###Human: Why did a large part of tooth broke off while eating soft food? ###Assistant: Hi. A certain type of decay starts in small pits on the tooth surface (pit caries). Progression pattern of that caries is like a triangle with the base facing inside and tip at the surface. So it will not be visible in its early stages but inside decay will be bigger in size. While you bite something hard, there is a chance of P as it is under surface being eroded. Consult a dentist at the earliest and get restoration (depends on the extent. May be normal filling or RCT).