流动性充填材料用于预防性树脂充填的实验研究

目的　以传统的复合树脂+窝沟封闭剂的方法为对照组,用体外实验的方法评价流动树脂、流动复合体在预防性树脂充填(preventiveresinrestoration ,PRR)治疗中的情况。方法　患小面积龋被拔除第三恒磨牙9颗,分别用流动树脂(A组)、流动复合体(B组)和传统的复合树脂材料+窝沟封闭剂(C组)的方法进行PRR治疗。5 0 %AgNO3 浸染法检查微渗漏;用SEM观察树脂与牙齿的结合情况。结果　①渗透实验表明各实验组和对照组中均存在一定程度的微渗漏;在微渗漏率方面,A组低于对照的C组(P <0 .0 5 ) ,在树脂渗透率方面A组低于B组和C组(P <0 .0 5 )。②SEM上显示A与B组相似,多数标本树脂与牙齿接触的界面上有结合良好的树脂突样结构,但树脂在和窝沟底部与牙体组织结合较差,特别在极细窝沟处;C组中结合良好的界面所占比例较少,复合树脂勉强压入窝洞后充填不实,在沟底部常见宽大裂纹。结论　在流动复合体和流动树脂在PRR治疗时更适用于沿窝沟走向侵润的窄长形态的窝沟内龋,而传统PRR法更适用于单个龋损直径在1 .5～2mm左右的圆形或卵圆形的小面积龋,流动性充填材料在PRR治疗中可作为传统法的一种补充,最大限度地保留健康牙体组织。     

Differences in color, translucency and fluorescence between flowable and universal resin composites

OBJECTIVES: To evaluate the optical properties such as color, translucency and fluorescence of flowable resin composites, and compare them with the corresponding shade universal resin composites of the same brand. METHODS: Four brands of flowable and universal resin composites of the same shade designation (A2) were investigated. Color of specimens (2mm in thickness) was measured after polymerization on a reflection spectrophotometer over background of white, black and each corresponding composite material itself. Color differences (DeltaE(ab)(*)) between each combination of resin composites were determined. Translucency parameter (TP) and color difference by the fluorescent emission (DeltaE(ab)(*)-FL) of materials were also calculated. Differences in the optical properties of flowable and universal resin composites were analyzed with one-way ANOVA. RESULTS: DeltaE(ab)(*) between the flowable and the corresponding universal resin composites was in the range of 1.0-6.0 DeltaE(ab)(*) units, which was perceptible (DeltaE(ab)(*)>2.6) in three brands. Flowable resin composites revealed lower TP values in two of the four brands. DeltaE(ab)(*) between flowable and the corresponding universal resin composites was influenced by their difference in translucency. All the four universal resin composites and two flowable resin composites showed fluorescent peak, and the range of DeltaE(ab)(*)-FL was 0.3-2.3 DeltaE(ab)(*) units. CONCLUSIONS: Optical properties of flowable and universal resin composites was significantly different (p<0.05); therefore, differences in color, translucency and fluorescence between the flowable and the corresponding universal resin composites should be considered for clinically acceptable color matching.     

三种铸造合金及其相互作用的细胞毒性评价

目的检测临床常用的钴铬合金、镍铬合金、金合金及其两两合用时的细胞毒性。方法将L-929细胞在含3种合金材料或其两两组合的浸提液中培养后,采用MTT实验评定3种材料单独应用以及两两合用时的细胞毒性。结果镍铬合金的细胞毒性高于钴铬合金和金合金,金合金的细胞毒性最小。钴铬合金和金合金分别与镍铬合金组合后,其细胞毒性较钴铬合金和金合金单独应用时增加,比镍铬合金单独应用时降低;钴铬合金与金合金组合后,其细胞毒性较钴铬合金单独应用时减小。但这3种合金单独应用和两两组合应用时细胞毒性的差异均无显著性（P〉0.05）。结论 3种合金及其两两相互作用时仅具有极微弱的细胞毒性,在临床应用允许范围内。     

Three-year clinical evaluation of a flowable and a hybrid resin composite in non-carious cervical lesions

Objectives

This randomized controlled clinical trial evaluated the 3-year clinical performance of a hybrid (Clearfil AP-X; AP) and a flowable (Clearfil Flow FX; FX) resin composite in 98 non-carious cervical lesions.

