光敏复合树脂固化前后的颜色变化

目的:本实验测试了4种光固化复合树脂固化前和固化后的色度值变化.方法:将树脂制成直径10 mm,高10 mm的园柱型试件,应用美能达CS-321便携式色差仪测试TPH,Sculpt It,Durafil,Charisma四种光固化复合树脂固化前后的色度值L*、a*、b*值,根据色差公式△E＝[(△L*)2 (△a*)2 (△b*)2]1/2,计算树脂固化前后的颜色变化值△E.结果:4种光固化复合树脂的27种色调树脂在固化后都发生了较显著的颜色变化,色差值△E在4.66至15.11个色度单位之间.TPH、Sculpt IT、Charisma树脂色度值L*、b*值降低,a*值变化不大;Durafil树脂色度值L*、b*值升高.结论:4种光固化复合树脂在固化后颜色都发生了一定程度的变化.     

E-max和IPS-EMPRESS Ⅱ全瓷贴面对变色牙颜色改善的研究

目的:观察对比E-max和IPS-EMPRESSS Ⅱ两种全瓷贴面对变色牙颜色改善的修复效果,为临床应用提供参考。方法:对36颗变色上前牙分别采用E-max和IPS—EMPRESS Ⅱ全瓷贴面修复。用Shade-Eye-NCC电脑比色仪分别测定修复前牙齿、贴面就位(无试色糊剂)和试粘接(分别用WOT和Tro试色糊剂)及最后粘接后两种修复体唇侧的中1/3处的L*、a*、b*值,根据色差公式△E=[(△L*)2+(△a*)2+(△b*)2]1/2,对比两种瓷贴面对变色牙的修复效果,为临床应用提供参考。结果:IPS-EMPRESSSⅡ全瓷贴面粘接后与牙体预备前的色差值为7.9960,粘接后与试戴(无试色糊剂)的色差值为2.3906,粘接后与试戴(有试色糊剂)的色差值为1.6578。E-max全瓷贴面粘接后与牙体预备前的色差值为8.2428,粘接后与试戴(无试色糊剂)的色差值为1.4638,粘接后与试戴(有试色糊剂)的色差值为1.2596。两组全瓷贴面试戴后(无试色糊剂)、试粘接(有试色糊剂)、粘接后与基牙牙体预备前△E*在统计学上差异有显著性,两组全瓷贴面修复前后的的L*、a*、b*值之间有统计学差异,修复后的L*增大,a*、b*值减少。试粘接后L*值和b*值增大,a*值减少。修复后的L*、a*、b*值与贴面自身相比存在差异,修复后的L*值偏小,a*、b*值偏大。两组瓷贴面在采用WOT糊剂粘接后L*值、b*值最大,与Trt组比,差异均有统计学意义。结论:E-max全瓷贴面比IPS-EMPRESSSⅡ全瓷贴面更有效改善变色牙的颜色,IPS-EMPRESSSⅡ全瓷贴面粘接后较试戴(无试色糊剂)明亮度降低比E-max瓷贴面明显。     

厚度和遮色剂对Artglass颜色的影响

目的：测量Artglass DA3材料的标准色度及无限光学厚度，分析厚度和遮色剂对Artglass色度的影响。方法：测色仪器使用美能达CS-321型便携式色差仪。使用CIE L*a*b*比色系统描述试件颜色。△E表示两颜色之间的色度差异，由以下公式计算得出：△E=[(△L)^2 (△a)^2 (△b)^2]^1/2，将△E=1．5NBS(National Bureau of Standards)作为肉眼可察觉两物体颜色差异的界限值。制作厚度为4．0mm的Artglass试件，两片叠放，测量其色度作为标准色度。再用色差仪测试厚度，由4．0至0．5mm、每两组厚度间隔为0．25mm的15组试件在标准白板和金属底板上的色度，计算色差。铸造金属底板，涂布遮色剂，在其上分层堆塑3．5mm厚的Artglass材料，依次磨去0．25mm后测试其色度。结果：Artglass DA3色材料的标准色度值为L*61.23.a*-1．18，b*11．29，无限光学厚度在2．75mm左右。遮色剂可使Artglass的明度升高，色相偏红黄，这种影响直至修复体厚度为2．50mm时才能不为肉眼察觉。结论：Artglass的色度值在白色背景下随厚度增加而降低，厚度和遮色剂对Artglass的颜色有明显影响。     

