前磨牙根尖片分角投照与平行投照牙齿长度的对比研究

目的探讨前磨牙区分角投照根尖片和平行投照根尖片在评价牙齿长度方面的差异.方法选取64颗因正畸需要拔除的牙齿,拔除前同期拍摄分角投照和平行投照根尖片.将两种根尖片的影像长度和牙齿实际长度之间分别进行配对t检验.结果在前磨牙区,分角投照、平行投照根尖片影像长度和牙齿实际长度之间无显著性差异.结论前磨牙区的分角投照根尖片和平行投照根尖片均能精确反映牙齿的实际长度.     

根尖片平行投照技术在牙周病诊断中的应用简介

牙周病是口腔科最为常见的疾病之一,X线片对于牙周病诊断,牙周病病程进展及治疗效果的观察等均具有重要意义。由于曲面体层摄影X线片的清晰度、锐利度较差,牙齿牙槽突影象失真较大,难以对牙槽突的情况进行准确观察,因而在临床上仍然广泛应用根尖片分角技术检查方法。国外目前已广泛应用根尖片平行投照技术,而国内目前尚未推广应用。本文将对平行投照技术的投照方法,投照要点及优缺点做重点叙述。平行投照技术是由Mccormick1902年首先描述,摄影原理是胶片位置与被照牙齿的长轴平行,X线中心线垂直于被照牙的长轴和胶片中心(图1)。     

平行投照根尖片估测根管工作长度准确性的研究

目的平行投照根尖片估测单根管牙根管工作长度的准确性。方法对92颗拟行根管治疗的单根管牙术前拍摄平行投照根尖片，测量其牙根长度，测量值减去0．5mm即为估计工作长度，再与实际根管工作长度比较，研究其在临床可接受范围内的准确性，并用秩和检验检测两者有无差异。结果平行投照根尖片估测单根管牙根管工作长度的准确率为89．13％，与实际工作长度差异无统计学意义。结论单根管牙在根管治疗术前拍摄平行投照根尖片估测工作长度的准确率高。     

关于创伤的计算机辅助光研究

目的为了定量研究创伤，确定可以协助临床诊断咬合病人的客观指标及鉴别正常与创伤的依据。方法利用计算机图像处理技术，自行编制计算机软件程序及硬件系统用于光分析，可全面提取，分析咬合信息。结果可识别每个牙及全牙列的咬合接触区数目、面积、接触应力和接触力等定量指标，能准确、迅速地评价咬合的性质与状态。结论创伤有以下特点。①与正常比较，创伤有明显的异常接触区，该区的接触面积或接触力明显增大。②从牙列远—近中向分析，会有某项观察指标梯度颠倒的表现，违反由磨牙区向切牙区逐渐递减分布的规律。③牙弓两侧存在有严重的不协调、不对称现象。     

头颅激光定位投照装置的研制及应用

明确诊断各种牙颌畸形,设计最佳矫治方案,Ｘ线头影测量是主要参考依据之一。我们自行研制了简易的头位固定器,即用胸片架改制成使用方便的自然头位专用盒架,利用综合医院的普通Ｘ线机,在球管上方正中放置激光校准发生器,为使球管中心对准头定位器作者单位：２２１０...     

平行和分角线投照数字根尖片测量种植体的准确性研究

目的通过比较平行和分角线投照数字根尖片(digital periapical radiographs,DPR)测量种植体长度和直径的准确性,为DPR评价种植体周围骨组织水平提供参考。方法160名患者210颗种植体,按随机数字表法分为平行投照组(80例患者,98颗种植体)和分角线投照组(80例患者,112颗种植体),术后即刻拍摄DPR。利用软件SOPRO Imaging 2.20盲法测量DPR上种植体的直径和长度,然后与种植体实际值比较,利用SPSS软件进行两元方差分析和LSD多重比较,评价两种投照DPR测量的准确性。结果平行投照DPR测量直径和长度与种植体实际值的差值分别为(0.14±0.10)mm、(0.20±0.15)mm,水平和垂直放大倍率分别为1.58%、2.13%;分角线投照DPR测量直径和长度与种植体实际值的差值分别为(0.37±0.22)mm、(1.04±0.47)mm,水平和垂直放大倍率分别为3.90%、10.65%。平行投照DPR测量种植体长度和直径的准确性均优于分角线投照DPR(P<0.05)。结论平行投照DPR能更准确地测量种植体的直径和长度,提示利用平行投照DPR能更准确地评价种植体周围的骨组织水平。     

