Nd：YAG激光照射与机械根面平整的比较研究

应用扫描电镜比较了单独机械根面平整，不同能量的脉冲Ｎｄ：ＹＡＧ激光单独照射，机械根面平整前、后激光照射正常离体牙根引起的形态变化。结果发现：根面平整可引起根面出现许多器械刮痕，放大后呈许多不规则碎屑组成的玷污层；激光照射可清洁，干燥牙根表面，蒸发玷污层；表面呈熔岩状改变；根面平整前、后激光照射，大部分区域呈激光照射后特征性结构变化，有些区域表面有利痕并存在牙骨质剥脱。本文讨论了上述结果的临床意义及     

激光照射对牙髓细胞形态的影响

不同的激光能量可以产生不同的生物效应．本文应用扫描电镜、倒置显微镜观察不同能量、不同频率的激光能量设置对牙髓细胞形态的影响，结果表明：１００ｍｊ２０Ｈｚ、６０ｍｊ４０Ｈｚ、４０ｍｊ５０Ｈｚ以上的能量设置可使牙髓细胞产生裂纹、结构模糊．结论：Ｎｄ：ＹＡＧ激光的能量、频率均可影响牙髓细胞形态     

脉冲Nd：YAG激光照射牙本质过敏牙后的扫描电镜观察

本研究应用新鲜离体人牙将面作成牙本质过敏牙模型，以三种不同输出能量的脉冲Ｎｄ：ＹＡＧ激光照射后，用扫描电观察牙本质的形态变化。结果发现，过敏牙面经适当的激光一，牙本质间质产生的熔融层能够严密地封闭牙本质管口，牙本质表面经激光照射后不出现裂纹和球形突起。本研究为临应用脉冲Ｎｄ：ＹＡＧ激光的脱敏治疗提供了形态学证据，本文还就激光能量与牙髓的关系以及有关的临床问题进行了较详细的讨论。     

3种方法根面平整对牙根表面形态影响的扫描电镜观察

目的：本文用扫描电镜观察比较Gracey刮治器、Vector超声治疗仪和Er：YAG激光根面平整引起牙根表面形态学改变。方法：24颗因重度牙周炎拔除牙齿随机分为3组。A组,Gracey刮治器组,B组Vector超声治疗仪组,c组Er：YAG激光组。扫描电镜观察牙根表面形态。结果：A组牙根表面可见不规则的深沟和空洞样缺损。B组牙根表面清洁光滑,未见工作尖的痕迹,颗粒状结构覆盖于牙骨质层。c组牙根表面形态几乎没有改变,高倍镜下表层组织熔融呈火山状。结论：Er：YAG激光和Vector超声治疗仪都能有效地去除龈下牙石,而且与Gracey刮治器相比能更好的保存牙根表面健康组织。     

钕钇铝──石榴石激光对牙本质表面形态影响的扫描电镜观察

对２０例离体无龋恒牙牙本质表面作钕钇铝——石榴石（Ｎｄ：ＹＡＧ）激光照射，在扫描电镜（ＳＥＭ）下观察照射后牙本质的表面形态变化。结果表明：Ｎｄ：ＹＡＧ激光照射可使牙本质表面粗糙模糊，牙本质小管口形态破坏，并且随着照射时间增长，或照射功率加强，牙本质表面的这种改变增大，提示：Ｎｄ：ＹＡＧ激光对牙本质表面结构有累加性熔作用。     

不同能量Er,Cr∶YSGG激光照射对牙体硬组织抗酸作用的体外研究

目的:探讨Er,Cr∶ YSGG激光照射能量与牙体硬组织抗酸性之间的关系.方法:采用2.5、3.5、5W激光照射牙釉质样本,2、3、4W激光照射牙本质样本.经0.1 mmol/L乳酸液浸泡24 h后检测钙磷溶出量,能谱仪检测样本表面钙磷原子百分比,SEM观察表面形态.结果:除2.5W牙釉质组,其余牙釉质和牙本质实验组钙磷溶出量显著低于对照组(P＜0.05),实验组间无明显差异.激光照射后牙釉质钙磷比增加,牙本质钙磷含量均无变化.SEM观察显示实验组样本表面粗糙,釉柱间隙增大,牙本质小管口周牙本管突出成袖口状.结论:一定能量的Er,Cr∶YSGG激光照射可使牙硬组织抗酸性提高.     

