复合树脂聚合收缩应力的研究进展

复合树脂作为常用的牙色充填材料,具有美观、操作方便等优点,但也存在聚合收缩、不耐磨、变色等问题.其中,聚合收缩可引起充填复合树脂与牙体之间形成间隙、釉质裂纹和牙尖移动,导致充填失败.影响收缩应力大小的因素包括复合树脂的组成、窝洞形态和临床操作.通过减小聚合收缩应力可提高复合树脂充填的成功率.     

低聚合收缩复合树脂的性能及其应用

聚合收缩是复合树脂的主要缺陷之一,易引起复合树脂与牙体之间形成间隙,产生釉质裂纹和牙尖移动,导致充填失败。近年来,一种以矽油基底基环氧化物为基质成分的新型复合树脂,以低聚合收缩率为特点,成为研究的热点。本文就这种新型复合树脂的性能和粘接等方面作一综述。     

复合树脂充填窝洞聚合收缩应力的控制

目前,用于窝洞充填的光固化复合树脂均存在一定的聚合收缩,其收缩应力在临床中会导致牙体变形、术后敏感、微渗漏和继发龋等问题,从而影响充填修复的效果。下面就复合树脂充填窝洞聚合收缩应力的主要影响因素和临床操作中的控制方法等研究进展作一综述。     

复合树脂聚合性体积收缩的研究进展

光固化复合树脂作为修复和粘接材料虽然具有美观和操作性好等优点,但其聚合时产生体积收缩,造成边缘微漏,导致临床修复失败。近年来,对影响树脂聚合收缩的因素的研究已成为热点。该文就影响树脂聚合收缩的因素做一简要综述。     

显微CT在检测复合树脂聚合收缩中的应用

复合树脂固化时发生聚合收缩,可能会导致最终修复失败或引起其他并发症。应用显微CT(micro-computed tomography,micro CT)可以测量树脂聚合前后的体积变化及由此导致的微渗漏,并可通过示踪颗粒测量树脂聚合收缩矢量,以得到精确的收缩变化的相关数据。这种检测技术无创伤,立体直观,更精确、科学,该文就该技术进行综述。     

软启动照射模式对复合树脂聚合收缩的影响

目的:测定不同光照强度的软启动照射模式下同一种复合树脂的聚合收缩率.方法:采用粘接片(bonded discs)法测定卡瑞斯玛光固化复合树脂(体积38.5 mm3,C值0.47)在不同照射模式(高普40s、高普20 s、高渐进、高脉冲、中普、中渐进、中脉冲、台阶1、台阶2、台阶3)照射3min的聚合收缩率.结果:3种台阶照射模式的聚合体积收缩率均显著大于其他照射模式(P＜0.05);高普20 s模式的聚合体积收缩率显著大于高渐进、高脉冲模式(P＜0.05),但与高普40s相比无显著差异(P＞0.05);中普、中渐、中脉冲照射模式间体积收缩率两两相比均无显著差异(P＞0.05);台阶1照射模式的体积收缩率显著大于台阶2和台阶3(P＜0.05),而后两者无显著差异(P＞0.05).结论:光固化机固有的软启动和脉冲照射模式不能增加树脂的表面流动补偿收缩能力,应用光强更低的前期台阶照射模式则可显著增加树脂的表面流动补偿收缩能力.     

影响复合树脂聚合收缩应力的因素

随着人们对美观要求的日益提高和复合树脂性能的不断完善,复合树脂在口腔临床中的应用已变得日益广泛.目前对复合树脂性能上的改善主要集中在提高其机械性能,减少残余游离单体的释放以增强其生物安全性,减少聚合收缩的程度以防止微渗漏的形成和牙体变形等方面.而树脂发生聚合反应是其自身物理和化学特性所决定的,其收缩产生的应力对复合树脂性能有着重要影响.近年来,对影响树脂聚合收缩应力的因素已成为复合树脂研究的热点,本文就影响树脂聚合收缩应力的因素做一简要综述.     

The polymerization shrinkage of light cure composite resin

The polymerization shrinkage of a number of commercially available composite resin (Starfiil, Durafill, VLC-1 and GD) and an experimental composite #1 which contains 16% DMSOC (a new monomer which expands on polymerization) has been determined using a water-filled dialometer. The results indicated that GD displayed the largest shrinkage value at 2.62 +/- 0.20%, while VLC-1, Durafill and Staifill had smaller values at 2.10 +/- 0.10%, 1.84 +/- 0.20% and 1.42 +/- 0.16%, respectively. The experimental composite. #1 underwent least contraction during setting (0.14 +/- 0.13%). The polymerization shrinkage was influenced by the filler loading and the duration of the exposure to the activating light source. There was little influence of shade of materials on the polymerization shrinkage for VLC-1.     

