大块充填复合树脂修复后的临床效果的研究进展

目前大块充填复合树脂逐渐应用于牙科治疗中,一些研究发现其除了具有操作简单的优势外,还具有良好的临床效果。单体转化率是反映树脂固化程度的重要指标,也是决定树脂的机械性能和生物学性能的重要因素。牙尖变形、边缘微渗漏是由于复合树脂的聚合收缩产生的收缩应力造成的,对充填体的耐久度、边缘封闭性有一定的影响,可以认为是衡量树脂粘接修复后的临床效果的常见指标。该文主要通过单体转化率、牙尖变形和边缘微渗漏这三方面对大块充填复合树脂修复后的临床效果以及原因机理做一个总结描述。     

大块充填树脂在牙体修复中的应用与研究进展

传统复合树脂在临床应用中分层充填,步骤较多,树脂的聚合收缩可导致修复体边缘微渗漏、术后敏感等,导致修复失败.2009年,大块充填树脂(bulk-fill resin-based composite)应运而生,改良的基质单体、改性强化的纳米混合填料以及独特的光引发剂,使得大块充填树脂能够一层充填4 mm,其简化操作步骤、节约椅旁时间、并能显著降低聚合收缩和聚合应力.本文就大块充填树脂的分类、固化原理、性能等方面进行阐述和讨论,并提出大块充填树脂的应用发展方向.     

大块充填树脂在乳牙修复中的应用和研究进展

大块充填树脂因可以一次性固化4～5 mm的深度而显著缩短了充填时间,并且在聚合收缩、微渗漏、机械强度等方面不逊于传统复合树脂。本文就大块充填树脂的分类、性能、在乳牙修复中的应用等方面进行阐述和讨论。     

新型自固化树脂与常规树脂充填后牙邻面龋的边缘微渗漏及抗疲劳比较

目的:对比新型自固化树脂与常规树脂充填相邻后牙邻面龋后边缘的微渗漏及抗疲劳效用。方法:于2021年1月～12月我院口腔外科收集新鲜离体恒磨牙共112颗,按照充填材料的不同分为自固化组和常规组,各56颗;自固化组采用新型自固化树脂(Surfill)对窝洞进行填充,常规组采用Neofil常规树脂进行填充。观察两组显微硬度、边缘微渗漏深度分级差异、充填体与牙体组织的间距、疲劳试验前后完整边缘情况;采用Pearson和Spearman相关系数分析牙齿抗疲劳度与显微硬度、微渗漏深度优良率及与牙体组织间距的相关性。结果:自固化组硬度值、微渗漏深度分级优良率较常规组均明显升高(P<0.05);自固化组充填体与牙齿组织的间距较常规组明显降低,疲劳试验后两组釉质、牙本质完整边缘百分比值较试验前均明显降低,但自固化组牙釉质、牙本质完整边缘百分比值较常规组显著升高(均P<0.05);相关系数分析牙齿抗疲劳度与固化硬度呈正相关,牙齿抗疲劳度与微渗漏深度优良率及与牙体组织间距均呈负相关(P<0.05)。结论:新型自固化Surfill树脂作为邻面龋充填材料具有更高的固化硬度和粘合度。     

3种树脂材料修复离体牙Ⅱ类洞的边缘裂隙和 微渗漏比较

目的 研究3种树脂材料修复离体牙Ⅱ类洞的边缘裂隙及微渗漏情况。方法 选取符合纳入标准的60颗离体磨牙,随机分为大块充填树脂组、传统树脂组和树脂嵌体组3组,每组20颗。制备Ⅱ类洞,并按照其充填或制作标准进行修复。扫描电镜下测量边缘裂隙宽度,经1%亚甲蓝染色,去除面2.0 mm釉质,抛光后在体式显微镜下观察边缘染色深度。结果 树脂嵌体组的边缘裂隙最小,大块充填树脂组次之,传统树脂组最大,差异具有统计学意义(P<0.05);树脂嵌体组的染色深度明显小于大块充填树脂组和传统树脂组,差异具有统计学意义(P<0.05);大块充填树脂组与传统树脂组间染色深度差异无统计学意义(P>0.05)。结论 从修复体的边缘裂隙和微渗漏两个方面来看,树脂嵌体效果良好,值得临床推广应用。     

