志的头颅标本的X线后前位定位片(PAC)和曲面断层片(Pa)。选取25例下颌不对称畸形患者的PAC和Pa。分别测量颅骨标本实体、颅骨标本的PAC和Pa、以及患者的PAC和Pa中的髁突长、下颌升支长和下颌体长。对颅骨标本测量项目的实际值和相应的影像测量值进行相关性检验,比较25例患者PAC和Pa的相应测量值的差异指数,用图表观察不同测量者测量同一样本所得测量结果的离散度。结果:当颅骨标本有钢珠标志时,其大部分影像测量值与实际值显示很强的相关性(0.96～0.99,P<0.01)。当颅骨标本无钢珠标志时,Pa测量的髁突长和下颌升支长与实际值有很强的相关性,PAC所测下颌升支长和下颌体长与实际值的相关性降低,髁突长无法测量。不同测量者测量下颌升支长时,在Pa所测的可重复性要比在PAC所测者高,测量下颌体长时,在PAC所测的可重复性则比在Pa高。结论:PAC对评价下颌骨水平向不对称较有价值,对评价下颌骨垂直向不对称的作用有限;Pa对评价下颌骨水平向不对称的价值不高,但对评价下颌骨垂直向不对称有确切的意义。     

全颌曲面断层片评价影响第三磨牙萌出因素的研究

目的：探讨应用全颌曲面断层片分析第三磨牙萌出影响因素与头颅侧位片评价的相关性，拓展全颌曲面断层片在121腔正畸临床中的应用。方法：选择39例（男21例，女18例）上下颌第三磨牙均存在的安氏Ⅰ类病例，同期拍摄全颌曲面断层片和头颅侧位片，分别测量11项指标，将两种方法测量结果进行相关性分析。结果：全颌曲面断层片左右两侧各指标的测量结果无统计学差异，全颌曲面断层片和头颅侧位片关于上颌第三磨牙倾斜角度、上下颌萌出间隙及下颌升支长度的指标均具有强相关性（P〈0．01）。相关系数和回归方程显示，全颌曲面断层片和头颅侧位片测量值之间呈明显的线性关系，但二者不能相互替代。结论：应用全颌曲面断层片可以替代头颅侧位片评价第三磨牙萌出的影响因素。     

X线全颌曲面断层片与X线头颅侧位片相关性的研究

目的：研究X线全颌曲面断层片与头颅侧位片上对应的垂直向角度及线距是否具有相关性。方法：随机选取49名患者同期拍摄的X线全颌曲面断层片与头颅侧位片，测量每位患者两张X线片上对应的垂直向角度及线距，对测量结果进行统计分析。结果：X线全颌曲面断层片与头颅侧位片上的FH-MP角(下颌平面角)Go-FH距对Me-FH距比值呈高度线性相关；FH-PP角、FH-OP角(He平面角)呈弱相关，X线全颌曲面断层片上Go-FH对Me-FH距的比值与头颅侧位片上的Co-S距对Me-N距的比值(前后面高比)呈高度线性相关。结论：可通过X线全颌曲面断层片对垂直骨面型进行诊断。     

下颌骨牵张成骨术后1 ~ 3年稳定性的回顾性研究

目的通过头影测量牵张成骨术后下颌骨的变化,评估手术的长期稳定性并探讨影响术后复发的因素。 方法筛选2009—2018年于中山大学附属口腔医院口腔颌面外科因患有下颌骨畸形而接受下颌牵张成骨治疗的5例患者,对比不同治疗阶段[T0（下颌骨牵张成骨术前）、T1（牵张成骨治疗完成时/取出牵张器时）、T2（术后最长随访时间）]的头影测量数据,检测记录牵张成骨治疗过程中下颌骨长度（Go-Gn、Ar-Gn）及升支高度（Cr-Go）、下颌后缩程度（SNB角）的数值变化,评估牵张成骨治疗的长期稳定性。采用配对t检验的方法对头影测量数据进行统计学分析。 结果全颌曲面断层片显示,患者下颌骨长度在下颌牵张成骨手术后随访时比手术前平均增长6.09 mm（t = 2.97,P = 0.025）,下颌升支平均增长5.72 mm（t = 3.21,P = 0.018）。侧位片显示患者下颌骨长度在下颌牵张成骨手术后随访时比手术前平均增长8.17 mm（t = 5.21,P = 0.006）,下颌总长度平均增长12.58 mm（t = 4.34,P = 0.01）,下颌升支平均增长6.36 mm（t = 4.26,P = 0.01）,SNB角平均增大6.28°（t = 5.28,P = 0.006）。但是测量结果示：升支高度在手术后随访时比手术刚完成时平均降低2.25 mm（t = -3.42,P = 0.014）。 结论牵张成骨手术对下颌骨畸形患者的下颌骨体部长度和升支高度有明显的效果,并且具有良好的长期稳定性,但术后1 ~ 3年全颌曲面断层片可检测到升支高度的轻微复发现象。     

