漂白剂对复合树脂的影响

临床上常需要对存在复合树脂修复体的牙进行漂白,或者对漂白后的牙进行复合树脂修复。由于漂白剂具有较强的氧化性及反应活性,在一定程度上影响了复合树脂的性能如微硬度、表面粗糙度等;因此,研究漂白剂对复合树脂的影响有重要的临床意义。本文就漂白剂对复合树脂表面性能、与釉质和牙本质粘接强度、微渗漏、颜色等的影响作一综述。     

不同抛光方法对三种复合树脂抛光效果的比较

目的：确定合理有效的复合树脂抛光方法,为临床操作提供实验依据。方法：通过测定Palfique,Z350,Charisma三种复合树脂试件的表面粗糙度和光泽度,对6种抛光方法进行评价。结果：（1）Sof-Lexdiscs抛光碟的抛光效果优于Composite polishing kitCA0310;SuperBuff Set水溶性抛光轮能更好的满足临床修复要求。（2）电镜：Charisma、Palfique、Z350三种树脂经Composite polishing kitCA0310打磨套装处理后,表面都留下了较明显的波浪状划痕,Sof-Lexdiscs抛光碟打磨后的表面划痕减少;配合使用SuperBuff Set水溶性抛光轮后,三种树脂试件划痕明显减少,表面趋于光滑。结论：复合树脂修复后,配合使用精细抛光能更好的提高修复体表面滑泽度。     

Effect of in-office bleaching agents on the color changes of stained ceromers and direct composite resins

Purpose. To evaluate the effect of two in-office bleaching agents on the color changes of two ceromers (Ceramage and Adoro SR) and one direct composite resin (Gradia Direct Anterior) after staining by tea and coffee. Materials and methods. Twenty-four disk-shaped specimens were fabricated for each resin material and randomly divided into three groups (n = 8). The specimens were immersed in tea, coffee or deionized water, respectively, for 7 days. Each group was then equally divided into two sub-groups (n = 4), which were subjected to two in-office bleaching agents (BEYOND and Opalescence Boost), respectively. The color of the specimens was measured by a spectrophotometer at baseline, after staining and after bleaching. The color differences (ΔE values) between baseline and after treatments were calculated. Results. Statistical analysis indicated that the staining solution had significant influence on the color change of resin composites tested (p < 0.001). The discolorations of resin composites were perceptible after immersing in tea or coffee solutions (ΔE>2.0). There was no statistically significant difference between BEYOND and Opalescence Boost in stains removal from discolored resins (p = 0.550). The color changes in ΔE value between baseline and after bleaching were less than 2.0 for all resin composite groups. Conclusions. Tea solution produces severe discoloration of three resin composites tested. The two in-office bleaching agents can effectively remove the stains from two ceromers and one direct composite resin tested in this study.     

抛光对三种复合树脂表面粗糙度影响的实验研究

目的：采用临床上常用的3种充填用光固化复合树脂进行抛光后对比研究,为临床医师选择适当的牙体充填材料提供指导。方法：选择3种临床常用的前后牙通用光固化型复合树脂（Filtek Z250,Spectrum TPH,CHARISMA）,均用Sof-lex抛光系统修整、抛光,扫描电镜观察抛光前和抛光后的表面形态,并用表面粗糙度仪测定其粗糙度,对检测结果进行统计学分析。结果：3种复合树脂经同一种抛光系统处理后粗糙度值均增大,不同复合树脂之间的两两比较显示存在显著性差异;Filtek Z250组表面粗糙度值（Surface Roughness,Ra）无论抛光前后,均较其他两种树脂的Ra值小。结论：用Sof-lex抛光系统修整、抛光,Filtek Z250在三种复合树脂中有较/最佳的抛光性能。     

三种抛光系统对不同光固化复合树脂表面粗糙度影响的实验研究

目的：采用临床上常用的3种充填用光固化复合树脂,经过3种不同抛光系统处理后,观测其表面粗糙度的变化。方法：选择3种临床常用的前后牙通用光固化型复合树脂（FiltekZ250,SpectrumTPH,CHARISMA）,分别用3种抛光系统（sof—lex,Enhance,Super—Snap）修整、抛光,应用表面粗糙度仪测定其粗糙度,扫描电镜观察抛光后的表面形貌,然后对检测结果进行统计学分析。结果：3种复合树脂经不同抛光系统处理后,两因素析因设计方差分析检验树脂材料和抛光系统之间的相互关系,结果显示,二者之间具有交互作用。用Sof—lex处理FiltekZ250树脂可获得最低的Ra值,但Super-snap抛光套装处理各种复合树脂组间无显著差异,均能达到较低的粗糙度值。结论：（1）临床上常用的3种光固化复合树脂材料中,FiltekZ250与SpectrumTPH、CHARISMA相比有更好的抛光性能,可形成比较平整光滑的表面;（2）不同抛光系统和不同树脂之间存在交互作用,Sof-lex和Super—snap最适宜处理FiltekZ250树脂,抛光后的表面光滑;Super-snap抛光系统对3种不同复合树脂进行处理后,均能达到较低的粗糙度值,明显优于其它2种抛光系统。     

