teriorly. The binding fibers traverse these structures, compartmentalizing them. The submucosal layer thins as it approaches the alveolar ridge and its attached gingiva, so much so that the juncture (3) of the marginal palatal mucosa and that of the gingiva is almost indistinguishable.

When teeth are present, strong fibers also run from the lamina propria to the cervical region of the tooth and to the marginal areas of the alveolar process. These fibers are usually lost with the teeth.

The similar density and elasticity, combined with the blending of gingival into palatal tissues, is a distinct benefit to the implantologist. When little attached gingiva remains over a highly resorbed ridge, the palatal tissue may be repositioned as a "graft" over the crest to insure that the protruding posts of either an endosteal or subperiosteal implant are encircled by the ideal type of tissue for a tight, elastic cuff. This ease of tissue substitution occurs only in the maxillae. In the mandible, it may be necessary to use a palatal graft to recreate a similarly favorable situation. The firm attachment of the soft tissues in the palate, together with the compact palatal bone's hardness, also make some portions of the palate potentially good subperiosteal implant sites.

In edentulous maxillary spans, particularly posteriorly, the number and density of the thick elastic fibers (4) and their inter-twining with the exposed bone trabeculae (5) make it difficult to cleanly separate the periosteum from the bone and properly expose the site. Jagged, torn tissues heal poorly, and epithelial remnants may be pushed into and sealed within the implant socket to proliferate and prevent adequate healing.

The density of the tissues also increases the difficulty in pushing them away from bone. Fortunately, the vital blood vessels and nerves of the area are encased in a sleeve of much looser connective tissue (6). Thus they can freely slip within their sleeve, avoiding being constricted or torn as the operator works under them.

On the outer, or buccal/labial, surface of the dental arch, the gingiva is sharply divided from the vestibular alveolar mucosa (7) by a scalloped line, the mucogingival junction (8). Whereas the gingiva is firmly attached and pink in color, due to the thickness and texture of the tissue layers above the blood vessels, the alveolar mucosa is mobile and red, having numerous small vessels near its surface. The mobility, as well as the delicacy, of the alveolar mucosa, contributes to the unsuitability of the posterior upper

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