前牙冠修复体色差容忍度的初步研究

目的通过研究前牙陶瓷冠修复体的色差容忍度,为提高修复成功率提供有效配色方案。方法选取30名口腔修复科临床患者的单侧上颌中切牙缺损的冠修复体与对侧天然上颌中切牙为实验对象,使用数码相机在标准环境下分别采集单侧天然牙、修复体与天然牙的数码图像,在对图像进行色彩校正后,利用Photoshop识色软件进行色度分析。根据患者和医师对修复体颜色的满意度将修复体分成满意组和不满意组,对2组的色差数据进行Wilcoxon检验。结果颜色满意组修复体与天然牙的总色差△E为2.550 3,颜色不满意组修复体与天然牙的总色差△E为4.077 2,2组总色差的差异具有统计学意义（P＜0.01）。当修复体明度L*、b*、饱和度C*大于天然牙时,颜色满意组与颜色不满意组间△L*、△b*、△C*的差异无统计学意义（P>0.05）;当修复体明度L*、b*、饱和度C*小于天然牙时,颜色满意组与颜色不满意组间△L*、△b*、△C*的差异有统计学意义（P<0.01）。颜色满意组与颜色不满意组间色度差△a*和色相差△H°间的差异均有统计学意义（P<0.05,P<0.01）。结论控制口腔修复体与天然牙间的色差,是配色成功的关键因素;充分利用口腔修复体色差容忍度,将在一定程度上有利于提高修复体的成功率。     

上海地区汉族青年人群恒前牙体部颜色特征临床研究

目的:研究中国上海地区汉族青年人群恒前牙体部颜色特征.方法:132例20-35岁青年志愿者纳入研究,男性49例,女性83例;前牙发育正常,牙体完整,活髓,牙面清洁,无色素沉着、软垢、牙石,无前牙漂白史,使用OLYMPUS Crystaleye电子比色仪进行测量,共获得1584颗上下颌恒前牙体部的颜色参数L*、a*、b*值,按照上下颌中切牙、侧切牙、尖牙不同牙位分组,进行统计分析(t检验和单因素方差分析).结果:青年人群前牙体部色度范围为L*:71.54±4.13,a*:2.11±1.30,b*:19.29±4.02;上颌前牙体部色度范围L*:71.00±3.18,a*:2.33±1.41,b*:20.00±3.81,下颌前牙体部色度范围L*:72.28±3.19,a*:1.89±1.12,b*:18.62±4.00,上下颌前牙体部色差△E为1.93.上中切牙体部色度值参数为L*:73.06±2.60,a*:1.39±1.08,b*:17.71±3.13,下中切牙体部色度值参数为L*:73.14±3.34,a*:1.21±0.87,b*:15.40±2.63;上侧切牙体部色度值参数为L*:70.52±3.29,a*:1.98±0.94,b*:18.97±2.93,下侧切牙体部色度值参数为L*.72.15±3.56,a*:1.64±0.86,b*:17.94±2.76;上尖牙体部色度值参数为L*:69.41±2.42,a*:3.61±1.14,b*:23.28±2.83,下尖牙体部色度值参数为L*:71.58±2.37,a*:71.58±2.37,b*:22.42±2.86.中切牙、侧切牙、尖牙体部色度值之间差异均有统计学意义(P＜0.05).同颌左右同名牙之间差异无统计学意义(P＞0.05),而上下颌同名牙之间差异有统计学意义(P＜0.05).结论:青年人群前牙中中切牙明度最大,其次为侧切牙,尖牙明度最低,色相与彩度则相反,由中切牙至尖牙逐渐增加,颜色渐偏黄、红.比色时应注意前牙列的变化规律和上下颌前牙颜色的差异性.     