Methods

Twenty-two patients, 11 males and 11 females (mean age: 61.9 years, range: 29–78 years) regularly visiting the Nagasaki University Hospital, participated in the study. Each patient received both materials randomly. All restorations (48 restorations for AP and 50 restorations for FX) were placed in conjunction with an all-in-one system (Clearfil S³ Bond) by one dentist. The restorations were blindly evaluated by two examiners at baseline, 6 months, 1, 2 and 3 years using modified USPHS criteria. The data were statistically analyzed using the Cochran's Q-test and Fisher's exact test.

Results

All the patients were examined at each recall. However, five restorations could not be evaluated at 3-year recall as two teeth had been extracted and three restorations had been lost. The only minor problem was the integrity of the enamel margin. The incidence and extent of marginal staining increased with time, but it was still superficial. Marginal staining occurred adjacent to 11 restorations for AP and 12 restorations for FX after 3 years. Neither lesion size nor depth had influence on marginal staining adjacent to each type of resin composite. There were no significant differences in the clinical performances between AP and FX for each variable.

Conclusions

Under the protocol used in this study, both types of resin composite in conjunction with S³ Bond demonstrated an acceptable clinical performance up to 3 years.     

A model of the viscoelastic behavior of flowable resin composites prior to setting

Objective

The aim of this study is to develop fractional derivative models for the assessment of viscoelastic properties related to handling characteristics of dental resin composites belonging to two classes: flowable (Revolution Formula 2 and Filtek Ultimate) and posterior “bulk-fill” flowable base (Smart Dentin Replace).

Methods

Rheological measurements on all materials tested in this study were performed using dynamic oscillatory rheometer at temperature of 23 °C. A parallel plates module with a diameter of 20 mm was used to measure the properties of the resin composites tested. We developed two models to describe the obtained data: the generalized Newton model and the generalized Zener model (the so-called three parameter model). Both models contain fractional derivatives of Riemann–Liouville type. By determining the parameters of the model we were able to fit experimental data with high accuracy.

Results

Our results show that flowable “bulk-fill” resin-composite material (SDR) has distinct properties as compared to other two flowable resin composite materials (Revolution Formula 2 and Filtek Ultimate). Thus, previously found SDR properties as “bulk-fill” flowable base results in the fact that it is described by generalized Zener model (i.e., it has properties of solid like viscoelastic material).

Significance

Our model may be used to predict behavior of tested composites in different flow conditions. The SDR has initially small almost constant complex viscosity showing that it has good self-leveling property.     

流动树脂垫衬联合高强度流动树脂在牙邻面洞修复中的效果分析

目的 探讨流动树脂垫衬联合高强度流动树脂应用于牙邻面洞修复中的效果.方法 选择2018年6月至2019年6月我院收治的牙邻面洞修复患者86例(共86个患牙),按随机数字表法分为两组,各43例.对照组给予夹层修复技术(三明治技术),玻璃离子粘固剂与复合树脂的联合修复;实验组给予流动树脂垫衬联合高强度流动树脂修复.对比两组...     

One-year clinical evaluation of a flowable resin liner associated with a microhybrid resin in noncarious cervical lesions

The aim of this study was to compare the clinical performance over 1 year of a microhybrid composite resin for class V restorations both lined and not lined with a flowable composite resin. Nineteen patients having at least two pairs of cervical noncarious lesions under occlusion were enrolled in this study. A total of 38 restorations were placed, half for each group (Single-Bond + Filtek-Flow + Filtek Z250, and Single-Bond + Filtek Z250). Two calibrated operators placed all restorations according to the manufacturers instructions. Two other independent examiners evaluated the restorations at baseline and after a 12-month period according to the USPHS criteria and modified criteria for color match. The classic alpha score was divided into A1 for not detectable and A2 for slightly discernible filling. Statistical analysis was conducted using Fishers exact test and McNemars test (P=0.05). One restoration was lost after 12 months for each group (retention rate 95% for each group). After 12 months, 18 restorations showed a trend towards dark yellowing (color match A2). The use of Filtek Flow as a liner under Filtek Z250 restorations did not improve the clinical performance of class V restorations after 6 and 12 months of evaluation.     

