A STUDY OF NI-RESISTANT BACTERIA ON THE RESTORED STAINLESS STEEL CROWN

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Journal of the Korean Academy of Pediatric Dentistry 2000;27(2):274-282.
Published online May 31, 2000.

A STUDY OF NI-RESISTANT BACTERIA ON THE RESTORED STAINLESS STEEL CROWN

기성금관 수복어린이에서의 니켈내성균에 관한 연구

정샛별, 이긍호

경희대학교 치과대학 소아치과학교실

Abstract

Stainless steel crowns are widely used for restoration for primary molars. The material used for the crowns is an alloy of 70~80% nickel and 5~15% chromium. Nickel has been known to cause allergic reaction, cancer and cell toxicity. Little is known about nickel with respect to the relationship between Ni-contained SS crown and graining of Ni-resistance in oral microorganisms. The purpose of this study is to examine whether use of Ni-contained SS crown leads to occurrence of Ni-resistant microorganism, especially enterococci. The gingival crevicular fluid of two different groups was taken. Experimental group included patients wearing SS crown, and control group comprised individuals without SS crown. The samples were plated in BHI agar, BHI agar supplemented with nickel chloride at the concentration of 3mM and bile esculin azide (BEA) agar. The cultured enterococci on BEA agar medium were tested their Ni-resistance in nickel-containing media increasing concentrations from 3mM to 50mM. The results were as follows: 1. In experimental group, a total of 507,350 strains were isolated on BHI agar, of which 53,864(10.62%) strains were found to be resistant to 3mM nickel. In control group, of 414,590 isolates on BHI agar, 37,523 isolates were resistant to 3mM nickel. 2. A total of 95 enterococci were isolated on BEA agar in experimental group, while 20 were isolated in control group. of the enterococci, 68 and 12 isolates were found to be nickel-resistant in experimental and control group, respectively. 3. Of 68 nickel-resistant isolates in experimental group, one survived 50mM nickel. In contrast, none of the isolates in control group was observed to grow at the concentrations over 30mM nickel.

Key Words: Stainless steel crown, Ni-resistant microorganism, Enterococci