CM-700d分光光度计在洁牙喷砂前后前牙色度分析中的应用

目的应用口腔专用的CM-700d分光光度计比较洁牙和喷砂前后前牙色度的变化,为牙齿美容的临床和基础研究提供方法学的参考。方法分别在暗室使用CM-700d分光光度计测量治疗前,洁牙后,喷砂后上下前牙中1/3的L*a*b*值,将洁牙前作为T1组、洁牙后T2组、喷砂后T3组。采用配对t检验分析各组间牙齿色度的差异,再计算其色差值。结果三组的L*、a*、b*值均有统计学差异(P<0.05),且洁牙、喷砂后L*值升高,a*值、b*值降低。T1T2、T1T3的色差为肉眼可察觉,T2T3则相反。结论洁牙、喷砂均能改善外源性着色牙的色度值,洁牙、喷砂后牙齿亮度升高,红绿、黄蓝色品值降低,洁牙后的喷砂能进一步改善牙齿色度,且通过分光光度计分析牙齿色度变化,更具有准确、量化的评判标准。     

烧结次数对金属烤瓷修复体颜色三要素的影响

目的：研究烧结次数对金属烤瓷修复体颜色三要素的影响。方法：采用CIE1976L*a*b*色度系统，计算公式：色差△Eab*={(△L*)^2 (△b*)^2}^1/2，彩度Cab*={(a*)^2 (b*)^2}^1/2，色调角hab*=tg^-1b*/a*,L*代表明度。结果：t检验分析：金瓷烧结5次以上，颜色有明显改变，表现为明度增加；体瓷烧结3次变色，表现为明度增加，彩度增加；遮色瓷绕结3次变色，表现为色调角增大。结论：金属烤瓷修复体烧结5次以上变色，变色表现为明度增加，变色主要与体瓷层明度和彩度的增加有关；遮色瓷层烧结变色对金属烧瓷修复体颜色无明显影响。     

自然老化对SY-1硅橡胶色彩稳定性的影响

目的:了解自然老化对内着色SY-1硅橡胶色彩稳定性的影响,以便为选用适宜的硅橡胶着色颜料提供理论依据。方法:SY-1硅橡胶按所加色料不同分为4组(对照组、水粉颜料土黄色、油画颜料土黄色、无机盐类颜料中铬黄),按国家标准对其进行自然老化同时避光保存并测定老化前后L*、a*、b*值,据此计算DE值。结果:经避光保存6个月,对照组△E为0.78±0.02;水粉土黄组DE为3.95±0.40;油画土黄组DE为2.0±0.12;中铬黄组DE为1.4±0.07。经自然老化6个月,对照组DE为1.32±0.01;水粉土黄组DE为6.69±0.12;油画土黄组DE1.79±0.42;中铬黄组DE为20.14±0.13。结论:SY-1硅橡胶在自然老化条件下,油画类颜料色彩稳定性优于水粉颜料和无机盐类颜料。     

烧结次数对两种钛瓷粉颜色的影响

目的研究牙科钛表面烤瓷烧结次数对钛烤瓷修复体颜色的影响,以指导技工和临床烤瓷操作,同时比较两种瓷粉的颜色在烧结中的稳定性能是否存在差异。方法采用Ti- 22和Vita Titankeramik两种钛瓷粉,设计制作钛瓷标准试件,包括遮色瓷、体瓷和钛- 遮色瓷- 体瓷试件,经1、3、5、7、9次烧结处理,每次烧结后采用ShadeEye NCC比色仪,根据CIE1976L*a*b*色度系统标准测量各样本的L*a*b*值,并计算色差值、彩度和色调角,进行统计分析。结果烧结5次以内,各组试件的L*a*b*值及彩度、明度、色差及色调角均无明显变化,继续烧结后两种瓷粉的L*a*值均发生变化,且有统计学差异（P<0.05）。经过9次烧结,各组试件的色差变化均小于1.5。结论烧结次数在5次以内,钛瓷的颜色无明显变化,继续烧结则出现颜色差异,但肉眼尚未能辨别。     

染色剂对SY-1硅橡胶色彩稳定性影响的研究

目的 测试SY-1硅橡胶在多种外源性染色剂中的颜色稳定性。方法 将SY-1硅橡胶试件浸泡在几种常见的染色试剂中，应用美能达CS-321便携式色差仪分别测试出浸泡前和浸泡后1、2、3、4周的色度值，利用色差公式计算出试件的色差值，并与国外同类产品MDX4—4210进行对照。结果 不同外源性染色剂对硅橡胶有不同的影响。随着染色时间的延长，不同染色剂对硅橡胶的染色程度不同。结论 硅橡胶的色彩稳定性与外源性着色剂的种类，作用时间及自身特性相关。SY-1硅橡胶的色彩稳定性与MDX4—4210基本接近。     

