Gingival response to crowns: a counterpoint.

I thank Dr. Tony Pensak for his interest and comments on my article on gingival response to crowns.1,2 Dr. Pensak is suggesting that the poor gingival response of the 2 maxillary central incisors to the metalceramic crowns (Fig. 1) had more to do with the metallic content of these crowns than their marginal fit and contour. The literature is rich with evidence of longterm success and longevity of metal-ceramic crowns for as much as 23 years, even when they were made by undergraduate students.3–7 Therefore, I am unable to completely agree with Dr. Pensak’s suggestion, as I have no doubt that, in the case I presented, the major cause of the undesirable gingival response following placement of metal-ceramic crowns had more to do with their marginal fit and contour than their metallic content. However, I must agree with Dr. Pensak that the type of metal alloy used for fabrication of metal-ceramic crowns may influence the gingival response to varying degrees. When prescribing metal-ceramic crowns to their patients, dentists are faced with a number of choices of alloys, ranging from high noble alloys with a noble metal content of 60% or higher, to noble alloys with a noble metal content not less than 25%, to base metal alloys. Some base-metal alloys contain nickel, an element with a relatively high sensitivity rate of 4.5% in the general population and considerably higher in females.8 Ideally, metal-ceramic crowns should be fabricated using high-noble or noble metal alloys. If the dentist uses a base-metal alloy to reduce the overall cost of the crown to the patient, the potential for an allergic or sensitivity reaction will be high. This may manifest itself in the form of mild marginal to moderate gingivitis similar to that seen in the clinical cases that Dr. Pensak kindly shared with us. Therefore, although I am sure that in the clinical case I presented, the major causes of the undesirable gingival response were the poor marginal fit of the crowns along with lessthan-ideal gingival contour, I am unable to rule out the possibility of this reaction being compounded by an allergic response to some of the constituents of the metal alloy used in