不同黏结剂和黏结方法对托槽周围微渗漏的影响

目的：观察、比较不同黏结材料、不同酸蚀方法黏结正畸金属托槽后的微渗漏情况。方法：选择因正畸拔除的健康前磨牙36颗，随机分成3组，每组12颗。A组：37％磷酸酸蚀，京津釉质黏结剂黏结金属托槽；B组：37％磷酸酸蚀．3M Transbond光固化黏结剂黏结；C组：自酸蚀系统＋3M Transbond光固化黏结剂。所有样本进行冷热循环，1％亚甲蓝溶液染色后．立体显微镜下观察并测量各组托槽周围微渗漏情况。用SPSS 11．0统计软件对试验结果先进行方差齐性检验，F检验有统计学意义，进一步用Q检验进行组间比较。结果：①3组间微渗漏差别有统计学意义（F=22．462．P〈0．01），两两比较发现，A组与B组的微渗漏差别无统计学意义（P〉0．05）；而A、B组均较C组的微渗漏小，差别有显著性（P〈0．05）。②3组龈方微渗漏均大于[牙合]方，差别有统计学意义（分别为P〈0．05、P〈0．01、P〈0．01）。结论：①微渗漏的大小与黏结剂的种类无明显关系。②不同酸蚀方法间的微渗漏差别明显，自酸蚀组较磷酸酸蚀组的微渗漏明显大。③同种材料、同种酸蚀方法，托槽龈方微渗漏明显大于[牙合]方。     

EDTA对年轻恒牙釉质粘接强度的影响

目的 研究乙二胺四乙酸二钠（EDTA）对年轻恒牙釉质粘接强度的影响。方法 收集手术拔除的牙根未发育完全的上下颌第三磨牙,共180颗,选取全部离体牙牙冠颊面与牙长轴相对平行的釉质面（倾斜角度小于5°）作为实验粘接面,按实验方法不同随机均分为5组,每组36颗,分别进行以下处理：G0（对照组）：37%磷酸常规酸蚀;G1：37%磷酸+17% EDTA;G2：37%磷酸+10% EDTA;G3：17% EDTA+37%磷酸,G4：10% EDTA+37%磷酸。以上样本均采用GLUMA通用型粘接剂粘接后,行流动树脂堆砌。使用万能材料试验机进行树脂剪切粘接强度的测试。剔除剪切测试中由于树脂块断裂而未形成树脂-釉质面分离的试件,针对剪切粘接强度采用SPSS21.0统计软件进行统计学分析。结果 G0的平均剪切粘接强度（9.80±2.78 MPa）要明显低于G1（11.56±3.30 MPa）、G2（12.01±3.28 MPa）和G4（12.19±3.04 MPa）的剪切粘接强度,其差异都具有统计学意义（P<0.05）。尽管G3的平均剪切粘接强度（10.75±2.85 MPa）要高于G0,但两组之间的强度差异无统计学意义（P=0.261）。此外,G1、G2、G3和G4各组之间的平均剪切粘接强度差异无统计学意义（P>0.05）。结论：酸蚀前、后EDTA去蛋白化处理较单纯酸蚀处理更能增强树脂的剪切粘接强度,但其作用可能会受到EDTA浓度的影响。     

Nd:YAG激光对不同充填材料牙本质边缘微渗漏的影响

目的 评价Nd:YAG激光对不同充填材料与牙本质之间边缘微渗漏的影响。方法 选用人离体前磨牙36颗,制备V类洞,随机分为激光组和对照组,激光组使用80 rnJ、10 Hz脉冲Nd:YAG激光照射后,分别用全酸蚀粘接树脂、自酸蚀粘接树脂和玻璃离子充填洞型,对照组不使用激光,同样用如前所述的3种材料充填洞型。将所有标本浸泡在2%亚甲基蓝溶液中24 h后,用金刚砂片从颊舌向通过充填物中央纵向切开牙体,显微镜下观察龈壁染料渗透的深度。采用SAS8.0软件对数据进行统计学处理。结果 经Nd:YAG激光照射后尽管3种材料与牙本质之间微渗漏程度均有降低趋势,但只有玻璃离子组激光照射后较未照射组微渗漏降低具有统计学意义(P<0.05)。结论 脉冲Nd:YAG激光照射牙本质壁,在一定程度上可能会减少玻璃离子充填材料与洞壁的微渗漏。     