流动复合树脂衬洞在楔状缺损修复中的疗效评价

目的:评价流动复合树脂作为洞衬材料在楔状缺损修复中的价值。方法:选择85例患者的360颗楔状缺损患牙为研究对象,采用自身对照设计,随机选择每例患者一侧患牙为实验组,采用流动树脂衬洞后再以复合树脂充填;对侧同名牙为对照组,直接采用复合树脂充填。以改良的USPHS/Ryge临床修复体质量评估系统评价修复后1年和3年的疗效。应用SPSS12.0软件包对数据进行统计学处理。结果:实验组在边缘完整性和术后敏感方面优于对照组,有显著性差异。在边缘完整性方面,1年复查时实验组满意率为100%,高于对照组的95.65%(P<0.01);3年复查时实验组满意率为98.56%,高于对照组的92.42%(P<0.01),均有统计学差异。术后1年复查时,实验组未出现敏感病例,而对照组6颗患牙出现中度敏感,需要更换修复体。实验组优于对照组,差异有统计学意义(P<0.05)。结论:流动复合树脂洞衬用于楔状缺损修复可提高边缘完整性和降低术后敏感发生率。     

Assessment of preparation time and 1-year Invisalign aligner attachment survival using flowable and packable composites:: A split-mouth clinical study

ObjectivesTo compare preparation time and 1-year Invisalign aligner attachment survival between a flowable composite (FC) and a packable composite (PC).Materials and MethodsFifty-five participants (13 men and 42 women, mean age ± SD: 24.2 ± 5.9 years) were included in the study. Ipsilateral quadrants (ie, maxillary and mandibular right, or vice versa) of attachments were randomly assigned to the FC group (Filtek Z350XT Flowable Restorative) and the PC group (Filtek Z350XT Universal Restorative) by tossing a coin. The primary outcome was preparation time. The secondary outcome was time to the first damage of an attachment. Preparation times were compared using the paired t-test, and the survival data were analyzed by the Cox proportional hazards model with a shared frailty term, with α = .05.ResultsThe preparation times were significantly shorter with the FC (6.22 ± 0.22 seconds per attachment) than with the PC (32.83 ± 2.16 seconds per attachment; P < .001). The attachment damage rates were 14.79% for the FC and 9.70% for the PC. According to the Cox models, attachment damage was not significantly affected by the attachment material, sex, arch, tooth location, attachment type, presence of overbite, or occurrence of tooth extraction.ConclusionsThe use of a FC may save time as compared with the use of a PC. With regard to attachment survival, there was no significant difference between the two composites. None of the covariates of attachment materials (sex, arch, tooth location, attachment type, presence of overbite, oir occurrence of tooth extraction) affected attachment damage.     

Colour stability and opacity of resin cements and flowable composites for ceramic veneer luting after accelerated ageing

Objectives

Colour changes of the luting material can become clinically visible affecting the aesthetic appearance of thin ceramic laminates. The aim of this in vitro study was to evaluate the colour stability and opacity of light- and dual-cured resin cements and flowable composites after accelerated ageing.

Methods

The luting agents were bonded (0.2 mm thick) to ceramic disks (0.75 mm thick) built with the pressed-ceramic IPS Aesthetic Empress (n = 7). Colour measurements were determined using a FTIR spectrophotometer before and after accelerated ageing in a weathering machine with a total energy of 150 kJ. Changes in colour (ΔE) and opacity (ΔO) were obtained using the CIE L*a*b* system. The results were submitted to one-way ANOVA, Tukey HSD test and Student's t test (α = 5%).

Results

All the materials showed significant changes in colour and opacity. The ΔE of the materials ranged from 0.41 to 2.40. The highest colour changes were attributed to RelyX ARC and AllCem, whilst lower changes were found in Variolink Veneer, Tetric Flow and Filtek Z350 Flow. The opacity of the materials ranged from −0.01 to 1.16 and its variation was not significant only for Opallis Flow and RelyX ARC.

