两种后牙树脂充填窝洞的边缘微渗漏观察

目的：观察并比较3MP90和P60两种后牙树脂与3M第七代自酸蚀粘接剂联合使用充填窝洞的边缘微渗漏情况。方法：40颗健康离体后牙随机分为A、B、C、D 4组,颊面正中制备5 mm×3 mm×2 mm的箱状洞型。其中A、B组用P90,C、D组用P60树脂分层充填;A、C组用Adper EasyTM one,B、D组用Single bond 2。标本经温度循环后,1%亚甲基蓝溶液染色48 h,显微镜下观察每颗牙3个剖面（近中、远中及正中）6个位点的染料渗入深度,采用计量资料两样本均数比较的t检验进行统计学分析。结果：A组与C组,B组与D组之间微渗漏有统计学差异（P〈0.05）;A组与B组,C组与D组之间微渗漏无统计学差异。结论：P90树脂的边缘封闭性优于P60。     

不同洞深和固化后不同时间对通用型复合树脂微渗漏的影响

目的观察3种通用混合型复合树脂充填后,不同洞深和固化后不同时间对界面微渗漏的影响。方法取离体前磨牙和磨牙各75个,分别在颌面中央制备直径2mva,洞深2mm（前磨牙）和直径2mm,洞深3mm（磨牙）的Ⅰ类洞．用随机数字法将两种洞深的样本各分别分为3组,分别用Chalisvaa复合树脂、Spectrum TPH光固化树脂、Esthet—X复合树脂充填,于光照固化后10min、30min、1h、24h和48h,各时间点分别随机抽取各组5个样本．通过充填体矢状方向切开。50％避光氨化硝酸银液浸泡显影,体视显微镜下用测微软件测量粘结界面微裂隙。结果3种通用型复合树脂充填不同洞深均出现微裂隙．固化30mint24h裂隙最大,随着洞深深度增加。微裂隙减小;不同时间微裂隙变化速度不同。结论固化30min～24h充填物脱落的可能性最大,建议固化后10min内隔湿．24h患侧保护性忌咀嚼;分层添加技术适用于较深的窝洞。     

Er：YAG激光预备及酸蚀处理对复合树脂充填体微渗漏的影响

目的 研究Er∶YAG激光备洞及酸蚀处理对复合树脂充填体微渗漏的影响.方法 将40颗离体前磨牙随机平均分为5组制备洞型：A组,高速牙钻预备加酸蚀;B组,Er∶YAG激光预备;C组,Er∶YAG激光预备加酸蚀;D组,高速牙钻预备加Er∶YAG激光蚀刻;E组,高速牙钻预备加Er∶YAG激光蚀刻后酸蚀.所有样本经复合树脂充填后交替放置于5℃与55℃水中各1 min,间隔45 s,共2000个周期进行冷热循环,然后用0.2％亚甲基蓝染色后颊舌向劈开,体视显微镜下观察剖面,记录其微渗漏情况,并进行统计学分析.另选6颗离体前磨牙,随机分为3组,按上述A、B、C三组方法制备,扫描电镜下观察其牙本质界面的结构.结果 在（牙合）壁与龈壁,B组染料渗入严重,到达洞底,微渗漏最大,与其他各组相比有统计学差异（P＜0.05）,A、C、D、E组染料渗入表浅,微渗漏程度之间没有统计学差异（P＞0.05）.扫描电镜下,A组牙本质表面较平整,无玷污层存在,牙本质小管口开放.B组牙本质表面不平整如鳞片状,无玷污层,牙本质小管口开放,直径小于酸蚀组.C组牙本质小管口开放,无玷污层存在,管周牙本质脱矿明显.结论 单纯Er∶YAG激光预备比传统牙钻制备结合酸蚀处理洞型更易发生微渗漏,若Er∶YAG激光预备结合酸蚀剂处理可以使微渗漏程度减小,Er∶YAG激光蚀刻可以达到和酸蚀剂类似的效果.     

