Introduction
Drug-induced gingival enlargement is classified by the
American Academy of Periodontology as a dental plaque-induced gingival disease,
as evidence suggests that existing
gingival inflammation may be necessary for its development and that proper
plaque control and effective oral hygiene can lessen its severity or
potentially prevent its occurrence altogether. 2
Currently, there are over 20 medications from three pharmaceutical categories
including anticonvulsants, calcium channel blockers and immunosuppressants that
are associated with gingival enlargement.4 It is the responsibility of the dental
practitioner to recognize the potential of these medications to contribute to
gingival enlargement and to provide the proper prophylactic care or appropriately
refer the patient for periodontal therapy.
A team approach involving a consultation with a periodontist and the patient’s
physician is a critical step in successful treatment.
Risk factors
During a course of treatment with a medication
implicated in the pathogenesis of drug-induced gingival enlargement, poor plaque
control is the most significant risk factor associated with its
development. The severity of enlargement
is often proportional to the amount of gingival inflammation present and not
the dosage of medication. Overall, males
tend to be affected three times as often as females and age is inversely
correlated with likelihood of occurrence.
Medication
Prevalence of gingival enlargement with phenytoin (Dilantin®) use has been shown to be up to 50%, while other anticonvulsants such
as valproic acid, Phenobarbital® and Tegretol® have
been shown to be rarely associated with the disorder. Of the calcium channel blockers, nifedipine
(Adalat®, Procardia®) and
diltiazem (Cardizem®) are the most likely to cause gingival enlargement
(5-20%) while amlodipine (Lotrel®, Norvasc®),
felodipine (Aggon®, Plendil®) and
verapamil (Calan®, Covera®) are
far less likely to be implicated.
Cyclosporin A, an immunosuppressant commonly used in organ transplant
patients, has been shown to be associated in 25-30% of adult patients and over
70% in children, while tacrolimus has a significantly lower association at 14%.
Pathogenesis
While the physiology behind drug-induced gingival
enlargement has not been definitively elucidated, histopathologic studies have
shown that the gingival tissue volume increase is due to an excessive
accumulation of extracellular matrix proteins including collagen and ground
substance with a predominance of plasma cells.
Hence, the increase in tissue volume is primarily a connective tissue
response and not epithelial. Recent
evidence suggests that this overgrowth could occur not from over-production of
collagen, but rather through prolonged cell life of keratinocytes. Another hypothesis is that fibroblasts in
susceptible patients are sensitive to the medication in question, causing
increased protein, and hence collagen, production.
Clinical presentation
Clinically, gingival enlargement frequently appears
within 1-3 months of the initiation of treatment with the offending medication.
The facial surfaces of the gingiva in anterior sextants are often most severely
involved, and the patient may present with inflamed, fibrotic masses spreading
from the interdental papillae to the attached gingiva that may interfere with
mastication, speech and esthetics. Due
to discomfort secondary to inflammation and the physical topography of the
enlarged gingiva, oral hygiene may be impaired and diet can be adversely
affected. This can lead to a host of
other problems including caries, periodontal disease and immunosuppression
secondary to malnutrition.
Treatment and prevention
Meticulous oral hygiene and plaque control combined
with the removal of local factors are essential for any patient taking drugs
associated with gingival enlargement. A
three-month periodontal maintenance interval is strongly recommended as
well. While excellent oral hygiene and professional
plaque control can potentially prevent or lessen the severity of the condition,
they often are insufficient for reversing the process once established. It is therefore prudent to consult the patient’s
physician to discuss potential drug substitutions that may result in regression
of the lesions with proper supportive periodontal care and oral hygiene. After drug substitution or withdrawal,
evidence suggests that gingival lesions may resolve in 1-8 weeks in some
patients.In transplant patients, however, drug substitution or cessation may
not be an option due to the risk of transplant rejection. Treatment of gingival enlargement in patients
taking cyclosporin A should focus on their chronically immunosuppressed
state. In these patients, evidence
suggests that topical antifungal treatment such as Nystatin lozenges, chlorhexidine
rinses or a short course of azithromycin (3-5 days; 200-500 mg/day) can be
effective. There is evidence that systemic
azithromycin remains effective in reducing gingival overgrowth from three
months to two years after treatment, but this data is controversial. A topical treatment including scaling and
root planing in conjunction with an azithromycin-containing toothpaste used
twice daily for one month has been shown to be effective in reducing gingival
overgrowth as well, but the long-term efficacy of this treatment is unclear.
If the patient has gingival
overgrowth and is currently taking:
|
Discuss
the following substitution with the primary care provider:
|
Nifedipine
(6-15%)
|
Isradipine, Amlodipine,
Verapamil, Felodipine
|
Phenytoin
(50%)
|
Carbamazepine, Valproic
Acid, Vigabatrin, Phenobarbitone
|
Cyclosporin
A
(Adults 25-30%,
Children >70%)
|
Tacrolimus
|
Note: incidence of gingival
enlargement in parentheses. Table
adapted from Dongari-Bagtzoglou 2004.
While non-surgical therapy and, if possible, drug
substitutions should be attempted first, surgery is often necessary to fully correct
the esthetic and functional impairment encountered in this disorder. Surgical excision has been successful in
non-responding nifedipine cases when combined with good oral hygiene as well as
in cases associated with verapamil and diltiazem, but it does tend to recur.A
classic external bevel gingivectomy is an option to reduce redundant
tissue. An internal gingivectomy
approach, however, has been advocated due to its ability to provide primary
closure and reduce the incidence of postoperative bleeding, discomfort and
infection. Due to its technical difficulty,
this procedure may be best referred to a periodontist. Another surgical option is the CO2
laser due to its decreased surgical time, rapid hemostasis and its
compatibility with a host of underlying medical conditions.
Recurrence
Eighteen months after surgical therapy, the recurrence
rate of gingival overgrowth in patients taking cyclosporin A or nifedipine was
34% in a study of 38 individuals. Age,
gingival inflammation and attendance at recall visits are all significantly
related to recurrence. To help prevent
recurrence post-surgically, chlorhexidine rinse twice daily is recommended.
Conclusion
Drug-induced gingival enlargement
is a common sequela to treatment with anticonvulsants, calcium channel blockers and immunosuppressants. Evidence suggests that gingival inflammation
is critical in its pathogenesis. While
it may be prevented through meticulous periodontal maintenance and home care,
it is essential for the dentist to work together with the patient’s physician
and periodontist in order to successfully treat this condition once it occurs.