SOFT-START光聚合技术对复合树脂充填体边缘微渗漏影响的实验研究

目的 :探讨SOFT -START光聚合技术对光固化复合树脂充填后边缘微渗漏的影响 ,为该技术的推广应用提供实验依据。方法 :选择因正畸需要拔除的第一前磨牙的志愿者 2 0人共 80个牙 ,随机分成 4组 ,每组 2 0个牙。在每个牙牙合面中央制备Ⅰ类洞 ,常规酸蚀、冲洗、吹干、涂布粘接剂。 1组、2组 :充填Z2 5 0树脂 ,3组、4组 :充填Charisma树脂 ;1组、3组采用传统光固化方式固化 ( 75 0W /cm2 × 40s) ;2组、4组 :采用SOFT -START光聚合技术固化 ( 2 0 0W /cm2 × 10s ,75 0W /cm2 × 3 0s)。所有牙充填后在口内留置 7d后拔除 ,0 .5 %品红溶液渗入法染色 ,体视镜下观察 ,判定微渗漏程度。结果 :采用SOFT -START光聚合技术组充填体微渗漏程度显著低于传统固化方式组。结论 :SOFT -START光聚合技术有助于减少光固化复合树脂的聚合收缩 ,可提高充填体边缘封闭性 ,减少微渗漏产生     

光照射后固化对于大块充填树脂性能的影响

光照射后固化因为有利于大块充填树脂各种性能的提高,日益引起关注.其中光照射后固化对于提高复合树脂双键转化率、增加硬度、减小聚合收缩应力均有较好的效果.温度、光固化反应的双键转化率、树脂组成成分和浸泡溶剂等因素都可以影响大块充填树脂的光照射后固化.本文将对以上内容及其对临床意义进行综述.     

Ceramage聚合瓷嵌体和纳米树脂嵌体边缘微渗漏的对比研究

对于牙体大面积缺损,树脂嵌体修复是近年来一种新型修复技术,与树脂直接充填修复相比较,树脂在体外经二期固化处理后,抗压强度、硬度、耐磨性、恢复邻接关系等方面具有较好的临床效果[1]。Ceramage聚合瓷是近年来一种新型瓷化树脂,主要用于制作冠、贴面、嵌体、高嵌体等。然而嵌体的边缘线较长,发生微渗漏的可能性较大,且不同树脂嵌体材料与牙体间微渗漏的程度也不同[2]。     

复合树脂的分层充填固化技术

复合树脂是临床广泛应用的一种牙体缺损充填修复材料.复合树脂固化过程中伴随的体积收缩最终使充填修复体边缘密合性下降,出现微裂隙,产生微渗漏现象,进而导致修复体边缘变色等一系列不良后果.     

复合树脂充填Ⅴ类洞微渗漏研究进展

复合树脂材料凭借良好的美学效果,操作简便,对温度具有绝缘性,且能最大程度保留健康牙体组织等优点而被广泛应用于牙体缺损的修复。但因其固化时会发生聚合收缩,使复合树脂与牙体之间形成数微米的边缘裂缝,即边缘微渗漏,从而导致充填修复失败。由于牙颈部缺损的Ⅴ类洞在龈缘处的釉质较少,边缘微渗漏更易发生。微渗漏是一种多因素共同作用的复杂过程,相关研究报道也很多。本文通过复习相关文献,就影响复合树脂充填Ⅴ类洞后微渗漏的多种因素作一综述,以期为临床实践提供参考和帮助。     

Clinical performance and chemical-physical properties of bulk fill composites resin —a systematic review and meta-analysis