冷光漂白对光固化复合树脂表面微硬度和表面粗糙度的影响

目的:研究冷光漂白对4种光固化复合树脂表面微硬度和表面粗糙度的影响。方法:取临床常用的4种复合树脂(Gradia Direct、Z350XT、Premisa、Précis),分别制备成直径10 mm,厚2 mm的圆片状试件。从每种试件中各取20个试件,将其各随机分成两组(n=10),实验组接受冷光漂白处理,另一组不作任何处理,置于蒸馏水中作为对照;漂白处理结束后,用显微显微硬度计检测各组各试件的表面微硬度。然后再分别从每种树脂试件中各取3个试件,分别在冷光漂白处理前和处理后用原子力显微镜(AFM)对各试件表面进行扫描,检测其表面粗糙度。用SPSS 19.0统计软件对数据(±s)进行统计分析。结果:4种树脂试件经冷光漂白处理后表面微硬度值均较其对照组明显降低(P<0.05);冷光漂白后,各试件的表面粗糙度值均明显变大(P<0.05)。结论:冷光漂白处理可降低复合树脂的表面微硬度,并使其表面粗糙度增大。     

Effect of bleaching versus repolishing on colour and surface topography of stained resin composite

Background: The aim of this study was to examine the effect of ozonated gel, carbamide peroxide bleaching agent and polishing paste on the colour and surface topography of stained resin composite. Methods: Ninety disc‐shaped resin composite specimens were used in this study. They were randomly divided into three groups of 30 specimens each according to the immersion solutions used, i.e., tea, cola or artificial saliva. Each group was further subdivided into three equal subgroups (n = 10) according to the type of whitening treatment applied; 30% carbamide peroxide, ozonated KY gel or polishing paste. Colour and surface roughness was measured at baseline, after immersion, also following whitening procedures by using a stereomicroscope. The results were recorded, tabulated and statistically analysed. Results: The colour values of artificial saliva displayed the highest statistically significant mean colour difference compared to cola and tea. However, there was no statistically significant difference in surface roughness. Also, a superior whitening effect was demonstrated with ozonated gel. Ozonated gel showed statistically significant lowest roughness compared to both carbamide peroxide and polishing paste. Conclusions: Immersion solutions have a positive influence on the colour of resin composite. Also, ozonated gel is an efficient bleaching agent with the least adverse effect on surface roughness.     

The effect of mechanical and chemical polishing techniques on the surface roughness of denture base acrylic resins

Smooth polished surface of dental prostheses is important to prevent bacterial colonization and plaque accumulation. The acrylic base of prosthodontic appliances needs to be adjusted by grinding which often alters the surface of the denture base. It is therefore important to know how different polishing techniques affect surface roughness of acrylic resin.

Objective

The aim of this study was to evaluate the effect of mechanical polishing (MP) and chemical polishing (CP) on the surface roughness of heat cured (HC) and auto cured (AC) denture base acrylic resins.

Materials and methods

Sixty acrylic resin specimens (30 × 15 × 3 mm) were made for each of the two types of acrylic resins. Thirty HC specimens received mechanical conventional lathe polishing using cone with pumice slurry and soft brush with chalk powder. The other thirty HC specimens received chemical polishing by immersing in methyl-methacrylate monomer heated to 75 °C ± 1 °C for 10 s. The sixty AC specimens received mechanical and chemical polishing in the same manner. Surface roughness was measured using surface analyzing instrument in microns. The data were statistically analyzed by two-way analysis of variance (ANOVA) followed by post hoc Tukey’s test (α = 0.05).

Results

The surface roughness mean in microns in order of decreasing values were: CP-HC: 1.4132 μm; CP-AC: 1.3494 μm; MP-AC: 0.7364 μm and MP-HC: 0.6333 μm. Two-way ANOVA revealed that the MP-HC was significantly different from CP-HC and CP-AC (P < 0.05). The MP-AC is also significantly different from CP-HC and CP-AC (P < 0.05). There was no significant difference between MP and CP of HC and AC acrylic resin groups.

