Introduction. Ocean trenches are natural tectonic plate boundaries between two crustal plates. When a continental plate converges with an oceanic plate a subduction zone forms. The heavier oceanic plate subducts beneath the lighter continental plate forming a trench.
Surgical-Medical Policy this patient has with Arkansas Blue Cross and Blue Shield provides coverage for dental. treatment only in case of accidental injury and accident-related damage to teeth, and then as a rule only to sound. natural teeth. A sound natural tooth is a tooth that is whole, free of decay, periodontal disease or other conditions, and is not in need of treatment for any reason other than accidental injury. DIAGNOSTIC X-RAYS AND THIS COMPLETED FORM ARE REQUIRED TO DETERMINE A. CONSIDERATION OF PAYMENT.
Teeth, as they exist in the mouth, can be placed into any of three broad groupings, the maxillary or mandibular, right or left, anteriors or posteriors. These groupings apply to both the natural dentition and to artificial teeth:  Maxillary or Mandibular. A person has two jaws, a maxillary (upper) and a mandibular (lower). The teeth in these jaws are called either maxillary or mandibular teeth. The combination of natural teeth and supporting alveolar bone that is found in an upper or a lower jaw is called a dental arch .