People lose their teeth to three primary processes: periodontal disease (gum and bone deterioration), tooth decay (or cavities) and unstable chewing systems.
Gum disease and dental decay are primarily caused by the presence of bacterial plaque. So plaque control is at the center of preventing these diseases. There is some risk beyond your control for the first two diseases because some people have softer, more penetrable enamel. Some people can also have a stronger immune response to the bacteria, and that reaction causes periodontal breakdown.