There are two main signs something is wrong. The first one is infection. The unique thing about implants that make them so strong, is the osseointegration. This is the process where the implant becomes integrated with the bone. This is where issues can arise if infections occur, as it can stop the integration or damage the bone. If there is an infection, there may be pain, swelling and it will be hot.
The second sign is if the implant starts moving around. A dental implant is made up of three parts. A titanium implant, the crown ‘tooth’, and the abutment that joins them together. All three parts can become loose or break. At first, it may be unnoticeable or a micro-movement, but over time the movement becomes more pronounced. It will wiggle when talking or chewing. This may be due to a broken abutment or crown, as these can wear down and fracture. Or, it can be due to the implant becoming loose.
There is also the small chance that the crown may not be perfectly the right size. It may be causing food to get stuck between the natural tooth and the implant. If this is the case, the crown can easily be replaced.