粘结面润湿度对牙本质粘结强度的影响

目的：研究、比较不同粘结面润湿度对4种粘结剂（OptiBond Solo（OB）、Single Bond（SB）、One-Step（OS）、Prime＆Bond NT（PB））牙本质粘结强度的影响。方法：选取36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。分别用4种全酸蚀粘结剂在不同粘结面润湿度条件下进行粘结处理。每颗牙齿垂直于粘结面切割出8个1.0mm×1.0mm×4.0mm粘结试件，分别进行微拉伸强度（μTBS）测试。结果：4种粘结剂OB（25.24±2.07）MPa、SB（24.28±4.73）MPa、OS（28.29±4.35）MPa和PB（26.87±4.39）MPa在润湿的牙本质粘结面上均取得了最高的牙本质粘结强度（P〈0.01）。结论：不同粘结面润湿度对不同溶剂粘结剂牙本质粘结强度的影响不同。     

Cerinate瓷贴面临床修复色彩学研究及粘结树脂对其颜色的影响

目的：探讨不同颜色不同厚度的瓷贴面能否恢复对应Vna比色的牙齿的原来颜色以及不同颜色的粘结树脂对其颜色的影响。方法：制作不同颜色(A1、A2、A3色)不同厚度(0．50mm、0．75mm、1．00mm)的Cerinate瓷贴面，将其用不同颜色的粘结树脂粘固到对应的牙齿预备面上，用测色仪分别测量牙齿预备前及粘固了Cerinate瓷贴面后牙面的L*a*b*值，比较两者的差异。结果：随着预备深度的增加，两者的L*a*b*值越来越接近，不同颜色的粘结树脂对其色彩的影响越来越小。结论：Cerinate瓷贴面可以恢复牙齿原来的颜色，不同颜色的粘结树脂对Cerinate瓷贴面修复的最终颜色有微调作用。     

人工唾液对瓷贴面粘结剂颜色影响的实验研究

目的:研究人工唾液对瓷贴面粘结剂颜色的影响。方法:用VitaT4透明瓷制作直径10.00mm,厚0.50mm的试样30个,分成A、B、C三组,分别选用三种不同粘结剂与玻璃底座相粘结。A组采用EB化学固化粘结剂粘结,B组采用RelyXVeneer光固化粘结剂粘结,C组采用RelyXARC双重固化粘结剂粘结。然后用分光光度仪测量即刻以及置于人工唾液7天、30天、90天后的试样的L*a*b*值,并计算色差(△E),采用SPSS10.0软件分析结果,比较三种粘结剂的颜色稳定性。结果:随着浸泡人工唾液时间的延长,三组之间的L*a*b*值均无显著性差异(P>0.05),平均△E值分别为1.05、0.60和0.64。但是三组试样的L*a*b*值均随着浸泡时间的延长而发生变化(P<0.05):L*值减小,a*b*值增大。结论:在人工唾液环境中,随着浸泡时间的延长三种粘结剂都会发生变色,但这种颜色的改变程度是在临床美学要求范围内的。     

酸蚀及偶联剂的使用对瓷与树脂剪切粘结强度的影响

目的：评价不同蚀刻处理时间及偶联剂对瓷-树脂粘结强度的影响。方法：烤瓷试件用酸蚀剂分别处理0－210秒，然后一半使用偶联剂，另一半不使用偶联列，与树脂粘结后测试剪切粘结强度。结果：单纯蚀刻可提高瓷与树脂的粘结强度，若与偶联剂联合使用粘结强度可显著提高，但蚀刻后使用偶联剂，蚀刻时间对粘结强度无明显影响。结论：蚀刻处理是提高瓷与树脂粘结强度的重要方法，偶联剂的使用有利于提高粘结强度，并可在短时间内获得理想的粘结强度。     

