Clinical , Mechanical and Chemical Evaluation of Amalgam and ART Restorations

描述（由申请人提供）：龋齿（蛀牙）仍然是一个重要的国家和国际健康问题，特别是在低收入和弱势群体中。在美国以外进行的几项临床试验的结果（美国尚未进行研究）表明，在简化和经济的程序中使用玻璃离子水门体（GIC）修复体，称为非创伤修复治疗（ART）技术，在延长修复寿命和减少龋齿复发方面，可能比传统的牙科治疗方法更成功。抗逆转录病毒治疗成功的原因尚不清楚，但有人认为，GIC可能与受龋病影响的组织相互作用，以恢复其部分矿物质含量。当细菌牙菌斑与消耗的可发酵碳水化合物结合时，就会发生龋齿。这种结合产生的酸可以渗透并溶解牙齿表面。GIC是生物相容性材料，技术敏感性低，释放氟化物(F)，造成龋齿病变的内部再矿化。ART是一种“非创伤性”技术，不需要钻牙或麻醉，因此在某些情况下具有优势。汞合金是汞与另一种金属（银）的合金，传统上被牙医用来填补牙洞。在Aim 1中，我们计划对5至11岁的儿童进行一项前瞻性队列研究，这些儿童至少有一颗龋齿（1至3个表面空化）已经用ART或汞合金修复。这些儿童是加州奥克兰亚洲健康服务牙科诊所和旧金山主要是西班牙裔传教会社区的CARECEN牙科诊所的病人，他们将接受初步的牙科评估，包括治疗前的x光片和牙医工作人员的治疗。两家诊所都同意参与并使用这两种材料作为他们日常护理的一部分。将招募符合儿童和牙齿水平选择标准的患者。将进行ART和汞合金修复体的基线临床和影像学评估，以及6个月和12个月的随访评估（无x线片），以评估临床结果：a)龋复发，b)修复体保留，c)修复体边缘完整性。在目标2和3中，将对研究期间自然脱落的修复牙齿进行两种修复材料的分析。在目标2中，我们将研究修复体/牙齿界面的机械性能、微观结构特征（纳米压痕和SEM-EDS），以确定修复材料在组织中引起的变化，并提供可能引起这种变化的机制的见解。在目标3中，我们将评估修复体/牙齿界面（RMS）的化学变化，以确定由牙科材料（GIC和汞合金）与牙组织（牙釉质和牙本质）相互作用引起的再矿化的存在。更好地了解这两种材料在临床、机械和化学性能上的异同，将有助于指导未来在美国使用它们的建议。

DESCRIPTION (provided by applicant): Dental caries (tooth decay) remains a significant national and international health problem, especially in low- income and disadvantaged populations. Results of several clinical trials conducted outside the US (US studies have not been conducted) have suggested that glass ionomer cement (GIC) restorations used in a simplified and economic procedure known as atraumatic restorative treatment (ART) technique may be more successful than conventional dental treatments for large carious lesions with respect to increased restoration longevity and decreased caries recurrence. The reasons for the success of ART have not been clearly established, but it has been suggested that the GIC may interact with the caries affected tissue to restore a portion of its mineral content. Dental caries occurs when bacterial dental plaque combines with consumed, fermentable carbohydrates. This combination produces acids that penetrate and dissolves the tooth surfaces. GIC's are biocompatible materials having low technique sensitivity and release fluoride (F) which creates internal remineralization of a carious lesion. ART is an "atraumatic" technique as no drilling of teeth or anesthesia is required, thus making it advantageous in certain settings and situations. Amalgam is an alloy of mercury with another metal (silver) used traditionally by dentists to fill cavities in teeth. In Aim 1, we plan to conduct a prospective cohort study of initially 5 to 11 year-old children with at least one carious primary molar (1 to 3 surfaces cavitated) that has been restored with ART or amalgam. The children, patients at the Asian Health Services Dental Clinic in Oakland, CA and the CARECEN dental clinic in the primarily Hispanic Mission neighborhood of San Francisco, will receive initial dental assessments including pre-treatment radiographs, and treatment by staff dentists. Both clinics have agreed to participate and use both materials as part of their usual care. Patients that fit the child and tooth-level selection criteria will be recruited. Baseline clinical and radiographic evaluation of the ART and amalgam restorations, and 6-month and 12-month follow-up assessments (without radiographs) will be take place to assess clinical outcomes: a) caries recurrence, b) restoration retention, and c) restoration marginal integrity over time. In aims 2 and 3, analyses of the two restorative materials will be undertaken with restored teeth that naturally exfoliate during the study period. In Aim 2 we will examine the mechanical properties, microstructural characteristics of the restoration/tooth interfaces (Nanoindentation, and SEM-EDS) to identify changes induced in the tissues by the restorative materials and to provide insight to the mechanisms that could induce such changes. In Aim 3 we will evaluate the chemical changes of the restoration/tooth interfaces (RMS) to identify the presence of remineralization caused by the interaction of the dental materials (GIC and amalgam) with the dental tissues (enamel and dentin). A better understanding of the similarities and differences in the clinical, mechanical and chemical properties of these two materials when placed in primary teeth will help guide future recommendations for their use in the US. Public Health Relevance: This clinical translational observational study will allow us to evaluate the effectiveness of two dental restorative materials in two populations of high caries-risk children from lower socio-economic status households, many of whom rely on public assistance. One population is treated at the Asian Health Services Dental Clinic (AHSDC) in Oakland, California and the other at the Central American Resource Center (CARECEN) dental clinic in primarily Hispanic, Mission Neighborhood of San Francisco, California. This research will advance our understanding of the clinical outcomes of atraumatic restorative treatment (ART) vs. traditional amalgam techniques. ART has the advantage of being low cost, relatively easy to apply, especially to young children, and not requiring anesthesia and drilling of teeth. Additionally, the restored teeth will be collected after exfoliation to examine the remineralization process, and mechanical and chemical properties. If the results are favorable for ART with regard to restoration retention, marginal integrity, decreased caries recurrence, remineralization and other interactions with dental tissues, this type of treatment has the potential to impact dental practice, patient management policies, and public health.