Re-mineralising, antibacterial composites and adhesives for more durable, conservative and pain less tooth restoration

蛀牙是由特定的产酸细菌引起的，这些细菌会使牙釉质和牙本质脱矿。如果不加以控制，牙本质牙髓复合体的感染和相关的疼痛就会发生。治疗费用会上升几倍，特别是如果最终需要进行根管治疗或用种植体替换牙齿。龋齿是人类最常见的疾病。近40%的英国成年人至少有一颗未经治疗的蛀牙。在贫困国家，儿童或全体人口中，这一比例上升至60-90%。龋齿引起的疼痛和牙齿脱落对生活质量有重大的不利影响。受损或感染的牙齿结构必须部分或全部更换，以阻止疾病进展，保持功能和改善美观。牙齿修复治疗使英国人的牙齿能够保持更长时间。然而，由于它们的寿命有限，修复维护的财务成本很高。汞合金修复越来越多地被更美观的白色复合材料所取代。复合材料具有良好的强度和耐磨性，但将它们粘到牙齿上的程序很复杂，需要熟练的牙医。复合材料置换的主要原因是细菌和酶共同作用导致胶粘剂失效。这种失败使牙齿和修复体之间形成微间隙，更多的细菌和酶可以通过微间隙进入。由于复合材料没有抗菌作用，因此会发生再感染。另一种治疗方法是抗逆转录病毒疗法。非创伤修复技术（ART）最初是为世界上电力供应有限、无法获得牙医和相关基础设施（如牙科椅、压缩空气等）的地区开发的。然而，由于减少了局部麻醉/钻孔的使用和更简单的操作，它也受到儿童的青睐。它使用手动器械去除大部分的蛀牙组织，然后用玻璃离子水泥（GIC）密封腔体。密封可以阻止任何剩余感染的传播。GIC /牙本质结合的良好耐久性使这种方法在小的牙槽中成功，但由于GIC强度差，在较大的修复体中失败是常见的。因此，本研究的目的是开发更容易放置的新材料，具有复合材料的高强度，但具有GICs的牙本质粘附耐久性。这些新材料包含牙科复合材料和gic以及磷酸钙骨水泥的组合成分。此外，它们还含有用于漱口水的抗菌剂和食品防腐剂。有效的抗菌性能将使材料的放置不需要完全去除感染的牙齿组织。此外，这些材料会释放出磷酸钙，磷酸钙可以消除细菌造成的脱矿损害，从而稳定牙本质，对抗酶。这将使更高比例的原始牙齿结构得以保存。新材料的其他智能特性将包括它们在细菌存在时抗菌和磷酸钙释放的增加。此外，在咀嚼或大的温度变化（例如喝热饮或吃冰淇淋）造成的任何损伤后，它们将具有自我修复的能力。结论将增加修复寿命，减少与龋齿相关的疼痛和费用。

Dental caries is caused by specific acid producing bacteria that demineralise enamel and dentine. If left unchecked, infection of the dentine pulp complex and associated pain occurs. Treatment costs then escalate several folds, particularly if root canal procedures or tooth replacement with implants is ultimately required. Dental caries is the most common disease in humans. Almost 40% of UK adults have at least one untreated carious tooth. This rises to 60-90% for children or across the whole population in deprived nations. Pain and tooth loss from dental caries is associated with significant adverse impact on quality of life. Damaged or infected tooth structure must be partially or totally replaced in order to halt disease progression, preserve function and improve aesthetics. Tooth restoration treatments have enabled the UK population to keep its teeth for longer. The financial cost of restoration maintenance, however, is high due to their limited lifetime expectancy. Amalgam restorations are increasingly being replaced by more aesthetic white composites. Composites have good strength and wear resistance but the procedures used to bond them to teeth are complex and require a skilled dentist. The main reason for composite replacement is adhesive failure due to combined bacterial and enzyme action. This failure enables microgap formation between the tooth and restoration through which more bacteria and enzymes can penetrate. As composites have no antibacterial action re-infection subsequently occurs. An alternative method of treatment is the ART approach. The atraumatic restorative technique (ART) was originally developed for regions of the world with limited electricity supply and no access to dentists and the associated infrastructure eg dental chair, compressed air etc. It is also favoured, however, by children due to reduced use of local anaesthetics / drills and greater procedure simplicity. It uses hand instruments to remove the bulk of the carious tissue and then a glass ionomer cement (GIC) to seal the cavity. Sealing halts the spread of any remaining infection. The good durability of the GIC / dentine bond has enabled this method to succeed in small cavities but failure in larger restorations is common due poor GIC strength. The aim of this study is therefore to develop new materials that are simpler to place, have the high strength of composites but the dentine adherence durability of GICs. These new materials contain a combination of components from dental composites and GICs but also calcium phosphate bone cements. In addition they contain antibacterial agents used in mouth washes and food preservatives. Effective antibacterial properties will enable the materials to be placed without the need for total removal of infected dental tissue. Furthermore the materials will release calcium phosphates that can undo the demineralisation damage caused by bacteria and thereby stabilise dentine against enzymes. This will enable a higher percentage of the original tooth structure to be preserved. Further smart features of the new materials will include their increase in antibacterial and calcium phosphate release in the presence of bacteria. Moreover, they will have the ability to self repair after any damage caused by chewing or large temperature variations (for example upon drinking hot drinks or eating ice cream). The conclusion will be increased restoration longevity and reduced pain and cost associated with dental caries.