乙二胺四乙酸和枸橼酸对细小根管制备的实验研究

目的研究乙二胺四乙酸（ＥＤＴＡ）和枸橼酸对细小根管的作用，为临床应用提供实验依据。方法甲乙两组分别对１４个离体牙细小根管用１７％ＥＤＴＡ和５０％枸橼酸处理３天。结果用１７％ＥＤＴＡ溶液经过３天处理的１４个细小根管全部有效，总有效率１００％，且扩大深入达４ｍｍ以上的有１１个根管，有９个根管达到工作长度。用５０％枸橼酸溶液经过３天处理的１４个细小根管中有效１１个，无效３个，总有效率７８．５７％，有８个根管扩大深入达４ｍｍ以上，并达到工作长度。甲乙两组的扩大深入程度，经统计学处理有显著性差异（Ｐ＜０．０１）。结论ＥＤＴＡ是化学制备细小根管的首选药物     

口腔矫治器治疗阻塞性睡眠呼吸暂停综合征：附10例报告

用夜间多导睡眠图监测结合Ｘ线头影测量法，分析了口腔矫治器对１０例阻塞性睡眠呼吸暂停综合征患者气道、睡眠结构及呼吸功能的影响。结果显示，戴用矫治器后下颌在水平向和垂直向的位移平均分别为１．７３ｍｍ和９．３０ｍｍ，上后气道间隙平均增加２．８０ｍｍ（Ｐ＜０．０１），中气道间隙平均增加６．７５ｍｍ（Ｐ＝０．０１），下气道间隙变化的差异无显著性（Ｐ＞０．０５）。１０名患者的呼吸暂停指数平均下降１５．９８次／小时（Ｐ＜０．０１），有９名患者总呼吸紊乱指数平均下降３２．８１次／小时（Ｐ＜０．０１），另一例无低通气记录。最低ＳａＯ２平均从７３．８７％上升到８５．５０％（Ｐ＜０．０１）。上气道阻塞频率的降低，可归因于矫治器对口咽部结构的影响。作者认为，口腔矫治器是治疗该病的一种有效疗法。     

不同医生两次读X线直视摄影术牙片结果的一致性研究

目的：研究不同医生两次读Ｘ线直视摄影术（ＲＶＧ）牙片结果的一致性。方法：１００张ＲＶＧ牙片经３位医生的２次盲法读片，以尖周是否有破坏为标准进行判断，用卡帕值来分析结果。结果：３位医生两两比较的卡帕值分别为０．４９、０．５７和０．５１；每位医生间隔２周的２次读片结果卡帕值分别为０．６３、０．６５和０．５８，均属中度或高度一致。结论：ＲＶＧ牙片应充分利用但不能依赖，要参考多方面的信息，才能对尖周组织是否有破坏作出正确的判断     

前方牵引治疗乳牙期骨性反合的临床探讨

本文对１３例乳牙期重度骨性反（反覆盖４－９ｍｍ）患者应用前方牵引矫正器早期治疗进行探讨。观察结果疗效十分显著。头影测量值的对比显示出骨组织变化，ＳＮＡ角平均增加２．７，有显著性差异（Ｐ＜０．０５）。ＳＮＢ角无明显变化。ＡＮＢ角及颌凸角向正值转化，有高度显著性差异（Ｐ＜０．０１）。硬组织的改变也带来软组织显著变化，使Ⅲ类错患者的面型得到较大的改善     

光固化粘结剂治疗牙本质敏感症的初探

采用单盲自身配对对照法，用光固化粘结剂和局部涂布氟化钠治疗牙颈部敏感症，平均疗效分别是７８．５％，６４．６％，经统计学处理ｐ＜０．０１，有高度显著性差别。故认为用光固化粘结剂治疗牙颈部牙本质敏感症优于氟化钠甘油糊剂脱敏法。实验组３月、６月、９月疗效分别为７４．２％、６１．３％、５８．７％，经统计学处理ｐ＞０．０５，表明其远期疗效较佳。     

