Cross-reactivity between gutta-percha and natural rubber latex: assumptions vs. reality.
BACKGROUND
Immunological cross-reactivity between gutta-percha and natural rubber latex, or NRL, has not been demonstrated clearly despite recent concerns and several suspected cases reported in the literature.


METHODS
The authors analyzed aqueous extracts of commercial gutta-percha points and raw gutta-percha samples for cross-reactivity to NRL by radioallergosorbent test, or RAST, inhibition; immunoblot inhibition; direct enzyme-linked immunosorbent assay, or ELISA; and ELISA inhibition using sera from NRL-allergic people as the source of anti-NRL immunoglobulin E, or IgE, antibodies. To confirm in vitro results, the authors conducted skin prick testing, or SPT, on a patient with type I NRL allergy using aqueous extracts from raw gutta-percha, ammoniated gutta-percha and gutta-percha points.


RESULTS
Aqueous extracts from commercial gutta-percha points did not cross-react to NRL in RAST inhibition or immunoblot inhibition, ELISA or ELISA inhibition assays. However, three of 13 sera from subjects with type I NRL allergy exhibited IgE binding to raw gutta-percha extracts in direct ELISA. Moreover, in ELISA inhibition, the binding of IgE to raw gutta-percha extracts was inhibited in a dose-dependent manner by raw NRL and vice versa. SPT results from a subject with type I NRL allergy were positive for NRL and raw gutta-percha extracts but negative for gutta-percha point extracts.


CONCLUSIONS
The authors found no detectable cross-reactivity between NRL and commercial gutta-percha points. However, their ELISA and SPT results demonstrated that some allergenic cross-reactivity exists between raw gutta-percha and raw NRL.


CONCLUSIONS
Gutta-percha alone is not likely to induce symptoms in patients with type I NRL allergy. However, other materials used in obturating root canals may be irritating and potentially allergenic in patients with pre-existing allergies.
Hamann
Curt
C
SmartPractice, Phoenix, Ariz 85008, USA. hamann@smarthealth.com
Rodgers
Pamela A
PA
Alenius
Harri
H
Halsey
John F
JF
Sullivan
Kim
K
D000906:Antibodies / Q000276:immunology; D000937:Antigen-Antibody Reactions / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006171:Gutta-Percha / Q000009:adverse effects*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology; D020315:Latex Hypersensitivity; D011506:Proteins; D011852:Radioallergosorbent Test; D012387:Root Canal Filling Materials; D012408:Rubber; D012882:Skin Tests
D000906:Antibodies; D011506:Proteins; D012387:Root Canal Filling Materials; D007073:Immunoglobulin E; D006171:Gutta-Percha; D012408:Rubber