The effect of resin composite pre-heating on monomer conversion and polymerization shrinkage

ObjectivesTo determine monomer conversion and polymerization shrinkage of a resin composite after different pre-heating procedures and storage intervals.MethodsFor a commercial resin-based composite the immediate (5 min) and final (24 h) degree of conversion was measured on top and bottom surfaces utilizing FTIR spectroscopy. Composite pre-heating temperatures were selected between 10 and 68 °C. Polymerization shrinkage was measured according to Archimedes’ principles of buoyancy after 5 min at respective pre-heating temperatures and after 24 h dark and wet storage at 37 °C. Intra-cavity temperature development was monitored using a K-type thermocouple.ResultsNo significant increase in immediate as well as in final degree of conversion were measured from composite pre-heating at 68 °C compared to 54 and 39 °C. Linear correlations were detected immediately after photo-polymerization and on the top surface after 24 h storage. Polymerization shrinkage as a function of pre-heating temperatures exhibited a linear correlation after 5 min, but no statistically different behavior after 24 h.SignificancePre-heating of resin composites does not increase degree of conversion over time. It can be clinically beneficial, due to a superior marginal adaptation. This advantageous effect of reduced material paste viscosity has to be clinically addressed, since temperature rapidly drops to the physiological level upon removal from the pre-heating device.     

The polymerization shrinkage of composite resins

The majority of methods used for the determination of volumetric polymerization shrinkage rely on mercury as the immersion medium. With current concern for industrial hygiene, the water-filled dilatometer may have advantages. The purpose of this study was to adapt this method for external-energy-cured materials. Six materials were investigated: Aurafill, Silar, Concise, Heliomolar, P-30, and Occlusin. Measurements were taken over one hour, and results ranged from 0.9 to 2.24 volume percent.     

十种纳米填料光固化复合树脂聚合收缩性能的比较与评价

目的 探讨10种纳米填料光固化复合树脂的聚合收缩情况,评价纳米填料在光固化复合树脂聚合收缩性能中的作用.方法 采用激光位移传感器进行非接触式测量,实时监测10种纳米填料光固化树脂(CM:Clearfil Majesty; CX:Ceram·X;F:Fulfil;E:Estelite α;PM:Premisa; TN:Tetric N-Ceram restorative;S:Spectrum TPH3;TB:Tetric Bulk Fill;Z:Z350XT;P:P90)的聚合收缩情况.测量光固化时的体积收缩率、收缩速率峰值以及到达峰值的时间.采用单因素方差分析10种材料的差异.结果 10种纳米填料光固化树脂的体积收缩率差异有统计学意义(P＜0.01).10种纳米填料光固化树脂的体积收缩率范围为1.20％ ～ 3.09％,P＜PM ＜Z≈E ＜TN≈CM≈TB ＜CX ＜S ＜F,其中Z与E、TN与CM间差异无统计学意义,体积收缩率较接近.收缩速率峰值范围为2.14～ 14.76 μm/s,到达峰值的时间范围为3.29～5.39 s.结论 10种纳米填料复合树脂的聚合收缩差异显著,填料含量和粒径对复合树脂聚合收缩有一定影响作用,增加填料含量,减小纳米填料的粒径,有助于降低聚合收缩率.     

复合树脂收缩应力研究进展

复合树脂具有较好的美观性，因此临床应用越来越广泛。但树脂聚合时的收缩应力却影响临床效果，也是人们研究复合树脂的一个焦点。本文就复合树脂收缩应力的产生、影响因素、降低收缩应力的方法及研究收缩应力常用的方法做一综述。     

Relationship among visible light source, composite resin polymerization shrinkage, and hygroscopic expansion

Composite resins contract during polymerization, and studies have shown that light-cured composite resins shrink toward the polymerizing light source. The purpose of this study was to investigate differences in the adaptation of composite resin to the axial wall in Class V restorations following light curing from the lingual or facial aspects. Polymerization contraction in relation to hygroscopic expansion of the restoration was also investigated. Results showed no statistically significant differences (P less than .05) in the adaptation of composite resin to the axial wall, regardless of the polymerization technique, the composite resin, or the effects of hygroscopic expansion.