Root resorption may be a physiological (resorption of deciduous teeth) or a pathological process (resorption of permanent teeth). In the latter case an external and an internal form of resorption can be distinguished. Root resorption may occur on one tooth or on several teeth within a dentition and it may be caused by trauma, periodontitis, orthodontic treatment, internal bleaching, cysts, tumors, or by stimuli from a necrotic dental pulp. Current knowledge concerning the pathogenesis of root resorption and therapeutic approaches are presented. For cervical resorption, it is assumed that the stimulus for the resorbing cells originates from the bacteria within the gingival sulcus and along the affected root surface. The case presented here was initially diagnosed as chronic periodontitis of medium severity. Scaling and root planing were performed resulting in a significant improvement of the periodontal status. Two years later, following a period of irregular recall visits, the patient presented with large areas of cervical resorption on teeth 36 and 37 which made it impossible to preserve these teeth. After another six months, teeth 34 and 35 showed deep destruction caused by external root resorption, mandating the extraction of these teeth as well. Fourteen months later, external root resorptions were evident on teeth 32 and 33, and at the same time, a recurrence of the chronic periodontitis was noted. Periodontal therapy was performed under a systemic antibiotic regime. It was possible to preserve teeth 32 and 33 through surgical crown lengthening procedures. No additional resorption has been observed ever since.