Conclusion

It can be concluded that MP produced significantly smoother surfaces than CP. The surface roughness obtained by MP was not influenced by acrylic resin type where as this was not true for CP.     

聚合后热压处理对不同表面处理的铸钛与聚合瓷结合强度的影响

目的 研究聚合后热压处理对不同表面处理的铸钛与聚合瓷结合强度的影响。方法 将30个金属试件随机分为5组：光滑组（A组）、喷砂组（B组）、酸蚀喷砂组（C组）、喷砂热压组（D组）、酸蚀喷砂热压组（E组）,根据分组对试件进行相应处理并涂布聚合瓷,测试其剪切结合强度及表面显微硬度,并对钛与聚合瓷断裂面的形貌进行扫描电镜观察。结果 A、B、C、D、E组的剪切结合强度分别为（5.92±0.54）、（10.25±0.55）、（14.97±0.88）、（14.41±0.63）、（19.95±0.52） MPa,除C组与D组间无统计学差异外,其余两组之间均有统计学差异（P<0.01）。B、C、D和E组的钛表面可见部分聚合瓷残留于金属表面。D、E组的显微硬度值高于B、C组（P<0.05）。结论 聚合后热压处理可以显著提高钛与Ceramage聚合瓷的结合强度及聚合瓷的表面显微硬度。     

Effect of nonvital bleaching with 10% carbamide peroxide on sealing ability of resin composite restorations

AIM: To (i) determine the effect of nonvital bleaching with 10% carbamide peroxide on the sealing ability of resin composite restorations bonded with a self-etching adhesive system; and (ii) compare the effects of antioxidant treatment and delayed restoration after bleaching on marginal seal. METHODOLOGY: Forty-eight noncarious maxillary incisors were divided into four groups (n=12) after conventional root canal treatment was completed. In group 1, access cavities were restored with a self-etching adhesive system and resin composite. In the remaining three groups, 10% carbamide peroxide bleaching gel was placed into the access cavities for periods of 8 h per day for 1 week. They were then restored in the same manner as group 1. Group 2 consisted of specimens restored immediately after bleaching. Group 3 specimens were treated with the antioxidant, 10% sodium ascorbate, whereas group 4 specimens were immersed in artificial saliva for 1 week before restoration. Ten specimens in each group were then subjected to dye leakage; the remaining 2 specimens were examined in a SEM (Jeol/JSM 5200, Tokyo, Japan). The dye penetration was assessed with the standard scoring system. Statistical analysis was carried out using the Kruskal-Wallis and the Mann-Whitney tests. RESULTS: Groups 1, 3 and 4 exhibited similar leakage patterns and significantly less leakage than group 2 (P<0.0083). SEM examination of groups 1, 3 and 4 specimens demonstrated close adaptation of resin composite to cavity walls, whereas group 2 specimens did not. CONCLUSION: Nonvital bleaching with 10% carbamide peroxide adversely affected the immediate sealing ability of resin composite restoration; both 10% sodium ascorbate treatment and a 1-week delay in restoration following bleaching improved the reduced sealing ability of resin composite.     

Influence of staining solutions and whitening procedures on discoloration of hybrid composite resins

Abstract

Objectives. The aim was to evaluate the color stability and water uptake of two hybrid composite resins polymerized in two different conditions after exposure to commonly consumed beverages. In addition, the effect of repolishing and bleaching on the stained composite was evaluated. Methods. Eighty specimens (12 mm × 12 mm × 3 mm) were made from two hybrid composite resins of shade A2. Forty specimens of each composite were divided into two groups (n = 20 per each) according to the curing method used (hand light cure HLC or oven light cure OLC). Then each group (HLC or OLC) was sub-divided randomly into four sub-groups (n = 5), which were immersed for 60 days in different beverages (distal water, coffee, tea and pepsi) and incubated at 37°C. Water uptake was measured during this time and followed by measurement of color difference (ΔE) by using a spectrophotometer. After complete staining, repolishing (grit 4000 FEPA at 300 rpm under water) and bleaching (40% hydrogen peroxide bleaching gel) were conducted. The repolished and bleached specimens were submitted to new color measurements. Results. Color value of the specimens immersed in tea displayed the highest statistically significant (p < 0.05) mean color difference (ΔE) compared to other beverages, whereas the ΔE value of pepsi was significantly lower than the others. After staining of the composite resins, both the bleaching and repolishing were able to reduce the ΔE value. Conclusions. All beverages used affected the color stability of tested composite resins. The effect of beverages on color change of composites depends on type of beverage and water uptake value of resins used. A superior whitening effect was obtained with repolishing technique compared to bleaching.     