13～17岁正常He青少年下颌骨的生长发育纵向研究

目的通过对正常He青少年定期连续拍摄的系列定位头颅侧位片的X线头影测量分析,研究下颌骨生长的纵向变化特点。方法研究样本包括33名北京地区正常He青少年,其中男性11人,女性22人。对每位研究对象每年1次拍摄系列定位头颅侧位片,并进行X线头影测量分析,使用SAS6．08进行一般性统计。结果研究中发现：从13到17岁：1．关节角增加1．86&#176;,下颌角和下颌平面角减少1．0～1．5&#176;,下颌向上向前旋转,男女性别差异不显著。2．下颌长、下颌体长、升支高和颏厚及下牙槽长度的变化量均有显著或高度显著的差异,男性大于女性。3．下颌骨的生长速度不一致,以13到14岁的生长量最为明显,男性生长量约为女性的2倍;下颌长度的发育男性落后于女性约2年,16岁后无显著差异。结论本研究得到的下颌骨的纵向生长变化如生长量、生长方向等特点有助于临床医生作出合理而正确的诊治计划。     

重庆地区同一面部生长型女性青春发育高峰期颌骨头影测量的研究

目的了解同一面部生长型女性在青春发育高峰期下颌骨的生长变化趋势。方法选取符合纳入标准的青春发育高峰前、后期女性X线头颅侧位片各80张进行测量,对不同面部生长型不同时期的头影测量结果进行统计学对比分析。结果青春发育高峰前、后期①下颌升支的高度(Co-Go)、下颌体的长度(Go-Pog)有显著增加;②垂直面部生长型下颌高度的增加比水平面部生长型的增加明显;③下颌角(Ar-Go’-Me)、面轴角(Nba-PtGn)相对恒定。结论同一面部生长型不同时期下颌骨的生长存在差异。     

13～17岁正常青少年下颌骨的生长发育纵向研究

目的　通过对正常青少年定期连续拍摄的系列定位头颅侧位片的X线头影测量分析 ,研究下颌骨生长的纵向变化特点。方法　研究样本包括 33名北京地区正常青少年 ,其中男性 1 1人 ,女性 2 2人。对每位研究对象每年 1次拍摄系列定位头颅侧位片 ,并进行X线头影测量分析 ,使用SAS 6 .0 8进行一般性统计。结果　研究中发现 :从 1 3到 1 7岁 :1 .关节角增加 1 .86° ,下颌角和下颌平面角减少 1 .0～ 1 .5° ,下颌向上向前旋转 ,男女性别差异不显著。 2 .下颌长、下颌体长、升支高和颏厚及下牙槽长度的变化量均有显著或高度显著的差异 ,男性大于女性。 3.下颌骨的生长速度不一致 ,以 1 3到 1 4岁的生长量最为明显 ,男性生长量约为女性的 2倍 ;下颌长度的发育男性落后于女性约 2年 ,1 6岁后无显著差异。结论　本研究得到的下颌骨的纵向生长变化如生长量、生长方向等特点有助于临床医生作出合理而正确的诊治计划。     

自体喙突移植重建髁突对儿童颞下颌关节强直患者下颌骨生长的远期影响

目的 儿童期下颌骨髁突受损通常导致错颌畸形和面部生长不协调。本研究目的是评价自体喙突移植重建下颌骨髁突对儿童颞下颌关节强直患者面部生长发育的远期影响。方法 追踪评估2008年1月1日至2016年12月31日期间收治于四川大学华西口腔医院正颌及关节外科的10名单侧颞下颌关节强直的儿童患者,其中包括3名男性和7名女性,于5~12岁期间接受了关节间隙成形术、同侧喙突移植髁突重建术和带蒂颞筋膜瓣置入术。术后追踪3~8年,平均4.9年。术后拍摄曲面断层X线片,测定患侧下颌体长度和下颌支高度的生长量并与健侧相比较。结果 所有患者术后恢复良好,追踪结束时10名患者的最大开口度为32~41 mm,平均35.6 mm。自体喙突移植重建髁突解除强直后下颌支高度和下颌体长度均继续生长,但是依然存在生长不足的现象。与初始数据（术后）相比,患侧下颌支高度（随访结束）增加了25.3%（P<0.05）,患侧下颌体长度增加了26.1%（P<0.05）。对比患侧与健侧的下颌骨生长率,患侧下颌支高度增长量与健侧相比少47.1%（P<0.05）,患侧下颌体长度的增长量与健侧相比少27.2% （P<0.05）。结论 自体喙突移植重建下颌骨髁突治疗儿童颞下颌关节强直后,患侧下颌骨可继续生长,但依然会存在生长不足的现象。在颞下颌关节强直治疗完成后,相比于健侧,患侧的生长率是减小的。     

