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 Raíza Dias , Moro Bruna Lorena Pereira , Pontes Laura Regina Antunes , Maia Haline Cunha Medeiros , Passaro Ana Laura , Oliveira Rodolfo Carvalho , Garbim Jonathan Rafael , Vigano Maria Eduarda Franco , Tedesco Tamara Kerber , Deery Christopher , Raggio Daniela Prócida , Cenci Maximiliano Sergio , Mendes Fausto Medeiros , Braga Mariana Minatel ,   CARDEC collaborative group - CARDEC-03 trial, Passaro Ana Laura , Serra Annelry Costa , Silva Antonio Carlos Lopes , Moro Bruna Lorena Pereira , de Picoli Acosta Carolina , Laux Caroline Mariano , Saihara Cíntia Saori , Raggio Daniela Prócida , Mendes Fausto Medeiros , Maia Haline Cunha Medeiros , da Costa Isabel Cristina Olegário , de Almeida Isabella Ronqui , Vargas Jhandira Daibelis Yampa , Garbim Jonathan Rafael , Imparato José Carlos P. , Freitas Julia Gomes , De Natal Karina Haibara , Pontes Laura Regina Antunes , Bifulco Mariana , Braga Mariana Minatel , de Araújo Mariana Pinheiro , do Vale Mayume Amorim , Freitas Raiza Dias , Samuel Renata Marques , Baronti Rita , de Carvalho Oliveira Rodolfo , Cesar Simone , Novaes Tatiane Fernandes , Tedesco Tamara Kerber , Gimenez Thais , Lenzi Tathiane Larissa , Signori Cacia , Cenci Maximiliano Sérgio , Ekstrand Kim Rud 
Published: November 2021

Abstract
Background
Different approaches have been used by dentists to base their decision. Among them, there are the aesthetical issues that may lead to more interventionist approaches. 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 approaches 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 and extrapolating these findings to a longer time horizon.

Methods
A trial-based economic evaluation will be conducted, including three cost-effectiveness analyses (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 2 years, and we will adopt the societal perspective. The average costs per child for 24 months will be calculated. Three different cost-effectiveness analyses (CEA) will be performed. For CEAs, the effects will be the number of operative interventions (primary CEA analysis), the time to these new interventions, the percentage of patients who did not need new interventions in the follow-up, and changes in children’s oral health-related quality of life (secondary analyses). For CUA, the effect will be tooth-related 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 and probabilistic sensitivity analyses to handle uncertainties. The net benefit will be calculated, and acceptability curves plotted using different willingness-to-pay thresholds. Using Markov models, a longer-term economic evaluation will be carried out with trial results extrapolated over a primary tooth lifetime horizon.

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 2 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, these trial-based economic evaluations may bring actual evidence of the economic impact of such interventions.

Trial registration
NCT03520309. Registered May 9, 2018. Economic evaluations (the focus of this plan) are not initiated at the moment.