Objectives: The objective of this study was to perform a meta-analysis of clinical and laboratory studies to compare the performance of bulk-fill and conventional composite resins in terms of polymerization shrinkage, polymerization stress, cusp deflection, marginal quality, degree of conversion, microhardness, flexural strength, fracture strength and clinical performance. Data: One hundred three articles were included in this study, and the Peto method was used to compare the bulk-fill and conventional composites using the RevMan software. Sources: Searches were performed in the PubMed and Scopus databases. Study selection: Laboratory studies and randomized clinical trials comparing one of the previous detailed outcomes between bulk-fill and control composites were included. Conclusions: The bulk-fill composite resins showed less shrinkage, polymerization stress, cusp deflection and microhardness than conventional composites, while both materials presented a similar marginal quality, flexural strength and fracture strength. Also, bulk-fill materials with regular viscosity showed similar shrinkage. The conversion of bulk-fill materials with flowable consistency were similar to conventional composite resins with a thickness of up to 2 mm and greater than conventional composites with a thickness greater than 2 mm. Despite these in vitro differences, the clinical performance of bulk-fill and conventional composite resins was similar in randomized clinical trials, with one to ten years of follow up. In conclusion, the bulk-fill materials show better or similar performance to the conventional materials in clinical trials and laboratory studies in terms of volumetric shrinkage, polymerization stress, cusps deflection and marginal quality, with the only exception being the lower level of microhardness observed for bulk-fill composites with thickness up to 2 mm.     

Light-curing considerations for resin-based composite materials: a review. Part II

As discussed in Part I, the type of curing light and curing mode impact the polymerization kinetics of resin-based composite (RBC) materials. Major changes in light-curing units and curing modes have occurred. The type of curing light and mode employed affects the polymerization shrinkage and associated stresses, microhardness, depth of cure, degree of conversion, and color change of RBCs. These factors also may influence the microleakage in an RBC restoration. Apart from the type of unit and mode used, the polymerization of RBCs is also affected by how a light-curing unit is used and handled, as well as the aspects associated with RBCs and the environment. Part II discusses the various clinical issues that should be considered while curing RBC restorations in order to achieve the best possible outcome.     

Light-curing considerations for resin-based composite materials: a review. Part I

There has been a continual advent of improved technologies in dentistry. Among these are the material sciences of resin-based composites (RBCs). Since the introduction of light-cured RBCs, the problem of polymerization shrinkage and the methods used to overcome this have concerned clinicians and researchers. Types of curing light and modes of curing have been shown to affect the degree of polymerization and related shrinkage of RBCs. This review, which is divided into two parts, discusses the contemporary light-curing units. Part I explores the evolution in light-curing units and different curing modes. Part II highlights the clinical considerations regarding light curing of RBCs that are important for achieving optimal curing and maximum polymerization of RBCs in a clinical setting.     

Evaluation of polymerization shrinkage of bulk-fill resin composites using microcomputed tomography

This study evaluated the influence of cavity depth on polymerization shrinkage of bulk-fill resin composites with and without adhesive resin. Standardized     

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??Composite resins are widely used as clinical restoration materials because of good aesthetic properties??easy handling??thermal insulation and better conservation of tooth structures. However??its polymerization shrinkage can lead to the gap between the tooth structure and composite resin called microleakage??which can result in the failure of restorations. Cervical lesions usually have little enamel in Class?? cavities??so it’s more difficult to avoid the microleakage. Microleakage is a complicated process caused by various factors and there are many studies about it reported. Based on literature reviews??this paper summarized the influence factors of microleakage in Class?? composite restorations??hoping to offer some reference and help in clinical treatment.     

Visible light-curing: part II

Multiple studies on composite light-curing have focused on the effects of polymerization contraction stresses on restoration margins. Those stresses can potentially cause debonding of restorations and gap formation if they exceed resin bond strengths to enamel and dentin. Such gaps may permit microleakage, resulting in postoperative sensitivity or clinical failure of the restorative treatment. The effects of polymerization shrinkage are dependent on the configuration of the cavity, properties of the restorative material, and the kinetics of polymerization shrinkage. This review analyzes several studies that have been published on the subject     

In vitro cuspal deflection and microleakage of maxillary premolars restored with novel low-shrink dental composites.

