The impact of centralized volume-based procurement policy on dental implant procurement volume in medical institutions of a Western Province in China-a single-group and double-group interruption time series analysis

Oral health constitutes a critical component of overall health, and tooth loss significantly compromises quality of life. Dental implants, as an ideal restorative solution, face accessibility challenges due to their high cost. The rapid aging of the population in China—with the proportion of individuals aged 65 and above reaching 14.9%—further intensifies the demand for such treatments. In response, the government implemented a Centralized Volume-Based Procurement for dental implants in 2023, achieving an average price reduction of 55%, with the objective of improving accessibility through the strategy of “Price-Cutting For Volume”. This study utilizes procurement data from a western province(Sichuan Province) before and after the policy implementation to quantify the net impact of the policy on procurement volume, thereby addressing existing research gaps and providing evidence for future policy refinement. Using online procurement data from 1,012 medical institutions in Sichuan Province over a 45-month period (September 2021 – May 2025), an interrupted time series analysis (ITS) was conducted to assess the policy’s net effect on implant procurement volume (the outcome variable), particularly in terms of level and trend changes. Statistical analysis was performed using statsmodels, and the Durbin-Watson (DW) test was applied to detect autocorrelation. The interrupted time series analysis revealed that the Centralized Procurement Policy significantly increased the short-term procurement volume of dental implants, with an overall increase of 7,340.63 units(p < 0.01). Across different types of institutions, procurement volumes increased immediately following the policy implementation across all hospital grades (Tertiary Hospitals: +2,299.26; Secondary Hospitals: +374.30; Primary Hospitals: +47.25; Others: +4,611.01; all p < 0.01). However, the long-term trend revealed a divergence: procurement volumes in high-grade hospitals (tertiary and secondary) remained stable, whereas those in other hospitals—primarily private institutions—demonstrated a significant downward trend (− 157.55 units per month, p < 0.01).Brand-level analysis indicated that while imported products experienced a short-term surge, their growth rate slowed significantly compared to domestic alternatives (trend difference: −190.16 units per month, p < 0.05), signaling the emergence of domestic substitution. Additionally, the procurement volume of Winning products dominated the market (p < 0.01), whereas non-Winning products were not significantly affected. The Centralized Procurement Policy for dental implants significantly boosted procurement demand in a western province(Sichuan Province) in the short term, particularly among high-level hospitals and for imported products. However, a long-term deceleration trend has emerged. Attention should be directed toward insufficient Primary hospitals response, structural adjustments (notably the early stages of domestic substitution), and potential market saturation risks. Complementary measures should be strengthened to ensure the long-term effectiveness and sustainability of the policy.