铸钛的不同表面处理对钛-聚合瓷结合强度影响的实验研究

目的 研究铸钛的不同表面处理方法对钛-聚合瓷结合强度的影响。方法 将24个铸钛试件随机分为光 滑组、粗糙组、酸蚀光滑组和酸蚀粗糙组,每组6个。根据分组不同分别采用不同的表面处理方式,粗糙组进行喷 砂处理,酸蚀光滑组进行酸蚀处理,酸蚀粗糙组喷砂后进行酸蚀,光滑组表面不做处理。表面处理后的钛试件与 聚合瓷制备成钛-聚合瓷试件,测试其剪切结合强度,并在扫描电镜下观察钛表面形貌和剪切试验后钛与聚合瓷断 裂面的形貌。结果 光滑组、粗糙组、酸蚀光滑组和酸蚀粗糙组的剪切结合强度分别为（3.08±0.45）、（6.05±0.74）、（6.27±0.80）、（10.16±0.82）MPa。粗糙组、酸蚀光滑组和酸蚀粗糙组的剪切结合强度高于光滑组（P<0.01）,其中酸 蚀粗糙组的剪切结合强度最高,粗糙组和酸蚀光滑组间的剪切结合强度无统计学差异（P>0.05）。各组的钛表面形
貌和剪切试验后钛与聚合瓷断裂面的形貌均有一定的差异。结论 钛表面酸蚀处理和喷砂处理可提高钛-聚合瓷的剪切结合强度,喷砂后酸蚀处理是一种有效地提高钛-聚合瓷剪切结合强度的表面处理方法。     

Sealing capacity of a photochromatic flowable composite as protective base in nonvital dental bleaching

AIM: To evaluate microleakage of a flowable composite used as a protective isolating base, applied with different adhesive systems. METHODOLOGY: Seventy root-filled teeth were divided into seven groups. A flowable composite base (Tetric Flow Chroma) was used with three adhesive techniques (Syntac, Excite, Excite DCS; in the three cases with and without acid etching) and in a control group without dentine conditioning or adhesive placement. A 30% hydrogen peroxide solution was applied for 24 h in the pulp chambers, followed by the placement of a dye (silver nitrate) for 4 h. Each tooth was sectioned longitudinally, and examined under 4x magnification to assess the tooth/restoration dye leakage following a four-degree scale. Percentage of dye penetration was registered. Statistical analysis was made through the Tukey and Mann-Whitney U-tests. RESULTS: Maximum leakage (100% of specimens) was recorded in the control group without an adhesive system. In the groups subjected to acid etching, the percentage of leakage corresponded to Excite DSC (10%), followed by Syntac (20%) and Excite (30%). In the groups in which only an adhesive system was used, 50% of the teeth demonstrated dye leakage. Statistically significant differences in terms of leakage were observed between the control group and the experimental groups (P < 0.05). There were no significant differences among the experimental groups, but comparing the leakage percentages obtained between the groups in which the teeth were subjected to prior acid etching, and those in which no etching was carried out, observed differences were significant (P = 0.04). CONCLUSIONS: There were no significant differences between the adhesive systems in terms of leakage. Acid etching significantly reduced leakage.     

Influence of surface roughness on streptococcal adhesion forces to composite resins

Objective

To determine streptococcal adhesion forces with composite resins with different surface roughness.

Methods

Polishing and grinding were applied to obtain smooth (roughness 20 nm), moderately rough (150 nm) and rough (350 nm) surfaces of two orthodontic, light-cured composites. Adhesion forces between Streptococcus sanguinis and Streptococcus mutans and the composite surfaces were measured using atomic force microscopy in absence or presence of a salivary conditioning film. Initial adhesion forces were measured as well adhesion after 120 s of contact, as longer contact times are known to result in stronger adhesion forces (“bond-strengthening”). Surface roughness in absence and presence of salivary conditioning films were compared using ANOVA, while adhesion forces were subjected to a Weibull analysis.

Results

Initial adhesion forces in absence of a salivary conditioning film amounted between −0.7 and −0.9 nN for smooth composite resins and increased between −1.0 and −2.0 nN for the roughest surfaces. Streptococcal adhesion forces after bond-strengthening were significantly stronger than upon initial contact, irrespective of the composite type. Salivary conditioning films significantly decreased the surface roughness of the composites, as well as the streptococcal adhesion forces. Yet, also in the presence of a conditioning film, rougher composite surfaces exerted stronger adhesion forces, irrespective of composite type or bacterial strain.