人头发自由基检测在口腔颌面部恶性肿瘤诊断中的意义

作者应用电子自旋共振技术（ＥＳＲ）分别对正常人、口腔颌面部良恶性肿瘤、口腔粘膜病患者共３２４例的头发进行自由基测定，并与病理诊断相对照。结果表明，它们的阳性率分别为５．９％，６．１％，８４．５２％及９．１％。其中恶性肿瘤与正常人及良性肿瘤相比较，差别均较显著（Ｐ＜０．０１）。部分恶性肿瘤患者经治疗后，ＥＳＲ饱和功率点后移，上升到临界水准以上（＞１０．０ｍＷ），ＥＳＲ转阴。表明用ＥＳＲ早期诊断恶性肿瘤、追踪疗效具有一定临床价值。作者还结合检测资料对ＥＳＲ在监测肿瘤复发、监视白斑癌变等方面的意义进行了讨论。     

口腔粘膜扁平苔藓患者丙型肝炎病毒感染的初步研究

目的：了解ＯＬＰ患者ＨＣＶ感染情况,探讨ＨＣＶ感染与ＯＬＰ之间的关系。方法：用全自动生化检测仪,酶联免疫测定及ＰＣＲ法分别测定４１名ＯＬＰ患者和３８名对照者外周血ＳＧＰＴ、ＳＧＯＴ、抗－ＨＣＶ和ＨＣＶ－ＲＮＡ。结果：４１名ＯＬＰ患者中,１５人（３６．６％）有肝酶异常升高、１２人（２９．３％）抗－ＨＣＶ阳性,１０人（２４．４％）ＨＣＶ－ＲＮＡ阳性;而３８名对照组中,６人（１５．８％）有肝酶异常升高,３人（７．９％）抗－ＨＣＶ阳性,３人（７．９％）ＨＣＶ－ＲＮＡ阳性,ＯＬＰ组的上述三项指标均较对照组为高（Ｐ＜０．０５、Ｐ＜０．０１、Ｐ＜０．０５）,两组存在明显的差异。结论：国人ＯＬＰ患者存在较高的ＨＣＶ感染率,表明有相当部份的ＯＬＰ患者体内有ＨＣＶ存在与复制,ＯＬＰ的发病可能与此有一定的关系。     

小剂量雷公藤多甙治疗RAU对血清SOD、MDA、微量元素改变的影响

选择４０例ＲＡＵ患者与５０例正常对照，应用小剂量雷公藤多甙、锌、铁制剂、丹参治疗，探讨治疗前后患者血清ＳＯＤ、ＭＤＡ及血清元素的改变。结果显示ＳＯＤ、ＭＤＡ的改变，实验组与对照组有显著性差异（Ｐ〈０．０１），治疗前、后对比又有显著性差异（Ｐ〈０．０１），而血清Ｚｕ、Ｃｕ／Ｚｎ、Ｆｅ、Ｍｎ治疗前后有明显差异（Ｐ〈０．０１），并与ＳＯＤ、ＭＤＡ的治疗前、后改变有明显相关性（Ｐ〈０．０１）。     

正常青少年下颌切点边缘运动轨迹的定量分析

本文采用ＳＧＧ下颌运动轨迹描记仪来描记２０名正常青少年下颌切点边缘运动轨迹，并进行测量分析，结果表明：（１）正常青少年下颌切点边缘运动范围为前伸８．６４±１．８９ｍｍ、开口向后９，７５±２．８９ｍｍ、开口向下３５．７９±５．５７ｍｍ、向左８．７４±１．９２ｍｍ、向右８．７３±１．７６ｍｍ，男女间运动范围无明显差异（ｐ＞０．０５）。（２）９０％的正常青少年正中位、正中关系位是２个位置，正中关系位位于正中位的后下方，即位于后方０．８５±０．４２ｍｍ、下方０．６１±０．４６ｍｍ处，男女间无明显差异（ｐ＞０．０５）。     

