LONGEVITY AND CARIOSTATIC EFFECTS OF EVERYDAY CONVENTIONAL GLASS-IONOMER AND AMALGAM RESTORATIONS IN PRIMARY TEETH - 3 YEAR RESULTS

The aim of this study was to compare the longevity and cariostatic eff ects of everyday conventional glass-ionomer and amalgam restorations i n primary teeth. The materials consisted of 515 Ketac-Fil glass-ionome r restorations and 543 Dispersalloy amalgam restorations prepared in 6 66 children, from 3 to 13 years of age, by 14 dentists within the Dani sh Public Dental Health Service in the municipalities of Vaerlose and Hillerod. The restorations, of which 79% were of the Class II type, we re in contact with 593 unrestored surfaces in adjacent primary and per manent teeth. After 3 years, 6% of the patients had dropped out of the study, and 33% of the teeth were exfoliated with the restoration in s itu. A further 37% of the glass-ionomer and 18% of the amalgam restora tions were recorded as failed (p < 0.001). The frequency of failures w as highest for Class II glass-ionomer restorations, which showed a 50% median survival time of only 34 1/2 months, because of many fractures , while the 75% survival time for Class II amalgam restorations just e xceeded the actual 36 months (p < 0.001). Caries progression was most often recorded in surfaces adjacent to amalgam restorations, and 21% o f these surfaces needed restorative treatment vs. 12% of the surfaces adjacent to glass-ionomer restorations (p < 0.01). The three-year resu lts indicated that conventional glass ionomer is not an appropriate al ternative to amalgam for all types of restorations in primary teeth. I n particular, the short longevity of Class II glass-ionomer restoratio ns could not be compensated for by the reduced caries progression and need for restorative therapy of adjacent surfaces.