软启动照射模式对复合树脂聚合收缩的影响

目的:测定不同光照强度的软启动照射模式下同一种复合树脂的聚合收缩率.方法:采用粘接片(bonded discs)法测定卡瑞斯玛光固化复合树脂(体积38.5 mm3,C值0.47)在不同照射模式(高普40s、高普20 s、高渐进、高脉冲、中普、中渐进、中脉冲、台阶1、台阶2、台阶3)照射3min的聚合收缩率.结果:3种台阶照射模式的聚合体积收缩率均显著大于其他照射模式(P＜0.05);高普20 s模式的聚合体积收缩率显著大于高渐进、高脉冲模式(P＜0.05),但与高普40s相比无显著差异(P＞0.05);中普、中渐、中脉冲照射模式间体积收缩率两两相比均无显著差异(P＞0.05);台阶1照射模式的体积收缩率显著大于台阶2和台阶3(P＜0.05),而后两者无显著差异(P＞0.05).结论:光固化机固有的软启动和脉冲照射模式不能增加树脂的表面流动补偿收缩能力,应用光强更低的前期台阶照射模式则可显著增加树脂的表面流动补偿收缩能力.     

新型环氧树脂聚合体积收缩率及聚合收缩应力初探

目的 评价新型环氧树脂的聚合体积收缩率和聚合收缩应力,为其临床应用提供参考.方法 选用3种复合树脂材料:A组:丙烯酸酯树脂(XenoⅢ-TPH);B组:丙烯酸酯树脂(Clearfil SE bond-Clearfil Majesty Posterior);C组:新型环氧树脂(FiltekTM silorane adhesive-P90).3组复合树脂经光照固化后,用显微CT测量聚合体积收缩率,用万能材料实验机测试聚合收缩应力.结果 A、B和C组复合树脂的聚合体积收缩率分别为(3.38±0.17)％、(1.95±0.37)％和(1.05％±0.09)％;C组最小,与A、B组的差异均有统计学意义(P ＜0.001).A、B和C组复合树脂的聚合收缩应力分别为(3.04 ±0.26)、(3.49±0.46)和(1.54±0.15) MPa;C组最小,与A、B组的差异均有统计学意义(P＜0.001).结论 新型环氧树脂具有优良的低聚合收缩性能.     

数字图像相关法在光固化复合树脂收缩变形测量中的应用

目的:探讨数字图像相关法在研究光固化复合树脂光照收缩变形产生和演化中的价值.方法:6颗新鲜、完整的离体磨牙,随机分为2组,邻面片切平整,制备2.0 mm×2.0 mm×2.0 mm的邻(牙合)面洞形,洞面酸蚀冲洗,涂黏结剂光照,第1组充填3M Z350纳米树脂,第2组充填3M Valux Plus(V.P)通用型树脂.邻面快速制造散斑,固定于微型试验夹中,光照40s,同步数码相机采集表面散斑序列图,以数字图像分析软件计算序列图各像素点水平方向(x)和垂直方向(y)位移、应变,采用SPSS 12.01软件包统计线性收缩率,并对20 s时游离面各点位移进行配对t检验.结果:序列图经处理后,相关系数R均＞0.98.树脂光照40 s内表现为各向异性收缩,2组材料x方向线收缩率分别为0.439％～0.75％ 、0.526％～0.834％,y方向线收缩率分别为0.253％～1.34％、0.355％～1.51％.20 s时,游离面Z350组在x和y方向变形均较V.P组小(P＜0.05).结论:应用数字图像相关法研究光固化复合树脂光照过程中的聚合收缩,能有效动态记录、计算全域收缩变形量,为提高临床使用效果提供依据.     