根尖片定位摄片影响因素分析

为对影响咬合板定位摄片系统稳定性的因素提出改进意见，作者研究了影响小型猪定位牙根尖片投照稳定性的因素。结果表明：影响牙片定位投照重复性的主要因素有咬合板印模深度、连接杆的强度等。为改善牙片数字减影的效果，定位咬合板印模深度应大于２．５ｍｍ，以达到牙龈缘（４ｍｍ±）为最佳。投照时应防止咬合板颊舌向轻微旋转翘动。连接杆的强度应足够大，以免连接杆变形变曲。当连接杆强度增大后，咬合板印模深度的要求可以适当放宽，以便扩大适用范围并提高减影质量。     

口腔医学生根尖片投照失败原因分析

根尖片是口腔科医师诊断牙患的重要手段，是口腔临床中应用最多的一种X线片。根尖片投照技术是口腔医学专业学生必须掌握的基本技能之一。根尖片的密度、清晰度、对比度和失真度的好坏直接影响到疾病的诊断与治疗。笔者把近三个月2002级学生在我科实习所拍摄的3378张牙片进行分析，研究根尖片投照失误的类型及其与牙位的关系，以便发现教学过程中存在的问题并予以改进，为今后实习学生减少失误，提高根尖片的质量，降低废片率、减少患者不必要的X线照射提供帮助。     

X线投照角度对根尖片诊断牙根吸收影响的研究

目前，根尖片和曲面断层片是诊断牙根吸收的常用方法。与曲面断层片相比，根尖片的投照技术能够保证获得更加准确的影像，更加有效地诊断正畸牙根吸收。但是在拍摄根尖片时，有许多因素可能造成影像的失真。这些因素包括：X线的投照角度、牙齿-胶片位置关系、焦点-胶片距离、牙齿-胶片距离等。其中，X线的投照角度最难控制。     

平行和偏移投照根尖片在确诊上颌第一磨牙近中颊根第二根管中的作用

目的：探讨X线片检查在确诊上颌第一磨牙近中颊根第二根管（MB2）中的作用。方法：选取临床上需要进行上颌第一磨牙牙髓治疗 患者59例作为实验对象。每个患牙均需拍摄术前X线正位投照片、X线偏移投照片和诊断丝正位、偏移投照片。患牙经根管治疗术后，计算MB2的发现率。比较4种X线投照方法与MB2发生率的相关关系。结果：59例59个患牙中，存在MB2的患牙为24个，占40.7%。X线正位投照片发现根管偏移的占49.2％，X线偏移投照片发现根管偏移的占52.5%，诊断丝正位投照片发现根管偏移的占44.1%，诊断丝偏移投照片发现根管偏移的占55.9%。统计学分析显示：X线正位投照片和诊断丝正位投照片中根管偏移比率与MB2发生率无显著性差异（P＞0.05）；应用偏移投照，发现二者之间存在显著性差异（P＜0.05）。结论：根据不同角度X线片和诊断丝照相，分析根管影像偏移程度，有助于寻找和确定MB2根管的存在。     

