酸蚀时问对牙本质粘结界面纳米渗漏的影响

目的:观察、比较不同酸蚀时间对4种全酸蚀粘结剂(OptiBond Solo(0B)、Single Bond(SB)、One-Step(OS)、Prime&Bond NT(PB))牙本质粘结界面纳米渗漏的影响.方法:选取64颗无龋坏人磨牙,用600目碳化硅砂纸在流水冲洗下预备出统一的牙本质粘结面玷污层,分别选用4种粘结剂在不同粘结面酸蚀时间条件下进行粘结处理;每颗牙齿垂直于粘结面切割出4个4mm×0.9mm×4mm粘结试件,分别在TEM下观察、比较其粘结界面纳米渗漏.结果:4种粘结剂的牙本质粘结界面纳米渗漏均随酸蚀时间的延长而增加.结论:延长酸蚀时间,在牙本质粘结界面中遗留有更多的未封闭结构,加速牙本质粘结界面老化.     

不同酸蚀体系、时间和粘结剂对牙本质粘结界面纳米渗漏影响的实验研究

目的 以离体前磨牙为研究对象,运用扫描电镜观察不同酸蚀体系、粘结剂和时间对牙本质粘结界面纳米渗漏的影响,评价粘结剂边缘封闭性,以期寻找合适的酸蚀时间与方法,为临床使用提供实验依据.方法 将45颗离体前磨牙,分别用320、400及600目碳化硅砂纸在流水冲洗下预备出牙本质粘结面玷污层.随机分为5组,除E组5颗外,A、B、C及D组每组10颗牙,分别酸蚀0、15、30及45 s后再分别使用SB和PB粘结剂处理每个亚组5颗牙;E组:使用AP粘结剂;制件,银染后制作电镜标本,SEM下观察并照相.结果 ①SEM观察:A组中未见银染颗粒,未见纳米渗漏;其余组均可见银的积聚,呈线状或点状,纳米渗漏程度不一,B组与E组最少,D组SB亚组最多.②NIH Image数据分析:A组为零;B组的SB与PB亚组纳米渗漏差异无统计学意义(P>0.05);C组和D中SB亚组产生的纳米及渗漏比PB亚组产生的纳米渗漏大,差异具有统计学意义(P<0.05).SB和PB在不同酸蚀时间下(除不酸蚀组)差异均有统计学意义(P<0.05),即产生的纳米渗漏值随酸蚀时间的延长而显著增加.E组AP与B组SB和PB相比,纳米渗漏差异不具有统计学意义(P>0.05);而与C组、D组的纳米渗漏差异具有统计学意义(P<0.05),即按操作要求的AP粘结后产生的纳米渗漏均比酸蚀30 s或45 s后分别使用SB和PB粘结剂产生的纳米渗漏小.结论 ①全酸蚀粘结系统与自酸蚀粘结系统均能产生纳米渗漏;②全酸蚀粘结中,牙本质粘结界面的纳米渗漏随酸蚀时间的延长而显著增加,SB受酸蚀时间影响的程度较PB大;③自酸蚀粘结剂AP与全酸蚀粘结剂SB、PB在酸蚀15 s后产生的纳米渗漏无显著差异.     

Effect of ethanol-wet bonding with hydrophobic adhesive on caries-affected dentine

Frequently encountered in clinical practice, caries-affected dentine (CAD) is the most challenging bonding substrate. This study evaluated the effect of ethanol-wet bonding with hydrophobic adhesive to sound dentine and to CAD. In the control groups, prepared sound dentine and CAD were bonded with Adper Single Bond 2 using a traditional water-wet bonding technique. In the experimental groups, the specimens were treated as follows: Group 1, rinsed with stepwise ethanol dehydration; Group 2, immersion in 100% ethanol, three times, for 20 s each time; and Group 3, immersion in 100% ethanol for 20 s. Microtensile bond strength (μTBS) testing was used to evaluate the effects of the different protocols on bonding. The microhardness of debonded dentine surfaces was measured to ensure the presence of CAD. Interfacial nanoleakage was evaluated by field-emission scanning electron microscopy. Treatment significantly improved the μTBS in CAD in Groups 1 and 2, but had no effect on Group 3. Conversely, treatment significantly reduced the μTBS in sound dentine in Groups 2 and 3, but had no effect in Group 1. The presence of nanoleakage varied with the ethanol-wet protocol used. In conclusion, ethanol-wet bonding can potentially improve bond efficacy to CAD when an appropriate protocol is used.     

