[Non-precious metal dental alloys and allergy]

The fundamental basis of allergy, particularly in relation to contact allergy, is described, together with the importance and frequency of sensitization to nickel, chromium and cobalt in both the consultant and general population. 139 published cases of allergy to dental restorations containing these metals are reviewed involving 92 female and 47 male patients, 115 of whom recovered when the restorations were removed. The most frequent symptoms were local (99/139), particularly gingivitis and stomatitis, while general or remote symptoms occurred in 33 cases. This probably underestimates the true prevalence of the condition, because a large number of reported cases have not been due to their "current appearance". The influence of the occupational environment of the patient is described with special reference to dental technicians. The persistence of contact allergy to metals for which no desensitization is possible is also emphasised. The discussion includes experimental investigations and an appraisal of other methods of revealing hypersensitivity. Finally, some simple recommendations for prevention are made which are of value to practitioners.