Deleterious effect of chronic continuous hypoxia on oral health

ObjectiveTo evaluate the effect of chronic continuous hypoxia (CCH) in alveolar bone and its correlation with the inflammatory markers which play a key role in the development of periodontitis.Material and methodsWistar rats were exposed to CCH (600 mbar, 3 months). Macroscopic and histological analyses of alveolar bone were performed, together with measurement of oxidative stress and inflammatory parameters in gums and submandibular glands (SMG).ResultsHCC induced cortical alveolar bone loss, decreased interradicular bone volume and increased the periodontal ligament height compared to control rats (p < 0.05). CCH enhanced iNOS activity in gums (from 2735,04 ± 662,96 nmol/min/mg proteins to 4289,58 ± 915,63 p < 0.05) and in SMG (from 56,71 ± 12,05 nmol/min/mg proteins to 90,15 ± 21,78 p < 0.05). PGE₂ did not change in gums or in SMG by means of CCH, while TNFα decreased in gums (p < 0.05). Regarding oxidative stress, thiobarbituric acid reactive species concentration in CCH animals was higher both in gums as in SMG, and catalase activity was decreased in SMG.ConclusionHigher iNOS activity both in gums and SMG under CCH could be associated with the alveolar bone loss observed. The increase in oxidative stress occurring in SMG and gums, together with a lower antioxidant capacity might indicate a deleterious effect of HX in oral health.     

淫羊藿苷口服给药对骨质疏松牙周炎小鼠牙槽骨吸收的影响

目的:研究口服淫羊藿苷（ICA）对骨质疏松小鼠牙周炎引起的牙槽骨吸收的抑制作用。方法:3月龄、雌性、C57BL/6J小鼠随机分为3组,即正常组（SHAM组）、卵巢切除+口腔涂布牙龈卟啉单胞菌（Pg）+淫羊藿苷组（OVX+Pg+ICA）、卵巢切除+Pg口腔涂布组（OVX+Pg）。小鼠适应性喂养1周,第2周进行双侧卵巢切除术,诱导小鼠骨质疏松形成。从第4周开始,对小鼠牙周涂布Pg,1次/d,连续1周。第12周收集左侧下颌骨进行固定切片及染色,分析各组之间牙槽骨吸收高度的差异。收集右侧下颌骨进行亚甲蓝染色,分析各组间牙槽骨吸收面积的差异;收集双侧上颌骨牙周组织蛋白,分析成骨相关蛋白的表达差异。采用SPSS16.0软件包对数据进行统计学分析。结果:小鼠股骨及牙周组织切片染色显示,成功建立了小鼠骨质疏松牙周炎模型。对牙槽骨吸收距离和面积的测量分析显示,相比于OVX+Pg组,口服淫羊藿苷可显著减少釉-牙骨质界-牙槽嵴顶（CEJ-ABC）的距离及颊舌侧牙槽骨吸收面积（P<0.05）;Western免疫印迹显示,相比于OVX+Pg组,OVX+Pg+ICA组中Runx2、OSX、OCN及OPN蛋白表达水平显著升高（P<0.05）。结论:口服淫羊藿苷在预防小鼠骨质疏松发生的同时,可有效减少牙周炎引起的牙槽骨吸收。     

Techniques for assessing alveolar bone mass changes in periodontal disease with emphasis on 125I absorptiometry

Abstract. No practical methods are presently available for measurement of alveolar bone activity at one instant of time. However, roentgenological methods making measurements at 2 different times can be used to assess alveolar bone activity. The most sensitive, specific and accurate method for this purpose presently in use is ¹²⁵I absorptiometry. This method has the further advantage of giving the patient minimal radiation exposure. New methodology is under development which obviates the need for fixed geometry and could provide a 3-dimensional image of alveolar bone.     