替牙期骨性Ⅲ类错牙合患者颞下颌关节特征的锥形束CT研究

目的:采用锥形束CT(CBCT)研究替牙期骨性Ⅲ类错牙合患者颞下颌关节的影像学特征,探讨Ⅲ类功能状态下,颞下颌关节的生长、改建机制。方法:从就诊于昆明医科大学附属口腔医院正畸科的患者中选取符合纳入标准的替牙期骨性Ⅲ类错牙合患者及骨性Ⅰ类错牙合患者各20名,使用NNT viewer 5.3图像处理软件进行三维重建及线距和角度的测量,并进行统计学分析。结果:替牙期骨性Ⅲ类错牙合患者组和替牙期骨性Ⅰ类错牙合患者组对比结果为:矢状面双侧关节前间隙偏小、双侧关节上间隙偏小、双侧关节结节斜度偏小;冠状面双侧关节内间隙偏小,双侧关节上间隙偏小,双侧关节外间隙偏小,右侧髁状突角度偏小;横截面右侧髁状突前后径偏小。结论:替牙期骨性Ⅲ类错牙合患者颞下颌关节发育不充分,呈现髁状突,关节窝深度,关节结节斜度;冠状面关节内、外间隙均较小的特征。骨性Ⅲ类错牙合患者髁状突在关节窝中处于前置近关节窝顶位置。骨性Ⅲ类错牙合患者颞下颌关节影像学特征与其功能状态相适应。     

柠檬精油对牙周致病菌抑制作用及其安全性初步研究

目的:探讨柠檬精油对牙周致病菌的体外抗菌活性及对细胞增殖的影响。方法:采用微量液体稀释法测定柠檬精油对Pg、Fn、Aa、Pi的最小抑菌浓度(minimal inhibitory concentration,MIC)及最小杀菌浓度(minimum bactericidal concentration,MBC);以较低浓度的MIC为标准稀释LEO作为实验组,采用MTT法测定柠檬精油对HUVECs的毒性作用,明确抑菌浓度下LEO的安全性。结果:柠檬精油对牙周主要致病菌均有抑菌作用,Pg、Fn、Aa、Pi的MIC分别是9.0 g/L、4.5 g/L、4.5 g/L、9.0 g/L,Aa、Fn的 MBC是9.0 g/L,Pg、Pi的MBC未测得。1/2MIC、1/20MIC浓度的LEO能够抑制人脐静脉内皮细胞的生长,而低于1/200MIC浓度的LEO则对人脐静脉内皮细胞的生长没有影响,其中1/200MIC浓度的LEO作用明显优于0.02%的CHX。结论:体外环境中,柠檬精油对牙周致病菌Pg、Fn、Aa、Pi具有抗菌活性,低浓度应用对机体相对安全。     

Clinical and pathological aspects on some odontogenic tumors

Odontogenic tumors constitute a very diverse group of lesions that reflects the complex processes of odontogenesis. Controversies over their classification/subtyping, terminology and diagnosis have been persisted, which has direct bearings on therapeutic and/or prognostic implications.     

Computer-assisted planning for maxillofacial prosthodontic rehabilitation

Computerized tomography (CT) planning and the use of CT derived surgical templates for implant placement have shown promise for restoring function within months after surgical reconstruction of acquired post-oncologic defects.     

Ghlorhexidine as a root canal medicament for treating inflammatory lesions in the periodontal space

Abstract— The purpose of the present study was to investigate the therapeutic effect of intra-canal application of chlorhexidine on inflammatory root resorption. Dental pulps from monkey incisors were infected and resealed prior to extraction of the teeth. Root dentin was mechanically exposed and the teeth were replanted under aseptic conditions. After 4 weeks, the experimental teeth were dressed with chlorhexidine gel and resealed. Animals were sacrificed 4 weeks later, and their jaws prepared for histologic examination. Results showed that both marginal and apical periodontal inflammation and resorption were reduced in the chlorhexidine-treated teeth. It was concluded that the use of intra-canal chlorhexidine may be a useful adjunct in the treatment of inflammatory root resorption, but further human trials need to be undertaken before its clinical use can be recommended.     

Effect of Pingyangmycin on human venous malformation endothelial cells

Purpose: Venous malformations are common vascular anomalies with a propensity of the head and neck. Intralesional injection of Pingyangmycin (PYM, bleomycin A5 hydrochloride) is a widely used sclerotherapy method for the treatment of venous malformation.     

