恒磨牙玻璃离子窝沟封闭质量与继发龋关系的队列研究及微生态机制探讨

The change of environment is one of most important risk factors of dental caries. For the good features of chemical adhesion, fluoride releasing and hydrophellolic nature, glass ionomer sealant is widely suggested using; however, its low resistance will raise the risk of falling off, which might in turn increase the caries risk. .This prospective cohort study intends to enroll 250 7-to-9-years-old children whose permanent molars have been sealed with GIC sealant, and to collect information about the sealant retention, the dental plaque biofilm, the secondary caries around broken sealant and other related information, using the ICDAS II index, digital image analysis, enamel fluorescence analysis, and to outline the life course of GIC sealant and dental health after being sealed in school-age children in China and to verify the relationship between them. .In turn, analysis based on a nested case-control study design was performing. In it the case group was consist of children with cavitated first molars and the control group was from healthy subjects. Inductively coupled plasma optical emission spectroscopy and high flux gene sequencing technology were performing on the stored bacterial samples of both those case and control group. Concentrations of Ca2+and F- were export and Shannon index, Simpson index, Good's coverage index, Chao index and ACE index were provided,inspectively. By using statistical analysis such as the incidence ,relative risk(RR), Logistic regression analysis, and Cox proportional hazards models, the study intends to screen risk factors of secondary caries around failed fissure sealant, and to clarify the mechanism of sealant retention on tooth level and individual caries risk. This research will provide deep understanding the mechanism of the occurrence of secondary caries disease around occlusal groove and provide a scientific basis for effective caries risk control.

窝沟封闭后每年2%-4%牙发生继发性龋齿；有必要基于龋病生态病因学的观点，研究继发龋的相关因素，促进实现有效防治。项目通过前瞻性队列研究，拟以250名合格学龄儿童为研究对象，实施六龄牙玻璃离子窝沟封闭；应用ICDAS II指数、数字化图像分析、釉质荧光检测、原位pH测定等技术，搜集随后封闭剂的保留情况、菌斑代谢和继发龋齿等信息，定量描绘出第一恒磨牙窝沟封闭后封闭剂保留情况及牙齿健康变化轨迹；进而通过巢氏病例对照研究，以发现釉质成洞病损为病例组，并“1：1”随机配比组成对照组，将冻存菌斑样本进行Ca2+、F-等离子发射光谱和454焦磷酸测序分析，进行发病率、RR值、Logistic回归和Cox比例风险模型等统计分析，筛选出玻璃离子窝沟封闭后继发龋的风险因子，阐明封闭剂保留情况对个体龋患风险的影响规律和机制。本研究将为深入认识窝沟封闭继发龋病的发生机制，实施有效的龋齿风险控制提供高水平的证据。

窝沟封闭技术作为青少年龋齿预防的适宜技术得到广泛接受和临床使用；但是其长期效果仍然难以得到保证，包括脱落率较高，继发龋发生的可能性较大。既往研究更多通过实验室材料学、组织病理学、随机对照的临床研究等方式进行深入探索，而口腔微生态学理论为支撑的队列研究预期为相关领域提供更多的有价值的理论和证据。.本研究将利用已有窝沟封闭防龋技术和口腔微生态学的理论、实验和应用基础，遵循伦理学和知情同意的原则下，基线纳入250名8~9岁小学三年级学生，进行龋风险水平、个体口腔健康状况、口腔知识态度行为等因素的评估，并筛选检查300颗深窝沟的健康牙齿进行树脂和玻璃离子的封闭防龋，分别在封闭后1个月、3个月、半年、1年时进行复查，采用ICDAS II记录窝沟封闭周围的患龋状态，并利用电阻抗技术进行定量评价，采用点位法记录窝沟封闭剂保留情况，采集封闭剂周围的菌斑样本进行实验室分析（qPCR）周围微生态状态。.研究建立起稳定的随访队列，1年的观察期内无一例失访脱落；研究分析发现，1年内的封闭剂保留率达95.4%，无继发龋发生；窝沟封闭剂的脱落与材料、牙位等因素具有相关性，而与儿童个体因素、基线龋风险水平等无相关性。脱落封闭剂周围与完整封闭剂周围以及健康光滑牙釉质的菌斑生物膜有明显差异，在封闭剂边缘菌斑组中，S.mutans、S.sobrinus 和 A.naeslundii 菌种的量在树脂组和玻璃离子组中与脱落程度正相关，完全脱落组多于部分脱落组， 部分脱落组多于未脱落组； L.acidophilus 的菌含量在树脂组和玻璃离子组中与脱落程度负相关， 完全脱落组少于部分脱落组， 部分脱落组少于未脱落组。菌斑生物膜成分的改变，将直接影响局部的龋齿风险，如果能延长观察周期，有可能发现更具实际意义的研究结果。.本研究的实施，建立起一个稳定可靠的随访研究队列中，在项目期限以后也能够随访，搜集更加长时间的纵向资料，提供更有价值的科学数据。研究提出玻璃离子窝沟封闭的操作规范，纵向分析证实能够保证窝沟封闭的质量，更新了在相关方向的认识；同时提出窝沟封闭剂材料的改进在于防龋相关的研究和实践中仍然具有非常重要的意义。探明窝沟封闭剂的存在和脱落，均会对龋高风险位点的微生态产生影响，将为龋病的生态防止提供重要线索。