INSERM, U-897, Bordeaux, F33076, France.
Stat Med. 2012 May 20;31(11-12):1139-49. doi: 10.1002/sim.4459. Epub 2012 Feb 23.
We aim to compare the life expectancy of a filling in a primary tooth between two types of treatments. We define the probabilities that a dental filling survives without complication until the permanent tooth erupts from beneath (exfoliation). We relate the time to exfoliation of the tooth to the age of the child and the time to failure of the filling to the duration since the treatment. We followed up fillings at repeated examinations where information is collected regarding the filling and the tooth. Several fillings can be placed in the same mouth, possibly by the same dentist. To deal with all these particularities, we propose to use a parametric four-state model with three random effects to take into account the hierarchical cluster structure. For inference, right and interval censoring as well as left truncation have to be dealt with. With the proposed approach, we can conclude that the estimated probability that a filling survives without complication until exfoliation is larger for one treatment than for the other, for all ages of the child at the time of treatment.
我们旨在比较两种治疗方法在儿童乳牙填充物的预期寿命。我们定义了在恒牙萌出（换牙）之前，牙填充物没有并发症存活的概率。我们将牙齿的换牙时间与儿童年龄联系起来，并将填充物的失效时间与治疗后的时间联系起来。我们在多次检查中对填充物进行了随访，收集了有关填充物和牙齿的信息。同一口腔中可能会有多个填充物，这些填充物可能是由同一位牙医放置的。为了处理所有这些特殊情况，我们建议使用具有三个随机效应的参数化四状态模型来考虑层次聚类结构。对于推断，必须处理右删失、区间删失和左截断。通过所提出的方法，我们可以得出结论，对于治疗时儿童的所有年龄，一种治疗方法的填充物在没有并发症的情况下存活到换牙的估计概率大于另一种治疗方法。
