Guidebook Home

Table of Contents

Preface

Introductory Comments

General Questions About FOP

Genetics of FOP

How FOP Affects the Body

Care and Treatment

Activities

Feelings About FOP

Helpful Addresses

Family Resources

Ideas for Independence

Medical Articles

Acknowledgments and Contributions

Minimizing Risk: Dental Precautions for People with FOP

Frederick S. Kaplan, M.D. and Sharon L. Kantanie

The temporomandibular joints in the jaw are characteristically among the last joints to be affected by Fibrodysplasia Ossificans Progressiva (FOP). However, involvement of the temporomandibular joints has been reported following dental procedures or oral trauma at any age. This, combined with the age-increasing risk that the jaw will become affected by FOP (71% of patients have jaw restriction by age 18), points to the need to take certain precautions to minimize the need for invasive procedures which could result in jaw restriction, or procedures which may be more difficult to deal with as a result of existing jaw restriction.

Preventive dentistry is extremely important for patients with FOP. All affected individuals should have early, regular, and periodic dental visits combined with oral hygiene instruction and nutritional counseling. The additional use of dental sealants, fluoride supplements, and plaque rinses should also be considered. Many individuals have found it helpful to use electric toothbrushes. In addition, the Braun Interclean, an electric flossing system, allows individuals with jaw retriction to floss more easily.

Local/intramuscular injections of anesthetic should be avoided, as reports have demonstrated a clear relationship between the use of local anesthetic during dental procedures and subsequent jaw immobilization. Thirty-six of forty-one (88%) FOP patients who responded to a survey reported having a dental procedure (a filling or extraction). Twenty-one of the thirty-six (54%) who had a dental procedure received an injection of local anesthetic. Five of the twenty-one (24%) who had a local injection reported an immediate FOP flare-up (defined by marked swelling and stiffening leading to permanent loss of jaw motion) within several days of injection. In one case, the stiffening resolved within one week. In three cases, local trauma to the neck or jaw (fall, clothesline injury, bicycle accident) either contributed or led to an FOP flare-up. Twelve others who had comparable work done received no injection. None of these respondents reported a flare-up as a result of the dental procedure. Three participants in the survey did not respond to questions regarding injections.

As the risk of jaw involvement increases with age, based on the ages of respondents, instantaneous flare-ups were expected to occur regardless of trauma. In the group of twenty-one who received an injection of local anesthetic, 0.031 instantaneous flare-ups would have been expected based on statistical evidence. Actual reported flare-ups were 5. In the group of twelve who received no injection, a minimal incidence of flare-up could have been expected to have been reported. Actual results revealed no flare-ups.

At present, it is not possible to determine if the trauma of injection, the local anesthetic agent itself, or a combination of both incited the local ossification process. However, considering the sensitivity of FOP to trauma, it is likely that the trauma of the injections rather than the specific agent injected led to stimulation of heterotopic ossification in the jaw of patients who have FOP (Luchetti et al.).

In general, injections into a muscle should be avoided in patients with FOP. However, local anesthesia can be applied as infiltrations, periodontal ligament (PDL), and interligamentary. Although intramuscular injections do not always provoke new episodes of heterotopic ossification, it is not possible to predict who will develop a problem and who will not. Trauma of any kind may precipitate an episode of FOP. An injection into the muscle is a type of deep trauma.

One patient in the survey reported that surgery to remove the extra bone in the jaw led to a marked worsening of the condition. Crofford et al. in 1990 reported two cases combining surgery with isotretinoin therapy. In both cases, ossification occurred again within two months. All three scenarios corroborate the general view that surgery should be avoided in patients with FOP, as it worsens effects of the disease.

Six patients reported the use of orthodontic appliances during childhood (in place from 6 months to 1 1/2 years). In three cases, this was followed by the use of removable appliances. None of these patients reported any problems as a result of orthodontic procedures. Orthodontic care need not be avoided in FOP patients, but dentists and orthodontists should avoid stretching of the jaw during application or removal of braces or during any other dental procedure (Luchetti et al.).

One patient reported having tooth extractions following ankylosis (restriction) of the jaw in order to facilitate eating. This procedure was performed under general anesthetic and led to no worsening of the condition. A similar procedure would facilitate the performing of dental procedures in cases where the jaw is fused. Under general anesthesia, teeth could be extracted from the back of the mouth, causing minimal cosmetic effect, yet allowing dentists or oral surgeons to perform the needed procedure.

The results of this survey establish that injections of local anesthetic during dental procedures pose substantial added risk for inciting heterotopic ossification and subsequent ankylosis of the temporomandibular joints in patients who have FOP. There appeared to be no significant added risk of immediate heterotopic ossification of the jaw following dental procedures in which there was no injection of local anesthetic (Luchetti et al.). Whenever dental procedures are necessary, the injection of local anesthetic should be avoided if possible. Preventive dentistry that decreases the need for such invasive dental procedures should be considered of utmost importance.

Works Cited and Consulted
Crofford LJ, Brahim JS, Zasloff MA, Marini JC: Failure of surgery and isotretinoin to relieve jaw immobilization in fibrodysplasia ossificans progressiva: report of two cases. J. Oral Maxillofac Surg. 48(2): 204-208, 1990.

Luchetti W, Cohen RB, Hahn GV, Rocke DM, Helpin M, Zasloff MA, Kaplan FS: Temporomandibular joint ankylosis following routine injection of local anesthetic in patients who have fibrodysplasia ossificans progressiva. Oral Surgery. 81: 21-25, 1995.

Nussbaum B, O'Hara I, Kaplan FS. Fibrodysplasia Ossificans Progressiva: Report of a case with guidelines for pediatric dental and anesthetic management. Journ. of Dentistry for Children. Nov/Dec 1996. 448-450.