3D整合牙颌模型在无托槽隐形治器设计中的应用

目的 探讨将3D整合牙颌模型应用于无托槽隐形矫治器设计,以便精确控制牙根在颌骨中的移动.方法 将基于锥形束计算机断层扫描( CBCT)的牙颌模型和基于机构光扫描的牙冠模型自动配准,建立能精确显示牙列、咬合、牙根及颌骨的3D整合牙颌模型.在3D整合牙颌模型上进行模拟排牙和虚拟矫治,然后应用激光快速成型技术制作无托槽隐形...     

虚拟排牙的牙根外露检验性研究

目的检验以三维牙冠模型为基础虚拟排牙,当上下颌牙冠在虚拟矫治达到良好排列和咬合时,有无牙根外露情况以及好发位置。方法选择15例成人骨型Ⅰ类拔牙矫治病例作为研究样本,以其牙列石膏模型的激光扫描三维数字化模型为基础进行虚拟排牙,使上下颌牙冠达到良好排列和咬合。同时所有研究样本进行头颅CBCT扫描,采用软件配准的方法获得激光扫描模型和CBCT扫描模型的3D整合牙颌模型,将3D整合牙颌模型的牙冠移动到虚拟排牙后的位置,使3D整合牙颌模型的牙冠与虚拟排牙的牙冠完全一致,此时显示随牙冠一起移动的牙根,观察牙根是否移动到颌骨的骨皮质外。结果所有样本在虚拟排牙模型中,至少有一处牙根外露,出现牙根外露的比例为100%,其中出现牙根外露比例较高位置依次为上颌尖牙、上下颌切牙和第一磨牙处。结论以数字化牙冠模型为基础的虚拟排牙,当上下颌牙冠在计算机排牙中达到良好排列和咬合时,并不能完全避免牙根外露于骨皮质外。     

包括牙根三维牙颌模型在舌侧间接粘接系统中的应用

目的 探索将带有牙根和颌骨的排牙模型应用于计算机辅助设计和制作的舌侧矫治技术间接粘接系统中,并试用于临床.方法 将三维CT图像和层析图像进行整合,获得包括牙根和颌骨的三维模型.在整合模型上进行计算机辅助设计和制作的舌侧矫治技术模拟排牙和托槽定位,并通过转移托盘粘接到患者口内.结果 排牙模型达到良好的牙冠和牙根的三维排列,托槽在间接粘接转移托盘中就位良好.结论 本研究成功地将带有牙根和颌骨的数字化排牙模型与舌侧矫治技术间接粘接系统相结合,为治疗后牙根不平行、骨开裂、骨开窗等问题提供了解决途径.     

包括牙根三维牙颌模型在舌侧间接粘接系统中的应用

目的 探索将带有牙根和颌骨的排牙模型应用于计算机辅助设计和制作的舌侧矫治技术间接粘接系统中,并试用于临床.方法 将三维CT图像和层析图像进行整合,获得包括牙根和颌骨的三维模型.在整合模型上进行计算机辅助设计和制作的舌侧矫治技术模拟排牙和托槽定位,并通过转移托盘粘接到患者口内.结果 排牙模型达到良好的牙冠和牙根的三维排列,托槽在间接粘接转移托盘中就位良好.结论 本研究成功地将带有牙根和颌骨的数字化排牙模型与舌侧矫治技术间接粘接系统相结合,为治疗后牙根不平行、骨开裂、骨开窗等问题提供了解决途径.     

偏颌患者虚拟排牙的根骨关系研究

目的 通过对比采用传统牙冠模型与根骨数字化的三维整合模型进行虚拟排牙的牙根位置,探讨根骨信息在虚拟排牙中的重要性.方法 选择骨性偏颌患者11例.获取治疗前口内扫描牙冠数据,即治疗前传统牙颌模型,将CBCT根骨信息与传统牙颌模型配准、整合得到治疗前三维整合模型.由专业排牙技师1名分别采用传统牙颌模型与三维整合模型进行虚拟...     

双丝弓个性化舌侧托槽的计算机辅助设计

目的实现一种个性化托槽的计算机辅助设计,以便在临床矫治中显著减小前牙控根力,并且能够应用于拔牙病例。方法在包括患者牙根的整合牙颌模型上进行虚拟排牙,在排牙后的模型上绘制直丝弓和设计双丝直丝弓托槽,托槽通过托槽体的厚度补偿来实现弓丝的直丝化,在托槽上设计双槽沟,主槽沟为方槽沟,辅槽沟为圆槽沟,在主槽沟用方丝虚拟定位托槽后,用计算机辅助设计和制作的个性化托槽,将托槽的虚拟位置转移到患者牙齿上的实际粘接位置进行矫治。结果与方丝控根相比,双丝控根矫治力显著减小;唇侧或舌侧矫治时可以使用直丝弓,简化了临床弓丝弯制;虚拟排牙基于3D整合牙颌模型,可以在虚拟排牙中避免牙根的骨开裂、骨开窗和明显不平行。结论本研究为双丝弓个性化托槽的临床应用奠定了基础。     

