Background For financial reasons, dental prosthetics is one of the major unmet dental healthcare needs [Financial-SUN (F-SUN)]. Private fees for dental prosthetics result in significant out-of-pocket payments for users. This study analyzes the impact of geo-variations in protheses fees on dental F-SUN. Methods Using a nationwide French declarative survey and French National Health Insurance administrative data, we empirically tested the impact of prosthetic fees on dental F-SUN, taking into account several other enabling factors. Our empirical strategy was built on the homogeneous quality of the dental prosthesis selected and used to compute our price index. Results Unmet dental care needs due to financial issues concern not only the poorest but also people with middle incomes. The major finding is the positive association between dental fees and difficulty in gaining access to dental care when other enabling factors are taken into account (median fee in the highest quintile: OR = 1.35; P value = 0.024; 95% CI 1.04–1.76). People with dental F-SUN are those who have to make a greater financial effort due to a low/middle income or a lack of complementary health insurance. For identical financial reasons, the tendency to give up on healthcare increases as health deteriorates. Conclusions The results underscore the need for fee regulation regarding dental prosthetics. This is in line with the current French government dental care reform.