新型通用型牙本质粘接剂修复Ⅴ类洞微渗漏疗效研究

目的    评价一种新型通用型牙本质粘接剂All Bond Universal对Ⅴ类洞边缘的封闭效果。方法    120颗新拔除的正常双尖牙随机分为4组（30例）,分别在颊舌侧颈缘上1 mm处制备标准的Ⅴ类洞（2 mm × 2 mm × 2 mm）,分别用新型通用型粘接剂All Bond Universal（全酸蚀和自酸蚀两种方法）、全酸蚀粘接剂Prime& Bond NT和自酸蚀结剂G Bond进行粘接和样本制备,经50 %氨化硝酸银染色后,体式显微镜下观察边缘微渗漏的染色情况,记录评分结果,数据用SPSS 20.0软件包进行统计学分析。结果    3种粘接剂均存在微渗漏现象,使用All Bond Universal的微渗漏评分低于同种使用方法的其他两组（P＜0.05）,All Bond Universal两种使用方法的微渗漏评分差异无统计学意义（P＞0.05）,龈方微渗漏评分整体高于牙合方（P＜0.05）。结论    新型通用型牙本质粘接剂All Bond Universal是一种临床应用方便、有效的牙本质粘接剂,全酸蚀和自酸蚀两种方法对边缘微渗漏的影响无差异,但其远期效果须进一步实验研究。     

西帕依固龈液联合米诺环素对局限型侵袭性牙周炎牙周致病菌的作用分析

目的 评价西帕依固龈液和米诺环素联合用药对局限型侵袭性牙周炎患者唾液中伴放线杆菌（A.a）、牙龈卟啉单胞菌（P.g）和中间普氏菌（P.i）检出率和相对含量的影响。方法 90例局限型侵袭性牙周炎患者随机分为西帕依固龈液组、米诺环素组及联合用药组3组,每组30例。治疗前1周和治疗后1个月分别采集研究对象唾液,进行DNA提取及PCR反应,分析患者唾液中A.a、P.g和P.i的检出率和相对含量。结果 3组用药后A.a、P.g和P.i检出率与用药前差异无统计学意义（P>0.05）,但相对含量有所降低,差异有统计学意义（P<0.05）;与米诺环素组相比,西帕依固龈液组P.i的相对含量更低（P<0.05）;与米诺环素组和西帕依固龈液组相比,联合用药组A.a、P.g、P.i的相对含量更低（P<0.05）。结论 西帕依固龈液和米诺环素联合用药对牙周炎患者唾液中A.a、P.g和P.i检出率的影响甚微,但能抑制其相对含量,联合用药比单独用药的抑制效果好。     

不同牙龈生物型在牙冠延长术后牙周稳定性的评价

目的 评价不同牙龈生物型在牙冠延长术后牙周的稳定性。方法 选取需行前牙牙冠延长术的30例患者共128颗患牙,分为薄龈生物组（n=52）和厚龈生物组（n=76）,牙周基础治疗后行牙冠延长术,检测术前、术后2周、术后1、3、6个月两组患者牙龈缘位置,牙周探诊深度（PD）以及龈沟出血指数（SBI）并进行分析。结果 两组术后PD和SBI较术前均有明显改善（P<0.05）,手术前后两组之间的PD和SBI均无明显差异（P>0.05）,术后3个月薄龈生物型龈缘位置已基本稳定,术后6个月厚龈生物型组龈缘冠向移位更明显。结论 冠延手术后,厚龈生物型需要更长的恢复期稳定龈缘位置,修复体的制作应在术后6个月以后进行。     