5种后牙复合树脂耐磨耗性能的体外评价

目的：比较5种后牙复合树脂的耐磨耗性能,探讨影响耐磨耗性能的因素。方法：取Helio-molar HB（A）、Solitaire 2（B）、Filtek P60（C）、Ecusphere－Carat（D）、Tetric Ceram HB（E）5种后牙复合树脂和银汞合金（F）,制成磨耗试样,用显微硬度计测定其表面硬度后,分别置于V型牙科磨耗试验机上,以不锈钢球为对磨偶件、萤石粉为磨耗介质,在磨耗压力为3N的条件下对试样摩擦6万次;然后,用三维形貌仪测定试样的体积磨损量和磨损面粗糙度,SEM观察其磨损表面形貌。结果：各材料体积磨损量由小到大依次为：F＜C＜B≈E≈A＜D（P＜0．05）;各材料硬度由低到高依次为：A＜B＜D＜E＜C＜F（P＜0．05）;C、D磨损表面较为平整,呈现典型的磨料磨损特征,A、B、E表面较为粗糙,有明显的材料疲劳磨损特征;各树脂的体积磨损量和磨损面粗糙度均与其硬度值呈负相关性（P＜0．05）。结论：后牙复合树脂的硬度越高,耐磨耗性越好,磨损面粗糙度越低;超微填料含量多者主要表现为疲劳磨损,超微填料含量少者主要表现为磨料磨损。     

纳米填料复合树脂抛光后表面粗糙度及微结构的比较

目的评价纳米填料复合树脂抛光后表面粗糙度及微结构。方法4种纳米填料复合树脂制备成7mm×7mm试件,在一致的条件下抛光后测定表面粗糙度,并与同样条件下抛光后的微填料复合树脂Z250比较。使用扫描电镜（SEM）及原子力显微镜（AFM）观察表面性状。结果纳米填料复合树脂表面粗糙度较混合微填料树脂Z250低（P〈0．01）,前者中Z350和Grandio较Ceram．XDuo和Majestv低（P〈0．05）。SEM观察结果显示,与混合微填料树脂Z250比较,纳米填料复合树脂表面质地均匀．填料颗粒脱落造成的凹坑小而少。AFM下可见纳米填料复合树脂高出基准平面的颗粒或低于基准平面的凹坑的平均高度较混合微填料树脂Z250小（P〈0．01）;在纳米填料复合树脂中Z350和Grandio较Ceram-XDuo和Majesty小（P〈0．05）。结论纳米填料复合树脂较微填料复合树脂具有更光滑均质的微表面和更低的表面粗糙度．纳米填料复合树脂中Z350和Grandio具有更光滑均质的微表面．     

8种复合树脂磨耗性能和硬度的研究

目的体外测定8种复合树脂的体积磨损量和硬度,评价其耐磨耗性能。方法选择Durafill VS、Filtek A110、Charisma、Ceram-X、Filtek Z350、FS-2、Filtek P60和Tetric Ceram HB 8种复合树脂,分别制备8mm×6mm×2mm的树脂片,并用自凝树脂包埋,测定表面硬度（维氏）。将试样固定在往复滑动球-片式磨耗试验机上,以萤石粉糊剂作为磨耗介质,磨耗3万次后用三维形貌扫描仪测定复合树脂表面磨痕的体积,统计学分析复合树脂的硬度与其体积磨损量的相关性及各个复合树脂体积间磨损量的差异,SEM观察分析磨损面。结果 8种复合树脂的硬度顺序为：P60≈Z350〉A110≈Tetric HB〉FS-2≈Ceram-X〉Charisma〉Durafill。Z350的磨损量最小（0.68±0.05）mm3,其次是P60（1.11±0.06）mm3,随后是Charisma（1.50±0.17）mm3、Durafill（1.64±0.49）mm3、FS-2（1.75±0.32）mm3及A110（1.84±0.37）mm3,Ceram-X（2.09±0.36）mm3和Tetric HB（2.56±0.48）mm3的磨损量较大。所测复合树脂的硬度与其体积磨损量之间无相关性（r=-0.55）。结论复合树脂的耐磨耗性能与其硬度无关,而与不同材料品牌关系密切。     