数字化整合模型和激光快速成型技术在舌侧间接粘接系统中的初步应用

目的探索应用数字化整合模型和激光快速成型技术制作舌侧托槽间接粘接托盘,并试用于临床。方法应用激光扫描的牙冠与CT重建的牙根和颌骨整合,建立包括牙冠、牙根和颌骨的三维数字化模型,在整合模型上进行模拟排牙和托槽定位,应用激光快速成型技术直接输出间接粘接转移托盘。结果排牙模型达到良好的牙冠和牙根的三维排列,托槽在间接粘接转移托盘中就位良好,并且通过转移托盘粘接到患者口内。结论本研究将带有牙根和颌骨的数字化排牙模型和激光快速成型技术与舌侧矫治技术间接粘接系统相结合,并将其初步应用于临床。     

数字化整合模型技术在DamonQ自锁托槽间接粘接中的初步应用研究

目的探索应用数字化整合模型进行托槽虚拟定位,利用计算机辅助制造托槽间接粘接转移托盘,并试用于临床。方法应用激光扫描的牙冠与CBCT重建的牙根和颌骨整合,建立包括牙冠、牙根和颌骨在内的三维数字化牙颌模型,在整合模型上利用OrthoRx软件进行托槽虚拟定位,并制作托槽间接粘接转移托盘,在临床上通过转移托盘粘接托槽进行矫治。结果OrthoRx软件的托槽虚拟定位,其排牙效果良好,计算机辅助制造产生的间接粘接转移托盘可将托槽转移至患者口中,且托槽粘接稳固。结论 OrthoRx软件可进行托槽在牙面上的虚拟定位,并可呈现排牙后的效果,通过计算机辅助可设计出用于托槽定位的个体化转移托盘,可应用于临床上。     

三维冠根整合数字化模型在口腔临床中的应用研究

目的建立牙齿三维冠根整合数字化模型并进行虚拟排牙,探讨其在口腔临床中的应用。方法获取15例患者锥形束CT(CBCT)的全牙列模型和结构光的牙冠模型,行迭代最近点算法对两种模型进行全局配准,在最佳匹配后截取CBCT牙根和基于结构光扫描的牙冠整合成新的牙齿模型。利用自行研发软件Teeth Arrangement对整合后的牙齿模型按照理想标准进行排列并导入颌骨进行在线验证。最后采用同行评估等级(peer assessment rating,PAR)指数评价排牙效果。结果 15例患者的结构光扫描模型与CBCT配准偏差数据符合正态分布,上颌配准偏差为(0.135±0.015)mm,下颌配准偏差为(0.130±0.022)mm。15例患者的排牙模型导入颌骨中,全部出现了不同程度的牙根突出颌骨。采用PAR指数对排牙前数字化模型与石膏模型错程度分析,两者具有高度一致性(ICC> 0.800)。全部患者排牙前后模型PAR加权值减少90%以上,排牙前后效果比较为改善;2/3患者PAR加权值减少22分以上,排牙前后效果比较为极大改善。结论将牙齿三维冠根整合数字化模型应用到口腔临床具有可行性及必要性。     

包括牙根三维牙颌模型重建系统的研究

目的获得带有牙根和颌骨的数字化排牙模型,以期纳入牙根和颌骨进行全面三维诊断和治疗。方法将三维螺旋CT图像和层析图像进行整合得到包括牙根和颌骨的三维模型,并在整合模型上进行计算机模拟排牙。结果获得含有牙根和颌骨的三维牙颌模型,在数字化模型上达到牙冠齐整、牙根平行、无牙根外露的排牙效果。结论本研究成功建立包括牙根和颌骨的三维排牙模型,为将牙根和颌骨纳入诊治提供基础。     

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.     

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.     

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.     

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.     

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.     

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。     

Electrodeposition of bilayers of dithiols

We report an electrochemical method to form a bilayer of dithiol. The cyclic voltammogram of the oxidative deposition of an aromatic dithiol on gold from an alkaline aqueous solution reveals two current peaks separated by more than 400 mV. The integrated charge of the oxidative current peak (B) at the most positive potential is twice that of the other oxidative current peak (A). These two oxidative current peaks were characterized by differential capacitance and electrochemical quartz crystal microbalance (EQCM) measurements. A decrease of the capacity by a factor of two, and an increase of the EQCM frequency change by a factor of two were observed when the potential was scanned from a value where only the first oxidative peak (A) is obtained, to a potential where both oxidative current peaks (A and B) are obtained. Infrared spectra show that the aromatic dithiols adsorb vertically at potentials corresponding to the current peak A and they become tilted for potentials corresponding to the current peak B. The simple relationships between the properties of the two oxidative current peaks are found to be compatible with a step-wise oxidative deposition of a bilayer of dithiol.     

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。     

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。