1 Inflammation of the gingiva, bone loss, and increased gingival recession may progress slower than with other forms of periodontitis.  Periodontitis Associated with Systemic Diseases - Systemic diseases, such as heart disease, diabetes, and certain forms of arthritis, may have a correlation with periodontitis.
Along Faults. Earthquakes can also occur far from the edges of plates, along faults. Faults are cracks in the earth where sections of a plate (or two plates) are moving in different directions. Faults are caused by all that bumping and sliding the plates do. They are more common near the edges of the plates.
Most earthquakes happen at a place where 2 tectonic plates touch. Earthquakes occur mostly in regions with stress between continental plates. This is the case in the Middle East, and along the rim around the Pacific Ocean (where it also causes volcanic activity in the regions, known as the Ring of Fire).