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目的评价4种黏结剂对氧化锆全瓷嵌体边缘微渗漏的影响。方法选取2012年8月佛山市禅城区向阳医院口腔科新鲜拔除的上颌第三磨牙40颗,随机分为A、B、C、D组,每组10颗,制备V类洞形。4组离体牙分别采用全酸蚀黏结剂AdperSinglebond2（A组）及自酸蚀黏结荆ClearFilSEBond（B组）、MultilinkSpnnt（C组）和AdperEasyOne（D组）黏结氧化锆全瓷嵌体,修复后离体牙经冷热循环后行2％亚甲基蓝染色,根管显微镜下观察各组微渗漏程度并进行比较。结果在铪壁,c组微渗漏明显高于A和B组,差异均有统计学意义（P〈0．05）;但与D组差异无统计学意义（P〉0．05）。在龈壁,c组微渗漏明显高于其他3组,差异均有统计学意义（P〈0．05）;而其他3组之间差异均无统计学意义（P〉0．05）。结论自酸蚀黏结剂ClearFilSEBond和AdperEasyOne的封闭能力较好,且较全酸蚀黏结剂操作简单方便,推荐临床使用。     

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.     

固位形和酸蚀在瓷化树脂修复楔状缺损中的作用

目的研究固位形和酸蚀在瓷化树脂修复楔状缺损中的作用。方法选择楔状缺损患者98例294颗患牙,随机分为4组：A组75颗,制备固位形不酸蚀;B组74颗,不制备固位形不酸蚀;C组73颗,制备固位形进行酸蚀;D组72颗,不制备固位形进行酸蚀。瓷化树脂修复楔状缺损,随访观察2年。结果4组患牙的牙髓不良反应、边缘密合性等无明显差异。无论酸蚀与否,有固位形的成功率明显高于无固位形的（P〈0.05）,酸蚀处理对成功率没有显著影响（P〉0.05）。结论瓷化树脂修复楔状缺损时,制备固位形有助于提高成功率。     

超声冲洗锉引起牙本质界面微裂的初探

目的 观察超声冲洗锉作用于牙本质界面引起微裂的情况。方法 收集牙体完整的离体牙制作80片牙本质磨片,光镜下观察比较15#冲洗锉尖分别在不同功率（功率5档和10档）以及不同工作时间（30s、1min、2min和3min）所产生的牙本质微裂的情况。结果 在相同功率下,不同工作时间的超声荡洗引起的牙本质微裂差异无统计学意义（P > 0.05）。在相同工作时间下,不同功率的超声荡洗引起的牙本质微裂的差异没有统计学意义（P > 0.05）。结论 在使用冲洗锉行超声荡洗与牙本质面接触时有产生微裂的可能,在3min内、功率10以下超声荡洗的功率大小与工作时间对牙本质界面微裂程度无明显差异。     

Effect of Resin Coating and Chlorhexidine on the Microleakage of Two Resin Cements after Storage