口腔扁平苔藓病损区角朊细胞表达HLA－DR抗原的意义

为进一步探讨口腔扁平苔藓（ｏｒａｌｌｉｃｈｅｎｐｌａｎｕｓ，ＯＬＰ）的发病机制，作者用免疫组织化学ＰＡＰ法检测了ＯＬＰ病损区角朊细胞（ｋｅｒａｔｉｎｏｃｙｔｅ，ＫＣ）异常表达人白细胞分化抗原ＤＲ区（ｈｕｍａｎｌｅｕｃｏｃｙｔｅａｎｔｉｇｅｎ－ＤＲ，ＨＬＡ－ＤＲ）抗原的情况。结果显示，所有标本的粘膜上皮中均有ＨＬＡ－ＤＲ阳性ＫＣ，其数量和表达程度与ＯＬＰ的病程及类型有关，不同组间差异有高度显著性（Ｐ＜０．０１）。作者认为，ＯＬＰ病损区ＫＣ异常表达ＨＬＡ－ＤＲ抗原对Ｔ淋巴细胞在局部的聚集、炎性病灶的形成是至关重要的。     

Clinical validation of a new subtraction radiography technique for periodontal bone loss detection

BACKGROUND: Diagnostic subtraction radiography (DSR) is a new digital radiographic image subtraction method designed to enhance detection of crestal or periapical bone density changes and to help evaluate caries progression in teeth. In this clinical study, the performance of the DSR method was evaluated for its ability to detect periodontal bone loss and was compared with that of conventional evaluation of radiographs and the standardized cephalostat-guided image acquisition and subtraction technique (LRA) which served as the "gold standard." METHODS: In each of 25 subjects with alveolar crestal bone loss created by periodontal surgery, one set of DSR radiographs and one set of LRA radiographs were obtained before and after the surgery. Subtraction images were then generated by both the proprietary DSR and the LRA techniques. Four viewers evaluated the paired film sets and both subtraction image sets using a 5 point confidence scale to determine the presence or absence of crestal bone loss. Receiver operating characteristics (ROC) statistical procedures were applied to analyze the diagnostic accuracy and statistical differences between the three imaging modalities. RESULTS: The DSR subtraction viewing generated an ROC area of 0.882. For 2 of the viewers this represented a statistically significant gain (P <0.05) over the conventional viewing of the radiographs which had an average ROC area of 0.730. In comparison, the LRA method achieved an area of 0.954. The differences between the LRA and the DSR subtraction methods were not statistically significant, but the statistical power for claiming equality was low ranging from 0.2 to 0.6. CONCLUSIONS: The use of the DSR technique in clinical radiographic image acquisition and subsequent subtraction analysis clearly enhanced the accuracy of alveolar crestal bone loss detection when compared to conventional film viewing. Because this methodology is less resource demanding than LRA and the film exposure techniques and computer-based image analysis skills may be acquired with only a few hours of training, the DSR has potential in clinical practice.     

Efficacy of quantitative digital subtraction radiography using radiographs exposed in a multicenter trial

Digital subtraction radiography (DSR) has been shown to be a sensitive and specific method for the detection of small bony changes in periodontitis. The purpose of this study was to perform a multicenter validation of the DSR in human subjects. Seventeen subjects were enrolled at 3 centers. Feather-edged hydroxyapatite chips (approximately 1,7 and 10 mg) were used to simulate osseous lesions. Bilateral radiographs were taken with and without chips. Geometry was standardized using a cephalostat and the order of radiographs was determined using a randomization plan. Radiographs were subtracted, lesions isolated, and quantified at a single center without knowledge of the randomization code or location of the chips used in each subject. The overall sensitivity and specificity in detecting 1 mg changes was 87.8% and 100%, respectively. Sensitivity and specificity in detecting 7 mg and 10 mg chips was 100%. A strong linear relationship between actual lesion mass and calculated mass was observed (R²=0.94, slope=0.98, p<0.0001). No significant differences were observed by center. These data indicate that the DSR is a valid technique for the assessment of alveolar bone changes in multicenter trials.     

Detectability of artificial marginal bone lesions as a function of lesion depth

Subtraction of serially obtained standardized radiographs of the marginal periodontal bone offers possibilities for an increased detectability of small bony changes compared to conventional radiography. In this study, the depth of artificially induced bone lesions in the alveolar crest was assessed by means of 125I absorptiometry. The results served as reference values when a series of radiographs containing lesions of various depths was interpreted by 10 examiners. Both conventional radiographs and subtraction images made from the conventional radiographs after digitization were interpreted. The ROC-curve technique was used to evaluate the two techniques. A close to perfect accuracy was found at a lesion depth corresponding to 0.49 mm of compact bone using the subtraction technique. A similar degree of accuracy was not reached for the conventional technique until the lesions were approximately 3 times deeper.     