树脂粘结剂对IPS Empress Ⅰ铸瓷贴面修复颜色的影响

目的：评价树脂粘结剂粘结后IPS EmpressⅠ铸瓷贴面颜色的变化趋势。方法：选择前牙为四环素变色牙、氟斑牙及死髓变色牙的惠牙181颗，采用IPS EmpressⅠ铸瓷贴面修复并用测色仪测色，对修复后颜色变化趋势进行评价。结果：树脂粘结剂粘结后的瓷贴面与对照牙及比色板问颜色均有明显差异。结论：树脂粘结剂对IPS EmpressⅠ铸瓷贴面的颜色有显著影响，提示可尝试通过调配不同比例不同颜色的树脂粘结剂来调节瓷贴面修复的效果。     

正畸托槽不同粘结方法的粘结强度比较

目的:比较托槽间接粘结法同直接粘结法的托槽粘结强度差异。方法:收集96颗因正畸拔除的新鲜人类前磨牙,随机分为A、B和C三组,每组32颗。A组使用改良间接粘结法,B组选用Sondhi推荐的间接粘结法,C组采用直接粘结法。分别检测两组粘结剂残留和托槽的抗剪切强度。结果:3组粘结剂残留存在统计学差异(Z=19.35,P0.05),C组残留率最多,进一步两两比较,A组比B组粘结剂残留较少,但差异不具有统计学意义(t=1.25,P0.05);3组抗剪切强度存在统计学差异(F=7.493,P0.05);进一步两两比较,A组(9.92±3.51)与B组(9.38±2.09)抗剪切强度无统计学差异(P0.05),C组(12.41±4.09)抗剪切强度强于A和B组,且差异有统计学意义(P0.05)。结论:改良间接粘结法与Sondhi法相比,粘结剂残留率较低,抗剪切强度较高,能够满足临床需要。     

自酸蚀粘结剂联合流体树脂修复楔状缺损的疗效观察

目的：探讨自酸蚀粘结剂联合流体树脂修复楔状缺损的疗效。方法：对21例患者共126颗牙髓活力正常的牙颈部楔状缺损分别进行充填治疗,随机分成实验组和对照组,每组63颗牙。实验组使用CLEARFIL S3 BONDTM自酸蚀粘结剂和流体树脂进行充填;对照组常规酸蚀,涂布粘结剂和复合树脂充填。评价两组6个月、1年、2年的保留成功率。结果：两组在治疗后6个月,成功率差异无统计学意义;治疗后2年,自酸蚀粘结剂联合流体树脂充填成功率为95%,对照组为76.6%,两组差异有统计学意义（P＜0.01）。结论：自酸蚀粘结剂和流体树脂充填楔状缺损牙髓刺激性小,可明显提高修复充填体的固位率,值得推广应用。     

不同表面处理方法对金属托槽与不同瓷修复体粘结强度影响的研究

目的：研究不同的表面处理方法对金属托槽与不同瓷面粘结强度的影响,为临床托槽粘结前选择合适的陶瓷表面处理方法提供参考依据。方法：选择3种不同的陶瓷材料为研究样本并制作成试件,每种样本按所用的表面处理方法不同分为喷砂、酸蚀、喷砂＋酸蚀处理3个组。使用光固化正畸粘结剂将3种陶瓷试件与金属托槽粘结,在万能材料试验机上剪切、测量后再比较其与金属托槽的抗剪粘结强度。结果：对同一种材料与托槽的粘结强度来说,酸蚀组的粘结强度相对于喷砂＋酸蚀组与喷砂组都要最低（P〉0．05）;而喷砂＋酸蚀组与喷砂组间的粘结强度无统计学差异（P〉0．05）。对于同一种表面处理方法来说,3种材料与托槽的粘结强度无统计学差异（P〉0．05）。3种材料与3种处理方法间无交互作用（P〉0．05）。结论：陶瓷修复体所用材料的不同,不对其与金属托槽的粘结强度造成影响。为了提高陶瓷修复体与金属托槽的粘结强度,相对于酸蚀方法,喷砂处理是一种优选的表面处理方法,而喷砂后的酸蚀处理则是没有必要的。     