Purpose: This study evaluated the effect of resin coating and chlorhexidine (CH) on microleakage of two resin cements (Panavia F2.0, Nexus 2) after water storage. Materials and Methods: Class V cavities were prepared on the facial and lingual surfaces of 120 intact human molars with gingival margins placed 1 mm below the cementoenamel junction. Indirect composite inlays were fabricated. The specimens were randomly assigned into six groups (n = 40). Indirect composite inlays (Gradia) were cemented as follows: Group 1 (control): inlays were cemented with Panavia F2.0 according to the manufacturer's instructions. Group 2: the ED‐primed (ED Primer, Kuraray Dental, Tokyo, Japan) dentin was coated with a resin layer before cementation of the inlays with Panavia F2.0. Group 3: a 2% CH solution was applied before bonding with Panavia F2.0. Group 4: after CH application, the primed dentin was coated with a resin layer before cementation with Panavia F2.0. Group 5: (control) after applying Optibond Solo Plus, the inlays were cemented with Nexus 2. Group 6: after etching, CH was applied, and cementation was performed similarly to group 5. Half the specimens in each group were stored in distilled water for 24 hours, while the other half were stored in distilled water for 6 months. After storage, the teeth were placed in 1% methylene blue dye for 24 hours, sectioned, and evaluated under a 20× stereomicroscope. Dye penetration was scored using 0 to 3 criteria. Data were analyzed using nonparametric tests. Results : Resin coating of ED primer for Panavia F2.0 significantly reduced microleakage at the gingival margins after 6 months (p < 0.05). CH application in Panavia F2.0 did not lead to a significant difference in the microleakage at both margins, after 24 hours and 6 months (p > 0.05). The application of CH showed significantly less microleakage than that of the control group at the gingival margins of Nexus 2 after 6 months. In general, gingival margins showed more microleakage than occlusal margins. Conclusion: An additional resin layer applied to a self‐etch cement can improve long‐term dentinal sealing for indirect restorations, while CH cannot; however, CH reduces gingival microleakage in an etch‐and‐rinse cement after aging.     

Dentine bond strength and microleakage of flowable composite,compomer and glass ionomer cement

Background: To assess in vitro the dentine bond strength and microleakage of three Class V restorations viz. flowable composite, compomer and glass ionomer cement. Methods: Eighteen dentine specimens were prepared and randomly distributed among three groups. Three kinds of restoration materials were each bonded on prepared dentine surfaces in three groups as per the manufacturers’ instructions. Group Aelite: Tyrian SPE (a no‐rinse, self‐priming etchant) + One Step Plus (an universal dental adhesive) + Aeliteflo (a flowable composite); Group Dyract: Prime & Bond NT (a no‐rinse, self‐priming dental adhesive) + Dyract AP (a compomer); Group GlasIonomer: GlasIonomer Type II (a self‐cured restorative glass ionomer). Fifteen dentine/restoration microtensile bond test specimens were prepared from each group and were subjected to microtensile bond strength testing. The bond interfaces were observed morphologically using a scanning electron microscope (SEM). Twenty‐four cervical cavities of 4.0 mm mesiodistal length, 2.0 mm occlusogingival height and 1.5 mm depth were prepared at the cemento‐enamel junction (CEJ) on both buccal and lingual surfaces of each tooth. The cavities were each filled with flowable composite (Group Aelite), compomer (Group Dyract) and glass ionomer cement (Group GlasIonomer) using the same material and methods as for the microtensile bond tests. Microleakage of each restoration was evaluated by the ratio of the length of methylene blue penetration along the tooth‐restoration interface and the total length of the dentine cavity wall on the cut surface. Results: One‐way ANOVA and least significant difference (LSD) tests revealed statistically significant differences among the dentine bond strength for Group Aelite (28.4 MPa), Group Dyract (15.1 MPa) and Group GlasIonomer (2.5 MPa). SEM images showed intimate adaptation in the restoration/dentine interfaces of Group Aelite and Group Dyract. All of the systems tested in this study presented microleakage. However, both Group Aelite (0.808) and Group Dyract (0.863) had significantly less microleakage than Group GlasIonomer (0.964). There were no statistically significant microleakage differences between Group Aelite and Group Dyract, and no statistically significant microleakage differences between the occlusal margin and gingival margin. Conclusions: None of the systems tested in this study completely eliminated microleakage. However, both the flowable composite and compomer provided stronger dentine bond strengths and better margin sealing than the conventional glass ionomer cement. Occlusal forces exerted the same effects on microleakage of the occlusal margin and gingival margin in cervical cavities.     