Conclusions

The accelerated ageing led to colour changes in all the evaluated materials, although they were considered clinically acceptable (ΔE < 3). Amongst the dual-cured resin cements, Variolink II demonstrated the highest colour stability. All the flowable composites showed proper colour stability for the luting of ceramic veneers. After ageing, an increase in opacity was observed for most of the materials.     

Cuspal deflection and microleakage in premolar teeth restored with resin-based composites with and without an intermediary flowable layer

OBJECTIVES: To assess cuspal deflection and cervical enamel microleakage with and without an intermediary flowable RBC layer for the incremental restoration of mesio-occluso-distal (MOD) cavities with two resin-based composites (RBCs). METHODS: Forty sound upper premolar teeth had standardised MOD cavities prepared. Restoration of the teeth involved the placement of the RBCs (Filtek P60 or Filtek Supreme) in eight increments with the appropriate bonding system with and without an intermediary flowable RBC layer (Filtek Flow). Buccal and palatal cusp deflections were recorded post-irradiation using a twin channel deflection measuring gauge. Following restoration, the teeth were thermocycled, immersed in a 0.2% basic fuchsin dye for 24h, sagittally sectioned and examined for cervical enamel microleakage. RESULTS: A significant reduction in cuspal deflection was evident when both RBC materials were used to restore the cavity by employing an intermediary flowable (P<0.001) compared with when no intermediary flowable was utilised. No statistically significant differences were identified in microleakage between the teeth restored with Filtek P60 or Filtek Supreme when an intermediary flowable (Filtek Flow) was employed. CONCLUSIONS: The results of the current study suggest that there was a benefit to the operator in terms of a reduction in cuspal deflection but not from the maintenance of the synergism of the adhesive bond, namely microleakage at the cervical enamel cavosurface margin, when an intermediate layer of a flowable RBC was used under higher elastic modulus RBCs.     

Clinical performance of a hybrid resin composite with and without an intermediate layer of flowable resin composite: A 7-year evaluation

Objective

The objective of this prospective clinical follow up was to evaluate the long term clinical performance of a hybrid resin composite in Class II restorations with and without intermediate layer of flowable resin composite.

Methods

Each participant received at least two, as similar as possible, Class II restorations of the hybrid resin composite. One resin composite restoration of each pair (59) was chosen at random to be restored with an intermediary layer with flowable resin composite. The other was restored without. The 118 restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 7 years.

Results

Four drop outs were registered during the 7-year follow up (2 with and 2 without flowable) restorations. A prediction of the caries risk showed that 18 of the evaluated 46 patients were considered as high risk patients. Seventeen failures were observed, 8 in restorations with and 9 in restorations without an intermediate layer of flowable resin composite, resulting in a 14.9% failure rate after 7 years. The main reasons for failure were: fracture of resin composite (8), secondary caries (4) and cusp fracture (3). No statistical difference was seen between restorations restored with and without flowable layer.

Conclusion

The hybrid resin composite showed a good clinical performance during the 7-year evaluation. The use of flowable resin composite as an intermediate layer did not result in improved effectiveness of the Class II restorations.     

两种含氟流动树脂释氟能力的体外研究

目的：体外比较2种含氟流动树脂Beautifil Flow Plus F00和Dyad Flow的短期释氟量,以探讨2种材料释氟能力的差异。方法选取含氟流动树脂F00、DF和不含氟树脂Valux,制备直径10mm,厚1mm的样本,每组10个。将样本分别浸泡于5ml去离子水,第1、2、3、7、14、21、28d使用氟离子选择电极测量去离子水中的氟离子浓度,Va组为对照,比较F00和DF组前3d的单日氟释放及28d内各时间点的累积氟释放情况。结果 F00和Dyad Flow的释氟浓度均第1d最高;前3d单日释氟浓度呈下降趋势,差异有统计学意义(P<0．01);28d内2实验组均有缓慢持续的氟释放,随着时间延长累积释氟量增加;各个时间点,Dyad Flow组累积释氟量高于F00组,差异有统计学意义(P<0．01)。结论2种含氟流动树脂F00和Dyad Flow第1d氟释放最多,在测试时间内均有低量但持续的释氟能力,Dyad Flow释氟量略高于F00。     

