RELATIONSHIP BETWEEN THE SEASONALITY OF THE AMAZON RIVER AND THE PROVISION OF DENTAL TREATMENTS IN THE MUNICIPALITY OF PARINTINS, AMAZONAS: A TEMPORAL ANALYSIS FROM 2018 TO 2025

Abstract

River dynamics constitute a significant factor regarding mobility and access to health services in Amazonian municipalities. This study aimed to analyze the relationship between monthly variations in the Amazon River level and the volume of dental treatments recorded in the Unified Health System (SUS) in the municipality of Parintins, Amazonas, from 2018 to 2025. This is a retrospective, descriptive, and analytical ecological study employing a quantitative approach and time-series analysis. Hydrological data were obtained from the National Water and Basic Sanitation Agency (ANA) via the Parintins gauging station (ID 16350002), while healthcare data were extracted from the SUS Outpatient Information System (SIA/SUS), specifically focusing on subgroup 0307 (dental treatments). A total of 96 monthly periods were analyzed. During this timeframe, 55,497 dental treatments were recorded, with a monthly average of 578.1 procedures. Spearman correlation analysis revealed a weak positive association between the average monthly river level and dental treatment volume over the entire period (ρ = 0.218; p = 0.033). The correlation remained significant after excluding the year 2020 (ρ = 0.256; p = 0.019), while a moderate correlation was observed between 2022 and 2025 (ρ = 0.532; p < 0.001). A significant reduction in treatment volume was also observed in 2020, consistent with healthcare service disruptions related to the COVID-19 pandemic. The study concludes that river seasonality is associated with the volume of dental treatments in Parintins, although healthcare-related and contextual factors also exert significant influence. Incorporating hydrological information into health planning can contribute to strategies better suited to the territorial specificities of the Amazon.