In general, health conditions or habits that prevent you from healing appropriately may restrict someone from getting dental implants.
People who smoke or drink alcohol in excess fall under this category. Smoking restricts oxygen brought to your body and thus slows down your body’s ability to heal. It is highly suggested you quit smoking, if not permanently, at least during your dental implant process. The same goes with consuming alcoholic beverages.
If you have gum disease, you may not be eligible for dental implants. If it is in its earliest stages, you can have gum disease treated, and you will be able to get dental implants afterward. If, however, you have advanced gum disease, there is no cure, but periodontal maintenance and care can be provided for your gum disease.