粘接托槽牙面流动复合树脂封闭层抗磨耗的实验研究

目的 观察流动复合树脂表面封闭层的耐磨性及其在提高粘接托槽牙面抗磨耗性能方面的作用.方法 40颗离体前磨牙随机分为未脱矿组、自酸蚀组、直接脱矿组、表面封闭后脱矿组,每组10颗.恒温水浴及冷热循环后,直接脱矿组、表面封闭后脱矿组置0.1M的乳酸胶脱矿48h,将4组离体前磨牙制成试件,牙刷磨耗31000次,扫描电镜观察颊面牙釉质结构及封闭层改变情况.结果 磨耗后,未脱矿组牙面未见刷痕;自酸蚀组、直接脱矿组牙面刷痕较深;表面封闭后脱矿组表面封闭层仍保留在牙面;流动复合树脂表面封闭层磨耗前、后的平均厚度（μm）是167.58±6.38、140.93±7.88,平均磨耗量（μm）是26.85±4.48,经配对t检验,磨耗前、后流动复合树脂表面封闭层厚度差异有统计学意义.结论 牙刷磨耗可磨去部分流动复合树脂,但不能去除流动复合树脂表面封闭层;表面封闭法能够提高粘接托槽牙面抗磨耗性能.     

可乐丽菲露AP-X复合树脂对人牙髓细胞毒性的研究

目的 通过细胞毒性试验，探讨可乐丽菲露AP-X复合树脂及其SEBOND粘接系统在临床上用于活髓牙窝洞直接修复术的安全性。方法选用年轻健康人新鲜离体牙髓，以组织块培养法及酶消化法进行原代培养。同时制备各材料样品，浸入DMEM培养基制取材料浸渍液。分别将各材料的浸渍液与第五代人牙髓细胞共同培养，以MTT法评价材料的细胞毒性。结果可乐丽菲露AP-X复合树脂的细胞毒性小于双组份玻璃离子水门汀Vitremer及复合树脂Z100，其差别具有统计学意义，与复合体F2000的细胞毒性无统计学意义的差别。可乐丽菲露的细胞毒性小于复合体F2000和复合树脂Z100对应粘接剂，且其差别具有统计学意义（P〈0．05）。结论可乐丽菲露AP-X复合树脂及其粘接剂的细胞毒性小于临床上现在常用的其他牙色类材料。     

Cytotoxicity of a silorane-based dental composite on human gingival fibroblasts

AIM: To evaluate the direct and indirect biocompatibility of Filtek Silorane on human gingival fibroblastic cells. METHODS: Sixty-three standardized cylindrical specimens (8 mm diameter and 2 mm thickness) of restorative material were prepared using a light emitting diode-curing unit. The sample were built up in one increment and divided in 2 groups. In the first group, 21 samples (unpolished samples) were left without a specific polishing procedure; in the second one, 42 samples (polished samples) were polished with 4 different grains of discs. Fibroblast cultures, obtained from gingiva of 2 subjects without systemic and oral disease, were used to assess the direct and indirect biocompatibility. Cells cultured for 48 h in normal culture medium were used as a control. RESULTS: The scanning electron microscope observations of fibroblasts cultured on the silorane samples, either polished or unpolished, confirmed the good biocompatibility of the material, favouring the cellular spreading. 3-dimethylthiazol-2, 5-diphenyltetrazolium bromide tests showed a significant reduction (P < 0.01) of gingival fibroblasts viability cultured both in polished samples (90.05% ± 19.00%) and unpolished samples (78.15% ± 11.00%) compared with the control. Cells growth in medium conditioned with the samples for 1 wk showed a significant viability reduction (P < 0.01) compared to the control. A reduction of cell viability was observed even in the groups containing the material for 3 wk (polished: 89.45% ± 10.00%; unpolished: 65.97% ± 10.00%), even if the cytotoxicity was reduced after this long time exposure. CONCLUSION: Although the poor chromatic availability of this material remains a big limit that restricts its use to posterior sectors, the silorane-based material can be considered an option to perform restorations when aesthetic demands are not the priority, such as the class II restorations     