A pilot study of treatment of periodontal-endodontic lesions

OBJECTIVE: A pilot study to evaluate a standardised treatment protocol for combined periodontal-endodontic lesions (involving staged endodontic and periodontal treatment). PARTICIPANTS: Nine patients with a diagnosis of a combined periodontal-endodontic lesion. METHODS: At baseline, root canal treatment (RCT) was performed by a standard protocol, and simple scaling/oral hygiene instruction provided. After one month, a standardised episode of non-surgical periodontal treatment was undertaken to address residual pocketing. Clinical measurements, including probing depths, attachment levels and bleeding on probing were recorded at baseline, month one and month three. Long-cone periapical radiographs taken using standardised projection geometry at baseline and month three were analysed for bone changes using digital subtraction radiography (DSR). RESULTS: During the study, one patient's affected tooth was extracted. From baseline to month three, there were statistically significant mean probing depth reductions (delta= 0.95mm, 95% CI= 0.20mm, 1.70mm; p= 0.02), mean attachment gains (delta= 1.13mm, 95% CI= 0.29mm, 1.96mm; p= 0.02) and reduction in mean bleeding on probing (delta= 29%, 95% CI= 10%, 49%; p= 0.01). DSR analysis revealed that between month 0 and month three, four teeth demonstrated bone gain, two teeth exhibited bone loss and two teeth showed no change. The mean bone change was in favour of bone gain but failed to achieve statistical significance (p>0.05). CONCLUSIONS: Within the limitations of this pilot study, treatment of periodontal-endodontic lesions by performing RCT prior to periodontal treatment was effective, resulting in improvements in clinical parameters together with alveolar bone gains in a majority of teeth.     

Contrast enhancement as an aid to interpretation in digital subtraction radiography

An initial study was performed to demonstrate the feasibility of pseudocolor contrast enhancement technique in digital subtraction radiography (DSR). DSR is an electronic image processing technique that has been shown to be of greater diagnostic value in the detection of small periodontal bone lesions than conventional radiography. Pseudocolor enhancement involves selectively assigning a unique color to each shade of gray present in a black-and-white subtracted image. Two image enhancement techniques were developed and tested in a phantom system consisting of extracted teeth set in blocks of plaster mixed with sawdust to simulate trabecular bone. It was found that experimentally induced periodontal lesions were more readily detected by the average clinician in both types of enhanced subtraction images than unenhanced subtractions. Furthermore, both enhancement techniques were of significantly greater diagnostic value for lesions smaller than 1.0 mm (p less than 0.001). The technique that colored an isolated area of interest was significantly more diagnostic at all depths tested (p less than 0.001 at 0.5 and 1.0 mm, and p less than 0.05 at 0.5 mm). Contrast enhancement may be a significant aid to the average clinician for the interpretation of DSR and the detection of small periodontal defects.     

The detection of in vitro produced periodontal bone lesions by conventional radiography and photographic subtraction radiography using observers and quantitative digital subtraction radiography

Changes in the periodontium produced by removal of bone cylinders at one interdental site of a dry human mandible, were recorded radiographically. These artificial lesions had diameters of 0.3 mm increasing to 1.4 mm in steps of 0.1 mm. Radiographs were obtained using 3 different X-ray tube potentials and 3 different amounts of radiation. These 9 exposure variables resulted in 9 series of radiographs from the artificial lesions. Observers were asked to determine the presence or absence of these periodontal bone lesions on conventional radiographs and on photographically subtracted images. The images were also evaluated by a quantitative digital subtraction technique. This study showed that the smallest periodontal bone changes were detected with the quantitative digital subtraction technique compared to the other methods using observers. On photographically subtracted images, smaller bone changes were detected by the observers than on conventional radiographs. Only the detection threshold of the quantitative digital subtraction technique was influenced by the 2 exposure factors: kVp and mAs.     