不同参数的Er：YAG激光离体牙窝洞预备的形态学观察

目的：观察Er：YAG激光对离体人牙进行窝洞预备后的形态学改变,比较不同的能量设置及不同的水气比作用下的预备效果。方法：将10个无龋的离体磨牙随机分为5组（n＝2）,分别用不同Er：YAG激光参数进行窝洞预备。扫描电镜下观察牙釉质和牙本质的形态学改变。结果：经Er：YAG激光照射后,牙釉质呈现出一个粗糙不平的表面,牙本质层清洁,小管开放。在总功率相近的情况下,当水冷却降到50％或切割牙釉质时脉冲能量增加到700 mJ、切割牙本质时脉冲能量增加到400 mJ时,牙釉质及牙本质表面可发生部分熔融改变。结论：Er：YAG激光使用合适的参数进行牙体硬组织的切割安全有效,但在功率相近的情况下,水冷却不足或能量过大（牙釉质＞700 mJ,牙本质＞400 mJ）可损伤牙体组织。     

脉冲Nd:YAG激光照射对犬牙髓的影响

目的：探讨Nd：YAG激光对牙髓的安全阈值。方法：选择4条健康的本地杂种犬，先进行过敏模型制备，随机分为3组，分别给予：33J／cm^2、56J／cm^2和111J／cm^2激光照射，按照即刻、3d、7d、1个月4个时间段处死试验犬，实验牙经过固定、脱钙后，进行组织切片、光镜观察、病理分级。结果：牙髓反应均在3级以下，随激光照射能量的升高牙髓组织病理变化明显。在33～56J／cm^2之间，牙髓组织正常或反应轻微。结论：应用Nd：YAG激光进行牙齿过敏治疗时，其热效应可能对牙髓组织产生影响，33～56J／cm^2的激光能量不会对牙髓组织产生损害，能量较高将导致牙髓组织炎症，所以33～56J／cm^2的能量密度应为进行当次牙齿过敏治疗的安全阈值。     

激光与磷酸麟蚀牙釉质表面粗糙度及剪切力的比较

目的 对激光和磷酸刻蚀牙釉质进行比较，探讨激光刻蚀是否可作为酸蚀牙釉质表面的一种替代方法。方法 以４２颗离体上颌双尖牙作为研究标本，对其唇面牙釉质表面分别进行不同能量的激光刻蚀和３７％磷酸刻蚀处理，同时模拟光固化治疗。体视显微镜和扫描电镜下观察牙釉质表面粗糙度及形态特征，以ＣＬ－Ｃ测力仪对光固化材料粘结强度的剪切力进行测试。结果 牙釉质表面粗糙度与激光能量密度呈正相关性。ｐｐｓ２０Ｈｚ７５～８７ｍ     

脉冲Nd：YAG激光牙龈切除伤口愈合的组织学观察

本文以不同能量参数的脉冲Ｎｄ：ＹＡＧ激光照射切除新西兰兔牙龈组织，以手术切除作对照，手术后２，７，１４，２１天取材。观察牙龈伤口愈合过程的组织病理学变化。结果显示：激光组的病理反应随伤口愈合过程由表及里表现出三层结构，即炭化坏死层、炎症渗出层和修复性肉芽组织层，激光组愈合早期坏死层和渗出层较对照明显，牙龈上皮再生覆盖延迟，肉芽组织形成较慢。高能量激光对牙龈组织的损伤作用较低能量的大。１４天后，激光     

Evidence of the validity of a model of determinants of quality of restorative dental care

A model describing the relationship between self-reported quality of restorative dentistry and dentist characteristics for 119 Montana general dentists is presented. The best predictors formed a significant model explaining 22% of the variance of the quality measure. Results are contrasted with a previous estimation of the model for 102 Washington general practitioners. Evidence for the external validity of the model is presented.     