The effect of LED curing mode on microleakage of Class V cavity restored by silorane-based composite

Abstract

Objective. This in vitro study evaluated the effect of soft-start curing mode by LED unit on the marginal microleakage of silorane composite restoration. Materials and methods. Class V cavities were prepared on the buccal surfaces of 80 extracted molars at the cementoenamel junction and randomly divided into eight groups. In groups 1–4, four adhesive/composite combinations (silorane/silorane, silorane/Z250, Adper Single Bond/Z250, Clearfil SE Bond/Clearfil AP-X) were applied and the composites were cured under standard mode at 1500 mW/cm² for 20 s. In the other four groups, after applying the same adhesive/composite combinations, the composites were cured at 550 mW/cm² for 10 s followed at 1500 mW/cm² for 15 s. After 24 h of water storage and thermocycling, the specimens were placed in 1% methylene blue solution. The dye penetration was assessed under a stereomicroscope. The data were analysed using non-parametric tests. Results. There were no significant differences among four groups for two curing modes at the occlusal and gingival margins (p > 0.05). The soft-start curing had a positive effect on the gingival marginal sealing of group 1 (p < 0.05), but not for the other three groups (p > 0.05). Conclusion. The beneficial effect of relatively high soft-start curing on marginal sealing of Class V restoration depends on a combination of the adhesive and composite types, having a positive effect on silorane adhesive/silorane-based composite at the gingival margin.     

3种复合树脂充填Ⅴ类洞的微渗漏比较研究

目的:比较义获嘉N Ceram纳米瓷化树脂、N Flow流动树脂及Bulk Fill 三次方大块充填树脂充填上颌前磨牙Ⅴ类洞后树脂充填体边缘的微渗漏情况,评估3种不同复合树脂的抗微渗漏性能,寻找较好的充填V类洞的复合树脂材料.方法:选取牙体完整、健康的人离体前磨牙66颗,随机分为3组(n=22).所有样本牙在颊侧颈部制备标准V类箱状洞型(长4 mm、宽3 mm、深2 mm).3组试验牙经选择性釉质酸蚀自黏结后,分别使用N Ceram纳米瓷化树脂(A组)、N Flow流动树脂(B组)及Bulk Fill三次方大块充填树脂(C组)进行充填.充填完成后,3组试验牙均行弱光启动固化,打磨抛光.将3组样本进行1500个周期的冷热循环,2％亚甲基蓝浸泡染色7d,然后沿牙体颊舌向切片.每组随机选取2颗样本牙,在扫描电镜下观察牙体-充填体交界面的密合程度;其余60颗样本牙在体视显微镜下(×40)观察剖面充填体的微渗漏情况.采用Spot Advanced软件测量微渗漏深度,并根据0～3分分别给(牙合)、龈壁微渗漏程度评分.采用SPSS17.0软件包对各组的微渗漏深度分别进行Kruskal-Wallis秩和检验和Mann-Whitney检验.结果:义获嘉Bulk Fill组树脂在3组中龈壁的微渗漏最小,且与另外2组相比有显著差异,N Ceran纳米树脂组与N Flow流动树脂组龈壁的微渗漏均较高(P＜0.05);3组复合树脂材料(牙合)壁的微渗漏无显著差异(P＞0.05);3组树脂(牙合)壁的微渗漏值均比龈壁小且差异显著(P＜0.05).结论:3组树脂在(牙合)壁的微渗漏值无显著差异.义获嘉Bulk Fill组树脂充填V类洞时.在3组中龈壁的微渗漏最小,且与另外2种树脂之间有显著差异.     

