Kr:F准分子激光对牙体硬组织的热效应研究

目的：评价Kr:F准分子激光照射牙齿后，对牙体硬组织的影响。方法；通过测量Kr:F准分子激光照射后牙齿硬组织的温度，并与Nd:YAG激光照射组进行比较。结果：10s,60s时，Kr:F准分子激光组牙齿硬组织的温度升高值明显低于Nd：YAG激光照射组（P＜0．01）。在照射10s-60s时间内，Kr:F准分子激光照射后牙齿硬组织的温度变化值也明显低于Nd:YAG激光照射组（P＜0．01）。结论：Kr:F准分子激光牙齿产热较少。     

Nd:YAG激光对猴牙牙髓的影响

目的：观察Nd：YAG激光对猴牙牙髓的影响，比较牙面涂布60g／L美蓝和经常规硝酸银脱敏后对激光照射效果的影响情况。方法：以1592、3185、4777mJ／mm^23种能量水平的Nd：YAG激光照射3只猴的30个牙面，用组织病理学方法观察牙髓变化情况。结果：1592mJ／mm^2照射组，不论牙面经何种处理，牙髓反应均与对照组相似，为0级；3185mJ／mm^2照射组，牙髓出现轻度改变；大能量、高频率的4777mJ／mm^2照射则出现广泛性成牙本质细胞变性、坏死。照射面色素的存在增加了激光对牙髓的刺激，氨硝酸银加丁香油酚还原成银沉淀，隔绝了外界刺激对牙本质和牙髓的影响，同样参数的Nd：YAG激光造成的牙髓损害在3组中最小。结论：大能量Nd：YAG激光可造成牙髓组织损伤性反应，照射面经不同的处理可影响Nd：YAG激光的照射效果。     

SD大鼠牙髓增龄变化对Nd：YAG激光照射的应激反应观察

目的：观察增龄牙髓对Nd：YAG激光照射的应激反应变化。方法：观察幼年组（6周龄）、成年组（12周龄）、老年组（72周龄）雄性SD大鼠切牙经不同能量密度脉冲式Nd：YAG激光照射后6h牙髓的组织形态学变化,利用图像分析系统对不同年龄大鼠成牙本质细胞中诱导型热休克蛋白（HSP70）表达的平均光密度值进行分析比较。结果：激光能量密度为1433mJ／mm^2和1910mJ／mm^2时,老年组成牙本质细胞中诱导型HSP70的表达强度显著高于幼年和成年组（P〈0．05）;能量密度为2388mJ／mm^2时,老年组成牙本质细胞中诱导型HSP70的表达强度显著低于幼年和成年组（P〈0．05）,且老年组部分成牙本质细胞变性坏死。结论：老年大鼠牙髓对激光刺激的耐受性下降。     

Kr:F准分子激光对釉质表面粘结强度的影响

目的 :探讨在粘接技术中应用Kr:F准分子激光的可能性。方法 :经Kr:F激光照射和酸蚀后的牙齿釉质面 ,分别与窝沟封闭剂粘接 ,比较两组的粘接强度。结果 :Kr:F激光处理组与酸蚀组粘接强度无显著性差异 (p >0 0 5 )。结论 :Kr:F准分子激光可替代化学酸蚀法处理釉质表面 ,并具有操作简便、抗酸力增强等独特的优越性     

Nd:YAG 激光在直接盖髓术中的应用

目的 :观察研究脉冲Nd :YAG激光照射在直接盖髓术中的作用。方法 :选择门诊意外露髓的患者 10 0例 ,随机分为对照组和试验组。对照组采用传统的氢氧化钙直接盖髓术。试验组首先用脉冲Nd :YAG激光 (设置激光脉冲频率为 2 0Hz ,每脉冲能量 40mJ)照射穿髓孔区 5s,再以氢氧化钙封闭穿髓孔。病人于术后 2周、6月、12月分别复诊检查牙髓活力情况 ,记录盖髓术成功率。结果 :12月复诊时对照组成功率 76 % ,试验组成功率 92 % ,统计学分析两者有显著性差异。结论 :适当能量的Nd :YAG激光照射有助于直接盖髓术的成功。脉冲Nd :YAG激光不仅具有清除穿髓孔区牙体组织碎屑、使暴露的牙体组织表面凝固止血、对穿髓孔区灭菌消毒等功能 ,还具有促进牙髓组织细胞再生修复的作用。     

