Tooth whitening materials have not undergone relevant advances in the last years. Current materials base their action on the oxidant activity of peroxides, which present the disadvantage of requiring long application times, along with unpleasant side effects of dental hypersensitivity (e.g. sharp pain). In this work, a novel tooth whitening formulation based on the encapsulation of a reducing agent (sodium metabisulfite) in liposomes is developed. An experimental design was applied to optimize the formulation in terms of whitening action and safety, using bovine teeth as in vitro model. Results were obtained by colorimetry, profilometry and nanoindentation techniques. The comparison with standard whitening treatments showed a similar whitening action of the optimized formulation but in remarkable shorter application times. Moreover, teeth roughness values obtained with the presented formulation conformed with ISO 28399. As mechanism of action, results obtained from fluorescent confocal microscopy showed the liposomal formulation to form a layer surrounding the enamel surface, enhancing the treatment efficacy in terms of diffusion of the protected reductant towards the enamel. The better efficiency of this formulation encourages its use as an alternative to current oxidative treatments.

牙齿美白材料在过去几年没有经历相关的进展。当前材料的作用基于过氧化物的氧化活性，其缺点是需要较长的应用时间，以及牙齿过敏的令人不快的副作用（例如剧痛）。在这项工作中，开发了一种基于将还原剂（焦亚硫酸钠）封装在脂质体中的新型牙齿美白配方。应用实验设计优化配方在美白作用和安全性方面，使用牛牙作为体外模型。结果是通过比色法、轮廓测定法和纳米压痕技术获得的。与标准美白处理的比较表明，优化配方具有相似的美白作用，但使用时间明显缩短。此外，使用所提出的配方获得的牙齿粗糙度值符合 ISO 28399。作为作用机制，从荧光共聚焦显微镜获得的结果显示脂质体配方在牙釉质表面形成一层，在受保护的扩散方面提高了治疗效果对搪瓷的还原剂。这种配方的更高效率鼓励将其用作当前氧化处理的替代品。