Experimental evidence of formation of imines in the course of reduction of hydrazones

The reduction of hydrazones is generally suggested to proceed through a reductive cleavage of the nitrogen–nitrogen bond followed by a reduction of the carbon–nitrogen bond. This sequence of reduction processes is here supported for fluorenone (V) and benzophenone (VI) hydrazones as well as by a comparison of the reduction of fluorenone and benzophenone hydrazonium ions (I,III) with corresponding imines (II,IV). Another proof of the presence of imines as intermediates is the splitting of four-electron waves of hydrazones V and VI and hydrazonium ions I and VIII into two waves at pH < 2. This has been interpreted as due to differences in slopes dE_1/2/dpH and pK_a-values of protonated hydrazine derivatives on one side and corresponding imines on the other. In this pH-range imines formed in reductions of VI and VIII are reduced in a single two-electron wave, those of I and V in two one-electron steps. Fluorenone imine (II) is sufficiently stable to allow recording of time-independent current–voltage curves between pH 6 and 11. In this pH-range the imine (II) is reduced in two one-electron steps. Benzophenone imine (IV) has been found stable between pH 4.6 and 12. At pH 4.6–8 the reduction of the imine IV takes place in a single two-electron step, at pH 8–12 in two one-electron steps. Final proof of the initial cleavage of the N–N bond is presented by comparison with the reduction of nitrones.     

不同剂型玻璃离子水门汀溶解性比较研究

目的:研究、比较不同剂型玻璃离子水门汀的溶解性和表面微观形态改变,为临床使用提供依据.方法:将3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)及GC玻璃离子水门汀(双糊剂型)分别在人工唾液中浸泡30 d,冷热循环15000次,烘干测重,比较前后质量变化,计算溶解率,并用扫描电镜观察表面微观改变.结果:不同剂型的玻璃离子水门汀溶解率由高到低分别为3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(双糊剂型).3种玻璃离子水门汀经浸泡溶解后,SEM扫描表面微观形态可观察到GE玻璃离子水门汀(双糊剂型)表面形态改变较少,其他2组玻璃离子水门汀表面微观改变较多.结论:双糊剂型玻璃离子水门汀理化性能及溶解率均低于传统水粉剂型,是未来临床修复治疗的的良好选择.     

Evaluation of efficacy of chemiluminescence for diagnosis of leukoplakia

ObjectiveLeukoplakia is the most common potentially malignant disorder preceding oral cancer. Chemiluminescence has been developed as an adjunct to conventional examination for the diagnosis of these potentially malignant disorders. This study was conducted to assess the efficacy of chemiluminescence in the diagnosis of leukoplakia and to compare the results with histopathological examination.Study designA total of 50 patients with leukoplakia were included from the outpatients attending the Department of Oral Medicine and Radiology, Dental Hospital, Bengaluru, Karnataka, India. These patients were subjected to conventional oral examination followed by chemiluminescent examination with Vizilite (Zila, Fort Collins, CO, USA) and biopsy for histopathological confirmation.ResultsThe sensitivity, specificity, positive predictive value, and negative predictive value of chemiluminescence were 93.75%, 55.56%, 78.95%, and 83.3%, respectively. The overall accuracy of chemiluminescence was 80%. A statistically significant association was observed between histopathology results and chemiluminescence results.ConclusionAlthough it is an easy, safe, minimal time consuming, and noninvasive technique, it has only adjunctive utility and it does not replace biopsy for the diagnosis of leukoplakia.     

颌骨动静脉畸形的栓塞治疗

目的：总结直接穿刺结合经血管内介入栓塞治疗颌骨动静脉静脉畸形的经验。方法：收治凳骨动静脉畸形患者6例,均进行了介入栓塞治疗。采用的栓塞材料为附凝血棉纤毛的螺圈,聚乙烯醇泡沫微粒和二氰基丙烯酸对丁酯。数字减影颈动脉造影在PHILIPSV300下完成。结果6例颌骨动静脉畸形患者中4,例急性出血得到了快速、有效控制,1例慢性渗血的右下 骨动静脉畸形患者,介入栓塞治疗,拔除松动的右下凳第一磨牙,有效地控制了出血,另1例伴局部软组织搏动性膨隆的上凳骨动静脉畸形患者,介入治疗后膨隆的搏动性得到明显改善,栓塞治疗后分别随访3－24个月,均未发现有口腔内渗血或出血。随访的X线片上,病灶区可见新骨形成。结论：局部穿刺结合经血管内介入栓塞治疗颌骨动静畸形是一种安全、有效的治疗方法。     