复合树脂收缩应力测量系统初探

目的 探讨复合树脂聚合收缩应力的测试方法及树脂基质对收缩应力的影响.方法 使用模拟临床条件下的聚合收缩应力测量系统,测量两种以新型单体为基质的复合树脂(P 90、维纳斯钻石)和传统基质复合树脂(Z350和卡瑞斯玛)光照开始后收缩力值变化情况,并测得复合树脂在光照后300 s时的聚合收缩应力值.结果 两种采用新型基质的复合树脂在光照后300 s时的收缩应力显著低于传统基质复合树脂,4种被测复合树脂收缩应力的大小依次为Z350[ (4.08 ±0.12)MPa]＞卡瑞斯玛[(1.92 ±0.10)MPa]＞维纳斯钻石[(1.16 ±0.03)MPa] ＞P90[(0.94±0.04)MPa] (P ＜0.05).且两种新型复合树脂的聚合收缩反应速率较缓慢.结论 本测量系统可实时有效监测复合树脂固化过程中收缩应力的变化过程;以新型单体代替传统树脂基质是开发低收缩复合树脂的有效途径.     

充填厚度对光固化大块复合树脂充填效果的影响

目的 研究充填厚度对大块复合树脂充填效果的影响.方法 2种大块充填树脂Filtek Bulk Fill Posteri-or(FBF)和Tetric N-Ceram Bulk Fill(TBF)为实验组,2种传统光固化复合树脂Filtek Z100(Z100)和Spec-trum TPH(ST)为对照,测试不同固化厚度...     

2种光固化灯固化对3种不同复合树脂聚合收缩的影响

目的:比较2种光固化灯对3种复合树脂聚合收缩的影响。方法:相移投影栅形貌测量仪测量Z100、Z250、AP-X等3种复合树脂在卤素灯和发光二极管固化灯开始固化后50s及开始固化后400s的树脂聚合收缩量。使用SPSS12.0软件包对QTH及LED固化组聚合收缩量进行单因素方差分析。结果:在开始固化后50s和400s,QTH固化灯和LED固化灯固化Z100、Z250树脂产生的聚合收缩量有显著差异,QTH固化灯固化Z100、Z250树脂产生的聚合收缩量显著大于LED固化灯(P<0.05),QTH和LED固化灯固化AP-X树脂产生的聚合收缩量则无统计学差异(P>0.05)。结论:LED及QTH固化灯固化Z100、Z250树脂产生的聚合收缩影响有显著差异(P<0.05),LED及QTH固化灯固化AP-X产生的聚合收缩无显著差异(P>0.05)。     

含长链烷基季铵盐的纳米抗菌无机填料的合成及其在牙科复合树脂中的应用研究

目的 设计合成新型的含长链烷基季铵盐的纳米抗菌无机填料,以赋予牙科复合树脂更优良的抗菌性能。方法 在分子设计和筛选的基础上,制备了长链烷基季铵盐修饰的纳米抗菌二氧化硅填料,并对填料的抗菌性能进行评价。为进一步提高抗菌填料与树脂的结合力,采用硅烷偶联剂对抗菌填料表面进行了处理,并用红外光谱法对其结构特征进行分析;然后将新型纳米抗菌无机填料加入牙科复合树脂中,观察其在复合树脂基体中的分散情况,同时与商品化的Tetric N-Ceram纳米瓷化复合树脂进行对比;并以变异链球菌为对象,研究复合树脂的抗菌性能。结果 长链烷基季铵盐成功接枝到纳米二氧化硅颗粒表面;新型纳米抗菌无机填料的抗菌性能优于含短链烷基季铵盐的抗菌无机填料;偶联处理后的纳米抗菌无机填料在树脂基体中分散均匀,与树脂结合紧密,与Tetric N-Ceram纳米瓷化复合树脂类似;改性后的复合树脂抗菌性能良好。结论 含长链烷基季铵盐的纳米抗菌无机填料抗菌性能良好,经过表面偶联处理后可以很好地与牙科复合树脂共混,提高了牙科复合树脂的抗菌性能。     

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。