雌激素缺乏对大鼠牙槽骨吸收影响的实验研究

目的观察雌激素缺乏对大鼠牙槽骨吸收的影响。方法34只雌性SD大鼠随机分为4组。第1组假手术(n=8),第2组卵巢切除(n=9),第3组卵巢切除加牙周结扎(n=9),第4组卵巢切除、牙周结扎加雌激素治疗(n=8)。适应性喂养7天后行假手术或双侧卵巢切除术。第4组于术后第二天起皮下注射苯甲酸雌二醇．20μg／kg体重／次,三天一次。第3、4两组于卵巢切除术后28天,结扎丝结扎上颌第一磨牙诱导牙周炎。第63天处死全部大鼠。常规取材。观察牙用组织组织学改变。测量牙用骨丧失值(PBL)。比较牙用骨支持率(PBS)。检测血清碱性磷酸酶(ALP)。结果采用成组f检验,第1、2两组的PBL分别为0．398±O．147mm,0．663±0．132哪。PBS分别为O．588±O．058。0．440±0．197,组间差异均有统计学意义(P<0．05);第2、3两组的PBL、PBS组间差异均有统计学意义(P<0．05)。第3组的PBL为0．875±0．197mm,PBS为0．336±O．087;第3、4两组的PBL、PBS组间差别没有统计学意义(P>0．05),第4组的PBL为O．823±0．119mm,PBS为0．360±0．950。结论雌激素缺乏促进牙槽骨吸收,茵斑刺激加剧骨质疏松大鼠牙槽骨的吸收,雌激素替代治疗不能预防骨质疏松大鼠因茵斑刺激引发的牙槽骨吸收。     

牙槽骨吸收与吸烟状况的研究

目的: 评价不同程度牙槽骨吸收的牙数与每日吸烟量和血浆中cotinine水平的关系。方法: 120名未治疗的慢性牙周炎患者,男 48,女 72,平均年龄 42. 3岁。根据自述的吸烟状况分组。116人检测了血浆cotin ine水平。根据骨吸收达根长的冠 1 /3、中 1 /3和根 1 /3, 牙槽骨吸收分为轻、中、重度骨吸收。结果:cotinine水平与自述的吸烟状况呈正相关(P<0. 001)。重度吸烟组较非吸烟组,中度骨吸收的牙齿数明显增多;而非吸烟组,无骨吸收的牙齿多(P值均<0. 001)。结论:吸烟>10支 /d是牙槽骨吸收牙数增加的重要危险因素。     

Development of an opto-electronic positioning device for serial direct digital images of oral structures

The aim of this study was to develop and test in vitro an opto-electronic positioning device for serial direct digital images of oral structures, i.e. to associate direct digital imaging with the principles of computer-aided surgery. This system registered positions of infrared light emitting diodes (LED) on carriers, establishing local coordinate systems. With LED markers attached on the sensor holder, the X-ray tube and a fix reference, the opto-electronic camera (Optotrak) registered the geometric source/detector relation. A specially designed tracking and guidance software was developed which enabled the operator to reposition the X-ray source. A graphical user interface guided the operator in aligning 2 circles to the reference axis, one indicating the origin of the beam, the other its tip. In addition, depth control was provided. An in vitro calibration was performed. A sensor holder/bite block carried the Sens-A-Ray sensor with a hair-cross. In front of the object a second hair-cross was fixed. A steel ball fixed to the center of the X-ray cone allowed to verify the alignment. The mean angulation error in the vertical plane was 0.06 degrees and 0.04 degrees in the horizontal one. Translation mean errors were small and ranged between -0.02 mm and 0.37 mm. The translation in the Z axis is negligible. This resulted in pairs of images suitable for digital subtraction. Although still in an experimental state, the results showed that opto-electronic navigation was useful to standardize projection geometry without any mechanical link and to achieve digital subtraction images based on direct digital imaging.     

