Valiant-PhD and Lojic N amalgam alloys: four-year clinical results

From 1984 to 1986, 97 similar pairs of Valiant-PhD and Lojic N amalgam restorations were placed at random by one dentist in Class II cavities prepared in 105 molar and 89 premolar permanent teeth of 73 patients treated in a private practice. Assessments were made of the different handling properties of the two alloys and of the effects of polishing, or otherwise, on the clinical behaviour of the restorations. Valiant-PhD alloy had more 'body' for condensing and was easier to carve and polish than was Lojic N alloy. After periods of up to four years, there was only one restoration failure (from bulk fracture) for each alloy although both materials deteriorated over time. Both the polished and the unpolished restorations showed similar deterioration for marginal fracture and staining, and for surface tarnish, and their initially-different surface textures became more similar during the study. Statistically, Lojic N restorations showed significantly more surface tarnish, but less marginal fracture than did Valiant-PhD restorations, and the tarnishing did not appear to be related to the effects of corrosion.