自酸蚀粘结剂牙本质粘结界面未封闭结构观察

目的观察并评价3种自酸蚀粘结剂(ClearfilTM SE Bond、AdperTM PromptTM、ONE-UP Bond F)牙本质粘结界面的未封闭结构。方法选取人体24颗无龋坏磨牙,用600目碳化硅砂纸在流水冲洗下预备出统一的牙本质粘结面玷污层。分别用3种自酸蚀粘结剂和1种全酸蚀粘结剂(对照组)按使用说明进行粘结处理。每颗牙齿标本垂直于粘结面切割出粘结试件,分别进行氨化硝酸银、三色法染色,观察牙本质粘结界面。结果在电镜和光学显微镜下均观察到3种自酸蚀粘结剂牙本质粘结界面混合层底部的纳米渗漏。结论自酸蚀粘结剂牙本质粘结界面中存在部分脱矿的未封闭牙本质结构。     

Influence of ageing on self‐etch adhesives: one‐step vs. two‐step systems

The aim of this study was to evaluate microtensile bond strength (μTBS) to dentine, interfacial nanoleakage expression, and stability after ageing, of two‐step vs. one‐step self‐etch adhesives. Human molars were cut to expose middle/deep dentine, assigned to groups (n = 15), and treated with the following bonding systems: (i) Optibond XTR (a two‐step self‐etch adhesive; Kerr), (ii) Clearfil SE Bond (a two‐step self‐etch adhesive; Kuraray), (iii) Adper Easy Bond (a one‐step self‐etch adhesive; 3M ESPE), and (iv) Bond Force (a one‐step self‐etch adhesive; Tokuyama). Specimens were processed for μTBS testing after 24 h, 6 months, or 1 yr of storage in artificial saliva at 37°C. Nanoleakage expression was examined in similarly processed additional specimens. At baseline the μTBS results ranked in the following order: Adper Easy Bond = Optibond XTR ≥Clearfil SE = Bond Force, and interfacial nanoleakage analysis showed Clearfil SE Bond = Adper Easy Bond = Optibond XTR> Bond Force. After 1 yr of storage, Optibond XTR, Clearfil SE Bond, and Adper Easy Bond showed higher μTBS and lower interfacial nanoleakage expression compared with Bond Force. In conclusion, immediate bond strength, nanoleakage expression, and stability over time were not related to the number of steps of the bonding systems, but to their chemical formulations.     

Influence of photo-curing distance on bond strength and nanoleakage of self-etching adhesive bonds to enamel and dentin

Objectives. To assess the influence of light-curing unit tip distance on the microtensile bond strength (μTBS) and nanoleakage of self-etching adhesives to enamel and dentin. Materials and methods. Flat buccal surfaces were prepared on 198 bovine incisors. The teeth were randomly assigned into nine groups for μTBS (n = 8) and nanoleakage (n = 3) testing according to the adhesive system (Clearfil Protect Bond, Clearfil Tri-S Bond or One Up Bond F Plus) and distance from the light-curing tip (0, 3 or 6 mm). The bonded samples were tested in tension (0.5 mm/min) and nanoleakage was analyzed using SEM. Results. Clearfil Protect Bond exhibited the highest tensile strength on both enamel and dentin. Leakage was higher in samples exposed at a distance of 6 mm on enamel and 0 mm on dentin. One Up Bond F Plus experienced the greatest amount of nanoleakage on both substrates. Conclusions. Light-curing unit distance did not influence the μTBS of the adhesives, but nanoleakage increased on enamel samples when photoactivation occurred at a distance of 6 mm.     