OBJECTIVES: The development of novel low-shrink resin-based composites (RBCs) may offer a potential reduction in polymerisation shrinkage stresses generated at the tooth/restoration interface compared with current methacrylate RBCs. In vitro cuspal deflection and microleakage of meiso-occlusal-distal (MOD) cavities restored with experimental oxirane and silorane (EXL596 and H1) and methacrylate (Z100 and Filtek Z250) RBCs were assessed. METHODS: Standardised pre-molar MOD cavities were prepared (n = 10) and restored with each material. The flexure of buccal and palatal cusps was recorded 0.1 h following irradiation utilising a differential transformer deflection gauge. Each restored tooth was subjected to a thermocycling regime and microleakage of tooth sections were assessed following 24 h immersion in 0.2% fuschin dye. The degree of conversion (DC) of each RBC material was also assessed using Fourier transform infrared (FTIR) spectroscopy following 0.1, 0.5, 1, 4, 24 and 48 h post-irradiation. RESULTS: A total cuspal deflection was observed for EXL596 (2.5 +/- 0.9 microm) and H1 (6.0 +/- 1.8 microm) compared with Z100 (20.0 +/- 4.7 microm) and Filtek Z250 (16.5 +/- 3.3 microm) following 0.1 h. The cavities restored with EXL596 displayed significantly higher microleakage than any other RBC and H1 exhibited non-significant and significantly decreased microleakage compared with Z100 and Filtek Z250, respectively. The DC of EXL596 and H1 was significantly decreased compared with Z100 and Filtek Z250 following 0.1, 0.5 and 1 h. SIGNIFICANCE: The 'living' polymerisation associated with the novel oxirane and silorane RBCs and the associated decrease in cuspal deflection may suggest a decrease in the magnitude of polymerisation shrinkage stress at the tooth/restoration interface. The decreased DC following 0.1 h of the oxirane compared with the methacrylate RBCs has provided information on the cure rate of cationic and free-radical polymerisation mechanisms, respectively. The inadequate marginal seal of cavities restored with EXL596 would preclude its use as a dental restorative. The reduction in cuspal deflection and decrease in microleakage of cavities restored with H1 compared with Filtek Z250 may be advantageous in terms of marginal integrity following placement. However, the non-significant difference in microleakage between the H1 and Z100 may only present modest decreases in the deleterious effects of shrinkage stress.     

3D mapping of polymerization shrinkage using X-ray micro-computed tomography to predict microleakage

ObjectivesThe objectives of this study were to (1) demonstrate X-ray micro-computed tomography (μCT) as a viable method for determining the polymerization shrinkage and microleakage on the same sample accurately and non-destructively, and (2) investigate the effect of sample geometry (e.g., C-factor and volume) on polymerization shrinkage and microleakage.MethodsComposites placed in a series of model cavities of controlled C-factors and volumes were imaged using μCT to determine their precise location and volume before and after photopolymerization. Shrinkage was calculated by comparing the volume of composites before and after polymerization and leakage was predicted based on gap formation between composites and cavity walls as a function of position. Dye penetration experiments were used to validate μCT results.ResultsThe degree of conversion (DC) of composites measured using FTIR microspectroscopy in reflectance mode was nearly identical for composites filled in all model cavity geometries. The shrinkage of composites calculated based on μCT results was statistically identical regardless of sample geometry. Microleakage, on the other hand, was highly dependent on the C-factor as well as the composite volume, with higher C-factors and larger volumes leading to a greater probability of microleakage. Spatial distribution of microleakage determined by μCT agreed well with results determined by dye penetration.SignificanceμCT has proven to be a powerful technique in quantifying polymerization shrinkage and corresponding microleakage for clinically relevant cavity geometries.