Secondary Occlusal Trauma
When a patient exerts abnormally heavy biting forces on the teeth, stress cracks, chips and wear may result. This is known as primary occlusal trauma. Primary occlusal trauma implies there has been no loss of the periodontal attachment (gingival attachment fibers, periodontal ligament, or bone), and the teeth themselves are damaged by the excessive forces on them.
Secondary occlusal trauma occurs when there has been some degree of periodontal attachment loss, and normal biting forces which were once tolerated by the gums, periodontal ligaments and bone are now too excessive for those structures to withstand. The result is loosening, tipping and movement of the teeth. Frequently primary and secondary occlusal trauma are both present in the same patient, who may have areas that are periodontally healthy and others that are not.