Rubber Dam and Latex Allergy

A review of Rubber dam sheets is not complete without a working knowledge of rubber dam and latex allergies
The incidence of hypersensitivity reactions to natural rubber latex(NRL)has risen significantly since the late 1980s. This is purely attributed tothe rising awareness among health care professionals. The Food and DrugAdministration attributes this rise to a ten-fold increase in the use of latexgloves and in the field of dentistry the use of rubber dam too is on the rise.While only approximately 1–6 percent of the general population is allergic to latex, the prevalence in health care workers and others whose occupations involve exposure to rubber products is around 10 percent.¹

WHAT IS LATEX

Latex is a generic term designating a water emulsion, or a liquid dispersed within another liquid.

Latex is a common component of many medical and dental supplies. These include disposable gloves, dental dams, airway and intravenous tubing, syringes, stethoscopes, catheters, dressings and bandages

NRL is composed of rubber particles and water, and contains 256 proteins, including 11 being potentially allergens. Although some of chemicals and additives used in latex manufacturing are implicated as being responsible for dermatitis and other irritations, true latex allergies usually occur in response to the naturally occurring proteins found in latex.²

WHAT IS LATEX ALLERGY

Latex allergy is an immediate hypersensitivity response to proteins found in natural rubber latex.
The response can begin within minutes of exposure to the allergen (protein) and can take the form of an urticaria (hives) if exposure is through the skin, or respiratory symptoms (wheezing, runny nose, sneezing) if the allergen is inhaled. In some cases, an anaphylactic reaction (facial swelling, difficulty in breathing, and a severe drop in blood pressure) may occur if the protein is introduced directly into the blood. This immediate type of hypersensitivity or true allergic reaction to NRL is most likely to be found in those individuals who have multiple allergies and are frequently exposed to NRL products. Because of a similarity of proteins, individuals allergic to latex may also be sensitive to foods such as peanuts, bananas,lactose intolerant etc. Patients should be informed of this potential cross allergenicity.

Immediate hypersensitivity reactions occur within 20 min of exposure to the antigen and should be managed more aggressively. The signs and symptoms of this type of reaction include hives, itching, facial swelling, difficulty breathing, increased heart rate, and low blood pressure.

If the patient does exhibit signs of cardiovascular or respiratory distress, additional medical intervention would include basic life support measures, emergency medical assistance, administration of oxygen, and intramuscular or subcutaneous administration of epinephrine. The adult dosage is 0.3 to 0.5 mg of 1: 1000 epinephrine, and the child dosage is 0.25 mg. Epinephrine can also be administered through use of an EpiPen every 5 to 20 min as needed for a total of three doses.

Delayed hypersensitivityreactions are manifest generally as skin reactions: Itching, redness, dry skin, fissures, and sores. These reactions occur 1 to 48 h after exposure to the antigen. Should a patient develop any these conditions, the dental procedure should be discontinued and the patient removed from direct contact with latex containing products (e.g.
rubber dam and gloves). Immediate management of delayed hypersensitivity reactions includes monitoring of vital signs and the administration of an oral antihistamine, either diphenhydramine or chlorpheniramine. The oral dose of diphenhydramine for adults is 25 to 50 mg three to four times a day, and for children over 20 lbs, the oral dose of diphenhydramine is 12.5 to 25 mg three to four times a day. For chlorpheniramine, the oral adult dosage is 2 to 4 mg three to four times a day, and the children’s dosage is 2 mg every 4 to 6 h.

Gutta-percha and Latex Allergy:As a result of the chemical similarity between natural rubber and gutta-percha, the material used in filling the root canal, questions have arisen concerning its use in patients with a history of natural rubber latex allergy. To date, there’s only one report of a supposed allergic reaction to gutta-percha. There is, however, no definitive proof that the patient had a true allergic reaction to the gutta-percha.

Gutta-percha used in dentistry and the natural rubber latex found in treatment gloves and rubber dams are significantly different. Gutta-percha is derived from the juice of the Taban tree (lsonandra percha), which is in the same botanical family as the rubber tree (Havea brasiliensis). Gutta-percha occurs naturally as 1,4-polyisoprene and is harder, more brittle, and less elastic than natural rubber. Modern commercially prepared gutta-percha obturation cones contain approximately only 20% of the natural product. The difference in
chemical make-up and manufacturing process of natural rubber latex and gutta-percha could produce minimal cross-reactivity.
A consultation with the patient’s allergist should be made prior to initiating the obturation phase of treatment. The contents of dental gutta-percha and the technique to be used should be discussed with the physician.

PRECAUTIONARY MEASURES

A complete medical history and dental history should include identifying patients with a history of latex allergy or those at high risk for being allergic. Precautions must be taken to safely treat these patients.

1. Hypoallergenic” gloves and rubber dams in which the manufacturer has removed most of the allergy-causing chemicals can be substituted. If, however, the patient has an immediate type of allergy to the proteins found in natural latex, vinyl or nitrile rubber gloves and dams must be used.
2. The latex free products should be stocked separately,they should not be in contact with latex products.
3. The patient must have no contact with latex containing dental handpiece hoses, suction hoses, latex nitrous oxide unit nosepieces and hoses
4. In addition, thought should be given to treating the patient as the first appointment in the day in order to minimize exposure to airborne particles of latex.
5. Special latex-free rooms may be necessary for the most severe cases
6. If the patient has a documented latex allergy, but has not been tested for sensitivity to gutta-percha, then immunological testing for gutta-percha sensitivity is strongly advised.

RISK FACTORS FOR ALLERGIC REACTIONS TO LATEX

Many dental professionals come into contact with latex products every day (i.e., examination gloves, dental dams, tubing, etc.). This repeated exposure can increase the risk of developing a latex allergy.

Oil-based hand lotions can cause gloves to deteriorate and solubilize latex proteins, increasing the risk of allergic skin response, such as itching, redness or rash.

Powdered latex gloves, the natural rubber latex protein combined with the powder and could become airborne when the gloves were removed. The airborne mix could’ve been inhaled, triggering an allergic reaction. The powder used in latex gloves may also be related to cutaneous reactions, such as delayed wound healing.

People who have had multiple surgeries also may be at increased risk of latex allergy.(due to frequent intubations, catheterizations etc)

Hand gloves and rubber dam are indispensable in routine dentistry. Awareness of the risk factors and its efficient management is essential to a safe dental practice.

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