小鼠牙髓干细胞同种异体移植后体内免疫反应初探

目的:初步探究小鼠牙髓干细胞同种异体移植后的全身免疫反应。方法:牙髓干细胞分离获得自C57BL/6 小鼠牙髓组织,培养至第3 代,与纳米羟基磷灰石(n-HA)复合培养形成复合物,扫描电镜观察其生长黏附情况。40只4周龄的C57BL/6 小鼠随机分成两组。实验组将复合物移植入上背部皮下,对照组将纳米羟基磷灰石植入上背部皮下,术后均使用外科方法严密缝合创口。两组动物术后均观察4周、6周处死,分离脾脏,制成脾淋巴细胞悬液,流式细胞仪测定CD4⁺、CD8⁺的值。结果:牙髓干细胞在体外与纳米羟基磷灰石结合良好;免疫组化染色实验组4周、6周均可见牙本质涎蛋白(dentin sialoprotein,DSP)阳性表达;实验组与对照组相比,术后4周、6周CD4⁺/CD8⁺值均无明显差异。结论:牙髓干细胞同种异体移植后,尚不能够引起机体的免疫排斥反应,其在体内仍具有低免疫原性,有望成为组织工程同种异体种子细胞来源。     

Can you be too old for oral implants? An update on ageing and plasticity in the oro‐facial sensorimotor system

This review focuses on the capacity of the brain for plasticity and the utility and efficacy of oral implants in helping to restore oro‐facial sensorimotor functions, especially in elderly patients. The review first outlines the components of the oro‐facial sensorimotor system which encompasses both oro‐facial tissues and a number of brain regions. One such region is the sensorimotor cortex that controls the activity of the numerous oro‐facial skeletal muscles. These muscles are involved in a number of functions including reflexes and the more complex sensorimotor functions of mastication, swallowing and speech. The review outlines the use by the brain of sensory inputs from oro‐facial receptors in order to provide for exquisite sensorimotor control of the activity of the oro‐facial muscles. It highlights the role in this sensorimotor control played by periodontal mechanoreceptors and their sensory inputs to the brain, and how oral implants in concert with the plastic capacity of the brain may, at least in part, compensate for reduced sensorimotor functioning when teeth are lost. It outlines findings of ageing‐related decrements in oro‐facial sensorimotor functions and control. The changes in oro‐facial tissues and the brain that underlie these ageing‐related functional alterations are also considered, along with adaptive and compensatory processes that utilise the brain's capacity for plasticity. The review also notes the evidence t hat rehabilitation that incorporates adjunctive approaches such as sensorimotor training paradigms in addition to oral prostheses such as implants may enhance these processes and help maintain or facilitate recovery of sensorimotor functioning in the elderly.     

Cytokine-induced endogenous procollagenase stored in the extracellular matrix of soft connective tissue results in a burst of collagen breakdown following its activation

Numerous data strongly suggest the involvement of cytokines and the matrix metalloproteinase collagenase (MMP-1) in the pathogenesis of periodontitis. Recently, we have demonstrated that, upon culturing under the influence of IL- lα+EGF, a large amount of inactive procollagenase (MMP-1) is stored in the extracellular matrix of periosteal tissue. We now show that this endogenous reservoir of proenzyme can be operative after activation with plasmin and is able to induce a rapid and almost complete breakdown of the collagenous extracellular matrix. The level of collagen degradation following activation showed a strong correlation with the amount of proenzyme that was incorporated in the tissue. The highest levei of degradation (70% of the total amount of collagenous proteins) was found with the IL-lα+EGF-treated explants, followed by those treated with IL-1α alone (35%). Explants cultured with EGF or in the absence of cytokines, containing only small amounts of procollagenase, showed little collagen breakdown following plasmin activation (7%). Inhibition of metalloproteinases by EDTA, or blockage of plasmin by PMSF, prevented the degradation in all explants irrespective of the amount of proenzyme present in the tissue. Our findings demonstrate that endogenous proenzyme stored in a native connective tissue matrix can be activated at a later time interval which results in a massive breakdown of the tissue. This study shows a possible pathway of collagenase-induced breakdown without recent de novo synthesis of the enzyme. Such a sequence may be operative in chronic inflammatory diseases, such as periodontitis, where production of procollagenase under the influence of cytokines spans a longer time period, whereas breakdown is often characterized by a cyclic behaviour.