The role of dentin moisture in the degradation of resin-dentin interfaces under clinical and laboratory conditions

BackgroundThe authors conducted a study to evaluate the influence of dentin moisture on the degradation of the resin-dentin interface in primary teeth under clinical and laboratory conditions.MethodsThe authors prepared 40 Class I restorations (five teeth per group) by using a cylindrical diamond bur, leaving a flat dentin surface on the pulpal floor. They vigorously rubbed two coats of a simplified etch-and-rinse adhesive on either dry or wet demineralized dentin under clinical or laboratory conditions. After performing restorative procedures, the authors extracted teeth prepared under clinical conditions after 20 minutes (immediately) or the teeth exfoliated after six months. The authors also tested the teeth prepared under laboratory conditions immediately or after six months of being stored in water. They sectioned the teeth to obtain resin-dentin bonded specimens for microtensile testing and for silver nitrate uptake (SNU) under scanning electron microscopy. They performed a three-way analysis of variance and Tukey test (α = .05) on the SNU bond strength data.ResultsStatistically higher bond strength values (megapascals [standard deviation]) were observed when bonding was performed under laboratory conditions (clinical = 25.2 [3.6] MPa versus laboratory = 28.5 [4.4] MPa; P < .05). Degradation occurred only in the wet dentin groups under both experimental conditions (immediately = 31.3 [4.5] MPa versus after six months = 21.3 [2.1] MPa; P < .05). SNU occurred in all groups and was statistically higher after six months of clinical function or water storage (immediately = 13.9 [4.9 SD] percent versus after six months = 34.1 [4.5 SD] percent; P < .05).ConclusionsThe bonding of adhesives to dry demineralized dentin produces adhesive interfaces that are more resistant to degradation regardless of the bonding condition.Clinical ImplicationsResin-dentin bond strengths produced under laboratory conditions in primary teeth may be higher than those obtained under clinical circumstances, although both conditions (clinical and laboratory) seemed to yield similar results. Bonding to dry demineralized primary tooth dentin produced resin-dentin interfaces that were more resistant to degradation.     

Bonding to Zirconia Using a New Surface Treatment

Purpose: Selective infiltration etching (SIE) is a newly developed surface treatment used to modify the surface of zirconia‐based materials, rendering them ready for bonding to resin cements. The aim of this study was to evaluate the zirconia/resin bond strength and durability using the proposed technique. Materials and Methods: Fifty‐four zirconia discs were fabricated and divided into three groups (n = 18) according to their surface treatment: as‐sintered surface (control group), airborne‐particle abrasion (50‐μm aluminum oxide), and SIE group. The zirconia discs were bonded to preaged composite resin discs using a light‐polymerized adhesive resin (Panavia F 2.0). The zirconia/resin bond strength was evaluated using microtensile bond strength test (MTBS), and the test was repeated after each of the following intervals of accelerated artificial aging (AA): thermocycling (10,000 cycles between 5 and 55°C), 4 weeks of water storage (37°C), and finally 26 weeks of water storage (37°C). Silver nitrate nanoleakage analysis was used to assess the quality of zirconia/resin interface. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 18, α= 0.05) Results: There were significant differences in the MTBS values between the three test groups at each of the test intervals (p < 0.001). AA resulted in reduction in the bond strength of the as‐sintered and the particle‐abraded groups (5.9 MPa and 27.4, MPa, respectively). Reduction in the bond strength of these groups was explained by the observed nanoleakage across the zirconia/resin interface. The bond strength of the SIE specimens was stable after completion of AA (51.9 MPa), which also demonstrated a good seal against silver nitrate penetration across the zirconia/resin interface. Conclusion: SIE established a strong, stable, and durable bond to zirconia substrates. Conservative resin‐bonded zirconia restorations are now possible using this new technique.     

酪蛋白磷酸肽-无定形磷酸钙对牙本质粘接界面耐pH循环老化的影响

目的 研究局部应用酪蛋白磷酸肽-无定形磷酸钙（CPP-ACP）对牙本质粘接界面耐pH循环老化的影响。方法 常规制备牙本质粘接试件,将其随机分为3组,其中2组行pH循环,期间每日分别加用CPP-ACP、去离子蒸馏水（DDW）处理,15 d后测定微拉伸粘接强度,观察断裂模式、界面形貌及纳米渗漏,并确定混合层内元素含量。另一组试件制备完成后即刻测试。结果 无pH循环组及pH循环/CPP-ACP组微拉伸粘接强度差异无统计学意义,但二者均显著高于pH循环/DDW组（P＜0.05）。试件均以混合破坏为主。pH循环/CPP-ACP组混合层质量优于pH循环/DDW组,纳米渗漏少。无pH循环组及pH循环/CPP-ACP组混合层内Ca含量显著高于pH循环/DDW组,Ag含量显著低于pH循环/DDW组（P＜0.05）。结论 牙本质粘接界面局部应用CPP-ACP可增强界面耐pH循环老化的能力,延缓界面退变。