侵袭性牙周炎牙槽骨吸收状况及相关因素分析

目的 评价未经治疗的侵袭性牙周炎(aggressive periodontitis,AgP)患者牙槽骨吸收状况并分析与牙槽骨吸收状况有关的因素,以期为临床提供参考.方法 对108例未经治疗的AgP患者[男45例,女63例;年龄≤25岁者34例(A组),＞25岁者74例(B组)]进行吸烟状况和教育背景的问卷调查,并测量全口牙邻面位点探诊深度(probing depth,PD,浅袋:PD=3、4 mm,中袋:PD=5、6 mm,深袋:PD≥7 mm);根据全口X线根尖片评价邻面牙槽骨吸收状况(轻、中、重度骨吸收).结果 实际共测量了2841颗牙.浅袋与轻度骨吸收(r=0.518,P=0.000)、深袋与重度骨吸收(r=0.366,P=0.000)均呈正相关;AgP患者男性轻、中、重度骨吸收牙数(分别为7.1±6.2、12.5±4.7、5.1±0.6)与女性(分别为8.7±6.3、12.9±4.8、4.2±0.5)差异无统计学意义(P值分别为0.707、0.671和0.413);B组中、重度骨吸收牙数(分别为13.6±4.2、5.2±3.7)显著多于A组(分别为11.0±5.5、3.6±3.5),P＜0.01;受过高等教育和未受高等教育者轻、中、重度骨吸收牙数差异无统计学意义(P值为0.314、0.862和0.407);吸烟是重度骨吸收AgP患者的危险因素之一(OR=1.961).结论 AgP患者PD与牙槽骨吸收程度相关;年龄和吸烟是影响AgP患者牙槽骨吸收的重要因素.     

Cone positioning device for oral radiation therapy

This article describes the fabrication and modification of a peroral cone-positioning device. The modification provides added cone stability and prevents tongue intrusion into the radiation field. This device provides a repeatable accurate cone/lesion relationship and the fabrication technique is simplified, accurate, and minimizes patient discomfort.     

Effects of glucocorticoid-induced osteoporosis on bone tissue of rats with experimental periodontitis

ObjectiveTo evaluate the effects of osteoporosis induced by glucocorticoid (GIOP) on bone tissue of rats with experimental periodontitis (EP).Design48 male Wistar rats divided into groups: Naïve, EP, GIOP and GIOP + EP. Rats of GIOP and GIOP + EP groups received 7 mg/kg of dexamethasone intramuscularly once a week for 5 weeks. Following, EP and GIOP + EP groups were subjected to ligature-induced periodontitis. Naïve group experienced no manipulation. After 11 days, the animals were euthanized and left maxillae collected for macroscopic, radiographic, micro-tomographic and microscopic analysis of alveolar bone loss (ABL). Blood samples were collected for determination of bone-specific alkaline phosphatase (BALP) levels and the right femurs were removed for radiographic and biomechanical analysis.ResultsEP caused ABL and reduced BALP levels (p < 0,05), but it did not change the architecture or biomechanics of femur, compared to Naïve. GIOP did not cause ABL, but it significantly decreased alveolar bone mineral density (ABMD), bone percentage and trabecular thickness (Tb.Th) and increased alveolar bone porosity (p < 0.05) and significantly reduced BALP serum levels, as well as radiographic density and Young’s module of femur, compared to Naïve. There was a greater ABL in group GIOP + EP when compared to EP (p < 0.05). GIOP + EP caused a greater decrease on ABMD, Tb.Th, bone percentage and increased bone porosity (p < 0.05) and also presented a significant reduction in BALP levels (p < 0.05), in radiographic density and in Young’s module of femur compared to EP (p < 0.05).ConclusionsGIOP can potentiate the destructive effects of EP on alveolar bone and alter the systemic bone loss, by promoting bone resorption and reducing osteoblast activity.     

颞下颌关节及下颌骨的磁共振三维重建

探讨对颞下颌关节进行ＭＲ影像三维重建的可行性,方法在对颞下颌关节颌骨进行磁共振扫描的基础上,运用计算机工作站的三维重建功能,对磁共振断层影像进行三维重建。结果重建后的髁突,关节盘、关节窝及下颌骨均具有较好的形态进行不同角度的旋转,可清楚地观察到关节窝、关节和髁突的位置关系。