into the anterior palatine nerve and the shorter middle and posterior palatine nerves. The anterior palatine nerve enters the oral cavity at the major palatine foramen and turns sharply anteriorly, following a course similar to that of the major palatine artery. The nerve splits into numerous branches that fan out and supply the palatine mucosa up to the midline medially, the palatal gingiva

laterally, and the canine region anteriorly. In the canine region, it exchanges fibers with the nasopalatine nerve, which has descended through the incisive foramen and fanned out over the anterior portion of the maxilla.

The middle and posterior palatine nerves supply the soft palate and the palatine tonsil.

When a tooth or teeth have been lost, their attendant vessels diminish in number. Thus the maxillary residual ridge will have far less sensory nerves than it did with teeth present. This makes the area much less sensitive to pain. Patients who complain of pain due to implants, particularly in the posterior regions, are probably suffering from referred pain from an exposed nerve in the maxillary sinus.

Although the maxillae share numerous nondental functions, particularly respiratory, with other bones of the upper face, the nerves supplying these functions are well out of the range of any implant procedure. No major dental nerve passes within implant range in most cases; only the residual fibers in the alveolar ridge are intercepted.

Care must be taken in incising and reflecting palatal tissue. Neither nerves nor arteries in the posterior portion of the palate should be interrupted. Anteriorly, the consequences are less severe, but should be avoided if possible. Normally, palatal vessels lie away from the incision site itself, and because they can slip within their connective tissue sleeves, there is little danger of tearing them.

In most cases where the vessels run a fairly normal course, there is comparatively little difficulty in dealing with maxillary in-nervation.

Stress Adaptations

The upper and lower jaws have adapted to mechanical stress, which affects the mass and ultimately the volume of bone in very

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