牙科复合树脂及其浸出成分的细胞毒性

目的：观察4种含有不同成分的牙科复合树脂的细胞毒性,通过高效液相色谱法分析其浸出的成分。材料和方法：将复合树脂（Z100,Solitaire 2,Filtek P60．Synergy）制备成圆盘状测试试样,采用Balb／C 3T3成纤维细胞进行细胞毒性实验。在37℃条件下．实验第一部分为细胞与树脂接触72h（直接法）,第二部分则是细胞与树脂的乙醇浸泡提取液接触24h（间接法）。用MTT法{[3（4,5二甲基噻唑2）2,5二苯基]四氮唑嗅盐法}检测细胞存活率。结果：牙科复合树脂及其乙醇浸泡提取液对Balb／C 3T3成纤维细胞有毒性作用。单因素方差分析显示直接接触和间接接触各组间的差异均有统计学意义（P〈0.001）。组间比较（Tukey检验．α=0.05）显示直接法检测Synergy的毒性显著低于其他树脂．Solitaire 2毒性显著高于其他树脂。但是．间接法检测则为Synergy的浸泡提取液毒性显著高于其他树脂的提取液。采用高效液相色谱法检测各树脂中Bis—GMA,TEGDMA．UDMA．bis-EMA以及双酚A的含量,结果显示上述成分存在与否和其浓度各不相同。结论：牙科树脂的细胞毒性水平与其化学成分、浸泡介质以及浸出的成分和量相关。     

光固化复合树脂释放成分的检测方法及评价

光固化复合树脂是临床广泛使用的牙体修复材料,在光照发生聚合固化时,有部分单体未发生聚合,成为残余单体,残余单体在口腔环境中进行浸出释放,唾液、酶等也会引起树脂的生物降解从而释放一些成分,这些成分可能对机体组织形成一定的影响。目前有多种检测释放单体的方法,包括高效液相色谱法、液相色谱-质谱联用法、高效液相色谱-质谱联用法、气相色谱-质谱联用法等。该文从残余单体释放的原因及其对人体的影响、检测方法等方面作一综述。     

流动树脂修复楔状缺损的疗效观察

目的 评价流动树脂应用于楔状缺损的临床效果。方法 以40名成年人的55对前磨牙为研究对象,随机分为试验组和对照组。试验组使用Beautifil Flow Plus流动树脂进行充填,对照组使用Filtek Z350流动树脂进行充填。随访1年后观察充填体的脱落率、边缘着色、继发龋及牙髓刺激症状,采用卡方检验分析试验结果。结果 充填术后一年,试验组和对照组的成功率分别为81.82%和70.91%,组间差异无统计学意义（p>0.05）。结论 Beautifil Flow Plus流动树脂具有良好的充填性能,在临床上可应用于楔状缺损的充填。     

Surface morphology and mechanical properties of new-generation flowable resin composites for dental restoration

Objectives

The purpose of this study was to characterize the surface morphology and the elastic properties of four dental restorative flowable composites currently on the market (Venus Diamond Flow, Vertise Flow, Filtex Supreme XT Flow, Surefil SDR Flow). Additionally, one adhesive system (Adhese One F) and one non-flowable composite (Venus Diamond) have also been characterized as the control materials.

Methods

Surface morphology was studied by both scanning electron and atomic force microscopy, and the elastic modulus and the hardness measured by instrumented indentation. Grain analysis was performed on the microscopic images, and statistical analysis was carried out on the results of the nanoindentation measurements.

Results

It was observed that Vertise, Filtek XT and Surefil SDR exhibit stiffness similar to the non-flowable Venus Diamond, whereas Venus Diamond Flow presents itself as the more compliant flowable composite, with Adhese showing intermediate stiffness. Grain analysis of the images confirmed the general rule that the mechanical properties improve with increasing filler loading, with the notable exception of Vertise Flow that shows modulus and hardness as high as 9.1 ± 0.6 and 0.43 ± 0.03 GPa, respectively, for an estimated loading of only ∼40% by volume.

Significance

Whereas generally flowable composites are confirmed not to possess sufficiently strong mechanical properties for bulk restorations, exceptions can eventually be found upon appropriate laboratory screening, as presently seems to be the case for Vertise Flow. However, real practice in actual restorations and respective clinical evaluation are required for final assessment of the suggested results.