“劲润”牙本质保护膜的牙本质粘结性能探讨

目的：探讨“劲润”牙本质保护膜（Hybrid Coat,HyC）的牙本质粘结性能。方法：选取A组（HyC）和其他3组不同类型的牙本质粘结剂：B组（G-Bond）、C组（MegaBond）和D组（single Bond）,比较其对牛牙牙本质的剪切粘结强度,并用实体显微镜观察粘结界面断裂模式。各组试料数分别为n=10,结果通过Tukey-Kramer（P〈0．05）进行统计学分析。结果：B、C、D组均显示了较大的粘结强度,3组之间无统计学差异。A组（HyC）显示了较低的粘结强度,约10．08MPa,与其他3组之间存在显著性差异。断裂模式显示,A组（HyC）以界面破坏为主,而其他3组以凝集破坏和混合破坏为主。结论：本研究结果提示,“劲润”牙本质保护膜（HyC）的粘结强度弱于其他3组牙本质粘结剂。为了保证HyC长期稳定的防过敏效果及粘结性能,在今后的研究中有必要进一步探讨如何提高HyC的牙本质粘结性能。     

两种漂白方法对牙本质与树脂粘结强度影响的实验研究

目的：比较牙本质经两种漂白方法漂白后,在不同时间粘结树脂其抗剪强度变化。方法：25颗恒前磨牙随机分为5组。A组为对照组：人工唾液内3周后制备牙本质粘结面,粘结树脂;B组：牙齿外漂白每天6h,共3周后制备牙本质粘结面,粘结树脂;C组：牙齿外漂白3周,人工唾液内储存2周后制备牙本质粘结面,粘结树脂;D组：牙齿内漂白3周后制备牙本质粘结面,粘结树脂;E组：牙齿内漂白3周,人工唾液内储存2周后制备牙本质粘结面,粘结树脂。电子万能实验机测试剪切粘结强度。结果：①抗剪强度测试结果：A组（18.61±3.56）MPa,B组（10.74±3.03）MPa,C组（17.21±3.15）MPa,D组（12.10±2.64）MPa,E组（16.78±2.84）MPa;②统计学分析：A-E组试件的剪切强度值单因素方差分析（one-wayANOVA）表明5组样本均数之间存在统计学差异（P〈0.05）。各组均数两两比较（Student-Newman-Keuls,SNK-q法）显示A与B组,A与D组,B与C组,D与E组的剪切强度值差别有统计学意义（P〈0.05）,而A与C组,A与E组,B与D组,C与E组的剪切强度值之间无统计学差异（P〉0.05）。结论：①两种漂白方法对牙本质与树脂粘结强度的影响无明显差别;②牙齿漂白后即刻粘结树脂,两种漂白方法均会降低牙本质与树脂的粘结强度;③牙齿漂白后延迟2周再粘结树脂,两种漂白方法均能够恢复牙本质与树脂的粘结强度接近未漂白组的水平。     

Influence of surface treatments and resin cement selection on bonding to zirconia

This study aimed to evaluate the surface changes caused in zirconia by different surface treatments and the influence of the surface treatment and cement selection on bonding to zirconia under aging. Sintered zirconia specimens were divided into five groups (n?=?31) based on the surface treatment, namely, control, air abrasion, silica coating, laser and air abrasion + laser. After surface treatment, surface roughness and microscope analyses were performed on one specimen of each group. Composite cylinders were then bonded to conditioned ceramics using RelyX U100 (RXU), Clearfil Esthetic Cement (CEC) and Panavia F (PF) (n?=?10). After 24 h, the bonded specimens were subjected to thermal cycling (6,000 times), and then, a shear bond strength test was conducted. The roughness values were analysed using Kruskal–Wallis and Mann–Whitney U tests, and the bond strengths were analysed by two-way analysis of variance and Duncan's test. The relationship between the roughness and the bond strength was determined by Spearman's correlation analysis. Specimens subjected to surface treatments were rougher than the control specimen (p?<?0.000). However, there were no significant differences between the air abrasion and air abrasion + laser groups and the silica coating and laser groups. Specimens treated with laser showed lower bond strengths irrespective of the resin cement used. CEC and/or PF showed higher bond strengths than RXU for each surface treatment group. No significant relationship was observed between the roughness and the bond strength. The results of this study showed that all the surface treatments, except for laser irradiation, were suitable for treating zirconia ceramics. Cement selection was found to be more important than surface treatment, and phosphate monomer-containing cements were suitable for cementing zirconia.     