Marginal adaptation and microleakage of a bulk-fill composite resin photopolymerized with different techniques

The purpose of this study was to investigate the marginal adaptation and microleakage of SonicFill composite with different photopolymerization techniques. Class II cavities were prepared in 40 premolars and divided into groups according to the photopolymerization technique (n = 10): G1:1200 mW/cm² for 20 s; G2:1200 mW/cm² for 40 s; G3:Soft-start with 650 mW/cm² for 5 s and 1200 mW/cm² for 15 s; G4:Soft-start with 650 mW/cm² for 10 s and 1200 mW/cm² for 30 s. The cavities were restored with OptiBond FL adhesive and SonicFill. Epoxy resin replicas were obtained before and after thermocycling. The occlusal and cervical margins were analyzed with scanning electron microcopy and expressed as the percentage of continuous margins (%CM). The specimens were submitted to microleakage with silver nitrate. ANOVA and Tukey’s test revealed that the %CM at the linguo-occlusal margin for group 1 (83.19%) was significantly different from groups 2, 3 and 4, which had values over 95%. At the cervical margin, there was no statistically significant difference between the groups. After thermocycling, there was a significant decrease in %CM. The predominant score of microleakage was 1 in enamel and 3 in dentin. The SonicFill composite led to gap formation and microleakage, especially in the dentin at the cervical margin, regardless of the photopolymerization technique employed.     

Effect of different monomer-based composites and acid etching pre-treatment of enamel on the microleakage using self-etch adhesives systems

Objective. To evaluate quantitatively the marginal microleakage of restorations carried out with self-etching adhesives with or without prior phosphoric enamel acid etching of silorane or methacrylate resin-based composite restorations subjected to thermal cycling. Materials and methods. Forty cavities were prepared at the proximal surface of bovine incisors and randomly divided according to the etching of the enamel and restorative system used. The groups were restored with methacrylate [Adper SE Plus adhesive (3M ESPE) + Filtek Z250 (3M ESPE)] or silorane [Filtek LS adhesive (3M ESPE) + Filtek LS composite (3M ESPE)] restorative systems, light-cured using a LED unit (Bluephase 16i, Vivadent). After restorative procedure and thermocycling (1000 cycles), the specimens were immersed in methylene blue for 2 h. The specimens were triturated and the powder was used for analysis in an absorbance spectrophotometer. Data were statistically analyzed by 2-way ANOVA (alpha = 0.05). Results. No statistical difference between the restorative materials tested with or without previous acid etching of enamel in Class II marginal microleakage was observed (p > 0.05). Conclusions. The use of acid etching prior to self-etching adhesives did not interfere on the microleakage of methacrylate- or silorane-based restorations.     

Microleakage of composite restorations after acid or Er-YAG laser cavity treatments.

OBJECTIVES: The purpose of this study was to compare microleakage of Class V restorations following acid, laser or laser and acid treatment of cavity walls. METHODS: Standardized lingual and buccal Class V preparations were made in 18 human extracted third molars. The preparations were randomly assigned to three equal groups (n=12). Group 1: cavities were treated with 35% phosphoric acid. Group 2: cavities were irradiated with an Er-YAG laser at 2Hz and 250mJ on dentin and 300mJ on enamel, with water cooling. Group 3: cavities were irradiated with the laser before acid etching. Scotchbond 1 Adhesive System and Z100 resin composite were used for restorations. The specimens were stored in water for 24h at 37 degrees C and thermally cycled (500x) between 6-60 degrees C. After 24h immersion in 0.5% basic fuchsin, dye penetration was recorded according to an ordinal scale. Data were analysed using non-parametric statistical tests (Kruskal-Wallis and Mann-Whitney). RESULTS: On the occlusal walls, microleakage in acid etched cavities was significantly lower than that achieved after laser treatment (P<0.001) or after both treatments (P<0.05). On the gingival walls, no statistical differences were found. SIGNIFICANCE: Laser irradiation of enamel is not a valid alternative to acid-etching pretreatment for resin composite materials adhesion. Acid etching alone gave the lowest microleakage at the occlusal margin. No differences were found for microleakage on gingival wall, although lased dentin surfaces presented several characteristics that appear to be advantageous for bonding.     

