The economic impact of two diagnostic strategies in the management of restorations in primary teeth: a health economic analysis plan for a trial-based economic evaluation
Authors: Freitas Raiza Dias , Moro Bruna Lorena Pereira , Pontes Laura Regina Antunes , Maia Haline Cunha , Passaro Ana Laura , Oliveira Rodolfo Carvalho , Garbim Jonathan Rafael , Vigano Maria Eduarda , Deery Cristopher , Raggio Daniela Prócida , Cenci Maximiliano Sergio , Mendes Fausto Medeiros , Tedesco Tamara Kerber , Braga Mariana Minatel , CARDEC collaborative group 
Published: July 2021

Background
Different approaches have been used in the clinical routine to assess restorations and determine the need for further reinterventions. In general, dentists based their decision in different parameters, including aesthetical ones, leading to a more interventionist approach. Indeed, using a more interventionist strategy (the World Dental Federation - FDI), more replacements tend to be indicated than using a minimally invasive one (based on the Caries Around Restorations and Sealants -CARS). Since the resources related to the long-term health effects of these strategies have not been explored, the economic impact of using the less invasive strategy is still uncertain. Thus, this health economic analysis plan aims to describe methodologic strategies for conducting a trial-based economic evaluation that aims to assess whether a minimally invasive strategy is more efficient in allocating resources than the conventional strategy for managing restorations in primary teeth.
Methods
A trial-based economic evaluation will be conducted, including three cost-effectiveness analysis (CEA) and one cost-utility analysis (CUA). These analyses will be based on the main trial (CARDEC-03/NCT03520309), in which children aged 3 to 10 were included and randomized to one of the diagnostic strategies (based on FDI or CARS). An examiner will assess children's restorations using the randomized strategy, and treatment will be recommended according to the same criteria. The time horizon for this study is two years, and we will adopt the societal perspective. The average costs per child for 24 months will be calculated. Three different cost-effectiveness analysis (CEA) will be performed. For CEAs, the effects will be the number of operative interventions, the percentage of patients who did not need new interventions in the follow-up, and the scores obtained with a questionnaire to assess children’s oral health-related quality of life. For CUA, the effect will be quality-adjusted life-years (QALYs). Intention-to-treat analyses will be conducted. Finally, we will assess the difference when using the minimally invasive strategy for each health effect (∆effect) compared to the conventional strategy (based on FDI) as the reference strategy. The same will be calculated for related costs (∆cost). The discount rate of 5% will be applied for costs and effects. We will perform deterministic one-way and probabilistic sensitivity analyses to handle uncertainties. The net benefit will be calculated, and acceptability curves plotted using different willingness-to-pay thresholds. A longer-term economic evaluation will be carried out with trial results extrapolated over a primary tooth lifetime horizon using Markov modelling methods.
Discussion
The main trial is ongoing, and data collection is still not finished. Therefore, economic evaluation has not commenced. We hypothesize that conventional strategy will be associated with more need for replacements of restorations in primary molars. These replacements may lead to more reinterventions, leading to higher costs after two years. The health effects will be a crucial aspect to take into account when deciding whether the minimally invasive strategy will be more efficient in allocating resources than the conventional strategy when considering the management of restorations in primary teeth. Finally, patients/parents preferences and consequent utility values may also influence this final conclusion about the economic aspects of implementing the minimally invasive approach for managing restorations in clinical practice. Therefore, this trial-based economic evaluations may bring actual evidence of the economic impact of such these interventions.
Trial registration:
NCT03520309. Registered May 9th, 2018. Economic evaluations (the focus of this plan) are not initiated at the moment.