无牙颌下颌骨大小和形态变化的初步研究

本实验对５６例无牙颌患者（２８例牙嵴丰满者和２８例牙嵴萎缩者）的Ｘ线侧位片。应用中轴转换方法得到下颌骨中轴各线距和角度，并测量其线距和角度。结果表明：随着牙嵴吸收的增加，下颌体长度和下颌支长度增加；前牙槽突，颏突，颌内前部高度，颌骨后部高度及突长度减少。下颌休体和下颌支的连接更超于平坦；喙突和髁突更超于接近；前牙槽突向舌侧倾斜，说明牙槽骨的吸收使下颌体高度发生较大的变化。     

Measurement accuracy with a new dental panoramic radiographic technique based on tomosynthesis

Objective:To investigate measurement errors and head positioning effects on radiographs made with new dental panoramic radiograph equipment that uses tomosynthesis.Materials and Methods:Radiographic images of a simulated human head or phantom were made at standard head positions using the new dental panoramic radiograph equipment. Measurement errors were evaluated by comparing with the true values. The phantom was also radiographed at various alternative head positions. Significant differences between measurement values at standard and alternative head positions were evaluated. Magnification ratios of the dimensions at standard and alternative head positions were calculated.Results:The measurement errors were small for all dimensions. On the measurements at 4-mm displacement positions, no dimension was significantly different from the standard value, and all dimensions were within ±5% of the standard values. At 12-mm displacement positions, the magnification ratios for tooth length and mandibular ramus height were within ±5% of the standard values, but those for dental arch width, mandibular width, and mandibular body length were beyond ±5% of the standard values.Conclusions:Measurement errors on radiographs made using the new panoramic radiograph equipment were small in any direction. At 4-mm head displacement positions, no head positioning effect on the measurements was found. At 12-mm head displacement positions, the measurements for vertical dimensions were little affected by head positioning, while those for lateral and anteroposterior dimensions were strongly affected.     

Predicting vertical growth of the mandibular ramus via hand–wrist radiographs

Aim

The purpose of this study was to investigate whether growth increments of the mandibular ramus in the vertical direction can be predicted using cephalometric variables in combination with a hand?Cwrist radiograph.

Patients and methods

Our data comprised cephalograms taken at the beginning (T1) and end (T2) of orthodontic treatment, and hand?Cwrist radiographs taken at T1 of 49 adolescent patients with a Class I malocclusion. Cephalograms were scanned and analyzed with the aid of a computer. Relative growth increments (in %) of body height and different cephalometric variables during the observation period were recorded. Growth changes were compared statistically to each other and to the growth prediction assessed with the hand?Cwrist radiograph according to Greulich and Pyle (GPP). Stepwise linear regression (SPSS?) was used to statistically analyze the impact of gender, age, body height, growth prediction as assessed with a hand?Cwrist radiograph, and cephalometric variables at T1 on changes in the increase in the height of the mandibular ramus.

Results

Growth prediction assessed via hand?Cwrist radiographs at the beginning of treatment did not enable a reliable prediction of the remaining vertical growth of the mandibular ramus. Only the patient??s gender and height of the mandibular ramus at the beginning of treatment had a statistical impact on growth changes in the ramus height that occurred during the observation period.

Conclusion

Our results suggest that the vertical growth potential of the mandibular ramus cannot be predicted by analyzing hand?Cwrist radiographs or by evaluating cephalometric variables other than the initial mandibular ramus height.     

A study on a method to identify the border between mandibular corpus and ramus on lateral cephalometric radiograph.

The mandible has two major parts, the corpus and the ramus. These two parts must be considered separately because each has its own functional counterpart with the maxilla and the posterior cranial base. Since the mandible is a single bone, the border of the corpus and the ramus can not be visualized on the conventional two-dimensional lateral cephalometric radiograph. The purpose of this study is to propose a reliable method to distinguish the border between the mandibular corpus and the ramus on the lateral cephalometric radiograph. In this study, 64 dried skulls in different developmental stages were examined. Metallic markers were placed at the diverging point (point T) on both sides of the dried skulls. From the occlusal view of the mandible, point T was considered to be the lingual border of the corpus and the ramus. Then, the lateral cephalometric radiographs of the dried skulls were taken. On each lateral cephalometric radiograph, a vertical line L was drawn from point Ra (the intersection of the occlusal plane and the anterior border of the ramus) to the mandibular plane. Thus, the distance from the midpoint of point T on each side to the vertical line L was measured. As a result, over 80% of the midpoints T were found on the vertical line L. Therefore, the vertical line L from point Ra to the mandibular plane can be considered to play the role of a reasonable reference line for distinguishing between the corpus and the ramus on the lateral cephalometric radiograph.     

