300 Theories and techniques of oral implantology

periosteum, it should be pushed back into place after the implant has been removed. The fragment should be stabilized by suturing. In cases where the fractured portion has very little periosteum attached, it should be removed; otherwise, it will become necrotic and act as a foreign body. It is interesting to note that while these fragments become necrotic and must be removed from the maxillae, they form sequestra in the mandible. Whenever possible, the fractured portions should be retained in order to preserve the proper ridge contour.

Mandibular nerve damage

If the patient complains of pain or sensitivity while the dentist is boring with the burs and taps or inserting the implant, the operator should stop as soon as the symptom occurs, x-ray the area, and apply pressure on the implement in all directions to see if any pain is created. If the radiograph reveals that the bur or implant is in or nearly in direct con-tact with the neurovascular bundle and if the patient has sensitivity, the offending implement should be removed. No implantation is possible.

If, however, the x-ray shows the bur or implant to be a safe distance from the nerve and if the patient has no hypersensitivity upon percussion, the intervention may continue. The pain or sensitivity could very well have been caused by heating of the bone by the drill as it approached the canal. It is not necessary in these cases to bore deeper. The implant should be set with the utmost precaution, and only the events during healing can determine whether or not to remove the implant.

When the dental canal is injured and the nerve affected, the principal symptom is a paresthesia of the lower jaw that usually persists after the local anesthesia wears off. The paresthesia is generally unilateral and extends from the corner of the lips anteriorly and inferiorly to the midline of the injured jaw. Its nature is variable. It can occur as a slight burning sensation, hypersensitivity to thermal or tactile stimuli, a sensation of swelling, and vague or unpredicted pain. Sometimes these symptoms are intermittent, appearing only with cold weather, and they very seldom become worse. However, paresthesias can be very annoying and depressing. In time, the lesion usually heals and normal sensitivity returns. Total paresthesia is rarely permanent, al-though there have been cases in which the nerve lesions have not regenerated.

If injury to the dental canal or nerve has occurred, the operator may leave the implant in posi

tion and check the patient frequently for pain and paresthesia. If the pain is lessening, the implant can remain for a time, providing there is little or no paresthesia and no congestion between the implant and the dental canal. If the pain increases and a definite paresthesia or congestion is present, the implant should be removed.

After paresthesia necessitates the removal of an implant, a true neuritis may appear. This might make it difficult to determine whether the remaining pain results from the osseous lesion left by the removal of the implant or from the lesion of the nerve itself.

The treatment of a patient whose implant has been removed because of nerve damage involves the administration of vitamins B, and B,z intramuscularly three times a week and of various pain relievers, if necessary. Generally the damage to the nerve is less severe than it may have first appeared, and the patient will recuperate in from 2 to 6 months.

Maxillary perforations

Whereas injuring a nerve is a major threat in the mandible, such an incident is rare in the maxillae. What is to be avoided is perforating or penetrating a maxillary sinus or the nasal vestibulum.

The sinus floor is lined with a mucosal membrane, the schneiderian membrane. If this has been elevated, but not punctured, by the implant, the implant may remain. Sometimes, however, the proximity of the implant to the membrane causes pain and swelling. If these symptoms cannot be alleviated by systemic antibiotics and pain-relieving drugs, the implant must be removed.

If the membrane has been perforated, the implant should be removed immediately. Perforation can be determined by having the patient blow his nose while the operator watches the implant site for air or mucus, or by the excessive amount of bleeding that sometimes takes place.

Usually the sinus floor will heal with no post-operative incidence. When sinus drainage persists, the situation can be improved by inhaling steam and using ephedrine nose drops. In those few cases where a suppurative sinusitis develops, the patient should immediately be given antibiotics. If severe infection persists, the patient should be referred to a rhinologist.

In those extremely rare situations in which an implant has been completely lost in the maxillary sinus, and if it cannot be removed via its entrance