Spatial and temporal control is a key advantage for placement and rapid setting of light-activated resin composites. Conventionally, placement of multiple thin layers (<2 mm) reduces the effect of light attenuation through highly filled and pigmented materials to increase polymerisation at the base of the restoration. However, and although light curing greater than 2 mm thick layers is not an entirely new phenomenon, the desire amongst dental practitioners for even more rapid processing in deep cavities has led to the growing acceptance of so-called “bulk fill” (4–6 mm thick) resin composites that are irradiated for 10–20 s in daily clinical practice. The change in light transmission and attenuation during photopolymerisation are complex and related to path length, absorption properties of the photoinitiator and pigment, optical properties of the resin and filler and filler morphology. Understanding how light is transmitted through depth is therefore critical for ensuring optimal material properties at the base of thick increments. This article will briefly highlight the advent of current commercial materials that rationalise bulk filling techniques in dentistry, the relationship between light transmission and polymerisation and how optimal curing depths might be achieved.

空间和时间控制是光活化树脂复合材料放置和快速固化的主要优势。通常，放置多个薄层（<2 mm）会降低通过高度填充和着色的材料引起的光衰减效应，从而增加修复体底部的聚合度。但是，尽管光固化大于2毫米厚的层并不是一个全新的现象，但牙科医生渴望在深腔中进行更快速处理的愿望已导致越来越多的人接受所谓的“大块填充”（4–6毫米厚）的树脂复合材料，在日常临床实践中会被辐照10–20 s。光聚合过程中光透射和衰减的变化非常复杂，并且与光程，光引发剂和颜料的吸收特性有关，树脂的光学性能以及填料和填料的形态。因此，了解光如何通过深度传输对于确保以厚增量为基础的最佳材料特性至关重要。本文将简要介绍目前用于牙科的填充技术合理化的商业材料的出现，光透射与聚合之间的关系以及如何实现最佳固化深度。