不同测量方法对种植术区垂直骨量的临床评价

目的：应用不同方法对种植标记物垂直向失真率的测量，对拟种植区域骨量进行正确评价。方法：在普通X线胶片上应用直接测量和间接数字化图像的计算机辅助测量法对已知长度的种植体进行测量，并与在直接数字化全景片（DR）上标记物测量的结果进行失真率对比，了解3种测量方法之间失真率的差异。结果：普通胶片应用直接测量法得到不同区域垂直向失真率大于间接数字化图像的计算机辅助测量结果，而在DR上测量得出的误差率明显小于前者。结论：应用全景片进行种植术前检查及骨量评估中，DR测量结果较普通胶片直接测量和间接数字化图像的计算机辅助测量计算出的失真率更小，数据更接近真实值，可为临床种植术前及术后评估提供可靠依据．     

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目的    探讨单侧正锁牙合患者的髁突形态特点及对称性差异，为临床诊疗提供一定的参考依据。方法    选择2007—2009年青岛大学医学院附属医院口腔正畸科收治的28例单侧正锁牙合患者为试验组，其中男13 例，女15 例，年龄14 ～39岁，平均（19.64±5.45）岁。选择同期收治的28例安氏Ⅰ类错牙合患者作为对照组，其中男10 例，女18 例，年龄14 ～38岁，平均（18.93±5.13）岁。试验组与对照组均拍摄数字全颌曲面断层片，并将其输入计算机后利用Adobe Photoshop软件测量，比较髁突形态特点。结果    （1）试验组与对照组髁突形态的不对称在性别上差异均无统计学意义（P＞0.05）。（2）试验组与对照组之间髁突上部高度（UH）的不对称指数比较差异有统计学意义（P＜0.05），升支高度（RH）以及上部高度与升支高度之和（URH）的不对称指数比较差异无统计学意义（P＞0.05）。（3）试验组和对照组每侧髁突上部高度与升支高度的比值（U／R）及髁突高度与髁突颈部宽度的比值（H／W）差异均无统计学意义（P＞0.05）。结论    单侧正锁牙合患者髁突上部高度存在不对称，提示我们单侧正锁牙合应尽早矫治。     

Panoramic radiographic findings of the mandibular growth from deciduous dentition to early permanent dentition

The outlines of mandibular rami, condyles, coronoid process, and corpus in panoramic radiographs of normal children from deciduous to early permanent dentition were traced and digitized. Nine linear and four angular measurements were measured. During the observation period, the lengths for all the linear measurements increased, however, the angles for all the angular measurements decreased. The shape of condyle and gonion significantly correlated with the growth of ramus and corpus.     

颌骨骨密度和全身骨密度的相关性研究

目的:研究骨质疏松患者与正常对照人群下颌骨相关指标的差异,探讨颌骨骨密度和全身骨密度相关性。方法:应用计算机处理软件对80例健康对照组和40例骨质疏松患者的数字曲面体层片的颌骨骨密度及相关指标测量:牙槽骨骨密度、骨高度、下颌骨下缘皮质厚度(CW)、曲面体层下颌指数(panoramic man-dibular index,PMI)、牙槽骨吸收指数(mandible resorption index,MRI)进行测量分析,并用SPSS12.0进行统计学处理。结果:骨质疏松患者组和健康对照组的CW(3.8vs4.27)、PMI(0.30vs0.33)有显著性差异(P<0.05),而骨高度(10.64vs10.56)、牙槽骨骨密度、MRI没有明显差异(P>0.05)。结论:老年性骨质疏松患者下颌骨骨形态改变明显,全身骨代谢和颌骨骨质的改变有一定相关性。     

Panoramic radiographs: determination of mandibular steepness

The aim of this study was to evaluate the potential of panoramic radiographs to measure mandibular inclination and steepness. Standardized panoramic and lateral cephalometric radiographs were taken for 95 subjects (46 females, mean age 12.4 +/- 1.2 years; 49 males, mean age 12.1 +/- 1.3 years). Mandibular inclination from panoramic radiograph was measured using gonial angle formed by the tangents of the lower border of the mandible and the distal border of the ascending ramus and the condyle. A correlation test was performed to check for similarity between the measurements. The mean values for the gonial angle were 127.3 +/- 6.2 and 125.7 +/- 6.5 degrees measured from the panoramic and cephalometric radiographs respectively. A high correlation between the measurements taken from both radiographs was found (r = 0.83, P < 0.001). Panoramic radiographs are a useful tool for the measurement of gonial angle, which is an indicator of manibular steepness and subsequently mandibular growth direction. The ability to determine growth direction from the orthopantomogram will be useful because majority of dentists request an OPG for patients during routine dental examination. This will enable the dental professional to spot vertical growth problems using a readily available tool.