Influence of variations in projection geometry on the detectability of periodontal bone lesions

The influence of differences in imaging geometry on the detection of small periodontal bone lesions was studied when using a digital subtraction technique. The results were compared with those from conventional radiographs. Reference radiographs were obtained on human mandibular jaws before small lesions were made in the marginal alveolar bone. Subsequent radiographs were taken with the same imaging projection as well as with changes of the angulation in either vertical, or horizontal direction, or both. 10 dentists served as observers, who compared the conventional radiographs taken before and after the lesions were made, and registered the presence or absence of lesions using a diagnostic rating scale. The conventional radiographs were digitized, and subtraction images made. These images were interpreted by the same observers. For each observer, image modality and projection, the resulting rates of true positive and false positive diagnoses were plotted on a graph. The area under the curve, obtained by connecting the paired values of true positive and false positive results associated with the different diagnostic ratings, was used as a measure of diagnostic accuracy. Statistically significant differences could be demonstrated between the results obtained from the subtraction images, whether produced from identical or non-identical pairs of conventional radiographs, and the results from the conventional radiographs obtained under ideal conditions.     

Assessment of alveolar bone loss with high resolution computed tomography

In this in vitro study we compared high resolution computed tomography (HR-CT) with dental radiographs regarding the interpretation of horizontal and vertical alveolar bone loss. After removal of the soft tissue and metallic restorations of 20 dentate upper and lower jaw segments 40 infra-alveolar bony defects of different dimensions were experimentally produced. The specimens were examined radiographically with standardized dental radiographs and 1.0 mm thick contiguous axial CT-scans. On the specimens, radiographs and CT-scans the bone loss was measured between the cemento-enamel junction and the adjacent alveolar bone level of 472 mesial and distal tooth surfaces; the identification, classification and vertical depth of the infra-alveolar bony defects were also compared. An average underestimation of 0.6 mm of horizontal alveolar bone loss in the dental radiographs and an overestimation of 0.2 mm in CT-scanning was shown. No significant differences between the imaging accuracy of horizontal alveolar bone loss between dental radiographs and CT-scanning could be evaluated. In the dental radiographs 24 (60%) of the infra-alveolar bony defects could be identified and the vertical depth was underestimated by a mean of 2.2 mm. In comparison, all 40 (100%) infra-alveolar defects could be identified in the CT-scans and the vertical depth was underestimated by an average of 0.2 mm. The HR-CT-technique offers a three-dimensional interpretation of the alveolar morpholoy without overlying structures. This permits a high identification rate and classification of infra-alveolar bone loss according to the number of surrounding bone walls into one-, two or three-walled bony pockets.     

Digital subtraction radiography for diagnosis of periodontal bone lesions with simulated high-speed systems

Standardized radiographs were obtained of the molar and premolar areas of dry human mandibles before and after small lesions were induced in the alveolar bone crest. The radiographs were digitized, and various amounts of random noise were added to simulate images produced by more efficient, low-radiation-dose systems. Subtraction images were produced from these noise-degraded radiographs. The diagnostic performance of human observers from these images was then compared with that obtained from both subtraction images made from nondegraded radiographs and from the original, conventional images. The diagnostic accuracy obtained with subtraction images, even if they were made from severely noise-degraded images, was equal or superior to that obtained with the conventional radiographs. This indicates that structured noise, which is reduced by the subtraction procedure, is a predominant, limiting factor in the diagnosis of small periodontal bone lesions. It also suggests that the application of a subtraction technique for the detection of such changes occurring over a period of time can make possible the use of significantly faster imaging systems than those currently employed.     

牙周炎基础治疗后牙槽骨变化的动态观察

为动态观察牙周炎基础治疗后牙槽骨的变化，作者利用数字减影技术对９例牙周炎患者的１０４个齿槽骨邻面位点进行了追踪观察。结果表明：不同个体的牙槽骨对治疗的反应分３种类型；牙槽骨骨量增加的最早时间为治疗后２个月；骨量增加幅度最大为治疗后９～１２个月；骨量有呈指数增加的趋势。