生物活性玻璃预处理对牙本质粘接界面耐久性的影响

目的:研究生物活性玻璃(bioactive glass, BG)预处理对维持牙本质粘接界面耐久性的作用。方法:选取30颗无龋坏第三磨牙,去除冠部釉质制备牙本质平面,随机均分对照组、BG组、三偏磷酸钠(sodium trimetaphosphate, STMP)-聚丙烯酸(polyacrylic acid, PAA)-BG组(S-P-BG组)。各组均使用35%(质量分数)磷酸酸蚀牙本质样本,BG组再使用0.5 g/L BG涂擦酸蚀后的牙本质样本;S-P-BG组先使用5%(质量分数)STMP、5%(质量分数)PAA浸泡酸蚀后的牙本质样本1 min,再使用0.5 g/L BG涂擦牙本质样本。各组样本使用3M Single Bond 2粘接剂及3M Z350XT复合树脂粘接,并制备微拉伸柱状样本,每颗牙的柱状样本按时间随机分为24 h、1个月、3个月组。各组样本保存在37 ℃人工唾液(artificial saliva, AS)中相应时间后,进行微拉伸粘接强度测试,并使用单因素方差分析及LSD法进行统计学分析,扫描电镜下观察粘接断裂界面形貌。另选取27颗无龋坏第三磨牙制备牙本质平面,随机分为对照组、BG组、S-P-BG组,并按上述分组处理牙本质样本,再使用含0.1%(质量分数)罗丹明B的3M Single Bond 2粘接剂完成粘接。去除样本牙根暴露髓腔,并保存在 37 ℃ AS中24 h、1个月、3个月后,髓腔内放置0.1(质量分数)荧光素钠溶液染色1 h,激光共聚焦显微镜观察粘接界面形态及混合层微渗漏。结果:AS中浸泡24 h、1个月后,3组微拉伸粘接强度间的差异无统计学意义(P>0.05);浸泡3个月后,S-P-BG组微拉伸粘接强度为(36.91±7.07) MPa,高于对照组粘接强度(32.73±8.06) MPa,且差异有统计学意义(P=0.026);对照组、BG组3个月的微拉伸粘接强度较24 h呈下降趋势,且差异有统计学意义(对照组P=0.017,BG组P=0.01);S-P-BG组3个月微拉伸粘接强度较24 h粘接强度[(37.99±7.98) MPa]下降,但差异无统计学意义(P>0.05)。扫描电镜观察24 h粘接断裂面,3组均未见明显矿化;1个月、3个月后,BG组、S-P-BG组的粘接界面可见矿物质形成,S-P-BG组无明显胶原暴露。激光共聚焦显微镜观察对照组、BG组与S-P-BG组树脂突形成的形态及数量无明显差异;3组样本粘接24 h后粘接界面混合层均有渗漏,3个月后对照组微渗漏增加,BG组和S-P-BG组混合层微渗漏减少。结论:BG预处理牙本质粘接界面能够在粘接界面形成矿物质,减少粘接混合层微渗漏;STMP、PAA 与BG共同预处理牙本质粘接界面,可能在一定程度上维持牙本质粘接修复的耐久性。     

INFLUENCE OF THERMAL STRESS ON MARGINAL INTEGRITY OF RESTORATIVE MATERIALS

The aim of this study was to evaluate the influence of thermal stress on the marginal integrity of restorative materials with different adhesive and thermal properties. Three hundred and sixty Class V cavities were prepared in buccal and lingual surfaces of 180 bovine incisors. Cervical and incisal walls were located in dentin and enamel, respectively. Specimens were restored with resin composite (RC); glass ionomer (GI) or amalgam (AM), and randomly assigned to 18 groups (n=20) according to the material, number of cycles (500 or 1,000 cycles) and dwell time (30 s or 60 s). Dry and wet specimens served as controls Specimens were immersed in 1% basic fuchsine solution (24 h), sectioned, and microleakage was evaluated under x40 magnification. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests: Thermal cycling regimens increased leakage in all AM restorations (p<0.05) and its effect on RC and GI restorations was only significant when a 60-s dwell time was used (p<0.05). Marginal integrity was more affected in AM restorations under thermal cycling stress, whereas RC and GI ionomer restoration margins were only significantly affected only under longer dwell times.     

