Fleming G J P, Khan S, Afzal O, Palin W M, Burke F J T
Materials Science Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, Trinity College Dublin, Dublin 2, Ireland.
J Dent. 2007 Feb;35(2):97-103. doi: 10.1016/j.jdent.2006.05.003. Epub 2006 Jul 13.
To investigate the polymerisation shrinkage strain, associated cuspal movement, degree of conversion (DC) and cervical gingival microleakage of mesio-occlusal-distal (MOD) cavities restored with four resin-based composite (RBC) filling materials placed incrementally using a light emitting diode (LED) light curing unit (LCU).
Standardised extensive MOD cavity preparations on extracted teeth were performed on 40 sound upper premolar teeth. Restoration of the teeth involved the placement of RBCs in eight increments with the appropriate bonding system before irradiation using an LED LCU. Buccal and palatal cusp deflections at each stage of polymerisation were recorded using a twin channel deflection measuring gauge. Following restoration, the teeth were thermocycled, immersed in a 0.2% basic fuchsin dye for 24 h, sagittally sectioned and examined for cervical microleakage. The DC was determined using a Fourier transform infra-red (FT-IR) spectrometer.
No significantly difference (P=0.677) in cuspal movement was recorded for Z100 (13.1+/-3.2 microm) compared with Filtek Z250 (8.4+/-3.5 microm), P60 (7.3+/-3.8 microm) and Admira (6.7+/-2.7 microm). The LED LCU deflections were compared with a halogen LCU used in a conventional (Fleming GJP, Hall D, Shorthall ACC, Burke FJT. Cuspal movement and microleakage in premolar teeth restored with posterior filling materials of varying reported volumetric shrinkage values. Journal of Dentistry, 2005;33:139-146) and soft-start mode (Fleming GJP, Cara RR, Palin WM, Burke FJT. Cuspal movement and microleakage in premolar teeth restored with posterior filling materials cured using 'soft-start' polymerization. Dental Materials, 2006, , in press) and a significant reduction in cuspal movement was identified for curing type and material type (P<0.001 and P=0.002, respectively). No significant differences were noted between the four RBC materials investigated when the DC or microleakage scores were examined for the LED LCU.
It would appear that irradiation of RBCs using the LED LCU offered a significant reduction in associated cuspal movement in large MOD cavities. However, the microleakage scores following polymerisation were significantly increased with dye penetration into the pulp chamber from the axial wall evident in teeth restored with the LED LCU.
研究使用发光二极管（LED）光固化机（LCU）逐层放置四种树脂基复合材料（RBC）补牙材料修复近中-咬合-远中（MOD）洞时的聚合收缩应变、相关牙尖移动、固化程度（DC）和颈部牙龈微渗漏情况。
在40颗完好的上颌前磨牙上制备标准化的大面积MOD洞。使用合适的粘结系统，在使用LED LCU照射前，分八层放置RBC材料修复牙齿。使用双通道挠度测量仪记录聚合各阶段的颊尖和腭尖挠度。修复后，对牙齿进行热循环处理，浸入0.2%碱性品红染料中24小时，矢状面剖切，检查颈部微渗漏情况。使用傅里叶变换红外（FT-IR）光谱仪测定DC。
Z100（13.1±3.2微米）的牙尖移动与Filtek Z250（8.4±3.5微米）、P60（7.3±3.8微米）和Admira（6.7±2.7微米）相比，差异无统计学意义（P = 0.677）。将LED LCU的挠度与传统方法（Fleming GJP、Hall D、Shorthall ACC、Burke FJT。用报道的不同体积收缩值的后牙补牙材料修复前磨牙的牙尖移动和微渗漏。《牙科杂志》，2005年；33:139 - 146）和软启动模式（Fleming GJP、Cara RR、Palin WM、Burke FJT。用“软启动”聚合固化的后牙补牙材料修复前磨牙的牙尖移动和微渗漏。《牙科材料》，2006年，待发表）中使用的卤素LCU进行比较，发现固化类型和材料类型的牙尖移动有显著降低（分别为P < 0.001和P = 0.002）。在检查LED LCU的DC或微渗漏评分时，所研究的四种RBC材料之间未发现显著差异。
使用LED LCU照射RBC材料似乎能显著降低大型MOD洞中相关的牙尖移动。然而，LED LCU修复的牙齿中，聚合后微渗漏评分显著增加，染料从轴向壁渗入牙髓腔明显可见。