Effect of Aging on Coronal Microleakage in Access Cavities through Metal Ceramic Crowns Restored with Resin Composites

Purpose: The purpose of this in vitro study was to determine if packable resin composite with/without flowable resin composite has the ability to prevent coronal leakage in restored endodontic access openings following aging. Materials and Methods: Eighty simulated standardized access cavities of metal‐ceramic crowns were fabricated and fixed on Vitrebond cavities filled with an epoxy resin. The specimens were randomly divided into two main groups: (1) Group A—Access cavities filled with only packable composite (Filtek P60); (2) Group B—Access cavities filled with Filtek P60 and a flowable composite (Filtek Z350) as liner. Each main group was further subdivided randomly into four subgroups according to water storage and thermocycling periods. All specimens were immersed in blue ink solution for 24 hours and then sectioned into quadrants. The extension of blue ink along the metal‐ceramic crown/composite resin interface was measured linearly using image analyzer and then analyzed by three‐way ANOVA and independent t‐test with a Mann‐Whitney test. The level of significance was set at p < 0.05. Results: All tested subgroups demonstrated different levels of microleakage. There was no significant difference related to restorative technique; however, there was a significant difference related to water storage and thermocycling. Conclusions: All tested techniques and materials in this study showed microleakage. Packable composite while a flowable liner showed a marginally better result than packable composite alone. Excessive thermocycling resulted in significant differences among the test groups.     

Microleakage of different resin composite types.

OBJECTIVE: The purpose of this study was to evaluate the microleakage of Class V cavity preparations restored with three different types of resin composite and an ormocer. METHOD AND MATERIALS: Forty Class V cavities were prepared in buccal and lingual surfaces of 20 recently extracted molar teeth. The occlusal margin of each restoration was on enamel and the gingival margin on dentin. Teeth were randomly assigned to four groups of 5 teeth each and restored as follows: Group I, flowable resin composite (Tetric Flow); Group II, hybrid resin composite (Z100); Group III, packable resin composite (Solitaire 2); Group IV, organically modified ceramics-ormocer (Admira). In all groups, the manufacturers' instructions were strictly followed. All restorative resin composite materials were placed in one increment. All teeth were then immersed in 0.5% basic fuchsin solution for 24 hours after thermocycling (200 cycles; between 4 degrees C to 60 degrees C). The teeth then were longitudinally sectioned and observed under a stereomicroscope. The degree of dye penetration was recorded and analyzed with the Kruskal-Wallis and Mann-Whitney tests. RESULTS: No statistically significant differences in microleakage were observed between groups either on enamel or dentin. CONCLUSION: All restorative materials demonstrated equal effectiveness in reducing microleakage.     

冷光漂白对树脂-牙釉质微拉伸强度及边缘微渗漏的影响

目的：探讨冷光漂白对树脂-牙釉质微拉伸强度、界面微观形态及V类洞边缘微渗漏的影响。方法：30颗离体前磨牙随机分为5组,每组6颗牙。P组：未漂白;P0组：漂白后即刻;P1组：漂白后储存于人工唾液1周;P2组：漂白后储存于人工唾液2周;P3组：漂白后储存于人工唾液3周。各组Z-350树脂修复,进行微拉伸实验及扫描电镜观察。另30颗离体磨牙进行V类洞微渗漏实验,分组同上,每组6颗牙,定为S、S0、S1、S2、S3组。SPSS13.0软件包进行统计学处理。结果：P、P2、P3组微拉伸强度显著高于P0组（P〈0.05）,P2、P3组微拉伸强度显著高于P1组（P〈0.05）,其余各组均无显著差异。扫描电镜观察树脂-釉质界面,P0组存在缝隙,P1、P2、P3组界面逐渐致密。S、S2、S3组牙合壁微渗漏值显著低于S0组（P〈0.05）,各组龈壁微渗漏无显著差异。组内比较：除S组外,其余4组龈壁微渗漏均显著大于牙合壁（P〈0.05）。结论：冷光漂白后不适合进行即刻树脂修复,树脂修复最佳时间是漂白后2周。