Supplementary Material for: Cost-effectiveness of silver diamine fluoride depends on caries activity: A decision analytic model

Introduction: The study sought to assess the cost-effectiveness of silver diamine fluoride (SDF) relative to sodium fluoride varnish (NaF), and direct restorations placed chairside or under general anaesthesia (GA), accounting for caries activity.
Methods: An analytical decision tree model was developed with clinical data from multiple centres to evaluate the four treatment options among all children aged 1 to 6 years in Singapore (N=231,880) over a 12-month time horizon. Base-case scenarios consisted of children with low- (1 carious tooth) and high- (7 carious teeth) caries activity. Incremental cost-effectiveness ratios (ICER) and net monetary benefits (NMB) were tabulated with the outcomes set to be the control of active caries and avoidance of tooth extractions. Deterministic and probabilistic sensitivity analyses were conducted.
Results: Overall, SDF was less effective than direct restorations placed chairside but was less costly. For children with low-caries activity, the ICER for SDF was $9 per caries-controlled tooth, and $68 per extraction avoided. For children with high-caries activity, the ICERs were $267 and $1 909 respectively. At a willingness-to-pay threshold of $30, the NMB was negative (favours restorations) for caries control in children with low-caries activity and positive (favours SDF) for all other situations. In the low-caries activity group, SDF had a 41.5% probability of being cost-effective for caries control and 49.2% probability of being cost-effective for the avoidance of extraction. The corresponding probabilities for the high-caries activity group were 99.8% and 100%. The NMB of SDF increases proportionally with caries activity, suggesting utilisation of SDF should depend on caries activity. Results were most sensitive to changes in relative cost, and effectiveness of SDF/direct restorations.
Conclusion: SDF was cost-effective in most situations except for caries control in children with low-caries activity. Direct restorations were more effective and should be considered in low-caries activity children.

Introduction: 研究旨在评估氟化银二胺（silver diamine fluoride, SDF）相对于氟化钠varnish（sodium fluoride varnish, NaF）、椅旁直接修复或全身麻醉（general anaesthesia, GA）下直接修复的成本效益，并考虑龋齿活跃度。
Methods: 本研究基于多中心临床数据构建分析性决策树模型，在12个月的时间跨度内，对新加坡所有1-6岁儿童（N=231,880）的四种治疗方案进行评估。基准情景包括龋齿活跃度低（1颗龋齿）和高（7颗龋齿）的儿童。以控制活动性龋齿和避免拔牙为结局指标，计算并列明增量成本效益比（incremental cost-effectiveness ratios, ICER）和净货币收益（net monetary benefits, NMB），并开展确定性与概率性敏感性分析。
Results: 总体而言，SDF的疗效不及椅旁直接修复，但成本更低。对于龋齿活跃度低的儿童，SDF的ICER为每控制1颗龋齿9美元、每避免1次拔牙68美元；对于龋齿活跃度高的儿童，ICER分别为267美元和1909美元。在30美元的支付意愿阈值下，龋齿活跃度低儿童的龋齿控制NMB为负（倾向直接修复），而其他所有情景的NMB均为正（倾向SDF）。低龋齿活跃度组中，SDF对龋齿控制具有成本效益的概率为41.5%，对避免拔牙的成本效益概率为49.2%；高龋齿活跃度组的对应概率分别为99.8%和100%。SDF的NMB与龋齿活跃度成正比，提示其使用应取决于龋齿活跃度。结果对相对成本及SDF/直接修复的疗效变化最为敏感。
Conclusion: SDF在大多数情况下具有成本效益，仅在龋齿活跃度低儿童的龋齿控制中除外。直接修复疗效更优，应在龋齿活跃度低的儿童中予以考虑。