Eam. Kidd et al., MARGINAL DITCHING AND STAINING AS A PREDICTOR OF SECONDARY CARIES AROUND AMALGAM RESTORATIONS - A CLINICAL AND MICROBIOLOGICAL STUDY, Journal of dental research, 74(5), 1995, pp. 1206-1211
Caries at the margins of restorations is difficult to diagnose. In par
ticular, the relevance of both marginal ditching and staining around a
malgam restorations is unclear. This clinical study questions the rele
vance of marginal ditching and color change to the level of infection
of the dentin beneath the margins of amalgam restorations. Clinically
visible sites (330) on the tooth/restoration margin were selected on 1
75 teeth. The enamel adjacent to each site was noted as stained (a gre
y discoloration) or stain-free. One hundred and seventy-eight sites we
re clinically intact, 83 sites had narrow ditches (< 0.4 mm), and at 4
9 sites, wide ditches were present (> 0.4 mm). Twenty sites with frank
ly carious lesions were also included. Plaque was sampled at the tooth
-restoration margin, and the dentin was sampled at the enamel-dentin j
unction below each site. Samples were vortexed, diluted, and cultured
for total anaerobic counts, mutans streptococci, lactobacilli, and yea
sts. Plaque samples showed that margins with wide ditches (> 0.4 mm) h
arbored significantly more bacteria, mutans streptococci, and lactobac
illi than did clinically intact margins and margins with narrow ditche
s. There were no significant differences in the degree of infection of
the dentin beneath clinically intact restorations and those with narr
ow ditches, but samples associated with wide ditches and carious lesio
ns yielded significantly more bacteria, mutans streptococci, and lacto
bacilli. The color of the enamel adjacent to the sample site was irrel
evant to the level of infection of the dentin beneath the filling marg
in, provided a frankly carious lesion was not present. The results sug
gest that amalgam fillings where margins show wide ditches or carious
lesions should be replaced. Narrow ditches and color change alone shou
ld not trigger the replacement of a filling.