正畸患者切牙影像失真发生情况分析

目的研究正畸患者曲面体层片上的切牙影像失真发生情况，并分析其原因。 方法从中山大学附属口腔医院放射科影像数据库中选取500例正畸患者的曲面体层片和头影测量侧位片，所有曲面体层片均采用咬合杆投照，分别从切牙牙体影像放大、缩小、牙根变短、根尖模糊等评价指标分析上下颌切牙影像失真的发生情况，在头影测量侧位片上测量中切牙根尖-对颌切牙切缘的距离，探讨切牙影像失真发生的原因。采用SPSS 19.0统计软件对所得数据进行统计学检验。 结果500例患者中，切牙牙体影像正常者共417例，切牙牙体影像失真者共83例，影像失真发生率16.6%，其中切牙牙体影像放大17例、牙体影像缩小0例、牙根变短30例，牙根影像变短伴模糊36例。影像失真患者的根尖-切缘距离大于影像正常的患者，差异有统计学意义（F = 5 187.18，P = 0）；影像失真患者的覆盖值大于影像正常的患者，差异有统计学意义（F>477，P = 0）。 结论严重牙颌面畸形如反 、深覆盖是导致曲面体层片的切牙影像失真的主要原因之一。     

Design of clinical trials of traditional therapies of periodontitis

The present paper on the design of clinical trials of periodontal therapy first addresses the issue of the etiology of periodontal disease. It is suggested that most if not all forms of destructive periodontal disease are caused by microorganisms and that there are different forms of disease with different microbial etiologies. The progressive nature of destructive periodontal disease is subsequently discussed and it is emphasized that, in a given patient, periodontal sites which show signs of inflammation and attachment loss may not over a period of several months and years show further sign of attachment loss. The present methods of assessing periodontal disease do not allow us to discriminate between potentially active and inactive sites in untreated patients. The significance and variability of indicators of periodontal disease such as bleeding on probing, probing pocket depth and probing attachment level measurements are discussed. The errors inherent in the various measurements are analyzed and suggestions are presented describing how alterations in any of the above parameters could be identified and presented in a clinical trial. Of concern for the statistical analysis of clinical data of periodontal disease is the definition of the "experimental unit". For a number of years, the "experimental unit" in periodontal trials was the patient. It is clear, however, that different sites within the same individual show different patterns of disease progression and lesion morphology and often respond differently to periodontal therapy. Statistical analyses must consequently be designed which recognize differences in site-to-site infection and lesion morphology within a common host. Until such analyses are available, the investigator should be wary of pooling data within the same individual, since such pooling may obscure meaningful alternatives which may take place in individual periodontal sites. Some goals of periodontal therapy are subsequently identified. 4 goals are discussed more in detail, namely: to establish conditions which will allow the patient to maintain a dentition without further breakdown of the periodontium; to reduce pocket depth to establish an anatomy in the dentogingival region which with proper maintainance care will prevent the re-establishment of the subgingival infection; to gain attachment as a result of treatment; to assess the effect of a certain chemotherapeutic agent on periodontal disease.     

正常青年Monson球面半径的测量研究

目的测量正常青年Monson球面半径。方法选择60名(男30名,女30名)正常青年制取全口印模,应用立体摄影成像的原理与方法对Monson球面半径进行测量和统计学处理。结果Monson球面的半径平均为10.173 cm,大于理论值10.160 cm,差异有显著性(P<0.01);男、女性球面半径差异无显著性。结论本实验所得到的数据可作为全口义齿修复中记录颌位关系的一个参量。     

鼻测量法的进展

唇裂术后继发畸形是指唇裂修复术后,仍遗留或继发于手术操作和生长发育变化而表现出来的一类畸形[1]。包括唇畸形、鼻畸形和颌骨畸形。其修复较原发性唇裂修复更复杂,更灵活多变。而导致其修复复杂性的一个重要原因即是局部组织结构复杂变异和缺乏可靠的三维测量手段[2],鼻畸形     

口底癌34例临床分析

目的探讨口底癌的临床特性、治疗方法及预后。方法对我院自1992—2002年住院治疗的34例口底癌患者进行回顾性分析。结果34例口底癌患者中,男28例(82.4%),女6例(17.6%),男女比为4.7∶1,平均发病年龄58岁。发病部位:前口底22例(64.7%),后口底12例(35.3%)。淋巴结转移率41.2%。单纯手术组、化疗加手术组、放疗加手术组、化疗加手术加放疗组的5年生存率分别为45.5%、60.0%、50.0%、62.5%。结论口底癌以中老年患者好发,男性居多。易发生淋巴结转移,综合疗法疗效较好。