Where does microleakage happen on a filling?

Microleakage occurs at the interface between the dental filling material and the tooth structure, particularly at the margins where the filling meets the enamel or dentin. This phenomenon can happen due to the differences in thermal expansion and contraction between the filling material and the tooth, as well as the natural wear and tear over time. Microleakage allows bacteria and fluids to penetrate, potentially leading to secondary caries and pulpal irritation. Proper bonding techniques and materials can help minimize this issue.