Conclusion

Streptococcal adhesion forces to orthodontic composite resins increase with increasing roughness of the composite surfaces. Composite surface roughness less affects adhesion forces with S. mutans than with S. sanguinis.     

Microleakage effect on class V composite restorations with two adhesive systems using different bleaching methods

Abstract

Objective. The main objective of this study was to evaluate the effects of an at-home and two in-office (chemically activated and KTP laser-activated) bleaching methods on the microleakage of composite resin restorations bonded with etch-and-rinse and self-etch adhesive systems. Materials and methods. Class V cavity preparations were performed on 96 premolars and teeth were divided into two groups according to the two adhesive systems (etch-and-rinse and self-etch). After cavities were restored with an adhesive systems and composite resin, they were submitted to thermocycling procedures. Teeth were divided into four sub-groups according to the bleaching systems (control, at-home bleaching, chemically activated office bleaching and KTP laser-activated office bleaching). After the bleaching procedure, teeth were evaluated for marginal leakage. All data were analyzed using the Mann-Whitney U and Kruskal-Wallis tests (p < 0.05). Results. The results of the present study showed that the control group presented lower microleakage values compared with the groups treated with bleaching agents, except for the chemically activated in-office bleaching. When the scores of microleakage at the enamel and gingival margins of the four groups were compared, the differences among the groups were found to be statistically significant (p < 0.05). Comparing the gingival and enamel margins in each group, statistically significant differences were found in the at-home group (p < 0.05) and no significant differences were seen in the other groups (p > 0.05). No significant difference was found between the adhesive systems after treatment with the same bleaching techniques. Conclusion. Under the conditions of this study, microleakage of composite resin restorations differs according to the bleaching methods used and no difference was found between the adhesive systems.     

Oxygen inhibition layer of composite resins: effects of layer thickness and surface layer treatment on the interlayer bond strength

An oxygen inhibition layer develops on surfaces exposed to air during polymerization of particulate filling composite. This study assessed the thickness of the oxygen inhibition layer of short‐fiber‐reinforced composite in comparison with conventional particulate filling composites. The effect of an oxygen inhibition layer on the shear bond strength of incrementally placed particulate filling composite layers was also evaluated. Four different restorative composites were selected: everX Posterior (a short‐fiber‐reinforced composite), Z250, SupremeXT, and Silorane. All composites were evaluated regarding the thickness of the oxygen inhibition layer and for shear bond strength. An equal amount of each composite was polymerized in air between two glass plates and the thickness of the oxygen inhibition layer was measured using a stereomicroscope. Cylindrical‐shaped specimens were prepared for measurement of shear bond strength by placing incrementally two layers of the same composite material. Before applying the second composite layer, the first increment's bonding site was treated as follows: grinding with 1,000‐grit silicon‐carbide (SiC) abrasive paper, or treatment with ethanol or with water‐spray. The inhibition depth was lowest (11.6 μm) for water‐sprayed Silorane and greatest (22.9 μm) for the water‐sprayed short‐fiber‐reinforced composite. The shear bond strength ranged from 5.8 MPa (ground Silorane) to 36.4 MPa (water‐sprayed SupremeXT). The presence of an oxygen inhibition layer enhanced the interlayer shear bond strength of all investigated materials, but its absence resulted in cohesive and mixed failures only with the short‐fiber‐reinforced composite. Thus, more durable adhesion with short‐fiber‐reinforced composite is expected.     

渗透树脂与前牙美学树脂颜色稳定性的比较研究

目的 通过分析不同树脂材料对饮料色素的着色效果,比较渗透树脂与前牙美学树脂颜色稳定性的差异。方法 选择3种前牙美学树脂（Filtek Z250、Filtek Z350 XT、Beautiful Flow Plus F00）及人工早期龋渗透树脂（Icon）处理样本各20例,不同树脂样本分别分为2组（每组10例）分别置于咖啡溶液及蒸馏水中浸泡1、2、3周。应用Crystaleye分光光度比色仪进行样本颜色分析。结果 人工早期龋渗透树脂处理表面的着色明显高于其他前牙美学树脂（P<0.05）。所有实验树脂及渗透树脂处理表面的着色均随时间延长而增加,但第1周的着色最为显著,明显高于第2周及第3周的着色（P<0.05）。结论 人工早期龋渗透树脂处理表面较前牙美学树脂更易发生颜色改变。