自酸蚀粘接剂与纳米全酸蚀粘接剂对充填体边缘微渗漏的影响

目的:比较光固化树脂用自酸蚀粘接剂ONE-UP BOND F(俗称"变色龙")与3M纳米全酸蚀粘接剂Adper Single Bond2对充填体边缘的封闭情况。方法:取新鲜离体双尖牙40颗,在颌面各制备3mm×2mm×2mm箱状洞型,随机分成两组,A组使用ONE-UP BOND F粘接剂,B组使用3M ESPE Adper Single Bond2全酸蚀粘接剂,3Mp60后牙专用复合树脂充填,0.5%碱性品红溶液中染色24h后,将充填体近远中剖开,在立体显微镜下观察充填体边缘的染色情况。结果:两种粘接剂均有微渗漏现象发生,光固化树脂用自酸蚀粘接剂ONE-UP BOND F的边缘微渗漏情况略优于3M纳米全酸蚀粘接剂Adper Single Bond2,但差异无统计学意义(P>0.05)。结论:虽然两种粘接剂都不能消除充填体边缘的微渗漏,但ONE-UP BOND F自酸蚀粘接剂效果略好,而且操作简单,适合临床推广。     

Microleakage and sealant penetration in contaminated carious fissures

Objectives

The aim of the present in vitro study was to evaluate the effect of an adhesive system on microleakage and sealant penetration depth in carious fissures after different surface contamination circumstances.

Methods

Extracted third molars (n = 128) with small occlusal cavitated carious lesions were randomly divided into eight experimental groups and sealed under four different surface conditions. 1, Dry conditions; 2, water contamination; 3, saliva contamination; 4, saliva contamination and air-drying. Two sealant protocols were applied, one using a fissure sealant (Teethmate F) and one using an additional adhesive system (SA primer and Photo Bond). The control group consisted of sound third molars (n = 16), that were sealed under dry conditions. After thermocycling (n = 500 cycles), teeth were immersed in 1% methylene blue for 24 h, sectioned and digitally photographed. Microleakage was evaluated on a three-point rating scale and analysed using a Chi-square test. Additionally, the presence of caries and incomplete sealant penetration was scored from photographs and analysed using logistic regression.

Results

A statistical significant difference regarding microleakage scores was present between sealed carious and sealed sound fissures. The use of an adhesive system in case of water contamination significantly reduced microleakage (p < 0.05). With regard to sealant penetration depth, there were significant differences present for carious sealed fissures, use of an adhesive system prior to sealing, and water and saliva contamination.

Conclusions

Use of an adhesive system improved the effectiveness of sealants placed after water contamination in carious fissures. However, sound fissures showed less microleakage and better penetration abilities than carious fissures.     

(纸尖法定量研究镓合金的倒封闭性能

目的 研究根尖倒封闭材料镓合金的密封性能。方法 将标准纸尖法和染料渗法相结合定量分析７８颗完整离休平时管牙根尖倒一的微渗漏情况。结果 镓合金组根尖充填二２８天时的微渗情况明显 地ＧＫ高铜银汞合金组,差异显著性意义（Ｐ〈０．０１）。结论 镓合金ＧＫ高铜银汞合金具有更好的根尖倒封闭性能。     

碘仿自固化磷酸钙根管糊剂封闭性的体外研究

目的:观察注射型碘仿自固化磷酸钙(CPC)根管糊剂在体外充填根管的封闭性能。方法:62颗离体单根管牙用K锉常规法预备至40#,其中58颗随机分为2个实验组,分别用注射型碘仿CPC糊剂和氧化锌丁香油碘仿糊剂作为根管封闭剂,牙胶尖侧压法充填根管。另外4颗作为对照组。根充材料凝固后,将牙的根尖部分浸泡于2%亚甲蓝染料中6d,沿牙体长轴纵向劈开,测量根管内壁染料渗漏长度。采用团体t检验进行统计学分析。结果:注射型碘仿CPC充填组平均渗漏8.400mm,氧化锌丁香油碘仿糊剂组平均渗漏5.300mm,2组的渗漏值有显著性差异(P<0.05)。结论:碘仿CPC的体外根管封闭性不及氧化锌丁香油碘仿糊剂。