正畸粘结树脂改良型玻璃离子粘固剂的研究进展

直接粘结技术已在口腔正畸临床得到广泛的应用，成功地矫治了各种牙颌畸形，改变了过去多带环技术所无法克服的操作复杂等缺点，且各种正畸粘合剂也不断地研制成功，推动着固定矫治技术的不断发展。一种粘接材料能否应用于临床，关键要考察其粘接强度。以往的研究证实，传统型玻璃离子粘固剂的粘接强度明显低于复合树脂釉质粘接剂的粘接强度，正畸治疗中托槽脱落率较高，不能满足临床要求。20世纪90年代以后出现的树脂改良型玻璃离子粘固剂在材料成分上有了改变，使材料性能得以改进，尤其在粘接强度上较传统型玻璃离子粘固剂有了明显提高，使其有可能应用于正畸临床中。近年来的研究集中在应用树脂改良型玻璃离子粘固剂粘接正畸托槽方面，并已成为正畸研究领域的热点之一。本文对近年来改良型玻璃离子粘固剂的研究发展状况进行回顾，关于树脂改良型玻璃离子粘固剂具有以下几个方面的特性.     

Correlation between flexural and indirect tensile strength of resin composite cements

Background

To evaluate a potential correlation between flexural strength and indirect tensile strength in assessing the mechanical strength of resin composite cements.

Methods

Flexural strength (n?=?5) and indirect tensile strength (n?=?5) of 7 resin composite cements (RelyX Unicem 2 Automix [RXU], Panavia SA [PSA], Clearfil SA [CSA], Panavia F2.0 [PF2], Multilink Implant [MLI], DuoCem [DCM], Panavia 21 [P21]) were determined. Specimens were either auto-polymerized or dual-cured (except P21) and stored in water at 37 °C for 1 day prior to measurement. Flexural and indirect tensile strength of 4 cements (RXU, PSA, PF2, MLI) was additionally measured directly after curing and after 96 h water storage at 37 °C.

Results

Except for PF2, dual-cured specimens achieved higher flexural strength than auto-polymerized specimens. In the indirect tensile strength test differences in auto-polymerized and dual-cured specimens were only detected for RXU and DCM. A general non-linear correlation was found between flexural and indirect tensile strength values. However, strength values of auto-polymerized and dual-cured specimens did not generally correlate.

Conclusions

Flexural strength and indirect tensile strength of resin composite cements are correlated. At high strength values the indirect tensile test is less sensitive than the flexural test. The results suggest that the indirect tensile test may only be recommended as a screening test especially for low or medium strength resin composite cements.

     

Effect of feldspathic ceramic surface treatments on bond strength to resin cement

OBJECTIVE: The objective of this study was to evaluate the shear bond strength of resin cement to feldspathic ceramic with various surface treatments. BACKGROUND DATA: Application of adhesive techniques is well established in restorative dentistry, yet the influence of surface treatments on the bond strength of resin cement to ceramic materials prior to luting or repair procedures remains unclear. METHODS: One hundred samples made of a feldspathic ceramic were divided into 10 groups (n = 10): (1) control (no treatment); (2) 10% hydrofluoric acid (HF); (3) 37% phosphoric acid (H(3)PO(4)); (4) 1.23% acidulated phosphate fluoride acid (APF); (5) diamond bur; (6) air abrasion with Al(2)O(3); (7) Al(2)O(3) + HF; (8) CoJet-Sand; (9) Er:YAG laser, and (10) Al(2)O(3) + Er:YAG laser. Afterwards, silane was applied and a resin cement cylinder was built. After 24 hours at 37 degrees C, the prepared specimens were submitted to a shear bond strength test and stereoscopic evaluation to determine the type of failure after rupture. RESULTS: Bond strength means were statistically different for the different surface treatments. The highest bond strengths were obtained with HF, CoJet-Sand, and Al(2)O(3). The groups treated with Al(2)O(3) + Er:YAG laser, diamond bur, and Al(2)O(3) + HF had moderate bond strengths. The lowest bond strengths were obtained with H(3)PO(4), APF, Er:YAG laser, and the control group. CONCLUSIONS: The HF, CoJet-Sand, and Al(2)O(3) techniques were the most effective surface treatments. The null surface treatment proposed with the Er:YAG laser showed low bond strength, and seems to be inadequate for clinical use with the parameters tested.     