Nd：YAG激光去除陶瓷托槽对兔牙髓组织的影响

目的应用Nd：YAG激光,观察在不同功率、时间等参数下,激光照射辅助去除陶瓷托槽后兔牙髓的组织学变化。方法选择新西兰长耳白兔20只,将其4颗前牙作为实验用牙齿,常规黏结陶瓷托槽。左上前牙机械去黏结,作为对照组;其余3颗牙齿采用激光去黏结,右上前牙激光能量为3 W、3 s（A组）,左下前牙能量为2 W、5 s（B组）,右下前牙能量为5 W、2 s（C组）。去黏结后5 min、1 d、3 d、1周和1月后处死动物,每次处死4只,拔除前牙,制作兔牙髓组织切片。结果与对照组相比,经不同能量激光照射后5 min,兔牙髓组织均出现轻度毛细血管扩张。1 d后,A、B组出现中度毛细血管扩张;C组除有中度毛细血管扩张外,还伴有少量炎细胞浸润。3 d后,B组牙髓症状消失;A组牙髓症状减轻,仍有轻度毛细血管扩张;C组有毛细血管扩张、出血,并伴有炎细胞浸润。1周后,A组毛细血管扩张减轻,基本恢复正常;C组症状仍很明显。1月后,A组牙髓症状消失,C组仍有轻度毛细血管扩张。结论采用能量为3 W、3 s的Nd：YAG激光去除陶瓷托槽,兔牙髓组织不会出现不可逆的组织学变化。     

Kr:F准分子激光处理釉质与酸蚀釉质粘结强度的比较性研究

目的 探讨Kr:F准分子激光处理釉质表面后对粘接强度的影响。方法 牙齿釉质面分别经Kr:F激光照射或酸蚀后,与窝沟封闭剂粘接,比较两组的粘接强度。结果 Kr:F激光处理组与酸蚀组粘接强度间无显著性差异(P>0.05)。结论 Kr:F准分子激光替代化学酸蚀法处理釉质表面具临床可行性和独特的优越性。     

Kr:F准分子激光作用釉质所产生的形态学变化

目的 :探讨Kr :F激光对牙釉质作用的机制及合适的能量参数。方法 :扫描电镜 (SEM)观察六种不同能量密度的Kr:F激光照射釉质表面产生的形态学变化。结果 :Kr:F准分子激光对釉质产生切割作用。随着能量密度的增加 ,由酸蚀状改变到产生光洁熔融的表面。结论 :Kr:F激光产生的不同釉质形态学变化 ,在牙科学领域有着良好的应用前景。     

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。     

Nd: YAG激光对3种树脂水门汀与牙本质粘接强度的影响

目的观察Nd: YAG激光照射前后树脂水门汀-牙本质粘接界面的微观形貌特征,评价Nd: YAG激光对3种树脂水门汀与牙本质间粘接强度的影响。方法选择人离体前磨牙30颗,分为颊、舌两部分,将试件随机分为激光组和对照组。激光组以0.8 W、10 Hz脉冲Nd: YAG激光作用于牙本质表面25 s,联合3种树脂水门汀RelyX ARC、Panavia F和RelyX Unicem充填;对照组直接使用树脂水门汀充填。然后测试剪切强度,在根管显微镜下观察断裂模式并分类。另选人离体前磨牙6颗,按照标准的牙本质粘接面预备后,使用Nd: YAG激光照射3颗牙牙本质表面,并联合充填不同的树脂水门汀,用扫描电镜观察Nd: YAG激光照射前后树脂水门汀-牙本质界面的微观形貌变化。结果
激光照射可以提高自酸蚀树脂水门汀Panavia F和自粘接树脂水门汀RelyX Unicem与牙本质之间的剪切强度（P＜0.05）。激光会降低全酸蚀树脂水门汀RelyX ARC与牙本质间的剪切强度（P＜0.05）。根管显微镜下观察可见：试件断裂大部分发生在树脂水门汀-牙本质界面。扫描电镜观察可见：Nd: YAG激光照射后,全酸蚀亚组和自酸蚀亚组的混合层变薄、树脂突变短且少;自粘接亚组变化不明显,未见树脂突。结论Nd: YAG激光照射后,可提高Panavia F和RelyX Unicem与牙本质的剪切强度,建议临床联合应用。     

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。