Effects of lamination on the strength of bone cement

To improve cement penetration into the cancellous bone of the acetabulum in hip arthroplasty, sequential cementation of each anchoring hole may be feasible. Since this procedure creates laminations in the cement, we have determined the conditions under which such laminations affect the strength of the cement.

Cement bars made at 2, 3 or 4 minutes after the start of cement mixing and with either dry laminations or laminations including blood or saline were tested for tensile strength. Solid unlaminated bars were used as References. Dry and saline laminations made up to 4 minutes after the start of cement mixing did not reduce the strength of the cement. However, there was a time-dependent decrease in cement strength if blood was entrapped in the interface. In such cases, there was a decrease in strength for laminations made at 4 minutes, at 3 minutes this was less pronounced and at 2 minutes no weakening at all was noted.

Our findings indicate that a sequential cementation procedure is permissible as regards cement strength, provided it is performed within 2-3 minutes after the start of cement mixing. If the cement area is kept free from blood, the time may be prolonged up to 4 minutes, without the risk of weakening the cement strength.     

Effect of aging and curing mode on the compressive and indirect tensile strength of resin composite cements

Background

Resin composite cements are used in dentistry to bond ceramic restorations to the tooth structure. In the oral cavity these cements are subjected to aging induced by masticatory and thermal stresses. Thermal cycling between 5 and 55 °C simulates the effect of varying temperatures in vitro. Purpose of this study was to compare indirect tensile to compressive strength of different cements before and after thermal cycling. The effect of the curing mode was additionally assessed.

Methods

Indirect tensile strength and compressive strength of 7 dual-curing resin composite cements (Multilink Automix, Multilink SpeedCem, RelyX Ultimate, RelyX Unicem 2 Automix, Panavia V5, Panavia SA Plus, Harvard Implant semi-permanent) was measured. The specimens were either autopolymerized or light-cured (n =?10). The mechanical properties were assessed after 24 h water storage at 37 °C and after aging (20,000 thermo cycles) with previous 24 h water storage at 37 °C.

Results

Indirect tensile strength ranged from 5.2?±?0.8 to 55.3?±?4.2 MPa, compressive strength from 35.8?±?1.8 MPa to 343.8?±?19.6 MPa.

Conclusions

Thermocyclic aging of 20,000 cycles can be considered a suitable method to simulate the degradation of indirect tensile strength but not compressive strength of resin composite cements. The effect of thermocycling and the curing mode on the resin composite cements is material dependent and cannot be generalized.

     

Bond strength of resin cement to zirconia ceramic with different surface treatments

Zirconia-based ceramics offer strong restorations in dentistry, but the adhesive bond strength of resin cements to such ceramics is not optimal. This study evaluated the influence of surface treatments on the bond strength of resin cement to yttrium-stabilized tetragonal zirconia (Y-TZP) ceramic. Seventy-five plates of Y-TZP ceramic were randomly assigned to five groups (n?=?15) according to the surface treatments [airborne particle abrasion, neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation (Fidelis Plus 3, Fotona; 2 W, 200 mJ, 10 Hz, with two different pulse durations 180 or 320 μs), glaze applied, and then 9.5 % hydrofluoric acid gel conditioned, control]. One specimen from each group was randomly selected, and specimens were evaluated with x-ray diffraction and SEM analysis. The resin cement (Clearfil Esthetic Cement, Kuraray) was adhered onto the zirconia surfaces with its corresponding adhesive components. Shear bond strength of each sample was measured using a universal testing machine at a crosshead speed of 1 mm/min. Bond strengths were analyzed through one-way ANOVA/Tukey tests. Surface treatments significantly modified the topography of the Y-TZP ceramic. The Nd:YAG laser-irradiated specimens resulted in both increased surface roughness and bond strength of the resin cement. The highest surface roughness and bond strength values were achieved with short pulse duration. Nd:YAG laser irradiation increased both surface roughness of Y-TZP surfaces and bond strength of resin cement to the zirconia surface.